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Proceedings of the Chemical Society. August 1957 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue August,
1957,
Page 217-240
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PROCEEDINGS OF THE CHEMICAL SOCIETY AUGUST 1957 THE INDUSTRIAL FUND FOR THE ADVANCEMENT OF SCIENTIFIC EDUCATION IN SCHOOLS By D. B. BRIGGS (SENIOR TO THE FUND) ASSESSOR DURINGthe last twenty or thirty years there has been a considerable growth in the amount of science taught throughout the country. The romance of the subject its intellectual disciplines and its unlimited practical applications in a rapidly changing world have contributed to this growth. Schools in particular have gone a long way towards making science an essential part of a pupil’s education at one stage or another and within their limitations of teaching accommoda- tion have made it possible for those who are capable of studying the subject to an advanced level to do so.In this Headmasters have been encouraged by the increased tendency of pupils to stay at school longer than they used to do. At higher levels Technical Colleges and Universities are steadily increasing facilities for the study of various branches of Pure and Applied Science. As far as it goes all this is encouraging but the disturbing fact remains that the rising demand for scientific manpower cannot adequately be met. In the White Paper on “Technical Educa- tion” published in 1956 this national shortage problem was firmly stated and various lines of action were outlined. In 1954 and 1955 a number of leading companies engaged in chemical elec- trical and engineering fields considered what steps industry could take to increase the numbers of scientists and technologists in the future.Everything pointed to the schools as a promising field and in November 1955 the Industrial Fund for the Advancement of Scientific Education in Schools came into being. Its object was to help Independent and Direct Grant schools financially with capital grants for building expanding modernising and equipping science buildings. Maintained schools were excluded since they are the concern of the Local Education Authori- ties. Once the decision to assist schools had been taken other companies added their support until eventually 143 of them contributed more than three million pounds-mostly in the form of covenants. Action promptly followed. A detailed ques- tionnaire was sent to 503 schools which applied for help to the combined total of about ten million pounds.The answers to the question- naires provided valuable information about the volume of science being taught at elementary and advanced levels and gave some indication of the 217 position of science teaching in the schools. The Committee of the Fund decided that first priority of consideration should be given to schools with 250 or more pupils over the age of 13 of whom at least 10% were in the mathematical and science VIth forms and further since the main objective was to increase the number of chemists physicists mathematicians and geologists the claims of biology could not be considered except as part of general science teaching up to the Ordinary level in the General Certificate of Education.Later it proved to be possible to extend help to a number of schools with less than 250 pupils over the age of 13 which showed considerable promise and potential. Valuable as the information provided by schools was it could only form the basis for a preliminary sorting out. Four Assessors were therefore appointed to visit all the schools which on paper appeared to have a prima facie case. More than 230 schools were visited ;and in every case there were detailed discussions between the Assessor and the Headmaster as well as meetings with members of the science staff and visits to the science rooms. Almost invariably it trans- pired that the numbers of pupils who were specialising in physics chemistry and mathe- matics had been steadily increasing for some time and the demand showed every sign of in- creasing.Parents too appeared to be more interested in the possibilities of science both from an educational and from a careers point of view than they had ever been. In some schools with a well-established classical tradition the effects of the trend towards science were already being reflected in the increased number of boys who wanted to take up science seriously and in most of the schools which had already gained some reputation for science teaching the pressure of increased numbers was becoming acute. So much so that it was by no means rare to find that the number of boys who were allowed to con- tinue with physics and chemistry into the Sixth form had to be strictly rationed for lack of suit- able teaching space.In general school science rooms were designed years ago for numbers which have since been outstripped. Not only that but biology has rightly come into a far more prominent place than it held at the begin- ning of the century with the result that some science rooms-originally built for physics and PROCEEDINGS chemistry-now have other claims on them. Other consequences of the increased demands made on science teaching have been that in some schools ordinary classrooms offering no facilities for the teaching of science have had to be used for this subject and that the time spent on practical work in the laboratory has fallen below a reasonable limit.True with expert teaching examination results can be achieved but at what a cost when they are gained at the expense of adequate first-hand practical experience! Only too often one found that large classes had to be taken in laboratories which were too small for them. There was a general shortage of labora- tories for advanced work and frequently apparatus set up had to be dismantled after a Sixth-form class in physics or chemistry because the laboratory would be occupied almost im- mediately after the lesson by a large junior form. School laboratories vary between wide limits in quantity and quality. There are some examples of uneconomic planning with out-sized desks unnecessarily wide passages and excessive total floor space; there are relics of the days when the combined laboratory-lecture room was thought to be the last word in planning; there are old stables wooden huts and dark cellars which have been converted into laboratories; there are laboratories which are very good in quality but inadequate in number and variety.A great deal of ingenuity has been shown by Headmasters and science staffs to make the most of limited accommodation-but there are limits beyond which new building becomes a necessity. Some schools had already reached this stage and had begun to build new science rooms before the Fund came into existence. Most of the schools visited were handicapped to a smaller or greater extent by under-provision of ancillary rooms such as preparation rooms balance rooms and dark rooms.Nor was the supply of apparatus usually adequate for the work being done at different levels. But there were some stimulating examples of “self help” in the form of home-made apparatus. No doubt there would be even further development on these lines if science masters couId normally count on the services of a laboratory assistant. In order to help schools in the planning of new science accommodation realistically and eco-nomically a brochure on “Planning of Science AUGUST1957 Laboratories in Schools” was prepared by the Fund. In addition to detailed information about the designing of school laboratories it included suggestions for the sizes of rooms for elementary laboratories advanced laboratories demonstra- tion or lecture rooms and ancillary rooms.These suggestions were based on the fundamental assumption that an elementary class should not exceed 30 and that an advanced class should not normally exceed 15. Cost standards were also worked out in conjunction with the Ministry of Education and on these standards the Fund based the amount of grant offered to a school. In practice these standards proved to be gene- rally acceptable. The proposals put forward by schools took many forms. In a few extreme cases the real need was to build a new science block to replace existing unsatisfactory rooms but the most usual need was for additional laboratories demonstration rooms or ancillary accommoda- tion or combinations of these to provide extra space needed.Frequently it transpired that by some re-orientation and modernising of existing rooms with or without the provision of new buildings the most effective results could be obtained. Before reaching their final form pro- posals were discussed in detail at the school by the Headmaster and the Assessor and were frequently modified in the light of these discus- sions. Once the Committee of the Fund had decided in principle in the light of all the avail- able evidence to assist a school with a definite project the school representatives were invited to meet a sub-committee of the Fund and at that meeting a firmoffer was made. The amount of grant varied from one-half to two-thirds of the estimated cost of the project on the Fund’s cost and space standards provided the school guaranteed to find the balance.The need for speedy action was invariably stressed. Girls’ schools were assessed on the same standards as boys’ schools. With one or two exceptions they have not yet developed the teaching of the pure sciences to anything like the same extent as have boys’ schools This may be attributed partly to the difficulty of attracting science teachers of good quality; partly to the traditional claims of biology in a girls’ school; and to no small extent to the uncertainty that still exists in the minds of many Headmistresses about openings in industry for girls of high ability beyond routine jobs. It is now eighteen months since the Fund came into being.Already 187 schools have been offered building grants and the total amount given or promised to schools for new buildings is about &2,500,000. In the near future another six to ten schools will be assisted. A further 2361,250 is being given to all the schools which have building grants and to 143 other schools for the purchase of non-consumable equipment (apparatus). 82 girls’ schools will receive building grants or equipment grants. All this represents a remarkable achievement. The essence of the whole operation has been speed and thorough- ness. One may well surmise what will be the out-come of this enlightened venture. One thing is certain. By the help of the Fund the available science teaching space in the Independent and Direct Grant schools assisted will increase by 50% and conditions under which science will be taught in future will be vastly improved.If all the extra accommodation is used by pupils in excess of present numbers it would mean that over 4,000 more boys and girls can be catered for in physics and chemistry at Sixth-form level. Against this is the fact that some of the extra accommodation will be needed to improve con- ditions for existing pupils but all the evidence indicates that over the period of a few years a target of 3,000 more boys and girls studying advanced physics and chemistry can reasonably be expected to be reached and a substantial contribution will have been made to the nation’s pool of scientists.It is certain that schools have been encouraged and stimulated by the positive action taken by the Fund. Headmasters and Headmistresses are alive to the field which has been opened up and they are determined to make the most of a unique opportunity. PROCEEDINGS Application of Acidity Functions to the Mechanisms of Acid-catalyzed Reactions* By F. A. LONG (CORNELL ITHACA, UNIVERSITY NEWYORK) ALTHOUGH the concept of acidity functions was introduced by Hammett and Deyrup1v2 almost twenty-five years ago it continues to be the subject of a sizeable body of research. This is doubtless partly due to a continuing interest in acidity includ- ing an increased realization that there is room for a variety of definitions of acids.An equally important reason however involves the application of acidity functions to the problem of mechanisms of acid catalysis. It is the latter topic which I want particu- larly to consider now. The acidity function h is defined by h = KBH+.&+ ..................... .(1) CB where KBH+is the thermodynamic acid-ionization constant for aqueous solutions of an indicator which is uncharged in its basic form B and CBH+/CB is the experimentally determined indicator ratio. This definition is equivalent to h =CH+ .f,tf,....................... .(2) fBH+ where C,+ is the molar concentration of hydrogen ion and the activity coefficients f,+ etc. are referred to the value unity for the ideal dilute aqueous solu- tion. It follows that for a dilute solution of a strong acid in water h is simply equal to the stoicheiometric molarity.For more concentrated solutions these two measures of acidity will generally differ and from equation (2) one can think of the departure of h from CH+as due to “salt effects” on the activity coefficient ratio fH+fB/fB,+. A convenient logarithmic unit for the acidity function is H, defined by H = -log h,. As equation (1) indicates measurement of h in-volves a once-for-all determination of the ionization constant KBH+for aqueous solutions of a given in- dicator and then experimental measurements of the indicator ratio for various solutions-possibly in-volving quite different solvents than water. Measure- ment of indicator ratios is en tirely straightforward but measurement of KBH+for indicators which are not significantly transformed into their conjugate acid in dilute aqueous solutions presents real difficulties.The method used by Hammett and his co-workers was to proceed in a stepwise fashion toward indicators for concentrated solutions starting with indicators which ionize considerably in dilute aqueous solutions. This is illustrated in Fig. 1 which gives data for indicator ratios in aqueous sulphuric acid. For the two most basic of the indicators (a) and (b) the values of KBH+can be determined by conventional methods The problem is how to obtain values for other indicators (c) (d),etc. 20 40 60 I I I 0 H.2504(wt -70) FIG.1. Ionization of indicators in aqueous sulphuric acid.(a)p-Nitroaniline; (6) o-nitroaniline;(c) 4-chloro-2-nitro-aniline; (d)4-nitrodiphenylamine. For the actual procedure it was first necessary to choose indicators so that there was always an overlap between the indicator ratio plots for each pair of indicators. Then from a logarithmic plot like Fig. 1 the pKB,+ value for a less basic indicator was ob-tained by adding to the pKBH+ value for the previous indicator the vertical separation between the parallel !og(C,,+/C,) plots. Thus in Fig. 1 p&,+ for the indicator (c) is greater than the value for (b) by the magnitude of the vertical distance labelled x. This procedure gives true values for the unknown ionization constants provided one assumes that equation (3) holds for the two indicators concerned.* Lecture given before the Chemical Society in London on February 28th 1957. Hammett and Deyrup J. Amer. Chem. Soc. 1932 54 2721. Hammett “Physical Organic Chemistry” McGraw Hill New York 1940 Ch. IX. AUGUST 1957 This seems to be a fairly good assumption for indicators of not too different size and structure when used in solvents with good ionizing ability. fc --f ......................... .(3) fCW+ fBH+ However it is clearly an extra-thermodynamic aSSUmptiOn and it is easy to ima@ne SitUatiOnS where it Will not hold. Hence we must conclude that the ffo acidity fUnCtiOn is not truly independent Of the choice of indicator and solvent and that in this sense it is only approximate. The important question then is over what range of variations of indicator structure and of solvent is the function useful? This question is not yet fully answered.However we do know that the h function is a useful and fairly general measure of acidity for solutions of the mineral acids in water. It is clearly less general for solvents of low dielectric constant but it still seems useful for such solvents as 1 :1 water-dioxan. For solutions of the strong mineral acids in water ho does not depart significantly from C, until con- centrations of almost one molar acid are attained. At higher concentrations the two functions become very different and values of h for the various strong acids also differ considerably. These points are illus- trated in Table 1 which includes data for a weak acid.3 state contains only the reactant and a proton whereas correlation of rate with CH+indicates a reaction for which the transition state additionally contains a water molecule.In recent years this Zucker-Hammett hypothesis has been subjected to several critical tests and correlations of rate with both CH+ and h acidity have been investigated for increasingly wider ranges of conditions. The problems involved in rate-acidity correlations can be illustrated by considering two plausible alter- native mechanisms for the acid-catalyzed hydrolysis ofa neutral substrate. the terminology of Professor Ingold5 these mechanisms are labelled A-1 and A-2. A-1 S + H+ + SH+ Equil. SH+-+X+ + Y Slow X+ + H20 = Products + H+ Fast A-2 S + H+ =$ SH+ Equil.SH+ + H20-+ Products + H+ Slow Both involve preliminary equilibrium protonation of the substrate. They differ in the details of the slow step which is a unimolecular reaction for the A-1 mechanism but for the A-2 mechanism is a bimolecular reaction with water. The Zucker-Hammett hypothesis predicts that the rate of A-1 reactions should correlate with h and that the rate for A-2 reactions should correlate with CH+.An interesting point is to what extent can these predic- tions be justified by a priori arguments? TABLE1. Values of h C, (mole/l.) HCIOl HCl HNO H3PO4 0.1 0.11 0.1 1 0.11 0.045 1.0 1.6 1.6 3.0 17.0 11.2 6.0 690 132 10.0 620,000 4800 Given the large differences between h and the molar concentration of hydrogen ions which enter at the higher concentrations an obvious question to ask is whether there are groups of acid-catalyzed reactions the kinetics of which follow one or the other of these functions.If the answer is yes the obvious next question would be whether this result is a consequence of different mechanisms for the reactions. Both of these items were investigated very Soon after the development of the h acidity scale. Examples were found of reactions where rate closely paralleled h and of others where rate closely paralleled CH+.In 1939 Zucker and Hammett4 sug- gested that this reflected a difference in mechanism. Their particular proposal was that correlation of rate and h indicates a reaction in which the transition 1.6 0.23 10.5 1.2 62 11 -390 The rate for an A-1 reaction is given by Rate = k,C = k,C,C,+ &fH+ = k2OC,CH+.-fM* where kzO is a true constant and where fM* is the activity Coefficient for the transition State Of the reaction.SOhtiOn for k and then substitution for CH+by equation (2)leads to kl = kzoh0.&&+ ................... .(4) fM*fB In other words the experimental first-order rate coefficient k will vary directly with h if the activity The h values of this Table are taken from a recent compilation (Paul and Long Chem. Rev. 1957 57 1) and are referred to a value of ~KBH+ = 0.99 for p-nitroaniline. * Zucker and Hammett J. Amer. Chem. Soc. 1939 61 2791.C. K. Ingold “Structure and Mechanism in Organic Chemistry,” Cornell University Press Ithaca N.Y. ,1953. coefficient ratio &f,* varies with the medium in the same way as does the ratio fB/fB,+ for a Hammett indicator and its conjugate acid. For the A-1 mechan-ism the transition state is simply the conjugate acid of S with its bonds loosened. Hence the proposed correlation of rate with h is quite plausible. Even so this argument is clearly not a proof. For the A-2 mechanism the analogous equations are Rate = k,C = k,C,C,+ Here the first-order rate coefficient will be given by k = k20C,+f,fH+an*0 ... . . . . . . . . . . . . . . .(5) fM* For a direct correlation of rate with C,+ the activity coefficient ratio of equation (5) must remain essentially constant with changes in the medium.(mole/l.) (1.mole-l sec.-l) Glycerol monoanisate 0.043 0.04 0.042 0.98 0-47 0.47 0-45 0.95 1.94 4.3 1.57 0.8 1 3.84 33.0 3.32 0.86 5.74 360.0 5-54 0.90 This is very difficult to justify a priori. As a result it is hard to avoid the conclusion that the only signifi- cant justification for use of the Zucker-Hammett hypothesis with either A-1 or A-2 mechanisms will be the experimental one that it gives the correct answer for reactions whose mechanisms are firmly estab- lished by other evidence. Let us then consider the experimental results for some acid-catalyzed reac- tions of known mechanism. A reaction which quite surely follows the A-2 path is the acid-catalyzed hydrolysis of ordinary carboxyl- ate esters.The evidence for this is well summarized in reference works on physical-organic chemistry6 and need not be repeated here. In agreement with the Zucker-Hammett hypothesis there is now a large body of data for this reaction to show that the hydrolysis rate correlates with concentration of hydrogen ion rather than with h,. This has been ' See for example ref. 5 Ch. XIV. PROCEEDINGS shown for example to be true for the hydrolysis of the aliphatic esters methyl formate and ethyl acetate in solutions of up to ten molar in aqueous hydro- chloric acid. Actually for both of these esters the rate increases somewhat faster than linearly with molar concentration of acid. Even so the rate correlates much more closely with C, than with h,.' For esters of substituted benzoic acids the correlation of rate and molar concentration is very close as the data of Table 2 show.* A similar close correlation has been found for the hydrolysis of ordinary y-lactones9 and these are essentially inner esters.These results suggest that the Zucker-Hammett hypothesis offers a useful criterion for the A-2 mechanism. Results for still other A-2 reactions are in accord with this con- clusion but rather than give further examples let me turn to a consideration of the A-1 reaction. The acid-catalyzed hydrolysis of acetals and ketals fairly surely follows the A-1 mechanismlo and data on the rate of hydrolysis of a typical acetal are given in Fig.2.11Quite evidently the rate at high concentra- tions of acid correlates closely with the h acidity and (mole/l.) (l.mole-' sec.-l) Methyl benzoate 0.98 1.3 1.87 1.91 1.93 4.3 3.66 1*90 3.82 32.0 7.45 1.95 ~ very poorly with molar concentration. This is in accord with the Zucker-Hammett hypothesis and provides additional evidence for it. Similar behaviour has been found for still other aqueous reactions which fairly surely follow the A-1 mechanism. Hence the utility of the Zucker-Hammett hypothesis for A-1 reactions also seems fairly well established. Actually the correlation of Fig. 2 is not exact since the slope of the plot of log k against -H is 1.15 rather than the value of unity which is expected from equation (4).Evidence of specific effects is provided by the somewhat higher slope of a line through the points for hydrochloric acid as compared for example with those for perchloric acid. A departure from unity for the slope of the plot of log k against -Ho is of course worrisome since it can evidently complicate conclusions about mechanisms. But in view of our earlier discussion this departure is not Bell Dowding and Noble J. 1955 3106. * Chmiel and Long J. Amer. Chem. SOC.,1956,78 3326. Long McDevit and Dunkle J. Phys. Colloid Chem. 1951 55 813. lo Ref. 5 Ch. VII. McIntyre and Long J. Amer. Chem. SOC.,1954,76 3240. AUGUST 1957 223 particularly surprising. In terms of activity co-efficients it means that equation (6) is only approxi- mate f, --f* ... . ......... . ........ . .....(6) fM* -fBIi+ Some of the difficulty might arise from the fact that M* does not quite behave as the conjugate acid of S. However another possibility is that the approximate nature of equation (6) is simply a result of the approximate nature of the h function itself which Steric hindrance from the ortho-substituents should slow down the A-2 hydrolysis whereas added electron release in the acid moiety should aid an ionizing mechanism. The possible A-1 mechanism is R’C0,R + H+ +R’C02RH+ Equil. R’C02RH+ -+ R’CO+ + ROH Slow R‘CO+ + H20 = R’C0,H + H+ Fast With mesitoic acid the acylium ion R’CO,+ is known to be stable in pure sulphuric acid (where hydrolysis is instantaneous).The only question is whether it 4 3 0 + :2 I I I 0 7-0 2.0 ‘HO FIG.2. Hydrolysis of methylal at 25”. The broken line is predicted for a rate proportional to CH+. as we noted arises from the rather similar assump- tion of equation (3). This sort of assumption may in fact be poorer for the kinetic correlations than for the acidity function itself since the reactant involved will usually be structurally quite different from a typical Hammett indicator. From this standpoint we can safely predict that slopes of the plots of log k against -H will frequently depart slightly from unity even for reactions which follow the A-1 mechanism. I should like next to consider some cases of rate-acidity correlations for reactions whose mechanisms are less firmly established and for which the Zucker- Hammett hypothesis may give additional inforrna- tion.For one example let me return to the acid- catalyzed hydrolysis of esters. Even though the A-2 mechanism is the normal one it is known that an A-1 mechanism is a good possibility for certain classes of esters. One such class is esters of 2 :4 :6-trimethyl-benzoic acid. l2 See ref. 8. 3 d f ‘I a’ UT 0 7 2 3 -Ho FIG.3. Hydrolysis of esters in aqueous acids at 90”. Methyl mesitoate log kl + -7 for perchloric acid 0; log k + 7 for sulphuric acid 0.Glycerol 1-benzoate log kl + 4.5 for perchloric acid 0. enters as a kinetic intermediate at the much lower acidities where rates are slow enough to be measur- able.The data (Fig. 3) show that a good although not exact correlation between rate and h exists.12 Comparison of the results with those for glycerol 1-benzoate whose rate closely follows molar concen- trations of hydrogen ion emphasises the different behaviour of the mesitoate and benzoate esters. From the Zucker-Hammett hypothesis one would con-clude that a water molecule does not enter into the transition state for the reaction of methyl mesitoate and in this sense the data support the proposed A-1 mechanism. A rather different type of reaction is exemplified by the acid-catalyzed depolymerization of the cyclic trimers of aldehydes. This differs from the previous reactions in that it is a simple decomposition rather than a hydrolysis.Since a water molecule is not essential to the process an A-1 mechanism is a fairly obvious possibility. The reaction has been studied for the trimers of f~rmaldehydel~-~~ and acetalde- hyde,16 and in both cases an excellent correlation of rate and h has been found. Fig. 4 illustrates this with some of the older data for the depolymerization of trioxan. These results may not suffice to establish the reaction path definitely but they clearly are support for an A-1 mechanism. One of the interesting items of Fig. 4 is the position of the two solid points. These are for rate studies in anhydrous acetic acid containing some sulphuric acid. They illustrate one of the more important pro- perties of the h acidity scale which is that it can be applied without difficulty to studies with mixed water-organic solvents and also with anhydrous solvents.Data on h acidities for solutions in several such solvents are in fact available? However in view -71 I I I I 1 +I 0 -I -2 -3 -4 ff FIG.4. Depolymerization of trioxan in aqueous solutions of acids at 40" except that solid points are for solutions of sulphuric acid in glacial acetic acid. of the previously discussed approximate character of the acidity function we must ask whether for these solvents the values of h are sufficiently independent of choice of indicator to be useful. This question is only partially answered but the tentative indications are that for solutions of quite low dielectric constant e.g. anhydrous dioxan or ethanol the function may not be very useful but that acidity scales of adequate generality can be developed for water-organic solvent mixtures of fairly high dielectric constant.Suppose one has a reaction whose rate in aqueous solution correlates with h and which can also be PROCEEDINGS studied in other solvents. It is then of considerable interest to see if the rate of the reaction in the various solvents is determined solely by the k acidity. The solid points of Fig. 4 show that for the reaction of trioxan the rate at a given h is approximately the same for the solvents water and acetic acid although not precisely so. Another comparison has recently been made with these same two solvents by SatchelP' for the acid-catalyzed hydrogen-isotope exchange of anisoles; for this case also the rates in the two solvents at a given value of h are very similar.A rather different solvent system for which h values are well established is anhydrous and nearly anhydrous sulphuric acid. The kinetics of several decomposition reactions have been studied in this solvent and some excellent correlations of rate and ,>S/ope =0.85 I / L I I I I 7 3 5 7 9 -Ho FIG. 5. Decarboxlylation of mesitoic acid in aqueous acids at 90".H2S04 0and v; HC104 a;HCl 0; HsP04 A. h have been observed. However the mechanistic significance of these correlations is by no means certain. The A-1 mechanism is an obvious possibility for this solvent and may well be the normal path for decompositions.In contrast the behaviour with changing acidity of an A-2 (or related) mechanism is not known for this solvent; hence a rate-acidity correlation does not as yet permit a distinction among mechanisms. A type of reaction which has been studied in a wide range of solutions of sulphuric acid is the elimination reaction of hindered aromatic acids and aldehydes. The loss of carbon dioxide from mesitoic acid is an example and Fig. 5 gives data.18-20 A l3 Walker and Chadwick Ind. Eng. Chem. 1947 39 974. l4 Paul J. Amer. Chem. Soc. 1950 72 3818; 1952,74 141. l6 Bell Bascombe and McCoubrey J. 1956 1286. Bell and Brown J. 1954 774. l7 Satchell J. 1956 3911. Schubert J. Amer. Chem. SOC.,1949,71 2639. l9 Beringer and Sands ibid. 1953,75 3319.2o Long and Varker unpublished results. AUGUST1957 conceivable mechanism is the A-1 for which the rate-determining step would be loss of carbon dioxide from the conjugate acid. The observed dependence of rate on h at the lower acidities is consistent with an A-1 mechanism. So in fact is the departure from linearity which occurs in Fig. 5 at at an H value of about -6. The explanation of this last statement is that a linear plot of log kl against -H, is expected only if the amount of conjugate acid present is relatively very small i.e. if it is a kinetic intermediate. For the general case the correlation equation is log k = -If -log 1 + 0+ constant ( Hence when the h acidity becomes comparable to K,, the initially linear plot of log k against H should begin to curve.For mesitoic acid pK,, is -7.4 at room temperature.21 It being assumed that a value close to this is valid at go" the levelling off of the plot of Fig. 5 occurs at about the expected acidity. If one ignores (or otherwise explains) the sizeable decrease in rate which occurs for still higher acidities one might easily conclude that Fig. 5 sup-ports an A-1 mechanism. However Schubert and his co-workers as a result of an extensive study of this and related reactions have rejected the A-l mechan-ism in favour of a somewhat more complex one which involves among other things general acid-base catalysis in concentrated solutions of sulphuric The fact that a given set of kinetic data may be consistent with more than one mechanism is of course not very surprising but in the present case it does lead me to make a few cautionary remarks on the application of acidity functions to problems of mechanism.What we clearly desire is to use rate-acidity correlations in a predictive sense i.e. to use them as evidence for particular mechanisms. Now of course this is actually being done and will doubtless con- tinue to be done. I only want to emphasize that there are two implicit dangers which should cause us to use this criterion with some caution. One danger stems from the fact that the real basis for the use of h (in distinguishing for example between A-1 and A-2 mechanisms) is an experimental one. Hence there is a distinct possibility that contradictory results may be discovered.As an example a reaction may be found which from other evidence belongs to the A-2 class but which actually shows a correlation of rate with h instead of with concentrations of hydrogen ion. One or two such contradictions will greatly lower our confidence in the predictive use of correlations. Another perhaps equally serious danger is that we may not really consider all relevant mechanisms. It is clearly possible (and this was the point of the discussion of mechanisms for the elimination reactions) that in addition to the A-1 some quite other mechanism-all it Y-may also lead to a rate-h correlation. Similarly other mechanisms than A-2 may lead to rate-C, correla-tions. Hence a given correlation may only point to a group of mechanisms rather than to a single one.Actually this is not a very surprising conclusion since few if any criteria for mechanisms lead to unique answers. And I do think that even the few examples which have been considered show that in spite of these worries comparison of rates with acidity functions constitutes an exceedingly useful tool for mechanism studies. As a final point let me emphasize that this discus- sion has dealt with applications of only one of the several available acidity functions. The functions h and h-have been defined by equations very similar to (1) and (2) for indicators which in the basic form are positively or negatively charged. Both of these have been applied to problems of mechanism.There is also a most interesting J function which has been defined for a rather different type of ionization process the reaction of a carbinol with an acid to give a carbonium ion and water and which therefore can serve as a criterion for a distinctly different class of mechanisms for acid-catalysis. 21 Schubert Donohue and Gardncr J. Amer. Chem. Suc. 1954,76 9. 2* See for example Schubert and Burkett ibid. 1956 78 64. PROCEEDINGS THE CHEMICAL SOCIETY LIBRARY INFORMATION and documentation are terms which occur frequently in current scientific literature and it is scarcely necessary to remind chemists of the value of a library as a source of such information. Yet although the Society membership numbers some 9,OOO only about 1,200 are registered as users of the Library.It may be that many of the others have university or industrial libraries able to meet their needs but the following notes are written for those who are not fully aware of what the Chemical Society Library does and can do for the chemist. The history of the Library is almost that of the Society its formation was one of the original objects of the Society on its foundation in 1841. At first a single bookstack sufficed to hold all the books but by the end of the century the stock had entered five figures and by the end of the First World War had grown to 25,000 volumes. The importance of the Library as a national centre for information on chemical subjects was established during the 1914-18 war when considerable use was made of the Library by the War Office and other Government departments.The Library then con- tained a great deal of information that could not be found anywhere else in the country. It was largely because of this heavy wartime demand that the Chemical Society called a conference of Societies interested in chemistry out of which resulted in 1919 an agreement by which the Chemical Society became the joint Library of nine different Societies. The other Societies were thereby relieved of the heavy expenses of running such a Library and instead gave financial support to the Chemical Society Library which was so enabled to cover the entire field of chemistry. Between the wars the Library expanded rapidly and shelf space was the continual headache of the Librarian.Many schemes were put forward to in- crease accommodation-even going so far as to propose turning the meeting room into a library bookstack! Wall after wall of the Society’s rooms became covered from top to bottom with book- shelves until by the middle of the Second World War there remained no further space capable of housing books. Books on many shelves were stacked two deep books were stacked quite inaccessibly in a loft books enclosed the Librarian’s desk. Books were everywhere! yet despite this terrible congestion the library continued to render reasonable service throughout the Second World War when once again it became a frequent source of information for the G ovemment services.The Library survived the war with its stock intact and in common with most libraries found that it began to expand even faster than before as the war- time lag in research and publication began to be made up. So critical had the space situation become that the advice of an outside consultant was sought. His report suggested one main theme-to find new storage space outside Burlington House and to prune the stock. Acting on this the Society obtained the lease of a large basement in Savile Row which was converted into a book store. Simultaneously additional office space became available in the same building and the administrative and editorial depart- ments of the Society were accommodated therein. The effect of this was to enable a very large move- ment of books to be made within Burlington House to give better deployment of the stock.The stock was thoroughly overhauled and a great deal of redundant material disposed of as recent Library Reports show. The opportunity was also taken of refurnishing the Library. For the moment the Library has sufficient elbow room but the present arrangement is far from ideal since the reader has ready access to only a small fraction of the stock and this disproportion will steadily grow. The Library serves the chemist in a number of ways the most obvious being that of supplying books and periodicals on loan. This is the most heavily used service of the Library and a considerable volume of the work is done by post. The Library has always prided itself on prompt service and in general a request will be dealt with on the day of receipt.In recent years the photocopy service has been increasingly used and now runs a close second to the loan service. New equipment has recently been installed capable of producing either 35 mm. micro-film or positive prints and the volume of work is such as to require almost the whole-time attention of one assistant. Here again the service is speedier than most other sources and every effort is made to trans- mit the copies within three to four days of receipt of the order. Readers are coming to prefer this service since it frequently costs very little more to have a copy made than to have a heavy volume of a periodical sent by post. The number of readers using the Library as a source of reference remains steady although so large a proportion of the stock can be seen only on applica- tion to the staff.This is probably because the very smallness of the premises enables a volume to be fetched very quickly and even from the Savile Row store books can be obtained in fifteen minutes or AUGUST1957 227 less which is substantially better than many other major libraries can claim. Nor must it be forgotten that the Library is of immense value to the Editors in the production of the Society’s publications. In fact Current Chemical Papers could not appear at all if it did not have the supply of some five hundred journals taken by the Library upon which to draw for its information.The Library also acts as an information bureau. The staff are essentially librarians not chemists and so are not able to seek out the minutiae of chemical information which require an intimate knowledge of chemical structure and reaction. They can and will readily provide that information that is available from reference works and by picking the brains of their chemically qualified colleagues of the editorial staff they frequently succeed in tracking down the more abstruse enquiry. The Library adds to its stock some two to three hundred textbooks and five to six hundred volumes of periodicals each year. It is because of the wide range of foreign books and periodicals that the Library has been so highly valued by Government departments in war time since this Library has fre- quently been the sole source in the country of some of the less-known works.The books are added after careful consideration by the specialists serving the Library Committee-which represents all the associated societies-or on the advice of accepted authorities. The Library does not purport to hold all works published on chemistry-it would never have room to house them-and so excludes minor works and such student’s textbooks as may reasonably be expected to be held by the student himself. Never- theless it is regarded both at home and abroad as one of the great chemical libraries of the world. RECENT ADVANCES IN THE CHEMISTRY OF TERPENQID COMPOUNDS (REPORT OF A CHEMICAL SOCIETY SYMPOSIUM HELD IN GLASGOW ON JULY11TH AND 12TH 1957) AT this Symposium seventeen papers were read by a distinguished company which included visitors from Czechoslovakia France Sweden Switzerland and the United States.The proceedings were opened by the President Professor E. L. Hirst who welcomed visitors to Glasgow on behalf of the Society. He then presented the Flintoff Medal to Professor H. Erdtman (Stockholm) for his distinguished work on the study of the relations between chemistry and botany. In the first session which was devoted to sesquiter- penoids Professor Sir Ian Heilbron occupied the Chair. Professor A. J. Birch (Manchester) was the first speaker and described work carried out with Drs. D. J. Collins R. P. Hildebrand A. R. Penfold and M.D. Sutherland in Manchester Sydney and Queensland on “Zierone a derivative of a new natural azulene zierazulene (2:4-dimethyl-8-iso-propylazulene)”. The structure of the latter was rigidly established by synthesis and with reservations as to the interpretation of certain reactions a full structural proposal for zierone was presented. The second speaker was Professor W. Cocker (Trinity College Dublin) who described the remark- able transformation induced by “Irradiation of the santonins in aqueous solution” that is as the potassium salt. The product from cc-santonin lumisantoninic acid was converted by diazomethane into the corresponding lactone lumisantonin which was isomeric with santonin. In the formation of lumisantoninic acid the cross-conjugated dienone system characteristic of santonin was destroyed with the formation of a perhydroazulene structure.This furthermore was believed to contain a cyclupropane ring conjugated with the remaining ketonic function. Amongst much other work it was shown that treatment of lumisantonin with boron trifluoride in acetic acid gave the known acetate of isophotosantonic lactone. A structure for lumisan- toninic acid was suggested and it was pointed out that a similar transformation occurred with p-santonin. In the course of the subsequent discussion Professor D. H. R. Barton (Glasgow) and Professor 0.Jeger (E. T. H. Zurich) revealed that independent work in their laboratories on what was very possibly a substance identical with lumisantonin led to a different structure Professor F.iorm (Institute of Organic Chemistry Prague) discussed the structures of three sesquiter- penoids ; carotol laserpitin and acorone together with related compounds. Apart from their chemical interest these substances like zierone present an additional biogenetic problem. Carotol and laserpitin have been shown to have the constituent isoprene units arranged in an irregular (i.e. non-farnesol) manner and in fact are derivatives of 1 :7-dimethyl-4-isopropylnaphthalene(isucadalene). It might previously have been supposed that the non-farnesol structure of carotol and its cogentrs PROCEEDINGS could have been due to methyl migration at some stage of their genesis. The reasonable suggestion now made was that carbocyclic spirans of the acorone type were in fact the intermediates responsi- ble since by ring expansion in alternative ways either the cadalene or the isocadalene type of structure could be produced.It was particularly opportune that in the discussion Professor Erdtman was able to announce the discovery of a new sesquiterpenoid spiran widdrol. The final subject of the morning session was that of the “Oxidation of sesquiterpenes of the eudesmane series and related compounds” and was presented by Dr. F. J. McQuillin (King’s College Newcastle). In this paper some experiments on the conversion of cyperone derivatives into acids related to the santonins were described. Of particular interest was the account of base-catalysed autoxidation in this series resulting in the introduc- tion of a hydroxyl group in the y-position of c$-unsaturated ketones and of the influence of the orientation of the isopropyl side chain.Examples were given of hydroxylation with alkaline per- sulphate. In the afternoon session Professor J. Read (St. Andrews) was in the Chair and the first speaker was Professor E. R. H. Jones (Oxford) who described work carried out with Drs. T. G. Halsall W. J. Dunstan and H. Fazakerley. The subject was “The chemistry of hydroxyhopanone” the latter being a saturated pentacyclic hydroxy-ketone of the triter- penoid series. It was shown to contain a terminal six-membered ring of the type common as ring A of the triterpenoids with a ketonic function at Co).The remaining oxygen function in the molecule a tertiary hydroxyl group was shown to be on an isopropyl group attached to a five-membered ring. With the aid of biogenetic considerations some general structural proposals were made and in the following discussion Professor Barton pointed out the general similarity between these proposals and those entertained by his group for the lichen triter- penoid zeorin. Professor Jones was followed by Dr. G. Ourkson (Institut de Chimie Strasbourg) who described some of the “Chemistry of Dipterocarpus terpenes”. In this work carried out with Drs. P. CrabbC and T. Takahashiand Mr. M. Palmade both sesquiter- pene and triterpenoid fractions were reported as being present in the oleoresin obtained from four species.The sesquiterpene fractions consists of the previously known a-and /3-gurjunenes separable however only with difficulty. In the present case the or-isomer was obtained pure for the first time and was believed to be a guaiadiene. The triter- penoid fraction dipterocarpol was shown to be identical with a tetracyclic compound hydroxy- dammarenone-11 previously isolated by Mills and Werner together with the already mentioned hydroxyhopanone from dammar resin. An account was given of work directed towards the elucidation of the stereochemistry of this substance. Dr. F. E. King (British Celanese Ltd.) presented the evidence which had led him and Dr. J. W. W. Morgan to the elucidation of the structure of “Katonic acid a new triterpene from Sandoricurn indicum”.This substance 3a-hydroxyolean- 12-en- 29-oic acid was converted into p-amyrene into epi-/3-amyrin and by introduction of the dienedione system characteristic of the /3-amyrin series with selenium dioxide into the demethyl-/3-amyradiene- dione identical with that obtained from methyl 1 1-deoxoglycyrrhetate acetate. The final paper in the afternoon session “Terpenoids and conifer taxonomy” was presented by Professor H. Erdtman (Royal Institute of Technology Stockholm). Many of the dangers and pitfalls of chemical taxonomy were pointed out. In particular it was stressed that the presence or absence of merely one particular compound in a series constituted insufficient evidence for taxonomic deductions; rather the general pattern of substances should be considered.Furthermore compounds selected as “tracers” should not be too widely distributed as is for instance pinene in conifers but should be more limited. Examples were pre- sented of such “tracers” in the terpenoid field and the limitation of the method was outlined. The im- portance of this study was sketched against the greater evolutionary background its advantage being that chemical substances are more readily identified than are say morphological characteristics. At the conclusion of the meeting on Thursday transportation was made available to the Forest Hills Hotel at Aberfoyle where a dinner designed to exhibit the gastronomic amenities of Scotland was enjoyed.A toast of the Chemical Society was delightfully proposed by Professor Erdtman to which the President Professor Hirst replied. The third session was held on Friday morning with Professor E. R. H. Jones (Oxford) in the Chair. The first paper entitled “Synthesis of tricyclic diterpenes” was given by Professor E. Wenkert (Iowa State College) and described work done in collaboration with Dr. B. G. Jackson. The degra- dation of derivatives of podocarpic and dehydroabi- etic acids to derivatives suitable as “relays” for synthesis of diterpenes of the resin acid type was studied. In particular application of the Kenner phosphate procedure to methyl podocarpate proved successful and has been shown to afford a general method for hydrolysis of highly hindered esters.The AUGUST 1957 deisopropylation of dehydroabietonitrile was des-cribed and the mechanism lucidly discussed. The problem of the nature of diterpene biogenesis was outlined and in the ensuing discussion contributions were made by Professors Birch Cristol and New- man and Dr. Todd. This was followed by a paper by Dr. T. G. Halsall (Oxford) on “Some aspects of the chemistry of iabdanolic acid” (with Dr. J. D. Cocker). The elucidation of the structure and stereochemistry of labdanolic acid obtained from gum labdanum and its degradation to a known ambrein degradation product were described. The striking but incomplete correlation with eperuic acid was pointed out. It has been recently established that there is a qualitative but not quantitative mirror-image relation in the rotary-dispersion curves of suitable derivatives of the two acids and the probabilky that the acids are mirror images as far as the A/B ring junctions are concerned was suggested.Dr. Halsall pointed out that diterpenes and triterpenes do not appear to occur together and discussed the significance of this in terms of biogenesis. Alternative views were forwarded by Professor Wenkert involving the role of the enzyme in cyclisation. In the third paper entitled “Synthetic approaches to iridodial” Professor R. A. Raphael (Belfast) indicated the known structures of iridodial iridolac- tone iridomyrmecin and nepe tolactone all of which have a cyclopentane system and showed how they had been related to nepetolenic acid.He out- lined an elegant projected synthesis of iridodial starting from pyrogallol and acetoacetic ester and reported the considerable progress towards its realisation. The problems of stereospecific control were described and in the following discussion the use of ruthenium oxide as a hydrogenation catalyst was mentioned and doubts were expressed concern- ing the accepted stereochemistry of these naturally occurring compounds. The final paper of the morning session was given by Dr. W. B. Whalley (Liverpool) on work done with Miss Adelaide Harris and Professor Alexander Robertson on ‘‘ The structure of rosonolactone and rosenonolactone”. The functional groups of these metabolites obtained from the mycelium of Trichothecium roseum Link have been established by standard methods.Both possess vinyl groups and yield 1:7-dimethylphenanthrene on dehydro-genation. Structures were forwarded for degradation products from dihydroisorosenonolactone and the known facts were rationalised in terms of probable formulae for both lactones. The concluding session opened on Friday after- noon under the chairmanship of Professor A. J. Birch (Manchester). The first paper given by Dr. R. N. Jones (National Research Council of Canada) entitled “Recent developments in the interpretation of steroid infrared spectra” began with remarks on newer methods of experimental technique particu- larly for the handling of samples of less than fifty micrograms.The development of a more systematic approach to the interpretation of the “fingerprint” region of steroid spectra was outlined and it was pointed out that the major features of the characteris- tic zone absorptions in steroid monoalcohols and monoketones are easily observed by comparison with the spectra of the corresponding saturated hydrocarbons. In the discussion to which Dr. Page contributed the use of bromoform as a solvent for spectral use and the relative merits of nujol mulls and potassium bromide disks were mentioned. The following paper on “The structure of carvone camphor” was given by Professor G. Buchi (Massa- chusetts Institute of Technology) and described work done in collaboration with Mr. Goldman. The formation of this tricyclic ketone by sunlight irradiation of carvone had been described by Ciamician and Sernagiotto who proposed possible formulae.Professor Buchi described a series of experiments involving oxidation isomerisation and pyrolysis of carvone camphor which have now led to a unique structure The reaction mechanisms for the formation of the products from these experi- ments were completely rationalised and the radical mechanism of formation of carvone cam- phor was discussed. The third paper entitled “The chemistry of limonin” was given by Professor 0. Jeger (E. T. H. Zurich) and outlined work performed in collabora- tion with Drs. A. Melera and D. Arigoni and Mr. K. Schaffner on the constitution of the bitter principle isolated from Citrus seeds.The nature of all eight oxygen functions has been established with almost complete certainty; various degradation products have been obtained and their significance with regard to the constitution of limonin was discussed. The relation of limonin to the known limonilic and limonexic acids has been elucidated and was outlined. In discussion Professor Barton indicated that the chemistry of limonin was being studied in his laboratory and that an X-ray crystallo- graphic examination was 2lso in progress. “The structure of some minor alkaloids of Aconitum napellus” was dealt with in the penulti- mate paper by Professor K. Wiesner (University of New Brunswick). These alkaloids included napelline napellonine and isonapelline which have now been obtained in crystalline form.Dehydro-genation and acid-catalysed isomerisation pro-cedures were described and comparisons and con- trasts drawn with the behaviour of garryfoline veatchine and garryine. The tentative structures proposed were supported by the ultraviolet and infrared spectra of the napelline alkaloids and their derivatives. The concluding paper was given by Dr. R. C. Cookson (Birkbeck College) on "Delpheline". The work described carried out with Dr. M. E. Trevett has established the presence of a secondary hydroxyl group adjacent to a dioxymethylene ring. The nature of further functional groups has been demonstrated and the reactions of a triol obtained on hydrolysis of delpheline closely resemble those of the diter- penoid alkaloid lycoctonine and structures were proposed for delpheline and some degradation products on the assumption of an identical C-N skeleton.The desirability of unequivocally inter- relating delpheline and lycoctonine was stressed in discussion. In his concluding remarks Professor D. H. R. PROCEEDINGS Barton (Glasgow) speaking on behalf of the organis- ing committee thanked the chairmen and speakers for having contributed so largely to the success of the symposium and expressed appreciation for the financial support received from Glasgow University and the Chemical Society. He was certain that all members present would be particularly grateful to the Society's Local Representative Dr. D. S. Payne for his strenuous and successful efforts in arranging the symposium.On Friday evening there was enjoyed a lavish buffet supper provided through the kindness and courtesy of the Chairman and Directors of the Nobel Division of Imperial Chemical Industries Limited and the hospitality and entertainment of a flavour both Scottish and Scotch was greatly appreciated. P. de MAYO ROBERT STEVENSON COMMUNICATIONS The Purification of Sulphur Tetrafluoride By N. BARTLETT and P. L. ROBINSON NEWCASTLE (KING'SCOLLEGE UPON TYNE) INTEREST has been shown in the bonding in the tetrafluorides of sulphur and selenium and in the consequent shape of these mo1ecules.l As a result this laboratory has received several requests for samples. However the properties of sulphur tetra- fluoride preclude its transport except by hand and at -180"; it boils at -40.5" and the vapour attacks glass.The preparation described by Brown and Robinson2 is laborious since it involves separation of the compound from a crude product of the low- temperature fluorination of sulphur which contains among other volatile substances thionyl fluoride boiling at -43.8". This note describes a new and simple way of separating sulphur tetrafluoride from this difficult mixture and also the means of preparing directly an easily handleable solid from which sulphur tetrafluoride can be readily obtained. Recently Bartlett and Robinson3 showed that sulphur tetrafluoride forms solid co-ordination com- pounds with boron trifluoride and other acceptor molecules and furthermore that these molecules do not form complexes with substances containing sulphur and fluorine other than the tetrafluoride it- self.They have also found that the SF4*BF3 complex is produced directly when a mixture of boron and sulphur is fluorinated at -75" in a slow stream of fluorine well diluted with nitrogen. Clearly it only remained to find a way of releasing the sulphur tetra- fluoride from the complex and at the same time fixing the volatile boron trifluoride. This we find can be done by heating the solid with selenium tetrafluoride which enters the complex in place of the sulphur tetrafluoride. SF,*BF + SeF -f SeF4.BF + SF Starting from the crude tetrafluoride derived from the fluorination of sulphur the SF,*BF complex is made by condensing boron trifluoride on to the solid mixture allowing the temperature to rise and then pumping off the thionyl fluoride sulphur hexa- Bowen Nature 1953,172 171 ; Dodd and Woodward Trans.Faraday Soc. 1956,52 1052. Brown and Robinson J. 1955 3147. * Bartlett and Robinson Chem. and hd. 1956 1351. AUGUST 1957 fluoride and disulphur decafluoride. To recover sulphur tetrafluoride the SF,.BF3 complex (whether obtained in this way or prepared directly) is warmed with a deficiency of selenium tetrafluoride. The reac- tion appears to be quantitative and the product is pure sulphur tetrafluoride. In any case the two tetra- fluorides are easily separated by fractional distilla- tion.Incidentally selenium tetraAuoride4 is not difiicult to prepare and purify and can be kept in sealed glass tubes at ordinary temperature. Sulphur tetrafluoride can be displaced in the same 231 way from SF,.AsF and SF,*SbF, both involatile compounds easily stored at the ordinary temperature. Details of this and cognate work on the complexes of sulphur tetrafluoride will be published later. Acknowledgement is made to Imperial Chemical Industries Limited General Chemicals Division Widnes for the loan of the fluorine cell used and to Imperial Smelting Company Limited for a gift of boron trifluoride. (Received July 12th 1957.) * Dodd and Robinson "Experimental Inorganic Chemistry" Elsevier Amsterdam 1954 p. 219; Aynsley Peacock, and Robinson J.1952 1231. New Hydroperoxidesformed on Autoxidation of Hindered Phenols By A. F. BICKEL and H. R. GERSMANN [KONINKLIJKE/SHELL-LABORATORIUM, AMSTERDAM (N.V. DEBATAAFSCHE PETROLEUM MAATSCHAPPLJ)] THEoxidation of hindered phenols such as 2:6-di- tert.-butyl-4-methylphenol and 2 :4:6-tri-tert.-butyl-phenol has been often investigated. Oxidation with potassium ferricyanide or lead dioxide in alkaline media leads to the formation of phenoxy-radicals which according to the conditions undergo different reacti0ns.l Autoxidation of the dibutylphenol in alkaline media has been described only by Yohe et aL2 who worked at 100"; they isolated 3:5 -di-tert.-butyl-4-hydroxybenzaldehyde pivalic acid and possibly 2 :6-di-tert.-butyl-p-benzoquinone.It has now been found that in the alkaline autoxidation of both the named phenols at 25-40" hydroperoxides are formed. A solution of 1 mmole of the phenol in 25 ml. of a N-solution of potassium hydroxide in 90 % ethanol on intensive stirring with oxygen took up 1 mole of the gas within 5 minutes at 40". The mixture was acidified and the hydro- peroxides were extracted with ether and purified by crystallization. The structure of the hydroperoxide (I; X = 0-OH) m.p. 115" obtained in 75 % yield on oxidation of the dibutylphenol has been proved as follows. The presence of one atom of active oxygen was demon- strated by peroxide determination. The product isolated (I; X = OH) m.p. 113" as well as the hydroperoxide have ultraviolet absorption spectra very similar to that of the peroxide (I; X = 0-OBut) which was described by Bickel and K~oyman.~ This peroxide was obtained from both the hydroperoxide (I; X = 0-OH) and the alcohol (I; X = OH) by reaction with tert.-butyl alcohol and tert.-butyl hydroperoxide respectively in 70 % sulphuric acid.Autoxidation of 2 :4 :6-tri-tert.-butylphenol also gave a 75% yield of peroxidic material from which by fractional crystallization two compounds were isolated A hydroperoxide m.p. 104-106" which has structure (11) since its ultraviolet absorption closely resembles that oP(1; X = 0-OH). Structure (111) has been assigned to the other hydroperoxide m.p. 107" (decomp.) its absorption being similar to that of the o-peroxides described by Bickel and K~oyman.~ The mechanism of the reaction is under investiga- tion.The formation of hydroperoxides from phenols has so far been reported only for 10-phenylanthran- 9-01.~ (Received June 17th 1957.) Miiller et a!. Chem. Ber. 1954 87 922 1605; Cook ct al. J. Amer. Chem. SOC. 1953 75 6242; 1955 77 1783; 1956,78 3797; Cook J. Org. Chem. 1953,18 261. Yohe et al. ibid. 1956 21 1289. Bickel and Kooyman J. 1953 3211. 'Julian et at. J. Amer. Chem. SOC.,1935,57,1607; 1945,67,1721; Dufraisse et al. Bull. SOC. chim. France 1948 804. PROCEEDINGS The Crystal Structures and Interatomic Bonding of Chromous and Chromic Fluorides By K. H. JACKand R. MAITLAND (CHEMISTRY KING'SCOLLEGE UPON TYNE) DEPARTMENT NEWCASTLE The unit cell of chromousfluoride a = 4.73; b = 4.72; c = 3-51A; ,8 = 96.5" 1 = 2-43; m = 2.01 ; s = 1.9SA.CRYSTAL-FIELD theory' predicts large distortions from cubic symmetry for octahedral complexes of cations with (i) four unpaired d electrons (e.g. high-spin Cr2+ Mn3+) (ii) six d electrons and one unpaired dyelectron (low-spin Co2+) and (iii) nine d electrons (a2+). The theory has been applied recently to ex- plain the stereochemistry of many cupric com-pounds of palladium complexes,3 and of manganese trifluoride.4~~ Since perfectly regular octahedral co- ordination is impossible if the six ligands are not identical (see Orgel and Dunitz2) structural data for simple binary compounds are of particular interest. The results of a structure determination of chromous fluoride are in complete accord with theory.The unit-cell is monoclinic with the sym- metry of space group P2,/c but in order to show its relation with other MX,-type fluorides the sym- metry P2Jn is chosen (cf. CUF,).~ The cell dimen- sions of specimens prepared by the reaction of hydro- gen fluoride on anhydrous chromous chloride at room temperature (Found F 40.5. Calc. for CrF, F 42-0%) are then a = 4.732 f0.002,b = 4.718 5 0.002 c = 3-505 0*002A,18 = 96.52 & 0.05",V= 77.75 & 0~1081~. For the cell contents Cr,F, = 3-84 g./c.c. &bs. = 3.7 g./c.c. 2 chromium atoms are at O,O,O and *,&,& and 4 fluorine atoms at & (x,y,z) and & (9+ x 8 -y * + z),withx = y = 0-2975 0.003 and z = 0.044 & 0-003.Chromous fluoride is there- fore bostructural with cupric fluoride6 and has a dis- torted rutile-type structure. Octahedra of CrF are joined by sharing corners and the lower symmetry of the structure by comparison with difluorides other than CuF, results from three different bond lengths (2.43 2-01 and 1.98A) within each octa- hedron (see Figure). The empty 3d(x2-ya)orbital of the Cr(rr) atom points in the direction of four fluorine ions and together with the 4s and two 4p orbitals forms four hybrid dsp2 bonds (2.01 and 1-98&. The singly occupied 3d,1 orbital points along the axis of the remaining two Cr-F bonds and must exert a repulsion which accounts for the ab- normally long bond-length of 2-43A. The magnetic moment of CrF (4.3 B.M.*) agrees with the value expected for four unpaired electrons (4.9 B.M.).In contrast chromic fluoride is found to have an undistorted VF,-type transition-metal trifluoride strgcture.' The rhom bohedral unit cell (space group R 3c; a = 5.2643 &-0-0003A,cc = 56.563 0-005") contains 2 chromium atoms at O,O,O and $,+,* and 6 fluorine atoms at & (x,S-x,&) -& (&-x,$,x) and & ($,x,&-x); x = -0.136 -+ 0.003.Each Cr(rri) atom is equidistant from six fluorine atoms which form a regular octahedron around it. As might be expected the Cr-F bond length (1-90& is even shorter than the minimum Cr-F distance in chroni- ous fluoride. In terms of classical valency theory the different Cr-F bonds in chromous and chromic fluorides might be described as having different pro- portions of covalent and ionic character the ionic contribution increasing with increasing bond-length.(Received Jury Ist 1957.) * Determined by Dr. N. Gill Dept. of Chemistry University College London. Orgel J. 1952 4756; Proc. 10th Solvay Conference in Chemistry Brussels 1956. a Orgel and Dunitz Nature 1957 179 462. Harris Nyholm and Stephenson ibid. 1956 177 1127. Hepworth Jack and Nyholm ibid. 1957 179 211. Hepworth and Jack Acta Cryst. 1957 10 345. Billy and Haendler J. Amer. Chem. Soc. 1957 79 1049. Hepworth Jack Peacock and Westland Acta Cryst. 1957 10 63. AUGUST1957 233 The Structure of Cinnabarin By JARLGRIPENBERG (DEPARTMENT FINLAND OF TECHNOLOGY, OF CHEMISTRY INSTITUTE HELSKNGFORS, AND) FOR cinnabarin (polystictin) a derivative of compound gives 2 5-dihydroxybenzoquinone,and phenoxazin-3-0ne,l-~ we advanced the partial struc- it must therefore be 2 5-dihydroxybenzoquinone-3-ture (I),2 which Cavill Clezy and Tetaz3 recently carboxyamide.The formation of this compound extended to (11). New evidence has meanwhile ac- places a hydroxyl group at position 2 but does not cumulated which indicates the complete structure differentiate between positions 1 and 4 for the (III). Only the position of the carbamoyl group is not carboxyamide group. definitely established; it may equally be located at The only remaining question is the nature of the the 4 position. The side chain in structure (I) cannot side chain which can have only one carbon atom and carries the fifth oxygen atom of cinnabarin.Cinnabarin shows only a single reduction wave on polarography due to the quinonoid system, thus excluding other reducible groups e.g. an aldehyde which would moreover fit the analytical results only badly. A primary alcohol is the remaining possibility. That cinnabarin has a second hydroxyl group not directly attached to the chromophoric system is sup- ported by the following facts Cinnabarin acetate be a carboxyl derivative4 and the molecule contains shows an absorption6 at 'L 1725 cm.-l and its a carbamoyl probably attached to the ultraviolet spectrum is virtually identical with that of quinonoid ring. cinnabarin. Cinnabarin methyl ether6 gives a Careful treatment of cinnabarin with alkali gives monoacetate with an absorption band at 1740 cm.-' a compound C,H505N (Found C 45.8; H 2-95; the formulation3 of which as an N-acetyl derivative N 7.4.C,H,O,N requires C,45.9;H 2.75;N,7-65%) is incompatible with the infrared absorption. as a difficultly soluble sodium salt. Hydrolysis of this (Received July 5th 1957.) Cavill and Tetaz. Chem. and Ind.. 1956,986. Gripenberg Honkanen and Patoharju; ibid. 1956 1505. a Cavill Clezy and Tetaz J. 1957 2646. Gripenberg Honkanen and Patoharju Acta Chem. Scand. in the press. Gripenberg and Kivalo Suumen Kern. in the'press. Cavill Ralph Tetaz and Werner J. 1953 525. The Origin of the Terpenoid Structures in Mycelianamide and Mycophenolic Acid. Mevalonic Acid as an Irreversible Precursor in Terpene Biosynthesis R.A. MASSY-WESTROPP S By A. J. BIRCH,R. J. ENGLISH and HERCHEL m (DEPARTMENT UNIVERSITY OF CHEMISTRY OF MANCHESTER) WE report an examination of the incorporation of amide the two substances being formed in approxi- isotopically labelled acetic 3-methylbut-2-enoic and mately constant ratio throughout the growth of the mevalonicl acid into mycelianamide,2 the terpenoid mould. The mould thus provides a means of studying chain of which can be isolated as methylgerani~lene~ the relative effectiveness of various substrates for the and (I) mycophenolic acid4 (11) produced by production of an isoprenoid chain and a structure Penicillium griseofulvum and P. brevi-compactum directly derived from acetic acid.We are able to study respectively. Griseofulvin (III) which previous the same relation in the acid (11) since as will be studies have shown to be derived directly from acetic shown it contains the remnant of a geranyl chain acid is produced simultaneously with mycelian- and an acetate-derived nucleus. The nuclear methyl Wolf Hoffman Aldrich Skeggs Wright and Folkers J. Arner. Chem. Suc. 1956,78 4499. Oxford and Raistrick Biochem. J. 1948 42 323. Birch Massy-Westropp and Rickards J. 1956 3717. Birkinshaw Raistrick and Ross J. 1952 50 630 and earlier papers. Birch Massy-Westropp Rickards and Smith Proc. Chem. SOC.,1957 98. group which is extraneous to this biogenetic scheme has already been shown to be derived from methionine.6 MyceZianamide.-Degradation of the labelled methylgeraniolene obtained by feeding with Me.14C0,H gave results in quantitative agreement with the pattern (I; labelled atoms = *) to be ex- pected for terpene biosynthesis.The efficiencies of incorporation of the tracer into the terpeneu) and the griseofulvin(111) produced simultaneously are of the same order. With Me,C= CH14C02H another pos- si ble isopent ane source me th ylger aniolene (I) with the same pattern of labelled atoms is obtained. The associated griseofulvin has an activity consistent with its formation from the Me.l4CO,H which gaverise to the terpene (I). We conclude that Me,C=CH.14C02H is not incorporated as a unit but undergoes degrada- tion to Me.14C0,H before biosynthesis. Presumably the /l-hydroxy-/l-methylglutaricacid which would be formed by carboxylation of Me,C= CH.14C02H is dissociated by the mediation of coenzyme A into acetate and acetoacetate far more rapidly than it can be converted into the direct isopentane precursor probably mevalonic acid (IV).In contradistinction to these results Bloch Clarke and Harary’ have presented evidence for the incorporation of Me2C=CH-l4CO2Hen bloc into cholesterol by rats and Sanderman and Stockmad have made similar observations on the incorporation of the same com- pound into pulegone by Mentha pulegium L. Feeding of [~~-~~C]mevalonic acidg gave labelled methylgeraniolene the degradations of which agree with the distribution (I;labelled atoms = f) to be predicted on the basis of incorporation of the mevalonic acid as a unit.No appreciable amount of 14CH,C0,H can have been produced since the associated methylgeraniolene is completely inactive. PROCEEDINGS The status of mevalonic acid (IV)as an irreversible intermediate in terpene biosynthesis is thus revealed. Mycophenokc Ac~~.-M~.~~CO,H produces the expected labelling pattern (II) with an equal incor-poration of the tracer into the nucleus and the side chain. Using Me&= CHS~~CO,H the results obtained with methylgeraniolene are confirmed in that the pattern (11) is again obtained; the extent of labelling is however slightly higher in the side chain than in the nucleus. The terpenoid origin of the C chain is demonstrated by the incorporation of [a-14C]meval-onic acid into mycophenolic acid (11).The nucleus is compIetely unlabelled and all the activity is present in the laevulic acid obtained by ozonolysis. Further proof that mevalonic acid is a specific intermediate in terpene biosynthesis is thus provided. The incorporation of mevalonic acid (IV) into polyisoprenoid substances involves decarboxyla-tion.1° We believe that this process probably involves initial oxidation to the formyl-acid (V) decarb-Ye Me&=CH CHO &H,C=CH CHO I + ca ?H fyle Me,C=CH CH CH C=CH CHO lH Me,C=CH CH CH C=CH CH Ye j-Hzo Me2C=CH CH-CH C=CH CH oxylation of which as its anion will be favoured by its structure as a “vinylogue” of a /l-formyl-acid. Reaction of the resulting anion with the carbonyl group of another similar unit (or with /3-methyl- crotonaldehyde produced by proton addition) could then occur.The process might continue indefinitely since the necessary activation is provided by the group added at the end of the chain. Dehydration or hydrogenolysis of the intermediate alcohol would give respectively conjugated polyenes of the caroten- oid type or polyisoprenoid structures. We thank the University of Manchester for a Science Research Scholarship (to R.A.M.-W.) the Cumberland Education Committee for a grant (to R.J.E.) Mr. J. Schofield and Dr. R. H. Cornforth (Mill Hill) for the synthesis of 3-methyl[1-14C]b~t-2- enoic and [a-14C]mevalonic acid respectively and Miss M. Hay for mycological work. (Received June 24th 1957.) * Birch English Massy-Westropp and Smith Proc.Chern. SOC., 1957 204. Bloch Clarke and Harary J. Amer. Chem. Sue. 1954 76 3859. Sanderman and Stockmann Natwrwiss. 1956 43 580. @ Cornforth and Cornforth unpublished work. loTavormina Gibbs and Huff J. Amer. Chem. SOC., 1956 78 4498. AUGUST 1957 235 FORTHCOMING SCIENTIFIC MEETINGS Aberdeen Friday October 4th 1957 at 7.45 p.m. Lecture “Fatty Acids of Blood,” by Dr. G. A. Garton B.Sc. Ph.D. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry. To be held at Marischal College. Bristol Monday September 9th 1957 at 5.30 p.m. Lecture “Non-aqueous Ionizing Solvents with special reference to Thionyl Chloride and Tin Tetra- chloride,” by Professor Hans Spandau.Joint Meet- ing with the Student Chemical Society. To be held in the Chemistry Department The University. Manches t er Wednesday October 2nd 1957 at 2.30 p.m. Symposium “Newer Metals.” Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry. To be held in the Large Lecture Theatre Chemistry Department The University. NEWS AND ANNOUNCEMENTS Birthday Honours List.-Awards to Fellows an- nounced in the Birthday Honours List include Professor E. L. Hint President of the Society (C.B.E.) . Honorary Fellows of the Royal Society of Edin-burgh.-Sir AZexander Fleck Chairman Imperial Chemical Industries Limited and Sir Rudolph Peters Professor Emeritus of Biochemistry in the University of Oxford have been elected Honorary Fellows of the Royal Society of Edinburgh.The Royal Society and Naed Foundation Com-monwealth Bursaries §theme.-The Royal Society have announced an award to Professor Karimullah Professor of Organic Chemistry and Director of the Institute of Chemistry Panjab University Lahore to enable him to study research techniques etc. in natural-products chemistry at Cambridge for about three months from July 1957 and one to Dr. J. A. Pople University Lecturer in Mathematics Cam- bridge to enable him to carry out research on the theory of nuclear magnetic resonance at the National Research Council Laboratories Ottawa in August and September 1957. University of §heffield.-It is announced that Imperial Chemical Industries Limited have given E25,OOO towards the cost of extensions to the depart- ments of chemistry fuel technology and chemical engineering of Sheffield University.The chemistry block was opened in 1954 but it is already too small for the increasing number of students. Plans have been prepared for the addition of an East wing with large teaching laboratories and a West wing for Staff and research. The &st stage of the extensions is due to begin this year. Personal.-The title of Professor Emeritus of Physical Chemistry in the University of London has been conferred on Professor William Wardlaw C.B.E.,on his retirement from the Chair of Physical Chemistry at Birkbeck College. Dr. R. N. Haszeldine has been appointed to the Chair of Chemistry at the Manchester College of Science and Technology.Dr. J. H. Skellon has been appointed Head of the Department of Chemistry at the Brunel College of Technology Acton London which is to be opened in September. The University of Birmingham have announced the appointment of Dr. W. I. Stephen as a Lecturer in Chemistry from October lst and that the title of Reader in Organic Chemistry has been conferred on Dr. J. C.Tatlow. St. John’s College Oxford have announced the election of Mr. R. 0.C. Norman Merton and Balliol to a Lectureship in Organic Chemistry. Dr. N. StoZow recently of London has taken up the post of Head of the Department of Conservation and Scientific Research at the National Gallery of Canada Ottawa.Dr. L. VaZentine formerly Lecturer in the Chem- istry of High Polymers in the Department of Textile Industries the University of Leeds has taken up an appointment in the Research Department Tootal Broadhurst Lee Co. Ltd. Oxford Street Man- Chester 1. Deaths.-The death occurred on July 3rd of Dr. Gerald Roche Lynch a Fellow of the Chemical Society since 1908. Dr. Roche Lynch was formerly Director of the Department of Chemical Pathology St. Mary’s Hospital London and Senior Otficial Analyst to the Home Office. We also regret to announce the death of Mu. Frederick Walter Goddard on July 21st. Elections to the Fellowship.-52 Candidates for Fellowship whose names were given in the Proceed- ings for June were elected on July 8th.PROCEEDINOS OBITUARY NOTICES THOMAS EWAN 1868-1955 MANCHESTER SCHOOL GRAMMAR has been the cradle of many noted scientists and among them must be recorded the name of Thomas Ewan. He was a true Mancunian being born in that City on July 23rd 1868. He went straight from the Grammar School to Owens College took his B.Sc. with 1st Class Honours in 1889 and was awarded the Mercer Scholarship. Even at this stage we see the promise of a brilliant career for his earliest publication-“Oxidation Pro-ducts of Acenaphthene”-appears in the Journal for 1889 coupled with the name of J. B. Cohen. His first post-graduate research was however carried out on the Continent at Munich where he was awarded his Ph.D. in 1890. Very soon he returned to Owens College and with an 1851 Exhibition continued his research career.In 1893 he again went to the Con- tinent and spent a year at Amsterdam working with van’t Hoff. On his return in 1894 he took a post as demonstrator in chemistry at the Yorkshire College -now the University of Leeds-which he held until 1896 when he was awarded his Master’s degree at Owens College. Although he was essentially a physical chemist his researches covered a wide field. He was mainly interested in the properties of aqueous solutions and published papers on absorption spectra osmotic pressure and vapour pressure of various solutions. In addition however we find papers on such subjects as “Action of Ethylic Oxalate on Dibenzyl Ketone” and “Rate of Oxidation of Phosphbrus Sulphur and Aldehyde,” “Electrolytic Conductivity of Formanil- ide and Thioformanilide.” In 1896 he left academic work and joined the staff of the Aluminium Company at Oldbury a Company founded by H.Y.Castner. When Dr. Ewan went to Oldbury sodium was being made there by the elec- trolysis of fused caustic soda in the cells devised by Castner and the development of Castner’s process for making sodium cyanide from sodium ammonia and charcoal was well under way. Castner’s original interest in sodium was as a reducing agent in the production of aluminium but the development of the electrolytic process for making aluminium led him to seek alternative uses for sodium. One of these was his process for making sodium cyanide.It fell to Dr. Ewan to complete the experimental work on the cyanide process and some three years later to super- vise the construction and starting up of a plant to make sodium by Castner’s process at Rheinfelden and the first Castner cyanide plant at Frankfurt. In 1895 the Castner-Kellner Alkali Company was formed to operate Castner’s mercury-cell process and in 1901 the Aluminium Company’s Works at Old- bury were closed down. Dr. Ewan joined the staff of the Cassel Gold Extracting Company later the Cassel Cyanide Company who had arranged to make cyanide by Castner’s process in Glasgow. After Im- perial Chemical Industries Limited had been formed the manufacture of cyanide was transferred from Glasgow to Billingham-on-Tees and Dr.Ewan joined the research staff there in 1930. During the thirty years that he inspired and controlled the research work of the Cassel Company an astonishing variety of investigations was prose- cuted some of them on a large scale. Dr. Ewan has recorded that in the early days at Oldbury Castner kept so closely in touch with the progress of the research that he required a report every day. Castner’s example clearly made a deep impression for Dr. Ewan also insisted on knowing all the details of the work that was going on-and in the pursuit of facts he paid no regard whatever to the passage of time. The result was that he gained a knowledge of chemistry that certainly merited the Baconian epithets for it was full and exact and ready.When he came to Billingham he brought with him a wealth of experience in the chemical industry that was of incal-culable value in a young organisation. It was there- fore doubly a matter for regret to his colleagues that for private reasons he decided to retire early in 1933. Thomas Ewan spent his life in the service of Chemistry; he contributed by his personality and his writings not only to the academic and industrial fields but more important also to the inspiration of the younger chemists who followed him. He died at his home in Strathblane near Glasgow on September 4th 1955 at the age of 87 and those who had worked with him found themselves speaking of him in the terms of reminiscent admiration that he had used in speaking of Castner.The cyanide process he helped to develop in the late nineties is still holding its own in the atomic age. I. J. FAULKNER. AUGUST 1957 237 ALLAN FREDERICK WALDEN 1871-1 956 ALLANFREDERICK for thirty years Fellow WALDEN and Tutor of New College Oxford was born at Ware on September 16th 1871. He died in his 85th year on April 19th 1956. His father Keith Walden was a Congregational Minister who held pastorates at Ware Oxford Halifax and Brighton. His mother (nke Blanchard) died when he was four years old. Walden was educated on the classical side at Bradford Grammar School until he reached the VIth Form then he changed to the modern side. He went up to Magdalen College in 1891 as an Open Science Exhibi- tioner and was placed in the First Class of the Final Honour School of Chemistry in 1895.After taking his B.A. Walden remained at Oxford as a free-lance tutor and was so successful that in 1897 he was appointed Lecturer in Chemistry at New College. At the same time he joined the Rev. G.B. Cronshaw in the teaching of Chemistry at the Queen’s College laboratory where later F. D. Chattaway did much of his best work. About 1904 Walden became one of the earliest paid demonstrators in Odling’s labora- tory. His co-demonstrators in those early years were Dr. Bertram Lambert N. V. Sidgwick and F. D. Chattaway. He remained a demonstrator in the same building which is now incorporated into the new Inorganic Chemistry Laboratory until his retirement in 1939.In 1908he was elected Fellow of New College and remained a Fellow for thirty years. He was elected into Fellowship of the Chemical Society on May 4th 1899. Walden was an exceptionally able tutor and lec- turer. He devoted his life to teaching and since every- thing he undertook had to be done perfectly no pains being spared he made of it an art. The crystal clarity and seemingly effortless spontaneity of his dis- courses on chemistry whether in tutorials or in the lecture theatre had the perfection of an acquired artistry. New College undergraduates always ad- dressed him as “Teacher” a name which was at once a tribute to his unique ability and a term of affection. Unlike the College tutor of today he did not confine himself to one branch of chemistry but ranged over the whole subject always impressing upon his pupils that chemistry was one subject not three.He was proud of the fact that the Chemical Society embraced all branches of the subject in its Journal and was im- patient of the rivalry between the physical and organic chemists of his day especially at Oxford. He had a warm and generous nature; the shy student was swept rapidly into friendly intimacy with him. His enthusiasm for his subject was infectious; he made chemistry exciting. Knowing Walden was itself an exciting experience; he seemed to see life in more vivid colours than ordinary mortals and he always dramatised and embellished his accounts of people and events. He was renowned among his pupils and colleagues for his inimitable stories which usu-ally composed on the spur of the moment recounted the most unlikely adventures on his part yet were told in all seriousness and with such a wealth of cir- cumstantial detail that for the moment listeners were beguiled into believing them to be true.He married in 1921 Miss Renke Berlein but the marriage was later dissolved. He had one daughter Elizabeth Anne (Betty) who died in 1942 at the age of twenty when on active service with the Wrens. H. R. ING. HERBERT LEVINSTEIN 1878-1 95 6 LEVINSTEIN HERBERT was born on February 2nd 1878 at Prestwich near Manchester. He was one of the three sons of Ivan Levinstein who left his natal Charlottenburg in 1864 to settle in Blackley indif- ferent to his grandfather’s warning that the artificial- dyestuffs industry had already passed its zenith.Fourteen years later when Herbert Levinstein was born there would have been more substance in such forebodings at least so far as this country was con- cerned. Most of the early English pioneers had re- tired from active business. Cassella and Bayer Elberfeld were about to reinforce the rising tide of German competition and the British dyemaking in- dustry was beginning a decline to that parlous state which could so easily have spelled defeat in the First World War. Herbert Levinstein was destined to be one of those who undismayed by the relentless German economic warfare up to 1914 contributed notably to the victory at arms and to the renaissance of the British organic chemical industry.After completing his education at Rugby he studied chemistry at the University of Manchester under W. H. Perkin junior and obtained his M.Sc. degree in 1898. It was from Zurich where he was engaged in research for his Ph.D. that he published his first paper in collaboration with Bamberger and Schmidt on the action of diazobenzene on nitromethane (Ber. 1900,33,2043). In 1900 Dr. Levinstein joined his father’s firm at Blackley Manchester to undertake research on sulphur colours under Dr. Mensching which was rewarded by the grant of his first two patents (B.P. 7,871;12,229/1902). At this time the greater part of the Blackley works was devoted to the manufacture of intermediates most of which was shipped to Germany for conver- sion into dyes.By 1907,when Levinstein succeeded Dr. Hirschberger as works manager this trade had declined to an alarming degree. The factory could neither absorb its own intermediates nor sell them abroad. The only alternative to virtual extinction was a change in the whole basis of the business by a substantial increase in the sale of dyes and a widening of the range. In 1909 the future Perkin Medallist James Baddiley,left Leeds University ready to dedicate his life and his talents for research and organisation to the British dyestuffs industry. He was engaged by Dr. Levinstein as his personal assistant. The partner- ship marked the inception of a vigorous research policy which not only provided the firm with over 150chemically distinct dyes by 19 14 but also created the main bulwark against fierce German competition up to the outbreak of war.About the time Baddiley came to Blackley no small part of German research activity was directed towards investigation of derivatives of J acid (2-amino-5-naphthol-7-sulphonic acid) as compon- ents of azo-dyes characterised by cotton substan- tivity. Identification of Bayer’s Benzo Fast Red 8BL and recognition of benzoyl-J acid as a constituent induced Levinstein and Baddiley to embark on a comprehensive programme of research in this field with such results that they successfully obtained several patents (B.P. 1 1,877; 15,068; 15,070; 26,577/1910; 12,281/1911). The development of a range of cotton colours based on derivatives of J acid was no small achievement.In 1910Dr. Levinstein was involved in the famous Vidal Black case in which the Vidal syndicate at- tempted to establish their B.P. 16,449/1896as a master patent. At first Levinstein Ltd. were held to have infringed the process claimed by Vidal but the judgment was reversed by the Court of Appeal before Lord Moulton and Lord Justice Buckley. Most of Dr. Levinstein’s 25 patent specifications relate to azo-dyes and intermediates. He was respons- ible for much of the work on trisazo- and tetrakisazo- dyes with resorcinol or m-aminophenol as end components. They constituted the Vulcan range of Levinstein Ltd. and were intended for after-treatment on the fibre with formaldehyde to enhance washing- fastness by formation of more complex and less PROCEEDINGS soluble products (B.P.27,525; 28,296/1912; 1,435-6 25,547; 28,569/19 13;8,569/ 19 14). On the death of his father in 1916 Dr. Levinstein assumed full control of the works. It was due to his own initiative in approaching the Government within a few days of the outbreak of hostilities that the British and allied armed forces never lacked dye for their uniforms. From 1917 onwards with generosity and public spirit so familiar to those who knew him Dr. Levinstein provided the War Office without charge with all the acriflavine and proflavine so necessary to the treatment of war wounds. As a member of the Chemical Warfare Committee he made yet another contribution to the common cause.He was responsible early in 1918 for the development of a simple and rapid process for the manufacture of mustard gas. Without other reward than the gratitude of the American Government he presented them with plans of both plant and process. Despite the exigencies of war the research effort at Blackley gradually increased. After the cessation of hostilities Dr. Levinstein strove hard to maintain the independence of the firm in the future of which he so ardently believed and which had been created and controlled by his family and those who had grown up in it. Yet he could not indefinitely withstand strong Government pressure and as he himself ex- pressed it as a matter of patriotism and not of business he eventually consented to the arnalgama- tion of Levinstein Ltd.and the Government-sponsored British Dyes Ltd. brought about by Lord Ashfield President of the Board of Trade. Dr. Levinstein became joint managing director with Sir Joseph Turner until termination of the agreement in February 1921,but he remained a member of the board until his resignation in 1922 at the age of 44. Although his official responsibilities in the dye- making industry then came to an end Dr. Levinstein found no lack of opportunity in other fields. Early in the century his father had acquired an interest in the Murgatroyd Salt & Chemical Co. Ltd. and for many years Herbert Levinstein was a technical director. He eventually became Life President in recognition of his contribution to the development of the modern Elworth works.He was an original director of Nuera Art Silk Co. Ltd. and from 1928 a technical director of Lansil Ltd. From 1941 until 1946 he was also technical director of Williams (Hounslow) Ltd. Dr. Levinstein was the recipient of many honours so gladly given to one who had so truly earned them. He was a Freeman of the City of London (1923)and Prime Warden of the Worshipful Company of Dyers (1947). He was President of the Manchester Literary and Philosophical Society (1925-7) and of the British Association of Chemists (1923-4 and 1949-50) which conferred on him the Hinchley AUGUST1957 Medal. He was President of the Society of Dyers and Colourists (1927-8) as well as President and Gold Medallist of the Society of Chemical Industry (1929-30) and of the Institution of Chemical Engineers (1935-7).Dr. Levinstein was an accomplished lecturer with a deep interest in the history of chemical industry and a wealth of personal reminiscence. In 1938 he delivered the Perkin Memorial Lecture at a joint meeting of the Chemical Society of which he became a Fellow in 1914 and the Society of Chemical In- dustry. He gave the Fifth Gluckstein Memorial Lec-ture to the Institute of Chemistry in 1933 and the First George Douglas Lecture before the Society of Dyers and Colourists in 1949. Dr. Levinstein was married on December 22nd 1914 to Isabella Forrest Crawford daughter of Professor William Stirling who held the Chair of Physiology in the Universities of Aberdeen and Manchester successively.Mrs. Levinstein survives her husband. An enthusiastic and versatile sportsman a keen rugger player and a mountaineer in his younger days Dr. Levinstein found pleasure and relaxation in the hunting field and in yachting. The memory of his outdoor pursuits doubtless helped to sustain him during the physical misfortunes of his closing years. Those who saw him at the Perkin Centenary Celebra- tions last year could not fail to understand his ability to command not only the loyalty but also the esteem and affection of his staff. His qualities of courtesy patience and vivacious charm were no less evident because of the physical handicap with which he so gallantly contended.Not many weeks later he was struck by sudden illness at his home at Pinkneys Green near Maidenhead and died on August 3rd 1956 in Windsor Hospital. His firsthand and abiding interest in research and his ardent belief in the future of British chemical industry inspired many who have earned for themselves as he did honoured names in those fields of endeavour to which he so generously dedicated his life. W. H. CLIPFE. APPLICATIONS FOR FELLOWSHIP (Fellows wishing to lodge objections to the election of these candidates should communicate with the Honorary Secretaries within ten days of the publication of this issue of Proceedings. Such objections will be treated as confidential. The forms of application are available in the Rooms of the Society for inspection by Fellows.) Archer Arthur Allan Peter Giles MSc.King’s College Cambridge. Ash Anthony Stanley Fenton B.Sc. Ph.D. A.R.I.C. “Wirreanda,” Wood Meads Epping Essex. Badrick Michael John. Flat 3,92 Leather Lane Holborn London E.C.l. Balasubramanian Muthukumarasamy B.Sc. M.A., Ph.D. Annamalai University Annamalainagar India. Basu Sadhan D.Sc. Department of Chemistry College of Science 92 Upper Circular Road Calcutta 9 India. Bernasconi Raymond D.Sc. c/o Jackson 6 Mingarry Street Glasgow. Blair James McDonald B.Sc. 324 Malden Road New Malden Surrey. Bradshaw James Ronald A.R.I.C. 44 Bramble Rise West Dene Brighton 5 Sussex. Broadbent Hyrum Smith B.S. Ph.D. Department of Chemistry Brigham Young University Provo Utah U.S.A.Bromham Norman Hugh B.Sc. “Marlborough,” 29 Ormes Road Skewen Neath Glamorgan. Bunn Dennis B.Sc. Ph.D. A.R.I.C. Department of Physical Chemistry The University Leeds 2. Caspi Eliahu Ph.D. Worcester Foundation for Experi- mental Biology 222 Maple Avenue Shrewsbury, Massachusetts U.S.A. Chatamra Boonbhrugsa B.Sc. 4 Beechbank Road, Liverpool 18. Crayford John M.Sc. 11 Park Road Ramsgate Kent Eisenberg Henryk M.Sc. Ph.D. The Weizmann Insti- tute of Science Rehovot Israel. Eve Adrian John M.Sc. Chemistry Department Univer- sity College of Rhodesia and Nyasaland P.Bag 167 H, Salisbury Southern Rhodesia. Fell Gordon Stephen B.Sc. Department of Chemistry The University Glasgow. Gibbons Richard Alexander B.Sc. Ph.D. A.R.I.C. The National Institute for Research in Dairying Shinfield Reading Berks.Gilbert John Norman Tracey B.Pharm. 11 Argyll Road Westcliff-on-Sea Essex. Hamilton Richard John 57 Glasgow Street Ardrossan Ayrshire Scotland. Hatch Lewis Frederic B.S. M.S.,Ph.D. Department of Chemistry The University of Texas Austin 12 Texas, U.S.A. Isaacs Royston Keith M.P.S. Ph.C. D.B.A. 5-14 North-wood Hall Highgate London N.6. King Geoffrey Stephen Douglas M.Sc. A.R.I.C. European Research Associates S.A. 95 Rue Gatti de Gamond Brussels Belgium. Kitahonoki Keizo D.Pharm. Ikoma-cho Ikoma-Gun Nara-Pref. Japan. Kotera Katsumi D.Sc. Kotsubo Senriyama Suita-shi Osaka Japan. Kubba Ved Parkash M.Sc. Chemistry Department Queen Mary College Mile End Road London E.l.Lower Stephen Kent B.A. Department of Chemistry Oregon State College Corvallis Oregon U.S.A. Marriott John Ernest B.Sc. 19 East Way Drayton Berks. Mehrishi Jitendra Nath M.Sc. Department of Physical Chemistry Free School Lane Cambridge. Minato Hitoshi D.Pharm. 3-9 Matsugaedori-Zchome Toyonaka-shi Osaka Japan. Nagata Wataru D.Pharm. 88 Kawahigashi-cho, Nishinomiya-shi Japan. Osborn Alan John B.Sc. 126 High Street Luton Beds. Pradhan Suresh Krishnarao MSc. A.R.I.C. Depart- ment of Organic Chemistry The University Glasgow. Read Elsie B.Sc. 5 Wellfield Terrace Todmorden Lancs. Revill John Pattison B.Sc. 101 Washington Grove Doncaster Yorks. Rosseinsky David Reuben B.Sc. Department of Chem- istry The University Manchester.ADDITIONS TO History of chemistry in ancient and medieval India incorporating the history of Hindu chemistry. A. P. C. RGy. Edited by P. Riiy. Pp. 494. Indian Chemical Society. Calcutta. 1956. The molecular theory of solutions. I. Prigogine A. Bellemans and V. Mathot. Pp. 448. North-Holland Publ. Co. Amsterdam. 1957. Korrosion und Korrosionsschutz. Edited by F. Todt. 20 contributors. Pp. 1102. Walter de Gruyter and Co. Berlin. 1955. Chemisorption :a symposium held at Keele Stafford- shire by the Chemical Society 1956. Edited by W. E. Garner. Pp. 277. Buttenvorths Scientific Publ. London. 1957. (Presented by the publishers.) Technique of organic chemistry. Edited by A. Weiss- berger. Volume X. Fundamentals of chromatography. H. G.Cassidy. Pp. 447. Interscience Publ. Inc. New York. 1957. Chemie und Technologie der Paraffin-kohlenwasser- stoffe. F. Asinger. Pp. 7 19. Akademie-Verlag. Berlin. 1956. Chemie der Zucker und Polysaccharide. F. Micheel and A. Klemer. 2nd Edn. Pp. 512. Akademische Verlags- gesellschaft Geest und Portig K.-G. Leipzig. 1956. Estudio de la difenilditiourea y de su comportamiento como reactivo de varios metales nobles especialmente del paladio. J. Fuentes Duchemin. (Universidad de La Laguna. Facultad de Ciencias. CAtedra de Quimica Analitica. Tesis Doctorales VI). Pp. 85. Universidad de La Laguna. Canary Is. 1957. (Presented by the author.) The terpenes. Vol. 4. The triterpenes and their deriva- tives hydrocarbons alcohols hydroxy-aldehydes ketones and hydroxy-ketones.(The late) Sir John Simonsen and W. C. J. Ross. Pp. 524. Cambridge University Press. Cambridge. 1957. Vitamin A. T. Moore. Pp. 645. Elsevier Publ. Co. Amsterdam. 1957. Chemistry of heterocyclic compounds. Edited by A. Weissberger. Vol. X. The 1,2,3- and 1,2,4-triazines, tetrazines and pentazines. J. G. Erickson P. F. Wiley and V. P. Wystrach. Pp. 261. Interscience Publ. Inc. New York. 1956. Modern cereal chemistry. D. W. Kent-Jones and A. J. Amos 5th Edn. Pp. 817.,The Northern Publ. Co. Ltd. Liverpool. 1957. (Presented by the authors.) Neueste Fortschritte und Verfahren in der chemischen Technologie der Textilfasern. Part 2. Neue Verfahren in Smith Arnold John B.Sc. Ph.D. A.R.C.S. D.I.C. “Bramley,” 1 39 Hivings Hill Chesham Bucks.Smith Peter John Allan B.Sc. A.R.I.C. 5 Hursley Road Chandler’s Ford Near Eastleigh Hants. 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ISSN:0369-8718
DOI:10.1039/PS9570000217
出版商:RSC
年代:1957
数据来源: RSC
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