PROCEEDINGS OF THE CHEMICAL SOCIETY AUGUST 1962 FARADAY LECTURE* The Mechanism of Olefin Elimination By Sir CHRISTOPHER INGOLD THEreactions which for brevity I shall call simply “eliminations,” would be more particularly described as olefin-forming heterolytic 1,Zeliminations. They are formulated in general terms in Fig. 1. They include notably olefin formation by base attack on alkyl ’onium ions and alkyl halides. In the formula- tion B is any base which can pull out the proton and X any group which can carry away its bond-electrons. Mechanism E 2 + H-Cfi-Cd-X --c x r7n BH + CP=cA+ Mkhanism EI 8;OH ORS R3N ROH ,H,O ,etc. X;NR:,SR ,NO2 S02R O.SO,R,Hal,etc. FIG.1. He tero lytic olefin-forming 1,2-eliminations Both B and X may initially be in either of two states of electrical charge; but after reaction B will be formally one unit of charge more positive and X one unit more negative than before.It was not until the later 1920’sthat olefin-formkg reactions of ’onium ions and of alkyl halides as well as of some other classes of compounds such as sul-phones and sulphonates began to be seen as varieties of the same general reaction. However from the time that that was understood the theory of the mechanism of elimination has developed side by side with that of nucleophilic substitution and on similar lines; for as Hughes first appreciated,l an elimina- tion is an internal nucleophilic substitution at the a-carbon atom with the /%carbon atom as the attacking nucleophile.In so far as the bond exchange at the a-carbon is concerned he argued elimination had to have available to it the kinetically distinguish- able bimolecular and unimolecular mechanisms of nucleophilic substitution. In 1935 he demonstrated a corresponding duality of mechanisms of elimina- tion as formulated on Fig. 1. In bimolecular elimination E2 the concerted bond-changes proceed in a single step. In unimolecular elimination El the electron-holding group X is first heterolysed in a rate-controlling step and then proton-transfer from the resulting carbonium ion rapidly ensues. These two mechanisms are even today the only kinetically well-authenticated mechanisms of elimination. As I shall mention later a third mechanism is con-ceptually possible and may have a limited practical range; but good conditions for its demonstration have not yet been found.The story of the analysis of constitutional effects on the direction and rate of eliminations starts around a century ago with observations made and SUM-* Delivered before the Society at the Royal Institution London on March 22nd 1962. Hughes J. Amer. Chem. SOC.,1935 57 708. 265 marising rules offered for eliminations from parti- cular classes of substrate. This was long before it was appreciated that such eliminations are members of a common family of reactions. In 1851 Hofmann noticed2 that quaternary ammonium hydroxides containing different primary alkyl groups gave mainly ethylene if an ethyl group was present.It has relatively recently been shown that this rule is valid in the more general form that quaternary ammonium hydroxides containing only primary alkyl groups (an important qualification) give mainly that ethylene which carries the smallest number of alkyl substituents? We can call that the “generalised Hofmann rule.” Hofmann himself did not go so far obviously he could not have done so at that early date. In 1875 Saytzeff4 noticed that secondary and tertiary alkyl halides that were sufficiently unsym- metrical to give different olefins by elimination in the unequal branches of the alkyl chain preferentially lost hydrogen where there was least hydrogen. That is how he put it but it amounts to the same to say that they give mainly that ethylene which carries the largest number of alkyl substituents.As long as no connexion was recognised between the reactions to which they applied no-one thought of comparing these rules. That remained the situa- tion for half a century. However as soon as elimina- tion was recognised as one comprehensive family of reactions then the antithetical nature of the rules stood out and it became a challenge to discover from what kind of constitutional influence each one arose. From the outset the philosophy was that the respec- tive influences would be general that is operative throughout the length and breadth of organic chem- istry and not only in the limited field of simple alkyl structures to which the antithetical rules even in generalised form alone applied.Both influences would be present always. They would be inde- pendently energised so that they could work either in conjunction or in opposition in the latter case leading within certain fields to antithetical rules according to which was dominant. The important problem was to identify these general constitutional influences. If this could be done the special con- sequence that called attention to them ought to receive its explanation automatically. Half this question was answered in 1927 when it was proposed3 that the general influence from which sprang the Hofmann rule for alkyl groups in ’onium decompositions was one of the poZarity of sub- stituents acting on the acidity of the p-proton. * Hofmann.Annalen. 1951.78 253 79. 11. Hanhart and Ingold J. 1927,997. PROCEEDINGS TABLE 1. E2 rates (k in 1.mole-l sec.-l) in ethanol af 30” of OEt-P-R*C~H~.CH,.CH,XIP-R.C,H,.CH :CH x= ;7 SMezf Br R (1@kd ( 05k2) Me0 11 16 Me 23 23 H 50 42 Cl 244 191 CO-Me -720 NO2 -75,200 Outside the area of simple alkyl groups it was shown then and still better subsequently that sub-stituents of definite polarity influenced elimination in the expected way. A good recent demonstration of this nature is one by Saunders and Williams,6 who measured the rate of bimolecular elimination E2; under the agency of ethoxide ions in ethanol of some para-substituted phenethylsulphonium ions and bromides. Some of their rate constants are in Table 1.It is qualitatively obvious from the series starting with methoxyl and ending with nitroxyl of groups in order of their influence on rate that a polar effect is under observation. As one sees from the spread of the figures the effect is stronger for the sulphonium ions than for the bromides but is quali- tatively the same for both series of substrates. Saunders and Williams made their test for a polar origin of the effect quantitative by comparing the logarithms of the rates with Hammett’s (T values or u* values which are recognised measures of the polarity of the substituents. The diagnostic linear relation for the bromides is shown in Fig. 2.It may be recalled that a measures polarity when it can be treated as a constant property of the substituent whereas a* takes account of the enhanced polarity that arises from the improved conjugation that some substituents will gain in the course of the reaction which they are influencing.Thus the para-acetyl and para-nitro-groups would require their distinctive us values to express their effect on the ionisation of phenols because their conjugation increases as the acidic proton is lost. The fact that cr* values rather than u values are needed in these eliminations in order to maintain the linear correlation shows not only that we are indeed dealing with a polar effect but also that it is one on the loss of a proton con- jugatively related to the para-substituents as is the /%proton in these systems. Saytzeff Annalen 1875 179,296.Saunders and Williams J. Amer. Chem. SOC.,1957 79 3712. AUGUST 1962 5.0-4.0-r' Q, - 3.0-v) -0.2 02 0.6 I *o u- FIG.2. E2 of p-RC,H,-CH,CH,Br. 0 = U-value; 0 = a*-value. (Reproduced by permission from Saunders and Williams J. Amer. Chem. Soc. 1957 79 3714.) With simple alkyl groups there is no inherent polarity in the group but only such polarity as is induced by the only polar substituent present the electronegative departing group. This induced polarity is strongest when the departing group is an 'onium ionic pole; and it then becomes the strongest orienting influence present provided that the mech- anism of elimination is bimolecular E2 so that strong unsaturation does not develop too early in the reaction (we shall see later why that is important) and provided also that the simple alkyl structure is kept below certain thresholds of complexity (above which steric hindrance might enter).In these condi- tions we get elimination oriented according to the generalised Hofmann rule and showing as pointed out below the rate comparisons demanded by the polar interpretation of that rule. The Hofmann rule itself refers to orientation. A large number of investigations of product composi- tions in 'onium eliminations have been published since these explanations were given. One of the best is that of Smith and Frank,6 who mass-spectro- metrically analysed the oleh mixtures formed from quarternary ammonium hydroxides containing different olefh-forming alkyl groups.Some of their results are shown in Table 2. The second set of figures in which the same two groups are present in different ratios give olefin compositions which are different but become identical after statistical cor- rection for the varying initial abundances of the groups this shows that the different alkyl groups in the ammonium ions act independently of one another. This being understood the results in general show an orienting effect attenuated by relay in the way that is characteristic of polar effects. ?-Carbon that is the fist carbon beyond the acidic /%proton orients strongly &carbon mildly and a second &carbon equally mildly. Unlike polar effects steric effects do not attenuate; on the contrary once they start they mount rapidly with increasing material density around the reaction centre.The third &carbon in the most branched group neohexyl does orient more strongly than either the first or the second and it is very probable that as Smith and Frank suggested a steric effect impinges at this point. TABLE 2. Olefinsfrom quaternary ammonium hydroxides. Alkyls in R,N+ MY1 extension beyond Cg % Olefins found Lower Higher For equal nos. groups A Lower Higher Et, Prn C- 96 4 96 4 PP, Bun Pm Buns PP, Bun C-C-C-9 ?9 9 7 62 38 36 64 83 17 62 38 62 38 61 39 Bun2 (isopentyl) Bun isopentyl Me c\C-C-C-C/ , 9? 3367 66 34 67 33 66 34 c\ c\. isopentyl neohex Me C-G-C-91 9 91 9 c/c/ (I Smith and Frank J. Amer. Chem. SOC.,1952 74 509.With the tool of kinetics one can probe further than by product analysis alone. The induced polarity in an alkyl extension beyond the /3-carbon atom is electropositive with respect to the ,&carbon so tend-ing to retain the @proton. It therefore follows from our interpretation of the Hofmann rule that in fields of elimination where that rule prevails alkyl exten- sion beyond the /%carbon should lead to diminished rates the diminutions showing polar attenuation. That should be true whether the structure admits an orienting effect or not and cases of both kinds are illustrated by observed rates’ in Table 3. One sees TABLE 3. (A) RNMe3+ iOEt-3 Olefin + HOEt + NMe (B) RSMe,+ + OEt-+ Olefin + HOEt + SMe E2 rates (k in I.mole-l sec.-l) in ethanol.R . . Et Prn Bun Bui (B) 105k (64”) (A) 10G,’(1000j’ 60 8.9 27 0.72 17 0.47 14 - R .. .. .. .. .. Pri Bus longer branch 52 18 (B) 104k (w){ shorter branch 52 51 R .. .. .. .. .. But CMe,Et longer branch 27 8 (B) 105k2(25’){ each shorter do. 27 24 (Hughes et al. 1941;Dhar et al. 1948) the rates falling and the fall tailing off. When the group is unsymmetrical enough to admit an orienting effect as in the s-butyl and t-pentyl examples the effect arises because rate in a lengthened chain has been reduced and not because a competing rate has been increased. Recently Banthorpe Hughes and Ingold complet- ed a comprehensive programme of kinetic studies in- volving six series of alkyl ammonium and sulphon- ium salts.* Their elimination rates for one series and the corresponding free-energy differences are in TABLE 4.RR’CHCH,.SMe,+ +OEt-+ RR’C :CH +HOEt E2 rates (k in I.mole-l sec.-l) in ethanol at 64”. RR’CHCH RR’ 105k2 dGI (kcal./mole) Et HH 79 0 Prn MeH 29 0.67 = 0-67 Bu’ MeMe 10 1-38 = 0.67 + 0.71 Bun EtH 21 0.88 = 0.67 +0.21 BulCH PrlH 16 1-06 = 0.88 +0.18 Neohex ButH 0.43 3.49 = 1.06 +2-43 (Banthorpe et al. 1940) PROCEEDINGS Table 4. A reflexion of Smith and Frank’s orienta- tional results is obvious in these rate data. A y-carbon retards somewhat strongly and a second one equally strongly (ddG=0.7 kcal./mol.). A &carbon retards mildly and a second one equally mildly (AdG = 0.2 kcal./mol.). There again we have polar attenua- tion.But the third &carbon in neohexyl retards strongly. Obviously steric hindrance is unimportant until we reach the neohexyl structure where it enters strongly. We can make a more quantitative comparison of these and similar results with the requirements of polar theory. Hammett’s u values would naturally be thought of but so weak are the polarities that the spread of values would be too small to be useful. However other procedures can be devised. One method is to apply the simple formula= by which Branch and Calvin were able to represent the effect of the propagation of polarity in alkyl chains on the acid-strengths of carboxylic acids.g This amounts to comparing what we presume to be propagated polar effects on kinetic acidity (rate of proton loss) with what are known to be propagated polar effects on equilibrium acidity.Plots of elimination rates ex- pressed as free-energy differences against values cal- culated on these principles are shown in Fig. 3. The straight line of unit slope represents perfect agree- ment between calculation and experiment. Two N “i O+ AG:(caic) (kcaI./mole) FIG.3. Egects of homology on E2 eliminations. (Calculated by Branch and Calvin’s treatment of polar effects on acid strengths.) Hughes and Ingold Trans. Faraday SOC.,1941 37 657; Dhar Hughes Ingold Mandour Maw and Woolf J., 1948,2093. Banthorpe Hughes and Ingold J. 19?,4054, Branch and Calvin “Theory of Organic Chemistry,” Prentice-Hall New York 1941 p.201. AUGUST 1962 methods of calculation both based on Branch and Calvin's work are illustrated; but the more interest- ing set of points are those (marked with crosses) which are calculated without any disposable con- stants. One sees that the comparison with known polar effects is good except in three cases (marked N) all of which involve the neohexyl group. A theoretical calculation on quite different lines a cal- culation of steric pressures shows that this is the simplest alkyl group in which a steric retardation in bimolecular elimination would be expected. The order of magnitude of the steric effect may be roughly estimated as 2 kcal./moje and this is of the order of the observed anomaly. A more fundamental approach can be based on a method which was used by Eyring and his co-workers to calculate inductive effects on dipole moments.1° One computes charge distributions over the alkyl chains from the electric fields in the bonds taken as the sum of coulombic contributions with Slater screening from the participating atoms and from the longitudinal polarisabilities of the bonds which thanks to the LeFevres are better known now than at the time of Eyring's calculation.One gets from this an induced charge on the @-proton and a corresponding electrostatic energy in the field of the attacking anion. This energy can then be taken as the contribution of the alkyl structure to the free- energy of activation. As to numerical performance the calculation is free from disposable constants but it depends considerably on a number of inexactly known quantities; however it is reasonable to expect from it an order of magnitude and a pattern of variation of the effects of alkyl structure.In Table 5 TABLE 5. Effectsof homology on E2 eliminations from RSMe2+with OEt-. (Calculated electrostatically by Eyring's method) Alk dG$(kcal./mole) 103 dq/e Et Obs. 0 Calc. 0 (Calc.) 0 pm Bui 0.67 1.38 0.72 1-60 1.3 2.5 Bun 0.88 0.80 1.5 Bui.CH2 1-06 0.83 1.6 Neohex 3.49 0.87 1.7 the observed free-energy differences copied from Table 4 are compared with values calculated in this way. The calculated &protonic changes are included in the Table. It is clear that the calculated polarities are of a sufficient size to account for the observed kinetic effects and that the pattern of their variation is correctly reproduced except in the neohexyl example where as an independent calculation shows steric hindrance should enter uniquely and indeed to about the extent of the anomaly.I come now to the identification of the second general constitutional factor that which when dominant within a certain field involving simple alkyl substituents leads to orientation according to the Saytzeff rule. The nature of this factor was not at first apparent and did not become so until after 1935 when Baker and Nathan introduced the con- cept of hyperconjugation. This ascribed to alkyl groups not unsaturation exactly but a latent un- saturation the ability to act as if unsaturated in the presence of suitabIy neighbouring real unsaturation.It then seemed likely' that unsaturation was the general constitutional factor being sought. Unsatura- tion around the developing double bond might pro- vide the opportunity for conjugation or hyperconjuga- tion with it during its formation. That electromeric effect would produce a stabilised transition state and hence an accelerated reaction. The crudest and the simplest situation to which that idea leads is exposed if we introduce a sub- stituent which is definitely unsaturated but is as little polar as possible such as phenyl into either of the positions /3 or a from which it can conjugate with developing double bond.' Whether we work with 'onium ions or halides and whether we put the phenyl in the p-or in the a-position the main result is an acceleration of olefin formation by a factor of the order of 100.This is illustrated in Table 6 by TABLE 6. Relative rates of bimolecular elimination. RX + OEt- in EtOH at (ca.) 60". Effect of phenyl substituents. X = SMe,+ X =Br Ethyl 1 1 2-Phenylethyl 430 350 1-PhenylethyI 95 -50 (Dhar et al. 1948) some relative rates of bimolecular elimination from alkylsulphonium ions and bromides with ethoxide ions in ethanol. The fact that phenyl exerts a slightly larger accelerating effect from the 18-than from the a-position may be due to its polarity we should expect p-phenyl to have an appreciable acidifying effect on the @-proton. Within the field of simple alkyl groups our inter- pretation requires that an alkyl branch capable of hyperconjugating with the developing doublebond will accelerate its formation; that it will so act from either the @-or the a-position; and that a methyl branch will thus act more strongly than any higher homologous branch in accordance with the usual hyperconjugative order of alkyl groups.These ex- lo Smith Ree,Magee and Eyring J. Arner. Chem. SOC.,1951 73 2263; Smith and Eyring ibid. 1952,74,229. PROCEEDINGS pected effects of the potential unsaturation in alkyl forming steps are now separate. The rate-controlling groups differ in every respect from those of induced step gives a carbonium ion a portion of which is polarity in alkyl groups :the latter effects are retard- consumed in a solvolytic substitution.Thus elimina- ing are specific to the #?-position and follow the tion-rate has no simple meaning and the best inductive alkyl order with methyl as the weakest measure of the effect of alkyl structure on the ease group. All the predicted effects of latent unsaturation of olefin formation is not the rate but the propor- in alkyl structure on rate should apply just as much tion in which the carbonium ion gives olefin. It has when the structure does not admit of an orienting been shown that the unimolecular reactions of alkyl effect as when it does. In the latter case they lead chlorides bromides iodides and dimethylsulphon- to the Saytzeff rule. The Saytzeff rule should thus be ium ions with the same alkyl group in the same associated with accelerations unlike the Hofmann conditions give the same proportions of olefin.There rule which as we have seen should be and is is some evidence too though it is less well docu- associated with retardations. mented that when the alkyl group is one which gives The fulfilment of these expectations in one large a mixture of isomeric olefins the olefin composition field of application is illustrated in Table 7 with remains the same independently of the departing TABLE 7. E2 Rates AlkBr + OEt- in EtOH. (k in 1.mole-l sec.-l) Prim. Alk. #?-Substituents(55"). Alkyl Et Prn Bun n-Pentyl Bui #?-Substituent -Me Et Pr Me 105k 1.6 5.3 4.3 3.5 8.5 Sec. and Tert. Alk. P-Substituents (25"). Alkyl Pri Bus CMe,Et #?-Substituent -Me Me 107k (longer branch) 11-8 28.2 420 Sec.and Tert. Alk. a-Substituents (25"). Alkyl Et Pri Bus But CMe,Et a-Substituent -Me Et Me MeEt 107k(shorter branch) 2.5 11.8 6.5 100 85 (Hughes et al. 1941; Dhar et al. 1948) some bimolecular rates of elimination from alkyl group. Thus it should not matter and as far as we bromides with ethoxide ions in ethanol.' One now know it does not matter with which type of sub-sees rates rising in the growing alkyl chain. In the strate we illustrate;7 and in Table 8 are recorded the secondary and tertiary alkyl examples which alone 8. El olefin proportions from AlkBr in ethanol can have an alkyl-substituent at either the /%end or TABLE the a-end of the developing double bond the rates or aqueous ethanol.are analysed into component rates along the separate branches of the complete alkyl group. One sees that In 60%aqueous EtOH at 80". Pri Bus CHMePr" either a #?-methyl or an a-methyl substituent raises Alkyl the rate. So does ethyl in either position but not by #?-Substituent -Me Et 4.6 8.5 6.8 so much. In the cases of the unsymmetrically branched % Olefin groups such as s-butyl and t-pentyl one can see from In anhydrous EtOH at 25". the rates in the several branches how Saytzeff orienta- Alkyl But CMe,Et tion arises. Comparison with the lower homologous #?-Substituen t -Me isopropyl and t-butyl examples shows that there is a % Olefb (longer branch) 6.3 20-6 collaboration of effects rate in the lengthened a-Substituent Me2 MeEt branch is increased by methyl hyperconjugation and % Olefin (shorter branch) 6.3 3-3 rate in the unlengthened branches is reduced by the (Hughes et al.1941;Dhar et al. 1948) replacement of methyl by less efficient ethyl hyper- conjugation. percentages of olefin obtained in comparative con- Another large field of application is provided by ditions in unimolecular reactions of several second- unimolecular eliminations whether of alkyl halides ary and tertiary alkyl bromides containing methyl or 'onium ions. The rate-controlling and product- and ethyl substituents in their p-and a-positions. As AUGUST1962 expected both these substituents enhance the con- version of carbonium ion into olefin but from either position methyl does so more strongly than similarly situated ethyl.From the dissected figures for oleh production in the several branches of an unsymmetrical group such as t-pentyl one can see how the Saytzeff rule arises. There is a similar col- laboration of effects in the several branches though it applies now to olefin proportions and not rates. I would like to put in here a general remark on the Hofmann-Saytzeff dichotomy. It has been discussed enough to throw it quite out of perspective in the general constitutional problem. The Hofmann and SaytzeE rules even in generalised form apply only to simple unsubstituted saturated alkyl groups a very small sector of the whole range of groups in whose influence on elimination we are interested. We believe that the rules do apply in that restricted field because simple alkyl groups are unique in being in- herently destitute of those general properties on which orientation and rate of elimination depend.They have no inherent polarity but only a potential polarity actualised by induction. They have no in- herent unsaturation but only a latent unsaturation made operative by hyperconjugation. A substituent having its own intrinsic polarity will control the rate and direction of elimination independently of whether the electron-holding group is a halogen atom or an ’onium ion or anything else. A substituent having real unsaturation will control rate and orientation by conjugating with the developing ole- finic unsaturation again independently of what the departing group may be.There will be quantitative differences in the influence of these definitely polar or definitely unsaturated substituents according to the elimination system being influenced but not qualita- tive distinctions such as could be expressed in different qualitative rules. The antithetical rules apply only in the “no-man’s-land” of alkyl substi- tuents which have no properties with which to influence the elimination system apart from the properties induced in them by the system itself. So it is the system that determines what they do. Polarity and the Hofmann rule will dominate when the end-group is an ionic centre and when also as in E2 elimination in an ’onium ion not too much unsaturation is developed too early in the mechan- ism. Hyperconjugation and the Saytzeff rule will dominate when a large fraction of one electron is transferred to the departing group as to a heterolys- ing halogen in the transition state of an E2 elimina-tion so leaving the a-carbon in a highly unsaturated condition.Taft has recently shown,ll by an elegant method based on salt effects that 0.8 of an electron is transferred in the transition state of heteroIysis of 27 I t-butyl chloride in water. Hyperconjugation and the Saytzeff rule will dominate even more strongly when the whole of one electron is transferred to the leaving group before product control can begin as in any El elimination. I turn now to a relatively recent phase in the investigation of eliminations. We would like two quantitative pieces of information about any bi- molecular elimination namely the extent to which the proton is transferred from the /%carbon atom in the transition state and the extent to which the electron is transferred from the a-carbon atom in the transition state.The lesser figure will be a measure of the amount of double-bond character in the transition state. The excess of the greater figure over the lesser will measure either the amount of carbanionic charge on the /%carbon atom or the amount of carbonium ionic charge on the a-carbon atom in the transition state. The idea that even though the bond changes are coupled in the E2 mechanism either may initially outpace the other was advanced 35 years ago,3 but it is only since Cram12 recalled it seven years ago that much use has been made of it in explanation of observed phenomena.The concept of a band of E2 mechanisms differing with respect to the timing of the concerted bond changes may be exposed as follows. Any elimination may be conceptually dissected as Fig. 4 shows into t 1 /r .-‘.A C4-X 6 r+ S,I s,2 I $2 *” I -El cb €2 E-I FIG.4. an electrophilic substitution at Cp with C as the attacking electrophile and a nucleophilic substitu- tion at C with C8 as the attacking nucleophile. The Cg substitution has available the mechanisms S,l and S,2 and the C mechanisms SN2and SNl;but only three elimination mechanisms can result from the combination of these possibilities because the two bimolecular substitutions which each have only one reaction step cannot proceed unless coupled each depending on the other for its substituting agent.The still unestablished third mechanism of elimination labelled Elcb here appears as a limiting mechanism in which the proton and electron trans- fers are completely uncoupled the proton transfer completing itself before the electron transfer begins. l1 Results kindly communicated by Dr. Robert W. Taft in advance of their publication. l2 Cram Greene and DePuy J. Amer. Chem. Soc. 1955,78,790. The well known mechanism El forms the other limit in which the transfers are again uncoupled but now the electron transfer completes itself before the proton transfer begins. Between these limits stretches the "band" of E2 mechanisms in the middle region of which the transfers are strongly coupled and hence nearly synchronous whilst towards the flanks the coupling becomes weakened with one or other charge-transfer in the lead.We have not many tests with which to assess the position of any particular elimination in this con- tinuous spectrum of E2 mechanisms; and the tests we have which have been critically surveyed by Bourns13 and others particularly Bunnett,14 are not yet well developed quantitatively. But we can at least apply the available tests and see if they lead to consistent and reasonable conclusions. One test is based on the kinetic isotope effect in the separating atoms H and X. The hydrogen-isotope effect will be greatest with k,/k about 7 (unless further increased by quanta1 tunnelling) when in the transition state the proton is about half-trans- ferred and thus is under its weakest total binding.15 Any large fall in the k,/k ratio below the normal maximum would indicate an approach of the mech- anism towards one of the limits in which the proton transfer has either only just begun or is nearly finished in the transition state and so is under nearly normal binding.The X-isotope effect will behave differently because the X-group becomes free on PROCEEDINGS elimination. Hence the X-isotope effect will increase monotonically with the extent of the electron transfer in the transition state. A second test may be found in the polar demands of the eliminating system on substituents as measured by Hammett's p constants.A positive p value means that the reaction is accelerated by with- drawal of electrons from the reaction centre; and from this one may infer that an accumulation of negative charge in the transition state requires dis-persal as would happen if the proton transfer initially ran ahead of the electron transfer. Similarly a nega- tive p value means that reaction is accelerated by electron supply as it would be if in the transition state an excess of positive charge were built up because the electron transfer had taken the lead. Let us compare these two tests14 for eliminations from /?-arylethyl compounds assembling as in Table 9 the results of DePuy and of Saunders in this series.16 The order in which the expelled groups X are here arranged is approximately that of increasing electronegativity.Two charge-types are exemplified and within each the order is that of diminishing rate or increasing kinetic tightness of binding of the eliminated group X. Kinetic comparisons between the charge-types are deprived of any simple meaning by their great dependence on the solvent. Thus Hamett p values are deduced from the variations of rate with the para-substituent R; they are all positive; and they increase with the electronegativity TABLE 9. Correlation of p-values and isotope effects (Bunnett). (Measurements by Dehy and Saunders) P-R*C~H~*CH~.CH~X + OEt-HOEt p-R*CGH,*CH:CH2 Rate ratio Rate ratio Ph-CH,-CH,X Aralk.S2SMe2+ PhCD,CH2X Aralk.%Me,+ Rel.k (R = H) p 30" X ~-I Br OTs cl F SMe2+ NMe$ 26,600 +2-07 - - 4100 3-2-14 7.1 - 392 +2.27 5.7 - 68 3-2-61 - - 1 3-3-12 I - 37,900>320* +2*75 - 5.1 3.0 1 -0015 - * From a measurement (Cristol) in 92.6% ethanol. The sign > means that the rate is expected to be greater in 100% ethanol the solvent to which the other rates relate. laBuncel and Bourns,Canad. J. Chem. 1960,38,4262. l4 The remarks which follow are based essentially on a discussion kindly communicated by Dr. Joseph F. Bunnett in advance of its publication. l5 Westheimer Chem. Rev. 1961,61,265. l6 DePuy and Froemsdorf J. Amer. Chem. Soc. 1957 79 3710; Saunders and Williams ibid. p 3712; Saunders and Edison ibid. 1960,82 138; DePuy and Bishop ibid, pp.2532 2535. AUGUST1962 and tightness of binding of the terminal group X. This suggests as seems very reasonable that an in- crease in the acidifying influence of the leaving groups and an increase in the difficulty of getting rid of it allows the proton transfers to run further ahead in the successive cases so to build up suc- cessively larger transient anionic charges on the /%carbon atom. Concurrently the hydrogen-isotope effects falls. Bunnett interprets this as pointing to a half-or more-than-half-transferred proton in the transition states the extent of the transfer rising as the series is descended. We can obtain a check at one point in Saunders and Asperger's sulphur-isotope effect on the sulphonium elimination,17 which in its difference from unity is only about 10% of one they obtained in a unimolecular case; and is also about 10%of the maximum calculated from Biegeleisen's theory.Thus not much can have happened to the C,-S bond consistently with the other indications that the dominant change is in the CP-H bond in this particular transition state. The stereochemical course of eliminations pro- vides another line of evidence. It is an accepted con- sequence of regarding elimination as a combination of substituting that since SE2substitutions normally retain configuration (they certainly do in mercury- for-mercury substitutions in mercury alkyls) and since SN2substitutions always invert configuration the anti-periplanar conformation,18 shown in Fig.5 U FIG.5. Stereochemistry of eliminations as coupled substitu-tions. which these simultaneous conditions require should be a requirement of those E2 eliminations in which the bond-changes are coupled to near-simultaneity. So much evidence of such a stereospecificity usually referred to as trans-elimination in bimolecular eliminations has been forthcoming during the last 20 years,* that one is now interested mainly in the deviations. and Stermitz's E2 cis-eliminations from trans-2- p henylcyclohexyl compounds,20 as illustrated in Table 10. The normal stereochemical restriction on TABLE10. E2 cis-elimination (Cristol and Stermitz). Ph Ph I-Ph-ene necessarily formed by &-elimination. 3-Ph-ene permissively formed by trans-elimination.X Kinetic Yields isolated ('A order 1-Ph-ene 3-Ph-ene Subn. OTs Mixed* 20 53 17 SMe,+ 2 22 2 61 NMe,+ 2 64 2 8 *All the 1-Ph-ene and most of the 3-Ph-ene are expected to aiise in the E2 component of this reaction. E2 elimination requires the formation of 3-phenyl- cyclohexene only. Phenyl conjugation would favour (by a factor of the order of 100 as we have seen) the formation of 1-phenylcyclohexene ;but that involves so-called cis-elimination or elimination from a syn-clinal conformation.l8 When the separating group is toluene-p-sulphonate some E2 cis-elimination oc-curs but it is not the predominating process. How-ever when the electron-holding group is of the more acidifying 'onium type and especially when it is the difficultly detached ammonium group E2 cis-elimination becomes the dominating form of elimina- tion.One can understand that in these constitutional circumstances the C bond-change would run further ahead of the <,leading to a sufficient un- coupling of the CP and C bond charges and hence to a sufficiently reduced stereospecificity to permit phenyl conjugation to control the orientation not- withstanding that this involves a conformation far different from the anti-periplanar one normally required for E2 eliminations. We can foresee the possibility of more than a mere relaxation of the normal anti-periplanar stereo- specificity of E2 eliminations. For it has been pre- dicted21 that although all aliphatic SE2substitutions There are deviations ; and several author~l~~~~-~ for which the proof of mechanism and of steric have plausibly suggested that any marked relaxation course are both complete proceed with retention of from the normal stereospecificity is a sign of configuration such substitutions could involve in-weakened coupling and lost simultaneity of the version if only the bond to the leaving group bond changes.An example is furnished by Cristol became sufficiently ionic in the transition state. The * Oddly enough the implication of configuration-retaining stereospecificity in saturated Sd substitutions seems never to have been pointed out before. l7 Saunders and Mperger J. Arner. Chem. SOC.,1957,79 1612. Klyne and Prelog Experientiu 190 16 521. fine Wiesboeck and Ramsey J.Arner. Chem. SOC.,1961 83 1222. 2o Cristol and Stermitz J. Amer. Chem. SOC.,1960,82,4960. Charman Hughes and Ingold J. 1959,2523. application of this idea to E2 elimination is that if the proton transfer were extensive enough in the E2 transition state the involved electrophilic substitu- tion as well as the nucleophilic substitution coupled with it might involve inversion. This would produce syn-periplanar stereospecificity (so-called cis-elimina- tion). One other qualitative principle has been illustrated. It is that when an E2 mechanism is demonstrably accompanied by a limiting mechanism the variety of E2 mechanism appearing is likely to resemble closely the limiting mechanism. Hughes and Wilby suggested that this explained the fact,22 illustrated in Table 11 TABLE 1 1.E2 Saytzefl-rule eliminations (Hughes and Wilby).(y I H 4 3 3 + Me neo-El (in H,O) €2 (OH-in H20) Me Sene 2% 12% 3-ene 98% aa% that whilst the neomenthyltrimethylammonium ion easily undergoes an El elimination in water to give 3-menthene in accordance as is normal with the 22 Hughes and Wilby J. 1960,4094. PROCEEDINGS Saytzeff rule the E2 elimination of the ammonium hydroxide which may be accompanied by the El reaction and is indeed difficult to free from it completely gives on its own account 88% of 3-menthene also in accordance as is quite abnormal with the Saytzeff rule. Hughes and Wilby assumed that for a special constitutional reason the C,-X bond change is in this particular E2 reaction ab- normally advanced beyond the Cp-H bond change the timing having a qualitative similarity to the un- coupled timing in the accompanying El process.This would imply the development of considerable carbonium ionic character and hence of unsatura- tion on C in the transition state so giving control to the Saytzeff rule. The special constitutional cir- cumstance which was thought to give rise to these effects was instability in the initial state due to steric pressure between the &related isopropyl and tri- methylammonium groups. Reaction mechanisms in general are elucidated in successive approximations. The relative timing of concerted bond changes should represent the next major stage in the study of several general reactions of which elimination is one of the simplest.Up to the present only reconnaissance work on it has been done. CHEMICAL SOCIETY COMBINED POOL OF TRUST INVESTMENTS THEnotice printed below is published at the request of the Charity Commissioners. On August 23rd 1960 the Charity Commissioners established a scheme whereby the investments of the individual trust and lecture funds administered by the Society were consolidated into a combined pool. The income arising from these investments is divided in propor- tion to the value of the assets which each fund con- tributed to the pool at the date of consolidation (Proceedings 1961 39). Since the scheme was established the Society has acquired two additional trust funds the Ethel Behrens Fund and the Robert Robinson Lecture Fund.The Charity Commissioners now propose at the request of the Council to establish a scheme the main purpose of which is to allow the investments of these new charities to be consolidated into the pool. The two trusts will retain their separate identities but will receive income from the pool appropriate to the assets contributed at the date when they are incor- porated. The scheme also provides that the endowment of any charity of which the Society become the trustee in the future may be added to and form part of the combined pool of trust investments. The Council is of the opinion that this scheme will simplify the administration of the funds and enable each fund to hold a properly balanced group of investments.CHARITY COMMISSION The Ethel Behrens Fund and The Robert Robinson Lecture Fund administered by The Chemical Society. Scheme to include the Charities in The Chemical Society Investment Pool. The Charity Commissioners propose to establish a Scheme for this and other purposes. Copies of the proposed Scheme will be supplied on written request to the Charity Commission 14 Ryder Street London S.W.1 (quoting ref. No. A.129779) and may also be seen at that address. Objections and suggestions may be sent to the Commissionerswithin one month from today. AUGUST 1962 275 PROCEDURE FOR THE ELECTION OF FELLOWS of FELLOWSthe Society resident in the United Kingdom will have received a formal notice con- vening an Extraordinary General Meeting called to consider a resolution proposing changes in the Bye- Law which describes the procedure for the election of Fellows.At present the Bye-Laws require that new applica- tions for Fellowship should be considered by the Council of the Society only after the names and addresses of the applicants have been published in Proceedings. The Council feels that this system in- creases printing costs and causes unnecessary delay to bona fide applicants without providing an en- tirely satisfactory protection against the election of unsuitable candidates. If the motion to be put to the meeting is adopted the names will not in future be published but a list of candidates will be displayed in the rooms of the Society for twenty-eight days prior to the meeting of Council at which the applications are to be con- sidered.The Council believes that this new pro- cedure is in line with the practice generally adopted by many other learned and professional bodies. However as an additional safeguard it is proposed that a small committee should be appointed to scrutinise the applications before they are voted upon by the full Council. COMMUNICATIONS The Influence of Pre-irradiation Treatment on the Chemical Effects of the 35Cl (rt,~)~~S Reaction in Alkali Chloride Crystals By A. G. MADDOCK and R. M. PEARSON (THECHEMICAL LENSFIELD LABORATORIES ROAD,CAMBRIDGE) 1~ is well known that the %Sformed by the neutron irradiation of sodium or potassium chloride crystals in air is found after dissolution of the crystals in water containing sulphide sulphite and sulphate carriers almost entirely in the sulphate fracti0n.l Koski2 has shown that if the crystals are exhaustively outgassed at 500-600" and then irradiated in vacuo the 35S appears in the sulphide fraction.Exposure of such crystals to air soon converts the 35S into the sulphate state and Koski suggested that this oxida- tion is due to molecular oxygen diffusing into the alkali chloride lattice3 More recently Chemla has found that the process of oxidation actually involves the movement of the 35S towards the surface of the crystallites.4 Some earlier observations5 on rubidium chloride showed that the 35S may not always be as readily oxidised and one of the present authors has sug- gested a mechanism for this process.6 This mechan- See e.g.Croatto and Maddock J. 1949 S 351. Koski J. Amer. Chem. Sac. 1949,71 4042. Koski J. Chem. Phys. 1949 17 582. ChemIa Compt. rend. 1951,232 1553,2424. ism implies that interference with the ready diffusion of the 35Swill tend to stabilise the S2-form. We have found that defects introduced into the alkali chloride lattice by any of three well-established techniques lead to a high 35S2- 35S0,2- ratio and the 35S2- in these crystals undergoes aerial oxidation to sulphate far less readily. We find that introduction of 10-4-10-5 mole frac- tion of calcium or cadmium chloride into potassium chloride crystals increased the 35S2- content to as much as 57% after irradiation of the crystals in air.A control sample of pure potassium chloride gave < 1% of 35S2-. Such doped crystals contain cation vacancies. Pre-irradiation of sodium chloride crystals with ionising radiation is known to create Fand Ycentres and their derivatives. We found that pre-neutron irradiation with doses of 2-Mev electrons of 10 20 and 100 Mrad to lead to 58.2 77-0 and 88-1% Karnen Phys. Rev. 1941 60 537; Croatto and Maddock Nature 1949 164 613. Maddock Proc. Symposium on Chemical Effects of Nuclear Transformations J.A.E.A. p. 214. Vienna 1961 Vol. 11 respectively of %S2-. These results were obtained with crystals irradiated with neutrons in air. Finally some sodium-enriched crystals were pre- pared by heating single crystals grown from melts in sodium vapour.The product was blue indicating that colloidal sodium was already present. The per- centage of %S2- was very high even after neutron irradiation in air a dark blue crystal contained 946% and a medium blue crystal contained 90.1 % PROCEEDINGS of %S2-. Storage of the neutron-irradiation cadmium- doped crystals for two weeks in air gave no measur-able change in %S2-content but crushing these crystals in air reduced the percentage of %S2-from 34% to 22%. It is clear that the behaviour of %S is profoundly affected by the defect density and possibly by the nature of the defects in the crystals that are irradiated. (Received July 9th 1962.) Ion-Sieve Properties of Zirconium Phosphate By C.B. AMPHLETTand (Miss) L. A. MCDONALD (CHEMISTRY BERKS) DIVISION,A.E.R.E. HARWELL THE marked resistance to swelling on immersion in water shown by zirconium phosphate suggests that it may possess ion-sieve properties resembling those demonstrated for the zeo1ites.l Such a property might provide a useful determination of pore sizes since the use of X-ray methods is precluded by the poor degree of crystallinity. Samples of zirconium phosphate have been equi- librated at room temperature with 0.IN-solutions of substituted alkylammonium salts and the uptake measured at equilibrium; saturation capacities have also been determined by repeated batch equilibration until no further uptake occurred.The results are shown in the accompanying Table normalised to the values for the ammonium ion. Inspection of the results for the tetra-alkylammonium ions shows that both equilibrium uptake and saturation capacity de- crease with increasing ionic size; while the former effect could be due to a decrease in affinity resulting from the lower charge density the latter can only be explained on steric grounds and must result from a fraction of the pores being too small to admit the larger cations. A steric effect is also observed in the monoalkylammonium ions as the chain length of the substituent increases; since the minimum dimension of the cation is unlikely to change appreciably as the chain length is increased (provided that the chains are not coiled) this suggests that exchange sites within the pores are blocked by the alkyl chains.This is supported by the fact that when the results are plotted as a function of chain length the points for the two dialkylammonium ions fall on the same smooth curve as those for the monoalkylammonium ions using equivalent chain lengths of six and eight carbon atoms respectively. The lower capacity shown by isopropylammonium compared with n-propyl- Barrer Proc. Chem. SOC.,1958 102. Kressman and Kitchener J. 1949 1208. Quilibrium uptake (U) saturation capacity (C) and equilibrium uptake corrected for reduction in capacity (U,) for substituted alkylammonium ionson zirconium phosphate relative to values for ammonium ion. Cation U C uc MeNH,+ 0.82 0.80 1.02 EtNH,f 0.78 0.74 1.05 PrnNH3+ 0.68 0-72 0.94 PriNH3+ 0.68 0.63 1-09 BunNH3+ 0.62 0-57 1.09 PenNH3+ 0.56 0.56 1-00 Pm2NH2+ 0.50 0.50 1.00 BunSNH2+ 0.39 - NMe,f 0.72 0-56 1.27 NEt,+ NBU,' 0.53 0.30 0.43 - 1.23 - ammonium is probably due to the increased diameter of the former.To a first approximation we may correct the up-take figures for steric effects and so obtain relative affinities by dividing the former by the capacity to give the figures in the final column. These show the uptake to be roughly independent of chain length in the alkylammonium series suggesting that the charge density is determined almost entirely by the terminal ammonium group. The corrected values for tetra- alkylammonium ions although less extensive show the affinities to be greater than that for ammonium; a similar result found for a phenolsulphonic acid resin2 was ascribed to the participation of non-Coulombic forces (van der Waals or induced ion- dipole attraction).These and other results indicate the possibility of using this approach to gain information on the structure of this class of ion-exchange materials. (Received June 26th 1962.) AUGUST 1962 277 Osmium Oxide Pentafluonde OsOF By NEIL BARTLETT N. K. JHA and J. TROTTER OF CHEMISTRY OF BRITISH (DEPARTMENT THE UNIVERSITY COLUMBIA VANCOUVER 8 B.C. CANADA) THE fluorination of osmium dioxide or of osmium orthorhombic modification (low-temperature form) in the presence of oxygen gives a mixture of fluorides of the hexafluorides of rhenium,2 osmium iridium A complete structure determination from which a volatile paramagnetic emerald green and platin~m.~ solid m.p.59.8” can be isolated readily. This has has been undertaken to determine the extent of the been shown to be osmium oxide pentafluoride which octahedron distortion associated with the hetero- we believe to be the first Os7f compound (Found ligancy. F 31.1. OsOF requires 31.5%). The solid is stable The ease of formation of the oxyfluoride together in dry air but hydrolyses rapidly in moist air and with the apparent absence of hepta- or octa-fluoride reacts rapidly with water with the evolution of ozone- point to the oxidation state limit being imposed by a smelling gases and formation of osmium tetroxide.ligancy maximum of six. Seven- or eight-co-ordina-Precession and Weissenberg photographs of a tion in osmium complexes has not been confirmed. single crystal mounted in a thin-walled quartz capil- The only other seven-positive six-co-ordinate lary show the solid to be orthorhombic at 23” f2” species reported hitherto4 is rhenium oxide penta- with a = 9-540 f0.004,b = 8.669 f0.004 c = fluoride which should be isostructural with the 5.019 f 0.004 A; V = 415.1 A3;2 = 4. There are osmium compound. Neither iodine oxide penta- no general absences of hkl reflexions but for OH,k + fluoride nor technetium oxide pentafluoride is known. = 2n and for hkO h = 2n. Space groups Pnma (Dii No. 62) and Pn2,a (C,”,,No. 33) satisfy these We thank the Research Corporation and the conditions.National Research Council Ottawa for generous Osmium oxide pentafluoride is apparently iso- financial assistance and the latter also for a scholar- morphous and nearly isostructural with the actinide ship (to N.K.J.). hexafluoridesl (space group Pnma) and with the (Received June 29th 1962.) Hoard and Stroupe 1944 Cornell Report A-1296; “Chemistry of Uranium Collected Papers,” TID-5290, U.S.A.E.C. Technical Information Service Extension Oak Ridge Tennessee Book 1 pp. 325-350;Zachariasen “The Transuranium Elements,” Ed. Seaborg Katz and Manning Plutonium Project Record N.N.E.S. Div. IV Vol. 14B, McGraw-Hill New York 1949,p. 1465;Florin Tannenbaum and Lemons J. Inorg. Nuclear Chem. 1956,2 368. Malm and Selig J. Inorg.Nuclear Chem. 1961,20 195. Weinstock Malm and Weaver J. Amer. Chem. Soc. 1961,83 4310. 4 Aynsley Peacock and Robinson J. 1950 1623. A New Type of 1,2-Shift By R. M. ACHESONand J. M. VERNON (DEPARTMENT UNIVERSITY OF OXFORD) OF BIOCHEMISTRY the 1 -methylpyrrole-dimethyl acetylenedi- place. Reductive debromination of this last indole HEATING with palladised charcoal to gave (11) thereby establishing the structural skeleton. carboxylate adductl (I) ca. 200” caused aromatisation to the indole (11)and The reactions of the isomer strongly suggest that a formation of variable amounts of an isomer (IV) of benzene ring is present and that further aromatisa- the original adduct. In contrast to (I) the isomer tion through loss only of hydrogen atoms is impos- could be neither reduced nor induced to react with sible.The isomer has an ultraviolet absorption dimethyl acetylenedicarboxylate and it was stable to spectrum very similar to that of methyl m-dimethyl- silver oxide in boiling light petroleum. With bromine aminobenzoate and its nuclear magnetic resonance in methanol which converts1 the adduct (I) into the spectrum includes absorption due to four ester-indole (II),the isomer yielded a monobromo-substi- methyl and one N-methyl group and also to one tution product which on hydrogenation over pal- isolated proton at 7 4.7. If a benzene ring is present ladium on charcoal regenerated the isomer. An acid the isolated proton can only be at position 2 as a obtained from the bromo-derivative by alkaline proton at position 3 would not be sufficiently de- hydrolysis gave a trimethyl bromo- 1-methylindole-shielded; the isomer must therefore possess structure tricarboxylate with diazomethane oxidation and (IW.loss of carbon dioxide presumably having taken Partial aromatisation of the adduct (I) to the 1 Acheson Hands and Vernon Proc. Chem. SOC.,1961 164; Acheson and Vernon J. 1962 1148. isomer (IV) may occur through nucleophilic attack of the 3 position at the 3a-carbonyl group leading to the intermediate (111). Opening of the three-membered ring and movement of the 7a-hydrogen -0,,OMe Mew qMeCOMe @:g * Me (m> 0 v> Me PROCEEDINGS atom complete the sequence which accounts for the “1,2-shift” of the ester group. The intermediate (111) is similar to the cyclopro- panone intermediate suggested2 for the Favorskii rearrangement.It is also possible that in this base- catalysed rearrangement an anion adds to the car- bony1 group giving an intermediate comparable to structure (111). Analogies are also apparent with the 1,3-shift of an ester group in the abnormal Michael rea~tion,~ and with the Stevens rearrangement.4 We are indebted to Dr. E. 0. Bishop for the nuclear magnetic resonance measurements to the D.S.I.R. for a studentship (J.M.V.) and to Dr. J. W. Cornforth Dr. A. Pelter and Professor G. W. Wheland for correspondence. (Received,July 3rd 1962.) Loftfield J. Amer. Clzem. SOC., 1951 73,4707. Bergmann Ginsburg and Pappo Org. Reactions 1959 10 179. * Hauser and Kantor J.Amer. Chent. SOC.,1951 73 1437. Kinetic Evidence for Association in Displacements at Platinum(r1) By PAUL HAAKE (GATES LABORATORIES CALIFORNIA OF TECHNOLOGY, AND CRELLIN OF CHEMISTRY INSTITUTE PASADENA CALIFORNIA ;AND DEPARTMENT OF CHEMISTRY UNIVERSITY OF CALIFORNIA Los ANGELES) A MECHANISM involving association of nucleophile with complex has been suggested1 as part of the mechanism of displacement at platinum(@. We have studied the displacement of chloride ion in the re- action of NO2- with cis-Pt(NH,),Cl,. The reaction involves two consecutive displacements ; rate con- stants for both steps can be evaluated by inspection of the rate data obtained by potentiometric titration of chloride ion. The kinetics were done with excess of NO2- so that first-order rate constants were ob- tained in all runs.The rate constants for displace- ment of the second chloride are non-linear in con- centration of NO2- falling off at high concentration. This kinetic dependence may be explained by reac- tions (1) and (2) the second being the rate-determin- ing step. cis-Pt(NH,),(NO,)Cl + K NO1 + [Pt(NHd2(NO&&l]-(1) k [Pt(NH3)2(N02)2Cl]-cis-Pt(NH3)z(N02)2+ c1-(2) If this scheme is correct eqn. (3) should provide a linear relation from which the equilibrium constant for reaction (1) and the rate constant for reaction (2) can be determined.2 This linear relation gives K = 33 mole-l 1. and k = 18 x sec.-l. The accuracy of the rate constants for displace- ment of the second chloride were checked spectro- photometrically at 260 mp ; the dinitro-complex shows a larger extinction coefficient at this wave- length than either the chloronitro- or dichloro-complexes.The existence of a transient intermediate was confirmed by an immediate enhancement of optical density on adding NO2- to solutions of cis-Pt(NH,),(N02)C1. This must have been due to the intermediate in reaction( 1) since theincreasein optical density occurred too quickly to be due to formation of the dinitro-complex. The magnitude of the in- crease in optical density again showed non-linear dependence on concentration of NO2-. Thus there is good kinetic and spectral evidence for association between NO and cis-Pt(NH,),(NO2)C1. Although there is no direct proof it seems reason- able that the associated species is an intermediate in the displacement of chloride ion.In agreement with current theories of bonding at platinum(II),lb this (a) Basolo Chatt Gray Pearson and Shaw J. 1961 2207; (b) Basolo and Pearson “Mechanisms of Inorganic Reactions,” Wiley New York 1958 Ch. 4. Duke and Bulgrin J. Amer. Chem. Soc. 1954 76 3803. AUGUST 1962 279 intermediate is probably a tetragonal pyramid (I) group at the apex;3 a trigonal bipyramid might with the nucleophile at the apex. The rate-determin- represent a stable configuration during this re-ing step may be a rearrangement of (I) to form arrangement. another tetragonal pyramid (II) which has leaving NO2 The author thanks Professor G. S.Hammond for H,N-...I /C' H,N. .. /NO2 helpful discussions and the California Institute of ,Pi( .Pt*' Technology for an Arthur Amos Noyes Post-H,N NO2 H,N(IC1'NO* doctoral Fellowship. (1) (a) (Received,June 8th 1962.) Pearson J. Chem. Editc. 1961 38 171. a-Hydroperoxides of Ketones and Esters by Autoxidation in Alkaline Media By H. R. GERSMANN and A. F. BICKEL H. J. W. NIEUWENHUIS (KONINKLIJKE/SHELL-LABORATORIUM, AMSTERDAM) A RECENT publication1 on the preparation of can be considerably enlarged by the use of solid a-hydroperoxy-esters by autoxidation of esters in potassium t-butoxide suspended in an aprotic solvent pyridine-benzyltrimethylammonium hydroxide (e.g.,glycol dimethyl ether toluene). This base allows prompts us to report results obtained in our investi- the autoxidation of a large number of ketones and gation of the autoxidation of ketones and esters in a esters to proceed very rapidly at low temperature.In medium containing potassium t-butoxide. many cases the reaction temperature can be so low This base in t-butyl alcohol has been ~sed~?~ that these compounds can even be isolated in good for the autoxidation of ketones aldehydes and esters. yield (Table 1). The successful iso'lation of the TABLE. Formation of hydroperoxides in autoxidations of ketones and esters. I Substance (mole) K t-butoxide Solvent* Temp. Time Conversion Yield (%)t (mole) (d.) (min.) (%I Di-isopropyl ketone 0.1 0.18 500 A -5" 45 100 78 50 Isopropyl methyl ketone 0.12 0.18 500 B -8 35 84 83 40 Is0butyrophenone 0.1 0.4 500 c -75 60 85 50 - p-Methoxyisobutyrophenone 0.05 0.2 4OoC -75 5 85 85 50 t-Butyl isobutyrate 0.07 0.2 400 c -10 15 55 50 30 t-But yl phen ylace ta t e 0.03 0-1 300 c -75 3 85 80 55 Ethyl phen ylacetate 0.04 0.1 300 c -75 3 90 40,-1 * A t-Butyl alcohol-ethyleneglycol dimethyl ether (2:3 v/v).B t-Butyl alcohol-ethylene glycol dimethyl ether (1 :1 v/v). C Ethylene glycol dimethyl ether. 7 The first value is that estimated by iodometric titration the second that isolated by ether extraction of the carefully neutralised cold autoxidation solution and subsequent distillation in high vacuum and/or crystallisation. $ Not isolated. Although Doering and Haynes2 assumed these re- cc-hydroperoxide of phenylacetic acid indicates that actions to proceed via cc-hydroperoxide intermediates our oxidation system is suitable in principle for the the presence of these compounds could not be preparation of secondary hydroperoxides.These demonstrated. However a-hydroperoxides of 20-compounds are convenient starting materials for keto-steroids have recently been isolated4 from the a-0x0-acid esters.* The use of t-butyl esters in the products of autoxidation in t-butoxide-t-butyl t-butoxide system is not essential since transesterifi- aico hol. cation is insignificant. We have found that the scope of this autoxidation (Received June 14th 1962.) * Phenylglyoxylic and mandelic esters are actually formed as by-products in the autoxidation of phenylacetic ester. Avramoff and Sprinzak Proc. Chem. SOC.,1962 150. Doering and Haines J.Amer. Chem. SOC.,1954 76 482. Elkik Bull. SOC.chim. France 1959,933. Bailey Elks and Barton Proc. Chem. Soc. 1960 214. PROCEEDINGS Synthesis of Epicyclocolorenone and Stereochemistry of Cyclocolorenone By G. BGCHI and H. J. E. LOEWENTHAL OF CHEMISTRY INSTXTUTE (DEPARTMENT MASSACHUSETTS OF TECHNOLOGY CAMBRIDGE, MASSACHUSETTS) CYCLOCOLQRENONE, a sesquiterpene ketone from CCI,). Addition of hydrogen bromide to this ketone Pseudowintera colorata was assigned structure (I) followed by treatment with methanolic potassium without stereochemistry.l We have confirmed this by hydroxide9 led to a mixture of products from which synthesis of its 1-epimer (11) and suggest (I) as the epicyclocolorenone (11) m.p. 65-5-67" [a], complete structure.-167" Amax. 253 mp (E 9300) Vmax. 1695 1627 prepared from cm.-l (CCI,) could be isolated by chromatography. The known dien~ne-lactone,~~~ 0-acetylisophotosantonic acid lactone (111; R = Ac),~~, was reduced with chromous chloride in acetic acid to the acid (IV) m.p. 110-1 ll" Amax. 305 mp (E 15,400) (all in MeOH) [aID + 10804 (all in CHCl,). Partial reduction in either neutral or basic medium gave mainly an acid (V; R = CO,H) m.p. 136-137" Amax. 242 mp (E 14,600) and smaller amounts of its isomer (VI) m.p. 142' Amax. 243 mp (E 13,600) identical with an acid prepared by selective hydrogenation of the dienone (VII) followed by re- duction with chromous chloride. Both acid (VI) and lactone (In) exhibited a positive Cotton effect where- as the isomer (V; R = C0,H) showed a negative curve.Furthermore a nuclear magnetic resonance spectrum (CDCI,) of the acid (V; R = C0,H) possessed a doublet at 9.057 (J 7 clsec.) which was shifted to 9-357 (J 7 c/sec.) in its isomer (VI). Dreid-ing models show that the 10-methyl group is situated above the plane of the double bond5 in isomer (VI) but not in the other (V; R = CO,H) and these findings agree only with the revised configuration of isophotosantonic acid lactone (111; R = H).6 The ester (V; R = CO,Me) m.p. 77.5-79' was reduced with lithium aluminium hydride to a mixture of Natural cyclocolorenonelO (Amax. 262 mp E 16,200) crystalline diols which on re-oxidation with 2,3& was epimerised by passage in pentane solution chloro-5,6-dicyanobenzoquinonein dioxan' fur-through Woelm alumina (activity I) or by treatment nished the 0x0-alcohol (V; R = CH2.0H) m.p.with alkali.ll The product (II) m.p. 65-67" [aID 51-53 ". Treatment of its bromobenzene-p-sul-162' and was identical with synthetic material phonate with dimethylamine in acetonitrile gave the (infrared spectra and mixture m.p. determination). amino-ketone (V; R = CH,.NMe& m.p. 48-5-49' A hypsochromic shift in the ultraviolet spectrum (negative Cotton effect) whose N-oxide on pyrolysiss accompanying this epimerisation indicates less yielded the liquid ketone (V; R = CH,:) Amax efficient cyclopropane ring-double bond interactionfa 244 mp (E 13,600) Ymax. 1700 1640 895 cm.-l (in in epicyclocolorenone (11) and is in perfect agreement Corbett and Speden J.1958 3710. a Barton de Mayo and Shafig J. 1957 929. Arigoni Bosshard Bruderer Buchi Jeger and Krebaum Helv. Chim. Acta 1957 40 1732. This substance was also prepared by Barton Levisalles and Pinhey J. in press. Jackman "Applications of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry," Pergamon Press, New York 1959 p. 129. Asher and Sim Proc. Chem. Soc. 1962 111; Barton Miki Pinhey and Wells Proc. Chem. Soc. 1962 112. Burn Petrow and Weston Tetrahedron Letters 1960 No. 4 14. Cope and Trumbull Org. Reactions 1960 11 317. Bates Buchi Matsuura and Shaffer J. Amer. Chem. SOC.,1960 82 2327. lo We wish to express our gratitude to Dr. R. C. Corbett for making available a generous sample of pure cyclo- colorenone.l1 Dr. Corbett informed us that he had observed the base catalysed isomerisation of cyclocolorenone some time ago and his unpublished work consequently deserves priority. la Kosower and Ito Proc. Chem. Soc. 1962,25. AUGUST 1962 with deductions from the scale model. Cyclo-colorenone (I)has an abnormally shielded 10-methyl group (doublet at 9.257 J 6clsec.) attributable again to shielding by the double bond. In its epimer (11) the proton at C1,is diamagnetically shifted and the methyl group is now part of an AB system' with broad absorption at 9-07 merging with one of the methyl singlets. Finally the ketones (I) and (I0 l3 Corio Chem. Revs. 1960,60 363. 28 I exhibit mass spectra which differ only in the relative intensities of a few peaks.The authors are grateful to the National Science Foundation and to Fimenich and Cie Geneva for generous financial support. Rotatory dispersion curves were kindly measured by Professor W. Klyne (London). (Received July 2nd 1962.) New Syntheses of Hexafluorobenzene By R. E. BANKS R. N. HASZELDINE, J. M. BIRCHALL J. M. SIMM,H. SUTCLIFFE and J. H. UMFREVILLE (FACULTY UNIVERSITY OF TECHNOLOGY OF MANCHESTER) SEVERAL routes to hexafluorobenzene and other poly- fluoro-aromatic compounds have been reported in recent years,14 but all of these are either tedious or expensive to operate on a large scale. The pyrolysis of tribromofluoromethane,lS2from which yields of up to 55% of hexafluorobenzene are obtained is simple and its only drawback is the removal of the relatively large amounts of bromine liberated by the pyrolysis; although tribromofluoromethane is not a commercial chemical its preparation from carbon tetrabromide is not difficult.The formation of hexafluorobenzene by pyrolysis of the readily available and comparatively cheap di-chlorofluoromethane or by pyrolysis of the readily prepared dibromofluoromethane is now reported 6CHFX -+ CsF + 3X + 6HX (X = CI or Br) The formation of hexafluorobenzene by this route probably involves formation of the fluorohalogeno- carbene as an intermediate but not that of the olefin CFX :CFX since separate experiments show that pyrolysis of 1,2-dichlorodifluoroethylene gives no hexafl~orobenzene.~ Dichlorofluoromethane was pyrolysed in an atmosphere of nitrogen over a platinum surface at 600-800" in the apparatus described previously.2 The liquid products were analysed by gas-liquid chromatography and hexafluorobenzene was identi- fied by its retention time and by infrared spectro- scopy.Appreciable amounts of hexafluorobenzene (> 5 %) were obtained at temperatures in the range 700-750" with contact times of 04-8-0 sec. Thus a yield of 9% was obtained at 750" with a contact time of 3-3 sec. Under these conditions which are not considered to be necessarily the optimum no dichlorofluoromethane remained unchanged and other products included hydrogen chloride trichloro- fluoromethane 1,2-dichlorodifluoroethylene and tetrachloro-1,Zdifluoroethane.Dibromofluoromethane prepared in good yield by the fluorination of bromoform with antimony trifluoride? was pyrolysed at 555-765" with contact times of 2-20 sec.; hexafluorobenzene was pro-duced in appreciable yield (> 10%) in the range 665-765'. A 33 % yield was obtained at 715" with a contact time of 9 sec. and this yield is expected to be improved. Pure hexafluorobenzene was isolated from the products of both series of pyrolyses by preparative gas-liquid chromatography. The authors are indebted to Pennsalt Chemicals Corporation for a grant in support of this work. (Received July 3rd 1962.) ' DCsirant Bull. Soc. chim. beiges 1958 67 676; Hellmann Peters Pummer and Wall J. Amer. Chem. Soc. 1957 79 5654. Birchall and Haszeldine f.,1959 13.Birchall Haszeldine and Parkinson f.,1961,2204. Godsell Stacey and Tatlow Nature 1956 178 199; Stephens and Tatlow Chem. and fnd. 1957 821 ; Gething, Patrick Tatlow Banks Barbour and Tipping Nature 1959 183 586; Gething Patrick Stacey and Tatlow ibid. p. 588; Coe Patrick and Tatlow Tetrahedron 1960,9,240; Mobbs and Musgrave Chem. and Znd. 1961 1268. Swarts Bull. Classe Sci. Acad. roy. Belg. 1910 113. PROCEEDINGS A Convenient Synthesis of Some Tropone Derivatives By A. J. BIRCHand J. M. H. GRAVES (UNIVERSITY OF MANCHESTER) and F. STANSFIELD (UNIVERSITYKHARTOUM) OF RECENTLY,~ 1 -ethoxycyclohexene has been converted hydroxytropones cannot be made directly by this through its dichlorocarbene adduct into cyclo-route the method is the most convenient at present heptadienone.We have developed a similar method available for tropone syntheses. which conveniently leads to tropone and some tro- pone derivatives. 2,5-Dihydroanisoles are readily obtained2 by reduction of anisoles by means of sodium and ethanol in liquid ammonia. These react preferentially with dichloro- or dibromo-carbene at the enol-ether double bond. For example 2,5-di- hydroanisole (I; R = H) with 1.2-1-5 moles of halogenocarbene gives first the adduct (XI; X = C1 or Br R = H) in essentially quantitative yield except for a small proportion of the bisadduct (111; X = C1 m.p. 100-101"; X = Br m.p. 138") which can be obtained in higher yield by using more halogeno- carbene. The structure of the monoadducts is sup- 2,3-Dihydr~anisole~reacts with dichlorocarbene ported by disappearance of the enol-ether band less specifically at the substituted double bond and a [vmax.1686 cm.-l for (I; R = €3) and 1710 cm.-l for mixture is obtained containing about 20 % of (IV) as (I;R = OMe)] and lack of hydrolysis with mild acid. shown by the infrared spectrum (vmaX. 1684 cm.-l) These adducts are rather unstable and have usually and by mild hydrolysis to the corresponding ketone. been employed directly. The action of hot aqueous Unlike the derivative (11; R = H X = C1) which is silver nitrate on (11; X = C1 R = OMe) [from stable to acid the adduct (V) is converted directly by 3,6-dihydroveratrole(I; R = OMe)] gave 3-hydroxy- boiling 2~-methanolic hydrochloric acid into tropone tropone (65 % yield) having properties in accord with (35% yield based on dihydroanisole).In this case the 1iteratu1-e.~ Similar treatment of 01; X = C1 the reaction leading to fission of the cyclopropane R = H) resulted chiefly in recovery of starting ring is presumably initiated by protonation of the material but (11; X = Br R = H)gave tropone conjugated double bond. (75 % yield).4 Apart from limitations on structure e.g. 2-(Received June 1 Srh 1962.) Parham Soeder and Dodson J. Amer. Chem. Soc. 1962 84 1755. Birch Quart. Rev.,1950 69. Chapman and Fitton J. Amer. Chem. SOC.,1961 83,1005; Johns Johnson and Tisler J. 1954 4605. Dauben and Ringold J. Amer. Chern. Soc. 1951 73,876; Doering and Detert ibid. 1951 73,876. Birch J. 1947 1642.a-Sulphanuric Chloride By A. J. BANISTER and A. C. HAZELI. OF CHEMISTRY NEWCASTLE (DEPARTMENT KING'S COLLEGE UPON TYNE,1) THE potential aromatic character of the cyclic a-compound has also been prepared by two other phosphonitrilic halides and the thiazyl halides has Structures (I) and (TI) were proposed for been recognised for some time and has been dis- it by Kirsanov? On the basis of physical properties cussed in detail? Sulphanuric halides belong to another potentially aromatic inorganic system. Cl\ /N $0 CL,&+,y\+?.,/,o From the pyrolysis products of trichlorophos- 09' ?Yl N;+-N 1 phazosulphuryl chloride Kirsanov2 isolated two <I a' (a) c,,xo substances (a and /3) of formula (NSOCl),. The N*S" "0 Craig Chem. SOC.Special Publ.1958 No. 12 p. 343; Craig J. 1959 997. Kirsanov J. Gen. Chem. (U.S.S.R.) 1952 22 93. Goehring Heinke Malz and ROOS,Z. anorg. Chem. 1953 273,200. Goehring and Malz 2.Naturforsch. 1954 9b 567. AUGUST1962 he suggested that the a-compound was trans- and the /3-compound was the cis-sulphanuric chloride. Q This implies a planar ring. The results reported in this paper show that this is not so. We have prepared a-sulphanuric chloride by a modification5 of Kirsamv’s procedure and studied it by X-ray analysis. The crystals are orthorhombic of space group Pnma with four molecules in the unit cell of dimensions a = 7-60,b = 1 1 *46,c = 10.10A. A three-dimensional refinement to a discrepancy factor of 16% gives bond lengths S-N = 1-58 S-C1 = 2-00,S-0 = 1.43A.The arrangement of the bonds round the sulphur is roughly tetrahedral.The must occur as discussed by Craig’ for six- and eight- S-N-S angles are 120” and so formula (11) con- membered rings with alternating single and pn-dn. tributes insignificantly to the overall molecular struc- double bonds. ture. The molecular symmetry is 3m = Csvwithin experimental error. The chlorine atoms are all axial The calculations were carried out on the Durham (see Figure). The compound therefore has one of the University Pegasus computer with programmes de- four possible chair forms. vised by Dr. D. w. J. Cruickshank and Miss D. E. Since the sulphur-nitrogen bond distances are Pilling and by Dr. P. A. Samet. One of us (A.C.H.) identical within experimental error and close to the thanks British Titan Products for a Research double-bond distance (1-56 A)predicted from con- Fellowship.ventional radii,6 delocalisation of the n-electrons (Received June 14th 1962.) Banister unpublished work. Pauling “The Nature of the Chemical Bond,” Cotnell Univ. Press New York 3rd edn. pp. 224 228. The Reaction of Sodamide with $-Acetylenic Acids and Their Derivatives By J. CYMERMAN CRAIG and M. MOYLE OF PHARMACEUTICAL UNIVERSITY SANFRANCISCO (DEPARTMENT CHEMISTRY OF CALIFORNIA 22) WEreported1 the smooth conversion of a series of lost both ester groups giving 1,1,4,4-tetraphenylbut- diethyl vinyl phosphates (I) into the corresponding 2-yn-1,4-dioP (24%; m.p. 192”). Under the same acetylenes (II) on treatment with sodamide in liquid conditions both ethyl propiolate (IIb) and trans-l,2- ammonia.While trans-2-ethoxycarbonyl-1 -phenyl-diethoxycarbonylvinyl diethyl phosphate (Ib; b.p. vinyl diethyl phosphate (Ia) gave phenylpropiolamide 125-127”/0~005 mm.; nE5 1.4470) afforded the same (72%) at -70° the same reactants at -33O afforded diol in the same yield. only phenylacetylene (mercury salt2) in 75 % yield. (I) RC:CHR’ (11) RC:CR’ Phenylpropiolamide (formed by the action of an- (a) R =R =C02Me I hydrous ammonia on ethyl phenylpropiolate) on O.PO(OEt) (6) R =H R =C02Et treatment with sodamide in liquid ammonia at (a) R =Ph R’ =C0,Et (c) R =But R’ =CO-NH, -33O was similarly completely transformed into phenylacetylene and urea (identified as dixanthydryl- (b) R =R =C02Et urea3);phenylpropiolic acid was not formed.4,4-Dimethylpent-2-ynamide6(IIc) was similarly Under identical conditions cinnamide was re-completely cleaved by sodamide in liquid ammonia covered quantitatively. Our reaction bears some at -33O 4,4-dimethylpent-2-ynoicacid not being formal resemblance to the Haller-Bauefl sodamide formed. Additional activation of the triple bond thus cleavage of nonenolizable ketones. appears unnecessary for cleavage to occur. Repeti- Dimet hyl acet ylenedicarboxyla te (IIa) on iden tical tion of the reaction followed by carbonation treatment followed by addition of benzophenone afforded the above acid.’ Cymerman Craig and Moyle Proc. Chem. Soc. 1962 149. ’ Johnson and McEwen J. Amer. Chem. Soc. 1926,48,469. ’Vogel “Practical Organic Chemistry,” Longmans 1956 442.Haller and Bauer Compt. rend. 1908 147 824; Hamlin and Weston Org. Reactions 1937 9 1. Babayan J. Gen. Chem. U.S.S.R. 1940 10,480. I’ Fischer and Grob Helv. Chim. Acta 1956 39 417. -Mansfield and Whiting J. 1956 4761. Both phenylpropiolic and 4,4-dimethylpent-2-ynoic acid were recovered almost quantitatively after identical treatment demonstrating the resistance of the electron-repelling carboxylate ion to sodamide attack. However in the case of ap-acetylenic acids having a y-hydrogen atom the reaction took a different path resulting in a prototropic shift to give quantita- tively the corresponding allenic acids. Thus non-2-ynoic acid8 afforded nona-2,3-dienoic acid (b.p. 102-103”/0~5 mm.; ni5 1.4595 m.p.29”) and tetrolic acidg gave buta-2,3-dienoic acid1* (m.p. 64-66’). Completeness of the conversion was attested by the disappearance of the strong absorption maxi- * Wotiz J. Org. Chem. 1954 19 1580. * Henbest Jones and Walls J. 1950 3646. PROCEEDINGS mum at 2240 cm.-l (Ci C.) and its replacement by bands at 1960 or 1950 and 1970 cm.-l (-C:C:C.),re-spectively.ll Also with the former there was no light absorption above 215 mp,andin the latter no absorp- tion maximum at 3300 cm.-l (i C-H). The reaction thus offers a convenient alternative to existing prep- arations12 of straight-chain a/3y-allenic acids larger than buta-2,3-dienoic acid,10y12s13 often involving experimental difficulties elevated temperatures or low yields.This work was supported by a grant from the National Institutes of Health U.S. Public Health Service. (Received June 12th 1962.) lo Eglinton Jones Mansfield and Whiting J. 1954 3197. l1 Wotiz and Celmer J. Amer. Chem. SOC.,1952 74 1860. l2 Wotiz J. Amer. Chem. SOC.,1950 72 1639; Jones Whitham and Whiting J. 1957 4628. l3 Jones Whitham and Whiting J. 1954 3201. NEWS AND ANNOUNCEMENTS Chemical Society Symposia.-Symposia are being arranged in conjunction with the Anniversary Meet- ings of the Chemical Society to be held in Cardiff on March 26-29th 1963. The physical chemistry topic will be “Mechanisms of Ionic Polymerisation,” and the two organic chemistry subjects chosen are “Some Recent Developments in Alkaloid Chemistry” and “Some New Aspects of Terpene Chemistry.” The papers will not be published in full but abstracts will be available to those who register for the meeting.Full details of these Symposia and of the Anniversary Meetings will be available in January 1963 on application to the General Secretary of the Society Burlington House London W. 1. Election of New Fellows.-106 Candidates whose names were published in Proceedings for June have been elected to the Fellowship. Deaths.-We regret to announce the deaths of the following Dr. L. Richter (1.7.62) Chairman of Gideon Richter (G.B.) Ltd. and Mr. J. Robertson (20.6.62) Lecturer at the University of Glasgow. Medola Medal for 1962,-The Medola Medal is the gift of the Society of Maccabaeans and is normal- ly awarded annually.The next award will be made early in 1963 to the chemist who being a British subject and under 30 years of age at December 31st 1962 shows the most promise as indicated by his or her published chemical work brought to the notice of the Council of the Royal Institute of Chemistry before December 31st 1962. No restrictions are placed upon the kind of chemical work or the place in which it is conducted. The merits of the work may be brought to the notice of the Council either by persons who desire to recommend the candidate or by the candidate him-self by letter addressed to The President The Royal Institute of Chemistry 30 Russell Square W.C. 1 the envelope being marked “Medola Medal.” The letter should be accompanied by six copies of a short statement on the candidate’s career (date of birth education and experience degrees and other qualifications special awards etc.with dates) and of a list of titles with references of papers or other works published by the candidate independently or jointly. Candidates are also advised to forward one reprint of each published paper of which copies are available. The Beilby Medal and Prize 1963.-Awards from the Sir George Beilby Memorial Fund are made by the Administrators of the Fund representing the Royal Institute of Chemistry the Society of Chem- ical Industry and the Institute of Metals. Sir George Beilby had been President of each of these three bodies and they jointly sponsored the appeal for subscriptions whereby the Fund was raised as a memorial to him after his death in 1925.The Beilby Medal and Prize which consists of a gold medal and a substantial sum of money is specified as being “For Advancement in Science and Practice.” Such an award is offered at intervals of AUGUST 1962 two years but more than one may be made on the same occasion if there are several candidates of sufficiently outstanding merit. Thus two awards were made in 1961 each carrying a prize of 100 guineas. The awards are made to British investigators in science in recognition of independent original work of exceptional merit carried out continuously over a period of years and involving the development and application of scientific principles in any field related to the special interests of Sir George Beilby i.e.in chemical engineering fuel technology or metallurgy in their modern interpretations. The awards are in- tended as an encouragement to younger men and women (preferably under age 40) who have done distinguished work of practical significance in any of these fields. Consideration will be given in due course to the making of an award (or awards) from the Fund in 1963. Outstanding work of the nature indicated may be brought to the notice of the Administrators either by persons who desire to recommend the candidate or by the candidate himself not later than December 31st 1962 by letter addressed to The Convener of the Administrators Sir George Beilby Memorial Fund The Royal Institute of Chemistry 30 Russell Square London W.C.l.The letter should be accompanied by nine copies of a short statement on the candidate’s career (date of birth education and experience degrees and other qualifications special awards etc. with dates) and of a list of titles with references of papers or other works published by the candidate independent- ly or jointly. Photographic copies of these documents are acceptable. Candidates are also advised to for- ward one reprint of each published paper of which copies are available. British Committee on Chemical Education.-The Royal Society and the Royal Institute of Chemistry have recently established a British Committee on Chemical Education whose initial terms of reference are to promote improvement in the teaching of chem-istry in schools.The Committee comprises nominees from the Royal Society the Royal Institute of Chem-istry the Chemical Society the Society of Chemical Industry the Science Masters’ Association the Association of Women Science Teachers the Ministry of Education and the Scottish Education Department together with several persons who have been invited to serve in their personal capacity but with special reference to their experience in diverse fields of chemical education. The members of the Committee are Professor C. C. Addison Professor R. M. Barrer Mr. N. Booth Mr. M. G. Brown Mr. J. H. Clayton Mr. E. H. Coulson (Vice-president) Miss F. M. Eastwood Professor F. Fairbrother Mr. H. F. Halliwell Mr.H. R. Jones Mr. A. J. Mee Professor R. A. Morton Professor R. S. Nyholm and Dr. G. Van Praagh. The Secretary of the Committee will be Mr. D. G. Chisman. The main functions of the new Committee will be to co-ordinate and publicise the various develop- ments that are taking place in chemical education to initiate projects for modemising the teaching of chemistry in schools and generally to disseminate information on what is happening in various spheres of chemical education in this country and overseas. Personal.-The Senate of the University of Dur- ham is to confer the degree of Doctor of Science on the Rev. Dr. E. E. AynsZey for his researches in the field of Inorganic Chemistry. The title of Reader in Inorganic Chemistry has been conferred on Dr.I. R. Beattie in respect of his post at King’s College. The title of Professor Emeritus has been conferred upon Professor J. H. Birkinshaw Professor of Bio- chemistry at the London School of Hygiene and Tropical Medicine since 1956. Professor N. B. Chapman has been appointed the R.T. French Visiting Professor in the University of Rochester New York U.S.A. from September 1962 to June 1963. Mr. B. E. P. Clement has been appointed Chemist and Bacteriologist Chelmsford Corporation Water- works. Dr. J. F. Duncan has been appointed to the Chair of Inorganic and Theoretical Chemistry at the Victoria University Wellington New Zealand. Mr. W. K. Ellison has resigned his appointment as Senior Scientific Officer with the Trent River Board to take up an appointment as Chemist to the Lancashire River Board.Dr. N. Evers Dr. G. E. Foster and Dr. D. C. Garratt have been elected Honorary Members of the Pharmaceutical Society. Lord Fleck will give the opening address at the Conference on National Inspection to be organised by the Institution of Engineering Inspection at New College Oxford in September next. Dr. R. M. Gaze has been awarded an Alan Johnston Lawrence and Moseley Research Fellow- ship by the Council of the Royal Society at the Department of Physiology The University of Edinburgh from October 1st next. Dr. A. S. Haigh has been appointed Works Manager Designate of Macclesfield Works Imperial Chemical Industries Limited Pharmaceuticals Divi- sion.Sir Charles Harington will be succeeded as Director of the National Institute for Medical Research by Dr. P. B. Medawar C.B.E. D.Sc. F.R.S. as from August lst 1962. Mr. E. Le Q. Herbert who recently retired as Managing Director of the Shell Refining Co. Ltd. has been appointed a Director of Whessoe Ltd. Dr. R. E. Hester who was awarded a N.A.T.O. Fellowship for 1962/3 has taken up a post-doctoral research position in the Department of Inorganic Chemistry The University Cambridge. Dr. G. J. Hills has been appointed to the Chair of Physical Chemistry at the University of Southampton as from October 1st next. Dr. L. M. Jackman has been appointed to the Chair of Organic Chemistry at the University of Melbourne Victoria. Professor J.Michalski of the Technical University of Lodz has been elected a member of the Polish Academy of Science. Dr. J. A. Miller has been appointed to a Smithson Research Fellowship by the committee representing the Royal Society and the University of Cambridge at the Department of Geodesy and Geophysics Cambridge from October 1st next. Dr. G. W. A. Milne will take up the position of Visiting Fellow at the U.S. National Institutes of Health Bethesda Maryland U.S.A. as of September 1st next. Mr. G. W. A. Newton has been awarded the Research Diploma of the Royal Institute of Chem- istry for work carried out at the City College of Technology Liverpool. Dr. D. W. Ockenden has completed his fellowship at McMaster University Hamilton Ontario and has returned to his post in the Chemical Services Department U.K.A.E.A.Windscale. Mu. J. W. Parkes has tendered his resignation as Joint Managing Director of W. & H. M. Goulding Ltd. and its wholly-owned subsidiary companies and has accepted appointment as Vice-chairman of those companies as of July lst 1962. Dr. F. H. Peakin Local Director of I.C.I. (Export) PROCEEDINGS Ltd. Frankfurt has been appointed Manager of the newly formed I.C.I. subsidiary in Germany I.C.I. (Deu t schland) GmbH. Mr. W. C. Peck Chairman of Apex Construction Ltd. has been re-elected to the Senate of the University of London. Dr. J. T. Pinhey has been appointed to a Lecture- ship in Organic Chemistry in the University of New South Wales Australia.Mr. G. A. C. Pitt was elected President of the Society of Cosmetic Chemists of Great Britain at their Annual General Meeting. Mr. N. H. Pvutt has been appointed Vice-principal and Head of the Science Department of the re- organised Brighton Technical College as of September 1st next. Dr. A. 1. Scott has been appointed Associate Professor of Organic Chemistry at the University of British Columbia Vancouver. Dr. A. J. Swallow Imperial College London is spending some weeks as guest Professor at the Institute for Physical Chemistry and Colloid Chem- istry The University of Cologne. Lord Todd has been appointed a member of a committee set up by the Government to review the organisation for the promotion of civil science by Government agencies.Dr. R.G. Wilkins of the University Sheffield will be on leave of absence from October 1962 until June 1963 at the Max-Planck Institute. Sir Alan Wilson has resigned his position as a Director and Deputy Chairman of Courtaulds Limited. The William Julius Mickle Fellowship for 1961-62 has been awarded by the Senate of the University of London to Professor J. Yudkin of Queen Elizabeth College for his work on nutrition. FORTHCOMING SCIENTIFIC MEETINGS London Thursday October 11 th 1962 at 7.30 p.m. Pedler Lecture “Amino-acid Sequences in Certain Enzymes,” by Dr. F. Sanger F.R.S. To be given in the Lecture meatre me Royal Institution Albe-marle Street W.l. Thursday October 25th 1962 at 2 p.m. One-day Symposium on “me Chemistry of the Early Transition Elements.” To be held in the Main Lecture Theatre the Chemistry Department Uni- versity College.(A full programmeis beingcirculated.) Manchester Wednesday September 26th 1962 at 10 a.m. All-day Symposium “Chemistry and Mental Disease.” Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held at the University. Fellows Wishing to attend should communicate with Mr. H. H. Armstrong T.D. B.Sc. F.R.I.C. at the StockPod allege for Further Education Wellington Road South Stock- port Cheshire. AUGUST 1962 287 APPLICATIONS FOR FELLOWSHIP (Fellows wishing to lodge objections to the election of these candidates should comm.unicate 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.) Al-Jallo Hikmat Naiem Abbo B.Sc. Department of Organic Chemistry Imperial College Imperial Institute Road S.W.7. Anderson Noel George Ph.D. “Mayfield,” Mitchley Avenue Sanderstead Surrey. Andrews Clive William Dempster. 80 Barnsfield Crescent Totton Southampton. Aue Donald Henry. 2606 Brandon Road Columbus 21 Ohio U.S.A. Baird Margaret Bennett Ph.D. 47 Haydown Road Elizabeth Grove South Australia. Banks Geoffrey Robert B.A. Chemistry Department The University of Keele North Staffs. Barker James Albert B.Sc. 77 Beaconsfield Road, Ipswich Suffolk.Benson Herbert Linne Jr. Ph.D. 8311 Rockhill Street Houston 17 Texas U.S.A. Bermejo-Martinez Francisco Dr.sc. Faculty of Sciences Santiago de Compostela Spain. Chivers. Tristram. B.Sc. 1 Alma Terrace. Gilesgate. Durham City. ‘ I Coowr. Denvs Geoffrev Tvndale. B.Sc. Bevill’s Hill. B;idgerule,-Holsworth? Devon. ’ Davey Nell Barbara. 8 Farrant Street Prospect South Australia. Donnelly Jillian Kay B.Sc. Organic Chemistry Depart- ment University of Adelaide South Australia. Dowding Anthony John Frederick. 15 Warwick Avenue Quorn Loughborough Leics. Eilbeck William John B.Sc. Department of Chemistry, University College of North Wales Bangor Caerns. Forster Thomas Edward. 82 King Street Bedworth Nuneaton Warks.Freenor Francis Joseph A.B. Department of Chemistry, University of Washington Seattle 5 Wash. U.S.A. Gero Stephan DOV M.Sc. Department of Organic Chem- istry The University of N.S.W. Broadway Sydney Australia. Glogovsky Robert Louis B.S. Chemistry Department University of Colorado Boulder Col. U.S.A. Glover Alan Donald B.A. lo00 Morewood Avenue Pittsburgh 13 Pa. U.S.A. Gobbett Edwin M.A. D.Phi1. “Ravenswood,” 3A London Road Tonbridge Kent. Goodfellow Robin John. Magdalen College Oxford. Halstead John Outram B.Sc. 20 Corbett Street Roch- dale Lancs. Harrison Anthony Carruthers B.Sc. 297 Bramhall Lane South Bramhall Stockport Ches. Hart Charles Richard B.Sc. 7 Wyatt Road London N.5. Haug Patricia Ann. c/o Mrs. Hurwitz 504 W. 110 Street llB New York 25 N.Y.U.S.A. Hickmott Peter William B.Sc. 4 Pennine Close Blackley Manchester 9. Hubbard Edmund Francis. 203 Glenmore Street, Wellington New Zealand. Jones Kenneth Morgan B.Sc. 25 Ffrydlas Road Bethesda Nr. Bangor N. Wales. Joynt Vernon Peregrin M.Sc. N.C.R.L. C.S.I.R. P.O. Box 395 Pretoria South Africa. Kaplan Fred Ph.D. Department of Chemistry Univer- sity of Cincinnati Cincinnati Ohio U.S.A. Khorasani Syed Shah Mohammad Ashfaque M.Sc. Department of Chemistry Dacca University Dacca 2, East Pakistan. Little Nigel Derek B.Sc. 44 Weston Way Weston Favell Northampton. McCartin Peter James Ph.D. Department of Chemistry University of Minnesota Minneapolis 14 Minn. U.S.A. McCormack John Joseph Jr. B.S. Department of Pharmacology Yale University School of Medicine 333 Cedar Street New Haven Conn.U.S.A. Marlow William M.Sc. A.R.T.C. M.P.S. Department of Chemistry The School of Pharmacy 29/39 Bruns- wick Square London W.C.1. Marr. Eleanor Best. Ph.D. 315 East 69th Street New York 21 N.Y. U:S.A. OIiver. John Anthony A.R.I.C. 101 Bridgnorth Road Wollaston StourbGdge Worcs. Panuganti Venkata Krishna Rao M.Sc. The Patent Office (Govt. of India) 214 Lower Circular Road Calcutta 17 India. Pearce Anthony Arthur B.Sc. Sunnymead Epperstone Nottingham. Pearce Philip James B.Sc. 42 Strathmore Street, Bentleigh S.E.14 Melbourne Victoria Australia. Phillips Arnold Gilbert B.A. 18914 Stoepel Avenue Detroit 21 Michigan U.S.A. Placzek Daniel Walter B.S.Department of Chemistry, University of Washington Seattle 5 Wash. U.S.A. Raffa Lina Dr. Istituto di Chimica Farmaceutica e Tossicologica Via S. Eufemia 19 Modena Italy. Ranger Geoffrey Malcolm. 26 Deerswood Court Ifield Sussex. Reynolds Anthony Desmond B.Sc. 1 Sheepcote Gardens Denham Uxbridge Middx. Rubalcava Hector Emmanual Ph.D. Department of Chemistry University College Upper Merrion Street Dublin 2 Ireland. Sargent Frederick Peter B.Sc. School of Chemistry The University Leeds Yorks. Sarkis George Yonathan B.Sc. 39 Onslow Gardens s.w.7. Skinner George Anthony B.Sc. 22 York Street, Penzance Cornwall. Smith Robert Francis Ph.D. Bede College Durham City. Sommers Jay Richard B.S. Department of Chemistry Alumni Hall University of Pittsburgh Pittsburgh 13 Pa.U.S.A. Sroog Cyrus E. Ph.D. Film Research Laboratory E. I. Du Pont de Nemours & Co. Wilmington 98 Delaware U.S.A. Stewart Oliver John B.Sc. Killydart Newtownstewart Omagh Co. Tyrone N. Ireland. Swinton Findlay Lee Ph.D. Chemistry Department Royal College of Science and Technology George Street Glasgow C.1. Tiwari Hanuman Prasad M.Sc. Chemistry Department Whiffen Laboratory Imperial College Imperial Institute Road S.W.7. Valkanas George Ph.D. D.I.C. Technisch-chemisches Laboratorium E.T.H. Zurich Switzerland. Wall Donald Kenneth B.Sc. “Denholme,” Buxton Road High Lane Nr. Stockport Ches. Waterfield Charles Garrow. New College Oxford. Webb Jimmy Lynn B.S. Chemistry Department Florida State University Tallahassee Florida U.S.A.Weinshenker Ned Martin. 225 Sterling Place Brooklyn Wood John William Michael. 102 Oxhawth Crescent 38 N.Y. U.S.A. Bromley Kent. Wiedemann Otto Dr.rer.nat. Munchen-Geiselgasteig Wright John Magdalen oxford. Nordl. Munchener Str. 10a Germany. Williams Richard Murray B.Sc. No. 1 Windward Zaharia William Ph.D. Department of Biochemistry Birkenhead Road Meols Hoylake Ches. University of British Columbia Vancouver Canada. ADDITIONS TO THE LIBRARY The portraiture of the Honourable Robert Boyle, Fellow of the Royal Society. R. E. W. Maddison. (Re- printed from the Annals of Science.) Pp. 214. Taylor and Francis Ltd. London. 1962. (Presented by Dr. Maddison.) Progress in nuclear energy. Series IX. Analytical Chem- istry.Vol. 1. Edited proceedings of the Second Inter- national Conference on the Peaceful Uses of Atomic Energy Geneva 1958. Edited by M. T. Kelley. Pp. 372. Pergamon Press. London. 1959. Progress in nuclear energy. Series IX. Analytical Chem- istry. Vol. 2. Edited by C. E. Crouthamel. Pp. 400. Pergamon Press. Oxford. 1961. The radiochemistry of uranium. J. E. Grindler. Spon- sored by the U.S. Atomic Energy Commission. (Nuclear Science Series NAS-NS 3050.) Pp. 350. Subcommittee on Radiochemistry. Washington. 1962. (Presented by the publisher.) Methods for emission spectrochemical analysis spon- sored by ASTM Committee E-2 on Emission Spectro- scopy. 3rd edn. Pp. 685. ASTM. Philadelphia. 1960. Absorption spectroscopy. R. P. Bauman.Pp. 61 1. John Wiley & Son. New York. 1962. Introduction to molecular spectroscopy. G. M. Barrow. Pp. 318. McGraw-Hill. New York. 1962. Standard X-ray diffraction powder patterns. H. E. Swanson et al. U.S. National Bureau of Standards Monograph 25 (1). Pp. 56. U.S. Govt. Printing Office. Washington. 1962. Die Struktur Wassriger Elektrolytlosungen und die Hydratation von Ionen. 0. J. Samoilow. Pp. 147. B. G. Teubner. Leipzig. 1961. The influence of impurities on viscosity and density in water solutions of phosphoric acid. S.-E. Dahlgren. (Acta Polytechnica Scandinavica Chemistry including Metallurgy Series No. 19.) Pp. 21. Royal Swedish Academy of Engineering Sciences. Stockholm. 1962. (Presented by the publisher.) Organophosphorus monomers and polymers.Ye. L. Gefter. Translated from the Russian by J. Burdon. Pp. 302. Pergamon Press. Oxford. 1962. (Presented by the publisher.) Standard methods of chemical analysis. Edited by N. Howell Furman. Vol. 1. 6th edn. Pp. 1401. van Nostrand. New Jersey. 1962.(Presented by the publisher.) Heavy electrodeposition of nickel. J. W. Oswald. Pp. 40. International Nickel Co. (Mond) Ltd. London. 1962. (Presented by the publisher.) Water treatment for public and industrial supplies. A. H. Waddington and W. J. M. Cook. (Reprinted from Chemical Engineering Practice.) Paterson Engineering Co. Ltd. London. 1962. (Presented by the publisher.) Progress in Medicinal Chemistry. Edited by G. P. Ellis and G. B. West. Vol. 2. Pp. 201. Butterworths.London. 1962. Reprints for the Conference Sessions of the Second World Congress of Man-made Fibres held in London 1962. Sponsored by the Comite International de la Rayonne et des Fibres Synthktiques. Comit6 Inter- national de la Rayonne et des Fibres Synthktiques. London. 1962.(Presented by the publisher.)