ISSN:0021-8871    

DOI:10.1002/jctb.5010050812

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractFluorination of benzene, in the vapour phase, over manganic fluoride at temperatures between 200°and 350°gave a complex mixture of polyfluorocyclohexenes and dimeric material; monofluorobenzene and unreacted benzene were also present in the products of fluorination at 200°to 300°. Partial resolution of the mixture was achieved to give octa‐ and hepta‐fluorocyclohexenes. These olefins gave dibromo‐addition compounds and were oxidised readily to fluorodibasic acids. Dehydrofluorination of a heptafluorocyclohexene and oxidation of the resultant diolefin afforded difluoromalonic and tetrafluorosuccinic acids. Oxidation of the dimeric material gave tetrafluorosucc

ISSN:0021-8871    

DOI:10.1002/jctb.5010050801

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

Abstract4‐Amino‐5‐methylaminopyrimidine has been synthesized by reduction with lithium aluminium hydride of the formyl group in 4‐amino‐5‐formamido‐2‐methylthiopyrimidine followed by removal of the 2‐substituent. A route to 5‐amino‐4‐hydroxy‐6‐methylaminopyrimidine is described. The Whitehead synthesis has been extended to the use of cyanoacetic acid as a reactant. Decarboxylation of the resulting 4‐amino‐5‐carboxy‐3‐methyl‐2‐pyrimidone, however, gave unexpectedly 2‐hydroxy‐4‐methylaminopyrimidine. Several improvements in the preparation of known related (methylated) compounds, including the first isolation of 5‐amino

ISSN:0021-8871    

DOI:10.1002/jctb.5010050802

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe determination of low concentrations of hydrogen sulphide in gas has been investigated. A modified calibration technique has been developed for the methylene blue method and its accuracy verified volumetrically and gravimetrically. Employing the methylene blue method as a primary standard, the relation between optical density and sulphur content of lead sulphide stains, obtained by passing gas through absorbent paper, has been replotted, using a specially designed photoelectric densitometer.

ISSN:0021-8871    

DOI:10.1002/jctb.5010050803

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractFifteen specimens of sodium alginate from various brown algae, including species ofLaminaria, FucusandAscophyllum, have been prepared in the laboratory or obtained from commercial sources. Tests on these samples included measurements of optical rotation, ionic mobility, rate of sedimentation, viscosity and content of sulphated ash. Most specimens were homogeneous by electrophoresis and in the ultracentrifuge. The content of alginate of the samples varied from 61.7 to 99.6%. Rate of sedimentation was strongly dependent on concentration. Electrophoretic mobilities varied only slightly. Viscosity varied much more widely than other physical properties and was the best criterion of state of polymerization. Fucoidin was detected as impurity in some preparations.From the best preparations examined the following values were obtained: [α]d20° = −133°to −140°; μ = 2.9 to 3.1 × 10−4cm.2sec.−1volt−1at 25°, pH 5.5,I0.05;s40= 1.3 to 1.6 S (c= 0.5%); sulphated ash = 34.0 to 35.9%. Viscosity varied from 2 to 20 centistokes at 25°in 0°1n‐NaCl (c= 0.25% w/w). Values for [η] varied from 3.6 to 19.2 corresponding to a degree of polymerization of 210 to 1,100 and particle weight of 42,000 to 222,000. The specific refractive increment of sodium alginate was found

ISSN:0021-8871    

DOI:10.1002/jctb.5010050804

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe effect of a number of benzylidene and furfurylidene nitriles on the polymerization of styrene is investigated. Whereas the former class copolymerize readily, the latter are powerful inhibitors of polymerization. In the case of benzylidenemalonitrile, the effect of the penultimate monomer unit on further copolymerization is very marked.

ISSN:0021-8871    

DOI:10.1002/jctb.5010050805

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractA flow apparatus for the determination of equilibrium constants in the BaSO4/BaS/H2/H2O system has been described. Equilibrium constants in the temperature range 800°to 1100°are satisfactorily correlated by the equation log10KP= 5.447 + 697.5/Twith a maximum uncertainty of ±5% inKPat 80

ISSN:0021-8871    

DOI:10.1002/jctb.5010050806

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe performance of perforated and porous plates in achieving contact between gas and liquid in an absorption process is described. A mixture of carbon dioxide and air is passed upwards through a porous disk forming the base of a column containing liquid absorbent and is disseminated throughout the liquid as a mass of bubbles. 30% v/v monoethanolamine is used as absorbent in quantitative tests and the behaviour of other liquids is studied qualitatively. A distinction is made between two types of absorption taking place in the column. Absorption at the plate surface is extremely active and is essentially complete within a very small compass. Absorption throughout the remainder of the column is much less efficient per unit space and more akin to that of ordinary absorption towers. The influence of various factors (total gas flow rate, and the number, cross‐sectional area, and position of perforations) on ‘plate surface’ absorption is expressed quantitatively. The absorptive behaviour of commercial porous plates broadly follows that of perforated plates but, owing to a less standardised distribution of pores, is not so well defined. The effect on absorption efficiency of change in the flow pattern of the foaming liquor is t

ISSN:0021-8871    

DOI:10.1002/jctb.5010050807

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe rates of corrosion of tin specimens either intermittently or continuously immersed in several alkaline solutions have been compared. Similar solutions have been used to wash specimens of tinned steel that were exposed to the weather between washes in imitation of the service life of some tinned steel containers.The relative corrosive action of various solutions on intermittently immersed tin depends on the experimental conditions and may differ from that observed when the metal is immersed continuously. The results obtained with short periods of immersion are strongly influenced by the variation with the nature of the solution, the temperature and the condition of the metal surface, and of a period of delay between immersion of the metal and the onset of corrosion. A high rate of corrosion during the period between removal of the metal from the test solution and rinsing also introduces a potential cause of variation in the results of intermittent‐immersion tests.The deterioration in the protective quality of a tin coating on steel periodically washed in an alkaline solution can be predicted only moderately well from measurements of the corrosion rate of tin immersed in the solution. This deterioration results more from the enlargement of new pores formed in the coating during periods of exposure to the weather than from general dissolution of the tin, and silicates appear to restrain this action.In the conditions of the tests employed, with solutions of equivalent caustic alkalinity, sodium hydroxide, carbonate and phosphate had similar effects; sodium silicate (2 : 1) produced less deterioration; sodium metasilicate much less and sodium silicate (1 : 2), almost none. Additions of sodium sulphite to the washing solution had a negligible effect but additions of sodium chromate preserved both tin and steel. Additions of sodium hypochlorite either to washing or rinsing solutions accelerated deterioration of the coating except when made to solutions of sodium metasilicate or of sodium silicate (1 : 2

ISSN:0021-8871    

DOI:10.1002/jctb.5010050808

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractSeries of fractions (smaller than 0.5, 0–5–1, 1–2.5, 2.5–5, 5–10, 10–20μ in equivalent Stokes' diameter [E.S.D.]) prepared from three different samples of kaolin (A, B and C) have been examined with the aid of the following measurements: specific surface area,SA, by nitrogen sorption, bulk density, ρB, in vacuo, apparent density in carbon tetrachloride, percentage,f, airborne after five seconds, fractions in sieve analysis. The results extend and confirm those obtained earlier1with a similar series of fractions from another kaolin (D). Thus, the value ofSAagain agrees reasonably well with the specific surface areaSDcalculated from the E.S.D. for the finer fractions, but the ratio ofSAtoSDincreases progressively with increasing particle size (particularly sharply from the 1–2.5‐μ fraction onwards) until for the coarsest fractionSAis several‐fold greater thanSD. The bulk density has a minimal value for the 1–2.5‐μ fraction with samples A, B and D and for the 0.5–1‐μ fraction with sample C; the curves for percentage of airborne material after 5 seconds and for percentage,s, passing through an 80‐mesh sieve, both plotted against particle size, also show high values for the fine and the coarse fractions, with low values (often showing a clear minimum at a particular particle size) for the intermediate fractions. The detailed data for the sieve analysis are in broad agreement with the data for ρB,fands.The results of this study confirm the presence of ‘booking’ in the coarser fractions and of loo

ISSN:0021-8871    

DOI:10.1002/jctb.5010050809

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY