ISSN:0021-8871    

DOI:10.1002/jctb.5010050107

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractEarlier work had suggested that surface‐active agents played a more specific role in corrosion processes than was generally supposed. A series of sodium alkyl sulphates were prepared, and the behaviour of tin specimens immersed in their dilute aqueous solutions was examined. Some weight‐loss experiments were made, and the effects of constitution and concentration upon corrosion rate determined.The corrosion was not general, but essentially a point attack, so that a note of the distribution of corrosion, as well as of its extent, was made. Theory suggests that the readiness with which a solution corrodes tin lies in its ability to dissolve the existing protective oxide layer on the metal surface. However, experiments showed that stannic oxide was insoluble in neutral solutions of any of the materials used.Further experiments involving breakdown‐potential measurements and pressure tests on stripped oxide films revealed that the surface‐active solute ruptures, rather than dissolves, the oxide film. This film is generally sufficiently stressed for many potential cracks to exist. Adsorption of a surface‐active solute on the surfaces of these cracks so reduces their adhesion that they develop into actual failures, and ultimately into corrosion sites. The subsequent activity of these sites is controlled in part by the structure of the adsorbed layer of solute at the meta

ISSN:0021-8871    

DOI:10.1002/jctb.5010050102

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractA pilot‐scale Thylox plant has been fabricated, and operated first on synthetic mixtures of town's gas and hydrogen sulphide at Dominion Laboratory, Wellington, New Zealand, and subsequently on crude gas at the Wellington Gas Company's works.It has been found that hydrogen cyanide present in coal gas has a serious effect on the removal of hydrogen sulphide by the Thylox process, but satisfactory operation is obtained when the cyanide content of the gas entering the Thylox process has been reduced to below 10 grains/100 cu. ft.Operated in conjunction with the prior removal of hydrogen cyanide, the Thylox process has proved capable of reducing the hydrogen sulphide content of gas to below 1 grain/100 cu. ft. Of the sulphur in the gas 85% is recovered as sulphur of significant commercial valu

ISSN:0021-8871    

DOI:10.1002/jctb.5010050103

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractPrevious and submitted evidence on the mechanism of interaction between an alcohol and a hydrogen halide points to the conclusion that the formation of an alkyl halide entails two steps: the rapid formation of an oxonium halide, ROH2+X−, and the rate‐determining dehydration of it. Results from the studies of kinetics and optical rotatory power are as yet inconclusive on the mechanism of the second step, but they point to the concurrence of several modes.The maximum amount of hydrogen halide absorbed by an alcohol depends on the nature of the alcohol and on the temperature. This amount is of great significance because it determines the maximum concentration of the oxonium halide, and also can control the extent to which the water produced reduces the rate of formation of alkyl halide. Because of these points, and because the concentration of halide ion can be increased, certain added substances, such as pyridine, dioxan and even water, can increase the rate of formation and final yield of alkyl halide.Results of experiments on the solubility of hydrogen chloride in different alcohols, and on the extraction of the halide by water, are discus

ISSN:0021-8871    

DOI:10.1002/jctb.5010050104

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe osmotic pressures of dilute solutions of 12.2%‐nitrogen‐content cellulose nitrate have been determined, with homologous series of methyl ketones and alkyl acetates as solvents. Values of the interaction constant μ have been estimated from the slopes of plots of reduced osmotic pressure against concentration. The order of solvent power obtained from values of μ is compared with the orders given by suggested estimates of solvent power from parallel precipitation and viscosity studies. The volumes of hexane required for initial phase‐separation from solution appear to be at least semi‐quantitative measures of solvent power as estimated from values of μ. Limiting viscosity numbers and the initial slopes of plots of ηsp./cagainstccan, to a less extent, be related to solvent power, but the relative stiffness of the chains seems responsible for the absence of any obvious relationship between solvent power and either the Hugginsk' value or the Spurlin slope of Martin plot divided by limiting visco

ISSN:0021-8871    

DOI:10.1002/jctb.5010050105

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractChromium hexacarbonyl raises the spontaneous ignition temperature (S.I.T.) of various hydrocarbon fuels, and therefore would be expected to have anti‐knock properties. However, determination of the highest useful compression ratio (H.U.C.R.) shows that the carbonyl is a pro‐knock agent; with a ‘pool’ petrol, the maximum pro‐knock effect (decrease of 5 in octane number) is approached at an unusually low concentration of additive (0.02 g./l.). Similarly, a very small concentration raises the cetane number of a Diesel fuel by about 3; the effect is not increased by raising the concentration. The carbonyl lowers the S.I.T. of benzene, and raises the H.U.C.R. from 14.5 to 15.6. The latter effect is attributed to inhibition of pre‐ignition. Explanations of this anomalous behaviour of chromium hexacarbonyl are advanced, based on either of the two current theories of knock. With fuels containing 1 g./l. of the carbonyl, chromium sesquioxide (Cr2O3) is deposited in the combustion chamber; this can be reduced but not eliminated by a small proportion of ethylene dichloride or dibromide

ISSN:0021-8871    

DOI:10.1002/jctb.5010050106

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY