摘要:

AbstractFluorine diluted with nitrogen reacted with hydrofluorocarbons such as benzotrifluoride, in solution in fluorocarbons or in pentachloroethane, to give high‐boiling products, presumably from condensation reactions proceeding simultaneously with fluorination. Treatment of these products in the liquid phase first with fluorine under more drastic conditions, and then with silver difluoride, gave a series of perfluoro‐lubricants and res

ISSN:0021-8871    

DOI:10.1002/jctb.5010020301

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractIn the new anodic method, the specimen carrying the oxide film to be transferred is cemented to glass, and the whole of the metal is dissolved away by anodic action, leaving the film attached to the glass. The method has the advantage that large areas of films are transferred to a rigid, transparent support, without any doubt as to which of the two surfaces represents the outer surface of the film as present on the metal. The area of the pieces transferred can be measured, and the metal (or metals) in the films estimated by microanalysis; alternatively by transferring to glass coated with petroleum jelly, the wrinkling or curling of the film gives information about the stresses present in the films when they are clinging to the metal. The validity of the method is shown by the fact that the transparency and appearance of the film depend on the temperature and time of the heating of the metal but are independent of the electrical conditions in the cell.

ISSN:0021-8871    

DOI:10.1002/jctb.5010020302

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe search for technically applicable methods for the synthesis and preparation of naturally occurring organic phosphates includes finding new ways of phosphorylation and the application of up‐to‐date physico‐chemical methods for purification and analysis. The achievements of Todd and his collaborators in synthesizing pyrimidine and purine nucleotides, including adenosine triphosphate, have contributed greatly to the advances in this field, in which so many others have taken part, including my colleagues and myself.The purpose of this paper is to present the background of this synthetic adventure—a kind of stocktaking and a story largely dependent on published and printed matter, scattered in many journals and treated in articles and books [e.g. Baldwin, 1947; Lipmann, 1941; Lipmann&Kaplan, 1949; Umbreit, 1947 (added at the proof‐reading stage: Avison&Hawkins, 1951; Lynen&Koenigsberger, 1950, 1951; Oesper, 1950; Hill&Morales, 1950, 1951)], and as such far from

ISSN:0021-8871    

DOI:10.1002/jctb.5010020303

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractData from the rectification of ethanol–water mixtures in a wetted‐wall column have been analysed using measured values for the diffusion coefficient of ethanol in the liquid phase. The data from differential measurements of the concentration distribution cannot be correlated satisfactorily but the liquid‐film resistance appears to depend on a function of the Hatta groupconfirming the conclusions of Chari&Storrow for data on methanol–water m

ISSN:0021-8871    

DOI:10.1002/jctb.5010020304

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe fluorination of hydrocarbons in the vapour phase by the use of cobalt trifluoride is readily achieved, and, when controlled conditions of reaction are employed, good yields of fluorocarbon products are obtained. An apparatus for carrying out this type of reaction, and also a convenient cell for the generation of fluorine are described. The syntheses of some of the hydrocarbon starting‐materials are give

ISSN:0021-8871    

DOI:10.1002/jctb.5010020305

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe melt‐viscosity and density of a series of phenol–formaldehyde novolak resins of molecular weights varying between 400 and 900 have been studied in the temperature range 100–250°. Similar studies have been carried out for phenol (50–100°) and 2 : 2′‐dihydroxydiphenylmethane (125–190°).The melt‐viscosity results have been examined in the light of Eyring's theory of viscosity and it is seen that the energy of activation for viscous flow falls rapidly as temperature increases and tends to steady values at high temperatures. These steady values are almost linearly related to molecular weight.The rapid fall in energy of activation as temperature increases is attributed to the breakdown of association forces, mainly hydrogen bonds. At high temperatures flow is believed to take place by the movement of single molecules, but at low temperatures the large energies of activation suggest that flow takes place by associated dimers, trimers etc. breaking away from the general association field that surrounds them.The coefficient of cubical expansion α is found to decrease rapidly from phenol to a resin of molecular weight about 400 and then more slowly as molecular weight increases; α also increases sligh

ISSN:0021-8871    

DOI:10.1002/jctb.5010020306

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractSodium benzoate has been shown to be an effective inhibitor of the corrosion of mild steel in distilled water, a moderately hard mains‐water and very dilute (e.g. 0·03%) sodium chloride solutions. The concentration of benzoate required for inhibition is greater (0·5%) for machined than for emeried surfaces (0·1% in favourable conditions) and for mains water or chloride solutions (1·0 or 1·5%) as compared with distilled water (0·5%).Movement of the solution, or saturation with oxygen, assists inhibition, but a pH below 6 causes breakdown. Comparisons with sodium chromate show that sodium benzoate is less efficient; it is, however, a ‘safe’ inhibitor since it does not lead to intense localized corrosion when the concentration is just below the minimum for protection. The following benzoates have also been shown to possess inhibitive properties: potassium, lithium, zinc and magnesium. Zinc is partly, and copper and aluminium completely, protected in 0·05% sodium benzoate solution at room temperature.An unusually high rate of hydrogen gas evolution occurs in dilute sodium chloride solutions containing insufficient sodium benzoate for complete inhibition. A tentative explanation is suggested. The detailed mechanism of the protective action of sodium benzoate is not yet established, but electrode‐potential measurements and film‐stripping experiments provide evidence for the view that anodio inhibition produces and maintains a continuous film. Electron‐diffraction examination of the stripped film has so far yielded definite evidence of γ‐ferric

ISSN:0021-8871    

DOI:10.1002/jctb.5010020307

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA method for the determination of gas solubility is described which is particularly suitable for use with viscous liquids. The liquid, freed from other gases, is saturated with the gas under examination at a known pressure. A known volume of the saturated liquid is then streamed into an evacuated vessel and the liberated gas extracted by a Töpler pump and measured. Figures illustrating the accuracy obtainable are given for lubricating oils with a range of viscosity, and the necessary modifications for normal liquids are indicated

ISSN:0021-8871    

DOI:10.1002/jctb.5010020308

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY