摘要:

α-Cyano-β-phenylglyceric acid has been prepared by the action of aqueous sodium hypochlorite on α-cyano-β-phenylacrylic acid. It is somewhat unstable and decomposes slowly on standing.When heated alone, it yields phenylacetic acid. Mild hydrolysis with mineral acid also gives phenylacetic acid. Hydrolysis under special conditions gives phenylpyruvic acid. The mechanism of these changes is discussed.

ISSN:1923-4287    

DOI:10.1139/cjr46b-016

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

It is shown that the above transition can be repressed (metastably) by using in place of pure ammonium nitrate a solid solution of potassium nitrate in ammonium nitrate. With such a solid solution containing 8 to 10% potassium nitrate, the temperature of the transition III → IV is depressed to about −20 °C. Such solid solutions can be prepared either by fusing the components together or by crystallizing from a mixed aqueous solution.

ISSN:1923-4287    

DOI:10.1139/cjr46b-017

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

An examination of the influence of the structure of charcoal adsorbents on the form of the water adsorption isotherm has been attempted by determinations of (1) surface areas of a series of charcoals of varying degrees of activation using nitrogen and butane as adsorbates; (2) total pore volume of each adsorbent sample by density measurements in helium and in mercury; (3) density of adsorbents when immersed in water; (4) adsorption isotherms for water vapour; and (5) surface areas of charcoals partly saturated with water vapour.The evidence appears to suggest that certain very small and certain very large voids in charcoal are not occupied by water vapour at any value of the relative pressure. The former, 10% by volume, are important in terms of surface area; the latter, 30% by volume, influence pore volume calculations. An explanation of the shape of the water adsorption isotherm is attempted in the light of these facts. Estimates of the submicro, micro, and macro pore sizes show fair agreement when these are based upon either the capillary condensation theory or measurements of the total area and volume of the charcoal pores.

ISSN:1923-4287    

DOI:10.1139/cjr46b-018

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The apparent density of eight charcoal samples has been determined in a series of liquids at two temperatures, 25° and 55 °C. From the data a correlation between apparent density of the charcoal and surface tension of the measuring fluid is suggested. An attempt is made to explain this approximate regularity in terms of the surface free energy change on immersion.

ISSN:1923-4287    

DOI:10.1139/cjr46b-019

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The apparent density of water adsorbed on four different charcoals at 20 °C. has been measured by a method of helium displacement. At low relative pressures the density is appreciably higher than that of liquid water, but falls rapidly to nearly the normal density as the amount adsorbed increases. A very sharp drop in density occurs close to saturation, and is attributed to the blocking of the very small porous spaces through the advent of capillary condensation in this region. It is suggested that the apparent high initial density is due to the size of the molecules of the measuring fluid rather than to the compression of the adsorbed film.The apparent density of the adsorbed water on the desorption branch of the isotherm differs from that on the adsorption branch, which suggests that the mechanisms of adsorption and desorption differ. An attempt has been made to evaluate the constantsVmandCof the multimolecular adsorption theory from one of the adsorption isotherms.

ISSN:1923-4287    

DOI:10.1139/cjr46b-020

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A full account of the experimental procedures used to determine the number average molecular weights of a series of polyvinyl acetates is given. Adsorption of polyvinyl acetate on a cellophane membrane is demonstrated. The importance of this phenomenon is increased when cells of large ratio of membrane surface to cell volume are used. The presence of small amounts of sodium hydroxide in the membrane eliminates detectable adsorption and alters the osmotic pressure values. This change does not appear to be due to imperfect semipermeability of the membranes, and no adequate explanation of the phenomenon has been as yet discovered.

ISSN:1923-4287    

DOI:10.1139/cjr46b-021

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A study has been made of the flow of permanent gases (helium, hydrogen, nitrogen) and condensable vapours (diethyl ether and ethyl bromide) through a sintered glass plug. The permanent gases are transferred by a combination of Knudsen and Poiseuille flow, while the flow of condensable vapours diverges from these equations in such a fashion as to suggest surface transfer.The flow rates of the condensable vapours begin to fall off at about 50% of the saturation pressures. Hysteresis effects are also observed in this region. It is suggested that these phenomena are caused by the condensation of small amounts of vapour in critical regions of the glass structure.

ISSN:1923-4287    

DOI:10.1139/cjr46b-022

出版商:NRC Research Press    

年代:1946

数据来源: NRC