摘要:

The change in the viscosity property of solutions of high polymers on ageing has been investigated. It has been found that the variations in viscosity are due to changes in the molecular weight of the dissolved polymer, caused by the presence of small amounts of impurities. In particular, oxygen appears to give rise to degradation reactions, while iron salts cause the formation of gel structures. Solutions of the dry polymers in pure solvents, when aged in the absence of air, show only very small variations in viscosity. The investigation has been conducted with three polymers, polyvinyl acetate, polystyrene, and polymethyl methacrylate in solution in three solvents, bis(2-chloroethyl) ether, nitrobenzene, and bis(2-chloroethyl) sulphide.The principal reaction seems to occur between the impurity and the polymer, with the solvent acting as an inert medium. However, it appears that in the case of bis(2-chloroethyl) sulphide, reaction of iron salts with the solvent is possible.The intrinsic viscosity of polyvinyl acetate recovered from the aged solutions has been determined. Thek′ factor of Huggins has been evaluated from these measurements, and appears to change during some of the ageing processes.

ISSN:1923-4287    

DOI:10.1139/cjr46b-023

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The number average molecular weights of two series of polymer samples, recovered from aged solutions of polyvinyl acetate in bis(2-chloroethyl) ether, have been measured using a dynamic type osmometer. It is shown that these number average molecular weights change from sample to sample in a manner similar to the intrinsic viscosities of the recovered polymers. This confirms previous results, which suggested that the change in viscosity of solutions of high polymers on ageing was due primarily to changes in the molecular weight of the dissolved polymer. A method of evaluating a relative non-uniformity coefficient for the polymers is suggested.

ISSN:1923-4287    

DOI:10.1139/cjr46b-024

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Picryl chloride can be prepared from pyridine picrate and either phosphorus oxychloride or phosgene in 97 to 100% yield. The pyridine used in this process is recoverable as its picrate and thus acts as a non-expended carrier during repeated preparations. Two of the chlorine atoms react in phosphorus oxychloride while only one in phosgene furnishes picryl chloride. The latter acid chloride is, however, more economical in use owing to its lower cost and molecular weight.

ISSN:1923-4287    

DOI:10.1139/cjr46b-025

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The method of Kym for conversion of phenols into aromatic amines has been applied to picric acid. An 88% yield of picramide has been obtained by adjusting the reaction temperature to 173 °C., the molar urea: picric acid ratio to 3:1, and the reaction time to 36 hr.

ISSN:1923-4287    

DOI:10.1139/cjr46b-026

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

New instances of nuclear chlorination of benzene derivatives by the action of cold aqueous sodium hypochlorite are reported. The reaction gives good yields of monochloro derivatives when the orientation is favourable.

ISSN:1923-4287    

DOI:10.1139/cjr46b-027

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The fatty oil of hare's-ear mustard seed (Conringia orientalisL.) was examined. Constants of the oil were determined and a partial separation of the fatty acids was carried out by the methyl ester fractionation method. Palmitic, oleic, linoleic, eicosenoic, erucic, and lignoceric acids were identified. Erucic acid was found to be present in largest amount. The oil resembles rapeseed and other Cruciferae seed oils in this respect. The content of eicosenoic acid is estimated to be not more than 12% of the total fatty acids.

ISSN:1923-4287    

DOI:10.1139/cjr46b-028

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A method has been developed for the vapour phase oxidation of ethyl lactate to ethyl pyruvate (yield, 68%), using air as oxidant and a platinum catalyst prepared by electrolytic deposition.

ISSN:1923-4287    

DOI:10.1139/cjr46b-029

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A compound having the structure previously suggested for calycanine has been synthesized. It is a lepidyl-carboline but is not identical with the degradation product from calycanthine. As an alternative structure for calycanine its formulation as a carboline is abandoned and it is suggested that it is a compound formed by fusion of a carbazole and a pyridine nucleus.

ISSN:1923-4287    

DOI:10.1139/cjr46b-030

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The parachors of certain azoxy and related azo compounds have been found. Values for the N2O group have been calculated from the constants of Sugden and from the recalculated values of Mumford and Phillips. In most cases the experimentally determined values agree better with the values calculated from Sugden's data. Possible explanations for anomalous parachors are discussed.

ISSN:1923-4287    

DOI:10.1139/cjr46b-031

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Fractional dissolution has been applied to nitrated corn starch with the consequent removal of ethanol-soluble fractions. Hot and cold ethanol-soluble fractions have been removed in this way amounting to from 10 to 25% of the crude nitrate. The ethanol-soluble fractions, consisting of low-molecular weight and low nitrogen-content material, are not stabilized by ethanol. The insoluble portion is greatly stabilized as a result of the ethanol treatment.The insoluble residue left after ethanol treatment of crude starch nitrate possesses good explosive properties, a high nitrogen content, and high stability. The stabilization of starch nitrate by ethanol is shown to be the result of a dual action, namely, (a) removal of highly unstable material of low molecular weight and nitrogen content, and (b) the conferring of increased stability by some, as yet unknown, mechanism on the insoluble portion.

ISSN:1923-4287    

DOI:10.1139/cjr46b-032

出版商:NRC Research Press    

年代:1946

数据来源: NRC