摘要:

The temperature range of the measurement of vapor-pressure depression using a sensitive differential mercury micromanometer has been extended, and the behavior of a series of polyethylene samples having a molecular-weight range of 2500 to 24,000 was examined in toluene solutions at 75 °C. Good agreement was obtained between vapor-pressure lowering and other means of determining number-average molecular weights of several special compounds.

ISSN:0008-4042    

DOI:10.1139/v58-105

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The reactor neutron-capture cross section of 18-minute Rb88has been determined by an activation method. The yield of Rb89formed by successive neutron capture in Rb87was determined by counting the beta rays emitted by its daughter, 51-day Sr89. In these experiments Sr89is also produced by the Sr88(n, γ)Sr89reaction from the Sr88contamination in the rubidium target and from Sr88formed by the beta decay of Rb88. Corrections for the contributions from these sources to the yield of Sr89have been measured experimentally. The reactor neutron-capture cross section of Sr88has been measured to be 5.8 mb. for the conditions of the experiment. Taking 0.12 ± 0.3 barn for the thermal cross section of Rb87, the cross section of Rb88was found to be 1.0 ± 0.3 barn for reactor neutrons.

ISSN:0008-4042    

DOI:10.1139/v58-106

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The fusion of mixtures of alkylamine nitrates, RR'NH.HNO3(R' = H when R = methyl, isopropyl, isobutyl,n-amyl, and phenyl, and R' = C2H5when R = ethyl), and dicyandiamide, or calcium cyanamide, or calcium cyanamide and urea, yielded alkylguanidine nitrates. The latter were also obtained by heating solutions of alkylamine nitrates and calcium cyanamide. By treatment of the alkylguanidine nitrates with sulphuric acid, alkylnitroguanidines were prepared in good yields. A study of the effect of temperature on the yield ofn-amyl and of time and temperature on the yields of methyl, isopropyl, and isobutyl nitroguanidine was made. The solubility of methyl, isopropyl, isobutyl, andn-amyl nitroguanidine in water and 10% and 20% sulphuric acid solutions at 0 °C. was determined.

ISSN:0008-4042    

DOI:10.1139/v58-107

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Measurements of the equivalent conductance of sulphuric, nitric, and hydrofluoric acids were made in water – hydrogen peroxide mixtures by means of a direct-current method. It was found that in solvents containing a high percentage of hydrogen peroxide the conductivities of these acids were extremely low, and it is proposed that this results from a marked decrease in their degrees of dissociation. This proposal is supported by similar measurements made on the system water – strong acid – weak acid.

ISSN:0008-4042    

DOI:10.1139/v58-108

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

7-Chloro-2,3-dihydrobenzo(f)-l,4-dithiepin (IV) has been synthesized from 2-(2-chloro-ethylmercapto)-5-chlorobenzyl chloride (I). Attempts to synthesize the higher homologues of IV by this method failed because the required intermediates cleaved at the alkyl–sulphur bond. A reaction product ofp-chlorothiophenol, formaldehyde, and hydrogen chloride has been identified as 2,8-dichloro-6H,12H-dibenzo(b,f)-l,5-dithiocin (VI), a tricyclic system with the eight-membered ring containing two sulphur atoms.

ISSN:0008-4042    

DOI:10.1139/v58-109

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

A water-soluble polysaccharide isolated from white spruce wood containedD-galactose,L-arabinose, andD-xylose in a molar ratio of 21:3:1. Hydrolysis of the fully methylated polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (12 moles); 2,3,4,6-tetra-O-methyl-D-galactose (29 moles); 2,3,4-tri-O-methyl-D-galactose (34 moles); 2,6-di-O-methyl-D-galactose (0.5 moles); 2,4-di-O-methyl-D-galactose (45 moles); 2,3-di-O-methyl-D-xylose (5 moles); and monomethyl xylose (1 mole). When oxidized by periodate the polysaccharide consumed 1.18 moles of oxidant, and yielded 0.56 moles of formic acid per mole of anhydro-D-galactose. TheD-xylose was attributed to the presence of a xylan mixed with the arabogalactan in the original polysaccharide preparation. The methylation and periodate oxidation data showed that the arabogalactan possessed a highly branched structure with the anhydro-D-galactose units being joined by 1 → 3 and 1 → 6 glycosidic bonds. All of theL-arabinose was present in the furanoside form as non-reducing terminal units.

ISSN:0008-4042    

DOI:10.1139/v58-110

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

2-(9-Methyl-9-fluorenyl)-propan-2-ol and 3-(9-ethyl-9-fluorenyl)-pentan-3-ol have been prepared and shown to give 9,10-dimethyl- and 9-10-diethylphenanthrene, respectively, when heated with polyphosphoric acid.

ISSN:0008-4042    

DOI:10.1139/v58-111

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The alkaloid delcosine has previously been assigned tentatively the same carbon–nitrogen skeleton as lycoctonine to which it appears to be closely related in properties. Oxidation experiments now reported provide supporting evidence of the presence of two vicinal tertiary hydroxyl groups attached to a five- and a six-membered ring that are directly linked together at the two carbons carrying the hydroxyls. There is a methoxyl in a position β to the tertiary hydroxyl of the six-membered ring. Evidence is also provided as to the size of the heterocyclic ring and the presence of a methylene group next to the nitrogen.

ISSN:0008-4042    

DOI:10.1139/v58-112

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Trichloroacetonitrile reacts with primary and secondary aliphatic and primary aromatic amines to give N-substituted trichloroacetamidines. A series of N-mono- and N-di-substituted trichloroacetamidines,andwas prepared by carrying out the reaction in water, in water–methanol solutions, or in the absence of solvents.

ISSN:0008-4042    

DOI:10.1139/v58-113

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The preparations and bacteriostatic activities of some sulphonamide derivatives of the bicyclic guanidines are described. Some l-(2-hydroxy-3-(aryloxy)propyl)-2,3,5,6-tetrahydro-1-imidaz(1,2-a)imidazoles have also been prepared.

ISSN:0008-4042    

DOI:10.1139/v58-114

出版商:NRC Research Press    

年代:1958

数据来源: NRC