摘要:

The kinetics of silver – silver ion exchange have been studied with etched silver foils. The results indicate that several different rates of reaction occur on a single specimen. This may be interpreted to indicate the presence of crystal faces of different orientations, each of which exchange at a given rate. Interchange of ions in solution with radioactive ions adsorbed on the metal surface was not distinguishable from exchange between ions in solution and active atoms of the metal. When adsorbed silver ions were electrodeposited, the resulting metal surface exhibited a completely heterogeneous character with respect to exchange.

ISSN:0008-4042    

DOI:10.1139/v53-074

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Reaction of equivalent amounts of pentaacetyl-β-D-glucopyranose and methanol in benzene or chloroform solution in the presence of 0.5 or more moles of stannic chloride per mole of methanol gave 50-60% yields of methyl tetraacetyl-β-D-glucopyranoside. α-Acetochloroglucose was a by-product of the reaction. The mechanism of the reaction is discussed. The method was applicable for the preparation of phenyl tetraacetyl-β-D-glucopyranoside.

ISSN:0008-4042    

DOI:10.1139/v53-075

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The α- and β-2-methoxycyclopentylmercuric chlorides, bromides, and iodides have been prepared. The X-ray powder patterns, dipole moments, and thermal analyses among each series have been compared with the homologous methoxycyclohexyl derivatives. In both of the series the dipole moments of the β-diastereomers are greater than those of the corresponding α -isomers. In both series the α- and β-diastereomers seem to comprise isostructural series among the three halides. This isostructural relationship seems to be reflected in the melting point composition diagrams.

ISSN:0008-4042    

DOI:10.1139/v53-076

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The permanganate oxidation product of annotinine is shown to be an amide that contains the ether ring of annotinine still intact. The Clemmensen reduction of this compound to the saturated base, C16H23O2N, was re-examined. A number of intermediates were isolated from the system and these were also prepared from the oxidation product by other methods. Analogous reactions of annotinine chlorohydrin were also studied. From these results suggestions are presented regarding the size of the ether ring and its position relative to the nitrogen atom.

ISSN:0008-4042    

DOI:10.1139/v53-077

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Cotton linters dewaxed with benzene and alcohol possess a slightly expanded structure attributed to the swelling effect of the alcohol. Storage causes a partial collapse of the linters especially so when moisture is present. Wetting with water followed by rigorous drying produces a marked reduction in accessibility, but with each additional wetting–drying cycle accessibility of the dried linters increases slightly as measured by reaction with thallous ethylate in ether, a nitration mixture, and in hydrogen–deuterium exchange. Differences in nitration found for limited reaction times are obliterated when these reaction times are extended. Increasing accessibility due to repeated wetting and drying is accompanied by lower water sorption and smaller heats of wetting. This anomaly is due to the fact that cellulose samples obtained by alternately wetting and drying dewaxed linters, when stored with a desiccant, compete for the limited amount of water present and adsorb moisture in proportion to their accessibility. Upon further exposure to water the sample of least accessibility, having adsorbed less water, can now adsorb to a greater extent than do the linters of somewhat greater accessibility.The evidence indicates that the difference in accessibility occasioned by repeated wetting and drying is of a physical rather than chemical nature.

ISSN:0008-4042    

DOI:10.1139/v53-078

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Aliphatic 2-furylketones rearrange to 3-hydroxy-2-alkylpyridines under the influence of ammonia and heat. The furylketones were prepared by a modified Friedel-Crafts reaction. Conditions to obtain the pyridine derivatives in good yield have been established.

ISSN:0008-4042    

DOI:10.1139/v53-079

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Liquid–vapor coexistence curves of ethane, ethylene, and xenon have been measured in the region of the critical point. Impurities present in the ethane and ethylene gave retrograde systems; reduction of the impurities yielded coexistence curves which were flat along the temperature axis to 0.001 °C. When the height of the ethylene system was decreased the range of densities over which the curve was flat was diminished. Stirring of the system caused the curve to be rounded. Similar results, confirming those of Weinberger and Schneider, were obtained with xenon. The observed behavior is in good agreement with the hypothesis that the major part of the flat top effect is due to gravitational compression.

ISSN:0008-4042    

DOI:10.1139/v53-080

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Methane, benzene, andp-toluene sulphonic acids react instantaneously at room temperature with dicyclohexyl and di-p-tolyl carbodiimides to form the corresponding sulphonic anhydrides, VI, and disubstituted ureas, VII. The use of di-p-tolyl carbodiimide affords a convenient general method of preparation of sulphonic anhydrides.

ISSN:0008-4042    

DOI:10.1139/v53-081

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Kinetic data for the solvolysis of parasubstituted methyl, ethyl, and isopropyl benzenesulphonates in ethanol, methanol, methanol–water, and dioxane–water mixtures have been determined. It has been shown that the effect of the ionizing properties of the solvent of α-methylation, and of the addition of a strong base show the same general characteristics which for the halides have been considered diagnostic of a change in mechanism from a bimolecular solvolysis to a reaction in which ionization is rate controlling. The changes in the relative effect of para-substituents which accompany the apparent change of mechanism are examined. The greater effect of the para-NO2substituent over the meta-NO2substituent for the isopropyl esters under ionizing conditions is attributed to the contribution of resonance stabilization in forming ion.

ISSN:0008-4042    

DOI:10.1139/v53-082

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The formation of AcAn from PHX, nitric acid, and acetic anhydride has been investigated at various temperatures. The effects of added acetic acid and added salts have been determined. While the reaction is first order with respect to PHX, it is of an order 2.6 with respect to nitric acid. The reaction rate is significantly decreased by small concentrations of sodium nitrate. The reaction is also characterized by a secondary salt effect and a low apparent activation energy of about 2 kcal. mole−1. A mechanism has been suggested in qualitative, and to some extent quantitative, agreement with the experimental data. It is postulated that the conversion of PHX involves a rate-controlling ionic reaction between PHX and nitric acid, and that this is followed by a rapid acetylation of the acidic intermediate to AcAn.

ISSN:0008-4042    

DOI:10.1139/v53-083

出版商:NRC Research Press    

年代:1953

数据来源: NRC