摘要:

Three monosubstituted hydroxyethyl ethers ofD-glucose have been synthesized by a novel method involving reduction of the corresponding carboxymethyl derivatives with lithium aluminum hydride. This technique also allowed introduction for the first time of hydroxyethyl substituents containing polyethylene oxide chains of a definite length in the glucose molecule, as exemplified by the synthesis of 3-O-hydroxyethoxyethyl-D-glucose.

ISSN:0008-4042    

DOI:10.1139/v56-079

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The 2-, 3-, and 6-O-carboxymethyl-D-glucoses and the 2,3-di-O-carboxymethyl-D-glucose have been synthesized. A solvent system was found which gave complete paper chromatographic separation of these derivatives as well as of those obtained upon hydrolysis of a carboxymethylcellulose.

ISSN:0008-4042    

DOI:10.1139/v56-080

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Magnesium sulphate monohydrate prepared by vacuum dehydration of the heptahydrate does not yield a pattern of X-ray diffraction lines, and in this sense may be said to have an amorphous character. By measurement of the heats of solution of the “X-ray amorphous” and crystalline monohydrates, the heat of transition has been found to be 6550 cal. mole−1. Cobaltous chloride monohydrate prepared by vacuum dehydration appears to be microcrystalline. The heat of transition to the normal crystalline form is 1390 cal. mole−1. These values are related to the surface areas of the vacuum dehydrated products.

ISSN:0008-4042    

DOI:10.1139/v56-081

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Rates of dehydration under vacuum, and at a series of controlled water vapor pressures, have been carried out for powdered samples of magnesium sulphate heptahydrate and of cobaltous chloride hexahydrate. It has been found for the magnesium salt that as the pressures are increased, the rate at first drops rapidly, this decrease being followed by a period of acceleration which is followed in turn by a decline. The curves are similar to those previously reported for copper sulphate pentahydrate, but the changes occur over a much wider range of water vapor pressures. In the dehydration of cobaltous chloride hexahydrate the initial drop in rate with increase in water vapor pressure is not observed. The results are interpreted in terms of the crystallization of intermediate products in the presence of adsorbed water.

ISSN:0008-4042    

DOI:10.1139/v56-082

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Strong alkalies are powerful catalysts for the initial oxidation of tetralin but their catalytic activity is rapidly replaced by an inhibiting action which makes oxidation of more than 5% of the tetralin an exceedingly slow process. Inhibition is due to the base catalyzed enolization and oxidation of the initial product, 1-tetralone, to various naphtholic compounds. Ring scission yields β-2-carboxyphenylpropionic acid. The rate shows a certain periodicity which may be due to the reaction proceeding by a series of consecutive autocatalytic steps.

ISSN:0008-4042    

DOI:10.1139/v56-083

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The surface pressure–area relationships of gaseous myristic acid films at the air–aqueous interface have been measured at very low surface pressures. The acid was spread from petroleum ether solutions. The molecular cohesion was found to be about six times that of gaseous butane under comparable conditions. Some explanation of Moss and Rideal’s “double molecule” phenomenon is given.

ISSN:0008-4042    

DOI:10.1139/v56-084

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The vibrational sum rule has been applied to the fluoro-chloro-bromo-ethylenes and good agreement obtained between observed frequency sums and those calculated on the basis of additivity considerations. Two unobserved frequencies fortransdibromoethylene have been calculated and the in-plane and out-of-plane sums for some molecules not yet investigated. Several ambiguities with regard to some halogenated ethylenes have been resolved and several assignments which merit reinvestigation have been indicated.

ISSN:0008-4042    

DOI:10.1139/v56-085

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

An analysis has been made of the heats of formation and combustion of organic gases and liquids, and of the heats of vaporization of liquids. The work has been done as far as possible with homologous series, in order to discover systematic effects. The data are converted into heats of atomization, i.e., the heats required to convert the gases or liquids into their constituent atoms. It is shown that the heats of atomization of the gaseous aliphatic hydrocarbons (paraffins, olefins, and acetylenes) can be accurately represented by a scheme in which a distinction is made between primary, secondary, and tertiary carbon–hydrogen bonds, and between bonds that are next to, and next but one to, multiple bonds. For aromatic molecules an appropriate correction for resonance is proposed. For other types of compound it is found that suitable values for the various bonds (e.g., C–CHO, C–OH) will give rise to good agreement with experiment.It is shown that to a reliable approximation heats of vaporization are also amenable to the same treatment. Since this is so it is possible to assign bond values on the basis of which it is possible to make predictions about heats of formation of liquids.A system of coefficients is worked out by means of which the numbers of atoms of various kinds in a molecule can be expressed in terms of the numbers of the different kinds of bonds. On the basis of these it is shown how bond contributions to heats of formation and heats of combustion can be calculated. A table (Table X) gives the contributions proposed for the heats of atomization, heats of formation, and heats of combustion for both gases and liquids.

ISSN:0008-4042    

DOI:10.1139/v56-086

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A process is described for the formation of supercooled liquid solutions by the sublimation of solid mixtures—the liquids formed being supercooled in the sense that they can be condensed from the vapor phase above solid mixtures at temperatures below the eutectic values. The process can be thought of as proceeding, solids → mixed vapor → supercooled liquid solutions. The general nature of this phenomenon in organic systems of the simple-eutectic type is established as a result of the microscopic and macroscopic experiments performed in this investigation. AP/T/cspace-model of a typical binary, eutectic-type, organic system,o-nitrophenol-naphthalene, is presented. A physical picture of the process under consideration is made possible on the basis of this model.

ISSN:0008-4042    

DOI:10.1139/v56-087

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The hydrogen overpotential of pure and impure aluminum in 0.1 NH2SO4at 25° has been studied. The effect of the autocorrosion of the metal has been interpreted and the role of impurities in determining the overpotential and the rest potential has been shown. As well, the build-up and decay of the overpotential has been studied; the behavior is much more complicated than that of noble metals.

ISSN:0008-4042    

DOI:10.1139/v56-088

出版商:NRC Research Press    

年代:1956

数据来源: NRC