摘要:

L-Glucoheptulose has been prepared by the action of muscle aldolase on a mixture ofL-erythrose and hexose diphosphate.

ISSN:0008-4042    

DOI:10.1139/v56-010

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The synthesis of toluene-α-d3,o-chlorotoluene-α-d3, andm-xylene-α,α′-d6from benzotrichloride,o-chlorobenzotrichloride, and α,α′ hexachloro-m-xylene respectively is reported using zinc and acetic acid-das the dechlorinating agent. The preparation of acetic acid-dof optimum isotopic purity is described.

ISSN:0008-4042    

DOI:10.1139/v56-011

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A study of the reactions of trifluoromethyl radicals, produced by the photolysis of hexafluoroacetone, with propane,n-butane, and isobutane has been made. The rate constants of the hydrogen-abstraction reactions have been determined at temperatures between 27 °C and 119 °C and the activation energies found to be 6.5 ± 0.5, 5.1 ± 0.3, and 4.7 ± 0.3 kcal./mole respectively. These values are compared with those obtained for the reactions with methane and ethane, and with the corresponding reactions of methyl radicals.

ISSN:0008-4042    

DOI:10.1139/v56-012

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A study of the polymerization of styrene in the presence of either α- or β-bromostyrene at 45 °C and 70 °C has shown that copolymerization does not occur. From the variation of molecular weight and rate of polymerization with bromostyrene concentration it is concluded that the bromostyrenes behave essentially as efficient transfer agents.

ISSN:0008-4042    

DOI:10.1139/v56-013

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The photolysis of ketene in the presence of hydrogen has been investigated in the temperature range −40° to 207 °C. The main products are CO, C2H4, C2H6, and CH4, with some methyl ethyl ketone at the higher temperatures. Hydrogen and ketene compete for CH2radicals by the reactionswithE3 − E2 = 0.8 kcal. At the higher temperatures the reactionleads to a chain reaction viaThe value ofE6is found to be 10.2 ± 0.5 kcal. in good agreement with previous work.

ISSN:0008-4042    

DOI:10.1139/v56-014

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A tracer study has been made of acetal formation and hydrolysis. Benzaldehyde andn-butyraldehyde, enriched in O18, on reaction withn-butyl and allyl alcohols, gave acetals of normal isotopic abundance. The label appeared in the water of condensation. Hydrolysis of benzaldehyde di-n-butyl acetal andn-butyraldehyde di-n-butyl acetal in O18enriched water gave alcohols of normal isotopic content. A slight enrichment due to isotopic exchange was found in allyl alcohol produced by the hydrolysis of benzaldehyde diallyl acetal. These results establish that the reversible reaction proceeds by a fission of the aldehyde-carbon to oxygen bond.

ISSN:0008-4042    

DOI:10.1139/v56-015

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Mercaptoacetic acid (MAA) in acid copper sulphate electrolyte decreased the cathode polarization throughout the course of electrolysis at all concentrations up to 20 mgm./liter. Addition of small amounts of chloride caused further depolarization. When present together with cystine, MAA showed an independence of action. The depolarization caused by MAA was ascribed to a decreased activation overpotential due to substitution of a more readily dischargeable MAA–copper complex for the aquo–copper complex. The additional depolarization due to chloride was ascribed to formation of a still more readily dischargeable chloro–MAA–copper complex. The depolarization in both cases increased with time during prolonged electrolysis, apparently due to surface roughening with, presumably, a consequent increase in surface area and decrease in true current density.

ISSN:0008-4042    

DOI:10.1139/v56-016

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The crystal structures of the following binary intermetallic compounds of plutonium are reported: PuAl2, PuAl3, PuAl4, PuBe13, PuCo2, PuFe2, PuMn2, PuNi2, PuNi5, and Pu2Ni17. In addition, the unit cell dimensions are reported for PuAg3.

ISSN:0008-4042    

DOI:10.1139/v56-017

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A theoretical treatment is worked out for the kinetic schemein which two enzyme–substrate complexes are formed consecutively. The steady-state rate equations are obtained, and equations are given for the transient phase subject to the condition that the substrate concentration is greatly in excess of that of the enzyme. Some kinetic consequences of the resulting equations are discussed.

ISSN:0008-4042    

DOI:10.1139/v56-018

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

This paper is devoted to the direct determination of the vapor pressures of solutions of the nitrates of silver, of ammonium, and of lithium, at temperatures varying from 30 °C. to 105 °C. and at concentrations varying from 10 to 85 weight % (for lithium nitrate, the limited solubility precluded measurements beyond 65%). From the vapor pressures, the enthalpies of evaporation of water (by a modification of the Clapeyron–Clausius equation), the differential heats of dilution, and the activities of water (as compared with the mole fractions of the solvent) have been calculated. From the results we conclude that the water of hydration of the ammonium and silver ions (if, indeed, these ions are hydrated at all) is very loosely attached, while that of the lithium ion is strongly bound.

ISSN:0008-4042    

DOI:10.1139/v56-019

出版商:NRC Research Press    

年代:1956

数据来源: NRC