摘要:

The infrared spectra of concentrated performic and peracetic acids were measured in the rock-salt region. The most significant features are theO—H stretching frequency at 3310–3350 cm−1and the OH bending frequency at 1450 cm−1which, for both peracids, remain essentially the same in the vapor state as in the liquid or in solution in nonpolar solvents. This is attributed to intramolecular hydrogen bonds resulting in particularly stable five-membered rings,Steric conditions in the percarboxylic group are favourable to such ring formation orchelation. From the observed frequency shifts the energy of these hydrogen bonds is estimated to be about 7 kcal. per mole. No evidence for unchelated molecules was found even in very dilute solutions of peracetic acid in nonpolar solvent nor in the vapour at low pressure and moderate temperature. Tentative assignments of the other frequencies in the spectra of the peracids are made by comparison with those of formic and acetic acids.The danger involved in handling these peracids in concentrated form is emphasized.

ISSN:0008-4042    

DOI:10.1139/v52-099

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The molecular weight of lysozyme has been redetermined by the ultracentrifuge as 14,100 ± 500. The molecule appears to be a stubby prolate ellipsoid of rotation, with a maximum length of 90 Å and a minimum equatorial diameter of about 18 Å depending on the degree of hydration assumed. Alternative possibilities of chain orientation within this shape are discussed assuming that the chains are coiled in Pauling–Corey helices.

ISSN:0008-4042    

DOI:10.1139/v52-100

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Compounds with the composition of tetraminates were prepared from the tetrachlorides of silicon, germanium, tin, and titanium with triethylamine. Thermal decomposition of the tetraminates leads to the suggestion that they are molecular addition compounds.

ISSN:0008-4042    

DOI:10.1139/v52-101

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Aminates of tin tetrachloride and titanium tetrachloride are reported. On the bases of these compounds, and the recovery of a tetraminate, SiCl4•4EtNH2, from among the substitution products in the reaction of silicon tetrachloride with ethylamine at −78 °C., it is suggested that the transition state in the substitution reaction corresponds to an addition compound.

ISSN:0008-4042    

DOI:10.1139/v52-102

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

2-Methyl-1,4-naphthoquinone (menadione or vitamin K3) has been synthesized labeled with C14in the methyl group. Starting with 0.2 mc. of radioactive sodium carbonate, the intermediate compounds 2-naphthoic acid-carboxyl-C14, 2-naphthalenemethanol-C14, and 2-methyl-C14-naphthalene were prepared. Oxidation of the latter compound by chromic oxide yielded 2-methyl-C14-1,4 naphthoquinone with specific activity of 3.3 × 105counts per min. per mgm. using a gas-flow type Geiger-Müller counter. Over-all yield was 23%.

ISSN:0008-4042    

DOI:10.1139/v52-103

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The variation of density with height has been determined for xenon confined in a long vertical bomb under near critical conditions. The densities were deduced by means of radioactive tracer techniques. Radioactive Xe127was added to ordinary xenon and counting rates (assumed proportional to local densities) were measured at various positions along the bomb. The observed density distributions can be entirely explained by the influence of gravity on the system; a comparison of the observed density distribution with that calculated using the measuredPVisotherms for xenon shows satisfactory agreement.

ISSN:0008-4042    

DOI:10.1139/v52-104

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Solution of cellulose trinitrate in dry pyridine containing an excess of hydroxylamine base caused the evolution of 1 mole of nitrogen gas of 99% purity and the formation in high yield of a fibrous cellulose substituted with 1.7 nitrate and about 0.08 oxime groups per glucose unit. The replacement of the hydroxylamine byo-methylhydroxylamine suppressed the evolution of gas in the above reaction but the product was similar except for a small substitution (about 0.2) of methyloxime groups. Replacement of hydroxylamine base by the hydrochloride altered the composition of the evolved gas to nitrous oxide, about 85%, and nitrogen, about 15%. The fibrous product, isolated in high yield, had the composition of a cellulose substituted with 1.7 nitrate and about 1 oxime groups. No gas was produced in the parallel experiments witho-methylhydroxylamine hydrochloride and the product contained 1 methyloxime instead of 1 oxime unit.The above partial denitrations involved only an incidental degradation of the cellulose trinitrate, and probably only nitrate groups in the second, or third, rather than the sixth, positions of the glucose residues. All four products had a. wide solubility in organic liquids and were remarkable for their relatively great stability toward pyridine or caustic soda.

ISSN:0008-4042    

DOI:10.1139/v52-105

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

A strain ofBacilluspolymyxahas been shown to produce two different polysaccharides when grown on a yeast extract – salts – sucrose medium in the presence of calcium carbonate. One of these polysaccharides is a levan. Methylation and hydrolysis of this compound followed by chromatographic separation on a silica column gave 1:3:4-trimethyl-D-fructofuranose, l:3:4:6-tetramethylD-fructofuranose, and 3:4-dimethyl-D-fructofuranose in the proportions 6:1.5:1 (by weight). A possible formula is suggested.

ISSN:0008-4042    

DOI:10.1139/v52-106

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The rate of decomposition of hypochlorous acid has been measured in aqueous solution in the presence of much sodium hypochlorite. The rate is nearly independent of the hypochlorite concentration, and proportional to the square of the hypochlorous acid concentration. Hence the mechanism proposed isThe first step is the slower. The reactionalso occurs, but is much slower. Oxygen is also evolved, by a first order reaction. Values for the rate constants at different temperatures of all these reactions are given. Measurements are also reported on certain equilibria present in these solutions: the ionization of hypochlorous and chlorous acids, and the reaction.Details of modified analytical methods for hypochlorite and chlorate in the presence of chlorite are given.

ISSN:0008-4042    

DOI:10.1139/v52-107

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The heat capacity of nitrogen adsorbed on titanium dioxide has been measured for amounts adsorbed corresponding to 2.2, 3.1, 4.0, and 4.8 molecular layers in the temperature range 14 ° to 75 °K. The occurrence in the adsorbed films of melting and of the transition in the solid phase of nitrogen is shown by maxima in the heat capacity. The melting process is completely reversible and takes place at temperatures below the normal melting point. The solid phase transition does not occur reversibly, the magnitude of the anomaly in the heat capacity depending upon the extent to which the system has been cooled prior to the measurement of the heat capacity. The experimental results are discussed in terms of current thermodynamic treatments of phase transitions in adsorbed films.

ISSN:0008-4042    

DOI:10.1139/v52-108

出版商:NRC Research Press    

年代:1952

数据来源: NRC