摘要:

The synthesis of hexafluoroacetone reported recently by Brice, Lazerte, Hals, and Pearlson has been improved in several particulars. Teflon was depolymerized to tetrafluoroethylene which was then dimerized to give a 50% yield of perfluoroisobutene in one step. Oxidation of the latter at 35–40 °C. with aqueous potassium permanganate gave a 75% yield of hexafluoroacetone hydrate. The vapor pressure of hexafluoroacetone was measured between −60 ° and −28 °C.

ISSN:0008-4042    

DOI:10.1139/v55-055

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The pyrrole IIewas obtained through the known IIcand hydrolyzed to IIIb. This last could be partially decarboxylated to hemopyrrole-dicarboxylic acid IIIcor, with formic acid, converted into the dipyrromethene VIIb. The isomeric dipyrromethene VIIawas obtained analogously.

ISSN:0008-4042    

DOI:10.1139/v55-056

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Some simple pyrroles form stable hydrobromides. Their formation may interfere with some reactions, but offers analytical possibilities.

ISSN:0008-4042    

DOI:10.1139/v55-057

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The reactions between CH3 + CH3—Hg—CH3were investigated in a system in which acetone was used as the source of CH3radicals. Similarlyd6-acetone was used to investigate the reactions of CD3radicals and CH3—Hg—CH3. Activation energies for the hydrogen abstraction reactions were calculated, and no significant difference was found between the CD3and CH3reactions, being respectively 10.0 and 10.2 kcal./mole. Under conditions of constant intensity and acetone concentration, reaction rates appear to be dependent on mercury dimethyl concentrations. In the case of the acetone-d6system, quantities of C2D3H3were found in the reaction products. This is discussed as possible evidence of such a reaction as:

ISSN:0008-4042    

DOI:10.1139/v55-058

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Carrageenin was fractionated with potassium chloride and by successive extractions at elevated temperatures. Measurements were made of sulphate content, optical rotation, gel strength, intrinsic viscosity, sedimentation rate, and ionic mobility. The results indicated three components extractable at 30 °C., 60°C., and 100–120 °C. The 60 °C. extract had a high gel strength while the components extracted at 30 °C. and 100–120 °C. showed low gelling tendencies. The two non-gelling components were concentrated in the supernatant liquid when fractionated with potassium chloride.

ISSN:0008-4042    

DOI:10.1139/v55-059

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The photo-oxidation of azomethane has been studied at low oxygen pressures (0.02 to 1 mm.) in the temperature rangeca. 25 °C. to 161 °C. The primary process in the normal photolysis of azomethane is essentially unaffected by the presence of oxygen. Carbon monoxide is probably a secondary product of the oxidation of methyl radicals. Carbon dioxide formation is quite small, and therefore neither methyl radicals nor CH3N=N—CH2radicals are oxidized appreciably to carbon dioxide. Nitrous oxide, which is a major product of the oxidation, is most likely formed from the oxidation of CH3N=NCH2radicals. The suggested mechanism of N2O formation is:The reaction of methyl radicals with oxygen was found to proceed with a negligible activation energy and a steric factor of the order of 10−2. Evidence for the occurrence of the reactionsat room temperature was obtained.

ISSN:0008-4042    

DOI:10.1139/v55-060

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The preparation of dicyanodiacetylene as reported by Moureu and Bongrand has been investigated more fully and a procedure developed whereby yields as high as 36% have been obtained.

ISSN:0008-4042    

DOI:10.1139/v55-061

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

There is no ternary eutectic in the system: indium–lead–tin: the eutectic trough extends from the lead–tin eutectic to the tin–indium eutectic. The liquidus surface has been outlined. The structures of all alloys of the above system have been investigated, at room temperature, by the X-ray and microscopic techniques. A one-phase region extends across the ternary diagram from the limits of the β-phase in the indium–tin system to the limits of the β-phase in the lead–indium system. This indicates that the intermetallic β-phases of the two systems (lead–indium and tin–indium) have the same lattice structure, viz. face-centered tetragonal. Heterogeneity has been detected by direct experiment in the system lead–indium, whereas it had previously only been deduced. Hardness tests, both Brinell and Vickers, have been made on the alloys.

ISSN:0008-4042    

DOI:10.1139/v55-062

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The absorption spectrum of hydrogen peroxide was re-examined with a prism instrument in the region 1.5 to 25 μ. A pair of well-resolved perpendicular bands arising from torsional oscillation of the OH groups were found centered about 460 and 575 cm.−1. The overtone band at 3.8 μ was shown to be a hybrid with prominent rotational structure and some indications of doubling. Its assignment to the combination ν2+ν6implies a positive anharmonicity. Four new overtone bands were observed in liquid hydrogen peroxide. The infrared spectrum of deuterium peroxide was measured for the first time in the solid and vapor states. The vapor bands are quite different in appearance from those of hydrogen peroxide. One of the fundamentals, the asymmetric O—D stretching at 2661 cm−1, was resolved sufficiently to allow calculation of the rotational constants of the isotopic molecule. Mixtures of the two peroxides containing around 40% of HDO2were also investigated; from the results the frequency of the as yet unobserved symmetric modes ν1and ν2could be estimated with fair certainty. The O—O stretching vibration at 11μ was too weak to be located definitely in the spectra of the gaseous peroxides. The structural parameters of the H2O2molecule are now established as follows:The O—H and O—D stretching bands were studied in solutions of the three isotopic peroxides in carbon tetrachloride.

ISSN:0008-4042    

DOI:10.1139/v55-063

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Rates of dehydration under full vacuum, and also as the pressure of water vapor due to the dehydration process was allowed to increase, have been determined for a number of hydrated salts. The dehydration of manganous sulphate tetrahydrate, zinc sulphate heptahydrate, nickel sulphate hexahydrate, and magnesium sulphate heptahydrate has been found to proceed through the formation of amorphous intermediates, the last two of these being very stable. The dehydration of nickel nitrate hexahydrate, magnesium nitrate hexahydrate, and probably of ferrous sulphate heptahydrate and cobalt chloride hexahydrate at very low pressures takes place with the formation of crystalline intermediates. The results obtained are discussed in relation to the dependence of rate of dehydration on water vapor pressure previously reported for copper sulphate pentahydrate and for manganous oxalate dihydrate.

ISSN:0008-4042    

DOI:10.1139/v55-064

出版商:NRC Research Press    

年代:1955

数据来源: NRC