摘要:

The decomposition of ethyl mercaptan to ethylene and hydrogen sulphide was studied at various temperatures, with and without a catalyst. Metal sulphides (copper, nickel, and cadmium) proved to be the most efficient catalysts for cracking ethyl mercaptan into unsaturated end products, the optimum temperature being 500–600 °C. When no catalyst was used a 40–50% yield of ethylene and a nearly quantitative conversion to hydrogen sulphide was observed between 600 and 700 °C. Other products identified in the exit gas were carbon disulphide, carbonyl sulphide, methane, hydrogen, ethane, thiophene, diethyl sulphide, and free sulphur. Identification of these products was aided by infrared and mass spectral analysis of the gas. A tentative mechanism for the reaction justifying the presence of the above by-products is outlined.

ISSN:0008-4042    

DOI:10.1139/v55-155

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

A direct preparation of symmetrical saturated monoacid diglycerides is described. The synthesis involves the preparation of 2-O-benzylglycerol, acetylation, interesterification with either methyl stearate or methyl palmitate, and hydrogenolysis to yield the desired 1,3-diglyceride. The melting points of the symmetrical diglycerides are slightly higher than those obtained previously by other methods of synthesis which involve a 1,2 to 1,3 shift of acyl groups.

ISSN:0008-4042    

DOI:10.1139/v55-156

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The alkaloidal extract fromLupinuspilosusWalt. was found to contain two alkaloids, one widely occurring one,d-lupanine, and one which had already been reported to occur in this plant, i.e.,d-epilupinine, but no lupinine. The alkaloid tetralupine has been found by direct comparison of the bases and their corresponding salts and by their infrared absorption spectra to be identical withdl-epilupinine. A study of the infrared absorption spectra of lupinine andepi-lupinine leads to the same conclusion as the chemical evidence, i.e., that in the former the hydroxymethylene group occupies the axial position whereas inepilupinine this group is in the equatorial position.

ISSN:0008-4042    

DOI:10.1139/v55-157

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

A method believed to hydrolyze peptide bonds of proteins selectively at the amino groups of serine was used to obtain polypeptides from wheat gluten. The procedure involved the use of strong acid and introduced appreciable amounts of sulphur into the products possibly as sulphonic acid groups. Most of the serine appeared at the amino termini of the peptides. The peptides displayed a striking electrophoretic homogeneity which may at least in part be accounted for by the acquired acid groups. Osmotic pressure measurements indicated an average molecular weight near 20,000 and terminal group estimates indicate that each molecule contained several N-terminal serine residues. There appeared to be strong association or chemical cross linking between peptide chains of the degraded gluten.

ISSN:0008-4042    

DOI:10.1139/v55-158

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

An investigation has been made of the photolysis of liquid acetone in the temperature range from 55° to −25 °C. The quantum yields of all products are small, and decrease strongly with decreasing temperature. It is concluded that the low yields can be explained both on the basis of the 'cage effect', and by the deactivation of an excited molecule. At high temperatures and intensities the gaseous products can be accounted for on the assumption that radicals have escaped from the 'cage' and react analogously to the gas-phase mechanism. At low temperatures ethane formation in the 'cage' may be of importance.

ISSN:0008-4042    

DOI:10.1139/v55-159

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v55-160

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Fluorobutadiene has been copolymerized with styrene in emulsion at 5 °C. The rate of mercaptan consumption, rate of conversion, copolymer composition, and the intrinsic viscosity of the copolymer have been measured. Reactivity ratios and regulating indices were calculated for this temperature. Copolymerization reactions at 50 °C. were studied in solution, and the reactivity ratios calculated. These were, for the following monomers as monomer 2: styrene at 5 °C.,r1 = 1.61 ± 0.24 andr2 = 0.16 ± 0.08; styrene at 50 °C.,r1 = 1.55 ± 0.10 andr2 = 0.50 ± 0.10; acrylonitrile at 50 °C.,r1 = 0.59 ± 0.10 andr2 = 0.07 ± 0.03; isoprene at 50 °C.,r1 = 2.05±0.19 andr2 = 0.19 ± 0.10; α-methyl styrene at 50 °C.,r1 = 1.77 ± 0.19 andr2 = 0.38 ± 0.11; and methyl methacrylate at 50 °C.,r1 = 1.54 ± 0.08 andr2 = 0.64 ± 0.08. Polyfluorobutadiene has a cohesive energy density of 90–100 cal./cc., a second order transition point of −62.5 °C., and some units formed by 1,2 or 3,4 addition.

ISSN:0008-4042    

DOI:10.1139/v55-161

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The simple semiempirical molecular orbital method was applied to saturated hydrocarbons in three different approximations. Electronic charge distribution diagrams were obtained. Characteristic differences between saturated and conjugated compounds concerning bond localization and the effect of an electronegative substituent can be interpreted on the basis of these diagrams. The 1selectrons of the hydrogens are introduced for the first time in semiempirical molecular orbital calculations.

ISSN:0008-4042    

DOI:10.1139/v55-162

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The carbohydrate residues in κ-carrageenin are 3,6-anhydro-D-galactose andD-galactose which are present in nearly equal amounts. Tests following fractional precipitation of κ-carrageenin indicate general chemical homogeneity but physical heterogeneity. κ-Carrageenin is not susceptible to oxidation with periodate. Fractional precipitation of λ-carrageenin separates a main fraction which contains onlyD-galactose and a trace of 3,6-anhydro-D-galactose. This polysaccharide is susceptible to periodate oxidation. It is polydisperse on a mass basis. Materials containing glucose, xylose, andL-galactose segregate into minor fractions of λ-carrageenin and hence cannot be integral parts of the principal polysaccharides of carrageenin.L-Galactose has been isolated from carrageenin by a simple procedure.

ISSN:0008-4042    

DOI:10.1139/v55-163

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The stability of the ring structure in kojic acid toward various reagents was investigated. Cleavage to an open-chain, dienol derivative inNsodium hydroxide at 25°, or fragmentation of the structure, was very slow. The benzoyl group in the fifth (phenolic) position of dibenzoylkojic acid was removed by hydroxylamine hydrochloride in pyridine so selectively that the method was of value in synthesizing certain new derivatives. Although catalytic hydrogenation readily reduced the pyrone ring in kojic acid to undefined substances, zinc dust in glacial acetic acid reduced the hydroxymethyl group in the dibenzoate to a methyl group and yielded benzoylallomaltol. The ring in dibenzoylkojic acid was apparently opened, with retention of both benzoyl groups, by semicarbazide hydrochloride and pyridine to yield two isomeric "disemicarbazones", C22H22N6O7, decomp., 215° and 172–173°, respectively. The higher-melting isomer when boiled with dilute acid gave a compound C21H15N3O5, m.p. 244°, which was apparently cyclic; the same isomer with nitrous acid yielded two isomeric, apparently open-chain "monosemicarbazones", C21H19N3O7, decomp., 215° and 178–179°, respectively. The structures of these five compounds were not determined. The following substances were thought to be new: sodium kojate, a white powder, and its crystalline tetrahydrate; 5-hydroxy-2-(methoxymethyl)-γ-pyrone, m.p. 75–76°, and its crystalline aluminum salt, decomp. 270–271°; molecular addition compound of dibenzoylkojic acid and benzoic acid, m.p. 120–121°; 2-(acetoxymethyl)-5-benzoxy-γ-pyrone, m.p. 144°; 2-(benzoxymethyl)-5-hydroxy-γ-pyrone, m.p. 180–181°; and 2-(benzoxymethyl)-5-methoxy-γ-pyrone, m.p. 110–111°. A more convenient synthesis was discovered for 5-benzoxy-2-(hydroxymethyl)-γ-pyrone, and the published melting point was revised from 136° to 143–144°; the melting point of 5-benzoxy-2-(triphenylmethoxymethyl)-γ-pyrone was revised from 206–08° to 213–214°.

ISSN:0008-4042    

DOI:10.1139/v55-164

出版商:NRC Research Press    

年代:1955

数据来源: NRC