摘要:

When linseed oil or other oils containing linolenic acid are hydrogenated, an isomeric linoleic acid (isolinoleic acid) is formed. Its concentration increases to a maximum, then decreases as hydrogenation proceeds. In view of the possible relationship of this acid to "flavor reversion", its separation in pure form has been investigated. Concentrates of isolinoleic acid or its methyl ester were obtained from partially hydrogenated linseed oil by crystallizing a large proportion of the more saturated acids or methyl esters from a solvent at low temperatures. Further fractionation of such concentrates by chromatographic methods was investigated. Silica gel was found to be better for the purpose than either activated alumina or activated carbon. Methyl isolinoleate was adsorbed more firmly on the silica gel than the less unsaturated esters, which were eluted by means of large volumes of hexane. Subsequent elution with chloroform removed the methyl isolinoleate.

ISSN:1923-4287    

DOI:10.1139/cjr49b-059

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The infrared absorption spectrum of methyl isolinoleate, separated from the methyl esters of hydrogenated linseed oil fatty acids, has a well defined absorption band with maximum absorption at about 968 cm.−1As an identical band was found in the spectra of fatty acids or esters after isomerization with selenium, it is attributed to the presence of double bonds with atrans-configuration. It was found that the same band was present in the spectra of samples taken during hydrogenation of oils, and that its intensity increased to a maximum, then decreased as hydrogenation proceeded. It is concluded that hydrogenation is accompanied by acis-to-transchange in some of the double bonds of the fatty acids, and that methyl isolinoleate has at least one double bond with atrans-configuration.

ISSN:1923-4287    

DOI:10.1139/cjr49b-060

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The flow properties of dispersions of calcium soaps in hydrocarbon oils have been studied over a range of temperature from 35° to 90 °C., and rates of shear from 500 to 16,000 sec.−1by extrusion through a capillary plastometer. The thixotropy of the system falls as the temperature is increased to 50 °C. and then rises to a maximum at 65 °C., after which it falls regularly. This behavior is due to the thermal weakening of the thixotropic bonds, followed by a strengthening of these bonds due to incipient swelling on the surface of the soap. As the surface of the soap particles continues to swell, cohesion of the particles increases to such an extent that breakdown does not take place and the coefficient of thixotropy falls to very small values. The coefficient of thixotropy found by this method bears a linear relation to the hardness of the dispersion as determined by a falling cone.

ISSN:1923-4287    

DOI:10.1139/cjr49b-061

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Labeled sodium glycerophosphate has been prepared by phosphorylating glycerol with sodium dihydrogen phosphate containing P32. After the labeled sodium glycerophosphate had been fed to a laying hen, radiophosphorus from glycerophosphate appeared in the shells, whites, and yolks of the eggs. The uptake in different eggs followed a pattern similar to that found for inorganic phosphate, the maximum occurring at the fourth or fifth egg. Comparative studies using P32labeled sodium glycerophosphate and trisodium phosphate indicate that the rate of utilization of the phosphorus from glycerophosphate is less than the rate of utilization of the phosphorus from inorganic phosphate. The possibility of an enzymatic hydrolysis of glycerophosphate followed by the incorporation of the resulting phosphoric acid into the phospholipids and the phosphorylation of lower glycerides (partially hydrolyzed fat) by inorganic phosphate as a mechanism for phospholipid formation is discussed.

ISSN:1923-4287    

DOI:10.1139/cjr49b-062

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

A study has been made of the solubility of uranyl nitrate hexahydrate and thorium nitrate tetrahydrate in various organic solvents at 20 °C. In all the solvents investigated no case was found where the thorium nitrate tetrahydrate was more soluble than the uranyl nitrate hexahydrate. Hydrocarbons do not dissolve either compound to an appreciable extent. Addition of a ketone, aldehyde, or alcohol group enhances the solubility considerably. The simpler the compound the greater the solubility of the nitrate in any given family.

ISSN:1923-4287    

DOI:10.1139/cjr49b-063

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The synthetic oestrogens, stilboestrol, hexoestrol, and dienoestrol give color reactions with nitric and nitrous acids, bromine, and certain phenol reagents, some of which can be adapted to their colorimetric determination. The use of Folin and Ciocalteu's phenol reagent is described for determination of the hormones in pharmaceutical products, using a Lumetron photoelectric colorimeter. The interference of other oestrogens and of phenolic preservatives and bactericides is considered and reference is made to a means of identifying the hormones by color reactions with antimony pentachloride in ethylene dichloride, and with an acetic – phosphoric acid reagent.

ISSN:1923-4287    

DOI:10.1139/cjr49b-064

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Aside from small uncrystallized residues the only alkaloids found inDendromecon rigidaBenth. are protopine and allocryptopine.

ISSN:1923-4287    

DOI:10.1139/cjr49b-065

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

An investigation of the dinitration ofp-cymene (4-isopropyltoluene) has been carried out, with particular regard to determining the effects of varying the temperature, the nitric acid, sulphuric acid, and water contents of the system, the rate of addition ofp-cymene, and the stirring time upon the yields of 2,6-dinitrocymene and 2,4-dinitrotoluene. Optimum nitrating conditions have been determined and the relative constancy of the dinitrocymene: dinitrotoluene ratio over a wide range of conditions has been established. Yields of the order of 55% dinitrocymene and 25% dinitrotoluene have been obtained. Various theories are offered with a view to explaining some of the more important observations.

ISSN:1923-4287    

DOI:10.1139/cjr49b-066

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The intrinsic "vistex" viscosities of several series of butadiene–styrene copolymers of varying conversion and average molecular weight, dissolved directly from the latex in the vistex solvent mixture (toluene–isopropanol, 80/20 by volume), have been investigated and compared with the intrinsic viscosities of the corresponding coagulated, dried polymers dissolved in toluene. The intrinsic viscosity in toluene, [η]T, is related to the intrinsic vistex viscosity, [η]V, in toluene–isopropanol by the equation:—Hence, viscosity average molecular weight may be calculated from vistex measurements.A further development of the method has shown that, once the latex is dissolved in the vistex solvent, the solution may be diluted, within certain denned limits, by the addition of pure solvent (toluene) to obtain the several levels of concentration of polymer required for the determination of intrinsic viscosity. It is then possible, by extrapolation to zero concentration of polymer, to obtain a value for the intrinsic viscosity that is equal to the conventional intrinsic viscosity of the polymer in pure solvent after coagulation and drying under very mild conditions. The viscosity characteristics of butadiene–styrene copolymers of varying conversion appear to be represented, at conversions below the gel point, by the equation,where β′ andnare constants of the order of 0.25 and 1 for solutions in toluene and 0.1 and 2.5 respectively for vistex solutions. Distinct changes in β and/ornhave been found at conversions in the region of and beyond the gel point.

ISSN:1923-4287    

DOI:10.1139/cjr49b-067

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The mechanism suggested by Gurney for the formation of a double layer at the interface of a metal and a solution containing its ions is applied to a diffuse double layer. The diffuse part of the double layer is treated in a way that differs from Stern's method, leading to a more convenient formula for the potential ψδof the diffuse part. Numerical values and a comparison with Stern's results are given.

ISSN:1923-4287    

DOI:10.1139/cjr49b-068

出版商:NRC Research Press    

年代:1949

数据来源: NRC