摘要:

p-Trifluoromethyltolane andp-fluorotolane have been synthesized by the action of sodium or potassium amide in liquid ammonia onpara-substituted 1,1-diphenyl-2-bromoethylenes. The geometrical isomers of 1-(p-trifluoromethylphenyl)-1-phenyl-2-bromoethylene have been separated and their configurations assigned on the basis of dipole moment measurements.p-Trifluoromethyltolane has been converted to a dibromide, which on oxidation gave benzoic andp-trifluoromethylbenzoic acids. Both tolanes have been reduced to the correspondingly substituted 1,2-diphenylethanes.

ISSN:0008-4042    

DOI:10.1139/v55-199

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Treatment of gliadin with sulphuric acid transposes peptide bonds of serine from the amino to the hydroxyl group. Maximum transposition, 60–70% of the theoretical, occurs when the protein is treated with anhydrous sulphuric acid at 0°C. for 35 hr. No rearrangement was detected at threonine residues. Examination of the peptide material, obtained from the rearranged protein by Elliott's degradation method, indicates apparent "homogeneity". In an alternative scheme for the degradation, nitrous acid deamination of free amino groups was used. The resulting loss in serine content of the protein is direct evidence for the acyl migration of peptide bonds. Incorporation of sulphur and partial disappearance of several amino acids accompany the sulphuric acid treatment. The occurrence of these secondary reactions imposes limitations on the use of sulphuric acid as a reagent for the specific fission of peptide bonds.

ISSN:0008-4042    

DOI:10.1139/v55-200

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The main products of the reaction between active nitrogen and azomethane were hydrogen cyanide and ethane. Traces of methane, ethylene, and acetylene were also formed, together with small amounts of an unstable product. Activation energies of about 0.5 ± 0.4 and 1.9 ± 0.3 kcal. per mole, with corresponding steric factors of 10−1to 10−3and 10−2to 10−4, were estimated for the reactions of active nitrogen with methyl radicals and azomethane respectively, on the assumption that atomic nitrogen is the reactive component of active nitrogen. Azomethane appeared to catalyze the deactivation of active nitrogen.

ISSN:0008-4042    

DOI:10.1139/v55-201

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The "coincident discharges" in a 4π-counter have been examined and found to be due in the main to gas and wall back-scattering. This can be resolved into two components—scattering near to and far from the source. Curves have been obtained for the back-scattering of β radiation by the source-mounting film and for the absorption of the incident and back-scattered radiation. Back-scattering by the film is shown to be great enough to introduce a large error into the "sandwich" method which is currently in use for correcting for source-mount absorption.

ISSN:0008-4042    

DOI:10.1139/v55-202

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The electrical response of plasticized polyvinylidene chloride has been studied over a wide range of frequency, temperature, and plasticizer content. The dispersion region was shifted to lower temperatures at a given frequency on the addition of alpha chloronaphthalene as plasticizer, but remained practically unchanged with hexachlorobenzene as plasticizer. Comparison was made with mechanical measurements for plasticized vinylidene chloride copolymers and reasonable agreement between electrical and mechanical properties was found. Enthalpies and entropies for dielectric relaxation were calculated on the theory of absolute reaction rates and were compared with values for plasticized polyvinyl chloride. A calculation of plasticizer efficiency from electrical measurements was attempted on the basis of a method suggested by Dyson. An interesting empirical relationship between enthalpy and entropy of activation and plasticizer content in polyvinyl chloride and polyvinylidene chloride is presented.

ISSN:0008-4042    

DOI:10.1139/v55-203

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Calculations of the surface energy of an undistorted {100} face of crystalline magnesium oxide have been made. An exponential form of the repulsive energy term was used, and the van der Waals attractive energy between dipoles was included, as in the Born–Mayer treatment of cohesive energy. Comparison with earlier work is made, and it is shown that results are markedly dependent upon the form of the repulsive potential term, the inclusion of the van der Waals term, and, indeed, the choice of coefficients of the van der Waals term. This is not the case so far as the calculated cohesive energies are concerned. The results indicate that a Born–Mayer model may be inadequate in the case of magnesium oxide, and that caution must be exercised before accepting surface energies arrived at by such calculations.

ISSN:0008-4042    

DOI:10.1139/v55-204

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

L-Sorbose has been prepared from 5-keto-D-gluconic acid.

ISSN:0008-4042    

DOI:10.1139/v55-205

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Some aspects of the mercury photosensitized decomposition of ethylene oxide at room temperature have been reinvestigated. At least two, and probably more than two, distinct primary steps occur. The previously assumed major primary formation of hydrogen by a molecular process is shown to occur to a relatively small extent only. Hydrogen atoms play an important role in the process, as well as the following radicals: CH3, CHO, CH2CHO, and C2H5, and probably to a lesser extent also CH2. The products formed are CO, H2, C2H6, a little CH2CO and C2H4, and large amounts of aldehydes. The presence of higher aldehydes has been demonstrated. While there is a general similarity to the other modes of decomposition of ethylene oxide, a unique and unambiguous solution of the complete reaction mechanism is at present not possible.

ISSN:0008-4042    

DOI:10.1139/v55-206

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The solubilities of synthetic basic calcium phosphate precipitates in carbon dioxide free aqueous systems were studied over a wide range of conditions. The pH of the suspensions and the calcium and phosphate concentrations in the solutions were determined both after precipitation and after dissolution of the solid phases. Solubility criteria applied to these measurements indicated that hydroxyapatite has a definite solubility product.

ISSN:0008-4042    

DOI:10.1139/v55-207

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

It was discovered that olefinic double bonds are readily oxidized in an aqueous solution of periodate which contains only catalytic amounts of permanganate. The data suggest that in the effective pH range of 7 to 10 the permanganate is not reduced at once beyond the manganate state and that it is regenerated from this state by periodate action. Evidence was obtained that the main course of the oxidation of an olefin of type —CH=CH— involves first permanganate oxidation to hydroxyketones which are then rapidly cleaved by periodate to products which may subsequently be oxidized by the permanganate.

ISSN:0008-4042    

DOI:10.1139/v55-208

出版商:NRC Research Press    

年代:1955

数据来源: NRC