摘要:

This study demonstrates that N-mono- and N,N-di-substituted ureas and thioureas may expediently be synthesized, in essentially theoretical yield, by reacting primary or secondary aliphatic, alicyclic, aralkyl, aromatic, and heterocyclic amines with silicon tetraisocyanate or tetraisothiocyanate, or the corresponding methyl-substituted analogues. The method fails with aromatic amines possessing bulky (e.g. phenyl, bromo), or strongly electronegative (e.g. trifluoromethyl), substituents in the 2-, or 2,6-positions of the aromatic nucleus. Data on several new substituted ureas and thioureas are reported, and improved preparative procedures for the silicon pseudohalides are described.

ISSN:0008-4042    

DOI:10.1139/v63-311

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Coordination complexes between dinitriles of dicarboxylic acids and tetrahalides of titanium, zirconium, or tin have been prepared. The analytical results and the infrared spectra indicate that on working under different experimental conditions three types of compounds are obtained: 2MX4.L—L, MX4.L—L, and MX4.2L—L where MX4is a Lewis acid and L—L a bidentate ligand. The compounds 2MX4.L—L are explained by the formation of halogen bridging between the two metal atoms. The compounds MX4.L—L are considered to be either coordination polymers or chelates of variable ring size and the compounds MX4.2L—L, ordinary addition compounds where no chelation takes place because of the mutual interaction of the two CN groups in a dinitrile of a short chain length.

ISSN:0008-4042    

DOI:10.1139/v63-312

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The β-quinol clathrates of nitrogen, carbon dioxide, methanol, and methyl cyanide decompose at temperatures well below the melting point of the host quinol lattice. The accompanying endothermal effect is broad, indicating that the decomposition occurs gradually over a considerable temperature range. The clathrate decomposition was verified by measurement of the gas evolved. The enthalpy change accompanying decomposition correlates closely with the energy of interaction of the guest molecule with the β-quinol lattice, and the decomposition of the clathrate is suggested to occur by a lattice distortion mechanism in which the size and shape of the guest molecule are important.

ISSN:0008-4042    

DOI:10.1139/v63-313

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Examination of the thermal decomposition of urea inclusion compounds has been extended to complexes of the even-numbered members of the following aliphatic series:n-alcohols,n-alkylamines,n-alkyl bromides, andn-carboxylic acids. The decomposition has been studied primarily by differential thermal analysis and an attempt made to correlate the observed decomposition temperatures and heats of decomposition with the particular guest species. The decomposition mechanism appears to involve acquisition of sufficient energy by the guest molecule to permit its diffusion from the canal, the decomposition temperature being related to the activation energy required for this diffusion process.

ISSN:0008-4042    

DOI:10.1139/v63-314

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The infrared spectra in the carbonyl-stretching region of certain arylaliphatic esters, RCOOMe, have been examined. The stretching frequencies and absorption intensities are presented and are discussed in terms of polar and α-mass effects and the occurrence of conformational isomers.

ISSN:0008-4042    

DOI:10.1139/v63-315

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The ultraviolet spectra are reported of a series of 9-alkylphenanthrenes. The bathochromic shifts relative to phenanthrene of the longest-wavelength (α) band are not explicable in terms of hyperconjugation. It is suggested that the band envelope is influenced by the rotameric forms of the alkyl substituents.

ISSN:0008-4042    

DOI:10.1139/v63-316

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The heartwood of jack pine was analyzed by various chromatographic techniques and countercurrent distribution. The major components were found to be isopimaric, abietic, dehydroabietic, and neoabietic acids, as well as glycerides of oleic, linoleic, and linolenic acids. Smaller amounts of pimaric, sandaracopimaric, myristic, palmitic, stearic, palmitoleic, and four unidentified acids were recorded, as well as fatty acid esters of β-sitosterol, α-terpineol, and four unidentified volatile alcohols. Of the phenols, pinocembrin, pinobanksin, and pinosylvin monomethyl ether predominated. Pinosylvin was isolated and several minor constituents including lignan-like compounds were detected in the acetone extract. The methanol extract was composed mainly of polymeric lignan-like fractions. From one of these a trimer, C60H66O24, m.p. 186–188 °C,αd + 3.2°, was isolated. The small amount of steam-volatile material consisted mainly of α- and β-pinene, benzoic acid, and α-terpineol. Traces of methyl benzoate, camphene, limonene, β-phellandrene,cis-p-menthan-8-ol, and nine unidentified trace components were recorded.

ISSN:0008-4042    

DOI:10.1139/v63-317

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

H2O–D2O mixtures containing 0.1–1 NH2SO4were irradiated by 200-kv X rays. The molecular isotope effect,, was determined from experiments on KBr solutions. The atomic isotope effect,, was determined from experiments on ethanol solutions. At 96% D2O, αA = 3.7 ± 0.5 and αM = 4.0 ± 0.2. The isotope effects are discussed in connection with the radiation-chemical reaction H3O+ + eH2O → H + 2H2O. The connection between the atomic and molecular hydrogen is discussed. It is concluded that the relation between the observed atomic and molecular isotope effects isnotcontrary to a hydrogen atom recombination reaction leading to the molecular product. Isotope effects due to the oxidation of Fe+2ions by hydrogen atoms in acid solutions were measured and the mechanism of this reaction is discussed.

ISSN:0008-4042    

DOI:10.1139/v63-318

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

3α-Bromocholestan-2β-ylp-toluenesulphonate on heating in solution rearranges to an equilibrium mixture in which the diequatorial isomer, 2α-bromocholestan-3β-ylp-toluenesulphonate, predominates. 2β-Bromocholestan-3α-ylp-toluenesulphonate and the corresponding diaxial benzenesulphonate andp-nitrobenzenesulphonate rearrange analogously. These are the first examples of the diaxial → diequatorial rearrangement with sulphonic esters. Replacement of the para methyl group of 2β-bromocholestan-3α-ylp-toluenesulphonate by more electrophilic substituents is accompanied by an increase in the rate of rearrangement. It is concluded that in the transition state the bromine atom is positively charged and the sulphonate group negatively charged relative to the starting material.

ISSN:0008-4042    

DOI:10.1139/v63-319

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Radiochemical techniques have been used to determine absolute excitation functions for 17 nuclides formed as spallation products from the irradiation of vanadium by protons of energy up to 84 Mev. The shape of the excitation functions and classical threshold calculations showed evidence of contribution of heavy-particle emission in the reactions of the type (p,3pxn), (p,5pxn), and (p,7pxn). The Barr method for analysis of the cross-section distribution was modified and applied at 60 and 80 Mev bombarding energies. The experimentally measured cross sections for 16 nuclides at 60 and 80 Mev bombarding energies were fitted to the four-parameter Rudstam equation σ (A,Z) = exp [PA−Q−R(Z−SA)2]. Comparison of the results obtained at 8 Mev bombarding energy with the predictions of the weak and strong absorption models showed better agreement with the predictions obtained by using the surface absorption Fernbach–Bjorklund potential.

ISSN:0008-4042    

DOI:10.1139/v63-320

出版商:NRC Research Press    

年代:1963

数据来源: NRC