摘要:

The near-ultraviolet absorption spectra of polyphenyl derivatives of the IVband Vbelements have been studied in detail. In the case of the triphenyl derivatives of the Vbelements, the unsharedp-electrons on the central atoms interact strongly with the π-orbitals of the benzene rings. When the central atoms do not possess unshared electrons as in the case of the derivatives of the IVband the pentavalent Vbelements, there appears to be no such resonance interaction. The Hammett reactivity constants of the para- and meta-trityl, triphenylsilyl, and triphenylgermanyl groups are estimated to be close to zero. However, the reactivity constant of the triphenylsilyl group in the para position of phenol is estimated to be about 0.30. The infrared spectra of the phenyl derivatives of the IVband Vbelements show smooth trends due to mass effects of the central atoms, in the C=C skeletal, C—H out-of-plane, and other vibrations. The absorption frequencies which are assigned to the phosphorus-phenyl and silicon–phenyl bonds in the literature do not appear to be unique for these linkages.

ISSN:0008-4042    

DOI:10.1139/v61-021

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Mixtures of chlorobenzene and chlorobenzene-2-2H have been subjected to partial amination by sodamide in liquid ammonia and both the unreacted starting material and the product aniline have been analyzed for deuterium. Deuterium in the aniline is distributed approximately equally between the ortho and meta positions. The results give strong support to the mechanism proposed by Roberts and co-workers in which the slow step is the formation of an intermediate, such as benzyne, which is symmetrical with respect to carbon atoms 1 and 2.

ISSN:0008-4042    

DOI:10.1139/v61-022

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The polysaccharide from gum asafoetida containsD-galactose,L-arabinose,L-rhamnose, 4-O-methyl-D-glucuronic acid, andD-glucuronic acid. It is a highly branched polymer which contains a backbone ofD-galactopyranose residues which are very probably mainly 1,3-β-linked.The side chains consist of residues ofL-arabinofuranose,D-galactopyranose,D-glucuronic acid, and its 4-O-methyl ether.

ISSN:0008-4042    

DOI:10.1139/v61-023

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The principles of capillary viscometry are reviewed, and design criteria for capillary viscometers to be used with non-Newtonian liquids are discussed. A description is given of a new type of variable-shear capillary viscometer—a modification of the Ubbelohde suspended-level viscometer—designed for measurements in the low-shear range. The instrument is rugged, convenient, and precise, and makes possible measurements at free fall over a 10-fold range of shear stress (or shear rate), a range that can easily be extended by use of two or more suitably modified instruments or by the application of external pressure. Experimental evidence is presented to show that proper choice of the dimensions of the instrument eliminates or minimizes most of the "effects" that limit the precision of measurements of relative viscosity (and related functions) of high polymer solutions in the range of low shear stresses.

ISSN:0008-4042    

DOI:10.1139/v61-024

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The analyses of theABX,A2X2, andABXYtypes of spectra are discussed in detail under the conditions for which the observed spectra give less than the theoretical number of transitions. These conditions for which an observed spectrum is deceptively simple are derived from the general analyses, and experimental examples of such spectra are given.

ISSN:0008-4042    

DOI:10.1139/v61-025

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The paper chromatographic behavior of several 5,6-dihydroxyindoles has been studied. The colors given by nine dihydroxyindoles with 16 chromogenic reagents are reported. TheRfvalues of this group of compounds on Whatman No.1paper with 2% acetic acid in water orn-butanol/acetic acid/water (6:1:2) as running solvents have been determined. The 5,6-dihydroxyindoles can be chromatographed satisfactorily using Zaffaroni-type systems (i.e. formamide-treated paper and non-polar running solvents). SatisfactoryRfvalues can also be obtained for the 5,6-diacetoxyindoles on formamide-treated paper using a suitable non-polar mobile phase. The preparations of several new 5,6-dihydroxyindoles and 5,6-diacetoxyindoles are described and improved procedures for the syntheses of some known members of these groups are reported.

ISSN:0008-4042    

DOI:10.1139/v61-026

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

A compilation of the S—O symmetric and asymmetric stretching frequencies is given for a large number of compounds containing an —SO2— group. It is shown that a linear relationship betweenis valid for a large number of sulphuryl and polysulphuryl compounds and that the actual frequencies depend in a systematic manner on the electronegativities of the attached groups. These relationships have proved very useful in assigning and in some cases reassigning the S—O bands in the infrared and Raman spectra of a number of sulphuryl compounds. It is pointed out that there is a relationship between the SO2frequencies of some sulphonic acids and their acid strengths.The calculation of values for group electronegativities from the vibration frequencies of the P=O and SO2groups is discussed.

ISSN:0008-4042    

DOI:10.1139/v61-027

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v61-028

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v61-029

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v61-030

出版商:NRC Research Press    

年代:1961

数据来源: NRC