摘要:

The results of highly precise measurements of ultrasonic velocity in mixtures of deuterium oxide with water by Kiyoharaet al. were used to calculate and discuss the excess velocity of sound in this system.

ISSN:0008-4042    

DOI:10.1139/v79-374

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The calculations of excess sound velocities in D2O–H2O mixtures by Ernst and Glinski are discussed and new results are presented.

ISSN:0008-4042    

DOI:10.1139/v79-375

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The formation of the molecular complexes of some phenylfurans with TCNE has been investigated by spectroscopic methods. The formation constants were determined by graphical and iterative procedures and some thermodynamic parameters were calculated. The formed molecular complexes were π ones. Diphenylfuran proved to be a much stronger electron donor than phenylfuran and the latter stronger than furan. Results at hand suggest that the donors investigated assume an all-planar conformation.

ISSN:0008-4042    

DOI:10.1139/v79-376

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The regiospecific 1,3-dipolarcycloaddition reaction of 1,2-dihydropyridines1with organic azides2afford 2,7-diazabicyclo[4.1.0]hept-4-enes4, whereas solutions of1also containing lithium hydroxide give predominately4along with the diazo product6. In contrast, the dimeric product7was obtained from the reaction of1awith hydrazoic acid. Catalytic hydrogenation of4gives rise to a tautomeric mixture of9and10; when R2is methanesulfonyl orp-aminobenzenesulfonyl only9was obtained. Treatment of4with neutral alumina gives rise to the 1,2,5,6-tetrahydropyridylidenes8which are likewise reduced to a mixture of9and10or9.

ISSN:0008-4042    

DOI:10.1139/v79-377

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Rate constants measured with the flowing afterglow technique at 297 ± 2 K are reported for the protonation of CH2O by H3+, N2H+, CH5+, HCO+, C2H5+, H3O+, H3S+, and HCNH+and for the subsequent deprotonation by NH3. The rate constants are compared with predictions of various theories for ion–molecule collisions. The protonation was observed to proceed in the absence of competing channels and further decomposition and is discussed in terms of the energetics of the two sites of protonation and the energetics and mechanism of H2elimination. The rate measurements provide evidence for the room-temperature conversion of the adduct C2H3+•H2to the more stable isomer derived from the direct protonation of C2H4.

ISSN:0008-4042    

DOI:10.1139/v79-378

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The influence of 2,4- and 2,6-dimethylphenol, 2,3,6- and 2,4,6-trimethylphenol, 2,3,4,6- and 2,3,5,6-tetramethylphenol, 2,6-diisopropylphenol, 2-tert-butyl-4-methylphenol and 2,4-di-tert-butylphenol on the stannic chloride initiated polymerization of isobutene has been investigated. At −78.5 °C and with 0.185 Mstannic chloride, these phenols act as coinitiators. Rates of polymerizaiton reach maximum values at phenol concentrations which depend greatly on the number and positions of alkyl substituents; molecular weights decrease continuously with phenol concentration. Phenols without 4-substituents are incorporated in polyisobutenes as end groups and those with 4-substituents give rise largely to olefinic end groups. Termination of polymerization occurs mainly by attack at a free 4-position or at the OH group. The initialtert-butyl carbenium ion is more readily terminated by 2,6-di-tert-butylphenol than the polymer carbenium ion.The rate and molecular weight results are interpreted in terms of a simplified reaction scheme in which termination occurs spontaneously or by reaction with uncomplexed phenol. Rate constants for termination by methyl-substituted phenols are of the order of one tenth of the propagation rate constant while those for 2-tert-butyl-4-alkylphenols are about one hundredth of the propagation rate constant.

ISSN:0008-4042    

DOI:10.1139/v79-379

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Using difference spectroscopy,13C spin–lattice relaxation measurements on 40% egg phosphatidylcholine multilamellar liposomes (containing 25 mol% cholesteryl palmitate)–60% D2O indicate the ester contributes negligibly to the microviscosity of the acyl chains in the bilayers.At 37 °C, spin–spin and spin–lattice relaxation measurements have been obtained for 25 mol% cholesteryl linoleate in both egg phosphatidylcholine and dipalmitoyl phosphatidylcholine multilayers and indicate: (a)T1values of the linoleate ester chain are 0.5 times those of the lecithin chain carbons, and (b)T2* = 16 ± 6 ms foralldiscernable linoleate carbons. At 52 °C, cholesteryl ring carbons C5 and C6 yieldT2* values of 23 and 20 ms, respectively. These studies suggest the esters reside in an environment whose "fluidity" approaches that found in very low density lipoprotein (VLDL).

ISSN:0008-4042    

DOI:10.1139/v79-380

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Reaction of 10H-pyrido[3,2-b][1,4]benzothiazines1possessing a 10-methyl1f, 10-(3-dimethylaminopropyl)1b, or 10-(2-dimethylaminopropyl)1csubstituent, withn-butyllithium and methyl chloroformate or diethyl chlorophosphate affords predominantly 1,2-dihydropyridines11and the 4-substituted derivatives12. The 1,7-disubstituted product15bwas obtained from reaction of the 10-methyl compound1fwithp-fluorobenzoyl chloride. On the other hand, treatment of the 10-methyl analog1fwith trifluoromethanesulfonyl chloride gave the unexpected 4-chloro derivative12cand13cwhich probably arises from the 1-trifluoromethanesulfonyl-1,2-dihydropyridine11cvia elimination of trifluoromethanesulfonic (sulfinic) acid. The N-10 dealkylated product1awas obtained from reaction of the 10-(1-methyl-2-dimethylaminoethyl) analog1gwithn-butyllithium and methyl chloroformate, whereas a similar reaction employing the 10-(2-dimethylaminoethyl) derivative1hgave rise to theN-methoxycarbonyl derivative18. On the other hand, reaction of1hwithn-butyllithium alone gave the N-10n-hexyl product19. Mechanisms for the formation of1a,11, 12, 13, 15, 16, and19are described.

ISSN:0008-4042    

DOI:10.1139/v79-381

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Crystals of Ni(II) bis(morpholine-N-carbodithioate) are monoclinic,a = 4.291(1),b = 20.584(2),c = 8.365(1) Å, β = 97.39(2)°,Z = 2, space groupP21/n. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures toR = 0.036 andRw = 0.044 for 1800 reflections withI ≥ 3σ(I). The crystal structure consists of discrete molecules having approximateC2hand exact (crystallographic)Cisymmetry. The nickel atom is coordinated to four sulphur atoms in a planar arrangement with Ni—S = 2.2122(7) and 2.2134(6) Å and S—Ni—S = 79.16(2) and 100.84(2)°.The electron paramagnetic resonance spectra of63Cu(II) bis(morpholine-N-carbodithioate) and63Cu(II) bis(pyrrolidine-N-carbodithioate) doped in the respective Ni(II) analogues have been recorded at room temperature. The spin Hamiltonian parameters obtained from an analysis of the spectra of the polycrystalline samples have been used to investigate the bonding in these complexes. The results are compared to previous studies in carbodithioates.

ISSN:0008-4042    

DOI:10.1139/v79-382

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Excess volumes,VE, of binary mixtures of β-picoline and γ-picoline with ethanol,n-propanol, andn-butanol have been measured as a function of composition at 308.15 K by a dilatometric method. TheVEdata are negative for all the mixtures studied here and suggest that the stronginteractions outweigh those due to the breaking of thebonds.

ISSN:0008-4042    

DOI:10.1139/v79-383

出版商:NRC Research Press    

年代:1979

数据来源: NRC