摘要:

The vapor–liquid equilibria of the 4 binary systems formed by mixing methanol withn-butanol, isobutanol,sec-butanol, andtert-butanol were investigated at 25 °C in a dynamic still with circulation. The results were used to calculate the molar excess Gibbs free energies. For the three systems containing isobutanol,sec-butanol, ortert-butanol, molar excess enthalpies and volumes were also determined (mainly at 25 °C) by direct calorimetric and dilatometric techniques. The behavior of the excess properties is discussed with reference to differences in the hydrogen bonding and in the shapes of the component molecules.

ISSN:0008-4042    

DOI:10.1139/v70-417

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

In deaerated aqueous perchloric acid solution TI(III) is reduced and 2-propanol oxidized to acetone in essentially equivalent yields by a γ-ray induced chain reaction. The yields increase linearly with increasing alcohol concentration in the range (1–8) × 10−2 M, are independent of TI(III) concentration in the range (1–4) × 10−3 Mand vary inversely with the square root of the dose rate over the range 1.6 × 1017to 1.8 × 1019 eV l−1s−1. A mechanism is proposed to account for the observed stoichiometry and kinetic parameters.The same mechanism is found to apply to the reduction of TI(III) by methanol and ethanol.t-Butyl alcohol gives a much lower yield of TI(III) reduction and alcohol fragmentation products: acetone, methane, and ethane.

ISSN:0008-4042    

DOI:10.1139/v70-418

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Experimental conditions using a variety of pHbuffers have been established to permit the rapid, accurate determination of periodate and formaldehyde by polarography. The application of these analyses to quantitative studies in the oxidation of carbohydrates was illustrated and the lower limit of detection presently available found to be equivalent to 0.04 μmole carbohydrate.

ISSN:0008-4042    

DOI:10.1139/v70-419

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The reaction of BF3with B2O3in a molecular flow reactor has been studied with a mass spectrometer. Over the temperature range 930–1300 K the reaction has been found to produce B2OF4with the stoichiometryFrom the temperature dependence of the equilibrium constant the enthalpy change for this reaction was determined to be 18.5 ± 3 kcal/mole and ΔHf0(B2OF4) calculated to be −454 ± 2 kcal/mole at 1100 K.

ISSN:0008-4042    

DOI:10.1139/v70-420

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Triphenylbismuth(V) acid derivatives of the type, Ph3BiX2, where X = halide, nitrate, cyanate, acetate, haloacetate, or cyanoacetate have been prepared. Infrared spectra (4000 to 200 cm−1region), electrical conductances, and molecular weights of these compounds have been studied to elucidate their structural features and chemical constitution. The molecular weight and conductance data show that these compounds behave as molecular species in benzene or nitromethane. The infrared spectroscopic results also indicate non-ionic five-coordinate structures. Bi—X stretching frequencies have been assigned for the difluoride, dichloride, dinitrate, dicyanate, and diacetate. These frequencies occur in the region 410–240 cm−1.

ISSN:0008-4042    

DOI:10.1139/v70-421

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

First-order rate constants for the solvolysis of benzyl chloride in a series of aqueous acetone and aqueous dimethylsulfoxide (DMSO) mixtures at 50.100 °C and at various pressures in the range 1–4083 atm are reported. Volume of activation, calculated from the rate/pressure data, is found to exhibit extremum behavior with varying solvent composition in both solvent systems. The activation volumes are dissected into their initial state and transition state contributions by determining the "instantaneous" volumes of solution of benzyl chloride in the solvent systems. The contributions of both the initial state and the transition state to the behavior of the activation volume as a function of solvent composition are discussed.

ISSN:0008-4042    

DOI:10.1139/v70-422

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Lipopolysaccharide (LPS) prepared fromEscherichiacoli086:Kneg., in 5.5% yield containedD-galactose,D-glucose,L-fucose,L-glycero-D-manno-heptose,D-glucosamine,D-galactosamine, 2-keto-3-deoxy-octulosonic acid (KDO) and lipid A. The molecule appeared to be homogeneous as tested by free boundary electrophoresis, ultracentrifugation, and immunodiffusion against ′O′ specificE.coliantiserum. Methylation studies of the LPS and also of the degraded polysaccharides obtained by partial acid hydrolysis showed that the molecule was highly branched. Sixty percent of theD-galactose units were non-reducing terminal groups, the remainder were linked (1 → 3) and (1 → 2) and 3-O-β-D-galactopyranosyl-D-galactose was identified as a product of mild acid hydrolysis of the parent LPS. Fucose occurred in the polysaccharide as (1 → 4) linked units. Methylation results showed that theD-glucose units were linked (1 → 3) and (1 → 4). Partial acid hydrolysis yielded cellobiose, cellotriose, and laminaribiose, showing that the glucose units formed a glucan chain within the polysaccharide and that the glucosidic linkages were in the β-D-configuration. Approximately one half of theL-glycero-D-manno-heptose units occurred as non-reducing end groups, the other half were linked at C-3 and either one of C-6 or C-7. One half of theD-galactosamine units was linked (1 → 3) with the remainder occurring as double branch points.D-Glucosamine residues occurred exclusively in the lipid A moiety in a (1 → 4) linked core structure.

ISSN:0008-4042    

DOI:10.1139/v70-423

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The synthesis of the tetrapeptide,N-t-butoxycarbonyl-ϵ-N-carbobenzoxy-L-lysylglycyl-ϵ-N-carbobenzoxy-L-lysylglycine 4-(methylthio)phenyl ester is described. The utility of this protective ester is shown by its easy conversion to the protected tetrapeptide 4-(methylsulfonyl)phenyl activated ester without decomposition. Removal of theN-butoxycarbonyl protecting group afforded the polymerizing unit, ϵ-N-carbobenzoxy-L-lysylglycyl-ϵ-N-carbobenzoxy-L-lysylglycine 4-(methylsulfonyl)phenyl ester. Polymerization of this material on the partially blocked monomer glycine-1-C14ethyl ester hydrochloride, at a relatively high dilution, gave poly-(ϵ-N-carbobenzoxyl-L-lysylglycyl)glycine-1-C14ethyl ester. The carbobenzoxy protective groups were removed to give the title compound.

ISSN:0008-4042    

DOI:10.1139/v70-424

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

4-Cyano-3-hydroxy-2-oxo-3-pyrrolines are strongly acidic and form salts rather than enamines with strongly basic amines. We have revised the structures proposed for some of their derivatives and report the first synthesis of the parent compound1(R = H) and other new related pyrrolines.

ISSN:0008-4042    

DOI:10.1139/v70-425

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The incorporation of 4-14C-mevalonate into dendrobine, the major alkaloid ofDendrobiumnobile(Orchidaceae), is consistent with a biosynthesis involving successive intermediates withtrans-cisfarnesol, germacrane, and cadalane skeletons.

ISSN:0008-4042    

DOI:10.1139/v70-426

出版商:NRC Research Press    

年代:1970

数据来源: NRC