摘要:

The polysaccharide was obtained by polymerization ofD-xylose at 140 °C in the presence of phosphorous acid. Complete hydrolysis of the xylan followed by bromine oxidation showed that the synthetic polymer contained only xylose. Periodate oxidation resulted in formation of a considerable quantity of formaldehyde, the origin of which is not known. Periodate oxidation of borohydride-reduced xylan gave additional formaldehyde and, from this, the average D. P. of the polymer was estimated to be about 55. Complete hydrolysis of the polyalcohol gave ethylene glycol, glycerol, and xylose in a ratio of 2:9:1. Partial hydrolysis gave ethylene glycol, glycerol, and at least seven non-reducing components. Hydrolysis of the fully methylated xylan gave tri-, di-, mono-methyl xyloses and xylose in a 32:32:18:5 ratio, and a carbonyl band was evident in the infrared spectrum of the hydrolyzate. No such band was evident in the hydrolyzate of the unsubstituted xylan. The xylan is highly branched and contains someD-xylofuranose units.

ISSN:0008-4042    

DOI:10.1139/v62-224

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

It has been shown that the geminal and vicinal coupling constants are of opposite sign in α,β-diphenylpropionic acid and its methyl ester. The significance of the results is discussed.

ISSN:0008-4042    

DOI:10.1139/v62-225

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Complex tellurates of manganese and cobalt have been prepared by oxidizing mixtures of manganous or cobaltous sulphate with potassium (or sodium) tellurate by means of an alkaline hypochlorite solution. Cobalt gives K3H6Co(TeO6)2•2H2O as a dark green powder. The formula was confirmed by its oxidation equivalent with ferrous sulphate, by its displacement of chloride ions from an anion exchange resin, and by its magnetic susceptibility (−154 × 10−6 e. m. u./g-mol). The behavior of the compound on acidification is reported. Manganese gives K6H8Mn(TeO6)3•5H2O and Na7H7Mn(TeO6)3•5H2O as dark red crystals. The formula was confirmed as for the cobalt complex: its magnetic moment is 3.30 Bohr magnetons, which is reasonable for Mn(IV). The acid–base properties of the compound were examined. The ion is not very stable in solution, as shown by changes in its absorption spectrum; measurements of this gave evidence for the nature of the decomposition, and the equilibrium constant for this reaction. The main reaction isfor whichK = 4 × 10−5(g-mol/I.)2at 25 °C.

ISSN:0008-4042    

DOI:10.1139/v62-226

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

It has been established (D. W. Colcleugh and W. F. Graydon. J. Phys. Chem. In press) that hydrogen peroxide is produced during the dissolution of polycrystalline copper in dilute aqueous solutions. The hydrogen peroxide formed during the dissolution further attacked the metal, producing additional cupric copper in solution. The kinetics of this heterogeneous reaction was investigated in aerated sulphuric acid solutions. Under these experimental conditions the ratio of the increase in concentration of cupric ion to the decrease in concentration of hydrogen peroxide was constant at the value of 2. In deaerated sulphuric acid this stoichiometric ratio was constant at the value of 1 under similar experimental conditions.Rate equations for the formation of cupric ion in solution and for the decomposition of hydrogen peroxide in the solution were determined as a function of sample area, corroding solution volume, temperature, hydronium ion concentration, cupric ion concentration, and hydrogen peroxide concentration.A reaction mechanism was suggested to describe the empirical rate equations and the stoichiometry obtained experimentally.

ISSN:0008-4042    

DOI:10.1139/v62-227

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

An investigation has been made of the polymerization of 1-butene by TiCl3–Al(i-Bu)3catalysts in heptane solution at 40 °C. The polymerization curve has two segments covering initial and steady-state periods at which the rate increases several fold. The change in rate, which occurs after the formation of a constant amount of polymer for a given concentration of TiCl3, is interpreted as an increase in surface area due to breakdown of the catalyst particles. For the steady-state period, it has been shown that the rate of polymerization is proportional to the monomer and titanium trichloride concentrations and approaches a constant value as the aluminum triisobutyl concentration increases.The intrinsic viscosity of the bulk polymer and the crystallinity, as determined by infrared analysis, were found to be essentially independent of the concentrations of the catalyst components and the extent of polymerization.The results are considered in terms of current theories on the mechanism of heterogeneous polymerization.

ISSN:0008-4042    

DOI:10.1139/v62-228

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The chemical shift of the methyl protons relative to the methylenic protons of an ethyl group attached to a basic center increases with the acidity of the medium. This increase may be attributed to two effects: over a relatively narrow range of acidity function (H0) values, to protonation of the basic center; over the completeH0range investigated, to a general solvent effect, which may be due to changing strengths of hydrogen bonds between the basic center or its conjugate acid and solvent water molecules. Protonation constantsof −1.1 for propionamide and −6.9 for propionic acid have been calculated, in good agreement with values obtained by the ultraviolet spectrophotometric method; the constants calculated for diethyl ether (−6.2) and ethanol (−4.8) are much less certain, because of the greater magnitude of the solvent effect with these compounds.

ISSN:0008-4042    

DOI:10.1139/v62-229

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The hydrogen isotope effect in the pyrolysis of ethyl-1,1,2,2-d4chloride has been investigated in the temperature range 758–989 °C, yielding the relative rate constant expressionwherekHandkDare the rate constants for the production of C2D4(and HCl) and of C2D3H (and DCl) per β-deuterium atom respectively.The isotope effect is pressure dependent, its value increasing with decreasing pressure. The pressure effect in ethyl chloride has also been studied, and a qualitative explanation is given for the pressure dependence of intermolecular and intramolecular isotope effects.The data are compared with the isotope effects in ethyl-d4bromide and ethyl-d4acetate, and the conclusion is reached that the evidence supports a four-centered transition-state complex in the case of the halides.

ISSN:0008-4042    

DOI:10.1139/v62-230

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The relative rate constant expression has been obtained for the decomposition of ethyl-1,1,2,2-d4bromide under inhibiting conditions in the temperature range 697.6 to 999.1 °K,The pressure dependence of the isotope effect has been investigated both with and without inhibitor, and in each case it has been shown that the isotope effect increases with decreasing pressure.The relative rate constant expression for the ethyl-h5, ethyl-d5bromide comparison was also obtained in the temperature range 730.9 to 964.8 °K,The isotope effect is again pressure dependent, falling to lower values as the pressure is decreased.The data are used to demonstrate that the inhibited decomposition of ethyl bromide is primarily a molecular process, and that the rate-controlling step involves a carbon–hydrogen bond break.A side reaction that produces small amounts of ethane has been observed.

ISSN:0008-4042    

DOI:10.1139/v62-231

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Three related diterpenoid quinones, royleanone, 9-acetoxyroyleanone, and 9-dehydroroyleanone, have been isolated from the roots ofInularoyleanaD. C. These have been assigned structures on the basis of degradation studies and the synthesis of royleanone from ferruginol.

ISSN:0008-4042    

DOI:10.1139/v62-232

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The preparation of somep-(ω′-dimethylaminoalkyl)- andp-(ω′-dimethylaminoalkoxy)-2-oximinoacetophenones and their methiodides is described.No general method was found for synthesis of short-chain (C0, C1, C2)p-(ω′-dimethylaminoalkyl)-2-oximinoacetophenones. The longer-chain compounds (C3, C4) were prepared by a method which would appear to be general. ω-Phenyl-1-haloalkanes undergo Friedel–Crafts acylation to yieldp-(ω′-haloalkyl)-acetophenones. These were converted to the dimethylamino compounds, which, subsequently, yielded 2-oximinoacetophenones. No method of preparation ofp-(2′-dimethylaminoethyl)-2-oximinoacetophenone was found.Synthesis ofp-(ω′-dimethylaminoalkoxy)-2-oximinoacetophenones was accomplished using mixed α,ω-dihaloalkanes andp-hydroxyacetophenone. Thep-(ω′-haloalkoxy)-acetophenones from these reactants were first converted to oximes and then to the dimethylamino compounds. Syntheses ofp-(ω′-dimethylamino-ethoxy, -propoxy, -butoxy, and -pentoxy)-2-oximinoacetophenones were achieved. That ofp-(dimethylaminomethoxy)-2-oximinoacetophenone was unsuccessful.

ISSN:0008-4042    

DOI:10.1139/v62-233

出版商:NRC Research Press    

年代:1962

数据来源: NRC