Showing papers in "Canadian Journal of Chemistry in 1966"
TL;DR: In this article, the infrared spectrum of HDO at low concentrations in H2O and in D2O was studied between 0° and 130° by a double-beam technique.
Abstract: The infrared spectrum of HDO at low concentrations in H2O and in D2O was studied between 0° and 130° by a double-beam technique. Each of the three fundamentals of HDO shows nearly Gaussian contours...
316 citations
TL;DR: The proton magnetic resonance spectra of D-xylose, D-lyxose and D-arabinose were determined at 100 Mcp.s. in deuterium oxide as discussed by the authors.
Abstract: The proton magnetic resonance spectra of D-xylose, D-lyxose, D-arabinose, D-ribose, D-glucose, D-mannose, and D-galactose were determined at 100 Mc.p.s. in deuterium oxide. The chemical shifts and ...
311 citations
TL;DR: Azotobactervinelandii produces a partly acetylated exocellular polysaccharide which consists mainly of D-mannuronic Acid units and a small proportion of L-guluronic acid units which resembles alginic acid.
Abstract: Azotobactervinelandii produces a partly acetylated exocellular polysaccharide which consists mainly of D-mannuronic acid units and a small proportion of L-guluronic acid units. It resembles alginic...
277 citations
TL;DR: In this paper, a comparison of seven numerical methods of fitting infrared absorption band envelopes with analytical functions using nonlinear least squares approximations is made, including Gauss and Cauchy (Lorentz...
Abstract: A comparison has been made of seven numerical methods of fitting infrared absorption band envelopes with analytical functions using nonlinear least squares approximations. Gauss and Cauchy (Lorentz...
233 citations
TL;DR: The thicknesses of oxide films formed in aqueous borate solutions were obtained by the spectrophotometric method after developing the interference colors by evaporating a very thin film of gold or...
Abstract: The thicknesses of oxide films formed in aqueous borate solutions were obtained by the spectrophotometric method after developing the interference colors by evaporating a very thin film of gold or ...
152 citations
TL;DR: In this article, a linear relationship exists between the logarithms of equilibrium quotient, [SH+]/[S][H+], of diverse bases as they vary with acid concentration in moderately concentrated mineral acids.
Abstract: Linear relationships exist between the logarithms of equilibrium quotients, [SH+]/[S][H+], of diverse bases as they vary with acid concentration in moderately concentrated mineral acids. For purposes of formulating these linear free energy relationships in standard form, the equilibrium quotient for protonation of a hypothetical aromatic primary amine of pKa zero has been chosen as horizontal coordinate; this is given by (−H0 − log [H+]). Log ([SH+]/[S]) + H0 is plotted against (H0 + log [H+]). The slope, of the linear plot is a parameter which characterizes the response of the equilibrium quotient to changing acid concentration. The intercept represents the thermodynamic pKa of the base. This constitutes a general method for estimating the pKa of any base which undergoes protonation in moderately concentrated mineral acid, with reference to the single acidity function, H0. For bases of diverse type, pK's estimated by this method are in good agreement with those estimated by the acidity function method. U...
127 citations
125 citations
117 citations
TL;DR: In this article, the dissociation of surface hydroxyl groups of crystalline SiO2, ZrO2 and ThO2 was studied as a function of pHs at different ionic strengths of KNO3.
Abstract: The dissociation of surface hydroxyl groups of crystalline SiO2, ZrO2, and ThO2, in aqueous suspensions, has been studied as a function of pHs at different ionic strengths of KNO3. The surface grou...
114 citations
TL;DR: In this paper, the effects of substitution on the aromatic and methoxyl carbon shieldings were investigated using the 13C nuclear magnetic resonance spectra of a series of 40 substituted anisoles.
Abstract: The 13C nuclear magnetic resonance spectra of a series of 40 substituted anisoles have been obtained to investigate the effects of substitution on the aromatic and methoxyl carbon shieldings. This work extends our studies on the variations of chemical shifts of carbon nuclei in side chains of aryl derivatives. The question of steric hindrance to conjugative interaction of a methoxyl group with an aromatic ring is considered on the basis of the present results. Evidence of a steric effect in compounds in which both ortho positions are substituted is presented.
110 citations
TL;DR: In this paper, total cross sections for ionization by 75 V electrons have been measured for a wide range of molecules and the results were in agreement with the cross sections reported by Lampe et al. rat...
Abstract: Total cross sections for ionization by 75 V electrons have been measured for a wide range of molecules. On the whole the results are in agreement with the cross sections reported by Lampe etal. rat...
TL;DR: In this article, the infrared spectra of metal-free phthalocyanine, chlorinated and unchlorinated copper phthalocaline, and three new metal derivatives of phTHC: MoPc, Na2Pc and AlOH-Pc have been recorded.
Abstract: Infrared spectra of metal-free phthalocyanine, chlorinated and unchlorinated copper phthalocyanines, and three new metal derivatives of phthalocyanine: MoPc, Na2Pc, and AlOH—Pc (Pc = C32H16N8), have been recorded Assignments have been suggested for many of the peaks in the infrared spectra of the phthalocyanines
TL;DR: The extracellular fibers attached to the diatom Thalassiosirafluviatilis have been shown to be pure β-(1'→'4)-linked 2-acetamido-2-deoxy-D-glucan as discussed by the authors.
Abstract: The extracellular fibers attached to the diatom Thalassiosirafluviatilis have been shown to be pure β-(1 → 4)-linked 2-acetamido-2-deoxy-D-glucan. This polysaccharide was given the systematic trivi...
TL;DR: In this article, magnetic resonance properties of hydroxyl protons are described for a variety of sugars and derivatives in dimethyl sulfoxide, particularly for differentiating between certain types of interconvertible molecular species.
Abstract: Some magnetic resonance properties of hydroxyl protons are described for a variety of sugars and derivatives in dimethyl sulfoxide. Spectral information of this kind is shown to be useful, particularly for differentiating between certain types of interconvertible molecular species. For example, a reducing sugar may be characterized as pyranose or furanose depending upon whether it exhibits a resonance signal that can be ascribed to OH-4 or OH-5, respectively. According to the data obtained, α-D-glucose, α-D-xylose, β-D-arabinose, α-D-lyxose, and α- and β-D-ribose are pyranoses when freshly dissolved, whereas the 2,3-carbonate of D-mannose or D-lyxose is in a furanose form. Selective deuteration and spin decoupling were of primary importance in making some of the spectral assignments.Although arabinose, ribose, and galactose exist partly as furanoses in mutarotated aqueous solutions, their tendency to adopt the structure of the five-membered ring is much greater in dimethyl sulfoxide. Such variability may ...
TL;DR: Sugars possessing the arabino (2,3,4-trans,cis) configuration exist as furanoses to a greater extent in dimethyl sulfoxide than in water.
Abstract: Sugars possessing the arabino (2,3,4-trans,cis) configuration exist as furanoses to a greater extent in dimethyl sulfoxide than in water. Their 2,3-di-O-methyl derivatives show an even stronger pre...
TL;DR: In this article, the authors investigated the desulfurization of thiophene over five molybdenum disulfide catalysts, an alumina-supported cobalt-molybdate, and a chromia catalyst.
Abstract: The hydrodesulfurization of thiophene over five molybdenum disulfide catalysts, an alumina-supported cobalt molybdate, and a chromia catalyst has been investigated. Comparisons on the basis of equal surface areas showed that desulfurization activity did not vary a great deal. It was established mainly by working at very low conversion levels that 1,3-butadiene was a product over all these catalysts, and that a mixture of butadiene, the three n-butenes, and n-butane constituted the actual primary reaction product. The reaction rate is strongly dependent on conversion, probably as the result of small quantities of product H2S, the rate decreasing by a factor of 100 in going from 0.01% to 5% conversion in a typical flow experiment. A strong enhancement of the rate over MoS2 was noted in the presence of oxygen.
TL;DR: Hydrogen bonding between pairs of derivatives of the base constituents of nucleic acids and their analogues has been studied in chloroform solution by infrared spectrophotometry and indicates that these complexes have a structure similar to that of the complexes formed between the corresponding pairs of bases in the naturally occurring desoxyribonucleic acid chain.
Abstract: Hydrogen bonding between pairs of derivatives of the base constituents of nucleic acids and their analogues has been studied in chloroform solution by infrared spectrophotometry. The strongest interactions occur between derivatives of guanine and cytosine. The introduction of the additional ring nitrogen atom in the pharmacologically active 5-azacytosine and 6-azacytosine derivatives does not change the complexing behavior. The positions of the N—H stretching bands in the infared spectra indicate that these complexes have a structure similar to that of the complexes formed between the corresponding pairs of bases in the naturally occurring desoxyribonucleic acid chain.
TL;DR: Linear relationships exist between log kψ and H0 for weakly basic and strongly basic substrates, respectively as discussed by the authors, where H0 is linear free energy as discussed by the authors.
Abstract: Linear relationships exist between log kψ + H0 (for reactions of weakly basic substrates) or log kψ (for reactions of strongly basic substrates) and (H0 + log [H+]). These are linear free energy re...
TL;DR: In this article, the formation of ions of m/e 31, 45, and 59 from a number of alcohols, ethers, and esters has been studied and the following ionic heats of formation have been obtained: C...
Abstract: The energetics and mechanism of formation of ions of m/e 31, 45, and 59 from a number of alcohols, ethers, and esters have been studied. The following ionic heats of formation have been obtained: C...
TL;DR: In this paper, it was shown that in dimethylacetamide solution rhodium trichloride is an effective homogeneous catalyst for the reduction of maleic acid to succinic acid by hydrogen, the reaction proce...
Abstract: The anionic complexes [RhCl6]3−, [Rh(H2O)Cl5]2−, and [Rh(H2O)2Cl4]− activate molecular hydrogen for the reduction of ferric ion in aqueous acid solution; the catalytic activity increased with increasing number of chloride ligands present. Cationic and neutral chloroaquorhodium(III) complexes did not homogeneously catalyze the reduction of ferric ion, the complexes themselves being reduced to metallic rhodium, a powerful heterogeneous catalyst.Chloro complexes of rhodium(III) and rhodium(I) were not effective catalysts in aqueous solution for the homogeneous hydrogenation of the olefinic bond in maleic acid. Anionic chlororhodate(III) complexes were reduced by hydrogen to the univalent state, this state being stabilized against further reduction to the metal by complexing with the maleic acid present. Preliminary studies indicate that in dimethylacetamide solution rhodium (III) trichloride is an effective homogeneous catalyst for the reduction of maleic acid to succinic acid by hydrogen, the reaction proce...
TL;DR: In this article, the authors measured the stochastic properties of substituted phenols with peroxy radicals at 65 °C and showed that 2,4,6-tri-substituted phenols generally have stoichiometric factors of 2.0 or less.
Abstract: The stoichiometries for the oxidation of some substituted phenols with cumyl peroxy radicals at 65 °C have been measured. The results can be correlated generally with the expected phenolic oxidation products. Phenols with one or two unsubstituted ortho positions can react with more than 2 peroxy radicals per molecule. A maximum stoichiometry of 2.6 peroxy radicals was obtained with 2,4-dimethylphenol. 2,4,6-Tri-substituted phenols generally have stoichiometric factors of 2.0 or less.
TL;DR: A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysacchides obtained from each of the organisms designated in the title as mentioned in this paper.
Abstract: A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysaccharides obtained from each of the organisms designated in the title. The five galactomannans I were homogeneous under conditions of electrophoresis and ultracentrifugation and had high positive specific rotations. The major constituent monosaccharide was D-mannose; amounts of D-galactose ranged from nil for the polysaccharide from T. rubrum to 13% for that from T. schonleinii. Methylation and hydrolysis of the five galactomannans I yielded varying amounts of the following: 2,3,5,6-tetra-O-methyl-D-galactose (not present in the products from T. rubrum), 2,3,4,6-tetra-O-methyl-D-mannose, 2,3,4-tri-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4-di-O-methyl-D-mannose, and 3,5-di-O-methyl-D-mannose. Periodate oxidation results agreed with the methylation studies. The gross structural features of each galactomannan I appear to be the same, namely, a basic ...
TL;DR: In this article, the reaction of commercial methyllithium with methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside pro...
Abstract: 4,6-O-Benzylidene-D-glucal has been prepared by the reaction of benzaldehyde with D-glucal. The reaction of commercial methyllithium with methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside pro...
TL;DR: The Chlorobium chlorophylls (660) consist of six different pigments, all of which are derivatives of δ-alkyl-2-desvinyl 2-α-hydroxyethyl pyropheophorbideα.
Abstract: The Chlorobium chlorophylls (660) consist of six different pigments, all of which are derivatives of δ-alkyl-2-desvinyl-2-α-hydroxyethylpyropheophorbideα The six compounds differ in their substituents at C4(isobutyl, n-propyl, ethyl), C5 (ethyl, methyl), and Cδ (ethyl, methyl)
TL;DR: In this article, the rates of production of methane and butane in pyrolysis of ethane have been measured over the temperature range 550-620 °C and at pressures of 40-600 mm.
Abstract: The rates of production of methane and butane in the pyrolysis of ethane have been measured over the temperature range 550–620 °C and at pressures of 40–600 mm. At high pressure the rates of format...
TL;DR: The mass spectra of the monohydroxyquinolines, the monomethoxyquinoline, N-methyl-2-quinolone, and N-methoxyquinoline have been recorded.
Abstract: The mass spectra of the monohydroxyquinolines, the monomethoxyquinolines, N-methyl-2-quinolone, and N-methyl-4-quinolone have been recorded. The isomeric hydroxy compounds vary somewhat in the stability of the molecular ion, but all show the same fragmentation mechanism. Two general fragmentation patterns are discernible in the spectrum of each of the monomethoxyquinolines, but there is considerable variation among the isomers in the extent to which the two patterns occur. In addition, 8-methoxyquinoline undergoes a peculiar fragmentation wherein all three methyl hydrogens are lost. The 3-methoxy compound is unusual in that loss of 43 mass units from the molecular ion occurs in one step. Deuterium- and 13C-labelling experiments have proved to be useful in interpreting the fragmentation pathways. The spectra of the two N-methylquinolones prove that O to N methyl rearrangement does not occur to any significant extent upon electron impact.
TL;DR: In this paper, the authors measured absolute rate constants for autoxidation of five hydrocarbons under a variety of conditions and obtained the propagation (kp) and termination (kt) rate constants at 30 °C.
Abstract: Absolute rate constants have been measured for the autoxidation of five hydrocarbons under a variety of conditions. The propagation (kp) and termination (kt) rate constants at 30 °C (in l mole−1 s−...
TL;DR: In this paper, a brominated phenolic compound, isolated in 5% yield from the red alga Polysiphonialanosa, has been characterized as 2,3-dibromobenzyl alcohol 4,5-disulfate, dipotassium salt.
Abstract: A new brominated phenolic compound, isolated in 5% yield from the red alga Polysiphonialanosa, has been characterized as 2,3-dibromobenzyl alcohol 4,5-disulfate, dipotassium salt. The structural determination, synthesis, and properties of this compound and its derivatives are described.