Showing papers in "Canadian Journal of Chemistry in 1967"
TL;DR: In this paper, the authors measured absolute rate constants for the autoxidation of a large number of hydrocarbons at 30 °C and showed that the rate constants depend on the structure of the hydrocarbon and also on the chain-carrying peroxy radical.
Abstract: Absolute rate constants have been measured for the autoxidation of a large number of hydrocarbons at 30 °C. The chain-propagating and chain-terminating rate constants depend on the structure of the hydrocarbon and also on the structure of the chain-carrying peroxy radical. With certain notable exceptions which are mainly due to steric hindrance, the rate constants for hydrogen-atom abstraction increase in the order primary < secondary < tertiary; and, for compounds losing a secondary hydrogen atom, the rate constants increase in the order unactivated < acyclic activated by a single π-electron system < cyclic activated by a single Π-system < acyclic activated by two π-systems < cyclic activated by two π-systems. The rate constants for chain termination by the self-reaction of two peroxy radicals generally increase in the order tertiary peroxy radicals < acyclic allylic secondary cyclic secondary acyclic benzylic secondary < primary peroxy radicals < hydroperoxy radicals.
232 citations
TL;DR: In this paper, the rate constants for formation of the protonated molecule by ion-molecule reactions in CH3OH, (CH3)2O, and CH4 have been studied both at thermal energies and at 3.4 eV ion exit energy with a new...
Abstract: The rate constants for formation of the protonated molecule by ion–molecule reactions in CH3OH, (CH3)2O, and CH4 have been studied both at thermal energies and at 3.4 eV ion exit energy with a new ...
187 citations
TL;DR: In this paper, the problem of the equilibrium configuration of the ethylene glycol molecule was investigated by measuring the infrared spectra of the vapor (up to 125 °C), liquid, and solid phases between 100 and...
Abstract: The problem of the equilibrium configuration of the ethylene glycol molecule was investigated by measuring the infrared spectra of the vapor (up to 125 °C), liquid, and solid phases between 100 and...
146 citations
TL;DR: In this paper, a general synthetic procedure leading to cyclic hydrogen phosphites was devised and the effect of solvent on the P==O and P-H infrared stretching modes of cyclic Hydrogen Phosphites and thiophospores was investigated.
Abstract: A general synthetic procedure leading to cyclic hydrogen phosphites has been devised. The effect of solvent on the P==O and P—H infrared stretching modes of cyclic hydrogen phosphites and thiophosp...
116 citations
TL;DR: Reduction with sodium in liquid ammonia of l-thiazolidine-4-carboxylic acid (II) leads, depending on the reaction procedure followed, to N-methyl-l-cysteine (I) or a mixture of Nmethyl-L-Cysteine...
Abstract: Reduction with sodium in liquid ammonia of l-thiazolidine-4-carboxylic acid (II) leads, depending on the reaction procedure followed, to N-methyl-l-cysteine (I) or a mixture of N-methyl-l-cysteine ...
99 citations
TL;DR: The infrared spectra of some aldehyde and ketone thiosemicarbazones have been compared over the region 1'200 to 700'cm−1 with the corresponding selenosemic carbazones as mentioned in this paper.
Abstract: The infrared spectra of some aldehyde and ketone thiosemicarbazones have been compared over the region 1 200 to 700 cm−1 with the spectra of the corresponding selenosemicarbazones. A band in the fo...
98 citations
TL;DR: In this paper, the authors showed that the absolute rate constant for the self-reaction of hydroperoxy radicals (chain termination) in nonpolar solvents is very much higher than previously reported values in aqueous media.
Abstract: The hydroperoxy radical (HOO·) is the main chain propagating and terminating radical in the autoxidation of dilute solutions of 1,4-cyclohexadiene and 1,4-dihydronaphthalene in chlorobenzene at 30 °C The absolute rate constant for the self-reaction of hydroperoxy radicals (chain termination) in nonpolar solvents is very much higher than previously reported values in aqueous media
95 citations
TL;DR: In this paper, the structures of the hordatines were deduced by degradative and spectroscopic studies and by the synthesis of some degradation products, and a synthesis of racemic Hordatine A analogous to its probable biogenesis was achieved by the oxidative coupling of coumaroylagmatine.
Abstract: Careful fractionation of extracts prepared from barley coleoptiles gave small amounts of pure hordatines A and B and substantial amounts of a mixture of their glucosides. The structures of the hordatines were deduced by degradative and spectroscopic studies and by the synthesis of some degradation products. A synthesis of racemic hordatine A analogous to its probable biogenesis was achieved by the oxidative coupling of coumaroylagmatine.The possible role of the hordatines in lignification is briefly discussed.
93 citations
TL;DR: In this article, the densities of aqueous solutions of the homologous salts RNH3Br, where R varies from H to n-octyl, have been measured at 25 °C to the sixth decimal place by a float method.
Abstract: The densities of aqueous solutions of the homologous salts RNH3Br, where R varies from H to n-octyl, have been measured at 25 °C to the sixth decimal place by a float method. From this series, it is possible to study the transition in behavior of typical simple salts to long-chain micellar salts. The apparent molal volumes extrapolated to infinite dilution can be used to evaluate the additivity of the volume of the methylene groups. The concentration dependence of the apparent molal volumes and the change in volume during micelle formation can be interpreted in terms of a competition between the increase in ice-likeness of water and loss of free space near the solute during hydrophobic hydration. The present results show no indications of dimerization of the cations below the critical micelle concentration.
91 citations
TL;DR: The inhibition of the oxidation of styrene by the stable aliphatic nitroxide radical, 2,2,6,6-6-tetramethyl-4-piperidone (I), and two stable aromatic Nitroxide radicals, 4,4′-dimethoxydiphe...
Abstract: The inhibition of the oxidation of styrene by the stable aliphatic nitroxide radical, 2,2,6,6-tetramethyl-4-piperidone nitroxide (I), and two stable aromatic nitroxide radicals, 4,4′-dimethoxydiphe...
91 citations
TL;DR: The mass spectra and appearance potentials for the major ions from Ni(CO)4, Fe(CO), Cr(CO)-6, Mo(Co)6, W(Co), and V(Co)-6 have been measured in this article.
Abstract: The mass spectra and appearance potentials for the major ions from Ni(CO)4, Fe(CO)5, Cr(CO)6, Mo(CO)6, W(CO)6, and V(CO)6 have been measured. Heats of formation have been calculated for 39 ions of ...
TL;DR: In this article, an H− acidity function based on the ionization of 24 substituted anilines and diphenylamines was established in the system dimethyl sulfoxide -water - tetramethylammonium hydroxide.
Abstract: An H− acidity function based on the ionization of 24 substituted anilines and diphenylamines has been established in the system dimethyl sulfoxide – water – tetramethylammonium hydroxide. The H− of...
TL;DR: The structural studies support the observation that the mannans are very similar serologically and chemically to Candida species, and indicate that most of the glycosidic linkages were in the α configuration.
Abstract: Mannans have been isolated from cells of the following Candida species: C. albicans (serotype A), C. albicans (serotype B), C. parapsilosis, C. stellatoidea, and C. tropicalis. Methylation and hydrolysis of each mannan yielded the following methyl ethers of d-mannose (with only small variations in the relative amounts): 2,3,4,6-tetra-O-methyl-d-mannose, 3,4,6-tri-O-methyl-d-mannose (major), 2,3,4-tri-O-methyl-d-mannose (minor), 2,4,6-tri-O-methyl-d-mannose (minor), 3,4-di-O-methyl-d-mannose, and 3,5-di-O-methyl-d-mannose. The mannans therefore contained a predominance of 1 → 2 linkages in the linear portions, with smaller amounts of 1 → 6 and 1 → 3 linkages. Branching occurred through C-2 and C-6 of d-mannopyranose and d-mannofuranose units, and branches were terminated by d-mannopyranose units. The specific rotations of the mannans indicated that most of the glycosidic linkages were in the α configuration. The structural studies support the observation that the mannans are very similar serologically and ...
TL;DR: The crystal structures of RuS2, OsS2 and OsTe2 were refined isotropically by least squares from powder diffractometer data using individual temperature factors.
Abstract: The crystal structures of RuS2, OsS2, RuTe2, and OsTe2 were refined isotropically by least squares from powder diffractometer data using individual temperature factors. The resulting positional par...
TL;DR: In this paper, the activation parameters of a series of alkyl chloroformates and dimethyl carbamyl chloride in water have been determined and the results indicate that, with incr...
Abstract: The activation parameters ΔH≠, ΔS≠, and ΔCP≠ for the hydrolyses of a series of alkyl chloroformates and dimethylcarbamyl chloride in water have been determined. The results indicate that, with incr...
TL;DR: In this paper, a method of determining the stoichiometry of metastable phases from nucleation characteristics is described and applied to calcium phosphate precipitation and the stochastic ratio [Ca]/[P] is s
Abstract: A method of determining the stoichiometry of metastable phases from nucleation characteristics is described and is applied to calcium phosphate precipitation. The stoichiometric ratio [Ca]/[P] is s...
TL;DR: In this article, the effects of substituting a substituting element with a deuterated analog in the infrared spectra of ϵ-Zn(OH)2, β-ZNOHCl, ZnOHCl and ZnClF were investigated.
Abstract: Infrared spectra of ϵ-Zn(OH)2, β-ZnOHCl, ZnOHF, Zn5(OH)8Cl2, and Zn5(OH)8Cl2·H2O and their deuterated analogues in the range 2.5–16 μ are reported for the first time. The effects of substituting a ...
TL;DR: The infrared spectra of the complexes [Ru(NH3)6]X2 and [RuNH3]X3 have been measured in the solid state between 4 000 and 4 000.
Abstract: The infrared spectra of the complexes [Ru(NH3)6]X2 and [Ru(NH3)6]X3, where X = Cl−, Br−, I−, BF4− and [Ru(NH3)5X]X2, where X = Cl−, Br− and I−, have been measured in the solid state between 4 000 –...
TL;DR: The nucleophilic behavior of zero-valent platinum complexes toward a variety of covalent molecules has been studied as mentioned in this paper, and it appears that the rate of reaction appears to depend little on the electronegativity of the carbon atom to which the halogen is bonded.
Abstract: The nucleophilic behavior of zero-valent platinum complexes toward a variety of covalent molecules has been studied. Although too rapid for convenient kinetic studies to be made, oxidative addition reactions of this type enable a number of novel organo-platinum(II) derivatives to be prepared without the use of conventional organometallic reagents. Cleavage of carbon–halogen bonds in unsaturated molecules of the type —C≡≡CX and CH==CHX is very fast, and the rate of reaction appears to depend little on the electronegativity of the carbon atom to which the halogen is bonded. Similar reactions occur between the zero-valent platinum species and acyl and sulfonyl halides. The S-sulfinate and acyl platinum derivatives, when heated, lose SO2 and CO, respectively, with the formation of alkyl or aryl platinum complexes.
TL;DR: In this article, the nuclear magnetic resonance and infrared spectra of these compounds provided strong evidence that ring C in the alkaloid is in a boat conformation in solution, and the reduction of the deuterated sparteine confirmed the same geometry.
Abstract: Methods have been developed for preparing 17α-deuterio-, 17β-deuterio-, and l7-dideuteriolupanines. The nuclear magnetic resonance and infrared spectra of these provided strong evidence that ring C in the alkaloid is in a boat conformation in solution. Reduction of these compounds to the deuterated sparteines confirmed the same geometry for sparteine. In contrast, moilodeuteration of aphylline at C-17 showed that i t had an all-chair conformation in solution. 13β-Hydroxylupanine was shown to have the same conformation as lupanine in solution, but to adopt an all-chair conformation in the solid state. Interpretation of the nuclear magnetic resonance spectra enabled the conformation of ring C of 15-oxosparteine to be assigned. The oxidation and reductions involving C-17 of lupanine have been shown to be highly stereospecific, and an interpretation is given of the difference betmeen the dehydrogenation of lupanine by mercuric acetate and those by Nbromosuccinimide or by the mercuric acetate - ethylenediatnin...
TL;DR: In this article, the authors measured the possible cross-disproportionation reactions of radicals relative to their rates of cross-combination, and compared with auto-disportionation-to-combinatat...
Abstract: Rates of the possible cross-disproportionation reactions of these radicals relative to their rates of cross-combination, have been measured and are compared with auto-disproportionation-to-combinat...
TL;DR: In this article, the Cauchy (Lorentz) contour was modified to conform with the finite spectral slit distortion of the spectrophotometer and the fitting procedures using transmittance ordinates were compared and the dependence of the optimized indices on the band distortion and data range were analyzed.
Abstract: Simulated infrared absorption bands of condensed phase systems have been fitted with simple analytical functions by least-squares procedures. The bands were of Cauchy (Lorentz) contour and were modified to conform with the finite spectral slit distortion of the spectrophotometer. Cauchy, Cauchy–Gauss product, and Cauchy–Gauss sum functions were used in the fitting procedures using transmittance ordinates. The fits achieved were compared and the dependence of the optimized indices on the band distortion and data range were analyzed. Some preference for the Cauchy–Gauss sum function is indicated.
TL;DR: In this paper, β-Zn3(PO4)2 crystallizes in the monoclinic space group P 21/c with lattice parameters, a = 9.393(3)
Abstract: β-Zn3(PO4)2 crystallizes in the monoclinic space group P 21/c with lattice parameters, a = 9.393(3) A, b = 9.170(6) A, c = 8.686(3) A, β = 125.73(10)°, and Z = 4. The three independent cations are ...
TL;DR: In this article, four N,N -dialkyldithiocarbamate esters have been prepared and examined by nuclear magnetic resonance (NMR) and four N-alkyl resonances have been made.
Abstract: Four N,N -dialkyldithiocarbamate esters have been prepared and examined by nuclear magnetic resonance. From the temperature variation of the N-alkyl resonances, estimates of the barriers to rotation about the C—N bond have been made. Activation energies of the order 10 to 12 kcal provide evidence for an appreciable amount of C—N double bonding; this lends support to the assignment of the "thioureide" band in present and earlier infrared studies.
TL;DR: Methyl 4,6-O-(hydroxyisopropylidene)-α-d-glucopyranosides (X and XI) were synthesized and the ketal configuration of X was established by a Smith degradation to 1,3-O(hydroxyiso-propylidenes)-l-erythritol (XIII) as discussed by the authors.
Abstract: Methyl 4,6-O-(hydroxyisopropylidene)-α-d-glucopyranosides (X and XI) were synthesized and the ketal configuration of X was established by a Smith degradation to 1,3-O-(hydroxyiso-propylidene)-l-erythritol (XIII), which was prepared from 2,8-anhydro-1-deoxy-d-glycero-β-d-gulo-octulopyranose (XVI). Methyl 4,6-O-(hydroxyisopropylidene)-α-d-galactopyranosides (II and V) were prepared and their ketal configurations determined by comparison of molecular rotations. Methyl 4,6-O-(1-carbomethoxyethylidene)-α-d-galactopyranosides (IX and XII) from II and V and methyl 4,6-O-(1-carbomethoxyethylidene)-α-d-glucopyranosides (XIV and XV) from X and XI were utilized for this purpose. Also, the hydrogen-bonding characteristics of methyl 4,6-O-(hydroxyisopropylidene)-2,3-di-O-methyl-α-d-galactopyranosides (III and VI) from II and V were compared with those of methyl 4,6-O-(hydroxyisopropylidene)-2,3-di-O-methyl-α-d-glucopyranosides (VII and VIII) from X and XI. Based on the finding that X contains an axial C-methyl group, ...
TL;DR: In this paper, a kinetic study at different pH values indicates that the monoanion of oxalacetic acid is the major active species which decarboxylates spontaneously.
Abstract: The kinetic study at different pH values indicates that the monoanion of oxalacetic acid is the major active species which decarboxylates spontaneously. The decarboxylation of the monoanion is favo...
TL;DR: In this paper, the replacement of a hydroelectric power station with a thermal sensor is discussed. But the results show that the replacement is not suitable for all applications, and the results are limited to the case of β-ZnOHCl and ZnOHF.
Abstract: Thermogravimetric (t.g.a.) and differential thermal analyses (d.t.a.) of ϵ-Zn(OH)2, Zn5(OH)8Cl2.H2O, β-ZnOHCl, and ZnOHF are reported and discussed. The results show that the replacement of a hydro...
TL;DR: Cadmium pyrovanadate as discussed by the authors is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO4 tetrahedra while the cation resides within a distorted octahedron of oxygen atoms.
Abstract: Cadmium pyrovanadate crystallizes in the C2/m space group with lattice parameters a = 7.088(5) A, b = 9.091(5) A, c = 4.963(5) A, β = 103°21(5)′, and z = 2. This crystal is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO4 tetrahedra while the cation resides within a distorted octahedron of oxygen atoms. The anion has a linear V—O—V group, but, as with the isostructural pyrophosphates, the central oxygen atom shows an anomalously high thermal activity. The V—O bond distances are 1.76 A for the inner bond and 1.70 A for the terminal bond. The bond angles about the anion and cation are similar to those found for the other analogues of thortveitite.