摘要:

The rate of hydrolysis of iodopentaaquochromium(III) ion has been measured as a function of pressure (0.1 to 250 MPa) and hydrogen ion concentration (0.1 to 1.0 mol kg−1) at 298.2 K and ionic strength 1.0 mol kg−1(aqueous HClO4–LiClO4). The volumes of activation for the acid independent and inversely acid dependent hydrolysis pathways are −5.4 ± 0.5 and −1.6 ± 0.3 cm3 mol−1respectively, and are not detectably pressure-dependent. Consideration of these values, together with the molar volume change of −3.3 ± 0.3 cm3 mol−1determined dilatometrically for the completed hydrolysis reaction, indicates that the mechanisms of the two pathways are associative interchange (Ia) and dissociative conjugate base (Dcb) respectively.

ISSN:0008-4042    

DOI:10.1139/v75-534

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The hydrolysis of the chromate ester, derived from 1-methylcyclohexanol, was studied by electrochemical methods. Progressive and complete hydrolysis in an open or closed system yields chromic acid and 1-methylcyclohexanol. No evidence of the presence of monoester was detected. In a closed system, where most of the hydrolyzed alcohol is retained in solution, a side reaction between chromic acid and the alcohol has been detected and followed by conductivity measurements.Electrochemical characteristics of pure iron immersed in aqueous solutions containing hydrolyzed ester were found to be identical to those in aqueous solutions containing equivalent quantities of CrVIas CrO3. Sulfuric acid additions to the above solutions still give comparable electrochemical characteristics; however, the anodic current in the passive region was found to be less for solutions containing hydrolyzed ester than for solutions containing equivalent quantities of CrVIas CrO3.

ISSN:0008-4042    

DOI:10.1139/v75-535

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A kinetic study of the oxidation of a series of substituted benzyl alcohols and benzaldehydes by neutral aqueous sodium dichromate has been completed. The aldehydes are more resistant to oxidation because the reaction mechanism presumably involves hydration prior to oxidation, and under the conditions employed the extent of this hydration is suppressed. These conclusions are consistent with the activation parameters which indicate that the difference in oxidation rate is due to a more negative entropy of activation for the aldehydes.

ISSN:0008-4042    

DOI:10.1139/v75-536

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Diazotization of 2′-aminoacetophenone, followed by coupling with primary aliphatic amines, affords unstable triazenes which readily undergo cyclodehydration over neutral alumina to give 3-alkyl-4-methylene-1,2,3-benzotriazines (5a-d). 3-Aryl-4-methylene-1,2,3-benzotriazines (8a-c) are likewise obtained by cyclodehydration of the stable 1-(ortho-acetylphenyl)-3-aryltriazenes (7a-c). Attempted synthesis of the unsubstituted 4-methylene-1,2,3-benzotriazine (5e), by the same method, did not succeed. 4-Hydroxy-1,2,3-benzotriazines (4) are postulated as intermediates in the cyclodehydration; this hypothesis is supported by the isolation of the stable 4-hydroxy-1,2,3-benzotriazine (12) from the coupling reaction of methylamine with the diazonium salt derived fromortho-aminobenzophenone. An account of a preliminary study of the thermolysis of 3-methyl-4-methylene-1,2,3-benzotriazine (5a) is included.

ISSN:0008-4042    

DOI:10.1139/v75-537

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The monoacids derived from trithiane, tetrathiocane, and pentathiecane, C3H5S3X (X = CO2H, COSH, CS2H), C4H7S4X (X = CO2H, CS2H), and C5H9S5X (X = CO2H, CS2H) and the lithium salts C3H5S3SO2Li, C4H7S4SO2Li, and C5H9S5SO2Li have been prepared and their reactions studied. The corresponding esters C3H5S3CO2R (R = CH3, C2H5,n-C3H7,i-C3H7n-C4H9,n-C5H11), C3H5S3COSCH3, C4H7S4CO2R (R = CH3, C2H5) and the ammonium salts, C3H5S3CO2NH4, C3H5S3CS2NH4, C3H5S3CS2N(n-Bu)4, C4H7S4CO2NH4, (C4H7S4CO2)2(Me2NHCH2)2, and C5H9S5CO2NH4have been isolated. The reactions of the acid anion with various metal ions have been investigated. Nuclear magnetic resonance, mass, and infrared spectroscopic data of some of the products are reported.

ISSN:0008-4042    

DOI:10.1139/v75-538

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The preparation of the trimethylgermyl esters ofN,N-dimethylcarbamic,N,N-dimethylmonothiocarbamic, andN,N-dimethyldithiocarbamic acids and the trimethylplumbyl ester ofN,N-dimethylmonothiocarbamic acid is reported. Some of these esters exhibit temperature dependent n.m.r. spectra. Infrared and u.v. spectra for these and related compounds are also described.

ISSN:0008-4042    

DOI:10.1139/v75-539

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Activation parameters for hindered rotation about the C—N bond have been obtained for some trimethylgermyl, trimethylplumbyl, andtert-butyl esters ofN,N-dimethylcarbamic,N,N-dimethylmonothiocarbamic, andN,N-dimethyldithiocarbamic acids. These are compared with previous results for some group IV esters and general considerations as to factors influencing barriers to rotation are discussed. It was found that the degeneracy of theN-methyl resonances observed in the room or low temperature1H spectra appeared also to extend to the room temperature13C spectra. A 'steric' effect was noted on the carbonyl and thiocarbonyl resonances.

ISSN:0008-4042    

DOI:10.1139/v75-540

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

An approximate relationship of the formwhereis the mean potential acting upon andVthe mean volume of an electron in a closed shell of an atom has previously been proposed. This concept of a simple relationship between the sizes and energies of atomic orbitals which is predicted by simple quantum mechanical arguments has been further examined in this present work. The potential energy for a series of two electron atoms and ions has been replaced by the total electronic energy as these two quantities are simply connected by the virial theorem. For polyelectronic atoms, a quantity per electron pair which sums to the total electronic energy has been used. The volume of theith atomic orbitalhas been calculated from its size as previously defined in terms of the spherical quadratic operator evaluated at the orbital centroid of charge. A relationship of the above form between the sizes and energies of atomic orbitals holds well for core orbitals but gradually deteriorates on going from the innermost (core) to outermost (valence) shell.

ISSN:0008-4042    

DOI:10.1139/v75-541

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Equilibrium geometries and energies are obtained for SHn(n = 0, 1, 2, 3) neutral and charged species by the Roothaan LCAO–MO–SCF method. A large gaussian basis set includingdandppolarization functions was employed. The calculated ionization potentials, electron, proton, hydrogen, and hydride affinities are discussed as well as compared with similar previously calculated properties for OHn(n = 0, 1, 2, 3) species.

ISSN:0008-4042    

DOI:10.1139/v75-542

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A green intermediate, observed during reduction of 9,10-anthraquinone-2-sulfonate (A) to the corresponding anthrahydroquinone (AH2) in acidic aqueous solution, has been identified as a quinhydrone-like charge-transfer complex of A and AH2. Spectrophotometric and potentiometric measurements have shown that changes in the slope of the potentiometric titration curves with varying initial [A] are caused only by this complexand not by any semiquinone radical (AH·) or radical anion (A·−) intermediate. The very low semiquinone formation constant in acidic solution indicates that the pKaof AH· < 7.0. Electrochemically determined pKavalues for similar radicals in the range 8.5–10.5 are invalid because of interference by charge-transfer complexes of this type.

ISSN:0008-4042    

DOI:10.1139/v75-543

出版商:NRC Research Press    

年代:1975

数据来源: NRC