摘要:

The density, dielectric constant, change of volume on mixing, refractive index, surface tension, and viscosity of the methanol–cyclohexane system have been investigated experimentally at temperatures ranging from 25° to 50°. The same properties of the binary systems acetone–methanol and acetone–cyclohexane, as well as of the ternary system methanol–cyclohexane–acetone were determined experimentally at 25°. The critical region of the partially miscible system methanol–cyclohexane has been investigated by determining the above physical properties at temperatures above and below the critical solution temperature. A similar investigation of the ternary system has been made, isothermally at 25°, by investigating solutions lying in the neighborhood of the plait point.The surface tension or a derived function of it,viz. the molecular surface energy, does not show a horizontal portion of the isotherm in the methanol–cyclohexane system, but the ternary system does show such a constant surface tension, probably fortuitously, all along the tangential line. The viscosity exhibits anomaly.All the systems show azeotropic behavior. The methanol–cyclohexane and acetone–cyclohexane systems show marked deviations in molar polarization from linearity and this agrees with the thermodynamic data, which indicate larger than unity values for the activity coefficients of the components' behavior (1). The viscosity isotherms of all these systems give no indication of the formation of any stable compound.

ISSN:0008-4042    

DOI:10.1139/v72-176

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The mercury-photosensitized decomposition of neopentane was investigated from 230 to 335 °C, and at pressures from 3 to 280 Torr. The following were identified as primary products and their initial rates of formation measured over a range of conditions: H2, CH4, C2H6,i-C4H8, neohexane and dineopentyl. The results are explained in terms of a mechanism in which the primary step involves the split of neopentane (Nptn) into the neopentyl radical (Nptl) and H; Nptl then undergoes further reactions including a split intoi-C4H8 + CH3. Estimates are made of the free-radical concentrations at various temperatures and pressures. A simplified steady-state treatment is worked out and is shown to explain the pressure dependence of the rates of formation of the various primary products.

ISSN:0008-4042    

DOI:10.1139/v72-177

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The results of Part I are further analyzed with reference to certain of the elementary free-radical processes occurring. A fall-off in the methyl radical combination is observed at low pressures. Comparison of this process with the CH3 + neopentane abstraction yields for the latter an activation energy of 11.5 kcal/mol and a frequency factor of 4.9 × 1011 cc mol−1s−1. The relative importance of CH3 + neopentyl and neopentyl + neopentyl is compared. The decomposition of the neopentyl radical intoi-C4H8 + CH3shows a fall-off at low pressures; the limiting activation energy at high pressures is 29.0 kcal/mol, while that at low pressure is 17.1 kcal/mol. The former value leads to 6.7 kcal/mol for the heat of formation of the neopentyl radical at 25 °C, to 21.3 kcal/mol for the heat of its dissociation intoi-C4H8 + CH3, and to 98.5 kcal/mol for the heat of dissociation of neopentane into neopentyl + H. Entropy values are also calculated in an approximate manner.

ISSN:0008-4042    

DOI:10.1139/v72-178

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The following were identified as secondary products of the mercury-photosensitized decomposition of neopentane, and their maximal rates measured over a range of conditions: C2H4, C3H6, C3H8,i-C4H10, 2,2,3,3-tetramethylbutane, and 2,2,4,4-tetramethylpentane. A mechanism is proposed which explains the kinetics of formation of these products. It involves the reaction of H atom withi-C4H8formed as a primary product; this leads to the formation of C4H9which reacts further; one of its products is C3H6which also reacts with H atoms.

ISSN:0008-4042    

DOI:10.1139/v72-179

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The crystal structure of KIO3•HIO3has been determined by three-dimensional single crystal X-ray diffraction and by neutron powder diffraction. The crystallographic data area = 7.025(2),b = 8.206(2),c = 21.839(5) Å, β = 97.98(2)°, space groupP21/c,Z = 8 units KIO3•HIO3. The residualwas 0.048 for 7516 independent X-ray reflections measured on a three-circle diffractometer withZr-filtered Mo radiation. The results of the present study show good qualitative agreement with the structure recently determined by Chan and Einstein (7). The HIO3andgroups are pyramidal, the I—O(H) bonds vary from 1.898 to 1.939(4) Å and the I—O bonds from 1.786 to 1.827(4) Å, these lengths are not corrected for the effects of thermal motion. Strong O—I … O interactions and electrostatic attractions between K+and Oδ−give slabs of thicknessThe slabs are connected by hydrogen bonds of 2.710 and 2.694 Å.

ISSN:0008-4042    

DOI:10.1139/v72-180

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The slope method has been applied to the determination of the cumulative formation constants ofand Ag(OH)CN−and to the measure of the solubility product of AgCN, in 1 MNaClO4, at 25 °C.

ISSN:0008-4042    

DOI:10.1139/v72-181

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The minimum energy conformation of 2-methoxyethanol (CH3OCH2CH2OH) has been determined from an analysis of its microwave spectrum. The rotational constants of the normal species are:A = 12982.35,B = 2742.48, andC = 2468.10 MHz; the dipole moment components are μa = 2.03, μb = 1.15,and μ = 2.36 ± 0.03 D. For the CH3OCH2CH2OD species:A = 12385.71,B = 2724.74, andC = 2431.42 MHz. The conformation consistent with this data isgaucheabout each of the C—C, C—O(H) and C—O(ether) bonds, having dihedral angles of 57 ± 3°, 45 ± 5°, and 8 ± 3°, respectively. This distorted conformation is one in which the hydroxyl hydrogen atom is approximately aligned with the nearest sp3lone pair electrons of the ether oxygen atom. Transitions in three excited torsional states have also been observed but no other rotational isomer was detected.

ISSN:0008-4042    

DOI:10.1139/v72-182

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Coordination compounds between AlCl3or AlBr3and (CH3)2SO or (CD3)2SO have been prepared. Two different solid compounds (AlX3)•(dmso)1.5and AlX3•(dmso)6have been characterized. The vibration spectra show that they are ionic,(I) and [Al(dmso)6]3+•3X−(II). A complete assignment is proposed. Results are in good agreement with aD3dsymmetry for the cation of compound (I) andC2hfor the cation of compound (II). Strong interaction between the X−ions and the methyl groups of the form (II) exist.The (Al—O) bond force constant is close to 1.8 × 105 dynes cm−1.

ISSN:0008-4042    

DOI:10.1139/v72-183

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Reactions ofN-chloroazacyclooctane andN-chloroazacyclononane are described which give good yields of bicyclic amines. These are: (a) short chain homolytic reactions involvingneutralnitrogen radicals initiated by ferrous ion or metallic silver; (b) apparent homogeneous reactions involving silver ion and bases; (c) reactions using silver oxide suspension which also require added bases.Both rate and product composition for (b) and (c) are sensitive to oxygen indicating that they are homolytic processes, probably initiated by traces of silver metal. No evidence for involvement of discrete nitrenium ions was found. However, reaction ofN-chloroisoquinuclidine with silver ions has the character of a heterolytic process, giving products completely distinct from those from its homolytic decomposition. The addition ofneutralpiperidino radicals to styrene is described.

ISSN:0008-4042    

DOI:10.1139/v72-184

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Twenty-one 4-alkoxypyridines and their correspondingN-methyl-4-alkoxypyridinium iodides have been prepared and the latter pyrolyzed at temperatures ranging from room temperature to 185° to give the olefins derived from the alkyl moiety in high yields.

ISSN:0008-4042    

DOI:10.1139/v72-185

出版商:NRC Research Press    

年代:1972

数据来源: NRC