摘要:

For five pentanediols the infrared spectra, the dipole moments, and the static dielectric constants show an increasing degree of internal hydrogen bonding with increasing proximity of the OH groups. The dielectric dispersion loci at low temperatures are skewed arcs over most of the dispersion range. Values of the parameter β decrease from ca. 1 to 0.55 in the series 1,5-, 1,4-, 1,2-, 2,4-, and 2,3-pentanediol, which is also the order of increasing relaxation time τ0at low temperatures. Increased τ0is associated with increased irregularity of intermolecular hydrogen bonding, an effect which supports the view that relaxation proceeds by a co-operative mechanism which is facilitated by regularity in the liquid structure. At temperatures of "structural relaxation", values of log τ0are linear in (T–T∞)−1; the proportionality constants, but not theT∞'s, are the same for all five diols.The experimental behavior at relatively high frequencies departs from both the skewed-arc and Glarum equations, although less from the latter. These departures are compared with the high frequency dispersion regions inn-propanol.

ISSN:0008-4042    

DOI:10.1139/v61-286

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Rate data for the hydrolysis of a series of halohydrins and related compounds in light and heavy water are reported. The solvent isotope effectsfrom these measurements fall into three groups compared with those of simple halides. Thus the presence of a hydroxyl group in proximity to the seat of reaction may lead to increased, decreased, or normal solvent isotope ratios. The abnormal ratios can be interpreted in terms of the effect of anchimeric assistance on the solvation shell in the activation process.

ISSN:0008-4042    

DOI:10.1139/v61-287

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The isotopic composition of hydrogen evolved in the radiolysis of C6D12–C6H12mixtures has been measured in the presence of various amounts of benzene and iodine. The yield of the unimolecular decomposition and the specific yield of the bimolecular reaction are reduced in approximately the same proportion as the yield of total hydrogen. It is concluded that (i) iodine and benzene interact to a comparable extent with both unimolecular and bimolecular decomposition modes, (ii) it is probable that neither of these additives act by scavenging, and (iii) it is probable that they act by quenching a common precursor of the two decomposition modes.

ISSN:0008-4042    

DOI:10.1139/v61-288

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

New assignments are proposed for the fundamental frequencies of SOF2, SOCl2, SO2Cl2, SO2F2, and SO2FBr, based on new measurements of the Raman spectrum of SO2Cl2and previous measurements of the infrared and Raman spectra of these molecules. The fundamental frequencies of these molecules are found to be related to each other and to those of similar molecules when the normal modes are described in terms of characteristic vibrations of the SO, SO2, S(Hal), and S(Hal)2groups.

ISSN:0008-4042    

DOI:10.1139/v61-289

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The Raman spectrum of disulphuryl chloride, S2O5Cl2, has been reinvestigated and the Raman spectra of S2O5F2, S2O5ClF, S3O8Cl2, S3O8F2, and the new compound S3O8ClF are reported for the first time. The vibrational spectra of these polysulphuryl halides are interpreted in terms of characteristic group frequencies by comparison with the vibrational spectra of simple sulphuryl compounds. The spectra are consistent with acyclic structures for the polysulphuryl halides.

ISSN:0008-4042    

DOI:10.1139/v61-290

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The Raman spectra of liquid sulphur trioxide and of sulphur trioxide dissolved in a number of "inert" solvents have been investigated. A detailed analysis of the spectrum of liquid sulphur trioxide supports the earlier suggestion of Gerding and Nijveld that the main polymeric species in liquid sulphur trioxide is the cyclic trimer. Frequencies are assigned for all the Raman active vibrations of the cyclic trimer. These assignments differ substantially from those given previously by Gerding and Nijveld.The spectra of dilute solutions of sulphur trioxide in sulphur dioxide, sulphuryl chloride, carbon tetrachloride, tetrachlorethylene, and trichlorfluormethane (Freon 11) show that the sulphur trioxide is present mainly in the monomeric form at low concentrations while at higher concentrations a polymeric form, which is very probably the trimer, is also present.

ISSN:0008-4042    

DOI:10.1139/v61-291

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The Raman spectra of 12 α,β-unsaturated open-chain and cyclic ketones have been measured in the region of the C = O and C = C stretching vibrations, and the band positions and intensities have been compared with the corresponding bands in the infrared spectra. If due allowance is made for solvent effects, the infrared and Raman bands are observed at the same positions, but the relative intensities of the C = O and C = C bands are different; in particular, the Raman C = O stretching bands of the ketones in thes-trans configuration are from 5 to 10 times more intense than the Raman bands for thes-cis isomers. The cyclics-trans ketones with a hydrogen atom on the α-carbon atom exhibit a solvent-sensitive doubling of the carbonyl maximum similar to that noted previously for certain α,β-unsaturated lactones, unsaturated acid anhydrides, and Δ2-cyclopentenone derivatives. These doublet carbonyl maxima are observed also in the infrared spectra. The C = C frequency is not similarly perturbed and the effect is distinct from the doubling of both the C = O and the C = C bands exhibited by some open-chain α,β-unsaturated ketones that exist in the liquid phase as equilibrium mixtures ofs-cis ands-trans isomers.

ISSN:0008-4042    

DOI:10.1139/v61-292

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

A variable-thickness, variable-temperature absorption cell, modified from the design of Holden, Taylor, and Johnston, has been used to compare the infrared spectrum of diethyl ketone at −75° and +25 °C. The Raman spectrum of diethyl ketone has also been measured at +6°, +25°, and +85 °C, and the proton magnetic resonance spectrum over the range −61° to 104 °C.Both the infrared and Raman spectra exhibit pronounced temperature sensitivity, which is attributed to the presence of at least two conformational isomers in the liquid phase. Possible structures for these isomers are considered. Small but significant chemical shifts are noted in the proton magnetic resonance spectrum.

ISSN:0008-4042    

DOI:10.1139/v61-293

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The infrared and Raman spectra oftrans-Δ3-penten-2-one have been measured over the temperature range +30° to −75° and +85° to +5° respectively. The temperature-dependent changes observed in the spectra indicate that this ketone exists as an equilibrium mixture ofs-cis ands-trans conformational isomers in the liquid state. Thes-trans form is the more stable and is present exclusively in the crystalline solid.Similar measurements have been carried out on Δ3-buten-2-one. The infrared and Raman spectra of this ketone also exhibit temperature effects that can be explained by a similar equilibrium, though the evidence is not as conclusive as fortrans-Δ3-penten-2-one.The influence of alkyl substitution at the α- and β-carbon atoms on the relative stability of thes-cis ands-trans forms of α,β-unsaturated ketones is discussed.

ISSN:0008-4042    

DOI:10.1139/v61-294

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Polarographic study of thiomalic acid has been made in the pH range 1–12.5 using Britton–Robinson buffer at 30°. The half-wave potentialvalues have been used to determine the pK3(SH) value of the acid (pK3 = 10.55).The diffusion current obtained in these experiments has been utilized to calculate the diffusion coefficients of the different charged species of thiomalic acid. The values thus obtained for the respective species are H3A = 1.20 × 10−5 cm2/sec; H2A− = 1.16 × 10−5 cm2/sec; HA−− = 1.08 × 10−5 cm2/sec; and A−−− = 7.67 × 10−6 cm2/sec.The standard potential of the reactionhas been calculated as +0.266 volt vs. N.H.E.

ISSN:0008-4042    

DOI:10.1139/v61-295

出版商:NRC Research Press    

年代:1961

数据来源: NRC