摘要:

The heats of wetting by water of cotton cellulose containing various amounts of adsorbed and desorbed water were measured. These measurements together with those of the water vapor sorption isotherm were used to calculate the integral and differential enthalpies, free energies, and entropies of adsorption. Irreversible effects were avoided by vacuum-drying all samples at room temperature. The differential enthalpy values suggest hydrogen bonding. The differential entropies are explained in terms of changes in both the adsorbate and adsorbent.The surface area of the cellulose is calculated by applying the Brunauer–Emmett–Teller and Harkins–Jura equations to the adsorption isotherm. The changes in the differential enthalpies and entropies of adsorption follow the same sequence as the changes in film formation given by the surface area calculations.No hysteresis was observed in the heats of wetting of adsorbed and desorbed samples. It is concluded that the hysteresis of the sorption isotherm is an entropy phenomenon. This supports Barkas' explanation of hysteresis in terms of plastic deformation of a gel.

ISSN:0008-4042    

DOI:10.1139/v59-202

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Pyrrole and alkyl pyrroles react spontaneously with phenyl isothiocyanate to produce C-substituted derivatives. The structures of the products are confirmed by physical methods. The reaction is catalyzed by organic bases.

ISSN:0008-4042    

DOI:10.1139/v59-203

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The density and electrical conductivity of the systems AgNO3–Ba(NO3)2, –Ca(NO3)2, and –Mg(NO3)2have been determined from 210 to 320° and from 0 to 20 equiv. %. The addition of magnesium nitrate causes the greatest shrinkage of the equivalent volume and reduction of the conductivity, barium nitrate the least.The low conductivity of the binary melts is explained in terms of a mechanism involving restricted jumps and variation of the energy barrier with temperature and kind of ion added.

ISSN:0008-4042    

DOI:10.1139/v59-204

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The N.M.R. spectra of the triphenylmethyl cation and several of its derivatives substituted with methyl, methoxyl, andtert-butyl groups in the meta or para position have been obtained in trifluoroacetic acid – trifluoroacetic anhydride solution. The ring protons and substituent protons are all shifted to lower fields, i.e. are less shielded in the carbonium ions than in the neutral compounds of similar structure. The chemical shifts for the substituent protons are greater for para than for meta substituents and for mono- rather than tri-substituted ions. With each ion only a single peak was observed for the substituent protons but the ring protons were, in some cases, well resolved. The theoretical implications of these results are discussed.

ISSN:0008-4042    

DOI:10.1139/v59-205

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The above system is a further stage in the study of the five-component system, containing the radicals Li2, Na2, K2, Cl2, SO4, and water. The double salts occurring are Li2SO4•K2SO4and 3K2SO4•Na2SO4: no ternary salt is formed.

ISSN:0008-4042    

DOI:10.1139/v59-206

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The reaction of sulphuryl chloride with methyl α-D-glucopyranoside, methyl 4,6-O-benzylidene-α-D-glucoside, methyl β-D-arabinopyranoside,D-mannitol, 2,5-O-methylene-D-mannitol, dulcitol, and sucrose is described.

ISSN:0008-4042    

DOI:10.1139/v59-207

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Reactions of butene-1, isobutene, 3-methyl butene-1, and 2-methyl butene-2 on ZnO catalysts have been investigated at 615°. The formation of the observed products is discussed in terms of a sequence of surface processes incorporating dissociation of the bonds in β position to the double bond, with formation of chemisorbed allyl and substituted allyl radicals.

ISSN:0008-4042    

DOI:10.1139/v59-208

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

It has now been shown that an earlier assignment of configuration in which 1,4-↑↑-ethylene-Δ5-cyclohexenedicarboxylic acids and their derivatives were presumed to form with mercuric salts 5-↓-hydroxy-6-↓-anionomercuri-1,4-↑↑-ethylenecyclohexanedicarboxylic acid derivatives is incorrect. Instead 5-↓-hydroxy-6-↑-anionomercuri-1,4-↑↑-ethylenecyclohexanedicarboxylic acid derivatives are formed, similarly with the homologous 5-↓-hydroxy-6-↑-anionomercuri-1,4-methylenecyclohexane-2,3-dicarboxylic acid derivatives. This similarity is exemplified by comparable dipole moments. The exception is 5-↓-hydroxy-6-↓-chloromercuri-1,4-↑↑-methylenecyclohexane-2,3-↓↓-dicarboxylic acid, γ-lactone, which has a configuration opposite to all of the others of these series having boat-type cyclohexane ring conformations. The exception is attributed to steric effects.

ISSN:0008-4042    

DOI:10.1139/v59-209

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A further study has been made of the reaction of Hg2026(3P1) atoms, in natural mercury vapor (HgN), with hydrogen chloride under flow conditions at room temperature. Emphasis has been placed in this study on the effect of reaction parameters and mercury-recovery techniques on the Hg202content of the solid calomel formed in the reaction.For pure hydrogen chloride the Hg202content of the calomel was found to be 39.9 ± 0.3%, compared to the natural abundance of 29.8%. With 20–40 mole % of butadiene-1,3 in the hydrogen chloride, calomels containing 83–84% of Hg202were consistently obtained.The isotopically specific aspects of the reaction in pure hydrogen chloride can be adequately explained by the sequence:where M in reaction [3] is a third body or the wall. From the Hg202-abundance data and steady-state considerations, it has been shown that the ratio of partitioning of the absorbed radiation to [1] and [2], respectively, = Φ1/Φ2 = 0.40 ± 0.02. In short, 29% of the primary reaction proceeds by the isotopically specific step [1].The Hg202content of the calomel product was found to increase markedly when unsaturated hydrocarbons were added to the hydrogen chloride stream. The addends studied included butadiene-1,3, benzene, isoprene, acetylene, propylene, and ethylene in order of decreasing effectiveness. In the presence of the unsaturated addend (U) two additional reactions were postulated to occur:From steady-state calculations the effectiveness of the addend can be shown to be determined by the rate ratio,k8/k4.For the maximally enriching mixture of hydrogen chloride and butadiene, the effect of variations in lamp temperature and reaction pressure was studied. At lamp temperatures exceeding approximately 35 °C, reduced enrichments were obtained owing to emission-line broadening. A progressive reduction in enrichment was also observed with substrate pressures greater than 25 mm, owing presumably to Lorentz-broadening of the hyperfine absorption contours of the HgNin the reaction cell.The Hg202content of the calomel product was determined by resonance radiation absorbiometry. The apparent Hg202abundances of the mercury recovered from the calomel product were found to depend strongly on the method used for isolating the enriched mercury from the calomel. Evidence was obtained for the occurrence of isotopically degradative exchange reactions during the recovery process. A recovery technique was developed which appeared to eliminate this exchange degradation.

ISSN:0008-4042    

DOI:10.1139/v59-210

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The electronic and infrared absorption spectra of thelephoric acid and its leucoacetate indicate that the structure at present accepted for the pigment is incorrect. It is suggested from an interpretation of these spectra, together with a re-evaluation of the reported properties of thelephoric acid and its derivatives, that the substance may be a hydroxylated terphenyl containing internal quinhydrone and benzofuran systems (e.g. (V)).

ISSN:0008-4042    

DOI:10.1139/v59-211

出版商:NRC Research Press    

年代:1959

数据来源: NRC