摘要:

The causes of hysteresis in the adsorption isotherms on porous Vycor glass are discussed, employing as ancillary evidence the dimensional changes of the adsorbent. Diagrams of domain complexions for pores of the ink-bottle type are given and used to develop certain of Everett's theorems. Evidence showing the interdependence of domains or voids is given. The compressibility of the porous adsorbent is evaluated and shown to differ with different adsorbates, which suggests distributions of adsorbed matter specific to the adsorbate. A thermodynamic development is given, which indicates that the most stable states of the system are represented along the adsorption isotherm. Finally, certain anomalous findings in the region of low adsorption and within the hysteresis loop are reported and discussed.

ISSN:0008-4042    

DOI:10.1139/v57-106

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The malonic ester synthesis of nervonic acid (tetracos-15-enoic acid) has been modified so that the product consists of purecisrather than a mixture ofcisandtransisomers. The modified synthesis has been used for the preparation of C14-labelled erucic and nervonic acids.

ISSN:0008-4042    

DOI:10.1139/v57-107

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Anhydrous and hydrated crystals of sodium and lithium permanganates have been irradiated with neutrons. After irradiation, the crystals were subjected to hydration and dehydration, and the effect of this treatment on the retention of radioactive manganese in the form of the permanganate ion was determined. Hydration of irradiated anhydrous sodium and lithium permanganates decreases the retention observed when the solids are dissolved in basic solutions. Dehydration of the irradiated trihydrate causes little change in the observed retention for sodium permanganate, but a pronounced decrease for lithium permanganate. The significance of the results is discussed.

ISSN:0008-4042    

DOI:10.1139/v57-108

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

In an attempt to prove that reduction can take place by hydride transfer, the conversion of triphenyl carbinol in formic acid to triphenylmethane via the carbonium ion was examined. Kinetic and isotopic proof was obtained for the following mechanism:The rate law based on the above mechanism iswhereR = C6H5, which leads to the integrated rate expressionThis equation was found to be obeyed under a variety of conditions.Anhydrous formic-dacid was synthesized in good yield by the glycerol catalyzed decomposition of oxalic acid-d2. The concentration of deuterium was shown by nuclear magnetic resonance spectroscopy to be greater than 99%. Use of this material in the reduction gave a kinetic isotope effect and led to isolation of triphenylmethane which had greater than 97% deuterium in the α-position, thus supporting the idea that a hydride ion was transferred from formate ion to the carbonium ion.The energy and entropy of activation for the rate controlling step have been found to be 18.3 kcal. per mole and −7.5 e.u. The negative ΔS‡ is presumably due to the less likely orientation for the transition state A as compared to B.

ISSN:0008-4042    

DOI:10.1139/v57-109

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The Hg(3P1) photosensitized decomposition of allene leads to the formation of a C3H3radical. The reaction of this radical with added methyl radicals shows it to have the propargyl (ĊH2—C≡CH) structure rather than the alternative allenyl (CH2=C=ĊH) structure. The dissociation of 1,2-butadiene proceeds by two modes, one to give H2 + C4H4, and the other a split into CH3and C3H3radicals. The dissociation of 1,3-butadiene leads to the same final products, a shift of a hydrogen atom being required for the split into free radicals. No evidence was found for a dissociation of 1,3-butadiene into two vinyl radicals. Considerable polymer formation occurred with all three compound

ISSN:0008-4042    

DOI:10.1139/v57-110

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A new crystalline seven-carbon branched-chain carbohydrate has been synthesized by application of the oxo reaction to 3,4,6-tri-O-acetyl-D-galactal. Periodate oxidation of the sugar alcohol was carried out to determine its structure. Crystalline benzoate andp-nitro-benzoate derivatives were obtained.

ISSN:0008-4042    

DOI:10.1139/v57-111

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Ultrafiltration of an aqueous solution of a synthetic mixture of inulin and clinical dextran has been used to separate the two polysaccharides. A clinical dextran has also been fractionated in the same way to yield five dextran fractions having number-average molecular weights ranging from 11,000 for the lowest to 190,000 for the highest fraction.

ISSN:0008-4042    

DOI:10.1139/v57-112

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Confirmation of the existence of aluminum trilaurate has been obtained by using infrared absorption to follow the course of the reactions of trimethylaluminum and aluminum isopropoxide with lauric acid. The trisoap is shown to exist as micelles of high molecular weight in solution, the size decreasing on dilution or elevation of temperature. On hydrolysis to the disoap, hydrogen bonding does not appear to play a significant role in the formation of polymer structures. Coordination of carboxylate groups with aluminum is shown to be a major feature of the structure of both tri- and di-soaps. Spectral assignments in the 6.0 to 6.4 μ region have been made for various types of inter- and intra-molecular coordination. The effects of dilution, hydrolysis, and hydrochlorination of aluminum trilaurate in solution have been assessed by viscosity, light-scattering, and infrared measurements.

ISSN:0008-4042    

DOI:10.1139/v57-113

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The S32–S34isotope exchange between sulphur dioxide and 100% sulphuric acid has been studied over the temperature range 200° to 400 °C. Equilibrium constants of 1.014, 1.011, and 1.008 at 205°, 300°, and 400 °C. respectively have been found, favoring the S34in the sulphuric acid. These results agree reasonably well with theoretical calculations made for the sulphur isotope exchange between sulphate ion and sulphur dioxide.

ISSN:0008-4042    

DOI:10.1139/v57-114

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The krypton photosensitized ionization of nitric oxide and acetone has been investigated. At constant nitric oxide pressure, the relation between ion current and krypton pressure is given byi = a + b(1 − e−cp), whereiis the ion current,a,b, andcare constants, andpis the krypton pressure. It has been further shown that the quenching cross section of nitric oxide for excited krypton is smaller than that of acetone. Sensitized photoionization was also obtained in the cases of xenon and anisole, and argon and nitric oxide. The quenching of excited krypton by helium, hydrogen, and deuterium has been studied. Helium quenches to a negligible extent; the quenching efficiency of hydrogen is rather greater than that of deuterium.

ISSN:0008-4042    

DOI:10.1139/v57-115

出版商:NRC Research Press    

年代:1957

数据来源: NRC