摘要:

The mechanism of oxidation of thetrans-isomer of decahydronaphthalene (trans-decalin) by gaseous oxygen at 100 °C. has been studied. The rate of retention of oxygen by decalin and the rates of formation of three volatile oxidation products were measured over the first 100 to 200 hr. of the oxidation reaction. The rate of retention of oxygen has been found to be independent of the oxygen concentration in the oxidizing gases but to depend on decalin concentration to the three-halves power. The rates of formation of the volatile oxidation products are also independent of oxygen concentration but are proportional to the decalin concentration. The activation energies of each of the reactions were determined. An initiating reaction forming carbon monoxide and hydrogen has been postulated based on the ratio of the rates of formation of the volatile compounds in the inhibited period of oxidation. Some data on the mechanism of the oxidation reaction in the accelerated period have also been obtained.

ISSN:1923-4287    

DOI:10.1139/cjr49b-006

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr49b-007

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Palladium may be precipitated quantitatively with 1,10-phenanthroline from palladous chloride solutions; variations in the hydrochloric acid concentration from 1 to 20% had no effect on the precipitation. The reagent yields no precipitates with other platinum metals under similar conditions; slightly high results, however, were obtained when palladium was precipitated from solutions containing these metals. The precipitate has the composition C12H8N2PdCl2and may be used as a weighing form for palladium. A micro-volumetric method for palladium using 1,10-phenanthroline is described. Small amounts of platinum (as Pt+4) do not interfere.

ISSN:1923-4287    

DOI:10.1139/cjr49b-008

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Rhodium may be precipitated quantitatively with 2-mercaptobenzoxazole or 2-mercaptobenzothiazole. An acetic acid precipitating medium is preferred; slight variations in the concentration of acid, when nitric acid was used, caused low results. Several similar type organic compounds showed no advantages over the above two. The complex appears to have three molecular weights of the reagent combined with one atomic weight of rhodium.

ISSN:1923-4287    

DOI:10.1139/cjr49b-009

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

In highly colored soil extracts, it was found impossible to determine nitrates directly by the phenoldisulphonic acid color reaction. Attempts to remove the coloring matter by oxidation or absorption were not successful. The most satisfactory method was found to be reduction of the nitrate to ammonia with Devarda's alloy in 0.1 Nsodium hydroxide solution in the cold after the removal by steam distillation, of any ammonia that might be present in the extract. The ammonia formed from the nitrate was steam distilled into 0.01 Nhydrochloric acid solution and determined colorimetrically by Nessler's reagent using a Klett–Summerson photoelectric colorimeter. The recovery of nitrates from the colored solutions and from standards was satisfactory. The aliquot taken for the determination should contain not more than 0.125 mgm. nitrogen as nitrate.

ISSN:1923-4287    

DOI:10.1139/cjr49b-010

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The following compounds have been prepared labeled with C14: cyanamide, urea, thiourea, dicyandiamide, and guanidine nitrate. Cyanamide was synthesized by heating radioactive barium carbonate at 850 °C. in a stream of ammonia and extracting with water the barium cyanamide so formed. Urea and thiourea were prepared from cyanamide by hydrolysis under suitable conditions. When an aqueous solution of cyanamide was heated, its dimer, dicyandiamide, was obtained and the latter compound was converted to guanidine nitrate by fusing with ammonium nitrate at 175° to 185 °C. The preparations of the above materials were carried out on a 5 to 10 millimole scale, and good yields were obtained in each case.

ISSN:1923-4287    

DOI:10.1139/cjr49b-011

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The isopiestic method has been applied to the sorption of carbon tetrachloride and water vapors by activated coconut shell charcoals. The isopiestic charges were found to be linearly related over wide pressure ranges. Isotherms formed by plotting the isopiestic charges of two charcoals one against the other consisted of three linear sections for both carbon tetrachloride and water. If the pressure isotherm of one charcoal be known, those of other charcoals may be computed from it by weighing relatively few isopiestic charges. Errors inherent in the measurement of equilibrium pressures, as well as those caused by the drift of the pressure isotherms towards higher sorption capacities at a given pressure, are eliminated in the isopiestic method of comparing charcoals. The linear relation between the isopiestic charges affords a simple criterion of rejection for equations proposed to fit the pressure isotherms. It also throws into relief the structural regularities in activated charcoals. The existence of discontinuities m the sorption process, reported by previous experimenters, is supported by the isopiestic data.

ISSN:1923-4287    

DOI:10.1139/cjr49b-012

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The isopiestic method was used to study the sorption of carbon tetrachloride, water, methanol, and toluene by a series of charcoals representing the same coconut shell source at different stages of steam activation. The sorption of water by two charcoals of this series impregnated with benzoic acid was similarly investigated. The isopiestic charges of this activation series of charcoals were linearly related over wider pressure ranges than were those of unrelated charcoals. The activation process was found to be connected primarily with the principal pressure range over which single straight lines were obtained on plotting the isopiestic charges one against the other. The isopiestic data presented the following picture of charcoal activation. The activation process has created surfaces, probably of a heterogeneous character, which are active to all the four vapors studied. At any stage of activation these surfaces take up proportionate quantities, but not equal liquid volumes, of each sorbate at saturation pressure. The various types of surfaces increase in abundance with activation at the same relative rate, so that they are always present in the charcoal in the same relative proportions, up to a certain stage of activation. At this stage the production of the surfaces active at relatively low pressures begins to decline. This indicates that new pores are being created more slowly in comparison with the widening of existing pores. In addition to the active surfaces just described, the activation process produces some chemically selective centers which are active at minute relative pressures. The water sorption data discredit the theory of capillary condensation.

ISSN:1923-4287    

DOI:10.1139/cjr49b-013

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Theoretical treatments of the elastic and swelling properties of three-dimensional polymers are reviewed and the predicted influence of network structure discussed. An expression is obtained for the statistically most probable distribution of molecular weight for polymers terminated by chain transfer with a modifier. Depletion of modifier does not lead to a large increase in molecular heterogeneity. The formation of an insoluble fraction and the development of cyclic structures when such polymers are subjected to cross-linking conditions are treated by an application of the theory of gelation.

ISSN:1923-4287    

DOI:10.1139/cjr49b-014

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Addition of potassium persulphate to a latex leads to cross-linking with typical diene polymers but has little effect on polystyrene. The rate of cross-linking is directly proportional to the persulphate concentration. The activation energy is 26,900 cal. The rate depends on latex particle size and is affected by the presence of other reagents. The course of gelation supports the predictions of the statistical theory of random cross-linking.

ISSN:1923-4287    

DOI:10.1139/cjr49b-015

出版商:NRC Research Press    

年代:1949

数据来源: NRC