摘要:

Insolation of carbon tetrachloride solutions of chlorine dioxide initiates a thermal decomposition, the magnitude of which may exceed that for the photoreaction with low light intensity. This thermal decomposition is inhibited by keeping the solutions at 3 °C. or by adding water.In contradiction to the findings of other investigators, it is found that chlorine and oxygen are not the only products of photodecomposition. As products of the photodecomposition of chlorine dioxide at the wave-lengths 3650 and 4360 Å, the oxides Cl2O, Cl2O6, and Cl2O7as well as chlorine and oxygen appear. The quantum efficiency at λ 3650 Å is 2, and at 4360 Å, 1.In the unsensitized decomposition, concentration effects are observed which are greatly decreased when the solutions are stirred.In the bromine sensitized decomposition with 5460 Å, there is less chlorine monoxide but relatively as much Cl2O6and Cl2O7formed as in the unsensitized reaction.In the sensitized decomposition the quantum yield is independent of the concentration of chlorine dioxide, but depends on the light intensity. The observed quantum yield for the sensitized reaction is 0.2 to 0.3.Mechanisms for the photo-reactions have been proposed.

ISSN:1923-4287    

DOI:10.1139/cjr37b-054

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Passage of a glow discharge through oxygen at a pressure of 25 mm. of mercury and 17,000 volts apparently produces no ozone. The non-production of ozone is due to deozonization at the electrodes. A discharge tube is described that can be used for the demonstration and quantitative investigation of the formation of ozone in a glow discharge.

ISSN:1923-4287    

DOI:10.1139/cjr37b-055

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

A new absorbing chamber, which adapts the methoxyl analysis more conveniently to the Vieböck procedure, is described for the micromethoxyl apparatus. This receiver acts by hindering the gas flow so as to facilitate absorption of methyl iodide.

ISSN:1923-4287    

DOI:10.1139/cjr37b-056

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

A demethylated spruce lignin suitable for further study has been obtained by treating methylated methanol lignin with hydriodic acid. This treatment removes the aliphatic hydroxyl, and leaves 6.9 aromatic and 0.6 carboxylic hydroxyl groups per kg. On the basis of the phenolic content it is estimated that the maximum aromatic content of spruce lignin is about 40 to 45%.

ISSN:1923-4287    

DOI:10.1139/cjr37b-057

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The delignification of wood by means of sodium, potassium, and lithium hydroxides has been determined with alkaline concentrations from 1.4 to 14.3 molar, and at temperatures from 120° to 180 °C. A small-scale experimental technique was used by means of which the time, temperature, and concentration variables could be closely controlled.It was found that delignification increased with concentration. A 2.9 Msolution reacted about twice as fast as a 1.4 Msolution of sodium hydroxide at 160 °C. The difference in rate of reaction is less for solutions of concentrations of 2.9 and 4.5 M. Potassium hydroxide of 1.4 Mconcentration reacts only slightly more readily than sodium hydroxide of the same concentration, but the difference in reaction rate becomes more marked with increase in concentration. Lithium hydroxide reacts much more slowly than either of the other two hydroxides. There is a marked increase in reaction rate with increase in temperature. A ten degree rise in temperature somewhat more than doubles the rate of delignification. The rate of reaction is considerably diminished by the presence of sodium chloride or of reaction products in the cooking liquor.

ISSN:1923-4287    

DOI:10.1139/cjr37b-058

出版商:NRC Research Press    

年代:1937

数据来源: NRC