巻号一覧
20 巻, 3 号
選択された号の論文の4件中1～4を表示しています
- |<
- <
- 1
- >
- >|
-
1977 年 20 巻 3 号 p. 198
発行日: 1977年
公開日: 2009/01/30
ジャーナル フリーPDF形式でダウンロード (50K) -
石渡 真理子, 矢作 宣男, 冨永 博夫1977 年 20 巻 3 号 p. 237-242
発行日: 1977/03/01
公開日: 2009/01/30
ジャーナル フリーKinetics and machanism were studied on the pyrolysis of n-propylbenzene in the presence of hydrogen with a flow reactor made of quartz. The reaction conditions were in the ranges of temperature from 500 to 650°C, of molar ratio of hydrogen to n-propylbenzene from 3 to 6, and of residence time from 2.5 to 8.5 sec at the atmospheric pressure. The main reaction products were styrene, methane, ethane, ethylene, toluene, ethylbenzene and benzene. Small amounts of the other several compounds were also identified by GC and GC/MS.
It was suggested that the reaction proceeds mainly by the free radical chain mechanism as follows, initiation: the dissociation of n-propylbenzene to benzyl and ethyl radicals, propagation: the formation of 1-phenylpropyl radical by hydrogen atom abstraction of n-propylbenzene, and its consecutive decompostion into styrene and methyl radical, termination: the recombination of methyl, ethyl and benzyl radicals. Methane, ethane and toluene are formed by the atom transfer of methyl, ethyl and benzyl radicals respectively with hydrogen, and ethylene by the hydrogen atom elimination of ethyl radical, etc. Benzene is believed to be formed by hydrogenolysis of n-propylbenzene in the same mechanism as that of toluene reported previously.抄録全体を表示PDF形式でダウンロード (438K) -
竹内 隆男, 長 孝, 柳井 弘, 長 哲郎1977 年 20 巻 3 号 p. 243-248
発行日: 1977/03/01
公開日: 2009/01/30
ジャーナル フリーA non-catalyzed thermal oxidation of pronionaldehyde, n-butylaldehyde, isobutylaldehyde and crotonaldehyde was carried out in the benzene solvent at 30°C, in order to clarify the initiation mechanism of the reaction in the steady state. The reaction may be initiated through the active radicals which are formed by the decomposition of aldehyde or the corresponding peracid obtained as an intermediate product. The rate constant of the radical formation from peracid was 90-1, 300 times as large as the one from aldehyde. Secondly, the formation rates of their radicals in the thermal oxidation were estimated from the concentrations of the peracid and aldehyde existing in the steady state. As a result it was clarified that the main mechanism in the initiation was the decomposition of peracid.
The apparent rate equation of the oxidation in the steady state was expressed as -d[O2]/dt=k[aldehyde]3/2 in a relatively high oxygen concentration. Judging from the experimental fact that the concentration of the peracids is proportional to that of the aldehydes, the real equation should be expressed as -d[O2]/dt=k'[peracid]1/2[aldehyde].抄録全体を表示PDF形式でダウンロード (436K) -
劉 懐徳, 河合 是, 山崎 康男1977 年 20 巻 3 号 p. 249-253
発行日: 1977/03/01
公開日: 2009/01/30
ジャーナル フリーStructures of Bi2O3-SnO2 catalysts consisting of various Bi/Sn atomic ratio were investigated by means of X-ray diffraction analysis. The binary mixture of Bi2O3-SnO2 was converted to Bi2Sn2O7, Bi2Sn2O7+α-Bi2O3, or Bi2Sn2O7+SnO2 according to their atomic ratio during calcination. Bi2Sn2O7 in these catalysts was converted to SnO2, γ-Bi2O3, and Bi12SnO20 during the course of toluene oxidation.
Catalytic activity of these catalysts for oxidative dehydrodimerization of toluene to bibenzyl and stilbene was determined in the temperature range 500-600°C using a conventional flow system with the fixed bed at the atmospheric pressure. A correlation between the catalytic activity and structures of these catalysts was made subsequently, combined with some reduction tests of these catalysts with toluene. It is suggested that Bi2Sn2O7 is the main active and selective component at 500°C, while α-Bi2O3, γ-Bi2O3, and Bi12SnO20 are active and selective at 600°C. The lattice oxygen combined with bismuth plays a role in the oxidation of toluene to dehydrodimer, and SnO2, as an oxygen-activating component, in the reoxidation of reduced bismuth.抄録全体を表示PDF形式でダウンロード (380K)
- |<
- <
- 1
- >
- >|