物理化学学报 >> 1990, Vol. 6 >> Issue (03): 298-302.doi: 10.3866/PKU.WHXB19900309

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乙醇-苯乙烯体系的辐解及α-羟乙基自由基反应动力学

张旭家; 吴季兰; 哈鸿飞   

  1. 北京大学技术物理系
  • 收稿日期:1988-09-21 修回日期:1989-04-01 发布日期:1990-06-15
  • 通讯作者: 张旭家

The Kinetics of α-Hydroxyethyl Radical in the Radiolysis of Ethanol-Styrene System

Zhang Xu-Jia; Wu Ji-Lan; Ha Hong-Fei   

  1. Department of Technical Physics, Peking University
  • Received:1988-09-21 Revised:1989-04-01 Published:1990-06-15
  • Contact: Zhang Xu-Ji

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摘要： γ射线辐照乙醇, 通过苯乙烯抑制其辐解产物的研究, 证明在乙醇介质中α-羟乙基自由基只进行重合反应, 而无歧化反应; 苯乙烯可与α-羟乙基自由基反应, 其竞争反应为
Sl+CH_3 CHOH→P
2CH_3CHOH→(CH_3CHOH)_2
求得动力学方程为
G'=G_0 k_6/2(k_7) 1/2 (G'/Dk')[Sl]
G_0为纯乙醇γ射线辐照时2、3-丁二醇的产额, G_0=2.1, k_6/(k7)~(1/2)=0.53. 假定k_7为扩散反应速率常数, 则α-羟乙基自由基与丰乙烯加成反应的速率常数为k_6=4.0×10~4 L·mol~(-1)·s~(-1).

Abstract: The variations of the G value of the major products (H_2, CH_3CHO, (CH_3CHOH)_2) of the γ-radiolysis of liquid ethanol with the dose absorbed by the ethanol have been measured.
The kineties of α-hydroxyethyl radical reacted with styrene in the ethanol-styrene system has been investigated.
St+CH_3CHOH→P
2CH_3CHOH→(CH_3CHOH)_2
The kinetic equation has been derived as
G'=G_0 k_6/2(k_7) 1/2 (G'/Dk')[Sl]
and we got K_6=4.0×10~4 L·mol~(-1)·s~(-1).
The disproportionation of α-hydroxyethyl radical scarcely occurs and acetaldehyde may come from the fast processes in spur.