分光光度法研究二羟基二过碘酸合镍(Ⅳ)氧化三乙醇胺的反应动力学及机理  

Kinetics and Mechanism of Oxidation of Triethanolamine by Diperiodatonickelate(Ⅳ) Ion in Aqueous Medium

作　　者：单金缓[1] 魏海英[1] 王莉[1] 申世刚[1] 刘保生[1] 孙汉文[1] 王安周[1] 

机构地区：[1]河北大学化学与环境科学学院,保定071002

出　　处：《高等学校化学学报》2002年第10期1860-1863,共4页Chemical Journal of Chinese Universities

基　　金：河北省自然科学基金 (批准号 :2 95 0 66)资助

摘　　要：在碱性介质中 ,用分光光度法研究了二羟基二过碘酸合镍 ( )配离子氧化三乙醇胺的动力学 .结果表明 ,反应对 Ni( )为准一级反应 ,速率常数 kobs=(k1 +k2 [OH- ]) K1 K2 [OH- ][TEA]/{[H2 IO3- 6 ]+K1[OH- ]+K1 K2 [OH- ][TEA]},对还原剂三乙醇胺为正非整数级 ,表观速率常数随 [OH- ]的增加而增加 ,随[IO- 4]的增加而减小 .据此提出了 Ni( )和还原剂所形成的活化配合物的内部电子转移的反应机理 .并求得2 8℃时前期平衡常数和速控步骤的速率常数分别为 K1 =2 .0 63 ,K2 =3 6.471 L· mol- 1 ;k1 =8.0 0 8× 1 0 - 2s- 1 ,k2 =0 .2 896mol- 1 · L· s- 1 .The kinetics of oxidation of triethanolamine by dihydroxydiperiodatonickelate(Ⅳ) ion(DPN) was studied by spectrophotometry in aqueous medium. The reaction was found to be pseudo-first order with respect to Ni(Ⅳ) and to be fractional order with respect to triethanolamine. The rate increased with the increase of the concentration of OH - and decreased with the increase of the concentration of IO - 4. The observed rate constants: k obs=(k 1+k 2)K 1K 2/{[H 2IO 3- 6]+K 1+K 1K 2}. Based on these, a mechanism involving the form of activative complex between Ni(Ⅳ) and reduct(TEA) was proposed. In addition, we calculated the equilibrium constants and rate-determining constants at 28 ℃, which were k 1=8 008×10 -2 s -1, k 2=0 289 6 mol -1·L·s -1, K 1=2 063 and K 2=36 471 L·mol -1.

关 键 词：分光光度法 二羟基二过碘酸合镍(Ⅳ) 三乙醇胺 氧化还原 动力学 配合物 反应机理 

分 类 号：O614.813[理学—无机化学] O643.1[理学—化学]