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进行了过氧化月桂酰(1)在脱氧的苯中的分解动力学研究,当起始浓度0.1～0.2克分子·升~(-1),温度30℃、40℃时,1不是严格地按一级反应分解的。在50℃下起始浓度0.04～0.34克分子·升~(-1)时,实验结果符合一级加二分之三级的反应规律:-(da/dt)=k_1a+k_1a~(3/2)。求出的自发分解速率常数k_1=0.0115小时~(-1),诱导分解速率常数k_1=0.014克分子~(-1.2)·升~(1/2)·小时~(-1)。研究了50℃时有自由基捕获剂galvinoxyl(2)的动力学试验,根据光密度变化测定分解反应,知1为一级,2为零级,诱导分解受到抑制。假定1的初级分解生成两个自由基,且可被2完全捕获,则计算出来的分解速率常数为0.00570小时~(-1),恰好为碘量法测定1的自发分解速率常数的一半;同时,根据有2存在下测出1分解产生的二氧化碳量,约为理论值(假定一个1分子分解产生两个二氧化碳分子)的一半的事实,推论1在50℃的苯中的初级分解可能有如下两种过程: (RCOO)_2→2RCOO·→R··OCOR+CO_2 或者(RCOO)_2→R·CO_2·OCOR→R··OCOR+CO_2生成的R·和RCOO·一部分在笼内反应(歧化、再结合等);一部分扩散到溶剂中,当有2存在时,为2所捕获。
Decomposition kinetics of lauroyl peroxide (1) in deoxygenated benzene was studied. When the initial concentration was 0.1-0.2 mol · L -1, the temperature was 30 ℃ and the temperature was 40 ℃, 1 was not strictly A reaction decomposition. At 50 ℃ initial concentration of 0.04 ~ 0.34 mol · L ~ (-1), the experimental results are in accordance with the first-order and second-third order reaction rules: - (da / dt) = k_1a + k_1a ~ 2). The constants of spontaneous decomposition k_1 = 0.0115 h -1 and induced decomposition rate constant k_1 = 0.014 m -1 ~ 1/2 h -1 were obtained. The kinetics of the free-radical scavenger galvinoxyl (2) at 50 ℃ was studied. The decomposition reaction was determined according to the change of optical density. The results showed that 1 was first order and 2 was zero order, and induced decomposition was inhibited. Assuming that the primary decomposition of 1 generates two free radicals and can be completely captured by 2, the calculated decomposition rate constant is 0.00570 h -1, which is exactly half of the spontaneous decomposition rate constant of I, , The fact that the initial decomposition of 1 in benzene at 50 ° C may be as follows from the fact that the amount of carbon dioxide produced by 1 decomposition is measured in the presence of 2 is about one half of the theoretical value (assuming that one molecule decomposes to produce two carbon dioxide molecules) Two processes: (RCOO) _2 → 2RCOO → R ·· OCOR + CO_2 or (RCOO) _2 → R · CO_2 · OCOR → R ··· Some of R · and RCOO · generated by OCOR + CO_2 react in the cage , Recombination, etc.); some diffuse into the solvent, and when 2 is present, 2 are trapped.