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1.通过吸氧及过氧化物的形成,证明分子氧氧化三乙基硼在30°时(庚烷中)所得过氧化产物为二过氧化乙基硼酸二乙酯(II)及一过氧化乙基硼酸二乙酯(III)的混合物(简称为“二过氧化物”);而在-70°时,首次证明,氧化停留在过氧化二乙基硼酸乙酯(I)阶段.升温时,I继续被氧化为“二过氧化物”.2.30°氧化所得“二过氧化物”和-70°所得一过氧化物,在热稳定性及分解机理上有下列不同:(i)30°氧化产物的热稳定性远高于-70°氧化产物;例如,在45°及相似浓度下,前者的半衰期为三、四日以上,而后者的半衰期不到半小时.(ii)30°氧化产物的起始分解,表观上按二级反应进行,从不同温度(45°,55°,65°,82°)下的分解速度常数求得分解活化能为21千卡/克分子;-70°氧化产物则在表观上按一级反应进行分解,从不同温度(0°,22°,32°,45°)下分解速度常数的Arrhenius关系求得分解活化能为12千卡/克分子.(iii)30°氧化产物的分解不是按自由基历程进行的,表现为分解过程中不消耗碘,受酸及碱的催化,而且不引发醋酸乙烯酯的聚合.-70°氧化产物的分解则系按自由基历程进行,在45°及室温下均引发醋酸乙烯酯的聚合.3.30°及-70°氧化产物的主要分解产物分别为硼酸三乙酯及乙基硼酸二乙酯(分别作为乙醇胺络合物V及VI分离鉴定),因此支持在该不同温度下所形成的过氧化物分别为“II加III”及I.4.由于在低温下吸氧截然停止在一过氧化物阶段,以及吸氧结果的重复性,可以考虑将低温氧化作为分析烷基硼纯度的方法之一.
1. Through the formation of oxygen and peroxide, molecular oxidation of triethylboron at 30 ° (heptane) obtained peroxide product is diethyl peroxydicarbonate (II) and a peroxidation (Abbreviated as “diperoxide”) of ethyl diethyl borate (III); while at -70 °, it was first demonstrated that oxidation stayed in the stage of ethyl peroxyethyl ethyl borate (I). I continues to be oxidized to “diperoxide ” at the time of warming. 2.30 ° oxidation results in “diperoxide” and -70 ° resulting in a peroxide with the following differences in thermal stability and decomposition mechanism : (i) The thermal stability of the 30 ° oxidation product is much higher than that of the -70 ° oxidation product; for example, the half-life of the former is three or four days at 45 ° and similar concentrations, whereas the half-life of the latter is less than half an hour. (ii) The initial decomposition of the 30 ° oxidation product was visually followed by a secondary reaction. The decomposition activation energy was found to be 21 kD from the decomposition rate constants at different temperatures (45 °, 55 °, 65 °, 82 °) Calorie / mol molecules; the -70 ° oxidation products decompose apparently according to the first order reaction, and the decomposition activation energy can be obtained from the Arrhenius relation of the decomposition rate constant under different temperatures (0 °, 22 °, 32 °, 45 °) For 12 kcal / gram points (Iii) The decomposition of the 30 ° oxidation product is not carried out on a free radical basis, as shown by the fact that no iodine is consumed during the decomposition, catalyzed by acids and bases, and no polymerization of vinyl acetate is initiated. Decomposition is based on the free radical course, at 45 ° and at room temperature all trigger the polymerization of vinyl acetate 3.30 ° and -70 ° oxidation products of the main decomposition products were triethyl borate and ethyl ethyl borate As ethanolamine complexes V and VI separation and identification), thus supporting the formation of the peroxide at different temperatures were “II plus III ” and I.4. As oxygen at low temperatures stopped overnight Oxide stage, and oxygen repeatability results, consider the use of low temperature oxidation as one of the methods for analyzing the purity of alkylboron.