三甲基铝的合成

用新的催化体系(铁-锑复合催化剂)催化三乙基铝(TEA)与溴甲烷进行烷基交换反应合成三甲基铝(TMA)。研究了 SbCl3含量、铁-锑复合催化剂中FeCl3与SbCl3的摩尔比、反应温度、溶剂癸烷含量和TEA的滴加时间对TEA转化率的影响。实验结果表明,该铁-锑复合催化剂催化TEA与溴甲烷反应合成TMA的工艺是有效的;在n(SbCl3):n(TEA)=7:100、铁-锑复合催化剂中n(FeCl3):n(SbCl3)=3:100、n(癸烷):n(TEA)=4:10、反应温度105℃、TEA的滴加时间150 min和反应压力 0．1 MPa的最佳反应条件下,TEA的转化率达到92．8％;TMA收率达到64．3％,纯度为98．1％。该铁-锑复合催化剂具有反应选择性高、制备成本较低、易与产物分离的特点。

Synthesis of Trimethylaluminum

Trimethylaluminum(TMA),usually used in organic catalysis and organic synthesis,was synthesized by reaction of triethylaluminium (TEA) with methyl bromide on iron-stibonium complex catalyst. Influence of SbCl3 content in TEA,mole ratio of FeCl3 to SbCl3,amount of solvent(decane), reaction temperature and feeding time of TEA on reaction were studied. The catalyst added was efficient for alkyl exchange reaction. Under optimal reaction conditions: n (SbCl3) : n(TEA)=7 :100, n(FeCl3) :n(SbCl3) =3 : 100,reaction temperature 105℃,n(decane) : n(TEA) =4 : 10,feeding time of TEA 150 min and reaction pressure 0.1 MPa, conversion of TEA and yield of TMA could reach 92.8% and 64. 3% respectively. Purity of TMA was up to 98. 1%. The complex catalyst possessed high selectivity to TMA and low preparation cost, and could be easily separated from the product.