Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene
Univalent Gallium Salts of Weakly Coordinating Anions: Effective Initiators/Catalysts for the Synthesis of Highly Reactive Polyisobutylene
复制标题
DOI：
10.1021/om4005516
复制
发表时间：
2013-11-25
期刊：
影响因子：
2.8
通讯作者：
Krossing, Ingo
中科院分区：
文献类型：
--
作者：
Lichtenthaler, Martin R.;Higelin, Alexander;Krossing, Ingo
本文讨论了一价镓盐[Ga-（C6 H5 F）（2）]（+）[Al（ORF）（4）]（-）和新的完全表征的[Ga（1，3，5-Me3C6H3）（2）]（+）[Al（ORF）（4）]（-）（R-F = C（CF 3）（3））在引发或催化合成高活性聚（2-甲基丙烯）-高反应性聚异丁烯（HR-PIB）-在几种溶剂中。一系列的聚合反应证明了一价镓盐用于异丁烯聚合的高效率和高质量。使用非常低浓度的[Ga（C6 H5 F）（2）]（+）[Al（ORF）（4）]（-）（低至0.007摩尔%），同时在高达+/- 0摄氏度的反应温度下和在非致癌性和非水危害性溶剂甲苯中工作，获得了最佳结果。在这些条件下，以良好的产率获得了末端烯属双键的α含量高达91摩尔%且分子量为1000-2000的HR-PIB。当将[Ga（C6 H5 F）（2）]（+）[Al（ORF）（4）]（-）改变为更富电子的[Ga（1，3，5-Me 3C 6 H3）（2）]（+）[Al-（ORF）（4）]（-）时，聚合温度可升高至+10 ℃。因此，镓（I）阳离子的反应性似乎可以通过配体交换反应来调节。实验结果，密度泛函理论计算和质谱研究指向一个协调聚合机制。
The scope of the univalent gallium salts [Ga-(C6H5F)(2)](+)[Al(ORF)(4)](-) and the new completely characterized [Ga(1,3,5-Me3C6H3)(2)](+)[Al(ORF)(4)](-) (R-F = C(CF3)(3)) was investigated in terms of initiating or catalyzing the synthesis of highly reactive poly(2-methylpropylene)-highly reactive polyisobutylene (HR-PIB)-in several solvents. A series of polymerization reactions proved the high efficiency and quality of the univalent gallium salts for the polymerization of isobutylene. The best results were obtained using very low concentrations of [Ga(C6H5F)(2)](+)[Al(ORF)(4)](-) (down to 0.007 mol%) while working at reaction temperatures of up to +/- 0 degrees C and in the noncarcinogenic and non-water hazardous solvent toluene. Under these conditions, HR-PIB with an alpha-content of terminal olefinic double bonds up to 91 mol% and a molecular weight of 1000-2000 was obtained in good yields. Upon changing [Ga(C6H5F)(2)](+)[Al(ORF)(4)](-) for the electron richer [Ga(1,3,5-Me3C6H3)(2)](+)[Al-(ORF)(4)](-), polymerization temperatures could be increased to +10 degrees C. The reactivity of the gallium(I) cations therefore seems to be tunable through ligand exchange reactions. Experimental results, density functional theory calculations, and mass spectrometric investigations point toward a coordinative polymerization mechanism.