H+对离子液体催化的苯与乙烯烷基化的影响

在FeCl3／氯化丁基甲基咪唑离子液体中加入少量H^＋改性后，用于催化苯与乙烯的烷基化反应。结果表明，离子液体中加入H^＋改性后，乙烯的转化率由改性前的95．23％提高到100％，提高了4．77个百分点，乙苯的选择性由98．25％提高到99．42％。利用Raman光谱、FAB（快速原子轰击）和^1H NMR分析手段，对改性离子液体改善催化烷基化效果的原因进行了研究。结果表明，改性后离子液体中阴离子Fe2Cl7^-的强度下降，离子液体中加入H^＋后，形成超强酸，成为不同种类正碳离子的良好接受体，从而改善了H^＋传递反应的活性，使其具有较高的催化活性和选择性。

EFFECT OF PROTON ON THE ALKYLATION OF BENZENE WITH ETHYLENE USING IONIC LIQUID CATALYST

The alkylation of benzene with ethylene catalyzed by FeCl_3-bmimCl ionic liquid modified with proton (H~ ) was studied. The test results showed that after adding a small amount of H~ to FeCl_3-bmimCl ionic liquid the conversion of ethylene and the selectivity of ethylbenzene increased from 95.23% to 100%, and 98.25% to 99.42%, respectively. The structure and anions of ionic liquid before and after adding H~ were investigated by Raman spectrum, FAB and ~1HNMR. The results showed that after adding H~ the concentration of Fe_2Cl~-_7 decreased; super-acid formed in the ionic liquid had the static charge field that stabilized the carbonium ions, and improved the activity of hydrogen transfer reaction. Thus, the ionic liquid modified with H~ exhibited improved catalytic activity and selectivity.