碳酸钾在吡嗪类钴配合物对氯苄双羰化反应中的助催化作用

The Cocatalytic Effects of K_2CO_3 on the Double Carbonylation of Benzyl Chloride

探讨了碳酸钾对氯苄双羰化反应的影响,发现氯化钴/碳酸钾对氯苄的双羰化反应有一定的助催化作用。实验结果表明,氯化钴/吡嗪2,3 二羧酸钾体系对氯苄没有催化活性。在没有配体存在的情况下,仅有氯化钴时氯苄也不发生任何反应;加入碳酸钾后,苯丙酮酸(PPA)产率为8.8%;再加入吡嗪2,3 二羧酸钾(KPzdc)后,PPA产率增加到26.7%。当配体改为吡嗪2 羧酸钾(KPzca)时,双羰化产物为β苄基α苯丙酮酸(BPPA),K2CO3的加入并不呈现特有的催化活性,相反,加入量太多时会降低BPPA的产率。从理论上对实验结果进行了解释。

The influence of K_2CO_3 on the double carbonylation of benzyl chloride was investigated. CoCl_2 and potassium pyrazine-2,3-dicarboxylate(KPzdc) catalytic system hadn't catalytic activity to the carbonylation of benzyl chloride. Without any ligand, CoCl_2 hadn't also catalytic activity. But CoCl_2 /K_2CO_3 was discovered to have definite catalytic ability for the double carbonylation of benzyl chloride and product was phenylpyruvic acid (PPA) with yield 8.8%, furthermore, after the ligand of KPzdc was superadded, the PPA yield increased to 26.7%. If the superadded ligand was potassium pyrazine-2-carboxylate(KPzca), the product was β-benzyl-α-phenylpyruvic acid (BPPA). To CoCl_2 /Kpzca catalytic system, K_2CO_3 could not increase catalytic activity, contrarily superfluous K_2CO_3 decreased BPPA yield. These experimental results are explained on theory.