Synthesis of novel bipyridyl ligands and application in preparation of polyketone

摘要

In this article, novel 2,2′-bipyridyl derivatives were synthesized and the excellent bipyridyl ligands were chosen as catalyst to apply in the copolymerization of carbon monoxide (CO) and styrene (ST) to prepare polyketone. 4,4′-Dicarboxyl-2,2′-bipyridine(4,4′-dcpy) was synthesized by use of synthesized 4,4′-dimethyl-2,2′-bipyridine(4,4′-dmpy). The products (4,4′-dmpy and 4,4′-dcpy) were characterized by melting point, NMR, IR, GC-MS, and elemental analysis. The effects of different ligands and various reaction conditions incuding the usage of ligand, p-toluenesulfonic acid, solvent, p-benzoquinone, the CO pressure, and reaction temperature on catalytic activity of the copolymerization were investigated. The catalytic activity of 4,4′-dmpy, 4,4′-dcpy and 2,2′-bipyridine were compared. The results showed that the addition of the electron-donating substituent can enhance catalytic activity, with the sequence as follows: 4,4′- dimethyl-2,2′-bipyridine > 2,2′-bipyridine > 4, 4′-carboxy 2,2′- bipyridine.