Synthesis of dimethylaminoethyl chitin and applications as a polymeric ligand to form Rh cluster complexes for the reduction of benzaldehyde and nitrobenzene

Abstract

A chitin containing dimethylaminoethylated group (DMAE-chitin) was prepared by the reaction of chitin with (dimethylamino)ethyl chloride in homogeneous or heterogeneous conditions. Compared with heterogeneous dimethylaminoethylation, DMAE-chitin with higher DS and more effectiveness for the desired reduction could be obtained homogeneously in the presence of sodium hydride under DMAc/LiCl solution. By the combination of suitable DMAE-chitin with Rh6(CO)16, benzaldehyde and nitrobenzene could be converted into correspondingly reductive products in high yields under the WGSR condition. Using the polymer-bound Rh cluster catalysts, the hydrogenation occurred in a triphase system, which made work-up procedures simple.