Dimethylaminoethylated hydroxypropyl-chitosan: Preparation and application as polymeric ligand to form Rh6 cluster complexes for the reduction of benzaldehyde and nitrobenzene

Abstract

Hydroxypropyl chitosan and its dimethylaminoethylated derivative were prepared in different conditions. Experimental results indicated that the degree of substitution (DS) of hydroxypropyl chitosan was strongly related to the molar ratio of propylene oxide to the glucosamine unit of chitosan, the used solvent, the reaction temperature and the amount of sodium hydroxide. Moreover, the obtained hydroxypropyl chitosan could be effectively dimethylaminoethylated by the reaction with dimethylaminoethyl chloride in the presence of NaH under DMAC solution. By the combination of dimethylaminoethylated hydroxypropyl chitosan and Rh 6 (CO) 16 , benzaldehyde and nitrobenzene could be converted into correspondingly reductive products in high yields under the WGSR condition.