A fresh perspective on dissociation mechanism of cellulose in DMAc/LiCl system based on Li bond theory

In this case, various characterization technologies have been employed to probe dissociation mechanism of cellulose in N,N-dimethylacetamide/lithium chloride (DMAc/LiCl) system. These results indicate that coordination of DMAc ligands to the Li⁺-Cl^- ion pair results in the formation of a series of Li_x(DMAc)_yCl_z (x = 1, 2; y = 1, 2, 3, 4; z = 1, 2) complexes. Analysis of interaction between DMAc ligand and Li center indicate that Li bond plays a major role for the formation of these Li_x(DMAc)_yCl_z complexes. And the saturation and directionality of Li bond in these Li_x(DMAc)_yCl_z complexes are found to be a tetrahedral structure. The hydrogen bonds between two cellulose chains could be broken at the nonreduced end of cellulose molecule via combined effects of basicity of Cl^- ion and steric hindrance of [Li (DMAc)₄]⁺ unit. The unique feature of Li bond in Li_x(DMAc)_yCl_z complexes is a key factor in determination of the dissociation mechanism.