Synthesis and Structural Analysis of Sulfated Carboxymethyl Chitin

Abstract

Sulfation of carboxymethyl-chitin (CM-chitin) was investigated. CM-chitin was converted to tri-n-butylammonium salt, in order to increase its solubility in DMF, then sulfated using sulfur trioxide-pyridine complex. The degree of sulfation of the sulfated carboxymethyl-chitin (SCM-chitin) obtained from CM-chitin with DS 0.50 and 0.80 (CM50, CM80) was in the range of 0.19 to 1.20. From the ¹³C-NMR analysis, degree of N-deacetylation of CM80 was 0.30 and the reactivity of hydroxyl and amino groups against SO₃-pyridine is in the order of C6-OH>C2-NH₂>>C3-OH. On the other hand, degree of deacetylation of CM50 was 0.20 and sulfation occurred at C6-OH and C2-NH₂. The X-ray diffraction diagrams showed that crystallinity of CM80 was lower than CM50.