Synthesis of Carboxymethyl Polysaccharide from Arenga Pinnata Polysaccharide and Monochloroasetic

Abstract

Synthesis of carboxymethyl polysaccharide Arenga pinnata has been prepared through etherification of Arenga pinnata polysaccharide and monochloroacetate (MCA). Firstly the polysaccharide was extracted from Arenga pinnata endosperm with different toughness (soft and hard) followed by etherification with monochloroacetate using sodium hydroxide as a catalyst with variation of molar ratio MCA : NaOH of 0.50; 0.55; and 0.60 and ethanol 96% as solvent at temperature of 60 C for 10 hours in oven. The substitution degree was determined using titration method in which the Na-carboxymethyl was hydrolysis with HCl 2M in methanol 70% to form carboxymethyl polysaccharide. The yields of carboxymethyl polysaccharide were 90% and 83% for hard and soft, respectively. The substitution degree of carboxymethyl polysaccharide from soft Arenga pinnata endosperm was 1.600; 1.068 and 0.403 and from hard endosperm was 0.688; 0.467 and 0.202. The substitution degree of carboxymethyl polysaccharide was increased in the increasing of NaOH used which polysaccharide from Arenga pinnata endosperm soft has higher substitution degree than from the hard. The appearance stretching vibration of the carbonyl group (C=O) at a wavelength of 1730 cm-1 confirmed the formation of carboxymethyl polysaccharide. The morphology surface of carboxymethyl polysaccharide showed rough surface than Arenga pinnata polysaccharide revealed that the granule of polysaccharide have been changed.