Synthesis of lauryl grafted sodium alginate and optimization of the reaction conditions.

Lauryl grafted sodium alginate (SA-C(12)) was prepared by the reaction between sodium alginate and dodecanol with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) as a coupling agent. The structure of SA-C(12) was confirmed by FT-IR, (1)H NMR, and thermoanalysis. Meantime, the degree of substitution (DS) of SA-C(12) was determined by GC. The reaction conditions were studied systematically, which included reaction time and temperature, the molar ratio of hexuronic acid in alginate to dodecanol (N(hexuronic)/N(dodecanol)) and N(hexuronic)/N(EDC), the mass of toluenesulfonic acid. By investigating the relationship between these conditions and DS, the optimal conditions with the maximum DS were obtained.