In conclusion, the succinoylation of various lignins in
aqueous alkaline solution was simple, eective, seemingly
inexpensive, and environmental friendly, although the
degree of substitution was low. The isolation of succi-
nylated lignin preparations was collectively easy by one-
step precipitation, in which noticeable amounts of the
product (8.6±9.8% of the initial parent lignins) could
not be recovered due to the soluble in an aqueous solu-
tion of pH 3. An increase in molar ratio of succinic
anhydride/C9 unit of lignin from 0.5/1 to 1.5/1 led to
growth of the succinylated lignin from 94.7% to 108.6%.
Similar increasing trend was also observed during the
extension of reaction time from 1 to 4 h. The thermal
stability of the product was increased by chemical suc-
cinoylation.