共反应剂法均相合成长链脂肪酸纤维素酯

Homogeneous Synthesis of Long-Chain Fatty Acid Cellulose Esters with p-Toluenesulfonyl Chlorid as Coreactant

在纤维素(棉浆粕)的LiCl/N,N-二甲基乙酰胺均相溶液中,以对甲苯磺酰氯(TosCl)为共反应剂,原位活化长链脂肪酸,合成了长链脂肪酸纤维素酯;采用FTIR、1H NMR、XRD和热重分析等手段对产物进行了表征;考察了长链脂肪酸中的碳原子数、反应物配比、反应温度、反应时间等因素对产物取代度的影响。实验结果表明,当n(反应物纤维素葡萄糖苷)∶n(长链脂肪酸)∶n(TosCl)=1∶3∶3、反应温度85℃、反应时间24h时,产物取代度较高;且随长链脂肪酸碳原子数目的增加,产物取代度下降。表征结果表明,与纤维素相比,长链脂肪酸纤维素酯的结晶度下降,使其在有机溶剂中的溶解性增强;酯化反应削弱了纤维素分子间及分子内的作用力,赋予了长链脂肪酸纤维素酯较低的热加工温度。

Long-chain fatty acid cellulose esters were synthesized through in-situ activation of long-chain fatty acids with p-toluenesulfonyl chloride as coreactant in cellulose（cotton pulp）-LiCl/N,N-dimethylacetamide homogenous solution.The long-chain fatty acid cellulose esters were characterized by means of FTIR,～（1）H NMR,XRD and TG.Effects of the esterification reaction conditions on degree of substitution（DS）of the product were investigated.The results showed that the long-chain fatty acid cellulose ester with the highest DS could be synthesized under the conditions of 85 ℃,mole ratio of repeated glucoside units in the cellulose molecular chain,long-chain fatty acid and p-toluenesulfonyl chloride 1∶3∶3,and 24 h.And the degree of esterification decreased with increase of carbon atom number of the long-chain fatty acids.XRD analysis showed that crystallinities of the long-chain fatty acid cellulose esters were lower than that of cellulose,which could heighten their dissolubilities in organic solvents.TG analysis revealed that the esterification could weaken the action both between and within the cellulose molecules,which could lower heat processing temperatures of the long-chain fatty acid cellulose esters.