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以微晶纤维素为原料,浓硫酸为催化剂,制备了一系列不同取代度的纤维素醋酸酯。研究了反应时间、温度、原料配比、催化剂用量对取代度和产率的影响,并通过红外图谱进行了表征。结果表明:随着反应时间、反应温度、原料配比和催化剂用量的增加,产物取代度增大,但产率降低。在温度为85℃,时间为10min,浓硫酸用量为1mL,醋酸酐与微晶纤维素的用量比为25∶1的最佳合成条件下取代度接近3,与理论值相符合。
Microcrystalline cellulose as raw material, concentrated sulfuric acid as a catalyst, prepared a series of different degrees of substitution of cellulose acetate. The effects of reaction time, temperature, ratio of raw materials and amount of catalyst on the degree of substitution and yield were investigated and characterized by IR. The results showed that with the increase of reaction time, reaction temperature, the ratio of raw materials and the amount of catalyst, the product substitution degree increased, but the yield decreased. Under the optimal conditions of the temperature of 85 ℃, the time of 10min, the concentration of sulfuric acid 1mL, acetic anhydride and microcrystalline cellulose dosage ratio of 25: 1, the degree of substitution is close to 3, which is consistent with the theoretical value.