玉米芯碳基固体酸含盐氛围水热法制备

以富碳农业废弃物——玉米芯为原料,通过含盐氛围水热法制备了玉米芯碳基固体酸。考察了制备条件对碳基固体酸催化活性的影响,通过表征分析,对含盐氛围水热法的制备机理及固体酸的构-效关系进行了探讨,研究了该固体酸催化高酸值餐饮废油酯化降酸的条件和效果。结果表明:Zn Cl2能够有效促进玉米芯的水热碳化,将碳化速率提高一倍,为后继磺化提供理想的载体;含盐氛围水热法制备的碳基固体酸,磺酸基团密度大,油酸酯化率是同等条件下传统水热法的4.5倍。在最佳的酯化条件下反应4 h,玉米芯碳基固体酸催化餐饮废油中游离脂肪酸的酯化率可达90.23%。

Hydrothermal Preparation of Corncob-derived Solid Acid Catalysts under Saline Condition

Novel corncob-derived solid acid catalysts, which used corncob as a precursor, were successfully synthesized for the first time by hydrothermal method under saline condition. The effects of different preparation parameters on the catalytic activity of the corncob-derived solid acid were investigated by using the esterification reaction of oleic acid with methanol. The structure-function relationships of the resulting catalysts were also discussed in detail on the basis of the analysis of structure and composition. Then, the catalytic activity of the resulting solid acid was investigated by using the esterification reaction of waste cooking oil with high acid value. The results indicated that the presence of ZnCl2 yielded a preferable carbonaceous structure composed of polycyclic aromatic carbon sheets in short carbonization time. Compared with the conventional method, the carbonized rate of corncob under saline conditions was increased by 1 time, which also produced a suitable structure for sulfonation process. The resulting solid acid possessed high SO3H density, which caused 4.5 times higher esterification yield of methyl oleate than the solid acid prepared by conventional hydrothermal method. Moreover, the corncob-derived catalyst synthesized under optimized saline conditions exhibited higher catalytic activity in esterification reactions of waste cooking oil, yielding 90.23% fatty acid methyl ester in only 4h.