生物炭基固体酸的制备及其对合成2-叔丁基对苯二酚的催化性能

以黑液固形物和松木粉为原料,经炭化、磺化制备得到黑液固形物磺化固体酸(BLSBC)和松木粉磺化固体酸(WMBC),采用扫描电镜(SEM)、热重分析(TG)、红外光谱(FT-IR)及元素分析对2种生物质炭基固体酸进行表征,并将BLSBC和WMBC催化对苯二酚(HQ)烷基化合成2-叔丁基对苯二酚(2-TBHQ),考察了原料种类和炭化温度对生物基固体酸催化性能的影响。研究结果表明:生物炭固体酸催化剂200℃以内的热稳定性良好,功能基团—SO_3H被成功接枝;催化剂C元素含量的增加及H~+交换容量的降低则归结于温度的影响,同温度条件下WMBC的H~+交换容量高于BLSBC。HQ转化率随着催化剂的H~+交换容量的降低而不断降低,而2-TBHQ选择性则取决于H~+交换容量与羟基含量的协同效应;与商业催化剂Amberlyst-15树脂、732树脂相比,450℃制备得到的WMBC(WMBC-450)表现出更高的催化活性,2-TBHQ有最高的选择性(83.8%)和产率(57.6%)。

Preparation of Sulfonated Biochar Catalysts and Their Application in 2-TBHQ Synthesis

Black liquor solid ( BLS) and wood meal ( WM) were selected as raw materials. The black liquor solid base catalysts (BLSBC) and wood meal base catalysts (WMBC) were prepared by carbonization and sulfonation. The biomass carbon based solid acids were characterized by SEM,TG,FT-IR and elemental analysis. Then these two kinds of the catalysts were applied to synthesize 2-TBHQ. The results showed that the sulfonated biochar catalysts have good thermal stability below 200 ℃, and successfully grafted with functional group—SO3 H. The increase of carbon content and the decrease exchange capacity of H+ were mainly due to the influence of the temperature,and the exchange capacity of H+ in wood meal solid acid catalyst was higher than black liquor solid acid catalyst under the same temperature. Conversion of hydroquinone decreased as the exchange capacity of H+decrease,and the selectively of 2-TBHQ was correlated well with the synergetic effect of exchange capacity of H+ and content of hydroxyl groups. WMBC-450 exhibited better catalytic selection than commercial solid acid catalysts ( amberlyst-15 and 732 ion exchange resin),and the highest selection and yield of 2-TBHQ were 83. 8 % and 57. 6 %,respectively.