Preparation of lactic acid from glucose in ionic liquid solvent system

A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the catalytic performance of the solid bases was evaluated. Both the reaction temperature and time can affect the yield of lactic acid. A high yield (97%) of lactic acid was achieved under the optimal reaction condition. The 1H NMR spectra and HPLC-MS were used to identify the formation of the lact...     

微晶纤维素在SnOx/γ-Al_2O_3催化剂上的催化醇解反应研究

以γ-Al2O3为载体,采用浸渍沉淀法,制备了不同SnOx负载量的SnOx/γ-Al2O3催化剂,采用X射线光电子能谱法(XPS)和吡啶吸附红外(Py-IR)光谱法对催化剂活性中心和表面酸性进行了表征,考察了不同载体和SnOx不同负载量的SnOx/γ-Al2O3催化剂对微晶纤维素催化醇解活性和产物分布的影响规律。结果表明,催化剂活性及产物分布与催化剂的表面酸性及SnOx负载量有关,载体表面较强的B酸中心有利于促进微晶纤维素催化醇解生成乙酰丙酸甲酯,而中等强度L酸中心有利于生成乳酸甲酯。以SnOx/γ-Al2O3为催化剂时,催化剂活性和乳酸甲酯生成量随SnOx负载量增加而增加,当Sn的负载量为6.75wt%时,在240℃反应10 h,微晶纤维素的转化率达82%,乳酸甲酯的收率达到28.1%。     

在离子液体中锡催化多糖分解合成乳酸

淀粉和纤维素能够被四氯化锡催化转化为乳酸甲酯和乳酸,使用离子液体是实现多糖转化的关键。在实验中考察了催化剂、离子液体、反应时间和反应温度对于总乳酸收率的影响。实验结果显示,在1,3-二甲基咪唑硫酸甲酯盐中的淀粉在140℃条件下反应2 h可获得54%总乳酸收率,纤维素的收率为15.1%。果糖在同样的反应条件下收率为95%,葡萄糖为64%,这意味着反应机理可能为纤维素和淀粉首先降解为葡萄糖,然后异构为果糖,最终果糖分解为乳酸。