Abstract:

Lignocellulose is an abundant biomass resource in nature, in which hemicellulose and cellulose can be converted into two important platform chemicals—furfural and 5-hydroxymethylfurfural after hydrolysis and dehydration, and other platform chemicals can be acquired from them through hydrogenation or other methods. Carbon-carbon coupling of these platform chemicals can produce oxygenated compounds above C₈, and then long-chain alkanes can be obtained through hydrodeoxygenation. After subsequent treatment, they can be used as aviation kerosene, etc. Therefore, carbon-carbon coupling and hydrodeoxygenation are the keys to the conversion of holocellulose derivatives into biofuels. In this paper, heterogeneous catalysts and their catalytic mechanisms for two important carbon chain extension reactions—aldol condensation and hydroxyalkylation/alkylation are reviewed first. The catalysts mainly include alkaline catalysts, acidic catalysts and acid-base synergistic catalysts for aldol condensation reaction, and acidic catalysts for hydroxyalkylation/alkylation reaction. Then the catalysts used in the subsequent hydrodeoxygenation process are briefly introduced, and finally the development direction of catalysts in the future is prospected.

Key words: holocellulose, aldol condensation, hydroxyalkylation/alkylation, alkaline catalyst, acidic catalyst

摘要：

木质纤维素是自然界中储量丰富的生物质资源，其中的半纤维素和纤维素经水解、脱水后可得到两种重要的平台化学品——糠醛和5-羟甲基糠醛，而它们通过加氢等方法可获得其他的平台化学品。将这些平台化学品进行碳-碳偶联，能够得到C₈以上的含氧化合物，再通过加氢脱氧得到长链烷烃，经过后续处理用作航空煤油等，因此，碳-碳偶联及加氢脱氧是综纤维素衍生物转化合成燃料的关键。首先综述了用于两种重要的碳链增长反应（羟醛缩合与羟基烷基化/烷基化）的非均相催化剂及其催化机理，主要包括用于催化羟醛缩合反应的碱性催化剂、酸性催化剂和酸碱协同催化剂，以及用于催化羟基烷基化/烷基化反应的酸性催化剂，然后对后续加氢脱氧过程的催化剂进行了简要介绍，最后对未来催化剂发展方向进行了展望。

关键词: 综纤维素, 羟醛缩合, 羟基烷基化/烷基化, 碱性催化剂, 酸性催化剂