木质素碳基固体酸介孔材料制备及其催化蒎烯水合反应机理

Carbon-based solid acid would have wide application prospects for its stable framework, high density of acids site and excellent performance price ratio. In this project, carbon-based solid acids derived from lignin will be prepared via hydrogel preparation, then drying by supercritical fluid drying methods or lyophilization, incomplete carbonization and sulfonation. The carbon-based solid acids mesoporous materials with large specific surface area, adjustable pore structure, high density of sulfonic acid groups and adjustable amphipathic surface will be obtained by using suitable cross-linking agent and optimization of every preparation procedure. The carbon-based solid acids were used as catalysts in hydration of pinene to systhesize terpilenol and camphol. The effects of the specific surface area, texture of pore, density of acid sites, amphipathy on surface and morphology about the catalysts on catalytic performance will be discussed via optimization of hydration condition and study of thermodynamics and reaction dynamics. The machanism of pinene hydration using the carbon-based solid acids as catalysts will be explored in order to provide the basic data and theoretical guide to the preparation and application of carbon-based solid acids derived from lignin which were cheap and environment-friendly catalysts for pinene hydration. This application is aim at the preparation of carbon-based solid acids mesporous materials derived from lignin and their use as catalysts in pinene hydration. It is significantly important to find a pathway for high value-added utilization of lignin from pulping, explore a green chemistry technology for pinene hydration to substitute classical technology in which sufuric acid was used as a catalyst, protect the environment and promote economic and social development in Guangxi.

碳基固体酸因其稳定的骨架结构、高密度的酸活性中心和优良的性价比，具有广阔的开发应用前景。本项目拟采用溶胶-凝胶法制备木质素水凝胶，通过超临界干燥或真空冷冻干燥得到木质素干凝胶，再经过不完全碳化和磺化得到木质素碳基固体酸介孔材料。通过选择适当的交联剂，并调控制备各步条件，可得到比表面积大、孔结构可控、磺酸基密度高、表面两亲性质可调的木质素碳基固体酸介孔材料，并用于催化蒎烯水合合成松油醇和龙脑。通过对水合反应条件的优化及对反应热力学、动力学研究，探索木质素碳基固体酸的比表面积、孔结构、酸密度、表面两亲性质和形貌等因素对蒎烯水合反应催化性能的影响，揭示该催化反应机理，为性价比高、环境友好木质素碳基固体酸介孔材料的制备和应用提供基础数据和理论依据。本申请对于解决造纸废液中木质素的资源化利用，探索松油醇、龙脑绿色化学合成工艺，保护环境，促进广西经济和社会发展具有重要意义。

随着全球环境问题的日益突出，环境友好的绿色化工工艺越来越受到人们推崇和重视。采用固体酸替代液体酸应用于各种酸催化领域，是减轻设备腐蚀、降低能源消耗、简化生产过程、实现绿色化工生产和减少环境污染的重要途径之一。本项目以木质素为主要原料，通过化学法活化、磺化，或者通过合成木质素干凝胶（或气凝胶）、炭化和磺化的方法，制备得到了比表面积较大、孔结构可调、磺酸密度较高并伴有丰富酸性含氧基团、表面两亲性质优异，并具有多层级孔隙结构的木质素碳基固体酸。其中以氢氧化钾活化木质素、浓硫酸磺化制备的碳基固体酸的比表面积达到400.6m2/g、磺酸值为0.92mmol/g、总酸值达到4.34mmol/g、水接触角为43.4º，具有大孔、中孔和微孔的多层级孔隙结构。该催化剂不仅能为蒎烯水合反应提供充足的反应活性中心和反应场所，而且能为反应物料传输提供良好的传质通道，并可有效提高了目标产物的选择性和收率。该催化剂表面对α-蒎烯和水均有良好的亲和力，具有良好的水合反应催化性能，α-蒎烯的转化率达到97.8%，α-松油醇的选择性为53.4%，α-松油醇的产率达到52.2%，明显优于在同样条件下的硫酸和强酸型阳离子交换树脂。.项目采用了Boehm滴定、BET法、SEM、XRD、FTIR、XPS、GC、GC-MS、拉曼光谱、元素分析、接触角等多种测试手段和方法，对碳基固体酸及其中间产物、蒎烯水合反应及其催化剂的性能评价进行了较系统的测定和表征，优化了碳基固体酸的制备、水合催化反应的工艺条件，探讨了催化剂的比表面积、孔隙结构、表面酸性官能基团、表面两亲性等结构与水合催化性能之间的构效关系，研究了催化反应化学热力学，初步揭示木质素碳基固体酸介孔材料催化蒎烯水合反应机理，为环境友好、性价比高的木质素碳基固体酸催化剂的制备和应用提供了基础数据和理论依据。.本项目获得的重要数据和成果，对于解决造纸废液中木质素的高值化资源化利用，探索以环境友好的固体酸代替液体酸应用于化工生产，探索绿色、清洁、环境化工生产技术，促进经济、社会和环境协调发展具有重要意义。