基于结构修饰的木质素解聚制备高收率单酚类化合物及其机理研究

Lignin is the only renewable biomass resource containing aromatic structures available on earth. It is of very importance to depolymerize lignin into phenolics with small molecular weight for both high efficient utilization of the renewable biomass and substitution of the fossil resources and energy. The key to achieve this goal is how to facilitate the clevage of linking bond among stuctural subunits and prevent recondensation of the depolymerized products. Based on density functional theory, this proposal starts from structral modifications followed by hydrogenolysis to producce monophenols by using dimeric, trimeric and tetrameric model compounds togather with lignin. The structural modification includes the methoxylation and formation of 1,3-dioxane structure of Cα-alcoholic hydroxyl group, the methoxylation of active C3 and C5 site in the benzene ring by chemical or enzymatic reaction. The effect of structral modification of functional groups the facilitate the clevage of linking bond among stuctural subunits and prevent recondensation of the depolymerized products will be explored conbining with DFT calculation. The key intrinsic key controlling factors and mechanism will be revealed and regulated by comparing the contents and their distribution of depolymierized products to realize the possible pathway of the structral modification. This research will provide theoretical basis and realizable routes for high efficient depolymerization of lignin and high-yield production of phenolics, and hence break through the bottleneck of biomass for the high efficient utilization of lignocellulose, and promote the sustainable development of society.

木质素是自然界中唯一含苯环结构的可再生资源，利用木质素制备高收率单酚类化合物对于可再生资源的高效利用及化石资源和能源的替代具有重要意义。实现该目标的关键是如何促进结构单元联接键的断裂和防止解聚产物的重聚。项目以木质素模型化合物结合木质素为研究对象，从密度泛函理论出发，分别对Cα醇羟基进行甲氧基化、1,3-二氧六环化；苯环结构活性C3、C5位的甲氧基化或酶解等结构修饰后进行氢解，结合密度泛函理论计算，探索木质素的结构修饰对于促进β-O-4芳醚键断裂以及解聚产物阻聚的影响规律。通过对比模型物和木质素的解聚产物分布和含量，揭示木质素解聚获得高收率单酚类化合物的关键内在控制因素和机理，获得可行的结构修饰途径，实现木质素解聚产物的调控，为木质素的高效解聚和获得高收率的单酚类化合物提供理论基础和可实现的途径，突破生物质高效利用的瓶颈，进而全组分高效利用木质纤维素生物质资源，促进社会可持续发展。

围绕项目的总体目标和思路，按照课题的任务，围绕木质素结构特性，从密度泛函理论出发，分别对Cα醇羟基进行甲氧基化、苯环结构活性C3、C5位的卤代-甲氧基化以及酶解等结构修饰，然后进行氢解，结合密度泛函理论计算，探索木质素模型化合物及其真实木质素的结构修饰对于木质素解聚过程中β-O-4芳醚键断裂的促进作用以及解聚产物重新聚合的防止的影响规律的基础上，揭示木质素解聚获得高收率单酚类化合物的关键控制因素和机理。最后，在木质素结构修饰的基础上，研究了多级孔掺氮炭载体负载钌基催化剂高效解聚木质素，实现木质素解聚产物的调控，为真实木质素的高效解聚和获得高收率的单酚类化合物提供理论基础、指导和可实现的途径。促进木质素高效资源化利用，突破生物质高效利用的瓶颈，进而全组分高效利用木质纤维素生物质资源，促进社会可持续发展。