Synthesis of completely biobased lignin-formaldehyde resins with catalytically activated lignin products

拟议中的项目旨在开发一种化学过程，将植物中发现的一种名为木质素的材料转化为一种更有价值的材料，名为木质素甲醛(LF)树脂。完全生物基的LF树脂可以取代苯酚-甲醛树脂，苯酚-甲醛树脂是一种常见的材料，用于各种工业产品，如台面、涂料、胶粘剂、台球等。木质素含有酚类单元，使其在树脂合成中成为苯酚的潜在可再生替代品。然而，木质素本身对甲醛的反应能力有限。为了克服这一问题，提出了一种新的催化工艺来提高木质素产品的反应活性。拟议的研究可能导致开发增加生物质废物木质素价值的技术，并可对环境和农村经济产生积极影响。木质素催化解聚和去甲氧基化成小碎片可以产生自由酚羟基和自由邻位甲醛加成和交联。该途径可以克服木质素对甲醛反应的局限性。初步结果表明，廉价的催化剂，如金属硫化物，可以催化木质素的解聚和脱甲氧基。LF树脂随后可以由具有两个邻位的酚类化合物合成，并通过添加多个邻位化合物来固化。将通过对具有各种单元间连接的二聚体的模型化合物研究来筛选催化剂。通过用模型化合物合成LF树脂，研究了合成LF树脂的最佳单体/二聚体(和/或低聚物)配比。研究成果将被纳入弗吉尼亚理工学院和州立大学的课程，旨在教育学生有关生物质衍生燃料和增值产品的知识。计划开展面向高中生的外展活动，重点是吸引代表不足的群体成员投身科学和工程领域的职业生涯。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The proposed project aims to develop a chemical process to convert a material found in plants called lignin to a more valuable material called lignin-formaldehyde (LF) resin. Completely bio-based LF resins can replace of phenol-formaldehyde resins, which a common material used in myriad of industrial products, such as countertops, coatings, adhesives, billiard balls, etc. Lignin contains phenolic units that make it a potential renewable substitute for phenol in the synthesis of the resin. However, lignin itself has limited reactivity towards formaldehyde. To overcome this problem, a new catalytic process is proposed to enhance the reactivity of lignin products. The proposed research may lead to the development of technologies that add value to lignin from biomass waste streams and can have positive impact on the environment and on rural economies. Catalytic depolymerization and demethoxylation of lignin into small fragments can generate free phenolic hydroxyls and free ortho positions for formaldehyde addition and crosslinking. This pathway can overcome the limited reactivity of lignin towards formaldehyde. Preliminary results have shown that inexpensive catalysts, such as metal sulfides, could catalyze depolymerization and demethoxylation of lignin. LF resins can be subsequently synthesized from phenolic compounds with two ortho positions and be cured with the addition of multiple-ortho-position compounds. Catalysts will be screened through model compound studies on dimers featuring various kinds of interunit linkages. The optimal ratios of monomer/dimers (and/or oligomers) for LF resin synthesis will by studied by synthesizing LF resins from model compounds. The research results will be incorporated in courses at Virginia Polytechnic Institute and State University aimed at educating students about biomass-derived fuels and value-added products. Outreach activities to high school students are planned with emphasis on attracting members of underrepresented groups into pursuing careers in science and engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.