Toward Functional Polyester Building Blocks from Renewable Glycolaldehyde with Sn Cascade Catalysis
作者:Michiel Dusselier、Pieter Van Wouwe、Sanne De Smet、Rik De Clercq、Leander Verbelen、Peter Van Puyvelde、Filip E. Du Prez、Bert F. Sels
DOI:10.1021/cs400298n
日期:2013.8.2
corresponding vinyl glycolate esters arose as the main product. Vinyl glycolic acid, 2,4-dihydroxybutanoic acid, and its lactone were formed significantly in nonprotic solvent. The corresponding AHAs have serious potential as building blocks in novel biobased polymers with tunable functionality. The incorporation of vinyl glycolic acid in polylactic acid-based polyesters is illustrated, and postmodification
受围绕生命起源的基于formose的假设的启发,我们报告了一条新颖的催化路线,该路线通往一系列新发现的四碳α-羟基酸(AHA)及其来自各种可及的可再生乙醇醛(GA)的酯溶剂。合成路线遵循级联反应网络,并通过原位13 C NMR研究了其确定速率决定步骤的机理。机理上的理解通过平衡布朗斯台德酸和路易斯酸活性(两者均源自卤化锡催化剂),从而优化了反应条件,提高了AHA的总体形成速率。最佳H +/ Sn比为3,并且这个数字令人惊讶地与Sn的氧化态无关。通过向反应混合物中添加少量水,进一步提高速率,与纯甲醇溶剂相比,将速率提高4.5倍。级联反应选择性地产生接近60%的4-甲氧基-2-羟基丁酸甲酯(MMHB)。在甲醇的优化速率方案中,初始TOF为7.4 mol GA mol Sn –1 h –1被找到。在位阻醇(异丙醇)中,AHA的形成率甚至更高,并且相应的乙醇酸乙烯酯是主要产物。乙烯基乙醇酸,2