Catalytic dehydration of lactic acid and its esters is a promising approach to renewably produce acrylic acid and its esters. Molecular level understanding of the dehydration reaction mechanism on NaY has been achieved via a combination of reactivity and in-situ transmission Fourier transform infrared (FTIR) spectroscopic investigations. Brønsted acid sites generated in-situ with the assistance of water have been identified as the primary active sites for the dehydration pathway. The key branching point between the desired dehydration and undesired decarbonylation pathways is the dissociation of methyl lactate on NaY to form adsorbed sodium lactate and methyl groups. Brønsted and Lewis acid sites mainly catalyze the dehydration of adsorbed sodium lactate, whereas the decarbonylation pathway to acetaldehyde dominates when methyl lactate is not dissociated. Similar mechanistic steps are likely followed in the catalytic dehydration of lactic acid to acrylic acid. The mechanistic understanding gained will enable rational design of catalysts for selective dehydration of methyl lactate.

乳酸及其酯的催化脱水是可再生地生产丙烯酸及其酯的有前途的方法。通过反应性和原位透射傅立叶变换红外（FTIR）光谱学研究相结合，已实现了对NaY脱水反应机理的分子水平的了解。在水的帮助下原位产生的布朗斯台德酸位点已被确定为脱水途径的主要活性位点。所需的脱水和不希望的脱羰途径之间的关键分支点是乳酸甲酯在NaY上的离解，从而形成吸附的乳酸钠和甲基。布朗斯台德和路易斯酸位点主要催化吸附的乳酸钠的脱水，而当乳酸甲酯未解离时，通往乙醛的脱羰途径占主导。在乳酸催化脱水成丙烯酸中可能遵循类似的机械步骤。所获得的机理理解将使合理设计乳酸甲酯选择性脱水的催化剂成为可能。