Controllable functionalization of targeted oxygen-containing species of biomass feedstocks is one of the prevalent approaches to biofuels and important chemicals, and well-designed functional catalytic materials are typically required to promote the smooth proceeding of the desired conversion processes. In this work, HCOONH₄ was demonstrated to be capable of acting as both hydrogen and nitrogen source in the absence of any catalyst and additive for the reductive cycloamination of bio-based levulinic acid (LA) to 5-methyl-2-pyrrolidone (MPL) with more than 90 % in just 60 min at 180 °C. Pressurized hot water remarkably enabled the reaction efficiency and rate by promoting the hydrolysis of HCOONH₄ to liberate ammonia and formic acid for the cascade reactions, and this catalyst-free protocol is also applicable to the efficient synthesis of various cyclic amides from relevant keto acids. Moreover, the reaction pathways were investigated by conducting deuterium-labeling experiments and kinetic studies of selected reactions.

生物质原料的目标含氧物种的可控功能化是生物燃料和重要化学品的普遍方法之一，通常需要精心设计的功能性催化材料以促进所需转化过程的顺利进行。在这项工作中，HCOONH ₄被证明能够在没有任何催化剂和添加剂的情况下充当氢和氮源，用于将生物基乙酰丙酸（LA）还原环胺化为5-甲基-2-吡咯烷酮（MPL） ）在180°C下仅需60分钟即可获得超过90％的流量。加压热水通过促进HCOONH ₄的水解显着提高了反应效率和速率从而释放出氨和甲酸以进行级联反应，该无催化剂方案也适用于由相关的酮酸有效合成各种环酰胺的情况。此外，通过进行氘标记实验和选定反应的动力学研究，研究了反应途径。