Ver Elst Céderic, Vroemans Robby, Bal Mathias, Sergeyev Sergey, Mensch Carl, Maes Bert U W
Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
Angew Chem Int Ed Engl. 2023 Nov 13;62(46):e202309597. doi: 10.1002/anie.202309597. Epub 2023 Aug 29.
Levulinic acid is a key biorenewable platform molecule. Its current chemical production from sugars is plagued by limited yields, char formation and difficult separations. An alternative and selective route starting from muconic acid via simple heating in water at high temperature (180 °C) has been developed. Muconic acid can be obtained from sugars or catechol fermentation. Chemical oxidation of catechol is another possibility which advantageously can also be applied on substituted catechols, hereby providing substituted muconic acids. When applying the disclosed hydrothermal protocol on these substrates hitherto unknown substituted levulinic acids were accessed. In particular, 3-propyllevulinic acid has been synthesized from 4-propylcatechol, prepared from pine wood. This propylated derivative has been used for the synthesis of a 3-propyllevulinate diester, i.e. butane-1,4-diyl bis(4-oxo-3-propylpentanoate), via esterification with 1,4-butanediol. The diester showed superior performance as plasticizer in comparison to the corresponding levulinate diester in both PVC (polyvinyl chloride) and PLA (polylactic acid). It plasticizes equally effective as the notorious commercial phthalate-based benchmark DEHP (di-2-ethylhexyl phthalate) in PVC.
乙酰丙酸是一种关键的生物可再生平台分子。目前由糖类化学合成乙酰丙酸存在产率有限、形成焦炭和分离困难等问题。已开发出一条从粘康酸出发，通过在高温（180℃）水中简单加热的替代且选择性的路线。粘康酸可从糖类或儿茶酚发酵获得。儿茶酚的化学氧化是另一种可能性，其有利之处还在于也可应用于取代儿茶酚，从而得到取代粘康酸。当将所公开的水热方法应用于这些底物时，可得到迄今未知的取代乙酰丙酸。特别地，已从松木制备的4-丙基儿茶酚合成了3-丙基乙酰丙酸。该丙基化衍生物已用于通过与1,4-丁二醇酯化合成3-丙基乙酰丙酸二酯，即丁烷-1,4-二醇双(4-氧代-3-丙基戊酸酯)。与PVC（聚氯乙烯）和PLA（聚乳酸）中的相应乙酰丙酸二酯相比，该二酯作为增塑剂表现出优异的性能。在PVC中，它作为增塑剂的效果与臭名昭著的商业邻苯二甲酸酯基基准DEHP（邻苯二甲酸二(2-乙基己基)酯）相当。
