Solid acid catalyzed aldol dimerization of levulinic acid for the preparation of C10 renewable fuel and chemical feedstocks
Solid acid catalyzed aldol dimerization of levulinic acid for the preparation of C10 renewable fuel and chemical feedstocks
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DOI：
10.1016/j.catcom.2019.02.022
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发表时间：
2019-05-05
影响因子：
3.7
通讯作者：
Margetic, Davor
中科院分区：
文献类型：
--
作者：
Amarasekara, Ananda S.;Wiredu, Bernard;Margetic, Davor
研究了在110-130 ℃的纯条件下，使用一系列固体酸催化剂：Amberlyst-15、SiO2-SO 3 H、Dowex 50 WX 8、Carbon-SO 3 H、TiO 2-SO 3 H、Al 2 O3-SO 3 H、H3 PW 12 O 40和Nb 2 O 5中心点H2O，酸催化乙酰丙酸缩合反应。主要的二聚产物被鉴定为四氢-2-甲基-5，γ-二氧代-2-呋喃戊酸。此外，通过光谱和计算方法鉴定了4个次要产物为3-（2-甲基-5-氧代-四氢呋喃-2-基）-4-氧代戊酸和3-乙酰基-2-甲基-四氢-5-氧代-2-呋喃丙酸的非对映体对。提出了一种机制来解释五种二聚产物的形成，其中主要产物是通过C5烯醇形式的乙酰丙酸的羟醛缩合形成的，四种次要产物是由C3烯醇形式的乙酰丙酸的羟醛缩合产生的。以SiO_2-SO_3H为固体酸催化剂，剩余物料为未反应的乙酰丙酸，总收率最高，为56%。SiO_2-SO_3H催化剂可重复使用4次，催化活性有所损失。
The acid catalyzed condensation of levulinic acid was studied using a series of solid acid catalysts: Amberlyst-15, SiO2-SO3H, Dowex50WX8, Carbon-SO3H, TiO2-SO3H, Al2O3-SO3H, H3PW12O40, and Nb2O5 center dot H2O under neat conditions at 110-130 degrees C. The major dimerization product was identified as tetrahydro-2-methy1-5,gamma-dioxo-2-furanpentanoic acid. In addition, four minor products were identified as diastereomeric pairs of 3-(2-methy1-5oxo-tetrahydrofuran-2-yl)-4-oxopentanoic acid and 3-acetyl-2-methyl-tetrahydro-5-oxo-2-furanpropanoic acid by spectroscopic and computational methods. A mechanism is proposed to explain the formation of five dimerization products where the major product is formed via the aldol condensation of C5 enol form of levulinic acid and four minor products are arising from the aldol condensations C3 enol form of levulinic acid. The highest total yield 56% was obtained with the use SiO2-SO3H as the solid acid catalyst and the reminder of the mass balance was unreacted levulinic acid. The SiO2-SO3H catalyst could be recycled four times with some loss in catalytic activity.