Recent Development of Heterogeneous Catalysis in the Transesterification of Glycerol to Glycerol Carbonate

Abstract

Glycerol is one of the most crucial by-products in the production of biodiesel, and owing to its oversaturation in the market, several synthetic strategies have been developed to transform it into other higher value-added products such as glycerol carbonate, epichlorohydrin, 1,3-propanediol, etc. Amongst them, glycerol carbonate is considered to be the most valuable product. Considering the facile separation and reusability of catalyst, heterogeneous base catalysts have attracted considerable attention due to the obvious advantages over Brϕnsted acid and homogeneous base catalysts in the transesterification of glycerol. Herein, we will give a short overview on the recent development of the heterogeneous catalysis in the transesterification of glycerol with dialkyl carbonate. Focus will be concentrated on the heterogeneous base catalysts including alkaline-earth metal oxides (MgO, CaO, and mixed oxides), hydrotalcites, zeolites, clinoptilolites, organic bases, etc. Their catalytic mechanisms during the heterogeneous process will be elucidated in detail.

Recent Advances in Glycerol Catalytic Valorization: A Review

“…Glycerol carbonate is a high value-added product with a high market price, which can be used in the synthesis of biopolymers, methylating agents, and methoxycarbonylating agents [24,207]. The production of glycerol carbonate from glycerol can be catalyzed by inorganic (commonly alkaline earth metal oxides and hydrotalcites) or organic (biocatalyst) compounds, for instance, Candida antarctica lipase B supported on Accurel MP1000 (CalBAcc) [208].…”

“…Indirect routes normally lead to a higher yield of glycerol carbonate, where the catalysts play a key role. Starting with glycerol transesterification, some reviews have summarized the types of catalysts [207,211], which are very similar to other transesterification processes, including K 2 CO 3 , CaO, MgO [213], ZnO, and H 2 SO 4 . Several types of hydrotalcite have been tested, such as Al/Mg, Al/Li, Al/Ca, Mg/Al, etc.…”

Nanoarcillas sintéticas para ser empleadas en la valorización de glicerol a carbonato de glicerilo

“…4), lo que corresponde a un aumento en la fuerza del sitio ácido y también se observa un incremento en el número de dichos sitios. Coincidiendo con lo planteado por Ji y col. es factible que la actividad catalítica de los óxidos mixtos pueda atribuirse a una combinación de sitios básicos y ácidos superficiales (Ji, 2019).…”

“…Los resultados actuales apuntan a que los sitios básicos fuertes de los OMM de Cu juegan un papel importante en la adquisición de un alto rendimiento de CG. No obstante, un mecanismo de reacción hipotético para la transesterificación de glicerol con EC podría ser promovido mediante dos modos de activación, que involucran sitios básicos y ácidos (Ji, 2019).…”

Biodiesel at the Crossroads: A Critical Review

“…Consequently, its utilization as a reaction medium as well as a phosgene substitute has currently been attracting much interest because of DMCs ability to act on a wide variety of reactions such as polycarbonate synthesis, polyurethane synthesis, carboxylation reagents, alkylating reagents, and polar solvents, not to mention its application as a fuel additive. In fact, DMC is also employed to obtain glycerol carbonate, considered an added-value product to revalorize the glycerol [179][180][181][182][183][184][185][186][187][188][189][190][191].…”