## 1 Introduction  
With the growing perception for the need for sustainability at global scale, alternative fuels and fuel additives for transport has gained more attention. The intensive consumption of fossil fuels, the depletion of natural resources and the concomitant environmental concerns drive a progressive change to green processes [1]. This fact is also reflected in the gradual increase in the share of energy use based on renewable sources that has been encouraged throughout the world in the early years of the present century, in particular in the European Union [2]. As a consequence, a fast growth in the biodiesel industry has taken place in the last decades, as it has received worldwide attention as a medium-term alternative to diesel fuel obtained from petroleum. Biodiesel mixtures are chemically simple: they are in essence fatty acid methyl or ethyl esters. They have the texture of a yellow liquid and are immiscible in water, have a high boiling point and a low vapor pressure, and are not very flammable (370 to 440 K), while their densities are lower than that of water (\(-0.86\) g\(\cdot\)cm\({}^{-3}\)). Usually, biodiesel is obtained by transesterification of vegetable oils and/or animal fats, with the concomitant production of glycerol, a by-product whose production increase is calling for novel processes and products based on this platform chemical. A derivative of glycerol, glycerol carbonate (GC) is a chemical of high interest due to its many applications as a polyvalent green solvent [3] or as a reagent to treat biomass through acid pretreatments, e.g., sugarcane bagasse [4] and rice husk [5]. Thanks to its non-toxic properties, this carbonate has been applied in cosmetic products, for example as a component in nail polish remover gel, emulsifier, as plasticizer, and as humectant. Over the past two years, there has been an increase in the number of patents filed where GC was used in hair (shaping, dyeing) or skin (lightening, bleaching) applications [6]. There are several methods and approaches to synthesize GC from glycerol, which will react with different sources of carbonate, such as CO/O\({}_{2}\), CO\({}_{2}\), organic carbonate, urea, or phosgene [7]. Glycerol carbonylation with phosgene or CO is a synthetic route which has been used for several years for the production of GC, but due to the high toxicity and the caustic aspect of the reagents, this method of synthesis has been abandoned over time [8; 9]. Recently, studies have clearly mentioned that the use of CO\({}_{2}\) as a source of carbonate for the synthesis of GC is an ideal approach. However, this method suffers from a very limited overall activity due to the difficulty in activating the CO\({}_{2}\). Likewise, when using urea as a reagent, the by-product NH\({}_{3}\) needs to be removed continuously during the reaction. Lately, various non-toxic, safer, and environmentally friendly synthetic routes have been developed for the production of GC based on organic carbonates. One route of this kind is the transcarbonation of glycerol with dimethyl carbonate (DMC) [10], which acts as an excellent solvent [11]. Another targeted method for the production of glycerol carbonates described in the literature is the glycerol transcarbonation with cyclic carbonates: ethylene carbonate (EC) or propylene carbonate (PC) [12]. This reaction requires a basic catalyst identical or similar to those employed in the biodiesel process, working at very mild temperatures and atmospheric pressure. Sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate K\({}_{2}\)CO\({}_{3}\), and triethylamine are conventional catalysts used to produce biodiesel [13]. Although these homogeneous catalysts can produce high GC yield, they require a notable processing effort to purify the carbonate [14]. In addition, their presence can affect the purity of the fuel and cause environmental impacts. Heterogeneous catalysts are designed to overcome the disadvantages of using a homogeneous one.