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Advances in Simulated Moving Bed Technology
Published in Nelu Grinberg, Peter W. Carr, Advances in Chromatography Volume 57, 2020
Rui P. V. Faria, Jonathan C. Gonçalves, Alírio E. Rodrigues
Recently, new strategies have been proposed for the valorization of the waste glycerol from biodiesel plants. After its purification through the aforementioned processes, for instance, refined glycerol can be reacted to generate chemicals with high added value; however, the reactions involved in this processes typically generate a complex mixture of products and unconverted glycerol that requires further purification. In this context, Coelho et al. [132,133] proposed the implementation of an SMB process for the separation of glyceric and tartronic acids obtained through the aerobic oxidation of glycerol in aqueous media. Starting from a model mixture containing the two carboxylic acids, the authors demonstrated the feasibility of the process by performing the separation in a lab-scale unit comprising six columns packed with Dowex 50WX2 and using a solution of sulfuric acid at 4 mM as eluent. Under optimal conditions, the unit was able to achieve a productivity of 86 g of tartronic acid and 176 g of glyceric acid per liter of adsorbent per day, considering the typical commercial purity value of 97% of these species. The estimated eluent consumption was 0.30 liters per gram of products.
State-of-the-Art in Nanocatalysts for the Transformation of Glycerol into High Added Value Products
Published in Vanesa Calvino-Casilda, Antonio José López-Peinado, Rosa María Martín-Aranda, Elena Pérez-Mayoral, Nanocatalysis, 2019
Vanesa Calvino-Casilda, Eugenio Muñoz Camacho
In the case of Hong et al. (2014), they dispersed Cu2O rhombic and cubic nanocrystals onto graphene oxide supports obtaining catalysts highly active in the oxidation of glycerol into lactic acid. The original process of synthesis in aqueous media consisted of controlling the shape of the Cu2O nanocrystals, employing as template and surfactant graphene oxide. It seems that thanks to the graphene oxide, Cu2O nanocrystals are more stable and the catalytic activity enhances considerably. The hybrid system Cu2O-graphene oxide shows that the catalytic activity depends on the shape of the nanocrystals. At the same time, Mimura et al. (2014) stabilized effectively Au-Pd nanoparticles in an anion-exchange resin employing the ion-exchange method (Mimura et al. 2014). The preparation of the catalytic structure was controlled in order to obtain a very good dispersion of the nanoparticles. The bimetallic catalyst presented higher catalytic activity in the liquid phase glycerol oxidation with O2 than the monometallic ones. In addition, the bimetallic catalyst showed very good stability using a fixed bed flow reactor, achieving conversions of about 50% and a steady-state selectivity to tartronic acid (30%) and glyceric acid (60%).
Selective glycerol oxidation to glyceric acid under mild conditions using Pt/CeO2–ZrO2–Fe2O3/SBA-16 catalysts
Published in Journal of Asian Ceramic Societies, 2022
Yeon-Bin Choi, Naoyoshi Nunotani, Kunimitsu Morita, Nobuhito Imanaka
The catalytic liquid-phase oxidation of glycerol was carried out for Pt/xwt%CZFe/SBA at 30°C in an atmospheric open-air system. After 4 h of reaction, GA, GLA, dihydroxyacetone (DHA), hydroxypyruvic acid (HA), tartronic acid (TA), mesoxalic acid (MA), glycolic acid (GLOA), and oxalic acid (OA) were identified using HPLC. Figure 11 depicts the proposed reaction scheme of glycerol oxidation, which includes the obtained products, based on previous studies [2–5,36]. Figure 12 shows the glycerol conversion and product yields as a function of the CZFe loading amount. The glycerol conversion increased with increasing x up to the catalyst with x = 40, while the specific surface area decreased. This behavior indicates that the increase in OSC mainly affected the improvement of the catalytic activity. On the other hand, for x > 40, glycerol conversion decreased because the low specific surface area decreased the catalytic active sites. Therefore, the highest glycerol conversion was obtained for the x = 40 catalyst.
Recent developments and potential advancement in the kinetics of catalytic oxidation of glycerol
Published in Chemical Engineering Communications, 2020
Rozaini Abdullah, Syamima Nasrin Mohamed Saleh, Kartina Embong, Ahmad Zuhairi Abdullah
Katryniok et al. (2011) discussed in detail the most promising compounds that could be produced from glycerol oxidation including dihydroxyacetone (DHA), tartronic acid (TA), and mesoxalic acid (MA). Nevertheless, detailed understanding on glycerol oxidation, specifically into LA over heterogenous catalysts is still yet to be established. Hence, in this work, a critical review on the development of precious and nonprecious metals as heterogeneous catalysts to convert glycerol to LA is offered. Moreover, recent advancements in the reaction kinetics and deactivation mechanism of the catalysts are also offered in this review. These topics are critical to formulate efforts toward the development of deactivation-resistant catalysts to produce LA from glycerol. Hence, this review generally provides a critical discussion on future prospects for catalytic oxidation reaction of glycerol.
Nanotubes TiO2 supported Pt catalyst for selective electrocatalytic oxidation of glycerol to glyceric acid
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Guoxu Qin, Xinyun Wang, Xinjun Wan, Dong Chen, Bo Qiu
Biodiesel as well-established renewable fuels has been tremendously developed due to the growing environmental concern about the use of fossil fuels (Liu et al. 2014; Villa et al. 2015). Glycerol (GLY), which is an easily available biomass as a by-product in the production of biodiesel, has oversupplied (Kim et al. 2017a). In this case, the demand for transformation of glycerol tovaluableadded chemicals has attracted increasing attention in recent years (Kim et al. 2017b; Li and Zaera 2015; Dodekatos, Schünemann, and Tüysüz 2018a). Various catalytic conversion pathways have been widely investigated to produce a number of products, such as glyceraldehyde (GLAD), dihydroxyacetone, glyceric acid (GLA), hydroxypyruvic acid, tartronic acid (TA), glycolic acid (GA), and oxalic acid (OA) (Lei et al. 2014). In particular, among these oxidation produces, GLA is an important substance that can be used in biochemical research, such as muscle physiology, pharmaceutical, organic synthesis, and so on (Wang et al. 2018). However, the present methods of mainly manufactured GLA are far from satisfactory to meet the market demand, and the price of GLA is expensive (Xiang and Davis 2010). Therefore, it is of great significance to develop a cheap and efficient method for selective oxidation of GLY to GLA. In these processes, the activity and selectivity of catalyst are highly dependent on the metal species, dispersion degree, particle size, pH of the reaction solution, and nature of the support material (Kim et al. 2014; Dodekatos et al. 2018a, 2018b).