Biodiesel synthesis system

Deep eutectic solvents based on choline acetate (ChOAc), which have lower viscosities as compare to the ChCl/Urea eutectic mixture, have been also used as reaction media in several biocatalyzed transesterification reactions. In this sense, Zhao et al. reported the transesterification of ethyl sorbitate with 1-propanol by the lipase Novozym 435 Candida Antarctica lipase B immobilized on acrylic resins), achieving high initial rates (1 pmolmin g ) and selectivity (99%). Furthermore, in a model biodiesel synthesis system, the authors examined the transeterification of the lipid Miglyol oil 812 (a mixture of triglycerides of caprylic acid (C8) and capric acid (CIO)) with methanol, catalyzed by Novozym 435 in ChOAc/Gly (1 1.5 molar ratio). The biocatalytic reaction was very rapid in this eutectic mixture, with 97% conversion achieved after only 3 hours. 

The reader should also be aware that some information provided in this section and in the sections below does not directly address the subject of biodiesel synthesis. Some discussions, for instance, are about the transesterification of simple esters or the production of monoglycerides by transesterification of vegetable oils nevertheless, the information provided is relevant to the topic of biodiesel synthesis since knowledge of catalyst reactivity in these systems is directly applicable to reactions involving TGs and FFAs. 

Rosset et al. (2013) reported biodiesel production by esterification of oleic acid with aliphatic alcohols using immobilized Candida antarctica lipase, showing high yields of biodiesel (above 90%) in less than 24 h with ethanol, n-propanol and n-butanol whereas with methanol, the enzyme was inactive after ten ( cles of reaction. In another report, Yin et al. (2013) studied an efficient bifimctional catalyst lipase/organophosphonic acid-functionalized silica (SG-T-P-LS) for biodiesel synthesis by esterification of oleic acid with ethanol. In this system, the process had a conversion ratio reaching 89.94 0.42% under the conditions that the ethanol/acid molar ratio was 1.05 1 and the SG-T-P-LS to free fatty acid weight ratio was 14.9 wt.% at 28.6 C (Yin et al., 2013). 

Compared to the base-catalyzed synthesis of biodiesel, fewer studies have dealt with the subject of acid-catalyzed transesterification of lipid feedstocks. Among acid catalysts, sulfuric acid has been the most widely studied. In the previously mentioned work of Freedman et al., the authors examined the transesterification kinetics of soybean oil with butanol using sulfuric acid. The three reaction regimes observed (in accordance with reaction rate) for base-catalyzed reactions were also observed here. A large molar ratio of alcohol-to-oil, 30 1, was required in this system in order to carry out the reaction in a reasonable time. As expected, transesterification followed pseudo-first-order kinetics for the forward reactions (Figure 2), while reverse reactions showed second-order kinetics. 

Li et al. (2007) reported the use of dry biomass, Rhizopus oryzae (R. oryzae) IF04697, whole cell-catalyzed methanolysis of soybean oil for biodiesel (methyl ester) in rm-butanol system. Changing one separate factor at a time (COST), live-level-four-factor Central Composite Design (CCD) were used to evaluate the effects of synthesis conditions, such as tert-butanol to oil volume ratio, methanol to oil molar ratio, water content, and dry biomass amount. Biodiesel yields of 72% were obtained under the optimal conditions using the proposed model for prediction. 

The first part of this chapter is intended to survey recent literature on new catalytic materials because the development of new types of metal oxides and layered- and carbon-based materials with different morphologies opens up novel acid-base catalysis that enables new type of clean reaction technologies. Mechanistic considerations of acid- and base-catalyzed reactions should result in new clean catalytic processes for Green and Sustainable Chemistry, for example, transformations of biorenewable feedstock into value-added chemicals and fuels [21-35]. The latter part of this chapter, therefore, focuses on biomass conversion using solid acid and base catalysts, which covers recent developments on acid-base, one-pot reaction systems for carbon-carbon bond formations, and biomass conversion including synthesis of furfurals from sugars, biodiesel production, and glycerol utilization. 

Tongboriboon K, Cheirsilp B, H-kittikun A. Mixed Upases for efficient enzymatic synthesis of biodiesel from used palm oil and ethanol in a solvent-free system.J Mol Catal B Enzym 2010 67 52-9. 

Biomass-based alcohols could also be employed directly as substrates in N-alkylation reactions, making the hydrogen autotransfer method more practical. In 2011, Martin-Matute and co-workers reported a [Cp IrCl2]2-catalyzed method for synthesis of secondary aminosugars from primary aminosugars with simple alcohols and primary carbohydrate alcohols (Eq. 20) [106]. In 2009, Stephens, Marr and coworkers reported that a one-pot bio- and chemo-catalytic process could be used for direct conversion of crude glycerol from biodiesel production to valuable secondary amines in a biphasic system without intermediate separation of 1,3-propanediol... 

P. Lozano,. M. Bernal, M. Vaultier, Towards continuous sustainable processes for enzymatic synthesis of biodiesel in hydrophobic ionic liquids/supercritical carbon dioxide biphasic systems, Fuel 90 (2011) 3461-3467. 

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