Methanol biodiesel production using

In this study, we have attempted to determine the optimal conditions for enzyme-catalyzed methanolysis of biodiesel production, using rapeseed oil with methanol and Novozym 435. 

Saka, S., Isayama, Y, Ilham, Z. and Jiayu X. 2010. New process for catalyst-free biodiesel production using subcritical acetic acid and supercritical methanol. Fuel. 89(7) 1442-1446. 

Farobie, O., Matsumura, Y., 2015a. A comparative study of biodiesel production using methanol, ethanol, and tert-butyl methyl ether (MTBE) under supercritical conditions. Bioresource Technology 191, 306—311. 

Figure 7 depicts a simplified block flow diagram (BFD) for a typical biodiesel production process using base catalysis. In the first step, methanol and catalyst (NaOH) are mixed with the aim to create the active methoxide ions (Figure 4, step 1(b)). Then, the oil and the methanol-catalyst solution are transferred to the main reactor where the transesterification reaction occurs. Once the reaction has finished, two distinct phases are formed with the less dense (top) phase containing the ester products and unreacted oil as well as some residual methanol, glycerol, and catalyst. The denser (bottom) layer is mainly composed of glycerin and methanol, but ester residues as well as most of the catalyst, water, and soap can also be found in this layer. 

Figure 9 shows a schematic process of biodiesel production by the two-step supercritical methanol method. Several advantages have been attributed to the two-step reaction method. At temperature of 270°C, a common type of 316 stainless steel can fulfill the requirements of good corrosion resistance and cover the reaction condition (5). Energy requirements may be less because mild reaction conditions for hydrolysis and methyl esterification are employed, whereas high-temperature treatment causes operational and equipment problems with, in some cases, the formation of undesirable degradation products. In addition, a reaction temperature of 270°C is commonly used in industries, so such a reaction condition is applicable for commercial applications. 

Fatty acids are obtained by fat splitting using water (hydrolysis), methanol (metha-nolysis), and base (saponification) of amines (aminolysis). Splitting with water or methanol can be considered transesterification because glycerol is liberated. The methanolysis is the reaction taking place in biodiesel production as the resulting product is called fatty acid methyl ester. 

As discussed in a previous section, metal oxides represent an important class of materials exhibiting a broad range of properties from insulators to semiconductors and conductors and have found applications as diverse as electronics, cosmetics and catalysts. Metal oxides have been widely used in many valuable heterogeneous catalytic reactions. Typical metal oxide-catalyzed reactions, including alkane oxidation, biodiesel production, methanol adsorption and decomposition, destructive adsorption of chlorocarbons and warfare agents, olefin metathesis and the Claisen-Schmidt condensation will be briefly discussed as examples of metal oxide-catalyzed reactions. 

Waste oils, from restaurants and household disposals and being creating serious problems of environmental control and food safety, have been considered as good raw material for biodiesel production. Immobilized Candida antarctica lipase was found to be effective for the methanolysis of waste oil. A three-step methanolysis protocol could be used to protect lipase from inactivation by methanol. Compared with one-step reaction, it needs a longer time to reach the reaction equilibrium. So, efforts should be made to increase enzymatic reaction rate. Reports on the enhancement of the activity of certain enzymes by applying ultrasonic irradiation on the enzymes led us to investigate its effects on the enzymatic transesterification of waste oil to biodiesel in a solvent free system. 

In this study, we have attempted to evaluate the efficacy of a technique for the production of the methyl ester of rapeseed oil via enzyme-catalyzed transesterifications using tert-butanol, a moderately polar organic solvent. We conducted experiments involving the alteration of several reaction conditions, including reaction temperature, methanol/oil molar ratio, enzyme amount, water content, and reaction time. The selected conditions for biodiesel production were as follows reaction temperature 40 °C, Novozym 435 5% (w/w), methanol/oil molar ratio 3 1, water content 1% (w/w), and 24h of reaction time. Under these reaction conditions, a conversion of approximately 76.1% was achieved. Further studies are currently underway to determine a method by which the cost of fatty acid methyl ester production might be lowered, via the development of enzyme-catalyzed methanolysis protocols involving a continuous bioprocess. 

As the methanol-to-oil ratio increases, the biodiesel production increases in a membrane reactor. The common molar ratio of methanol to oil used in biodiesel production is 24 1 in a membrane reactor in which the separation is based on oil droplet size (Baroutian et al., 2011 Cao et al., 2008a Cheng et al., 2010). 

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). 

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