Fatty acid methyl esters catalysts

Hydrogenation of Fatty Acid Methyl Esters The hydrogenolysis of fatty acid methyl esters into the corresponding fatty alcohols and methanol is performed at 200-300°C and a H2 pressure of 200-300 bar with the aid of copper oxide/chromium oxide catalysts (Adkins catalysts). Three different procedures are applied [39 a-c] ... 

The transesterification of fats and fatty oils by methanol into fatty acid methyl esters proceeds at 50-70°C without pressure. The deacidified fat is stirred for a short period with an excess of methanol and 0.1-0.5% caustic alkali as catalyst. On standing the reaction mixture separates forming a bottom layer of glycerin and a top layer of fatty acid esters. 

In our first experiment we decided to test the conversion of sunflower oil into biodiesel (16). Treatment of sunflower oil (1) with NaOMe in MeOH results in formation of a mixtme of fatty acid methyl esters (FAME), also known as biodiesel, and glycerol (2) (Figme 4.3). The reaction was performed with a six-fold molar excess of methanol with respect to sunflower oil at elevated temperatures (60°C) using a basic catalyst (NaOMe, 1% w/w with respect to sunflower oil). The CCS was equipped with a heating jacket to ensure isothermal conditions. The sunflower oil was preheated to 60°C and was pumped at 12.6 ml/min into one entrance of the CCS. Subsequently, a solution of NaOMe in MeOH was introduced through the other entrance at a flow rate of 3.1 ml per minute. After about 40 minutes, the system reaches steady state and the FAME containing some residual sunflower oil is coming... 

Fatty acid methyl esters (FAME) are currently manufactured mainly by trans-esterification with an alcohol, using a homogeneous base catalyst (NaOH/KOH). Methanol is more suitable for biodiesel manufacturing, but other alcohols can in principle also be used, depending on the feedstock available. The... 

Biodiesel (fatty acid methyl ester (FAME)) production is based on transesterification of vegetable oils and fats through the addition of methanol (or other alcohols) and a catalyst, giving glycerol as a by-product (which can be used for cosmetics, medicines and food). Oil-seed crops include rapeseeds, sunflower seeds, soy beans and palm oil seeds, from which the oil is extracted chemically or mechanically. Biodiesel can be used in 5%-20% blends with conventional diesel, or even in pure form, which requires slight modifications in the vehicle. 

Parrish (1977) reviewed the research and development of lactose ester-type surfactants carried out by Scholnick and his colleagues (Scholnick et al. 1974, 1975 Scholnick and Linfield 1977). Their initial attempts to form lactose esters followed the same transesterification procedures that had been used with sucrose (a fatty acid methyl ester in N,N-dimethylformamide with potassium carbonate as the catalyst). Their successful approach was the reaction of lactose in N-methyl-2-pyrrolidone as the solvent with fatty acid chlorides, resulting in yields of 88 to 95% for esters of lauric, myristic, palmitic, stearic, oleic, and tallow fatty acids. The principal product was the monoester, which is important for detergent use, since diesters and higher esters of lactose are not water soluble. 

There are basically two mechanisms to convert the fatty acids in a complex lipid to fatty acid methyl esters (FAMEs) methylation following hydrolysis of the fatty acids from the complex lipids, or direct transesterification. The first mechanism involves saponification (alkaline hydrolysis) in which the ester bond is cleaved between the fatty acid and the glycerol moiety (e.g., triacylglycerols and phospholipids) under heat and in the presence of an alkali (usually sodium hydroxide), followed by methylation performed in the presence of an acidic catalyst in methanol. Direct transesterification is usually a one-step reaction involving alkaline or acidic catalysts. 

In homogeneous catalysis, the catalyst is in the same phase as the reactants and products. Here we will concentrate on homogeneous catalysis in the liquid phase. In the classic case, the reactant (also called the substrate) molecules and the catalyst are reacted in a solvent. For example, the transesterification of fatty acid triglycerides with methanol (Figure 1.10) is catalyzed by hydroxide (OH-) ions. This is an important process for making fatty acid methyl esters which are then used as biodiesel. 

Fatty acid methyl esters (FAMEs) show large potential applications as diesel substitutes, also known as biodiesel fuel. Biodiesel fuel as renewable energy is an alternative that can reduce energy dependence on petroleum as well as air pollution. Several processes for the production of biodiesel fuel have been developed. Transesterification processes under alkali catalysis with short-chain alcohols give high yields of methyl esters in short reaction times. We investigated transesterification of rapeseed oil to produce the FAMEs. Experimental reaction conditions were molar ratio of oil to alcohol, concentration of catalyst, type of catalyst, reaction time, and temperature. The conversion ratio of rapeseed oil was enhanced by the alcohohoil mixing ratio and the reaction temperature. 

In the methyl ester route (Figure 1), refined triglycerides are reacted with methanol in the presence of a sodium methoxide catalyst to form the corresponding fatty acid methyl esters and glycerine (2). 

In an alcoholysis reaction for production of BDF from vegetable oil, triglyceride (the main component of vegetable oil) is reacted with methanol and fatty acid methyl ester (FAME) and glycerol are formed (Fig. 5.1), and the FAME is used as BDF. In a conventional process for production of BDF, alkaline catalysts such as NaOH and KOH are used to promote the reaction. 

MeSOj radicals also act as the catalyst for the cis-tmns isomerization of several Z- and -monounsaturated fatty acid methyl esters (see Sec. 2.2.4) in homogeneous solutions. 

Mazzocchia, C. G. Modica A. Kaddouri R. Nannicini. Fatty acid methyl esters synthesis from triglycerides over heterogeneous catalysts in the presence of microwaves. C.R Chimie 2004, 7, 601-605. 

Conventional technology of the hydrogenolysis of fatty acid methyl esters to the corresponding fatty alcohols uses copper chromite or zinc chromite based catalysts and the manufacturing process requires high pressures (200-300 bar) and temperatures (250-300 °C). The activity of copper chromite catalysts was significantly increased by the addition of zinc. ... 

Hydrogenations in supercritical fluids are close to industrial-scale application. In the process developed by Harrod and colleagues [15], the hydrogenation of fatty acid methyl esters is carried out in propane, because the solubilities of the esters in supercritical CO2 are too low. In propane, the reaction can be carried out with only one supercritical phase contacting the solid catalyst, and with enough hydrogen to ensure an extremely fast and selective reaction. 

The catalyst used is sodium hydroxide dissolved in methanol. Water is formed in the course of alcoxide formation. In the presence of water, the sodium hydroxide present reacts very quickly with fatty acid methyl esters to form sodium soaps. Under these conditions, the soaps formed are not effective catalysts. 

Another area of major indnstrial importance is the production of oleochemical raw materials such as fatty acids, fatty acid methyl esters, fatty alcohols, and glycerol. The company Henkel is the world s largest processor of renewable fats and oils, with a capacity of 10 t. Tailor-made catalysts are used in most oleochemical reactions. 

Fatty acid methyl esters are now the main intermediates in oleochemistry. Epox-idation can be considered as a transformation currently applied to triglycerides that is easy to perform on an industrial scale, compared with the production process for fatty alcohol. Therefore, why should epoxidized fatty acid methyl esters not become one of the commodities of the future The commercial development of these compounds requires easy, environmentally friendly (e.g., avoiding catalyst use) routes of low production cost as well as identified industrial outputs. Such considerations were taken into account in this study both rapeseed methyl esters (RME) and high-oleic sunflower methyl esters (HOSME) were used as starting materials. 

The principles of biodiesel synthesis are relatively simple oleochemical reactions (see Chapter 9.1) and have been known and applied for many decades (Figure 8.5)." The basic technology consists in a catalyst induced transesterification of a vegetable oil in a batch, semi-batch or continuous process to create a fatty acid methyl ester (FAME). The catalyst used is a strong base,... 

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