Catalyst alkaline, sodium hydroxide/methylate

After the completion of the reduction the catalyst is removed by filtration and the alcohol is evaporated on the steam bath. To the resulting syrupy solution is added about 85 ml. of 3 A hydrochloric acid (sufficient to make the solution acid to Congo red paper). The solution is extracted with three 50-ml. portions of ether. The aqueous layer is made alkaline with 50 ml. of 6 iV sodium hydroxide, and the amine layer is separated. The aqueous layer is extracted with three 50-ml. portions of ether, and the extracts are combined with the amine layer. The ether solution is dried overnight with solid potassium hydroxide and is filtered to remove suspended matter the flask is rinsed with 25 ml. of ether. The ether is removed on a steam bath, and the amine is distilled under reduced pressure from a modified Claisen flask having a 15-cm. indented column. The N-methyl-2,3-dimeth-oxybenzylamine distils at 120-124°/8 mm. and is obtained in a yield of 39-42 g. (86-93%) (Notes 6 and 7). 

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 this case, a new ester is formed. Generally, alkaline catalysts are used with sodium methylate said to be the most effective, although sodium hydroxide can also be used. 

Conventional industrial biodiesel processes are based on homogeneous alkaline catalysts. Sodium hydroxide or sodium methylate are the most often used catalyst in... 

In 1989, the concept of ethoxylating methyl esters, which do not carry a labile hydrogen, was introduced by Hoechts [2] and Henkel [3]. Hoechst demonstrated the ethoxylation of esters was chemically feasible using catalysts based on alkali and alkaline earth metals (e.g., sodium hydroxide, sodium methoxide, barium hydroxide, etc.). Henkel demonstrated the feasibility of using calcined hydrotalcite (aluminum-magnesium hydroxycarbon-ates) for the reaction. Reactivities and conversions with these catalysts, however, were found to be too low for commercial application. 

In this case, a new ester is formed. Generally, alkaline catalysts are used with sodium methylate said to be the most effective, although sodium hydroxide can also be used. Transesterification is an equihbrium reaction. To shift the reaction to the right, it is necessary to use a large excess of alcohol or to remove one of the products from the reaction mixture. The second option is preferred where feasible, as in this way, the reaction can be driven to completion. 

The exothermic reaction is carried mostly out batchwise at elevated temperature ( 150 °C) and 5-10 bar (0.5-1 MPa) pressure with alkaline (sodium or potassium hydroxide or methylate) or acidic catalysts ... 

The process involves reacting the degummed oil with an excess of methyl alcohol in the presence of an alkaline catalyst such as sodium or potassium methoxide, reaction products between sodium or potassium hydroxide and methyl alcohol. The reaction is carried out at approximately 150°F under pressure of 20 psi and continues until trans-esterification is complete. Glycerol, free fatty acids and unreacted methyl alcohol are separated from the methyl ester product. The methyl ester is purified by removal of residual methyl alcohol and any other low-boiling-point compounds before its use as biodiesel fuel. From 7.3 lb of soybean oil, 1 gallon of biodiesel fuel can be produced. See FIGURE 12-5. 

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