Catalyst continued sodium methoxide

The methanol carbonylation is performed ia the presence of a basic catalyst such as sodium methoxide and the product isolated by distillation. In one continuous commercial process (6) the methyl formate and dimethylamine react at 350 kPa (3.46 atm) and from 110 to 120°C to effect a conversion of about 90%. The reaction mixture is then fed to a reactor—stripper operating at about 275 kPa (2.7 atm), where the reaction is completed and DMF and methanol are separated from the lighter by-products. The cmde material is then purified ia a separate distillation column operating at atmospheric pressure. 

Although interesterification will occur in the absence of added catalysts at sufficiently high temperatures, catalysts are employed by industry to speed this reaction, reducing reaction time and the sample degradation that occur at elevated temperatures. The most commonly used inorganic catalysts are alkaline ones such as sodium methoxide, sodium ethoxide, sodium or potassium metal, and alloys of sodium and potassium. Catalyst concentrations of 0.05% to 0.1% are employed. As the catalysts will react with water, free fatty acids, and oxidized compounds, it is important to use clean, dry feedstocks. Reaction temperatures are generally kept below 100°C. The reactions can be mn in batch or continuous formats. In batch mode, the reaction times are typically less than an hour. 

This approach, as exemplified by the work of Wehman et al., appears ripe for commercialization. Drawbacks of the reaction are the need for three equivalents of carbon monoxide and relatively large amounts of noble metal catalysts. The use of relatively high levels of catalyst is not a problem if the catalyst can be used over a long time period and has good activity, as in a column in a continuous process. A variant (2.22) using a 1 1 molar ratio of nitroben zene to aniline eliminates the need for the noble metal catalyst.57 The catalyst is a mixture of sulfur, sodium methoxide, and ammonium metavanadate. 

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. 

Polyvinyl acetate is hydrolyzed to polyvinyl alcohol in a continuous belt or extrusion process using sodium or potassium hydroxide, methoxide, or ethoxide catalysts. The hydrolysis process is complicated on a commercial scale due to a significant increase in viscosity that accompanies conversion. Following hydrolysis, the polyvinyl alcohol gel is ground, dried, ground, sized, and packaged [53]. 

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