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Transesterification of triglyceride

Chemoenzymatic synthesis of alkyds (oil-based polyester resins) was demonstrated. PPL-catalyzed transesterification of triglycerides with an excess of 1,4-cyclohexanedimethanol mainly produced 2-monoglycerides, followed by thermal polymerization with phthalic anhydride to give the alkyd resins with molecular weight of several thousands. The reaction of the enzymatically obtained alcoholysis product with toluene diisocyanate produced the alkyd-urethane. [Pg.226]

Biodiesel is a fuel derived from renewable natural resources such as soybean and rapeseed and consists of alkyl esters derived from transesterification of triglycerides with methanol. In spite of all the advantages of biodiesel, such as low emissiotts, biodegradability, non-toxicity, and lubricity, the major hurdle in penetration of biodiesel is its high cost because of the expensive food grade refined vegetable oil feedstock. [Pg.279]

Attention is drawn to the hazards involved in the use of perchloric acid in a published method [1] for transesterification of triglycerides with methanol. Alternative acid catalysts and safety precautions are suggested [2],... [Pg.1360]

The rates of transesterification of triglycerides to methyl esters, efficiently catalyzed by boron carbide (B4C), were, on the other hand, faster under microwave conditions, probably because of superheating of the boron carbide catalyst, which is known to be a very strong absorber of microwaves [40], Scheme 10.3. Yields of methyl ester of up to 98% were achieved. [Pg.352]

Transesterification of triglycerides in the presence of B4C [40]. The rate enhancement was not assessed quantitatively. Reaction conditions a stirred multi-mode tank reactor, no solvent. [Pg.363]

Fatty Acid Esters and Fatty Alcohols Fatty acid esters are obtained by transesterification of triglycerides (vegetable oils) or by esterification of fatty acid with alcohol or polyols. Fatty alcohols are obtained by hydrogenation of esters on metal catalysts. Fatty acid esters and fatty alcohols are useful platform molecules to prepare surfactants, emulsifier, lubricants and polymers. [Pg.62]

Most biodiesel is produced today through transesterification of triglycerides of refined edible oils (Scheme 10.1). [Pg.326]

The use of heterogeneous basic catalysts for the transesterification of triglycerides has long been considered the main tool to reduce processing costs in the production of biodiesel, as it would lead to simplified operations and eliminate waste streams. [Pg.328]

Scheme 10.2 Homogeneous acid-catalyzed reaction mechanism for the transesterification of triglycerides (1) protonation of the carbonyl group by the acid catalyst (2) nucleophilic attack of the alcohol, forming a tetrahedral intermediate (3) proton migration and breakdown of the intermediate. The sequence is repeated twice. Scheme 10.2 Homogeneous acid-catalyzed reaction mechanism for the transesterification of triglycerides (1) protonation of the carbonyl group by the acid catalyst (2) nucleophilic attack of the alcohol, forming a tetrahedral intermediate (3) proton migration and breakdown of the intermediate. The sequence is repeated twice.
Catalysts able to promote both transesterification of triglycerides and esterification of FFAs in an oil or fat are still rare and up to now none of them have found a commercial application. Thus far it seems that a moderate to high concentration of strongly acidic sites and a hydrophobic surface are mandatory to achieve good conversions in simultaneous esterification and transesterification reactions, but more research and creative thinking are still needed in this area. [Pg.342]

The transesterification of triglycerides with methanol is a simple and straightforward process. It is commercially practiced worldwide in the production of FAMEs, which have become popular as a replacement for diesel known as biodiesel . The process consists of three separate equilibrium reactions that can be catalyzed by both acids and bases. (4) The overall process is described in Figure 3. Phase separation of the glycerin is the predominant driving force for this process. [Pg.379]

Figure 4 Homogeneous base-catalyzed reaction mechanism for the transesterification of triglycerides... Figure 4 Homogeneous base-catalyzed reaction mechanism for the transesterification of triglycerides...
In order to enhance the potential of synthetic reactions of lipids and the transesterification in organic solvents, a fungal lipase from Phycomyces nites was chemically modified. The promotion of dispersibility in orgaiuc solvents resulted in a much higher reactivity. Chemically modified lipases showed higher reactivity than unmodified lipase when they were utilized for the transesterification of triglycerides and other lipids. The initial rate of transesterification in organic solvents by modified lipase was 40 times faster than that of unmodified lipase. Chemically modified lipase was also found applicable for the syndesis of other fatty acids esters. [Pg.170]

Methanol and Triglycerides. Transesterification of triglycerides in methanol using HCIO4 is hazardous.18... [Pg.435]

A catalyst-free supercritical methanol method for biodiesel fuel production was proposed with the optimum conditions of 350°C, 20 MPa, a molar ratio of 42 in methanol, and a 4-min treatment period (12-13). This method has been proved to produce a high yield, because of simultaneous reactions of transesterification of triglycerides and methyl esterification of free fatty acids (10). The only shortcoming of this one-step method is that it requires a severe reaction condition compared with the conventional commercial method with acid or alkaline catalyst. Consequently, our method would require a special alloy to cover the high temperature and high pressure of the reaction system. [Pg.782]

Fig. 5. Comparison in yield of methyl esters between transesterification of triglycerides and methyl esterification of fatty acids by supercritical methanol treatment at various temperatures. , Transesterification at 270°C A, transesterification at 300°C , transesterification at 350°C O, methyl transesterification at 270°C A, methyl transesterification at 300°C , methyl transesterification at 350°C. Fig. 5. Comparison in yield of methyl esters between transesterification of triglycerides and methyl esterification of fatty acids by supercritical methanol treatment at various temperatures. , Transesterification at 270°C A, transesterification at 300°C , transesterification at 350°C O, methyl transesterification at 270°C A, methyl transesterification at 300°C , methyl transesterification at 350°C.
Figure 5 shows a comparison of the yields of methyl esters between transesterification of triglycerides (rapeseed oil) and methyl esterification of fatty acids by supercritical methanol at various temperatures. At 350°C, both reactions could produce very similar results. At 300°C, transesterification produced about 90% methyl esters at 12 min of treatment, whereas methyl esterification resulted in a complete conversion. When triglycerides were transesterified at 270°C, a plateau was reached at about 40 min of treatment with a yield of about 76%. However, much higher yield could be achieved by methyl esterification at 20 min of treatment. These results, therefore, indicate that the reaction rate in methyl esterification is higher than that in transesterification. [Pg.787]

Figure 6.6 Transesterification of triglycerides to methyl ester and glycerol... Figure 6.6 Transesterification of triglycerides to methyl ester and glycerol...
Fukuda et al. (2001) reported enzymatic transesterification using lipase has become more attractive for biodiesel production, since the glycerol produced as a by-product can easily be recovered and the purification of FAME is simple to accomplish. Lipases shown in Table 9.1 can effectively catalyze the transesterification of triglycerides and the problems mentioned above can be circumvented by using the enzyme. [Pg.164]

Biguanides, which are even stronger bases, open new perspectives but they require special preparations. Novel syntheses of poly-N-alkylated biguanides have been devised from carbodiimides, and recent examples of catalyses with soluble and immobilised guanidines and biguanides are presented with emphasis on the transesterification of triglycerides from vegetable oils. [Pg.133]

These catalysts were found to be efficient catalysts in the transesterification of triglycerides of rapeseed and soyabean oils with methanol, as shown below,17 and recycling experiments were performed (Figure 13). [Pg.139]


See other pages where Transesterification of triglyceride is mentioned: [Pg.175]    [Pg.353]    [Pg.62]    [Pg.64]    [Pg.46]    [Pg.326]    [Pg.14]    [Pg.53]    [Pg.13]    [Pg.170]    [Pg.50]    [Pg.401]    [Pg.402]    [Pg.417]    [Pg.139]    [Pg.373]    [Pg.236]    [Pg.360]    [Pg.1703]    [Pg.8]    [Pg.246]    [Pg.47]   
See also in sourсe #XX -- [ Pg.174 , Pg.175 ]




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