Reaction with lauric acid

Another ester synthesis employs the reaction of a long-chain ketone and pentaerythritol in xylene or chlorobenzene (14). Mixed esters have been produced using mixed isostearic and cyclohexane carboxyUc acids in trihromophosphoric acid, followed by reaction with lauric acid (15). 

By the enzymatic esterification of diglycerol with lauric acid, the corresponding monolaurate ester is obtained [84]. This is an important industrial reaction for the cosmetic, pharmaceutical and feed industries, since this ester is used as biodegradable non-ionic surfactant. In recent years, the synthesis of this and other polyglycerols with fatty acids has attracted growing interest in industry, leading also to a demand for enantiomerically and isomerically pure products. 

Jacobs and coworkers reported the catalytic activity of a mesoporous silica-supported sulfonic sites in the esterification of sorbitol with lauric acid [130]. This reaction affords in a one step process the dilauryl isosorbide (dehydration of sorbitol/esterification). In contrast to zeolites, it is found that mesoporous silica-supported sulfonic sites afford the corresponding dilauryl isosorbide with 95% selectivity at 33% conversion (Scheme 13). 

Another method of prepn of acetyl laurin is to treat triacetin (see under Acetins), in the presence of an alkaline catalyst with lauric acid to replace one of the acetyl groups. The AcOH produced by the reaction can be removed by azeotropic distn using sufficient hydrocarbon solvent to maintain the distn temp at ca 200°... 

Enzyme activity was determined as the initial rates in esterification reactions between lauric acid and propanol at a molar ratio of 1 3, a temperature of 60°C, and an enzyme concentration of 5 wt% in relation to the substrates. At the beginning of the reaction, samples containing the mixture of lauric acid and propanol were collected and the lauric acid content was determined by titration with 0.04 N NaOH. After the addition of the enzyme to the substrates, the mixture was kept at 60°C for 15 min. Then, lauric acid consumption was determined. 

Figure 13.3 shows the profiles of the DBSA-catalysed reaction of lauric acid with 3-phenyl-1-propanol (1 1) at 40°C in water (closed circle). The reaction reached its maximum yield of 84% in 170 hours. We also conducted hydrolysis of the corresponding ester (open square). Both esterification and hydrolysis finally led to the same composition of the reaction mixture, indicating that the reaction reached its equilibrium position. 

The reaction of esterification of glycidol with lauric acid (Fig. 13) is known to occur in presence of a base or in presence of a Lewis acid. This reaction leads to the formation of monoglycerides, useful emulsifiers in most processed fatty or oily foods, as well as in cosmetic and pharmaceutical products. However, the nucleophilic attack of the oxygen atom of the carboxylic function whether rai the a-C or p-C of the epoxide can produce two isomers. Generally the selectivity of the reaction reflects preferred a position... 

Table 3.6 and Scheme 3.31, in the model reaction of lauric acid with 3-phenyl-1-propanol, commercially available DOWEX 500W-X2 (H+-form, 9) did not promote esterification. The result indicates that a highly hydrophobic nature of the polymer-supported catalysts is important for activity in the dehydration reaction in water. It was found that resin 9 swelled significantly in water due to its high sulfonic acid content. On the other hand, both 11 and 12 scarcely swelled in water but worked as efficient catalysts. Resin 11 was easily recovered by simple filtration after the esterification was complete, and the catalyst could be continuously reused at least four times without loss of catalytic activity (Scheme 3.32). 

FIGURE 13.4 Dependence of the initial velocity Vq of the esterification reaction of lauric acid with hexanol ( ) and decanol (O) catalyzed by P. simplicissimum lipase in AOT/ isooctane microemulsion, as a function of the alcohol concentration. (From Stamatis, H. Enzymatic conversion of amphiphilic substrates in microemulsions, PhD thesis, University of Patras, Patras, 1996). 

Hydroxylations of fatty acids by cytochrome P450119 compound increase in rate with chain length and show no intermolecular KE in buffer. With glycerol, the rate of reaction of lauric acid increases, and a KIE is observed. Reversible formation of a non-reactive complex of a fatty acid with the cytochrome and its isomerization to a reactive one is proposed. A tandem oxidative cyclocondensation process is reported for the synthesis of 3,4-dihydropyrimidin-2(l//)-one or -thione derivatives from primary aryl alcohols, -keto esters, and urea or thiourea in the presence of aluminium nitrate nonahydrate as oxidant catalyst. ... 

The esterification of a racemic alcohol with lauric acid proceeds with high enantio-selectivity only after imprinting with the opticaUy active substrate and coating of the lipase with synthetic glycolipids [79]. In Scheme 9 are shown other examples of the same reaction that successfully applies to cyclic alcohols [80] and diols as well [81]. 

Many of the surfactants made from ethyleneamines contain the imidazoline stmcture or are prepared through an imidazoline intermediate. Various 2-alkyl-imidazolines and their salts prepared mainly from EDA or monoethoxylated EDA are reported to have good foaming properties (292—295). Ethyleneamine-based imida zolines are also important intermediates for surfactants used in shampoos by virtue of their mildness and good foaming characteristics. 2- Alkyl imidazolines made from DETA or monoethoxylated EDA and fatty acids or their methyl esters are the principal commercial intermediates (296—298). They are converted into shampoo surfactants commonly by reaction with one or two moles of sodium chloroacetate to yield amphoteric surfactants (299—301). The ease with which the imidazoline intermediates are hydrolyzed leads to arnidoamine-type stmctures when these derivatives are prepared under aqueous alkaline conditions. However, reaction of the imidazoline under anhydrous conditions with acryflc acid [79-10-7] to make salt-free, amphoteric products, leaves the imidazoline stmcture essentially intact. Certain polyamine derivatives also function as water-in-oil or od-in-water emulsifiers. These include the products of a reaction between DETA, TETA, or TEPA and fatty acids (302) or oxidized hydrocarbon wax (303). The amidoamine made from lauric acid [143-07-7] and DETA mono- and bis(2-ethylhexyl) phosphate is a very effective water-in-od emulsifier (304). 

Therefore a special N-containing ether carboxylate was developed [36] with a high melting point ( 90°C) with a good foam and low hard water sensibility. This is obtained by condensation of a fatty acid (e.g., lauric acid) with diglycolamine, followed by carboxymethylation with NaOH and SMCA, washing out of the reaction mixture with a aqueous solution of a strong acid, separation of the oil layer, and neutralization with NaOH or KOH. The result is an ether carboxylate with exactly 2 EO units with the structure ... 

Recently, an environmentally benign and volume efficient process for enzymatic production of alkanolamides has been described where CALB catalyzes the amidation of lauric acid and ethanolamine in the absence of solvent, at 90 °C, to keep the reactants in a liquid state and to remove the water [18]. The enzyme was both very active and stable under the reaction conditions, with about half of the activity remaining after two weeks, obtaining the final amide with a 95% yield (Scheme 7.6). 

As seen in Fig. 4.8, the adsorption of lauric acid (C12) is slow because of slow transport (diffusion) at concentrations smaller than 10 6 M. In case of Na+-caprylate (Cs) the attainment of equilibrium is delayed most probably by structural rearrangement at the surface. In case of anions, such association reactions are slower than with free acids. 

This enzyme [EC 1.14.15.3], also known as alkane 1-monooxygenase, lauric acid ca-hydroxylase, fatty acid hydroxylate fatty acids in the [Pg.47]

The failure to fit the data over the complete conversion range from 0 to 100% to a third-order plot has sometimes been ascribed to failure of the assumption of equal functional group reactivity, but this is an invalid conclusion. The nonlinearities are not inherent characteristics of the polymerization reaction. Similar nonlinearities have been observed for nonpolymerization esterification reactions such as esterifications of lauryl alcohol with lauric or adipic acid and diethylene glycol with caproic acid [Flory, 1939 Fradet and Marechal, 1982b]. 

Another method of achieving the desired molecular weight is by addition of a small amount of a monofunctional monomer, a monomer with only one functional group. Acetic acid or lauric acid, for example, are often used to achieve molecular weight stabilization of polyamides. The monofunctional monomer, often referred to as a chain stopper, controls and limits the polymerization of bifunctional monomers because the growing polymer yields chain ends devoid of functional groups and therefore incapable of further reaction. Thus, the use of benzoic acid in the polyamide synthesis yields a polyamide (XI) with phenyl end groups that are unreactive toward polymerization. 

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. 

Write a balanced equation for the condensation reaction in which lauric acid, palmitic acid, and stearic acid combine with glycerol to form a triglyceride. 

All experiments were performed in a 20-mL open batch reactor with constant stirring and temperature control. The reaction system contained a mixture of lauric acid and glycerol and the biocatalyst Lipozyme IM-20. The reaction s progress was followed by withdrawing 20-pL aliquots at various time intervals and analyzing themby GC, as previously described. 

The surface reactions with H20 or with alizarin may be used for estimating the surface areas of such salt layers (140). Estimations of surface areas may in other cases also successfully be performed with the aid of the physical adsorption of other molecules with peripheric dipoles, such as lauric acid molecules on alumina (141). 

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