Ethyl acrylate, transesterification with

In liquid phase reactions, the importance of the swelling properties and the related sorption capacities for the catalytic activity of ion exchangers was demonstrated. The rate coefficient of 1-butanol—acetic acid esterification [431] decreased with the degree of crosslinking in the same manner as did the water sorption capacity and the solvation coefficient of 1-butanol. A similar effect was found for the transesterification of ethyl acrylate with 1-butanol [404]. 

This technique, however, was less than satisfactory. The polymeric acid chlorides were very sensitive to hydrolysis and polymer degradation occurred, presumably due to the presence of HCl. This decomposition was reflected by a decrease in viscosity during this reaction sequence. Furthermore, the final polymers exhibited strong, broad hydroxyl stretching bands in their IR spectra. Transesterification was also attempted unsuccessfully. Poly(ethyl acrylate) was reacted with pentachlorophenol in the presence of p-toluene sulfonic acid in benzene. Very little ethanol was Isolated and upon precipitation of the polymer in petroleum ether only oily material remained. 

Various immobilized lipases were tested in the transesterification of 1-O-octyl a-D-glucopyranoside (1) with ethyl acrylate, using the latter compound both as reactant and solvent. By far the best results were obtained with lipase preparations of the Candida antarctica type (see Table 1). Acylation occurred mainly at the 6-0 position, in line with the usual preference of lipases for primary alcohol functions. The resulting 6-O-acryl ester may serve as a starting material for specialty polymers. Acylation at the 2-O-position was the main side-reaction. The selectivity and rate of the C. antarctica lipase catalyzed reaction could be improved substantially by adding zeolite CaA which selectively adsorbs water and ethanol . ... 

Methyl esters are always the preferred substrates, conversions being lower with, for example, ethyl esters. Functional groups such as nitro, methoxy, alkenyl and pyridyl are compatible with the reaction conditions. Diesters can only be effective if bis-transesterification is desired, when an excess of the alcohol (e.g., 3-5 equiv) is necessary. Methyl acrylate tends to polymerize under the reaction conditions, but the use of an excess of the ester (3-5 equiv) and lower temperatures (-10°C) allows efficient isolation of the required ester. 

As with inorganic solid catalysts, the most extensively studied system was acetic acid—ethanol [428,432,434,444—448]. Other alcohols used in kinetic studies were methanol [430,449,450], 2-propanol [438], 1-bu-tanol [429,431,433,451—458], allyl alcohol [459], 1-pentanol [434] and ethyleneglycol [460] besides acetic acid, the reactions of formic [450], propionic [443,461], salicylic [430,449], benzoic [453—457] and oleic acids [430,451—453] and of phthalic anhydride [462] have been reported. Investigation of a greater variety of reactants is reported in only one paper [463] six alcohols (C4, Cs and C8) and five acids (mainly dicarboxylic were studied. Transesterification kinetic studies were performed with ethyl formate [437,439,441], isobutyrate [437,439—441] acetate [402, 435—437,439—442], methoxyacetate [441] and acrylate [403,404,464, 465] the alcohols used were methanol [402,435,437,439—442,450],... 

Conversion of the phthalimide to the amine was confirmed by a peak at (5 3.2 ppm corresponding to the hydrogen adjacent to the amine group. The functionalization reaction was also monitored by MALDI-TOF MS. Characterization of the phthalimide-functionalized polymer confirmed the conversion of the bromide group. Characterization of the amine-functionalized polymer showed the presence of the desired product, but other side products were also observed. Upon hydrolysis of the phtha-limide-functionalized polymer, a transesterification reaction occurs converting the initiator moiety (ethyl-2-bromoisobuty-rate) from an ethyl ester to a t-butyl ester due to reaction with t-butyl alcohol. One drawback of this reaction is that the Gabriel reaction is only effective for primary alkyl halides and would not be useful for methyl methacrylates or methyl acrylates. 

The aUylation of aldehydes with ethyl a-(a-hydroxymethyl)acrylate and ethyl a-(a-hydroxyalkyl)acrylates is successfully preformed under the conditions shown in Scheme 12. The primary product, a-methylene-y-stannyloxycarboxylate, spontaneously undergoes an intramolecular transesterification to provide a-methylene-y-butyrolactone in moderate yield. The high yn-selectivity may be rationalized on the basis of an anti-periplanar transition state. 

Sucrose was actylated at 0-1 preferentially by subtilisin-catatysed transesterification from the trifluoro- or trichloro- ethyl esters of acetic, propionic, octanoic, benzoic, and acrylic acid in DMF. Subsequent hydrolysis of the yoosidic bond with a-glucosidase gave D-fructose l-esters. ... 

Deep eutectic solvents based on choline acetate (ChOAc), which have lower viscosities as compare to the ChCl/Urea eutectic mixture, have been also used as reaction media in several biocatalyzed transesterification reactions. In this sense, Zhao et al. reported the transesterification of ethyl sorbitate with 1-propanol by the lipase Novozym 435 Candida Antarctica lipase B immobilized on acrylic resins), achieving high initial rates (1 pmolmin g ) and selectivity (99%). Furthermore, in a model biodiesel synthesis system, the authors examined the transeterification of the lipid Miglyol oil 812 (a mixture of triglycerides of caprylic acid (C8) and capric acid (CIO)) with methanol, catalyzed by Novozym 435 in ChOAc/Gly (1 1.5 molar ratio). The biocatalytic reaction was very rapid in this eutectic mixture, with 97% conversion achieved after only 3 hours. 

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