73523-02-1Relevant articles and documents
METHOD FOR PREPARING ALKYL HYDROXYL ACID ESTER AND USE THEREOF
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Page/Page column 5; 6, (2021/09/17)
Provided is a method for preparing an alkyl hydroxyl acid ester, the product and use thereof. The method has advantages of high yield, not producing waste water, gas, or solid, low cost, and is green and environment friendly.
Preparation method and application of hydroxy acid alkyl ester
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Paragraph 0028-0030, (2020/06/16)
The invention relates to a preparation method of a green solvent hydroxy acid alkyl ester, which comprises the following steps: (1) an alkyl alcohol and a hydroxy acid methyl ester or an ethyl ester are mixed under normal pressure or micro-positive pressure in the presence of a catalyst and reacted at the temperature of 50-200 DEG C, and the molar ratio of alkyl alcohol to the hydroxy acid methylester or ethyl ester is greater than 1; (2) at the temperature of 135-170 DEG C, a product methanol or ethanol is fractionated for the first time, and the top temperature of a fractionating column isthe boiling point temperature of methanol or ethanol; (3) atmospheric pressure or reduced pressure distillation is carried out for the second time to obtain redundant reactants alkyl alcohol and unreacted hydroxy acid methyl ester or ethyl ester, and the distillation temperature is controlled to be the boiling point temperature of the alkyl alcohol and the hydroxy acid methyl ester or ethyl ester;and (4) the remaining product hydroxy acid alkyl ester is collected. The method has the advantages of high yield, no generation of any three wastes, low production cost, greenness and environmental protection.
Lipase-catalyzed oligomerization and hydrolysis of alkyl lactates: Direct evidence in the catalysis mechanism that enantioselection is governed by a deacylation step
Ohara, Hitomi,Onogi, Akihisa,Yamamoto, Masafumi,Kobayashi, Shiro
experimental part, p. 2008 - 2015 (2011/03/22)
Lipase-catalyzed oligomerization of alkyl d-and l-lactate monomers (RDLa and RLLa, respectively) was studied for the first time. It has been found that the oligomerization occurs enantioselectively only for d-lactates to give oligomers up to heptamers of lactic acid (LA) in good to high yields by using primary C1 to C8 alkyl groups and sec-butyl group for d-lactate monomers. No reaction happened for all l-lactates in similar conditions. Lipase-catalyzed hydrolysis of alkyl d-and l-lactates was also examined, revealing that the hydrolysis took place for both d-and l-lactates, although l-lactates proceeded a couple of times slower. The hydrolysis results clearly demonstrate that the lipase catalysis mechanism involves an acyl-enzyme intermediate (EM) formation via the acylation step from both d-and l-lactates as a rate-determining step, and the subsequent deacylation step, a nucleophilic attack of water to the EM, takes place to produce free LA. On the other hand, in the oligomerization of d-lactates, the deacylation step, in which a sec-alcohol group of the monomer or of the propagating chain-end attacks to the EM, is only allowed for the sec-d-alcohol group to give a one-LA-unit-elongated oligomer. l-Lactates form the EM; however, the subsequent deacylation reaction with both the sec-l-and sec-d-alcohol groups does not take place, failing in the oligomerization to occur. These results provide with the first direct evidence in the lipase catalysis that the enantioselection is governed by the deacylation step. In the co-oligomerization between l-and d-lactates, the l-isomer retarded the reaction rate of the d-isomer, which was found due to the function of the former as a competitive inhibitor in the acylation step toward the latter.
