86728-85-0Relevant articles and documents
Method for continuously preparing (R)-4-halo-3-hydroxy-butyrate by using micro-reaction system
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Paragraph 0071-0093, (2021/02/10)
The invention belongs to the technical field of chemical engineering, and particularly relates to a method for continuously preparing (R)-4-halo-3-hydroxy-butyrate by using a micro-reaction system. Asubstrate solution containing halogenated acetoacetate and a biological catalytic solution are continuously subjected to an enzyme-catalyzed asymmetric reduction reaction in the micro-reaction systemcomposed of a micro-mixer, a micro-channel reactor and a pH regulator so as to obtain the (R)-4-halo-3-hydroxy-butyrate. Compared with the prior art, the method has the advantages that: the reaction time is only a few minutes, the yield of the product (R)-4-halo-3-hydroxy-butyrate is more than 95 percent, the process is continuous, the automation degree is high, the efficiency is high, the technological process is simple and convenient to operate, and the industrial production is easy.
Method for preparing 3 -hydroxy -4 -chlorobutyric acid ethyl ester
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Paragraph 0010-0012, (2021/08/25)
The invention discloses a method for preparing 3 -hydroxy -4 -chlorobutyric acid ethyl ester. The method comprises 4 - chloroacetoacetate as a raw material, methanol as a solvent and sodium borohydride as a reducing agent. The methanol is concentrated to recycle after the reaction is finished. The residue is added with methanol, hydrogen chloride gas is introduced to pH=2 - 3 filtration desalination, and the hydrogen chloride - methanol system is recycled. The residue was distilled under reduced pressure to give ethyl 3 -hydroxy -4 -chlorobutyric acid ethyl ester. The sodium borohydride is low in use amount, no by-product peak occurs, and the yield reaches 83 - 87%. The methanol and hydrogen chloride - methanol two solvent systems are separately recycled, so that the use of a low-boiling-point solvent is avoided. The synthetic process is low in cost, high in yield and environmentally friendly, and can be used for industrial large-scale production.
Synthesis of ethyl (R)-4-chloro-3-hydroxybutyrate by immobilized cells using amino acid-modified magnetic nanoparticles
Dai, Hongqian,Lu, Yuan,Ou, Zhimin,Shi, Hanbing,Sun, Xingyuan,Tang, Lan
, p. 9 - 20 (2020/09/01)
Fe3O4-Arg was selected as the optimal carrier due to its high activity recovery of immobilized cells in the preparation of Fe3O4-Arg-Cells. The optimal immobilization conditions for the preparation of Fe3O4-Arg-Cells were 30 °C, 4 h, pH 7, and 3 g dry yeast. The activity recovery of immobilized cells reached 76.8 percent. For a batch reduction in a shaker in an alternating magnetic field, Fe3O4-Arg-Cells were used as a catalyst to gain ethyl (R)-4-chloro-3-hydroxybutyrate ((R)-CHBE). For further improvement in reduction productivity, a continuous reduction in the magnetic fluidized bed reactor system (MFBRS) was completed. Under their optimal transformation conditions, it took 24 h for Fe3O4-Arg-Cells to complete the conversion of ethyl 4-chloro-3-oxobutanoate (COBE) (0.8553 mol/L) in the shaker and only 8 h for the batch reduction in an alternating magnetic field. Continuous reduction in MFBRS provided new ideas for the efficient production of (R)-CHBE; 1.5882 mol/L (10 mL) of COBE can be completely converted in 6 h. The conversion and enantiomeric excess (e.e.) of (R)-CHBE were 100 percent and above 99.9 percent respectively, in the three reaction systems mentioned above.
