Lipase-immobilized magnetic chitosan nanoparticles for kinetic resolution of (R,S)-ibuprofen
摘要:
Chitosan (CS)-poly[N-benzyl-2-(methacryloxy)-N,N-dimethylethanaminium bromide] coated magnetic nanoparticles were prepared by co-precipitation method via epichlorohydrin CS cross-linking reaction and were used in the kinetic resolution of (R,S)-ibuprofen by enantioselective esterification. Enzyme immobilized onto the surface of the new magnetic supports with the use of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysulfo-succinimide sodium salt (sulfo-NHS) procedure demonstrated high catalytic activity that enabled us to obtain (S)-methyl ester of ibuprofen with high enantioselectivity (E = 50.6). The chiral compounds that resulted from the application of magnetic nanoparticles were analyzed with the use of chiral stationary phases. It should be emphasized that the main advantage of the support is the possibility to magnetically recovery and effective separation (even up to 5 s) from the reaction mixture with the use of magnet. The properties of magnetic particles allow for better optimization and may reduce the total costs of the esterification reaction of ibuprofen. Moreover, the application of lipase-immobilized magnetic supports enables to maintain high enantioselective activity after repeated use. (c) 2013 Elsevier B.V. All rights reserved.
METHOD FOR PRODUCING ORGANIC TELLURIUM COMPOUND AND METHOD FOR PRODUCING VINYL POLYMER
申请人:OTSUKA CHEMICAL CO., LTD
公开号:US20220009885A1
公开(公告)日:2022-01-13
Provided is a method for producing an organic tellurium compound that enables the production of an organic tellurium compound in high yield using metallic tellurium as a source material and produces less amount of side products. A method for producing an organic tellurium compound includes the steps of: (A) reacting metallic tellurium with a compound represented by a general formula (1) below; and (B) reacting a compound obtained by the step (A) with an organic halogen compound, the metallic tellurium having a copper content of less than 100 ppm,
M(R
1
)m Formula (1)
where R
1
represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, M represents an alkali metal or an alkaline earth metal, m represents 1 when M is an alkali metal, and m represents 2 when M is an alkaline earth metal.
An object of the present invention is to provide a novel copolymer useful as a dispersing agent for a pigment or the like. The novel copolymer contains: a block chain (A) comprising at least one repeating unit selected from the group consisting of a repeating unit having a tertiary amino group and a repeating unit having a quaternary ammonium salt group; and a block chain (B) comprising a repeating unit having an acidic group and a repeating unit represented by the following formula (I) (wherein R1 represents a hydrogen atom or a C1-C3 alkyl group; and R2 represents an aliphatic hydrocarbon group or an alicyclic hydrocarbon group), wherein the repeating unit represented by formula (I) has a copolymerization ratio of 90 mass% or more in the block chain (B).
Ion triggerable, cationic polymers, a method of making same and items using same
申请人:——
公开号:US20040055704A1
公开(公告)日:2004-03-25
The present invention is directed to ion triggerable, water-dispersible cationic polymers. The present invention is also directed to a method of making ion triggerable, water-dispersible cationic polymers and their applicability as binder compositions. The present invention is further directed to fiber-containing fabrics and webs comprising ion triggerable, water-dispersible binder compositions and their applicability in water-dispersible personal care products, such as wet wipes.
Process for preparing an aqueous dispersion of a quaternary ammonium salt containing vinyl copolymer
申请人:Calhoun C. Glenn
公开号:US20050209396A1
公开(公告)日:2005-09-22
A method of making an ion triggerable cationic polymer by solution copolymerizing one or more vinyl-functional cationic monomers, one or more water insoluble or hydrophobic vinyl monomers with alkyl side chains up to 4 carbons long, and, optionally, a minor amount of one or more vinyl monomers with linear or branched alkyl groups longer than 4 carbons, alkyl hydroxy, polyoxyalkylene, or other functional groups. The solution polymerization is accomplished by free radical polymerization in a mixture of acetone and water.