Membrane preparation carboxylate form

Polyazetidine prepolymer may be cross-linked in aqueous solution by reaction with amine, thiol, hydroxyl, carboxylic add or other polyazetidine groups. Cross-linking occurs upon water removal, heating or by changing to a basic pH. The immobilised cell/polymer composition may be prepared in the form of membranes, fibres, tubes or beads. 

Cytochrome exists in a soluble form in erythrocytes and in a membrane bound form in microsomes. A soluble derivative of hepatic cyt bs with 93 amino acids can be isolated by treatment of microsomes with pancreatic lipase and this form has essentially the same amino acid sequence as the erythrocyte protein. Further treatment of the soluble form with trypsin cleaves two residues from the N-terminal and seven from the carboxylate-terminal and leaves the heme core with only 84 residues. Rat liver cyt b has been prepared by expression in Eschericha coli (E.coli). The structure of... 

Terpolymerization (2, 3, 4, 6, 8, 33). Membranes containing both perfluorocarboxylic and sulfonic acid groups can be prepared by hydrolyzing a film formed by terpolymerization of TFE and two PVEX monomers containing a carboxylic ester group and sulfonyl fluoride group. 

In a similar approach, nanoporous membranes have also been prepared without the use of a template [75]. These membranes were also built from a mixture of two LCs, an H-bonded dimer and a covalent linker. The membranes were created by photopolymerization to lock the smectic structure into a network followed by an alkaline treatment to create the pores (Fig. 2.17a) [76]. The H-bonds were formed between two benzoic acid monomers and after deprotonating of the acid moieties the H-bonds break and a carboxylate pore interior was created. The smectic nature of the material resulted in straight pores with a 2D geometry and transmission electron microscopy (TEM) (Fig. 2.17e) revealed a periodicity of approximately 3 nm and pores around 1 nm. 

Hydrogen peroxide can react with carboxylic acid to form peracid when lipase enzyme is used as a catalyst instead of inorganic acid. The peracid will epoxidize alkenes, which results in the regeneration of the carboxylic acid (Scheme 7). The best results were obtained in the nonpolar solvents toluene and hexane or when mixtures of alkene and carboxylic acid were used without solvent (55). Lipases were immobilized on cellulose, polysulfone membranes, or polypropylene beads (56). The lipases were used to convert caprylic acid to its peracid. The peracid was used to convert oleic acid to its epoxide. The best yield of epoxy stearic acid (81%) was obtained with the lipase from Candida antartica. Using a commercial preparation of immobilized C. antartica lipase, various unsaturated carboxylic acids were treated with... 

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