Catalyst For Transesterification Reaction Research Articles

ChemInform Abstract: Separation, Recovery and Reuse of N‐Heterocyclic Carbene Catalysts in Transesterification Reactions.

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Separation, recovery and reuse of N-heterocyclic carbene catalysts in transesterification reactions

A novel and convenient strategy to separate, recover and reuse N-heterocyclic carbene catalysts in transesterification reactions has been developed.

Products of hydrolysis of C, N-chelated triorganotin(IV) chlorides and use of products as catalysts in transesterification reactions

Triorganotin(IV) chlorides containing one L CN chelating ligand were hydrolyzed with an excess of sodium hydroxide. The composition of the products is strongly dependent on the nature of the organic groups bound to the tin atom. Di( n-butyl)tin, dimethyltin as well as the diphenyl derivative exhibits an equilibrium between hydroxide and stannoxane forms (oxide), whereas alkyltin species react spontaneously and reversibly with carbon dioxide present in the air to form carbonate species. On the other hand, diphenyl derivatives display virtually no reaction with CO 2 towards carbonates, while the di- t-butyl-substituted tin derivative is stable under the same experimental condition and remains as a tin hydroxide. In the case of the dimethyltin derivative, a methyl group migration was observed with displacement of one L CN chelating ligand during the reaction on the air. The coordination geometry of the tin central atom(s) of all studied compounds can be described as trigonal bipyramidal with a dative bonded dimethylamino group occupying one coordination site. The catalytic activity of these compounds in transesterification reactions is generally lower compared to the systems reported in the literature, with the exception of the transesterification of ethyl acetate by cyclohexanol which displays a remarkable activity.

Partial purification ofNigella sativaL. Seed lipase and its application in transesterification reactions

AbstractNigella sativaL. seed lipase isolated from defatted seeds was partially purified and used as catalyst in transesterification reactions. Purification of an ammonium sulfate‐precipitated sample (at 35% saturation,Nigella PL) by DEAE ion‐exchange chromatography increased the specific activity from 13.9 to 156.7 U/mg protein.Nigella PLandNigella CPL(the partially purified enzyme sample obtained by DEAE ion‐exchange chromatography) catalyzed the transesterification of vinyl acetate with octanol, with racemic sulcatol (6‐methyl‐5‐hepten‐2‐ol), and with racemictrans‐sobrerol (trans‐p‐menth‐6‐ene‐2,8‐diol) in different organic solvents. Both activity and enantioselectivity of the enzyme samples used for these biotransformations were affected by the nature of the organic solvent.

Polymer-supported titanates as catalysts for transesterification reactions

Polymer-supported titanates were prepared by covalent bonding of a trialkoxychlorotitane to a preformed macroporous poly(4-hydroxystyrene) resin. The reactivity and stability to recycling of the catalyst obtained were demonstrated in the catalysis of the transesterifications of methyl methacrylate with 2-ethylhexanol and ethyl butyrate with 1-dodecanol. A low leaching of titanium was observed during four successive uses of the resin as a transesterification catalyst.

Synthesis of sterically hindered esters via titanium catalyzed transesterification

Titanium (IV) ethoxide was used as a catalyst in transesterification reactions to synthesize esters of sterically hindered alcohols in good to high yields.

Mild Esterification and Transesterification of Carboxylic Acids Catalyzed by Tetracyanoethylene and Dicyanoketene Dimethyl Acetal

Abstract A π-acid tetracyanoethylene (TCNE) and its derivative dicyanoketene dimethyl acetal (DCKDMA) were found to catalyze esterification of lauric acid with various types of alcohols. This mathod was successfully applied to methyl esterification of a variety of carboxylic acids including aromatic, α,β-unsaturated, α-hydroxy, and N-Cbz and N-Boc-protected α-amino acids without racemization at the range from room temperature to 60 °C. TCNE was also found to operate as a catalyst in transesterification reaction of methyl laurate.