Effect of fatty acid chain length on initial reaction rates and regioselectivity of lipase-catalysed esterification of disaccharides
作者:Ninfa R Pedersen、Reinhard Wimmer、Jeppe Emmersen、Peter Degn、Lars H Pedersen
DOI:10.1016/s0008-6215(02)00112-x
日期:2002.7
t-BuOH and pyridine (v/v) the effect of fatty acid chainlength (C-4-C-12) on C. antarctica lipase B (Novozym 435, EC 3.1.1.3) catalysed esterification was studied. alpha and beta maltose 6'-O-acyl esters in an anomeric molar ratio of 1.0:1.1 were synthesised independently of the chainlength, but the initial specific reaction rate increased with decreasing chainlength of the acyl donor. The product
The invention relates to a method for manufacturing a heat-resistant mold wherein heat-resistant investment material is inserted in a wax model manufactured in a conventional manner. The invention further relates to a low-dusting investment material, which low-dusting material is in particular heat-resistant. The investment material is applicable in dentistry, particularly for manufacturing molds.
Crude Proteinase N was used as catalyst for the synthesis of carbohydrate (in particular sucrose) esters by transesterification of activated esters in organic solvents. Polymerisable or amphiphilic sucrose esters (methacrylates and laurates) were obtained regioselectively in good yields. The influence of the reaction parameters (temperature, pH, solvent, chain length, solid support) on the reaction rate, yield and selectivity was studied. (C) 2001 Elsevier Science Ltd. All rights reserved.
Proteinase N-catalysed transesterifications in DMSO–water and DMF–water: preparation of sucrose monomethacrylate
The selective acylation of sucrose was catalysed by proteinase N (from Bacillus subtilis) in DMF suspensions, providing 1'-monoesters, and notably, methacryloyl esters. Presence of water up to 7% (vol.) led to faster reactions. Alternatively, a slurry of the enzyme with a minimum volume of DMSO could also be used, despite its ability to denature enzymes. (C) 2000 Elsevier Science Ltd. All rights reserved.
NON-DUSTING AND FAST-WETTING IMPRESSION MATERIAL AND METHOD OF PREPARING SAME