Kinetic characterisation of enzymatic esterification in a solvent system: adsorptive control of water with molecular sieves

Prediction of the Equilibrium Conversion for the Synthesis of Acyl Hexose through Lipase‐Catalyzed Condensation in Water‐Miscible Solvent in the Presence of Molecular Sieve

“…The apparent equilibrium conversions to lauroyl mannose in the solvents are plotted versus the concentration of molecular sieve 3A 1/16 or 4A 1/16 in Figure 4. The conversions were comparable to those previously reported for the synthesis of other esters (1,8,17). The solid and broken curves in the figure were calculated by the method mentioned above from the K C value, the adsorption isotherm of water, and the solubility of mannose in each solvent for molecular sieves 3A 1/16 and 4A 1/16, respectively.…”

“…Because the condensation is thermodynamically controlled, removal of one of the products, usually water, is effective for increasing the conversion. For this purpose, addition of a desiccant such as a molecular sieve to the reaction system has often been adopted (1)(2)(3)(4)(5)(6). However, the criterion for the amount of the desiccant to be added to achieve the desired conversion seems not to be elucidated.…”

Lipase catalyzed acylation of primary alcohols with remotely located stereogenic centres: the resolution of (±)-4,4-dimethyl-3-phenyl-1-pentanol

“…The water activity is probably changed, at least when the temperature is lowered far below 0°C, as the water might freeze, which probably results in a lower water activity than expected. Thus, we added molecular sieves (4 Å ) 35,36 to the reaction at 0°C to obtain a w $ 0 and interestingly, we found that the enantiomeric ratio was lowered from 11.4 (entry 20) to 7.3 (entry 22). It was also obvious that E-value changed with the quantity of molecular sieves added as addition of more molecular sieves gave an even lower E-value (E = 6.1, entry 21).…”

Lipase-catalyzed synthesis of O-lauroyl l-serinamide and O-lauroyl l-threoninamide

“…Because the condensation is thermodynamically controlled, removal of one of the products, usually water, is effective for increasing the conversion. For this purpose, addition of a desiccant such as a molecular sieve to the reaction system has often been adopted (Giacometti, Giacometti, Milin, & Vasić-Rački, 2001;Zhang, Adachi, Watanabe, & Matsuno, 2002). Fig.…”