Asymmetric synthesis of (R)-mandelonitrile catalysed by (R)-oxynitrilase from almond in water/organic solvent biphase systems

The asymmetric synthesis of (R)-mandelonitrile from benzaldehyde and hydrog en cyanide using (R)-oxynitrilase from bitter almond in water/organic solve nt biphase systems was studied. The effects of organic solvents, volume rat io of water phase to organic phase, pH value of aqueous phase and reaction temperature on the initial reaction rate, the final conversion and enantiom eric purity of the product were explored. All above mentioned facts had imp ortant effects on the reaction. Diisopropyl ether is found to be the best o rganic solvent for the reaction. The optimum volume ratio of water phase to organic phase, pH and reaction temperature are 1/2, 3.4 and 0 similar to 5 degreesC respectively for the reaction. Under these conditions, both the c onversion rate and enantiomeric excess are as high as 99%.