ENANTIOSELECTIVE HYDROGENATION OF ETHYL PYRUVATE IN FLOW REACTOR OVERPt-CD/Si0(2) CATALYSTS

Abstract

ABSTRACT The continuous enantioselective hydrogenation of ethyl pyruvate (EP) in a continuous flow reactor at 25oC on 1%Pt-CD/SiO 2 catalysts has been studied. The catalytic study included the analysis of variables such as: particle size, feed flow, H 2 pressure and the addition of chiral modifier to the reactor feed. The catalysts were prepared using impregnation of Pt colloids which are stabilized with different quantities of cinchonidine (CD) on SiO 2 . This process gives chiral properties to the catalyst and allows changing the particle size for the reaction of interest. The catalysts were characterized by adsorption/desorption isotherms of N 2 a 77 K, TEM, XPS and the analysis of products by GC-MS. The monitoring of the reaction indicates a significant increases in the conversion when decreasing the contact time and a maximum in the enantiomeric excess (ee) of 63 % to the (R)-ethyl lactate which is obtained after using 200mg of 1%Pt/SiO 2 catalyst (1.6nm) at 10 bar of H 2 and a flow of 0.3 mL/min of a mixture EP (0.01M) and CD (0.034M) in cyclohexane.Keywords: Continuous hydrogenation, Nanoparticles, Platinum, Ethyl Pyruvate, Cinchonidine. e-mail: doruiz@udec.cl, preyes@udec.cl