Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia

To estimate the optimal100OP-2-10reaction conditions thetemperature effect was studied.80It was obtained, that increase oftemperature leads to increase ofsubstrate conversion as well asoverall reaction rate grow, butselectivity to desired propylene604020Methyl lactate conversionSelectivity to propylene glycolYield of propylene glycolglycol decreases due to increaseof byproducts formation.140 160 180 Temperature, о С200 220Effect of residence time oncomposition of reaction mixtureFig.1. Effect of temperature on the catalytic performance ofCu/SiO 2 catalyst for the hydrogenation of methyl lactate,WHSV=0,18 h -1was studied. It was found, that concentration of substrate is decreased andconcentrations of main products are increased with increasing residence time. It isnoteworthy, that ratio between propylene glycol and propanoic acid in the case oflactic acid hydrogenation and propylene glycol and hydroxyacetone in the case ofalkyl lactate hydrogenolysis was not depending on residence time. The data obtainedallow assuming that formation of propylene glycol and propanoic acid passes throwparallel independent pathways while hydroxyacetone is thermodynamicallyequilibrated with 1,2-propanediol.Conversion, selectivity, yield, %The optimal conditions for propylene glycol synthesis were found. The mostactive catalyst is 45.5 wt. % Cu/SiO 2 at 473 K that provides 98% methyl lactateconversion with 78% selectivity on propylene glycol (Figure 1) while in similarconditions lactic acid conversion and propylene glycol selectivity were 95% and 65%correspondently.References:[1]. Z. Zhang, J.E. Jackson, D.J. Miller, Appl. Catal. A, 2001, v. 219, pp. 89-98.[2]. R.D. Cortright, M. Sanchez-Castillo, J.A. Dumesic, Appl. Catal. B, 2002, v. 39, pp. 353-359.[3]. W.J. Bartley, US Pat. 4628129, 1986.[4]. J.A. Kouba and A. Zletz, US Pat. 4613707, 1986.Acknowledgements:The authors thank Demeshkina M.P. for preparation of catalysts, Zheivot V.I. for workingout the method of quantitative GLC analysis, Utkin V.A. for GLC/MS analysis. The authorswish to express their kind gratitude to Prof. Yurieva T.M. for helpful discussions of the resultsobtained.53