Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-I-7THE NEW METHOD FOR KINETIC SCREENING OF CATALYSTSFOR SELECTIVE HYDRATION OF ETHYLENE OXIDER.A. Kozlovskiy, N.V. Deriabina, M.G. Makarov, I.A. Kozlovskiy,J.P. Suchkov, V.F. ShvetsD.I. Mendeleev University of Chemical Technology of Russia,Chair of Petrochemical Synthesis, 9 Miusskaya Square, Moscow, 125047, Russia,tel/fax: +7(499)978-95-54, e-mail: kra@muctr.edu.ruIntroductionEthylene glycol (EG) is one of the major large-scale products of industrial organicsynthesis, with the world annual production of about 14 million t/y. EG is currently producedby noncatalytic (thermal) hydration of ethylene oxide (EO) which proceeds on a serial-toparallelroute with the formation of homologues of glycol:CH2O 2 H 4 O CHOCH2CH2OH 2 H 4 O CHO(CH 2 CH 2 O) 2 H 2 H 4 Ok0 k 1 k 2where k 0 , k 1 , k 2 - rate constants.All of the largest ethylene glycol producers, such as Shell, Dow, BASF and Mitsubishi,conduct their studies on elaboration of high selective catalysts of ethylene oxide hydration 1 . Itis known that typical examples of such catalysts are some anions of salts of weak acids andmetallate-anions 1 . Unfortunately till now there is no formulated criteria for choice of suchcatalysts.In present report we propose the new method for kinetic screening of catalysts forselective hydration of ethylene oxide.Theoretical backgroundGenerally hydration of EO (I) proceeds by four routs: noncatalytic, base-catalytic (byOH – ), acid-catalytic (by H + ) and nucleophyl-catalytic (by anions A – ). The selectivity of eachrout is characterized by distribution factor b i which is equal to ratio of k 1 /k 0 (reaction I).Evidently the lower b i is,the higher selectivity of EG formation is. The distribution factors ofnoncatalytic, base-catalytic and acid-catalytic reactions are known to be equal to 2.6, 14.8 and1.6 correspondingly 2 . Hence the overall selectivity is determined by the value of distributionfactor of nucleophyl-catalyzed reaction and ratio of reaction rate of that route to the rates ofall others. Effective rate constant of reaction (I) concerning EO consumption is described byfollowing equation:k eff = k nc + k 1 C A + k a [H 3 O + ] + k b [HO – ] , s –1 (1)etc.(I)223