III International Conference

PP-II-110EFFECTS OF THE PROPERTIES OF SO 4 /ZrO 2 SOLID-PHASE CATALYSTS ONTHE PRODUCTS OF R-(+)-LIMONENE DIEPOXIDES TRANSFORMATION ANDREACTION MECHANISMSalomatina O.V., Kuznetsova Т.G. 1 , Korchagina D.V., Moroz E.M. 1 , Paukshtis E.A. 1 ,Volcho K.P., Barkhash V.A., Salakhutdinov N.F.N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, SB RAS, Novosibirsk, Russia1 Boreskov Institute of Catalysis SB RAS, Novosibirsk, RussiaE-mail: ana@nioch.nsc.ruWe have synthesized a number of acidic SO 4 /ZrO 2 catalysts with different content of thesulfate ions. It has been shown for the first time that the qualitative and quantitativecomposition of the reaction mixture of diepoxide limonene transformations changes byvarying the concentration of acid centers on SO 4 /ZrO 2 .A number of acidic SO 4 /ZrO 2 catalysts with different content of the sulfate ions havebeen synthesized. Acidic properties (Lewis and Brønsted nature) of the sulfated zirconiaswere investigated by new method based upon analysis of the characteristic bands of thepyridine in the DRIFT spectra after it’s adsorption from the solution in methylene chloride atroom temperature. This method was elaborated to compare the acidic properties and activityof the catalysts in the similar conditions.The “island” model of the sulfate centers could be proposed on the base of the data. Atsmall addition of sulfate ions (0.9 % SO 4 ) they are able to form new type of Lewis centerswith coordinated unsaturated Zr 4+ cations. At this amount of the sulfate ions they occupy ≈1.5 % of the surface area. Supporting of the 3 % SO 4 could provide for the enhancement ofthe Lewis centers as the sulfate ions occupy only ≈ 3 % of the total area. In fact, the numbersof Lewis centers decrease and centers of the Brønsted nature appear. At higher content of thesulfate ions only Brønsted centers are determined and SSA diminishes noticeablyThe transformations of limonene diepoxides on solid SO 4 /ZrO 2 acids were investigatedby gradually varying the acid properties of the solid catalyst. It has been shown for the firsttime that qualitative and quantitative composition of the reaction mixture of diepoxidestransformations may change by varying the concentration of acid centers in SO 4 /ZrO 2 solidacid. At a 0.9-3 % level of sulfation the dominant compounds were the products of the initialcleavage of the 8,9-epoxy group of limonene diepoxides. With the contents of sulfo groupsincreased to more than 9 %, the key transformations were those that started with cleavage of365