from first principles PP-I-1

PP-III-117Pt /Modified Kaolinite in the Isomerization of n-HexaneZakarina N.A., Volkova L.D., Akurpekova A.K.D.V. Sokolsky Institute of Organic Catalysis and Electrochemistry. Almaty, Kazakhstannelly_zakarina@rambler.ruAt present a large number of studies is devoted to the processes of isomerization ofhydrocarbons to improve octane number of gasoline fraction. Application as the matrix ofPt-and Pd-catalysts, new materials - columnar clays based on natural clays is anactualdirection in the synthesis of modern catalysts of isomerization of n-alkanes. Previously weshowed high activity and selectivity of Al-pillared montmorillonite (AlNaHMM) in theisomerization of n-hexane. This work is devoted to the study of the catalytic activity ofPt-catalysts supported on Al-modified kaolinite clay of Ermakov deposit in Kazakhstan (HKE).Isomerization reaction was carried out in a flow reactor at atmospheric pressure of hydrogenin the temperature range 250-400 o C. According to the XRD and EPR study kaolinite is amixture of different mineral fractions. Kaolinite and montmorillonite are clearly fixed.Compared with MM in kaolinite observed high content of SiO 2 , Fe 2 O 3 (6%) and K 2 O. Thecomposition of kaolinites determines a lower acidity of the contacts. The total content of acidcenters(a.c.) of activated kaolinite is no more than 100.5 mkmol NH 3 /g, 45.3% accounted forweak a.c. with T des. up to 200 °C and 29% of middle a.c. with T des. = 200-300 o C. The totalacidity of HMM is 224.5 mkmolNH 3 /g. The quantity of weak a.c. - 27.7%, middle a.c.responsible for the isomerization, -39.9%. Specific surface area of kaolinite -177,3m 2 / g,NaHMM-245,1m 2 /g The number of micropores is 22,8% for NaHMM,and 12,9 % for theHKE. The difference between the acid and textural properties of catalysts is effected in theactivity and the products of the isomerization. The following table shows the data for Pt / Al(5,0)HKE and Pt/Al(5,O)NaHMM-catalysts.Table. Isomerization of n-hexane on Pt-catalystsCatalyst T, o C % S C6,% S C6+,% С 1 -С 5 i-B 2МB 2,2DMB 2MP 3МP 2.4DМP 3,3DМP 2МGYields of reaction products,%Pt/AlHKE 350,47,9 97,7 100 - - - 41,9 2,9 1,3 0,9 0,1 0,1400 33,5 84,8 94,6 2,1 1,4 - 9,8 12,5 0,9 2,8 0,1 0.1Pt/AlHMM 350 39,0 92,6 99,7 - - 0,1 1,5 20,7 13,9 1,3 1.5 -400 46,8 79,7 98,1 0,9 - - 1,9 21,1 14,4 3,0 5,6 -The peculiarity of the synthesized catalyst on the base of kaolinite clay, as is evident from thetable is the formation of significant amounts (41.9%) 2.2-dimethylbutane. The sameconversion of n-hexane over montmorillonite catalyst did not observed. The formation a largeamount of disubstituted isomers is probably due to the mechanism of the reaction. Increased277