The catalytic properties of tungstated zirconia in n-heptane isomerization

Abstract

The catalytic properties of zirconia modified with different amounts of tungstate anions in the hydroisomerization of n heptane and its mixtures with benzene or toluene have been studied. It has been found that at a low temperature of 170°C, the yield of isoheptanes reaches 62.8% with a fairly high selectivity of 87.6% on the Pt/WO 4 2-/ZrO 2 catalyst prepared by impregnation to contain 17.6 mol % tungstate anions. Under the same conditions, the yield of isoheptanes on a sulfated Pt/SO 4 2-/ZrO 2 catalyst is as low as 14.0% with a selectivity of 20.3%. The hydroisomerization process effectively occurs on the tungstated catalyst in the presence of benzene or toluene.

ISOMERIZATION OF LIGHT FRACTION OF STRAIGHT-RUN GASOLINE ON Pt-AND Pd-CATALYSTS SUPPORTED ON PILLARED BY Al, AlZr AND Ti MONTMORILLONITE IN Na-AND Ca-FORMS

“…Besides, small amounts of chlorine are found in powder of the catalyst, other results of quantitative elementalanalysis of the catalyst in comparison with the support after palladium introduction practically don't change. Similar results have been received in case of 0,35%Pt/Al (2,5) NaHMM+HM -catalyst. According to the analysis the amount of platinum in this catalyst is 0,27% that is close to the introduced his quantity.…”

“…Textural properties of three studied catalysts are characterized by small decrease in a specific surface of the catalyst when supporting platinum from 172,7 to 169,0 m 2 /g in a case 0,35%Pt/Al (2,5) NaHMM+HM (table 2) and from 190,7 to 182,7m 2 /g for 0,35%Pt/Ti ( 5) NaHMM+HM. The support of these catalysts differs in the considerable maintenance of micropores which quantity grows when supporting platinum.…”

“…In case of the Pd-catalyst supported on pillared by Al and Zr montmorillonite in Caform more essential reduction of a specific surface area and decreaseof quantity of microporesis observed. It is possible to see the growth of the amountof microporesand the decrease of amount of a mesopores when supporting platinum by comparison of curves of distribution of a poresby the sizes in the support and in Pt/Al (2,5) NaHMM+ HM -the catalyst (fig. 1).…”

“…Introduction. The process of an isomerization of paraffin hydrocarbons of oil has acquired high relevance in connection with the transition to use of more effective and ecologically safe fuels [1][2][3][4] in recent years. One of the ecologically safest ways of improvement of anti-detonation properties of straightrun gasolines is the use of process of a catalytic isomerization of n-alkanes with receiving high-octane isomers on effective Pt and Pd-catalysts [5][6][7][8].…”

“…The isomerization of the real light fractions of oil consisting generally of pentanes of C 5 and C 6 hexanes gains the increasing value in connection with toughening of ecological requirements to motor fuels and need of production of alkylgasolines with high octane number [15,16]. Earlier it has been shown that on reduction of stationary isomerization activity in reaction of hydroconversion of n-hexane the developed Pt-and Pd-catalysts on pillared with various oxides montmorillonite it is possible to arrange in following row: Pt/Al (2,5) NaHMM (53.0%)>Pd/Al:Zr(1:1)CaHMM (35,0%)> Pt/Ti (5,0) NaHMM+ HM (34,0 of %)>Pd/Al:Zr (3:1) CaHMM(31,0%)>0,1%Pt/Al (5,0)NaHMM+HM (20,2%). Due to stated, the present article is devoted to a research of properties of the mordenitecontaining Pt-and Pd-catalysts supported on pillared Al, AlZrandTi the activated montmorillonite in an isomerization of easy fraction of straight-run gasoline (b.b.…”