Oligomerization of Ethylene in a Slurry Reactor Using a Nickel/Sulfated Alumina Catalyst

Abstract

During the oligomerization of ethylene over heterogeneous catalysts, the production of R-olefins may be lowered because of an accompanying deactivation of catalyst resulting from strong adsorption of products, by isomerization or by a tendency to copolymerize into branched products. The oligomerization of ethylene was studied using Ni(II)/sulfated alumina catalysts prepared with a nonporous fumed alumina (ALON) support. The influences of methods of catalyst preparation and activation upon oligomerization activity were screened using a gas-solid microreactor. On the basis of the test results obtained in the microreactor, a modified form of the superior catalyst was prepared and its performance was examined in more detail using a well-agitated gas-liquid-solid slurry reactor. This catalyst exhibited very good oligomerization activity with no apparent deactivation in the slurry reactor at temperatures at or below 298 K and at near-atmospheric pressure. Complete conversion of the ethylene with the production of mainly two oligomers, 1-butene and 1-hexene, was attained. After 34 h in the slurry, formation of a significant amount of two branched C 6 isomers was observed.

Catalytic oligomerization of ethylene over Ni-containing dealuminated Y zeolites

“…The microporous character of these materials leads to intracrystalline diffusion limitations which results in a rapid enrichment of polymeric waxes in the micropores. One of the approaches to overcome this problem was the use of catalysts with larger pores, such as Ni/sulfated-alumina [14] and Ni/amorphous silica-alumina [15]. More recently we have reported that Ni-exchanged Al-MCM-41 mesoporous materials revealed very interesting properties for ethylene oligomerization performed in a threephase batch reactor [8].…”

Ni-exchanged AlMCM-41?An efficient bifunctional catalyst for ethylene oligomerization

“…Other usual homogeneous catalysts are AlR 3 (Ziegler type) and Me(OR) 4 -AlR 3 (Ziegler-Natta type) [1]. A significant research effort has also been directed to the development of a heterogeneous process to take advantage of easy separation of catalyst and oligomers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Nickel-loaded zeolites [2][3][4][5][6][7], usually obtained by metal ion exchange showed good catalytic activity in the gas-phase reaction of ethylene.…”

“…One of the approaches to overcome these problems was the use of a catalyst with larger pores and tuneable acidity, under mild oligomerization conditions. It was reported that in a three-phase slurry reactor, at low temperature, the nickel/sulfated-alumina [9,10] and especially Ni-exchanged amorphous silica-alumina (NiSA) [11] catalysts are active and very stable for the ethylene oligomerization. Thus, the rate of ethylene oligomerization (120 • C, 3.5 MPa) obtained with NiSA (1.56 wt% Ni, 425 m 2 /g BET surface area) was 11.5 g/(g cat h).…”

Catalysis in the Upgrading of Fischer–Tropsch Syncrude

“…Among others, OLI investigations have been reported on the use of different Ni salts on various silica and alumina supports, 171 Ni/Al 2 O 3 and its phosphorus-promoted analogues, 172 NiSO 4 /TiO 2 -ZrO 2 173 and Ni/SO 2 À 4 /Al 2 O 3 . 174 Cai et al reported that NiSO 4 /Al 2 O 3 was active for OLI of propene; a propene conversion of 98% with 55-88% dimer selectivity could be obtained at 30 1C, 2.5 MPa and LHSV 2 h À1 . 175 In subsequent work on the dimerisation of ethene over NiSO 4 /Al 2 O 3 , it was reported that the nickel loading and temperature of calcination influenced the catalyst activity.…”