Catalysis of Organic..

Mantilla, Tzompantzi, Torres and Gómez 618. Gas Phase Trimerization of IsobuteneUsing Green CatalystsAngeles Mantilla 1 , Francisco Tzompantzi 2 , Miguel Torres 1 andRicardo Gómez 21 Universidad Autónoma Metropolitana Azcapotzalco. Av. San Pablo 180, ReynosaTamaulipas, Azcapotzalco, México 02200, D.F.2 Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco No 152,México 09340, D.F.AbstractE-mail: gomr@xanum.uam.mxIn this work, the performance of two green acid catalysts, a TiO 2 synthesized by thesol-gel method and sulfated in situ was compared with a traditional NiY zeolite inthe trimerization of isobutene. The reaction was carried out at mild conditions:atmospheric pressure and 40°C of temperature. The results obtained in the catalyticevaluation showed higher conversion and stability as well as a better selectivity totri-isobutylene for the sulfated titania catalyst with respect to the NiY zeolite.IntroductionThe oligomerization of isobutene is carried out firstly in order to get diisobutylene asa product of the dimerization of isobutene, because of the high octane number of thiscompound, which could be an interesting alternative to the MTBE plantssubstitution. However, this process, like other petrochemical processes, use strongmineral acids HF, H 2 SO 4 and H 3 PO 4 as catalysts, in liquid form or impregnated overa solid support, which are environmentally corrosive and pollutant. It is desirable thesubstitution of these materials with green, environmental friendly catalyst. Severalworks focused in this subject has been published, including thermodynamic studies[1], kinetic studies [2-4], new acid catalyst evaluation and characterization [5-13],process design [14-16] and uses of the product [17-19]. However, in the presentpaper our attention will be devoted to the study of the trimerization of isobutene, dueto the economical interest in the industrial application of triisobutylene, as a sourceof neoacid compounds [20], for the production of dodecylbencene used in thefabrication of biodegradable detergents or for gas-oil additives [21].Several authors suggest the use of the NiY zeolite and Ni/Si-Al as catalysts forthe oligomerization of isobutene [7-9]. The aim of this work is to compare theperformance of two different green acid catalysts: in situ sulfated TiO 2 synthesizedby the sol-gel method [22] with NiY zeolite, in the gas phase trimerization ofisobutene at mild pressure and temperature conditions: atmospheric pressure and40°C, in terms of activity, selectivity and stability.