Alkane hydroconversion

Huybrechts, W., Mijoin, J., Jacobs, P.A. et al. (2003) Development of a fixed-bed continuous-flow high-throughput reactor for long-chain n-alkane hydroconversion. Appl. Catal. A Gen., 243, 1. 

Simulating shape selectivity in alkane hydroconversion by zeolites... 

Using configurational-bias Monte Carlo simulations we quantify how molecular sieves shape selectively modify the free energy of formation of adsorbed hydrocarbons. This allows for a basic thermodynamic analysis to explain the differences in alkane hydroconversion between MFI- and MEL-type molecular sieves, and regularities in the alkane yields of TON-type molecular sieves. 

Simulating shape selectivity in alkane hydroconversion by zeolites M Schenk, T.L.M. Maesen andB. Smit... 

To a number of unexpected shape-selectivity phenomena with long alkane hydroconversion the term inverse shape selectivity was coined [62]. In zeolite pore widths of 0.65-0.74 nm, the opposite was encountered, as expected from mere geometric effects, that is, preferential formation of branched over linear hydrocarbons, viz. the formation of high yields of dibranched from n-alkanes over 10-MR zeolites like API (SAPO-5), the phenomenon being confirmed by adsorption experiments [63]. The molecular basis of such effects has been attributed to a purely entropic effect in monodimensional pores at high pressures expelling larger molecules by smaller ones [64]. 

On ZSM-22, modeling of alkane hydroconversion needed to differentiate between pore, pore mouth and external surface adsorption [82]. The issue... 

Recently, Weitkamp and coworkers[75] applied the CLD-modified HZSM-5 zeolite catalyst to the hydroconversion of methylcyclohexane (MCH) to obtain high-quality water vapor cracking feedstock that is, C2 normal alkanes. The modifying agent they used was Si(OC2H5)4 (TEOS), and the solvent was n-heptane. The preparation procedure is similar to that invented by Gao et al., and the reaction results are listed in Table 6.19. 

Grau, J.M., Yori, J.C., Vera, C.R., Lovey, F.C., Condo, A.M., Parera, J.M. (2004). Crystal Phase Dependent Metal-Support Interactions in Pt/S042--Zr02 Catalysts for Hydroconversion of n-Alkanes. Applied Catalysis A General, Vol.265, No.2, 0uly 2004), pp. 141-152, ISSN 0926-860X... 

A review on cage and window effects in mainly hydroconversion of alkanes with zeolites [73] shows that bi- and even trinodal distributions of product carbon numbers can be formed. In the erionite (ERI) cage Cs hydrocarbon fragments are selectively trapped, thus undergoing intense secondary cracking. This effect was confirmed in the ketonization of carboxylic acids [74]. Alternatively, in cases of slow diffusion (and counterdiffusion), viz. in the liquid-phase propylation of benzene in mordenite, the possibihty of having pore-mouth catalysis was advanced [75]. Multinodal product distributions from... 

The hydroconversion of -alkanes over noble metal-loaded zeolites follows a bifunctional mechanism, in which the reactant is dehydrogenated on the metal particles and the formed alkene is isomerized and/or cracked over the acid sites of the zeolite, followed by a subsequent hydrogenation of all unsaturated products on the metallic sites (see reaction Scheme 7). 

A large tetramethylbranched alkane (2,6,10,14-tetramethylpentadecane) was used as a model for investigating the hydrocracking reaction pathways [12]. Hydroconversion of this substrate over Pt/SiO -Al Oj and Pt/USY zeolite catalysts resulted in two parallel reactions methyl... 

---