Haag-Dessau Catalysts for Ring Opening of Cycloalkanes

Abstract

A “cracking” good performance: Cycloalkanes, which are easily accessible from the surplus aromatic products of petrochemistry, can be converted under hydrogen into a steamcracker feed consisting mainly of n‐alkanes. The highest yields are obtained on zeolite H‐ZSM‐5 with tiny amounts of noble metals—a catalyst with a new type of cracking performance.

High Performance Ni Based Catalyst for Toluene Hydrocracking

“…Further support for this hypothesis arises from the production of ethane and methane, which are higher in the case of the WI catalyst than in the case of the SSIE catalyst. Again, this cracking towards the smallest hydrocarbons follows the HaagDessau mechanism, which is favored at this temperature in the presence of an acidic catalyst as the H-ZSM-5 [40][41][42][43]; in our case, this functionality may be provided by the support H-ZSM-5.…”

“…However, due to the geometrical constraints in zeolite ZSM-5, a contribution of type A b-scission is very unlike [33]; indeed, in the present study there were not C 8 hydrocarbons. Principal mechanism for acid-catalyzed ring opening of cycloalkanes, after [43,44] and classification of cationic b-scissions according to the degree of branching of the parent carbenium ions involved after Weitkamp et al [35] (the term ''type E 2 b-scission'' was coined later by Buchanan et al [28]). The minimum number of carbon atoms (n c ) necessary for each type of b-scission is given in parenthesis The production of *50% propane was the same for both WI and SSIE catalysts, which can be rationalized by type C and type B (likely B 2 ) b-scissions.…”

Ring Opening of Aromatics

“…72%. [86]. Interestingly, on H-ZSM-5 catalysts loaded with extremely small amounts of noble metal of the order of 10 or 100 wt.-ppm, which cannot be classified either as purely monofunctional or as truly bifunctional, the yields of C 2+ n-alkanes were unusually high (>78%, see Fig.…”

“…10 wt.%, as opposed to less than 0.1 wt.% for the used H-ZSM-5 and H-ZSM-11 catalysts [84]. This has been interpreted in terms of a change of the rate controlling step, as the hydrogen pressure is increased, in much the same way as Meusinger 20 Conversion of methylcyclohexane on zeolite H-ZSM-5 (n Si /n Al = 20) loaded with different amounts of palladium [86]. For H-ZSM-5, the cracking mechanism ratio (CMR) as defined in Eq.…”

“…Section 14.2.2.3.A surprising effect was found[86] when methylcyclohexane was converted on H-ZSM-5 catalysts that had been loaded with different amounts of palladium(Fig. Section 14.2.2.3.A surprising effect was found[86] when methylcyclohexane was converted on H-ZSM-5 catalysts that had been loaded with different amounts of palladium(Fig.…”