Hydroisomerization and hydrocracking. 2. Product distributions from n-decane and n-dodecane

Abstract

The hydroisomerization and hydrocracking of n-decane and n-dodecane on an ultrastable zeolite Y, containing 0.5 wt % platinum, at T = 130-250 °C and P = 5-100 bar was Investigated. The product distributions are a unique function of the total conversion only and are typical for a carbenium ion mechanism. Primary products are the monobranched isomers of the n-alkane feed. Multibranched feed isomers and cracked products are formed in consecutive reactions. Secondary cracking reactions start at high conversion levels (>90%) only. The energetically favored cleavage of some multibranched feed isomers is more probable than the previously proposed exclusive cracking of monobranched feed isomers.

n-Heptane hydroconversion over nickel-loaded aluminum- and/or boron-containing BEA zeolites prepared by recrystallization of magadiite varieties

“…Ammonium or sodium forms of the zeolite samples were prepared by repeated ion exchange with 0.5 M ammonium or sodium chloride solutions (25 ml/g), pH value of 7.5-8 was adjusted with ammonia and NaOH solution, respectively. Subsequently, nickel ions were incorporated into the Na-and NH 4 -zeolites by ion exchange with 0.08 molar nickel acetate solution at room temperature or 340 K for 5h. Then the samples were washed with water, and dried at about 353 K. The chemical compositions of the prepared samples are listed in Table 1.…”

“…This Dn OH shift of 88 cm -1 was found for all BEA zeolites independently from their framework boron contents. Since Dn OH reflects the deprotonation energy of the OH group [16], it can be concluded that in BEA zeolites bridged hydroxyls associated with Al(OSi) 4 units are, independently of co-existing framework boron, of the same intrinsic acid strength. The intrinsic acid strength was also not affected by incorporation of sodium cations by ion exchange up to exchange levels of 50-60 % (spectra are not shown).…”

“…The integrated intensity of the band at 3610 cm -1 was considered to be proportional to the amount of Brønsted acid sites and related to the corresponding band intensity in the spectrum of NH 4 ). Thus, it can be concluded that in boron containing BEA zeolites residual sodium ions occupy sites associated with tetrahedral aluminum and not those related to framework boron which are predominantly occupied by nickel ions.…”

“…Hydroconversion reactions of alkanes over bifunctional Pt/H-zeolite catalysts have been extensively studied since the 70ties of the last century [1][2][3][4][5][6][7]. The path and mechanism of the involved reactions, the nature and mode of action of the diverse catalytically active sites in the individual catalyst components, the role of the chain length of the paraffinic reactants and reaction conditions, and the significance of the crystal structure of the zeolite applied as acidic component of the catalyst have been studied in detail.…”

Hydrocracking of Fischer‐Tropsch waxes: Kinetic modeling via LHHW approach

“…In particular, Weitkamp and coworkers have investigated product distribution, with an insight into isomers composition. [1][2][3][4] These works are outstanding in the definition of the HDK reaction mechanism, mainly concerning the formation of branched products and CAC bond scission pattern. Later, Froment and coworkers focused on the development of a kinetic model for the HDK reaction of model compounds.…”