Synthesis, Characterization and Hydroisomerization Performance of SAPO-11 Molecular Sieves with Caverns by Polymer Spheres

Abstract

Silicoaluminophosphates SAPO-11 molecular sieves with caverns were synthesized using polystyrene (PS) micro-spheres as template. The morphologies of the cavitary SAPO-11 molecular sieves exhibit spherical particles ranging 7-10 lm aggregated from cubic plate microcrystallites which just like the SAPO-11 molecular sieves synthesized with the conventional method, but some caverns of 500-1,200 nm pore size in diameter can be observed on the former material. The strength and distribution of the acid sites of the cavitary SAPO-11 are similar to that of the conventional SAPO-11, but the acid density is slightly low owing to the decreased crystallinity of the cavitary SAPO-11. The micropores size and mesopores size of the conventional SAPO-11 are centered at about 0.45 and 3.8 nm, respectively, while the cavitary SAPO-11 has, in addition to the micropores and mesopores, large mesopores ranging 5-30 nm and macropores ranging from about 100 to 1,200 nm, which were derived from the PS sphere template. Hydroisomerization of n-hexadecane was performed to investigate the catalytic performance of the cavitary SAPO-11. The result showed that, in comparison with the conventional SAPO-11, the cavitary SAPO-11 has high activity based on per active site and high selectivity, owing to the fast diffusion of the reactant and isomer products inside the catalyst.

Synthesis of mesoporous Pt@KIT−6/SAPO−11 VIA in situ encapsulation to catalyze the decarboxylation of oleic acid to C8–C17 alkanes

“…The GC heating program was as follows: an initial column temperature of 100 °C was held for 3 min, followed by an increase to 300 °C at 15 °C/min and another hold for 3 min. The conversion of oleic acid and the yield of C8 − C17 alkanes were calculated using Eqns (1) and ( 2 33,34 These data were all consistent with the standard SAPO−11 pattern (pd# 47-0614). In addition, all catalysts showed characteristic Pt peaks at 2⊔ = 39.8°, 46.2°, and 67.4°, corresponding to the Pt(111), Pt(200), and Pt(220) crystal planes, respectively.…”

Effect of Keggin-type heteropolyacids on the hydrocracking of Jatropha oil

“…14,[31][32][33]43 Through the comparison of different Ni-HPA/nHA catalysts, it was obvious that the Ni-HSiW/nHA catalyst produced more isoalkanes, achieving the highest iso/n ratio (1.78) and lowest pour point (À32 C). The iso/n ratio order was the same as the acidity of these catalysts at 360 C. Based on the 1 H NMR spectra and the results reported by Zhang et al, 44 the increased acidity of the catalyst leads to more formation of carbenium ion intermediates, enhancing both the isomerization and cracking, eventually producing more iso-alkanes and gasoline range alkanes. The proles for the product oil distribution and iso/n ratio were in agreement with it.…”

Hydroisomerization of long-chain paraffins: Mechanism and catalysts. Part I

“…The procedure for the synthesis of the SAPO 11 zeolite suggested in [80] uses polystyrene micro spheres as a hard template. The laboratory SH sample synthesized by this procedure contained 5-30 nm mesopores and 100-1200 nm macropores.…”

“…The catalysts based on hierarchical zeolites were characterized [80,81] as having higher selectivity with respect to highly branched isomers, in particular, to dimethyl substituted isomers, compared with zeolite catalysts containing no mesopores ( Table 6, Fig. 24).…”