The liquid product distribution was mainlyaffected by the natureof active sites in both straight and zigzag channels of the synthesizedzeolites which contribute to the primary and secondary reforming reactions.The primary reaction mainly involves cracking which produces olefinsand paraffins. The secondary reaction which involves cyclization andisomerization can produce mainly naphthenes and aromatics while passingthrough the zigzag path of the zeolite channels.54 Product distribution varied depending on the type of silicasource and synthesis temperature used. Both of these parameters (thatis, silica source and synthesis temperature) contributed to the formationof zeolite pentasil units which in turn affects the localization ofAl and Si atoms within the straight and zigzag channels; this in turnhas a profound effect on the catalytic activity.56 Selectivities toward naphthenes and aromatics were verysmall for samples synthesized using fumed silica, silicic acid, andtetraethyl orthosilicate and at 140 C. In each of these threesamples, the conversion was found to be lower compared to the othersamples which produce more naphthenes and aromatics. This emphasizesthe weaker ability of these catalysts to crack and convert the feedto intermediates which in turn appear for the secondary reaction.The product distributions of SG-140, SG-180, FS-180, SE-180, and TE-180had predominantly naphthenic and aromatic products due to the effectof both straight and zigzag channels. Hence, both primary and secondaryreactions were taking place thus leading to a higher cyclization reaction.
MIRC v7 41-TE crack
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