Methylcyclohexane and methylcyclohexene cracking over zeolite Y catalysts

Influence of reaction temperature and crystallite size on HBEA zeolite deactivation by coke

“…The mechanism of formation of the first carbenium ions from mcha (step (1)), or alkanes, has been widely discussed [40][41][42]. Furthermore, mcha can undergoes protolytic dehydrogenation and protolytic cracking via pentacoordinated carbonium ion intermediates [34].…”

“…Furthermore, the effect of reaction temperature on the deactivation by coke was mainly reported with very reactive compounds such as olefins [9,21,22] or alkylaromatics [10,[23][24][25] because at low temperature (<250 8C) there is generally no coke formation from paraffins or satured naphthenes which cannot be transformed into more reactive compounds (essentially olefins). However, over strong acid catalysts paraffins [26][27][28] and naphthenes [29][30][31][32][33][34][35] can be cracked and coke produced even at low temperature. That was the reason why in this paper, the transformation of methylcyclohexane was investigated over an acidic HBEA zeolite at 250, 350 and 450 8C.…”

Hydrogenative regeneration of a Pt/La-Y zeolite catalyst deactivated in the isobutane/n-butene alkylation

“…A small band at 450 nm assigned to trienyl carbocations could only be observed within the early stage of the reaction. The formation of such unsaturated carbocations can be rationalized in terms of consecutive hydrogen transfer reactions [33,34]. Donation of a hydride ion from an olefin to a saturated carbocation results in an unsaturated carbocation and an alkane.…”

Formation of aromatics in heavy gasoline and light LCO ends in FCC

“…The formation of aromatic s in the gasoline-LCO border could be evaluated through the conversion of naphthenic compounds [12,13], which are present at significant concentrations in that boiling range and play an important role in some of the reactions taking place in the complex FCC network.…”