Alkylation of toluene with 1-hexene over macroreticular ion-exchange resins

• The alkylation of toluene and 1-hexene was performed at 373 K over macroreticular resins.
• Double bond isomerization, dimerization and mono-alkylation were the main reactions.
• Neither skeletal isomerization nor cracking reactions were observed.
• With a Ralkene/toluene = 1, selectivity to C12 dimers was 22% and to alkylates 45.5%.
• Products can be used to boost naphtha streams in the refining industry directly.

The macroreticular acidic ion-exchange resins Amberlyst 35, Amberlyst 46 and Purolite CT 275 were investigated as catalysts for the alkylation of toluene with 1-hexene and simultaneous dimerization and isomerization of the olefin at 373 K. After six hours of reaction, 1-hexene conversion was complete. At low toluene concentration double-bound isomerization of 1-hexene was the main reaction. As toluene concentration increased, double-bond isomerization decreased and toluene alkylation and olefin dimerization reactions increased. By using Purolite CT 275 resin and for an almost equimolar toluene to 1-hexene ratio, the selectivity to dimers was 22%, that of mono- and di-alkylated compounds were 42% and 3.5%, respectively, while that of double-bound isomerization was 32.5%. These reactions catalyzed by macroreticular ion-exchange resins of high acid capacity and degree of crosslinking can be useful to boost naphtha streams in the refining industry by reducing volatile compounds and aromatics of low boiling point.

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