Catalytic isomerization of 1‐hexene on hy zeolite

The isomerization of 1‐hexene on 70/80 mesh HY zeolite was studied at 200°C. The observed reaction products are formed via a variety of processes including double bond shift, cis–trans isomerization, skeletal rearrangement, cracking, hydrogen transfer, polymerization, cyclization, and coke formation. By applying the time‐on‐stream theory, the products have been classified as primary, secondary, or both, according to their OPE curves on product selectivity plots. 2‐Ethyl‐1‐butene, which is present as an impurity in the feed, is found to react about 30 times faster than 1‐hexene. Both 2‐hexenes and 3 hexenes are formed primarily from 1‐hexene, while 3 methyl 2 pentenes and 3‐methyl‐1‐pentene formed from 2‐ethyl‐1‐butene. The ratio of the initial rate of deprotonation to that of hydrogen shift in these reactions is ∼15 and ∼100, respectively. All products of skeletal rearrangement are observed to be secondary. Cracking products are produced mainly from precoke, which is also the source of hydrogen in the formation of paraffins. A detailed reaction network along with its associated mechanisms are presented and discussed.