Oxidative dehydrogenation of 4-vinylcyclohexene to styrene in a two section reactor on metal-containing zeolites

Title : Oxidative dehydrogenation of 4-vinylcyclohexene to styrene in a two section reactor on metal-containing zeolites

Abstract:

This abstract presents the results of the oxidative dehydrogenation of 4-vinylcyclohexene in a two-section reactor in the presence of g-Al₂O₃ (1^st section) and Fe-Zr-Gd-La/HNa-ZSM-5 (2^nd section).
For the study, we used Fe-Zr-M-O/HNa- ZSM-5 (M-alkali or rare earth elements) catalytic systems prepared according to the method.
We previously established that in the temperature range of 250-320°C the main reaction products are conjugated dienes formed as a result of the migration of double bonds. The migration of double bonds in the substrate molecule in this temperature range is thermodynamically more favorable which leads to a sharp increase in the content of 3-ethylidenecyclohexene and ethylcyclohexadiene-1,3 isomers (52-57%).
In order to find experimental confirmation of these assumptions about possible reaction routes and obtain comparative results, the experiments on the dehydrogenation of 4-VCH were carried out in the two-section reactor with a section-by-section supply of oxygen. In the first section, 4-VCH was isomerized over g-Al₂O₃ or Ga₂O₃/HNa-ZSM-5 at a temperature of 350-375°C; and in the second section, dehydrogenation of the forming isomerate over Fe-Zr-Gd-La/HNa-ZSM-5 in the temperature range of 400-450°C.
The obtained results are presented in a table and it is seen that at a temperature of 350/420-375°C/450°C and a molar ratio of 4-VCH:CO₂:O₂=1:4-5:0.05-0.1 the yield of ethylbenzene and styrene increases to 69.0-72.0%. The selectivity of the reaction as a result of reducing the degree of destructive oxidation, cracking and other side reactions of 4-VCH increases from 75.0-77.0 to 86.8-87.2%. Thus, the use of the two-section reactor helps to increase the yield of target products in the temperature range of 350-450°C.

Biography:

Dr. Arzu Akif Jalilova studied Chemical Technology at Azerbaijan State Oil Academy and graduated from academy as a technologist. She is a senior scientific researcher at the Laboratory of “Chemistry of alicyclic compounds” of the Institute of Petrochemical Processes of MSE of Azerbaijan Republic. She received her PhD degree on Petrochemistry in 2013 at the same institute. She conducted researches on the process of producing alkyl aromatic hydrocarbons, especially, ethylbenzene and styrene from 4-vinylcyclohexsene by oxidative dehydrogenation, preparation of catalysts in order to carry out the process, studied the impact of several factors on the process and achieved high results. The results were published in prestigious journals such as “Azerbaijan Chemical Journal”, “Petrochemistry”, “Applied Chemistry”, “Processes of Petrochemistry and oil Refining”, “Theoretical and experimental chemistry”. She will be responsible for the development of catalysts and conducting oxidative dehydrogenation.