The isopropylation of naphthalene over USY zeolite with FAU topology. The selectivities of the products

Yoshihiro Sugi*, Stalin Joseph, Kavitha Ramadass, Sathish Clastinrusselraj Indirathankam, Selvarajan Premkumar, Venkata D.B.C. Dasireddy, Jae Hun Yang, Alaa H. Al-Muhtaseb, Qing Liu, Yoshihiro Kubota, Kenichi Komura, Ajayan Vinu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The isopropylation of naphthalene (NP) over USY zeolite (FAU06, SiO2/Al2O3 = 6) gave all eight possible diisopropylnaphthalene (DIPN) isomers: β,β- (2,6- and 2,7-), α,β- (1,3-, 1,6-, and 1,7-), and α,α- (1,4- and 1,5-). The catalyses were operated under kinetic and/or thermodynamic controls depending on the reaction temperatures since the cavities of FAU topology are wide enough to form all DIPN isomers. Enhanced selectivities for β,β-DIPN were observed at the early stages at 200°C, 250°C, and 300°C although the selectivities decreased with the increasing periods, accompanying the increase in α,α- and α,β-DIPN. The enhancement occurred under new types of thermodynamic controls through thermodynamically preferred transition states to β,β-DIPN. Triisopropylnaphthalene (TriIPN) isomers were also formed in the isopropylation. Unstable α,α,β-TriIPN (1,4,6- and 1,3,5-) was predominantly formed at lower temperatures, however, decreased with the increased of stable α,β,β-TriIPN (1,3,6- and 1,3,7-) at higher temperatures. The predominant formation of 1,4,6-TriIPN was also observed in the initial stages in the range of 200°C, 250°C, and 300°C, as reaction period was increased, while the selectivity for the isomer was decreased with concomitant increase in the selectivities for the other isomers. These changes of the selectivities operated under kinetic and/or thermodynamic controls. Large cavities of the zeolite allowed the formation of all TriIPN isomers without steric restriction.

Original languageEnglish
Pages (from-to)606-615
Number of pages10
JournalBulletin of the Chemical Society of Japan
Volume94
Issue number2
DOIs
Publication statusPublished - 2021
Externally publishedYes

Keywords

  • USY j NP j Isopropylation

ASJC Scopus subject areas

  • Chemistry(all)

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