Elsevier

Journal of Catalysis

Volume 208, Issue 2, 10 June 2002, Pages 448-455
Journal of Catalysis

Regular Article
Friedel–Crafts Acylation Catalysed by Heteropoly Acids

https://doi.org/10.1006/jcat.2002.3592Get rights and content

Abstract

The Friedel–Crafts acylation of anisole (AN) with acetic anhydride (AA) in liquid phase catalysed by bulk and silica-supported heteropoly acids (HPA), mainly H3PW12O40 (PW), has been studied. The PW exhibit very high activity, yielding up to 98% para and 2–4% ortho isomer of methoxyacetophenone (MOAP) at 90–110°C and an AN/AA molar ratio of 10–20. Catalyst pretreatment is essential; the activity passes a maximum at a pretreatment temperature of 150°C. The acylation of anisole appears to be heterogeneously catalysed; no contribution of homogeneous catalysis by HPA was observed. PW is almost a factor of 100 more active than the zeolite H-beta, which is in agreement with the higher acid strength of HPA. The PW catalyst is reusable, although gradual decline of activity was observed due to the coking of the catalyst. The acylation is inhibited by product because of adsorption of MOAP on the catalyst surface. The ratio of adsorption coefficients of MOAP and anisole has been found to be 37 at 90°C. Anisole acylation is first order in acetic anhydride, the order in catalyst is 0.66, and the apparent activation energy is 41 kJ/mol in the temperature range of 70–110°C. In contrast to anisole, the acylation of toluene with HPA is far less efficient than that with H-beta. Evidence is provided that the activity of HPA in toluene acylation is inhibited by preferential adsorption of acetic anhydride on the catalyst.

References (22)

  • A. Corma et al.

    J. Appl. Catal.

    (1989)
  • M. Spagnol et al.

    Ind. Chem. Lib.

    (1996)
  • D. Rohan et al.

    J. Catal.

    (1998)
  • E.G. Derouane et al.

    J. Catal.

    (1999)
  • E.G. Derouane et al.

    J. Catal.

    (2000)
  • T. Okuhara et al.

    Adv. Catal.

    (1996)
  • I.V. Kozhevnikov et al.

    J. Mol. Catal. A

    (1996)
  • Y. Izumi et al.

    Microporous Mater.

    (1995)
  • I.V. Kozhevnikov et al.

    Appl. Catal. A

    (2001)
  • H. Zollinger

    Adv. Phys. Org. Chem.

    (1964)
There are more references available in the full text version of this article.

Cited by (165)

  • Synthesis of energy rich fuel additive from biomass derived levulinic acid and furfuryl alcohol using novel tin-exchanged heteropoly acid supported on titania nanotubes as catalyst

    2023, Fuel
    Citation Excerpt :

    The existing reports show that the acid-functionalized catalysts play a vital role in synthesizing levulinate ester products, including zeolites, cation exchange resins, silica-based acid catalysts, heteropoly acids (HPAs), sulfated zirconia, acids supported on MOF, ionic liquids, and metal salts supported on porous materials, etc. [16]. HPA catalysts show better efficacy than traditional acid catalysts such as mixed oxides and zeolites [22]. Amongst all HPAs, dodecatungstophosphoric acid (TPA) possesses higher Bronsted acidity because of the Keggin-type structural stability.

  • A state-of-the-art review on waste plastics-derived aviation fuel: Unveiling the heterogeneous catalytic systems and techno-economy feasibility of catalytic pyrolysis

    2022, Energy Conversion and Management
    Citation Excerpt :

    It was discovered that styrene linear dimers triggered by Bronsted acid sites decompose into styrene, ethylbenzene, toluene, and methyl styrene. Kaur et al., [244] did pyrolysis by Friedel–Crafts acylation from heteropoly acids, which have high Bronsted acidity. In polystyrene pyrolysis, the acidic qualities promote significant breaking, which results in an increase in liquid yield.

View all citing articles on Scopus
1

To whom correspondence should be addressed. Fax: +44-151-794-3589. E-mail: [email protected].

View full text