Acetylation of 2-methoxynaphthalene with acetic anhydride over a series ofdealuminated HBEA zeolites

The liquid phase acylation of 2-methoxynaphthalene with acetic anhydride wa s carried out in a batch reactor at 120 degrees C over a series of HBEA zeo lites resulting from dealumination of a commercial sample by treatment with chlorhydric acid or with ammonium hexafluorosilicate. Lewis acid sites whi ch correspond to extraframework aluminium species and to transient-state sp ecies (aluminium atoms which are leaving the framework) were preferentially removed. With all the HBEA samples, acetylation of 2-methoxynaphthalene le ads preferentially to 1-acetyl-2-methoxynaphtalene, this compound undergoin g isomerization into 2-acetyl-6-methoxynaphthalene and 1-acetyl-7-methoxyna phthalene as well as deacylation. A maximum in acetylation and isomerizatio n activities is found for a Si/Al ratio between 20 and 35. The low activity of the commercial sample can be related to limitations in the desorption o f acetylated products from the zeolite micropores caused by the large amoun t of extraframework aluminium species present on this sample. Lewis acid si tes were shown to be completely inactive for acetylation and isomerization reactions.