Preparation and Catalytic Evaluation of a Palladium Catalyst Deposited over Two‐Dimensional Zeolite ITQ‐2 Modified with N‐Donor Groups

Two‐dimensional zeolite ITQ‐2 was reacted successively with (3‐chloropropyl)triethoxysilane, 2‐( N , N ‐diethylamino)ethylamine, and ammonia to give a support bearing the ≡Si(CH 2 ) 3 NHCH 2 CH 2 NEt 2 groups at the surface. Subsequent treatment with palladium(II) acetate afforded an immobilized palladium catalyst 3 , which was tested in the Heck coupling of n ‐butyl acrylate with bromobenzene to give n ‐butyl cinnamate ( 4 ). This (pre)catalyst, which acts as a source of active metal species for the reaction occurring in the liquid phase, showed good activity in N , N ‐dimethylformamide and N , N ‐dimethylacetamide at 150 °C. Reaction tests with different bases revealed a pronounced effect of the base additive on the course of the catalyzed process in terms of both the activity (yield of the coupling product) and selectivity [amount of n ‐butyl 3, 3‐diphenylacrylate ( 5 ) resulting from twofold arylation]. Among the hydrated bases, the best yields of 4 were obtained in reactions performed in the presence of CH 3 CO 2 Na · 3H 2 O and Na 3 PO 4 · 12H 2 O, while that with Na 2 CO 3 · 10H 2 O furnished considerably worse results. The use of the respective anhydrous bases not only decreased the yield of 4 but also incited the formation of the unwanted doubly arylated product 5 .