The behaviour of several zeolites as catalysts for the title reaction has been investigated by means of a continuous flow microreactor. Runs performed at atmospheric pressure indicated that at 423 K the completely protonic forms of the zeolites catalyze just the isomerization reaction. In the case of Y zeolites, oligomerization occurs only over the partially decationated samples, in the temperature range between 373 and 423 K and W/F between 0.2 and 22 gcath/g1-but, to an extent which depends on the reaction conditions. Most of the catalysts were tested also under pressure (4.05 MPa) at 423 K. The protonic forms of Y and ZSM-5 zeolites seem promising catalysts in terms of both conversion and selectivity to oligomers. The 1-olefins account for 30% of the entire olefinic mixture. The octenes, which account for 70% of the liquid mixture, are mostly formed of dimethylhexenes. Trimers are also formed during the reaction and, in the very particular case of H[B]ZSM-5, tetramers are produced.
Enzymatic synthesis of nucleoside analogues from uridines and vinyl esters in a continuous-flow microreactor