The polymerisation of olefinic substances by friedel-crafts catalysts

It has already been found in several reactions that Friedel‐Crafts catalysts are only effective when traces of water are present. We have found that this does not apply to the polymerisation reaction of iso‐butene with BF3 and AlCl3 under conditions where high‐molecular weight products are formed. On the other hand, some indications were found pointing to the fact that the reaction proceeds more slowly when working under dry conditions. The phenomena observed are explained in the most satisfactory way by accepting a polarising effect of the positive metal atom on the olefin. Some possible explanations are given for the phenomena found by Polanyi and co‐workers which indicate that presence of moisture can be important in certain cases.