with a residence time of 40 minutes raffinate source 34 a 34 whiting consisted of about 14 isobutylene and was dried to lt 5 ppm h 2 o raffinate source 34 b 34 texas city consisted of about 18 isobutylene and was dried to a moisture content of lt 5 ppm h 2 o the mole ratio of butyl t butyl ether to bf 3 in the complex was 1 1 1 table 3______________________________________isobutylene polymerization usingbf3 btbe and c4 raffinateraffinate mol gpc datasource catalyst mn mw di______________________________________a 0 76 902 1534 1 70a 1 01 916 1446 1 77b 0 52 806 1842 2 29b 0 78 569 1044 1 83______________________________________olefin distribution13c nmr vinylidene trisubstituted tetrasubstituted______________________________________84 12 480 17 381 14 580 15 5______________________________________ using the batch polymerization outlined in example xi with bf 3 btbe catalyst the effect on vinylidene content of varying the mole ratio of btbe to bf 3 was studied in five separate runs summarized in table 4 below the feed was 20 isobutylene in isobutane lt 1 ppm h 2 o the reaction temperature was 18 u00b0 c and the residence time was 40 minutes table 4______________________________________effect of varying mole ratioof ether to bf3 uponvinylidene contentmole ratio mol olefin dist sup 13 c nmrbtbe bf3 btbe bf3 vinylidene tri tetra______________________________________ 1 1 0 38 76 15 91 1 1 0 52 83 17 0 1 1 0 38 75 18 80 8 1 0 52 63 30 71 1 1 0 62 83 15 2______________________________________ the batch polymerization of example xi was repeated except that the bf 3 etherate was prepared from isopropyl t butyl ether ptbe the feed was 20 isobutylene in isobutene containing less than 1 ppm.