Synthesis of mono and difunctional oligoisobutylenes—IV. Modification of α,ω-dichlorooligoisobutylene by reaction with maleic anhydride. Preliminary study on block polycondensation

Thermal dehydrochlorination of α,ω-dichlorooligoisobutylene leads to the formation of both endo and exo double bonds; endo bonds are mainly those of 4-phenyl-2,4-dimethyl-2-pentene; exo double bonds belong either to “short” end-groups. Reaction of dichlorinated oligomers with maleic anhydride gives a mixture of oligomers with anhydride or substituted propenyl or indanic terminations. Pure α,ω-di(2-methyl-2-propenyl)oligoisobutylene was prepared by basic dehydrochlorination of α,ω-dichlorinated oligomer; only exo double bonds are formed. This α,ω-unsaturated oligomer reacts with maleic anhydride, giving an oligomeric mixture with functionality, with respect to anhydride, of 1.25 but containing endo double bonds and indane rings. When a catalyst is added (dichloromaleic anhydride), two molecules of anhydride can react with the same end of chain. Various polyamides were prepared from the α,ω-dianhydride oligomers.