Polyisobutylene production process with improved efficiencies and/or for forming products having improved characteristics and polyisobutylene products produced thereby

A process for production of polyisobutylene comprising:

• subjecting a reaction admixture comprising isobutylene, a diluent for said isobutylene and a catalyst composition to reaction conditions suitable for causing at least a portion of said isobutylene to undergo polymerization to form a polyisobutylene product including polyisobutylene molecules, at least a fraction of said polyisobutylene molecules having alpha position double bonds, said polyisobutylene product having a number average molecular weight and a polydispersity index, said polyisobutylene product having at least one parameter that is variable as a function of the concentration of said diluent in said admixture, said at least one parameter comprising (a) the relative size of said fraction, (b) the number average molecular weight of said product, (c) the polydispersity index of said product or (d) the relative size of said portion;
• choosing a diluent concentration corresponding to a pre-selected value of at least one parameter;
• and
• maintaining the admixture at said chosen diluent concentration to thereby hold said parameter at said pre-selected value,
• wherein diluent comprising a C3-C16 1-alkene and optionally a C3-C16 alkane is provided to a reactor independently of fresh isobutylene monomer.