Production of highly reactive low molecular weight PIB oligomers
In one preferred embodiment, the present invention provides a process for the liquid phase polymerization of isobutylene to manufacture highly reactive PIB oligomers having Mn under 1000, using a catalyst composition comprising a Friedel-Crafts catalyst a complexing agent, a chain transfer agent and a polymerization-retarding agent. A chain transfer agent may be selected from: α-DIB and β-DIB and mixtures thereof. A polymerization-retarding agent may be selected from:
1. A polyisobutylene composition having Mn under 1000 exhibiting a multimodal molecular weight distribution, at least 70% terminal double bonds and a polydispersity under 2.0 prepared using an olefinic chain transfer agent having a molecular weight, Mn, lower than that of said composition, wherein said composition is characterized in that the composition exhibits a low molecular weight relative maximum in its molecular weight distribution corresponding to the presence of said chain transfer agent.
2. The composition according to claim 1 , wherein said chain transfer agent has a molecular weight, Mn, of from 100 to 150 Daltons.
3. The composition according to claim 1 , wherein the polyisobutylene composition has a molecular weight, Mn, of less than 800 Daltons.
4. The composition according to claim 3 , wherein the polyisobutylene composition has a molecular weight, Mn, of from 300 to less than 800 Daltons.
5. The composition according to claim 1 , wherein the polyisobutylene composition has a molecular weight, Mn, of from 300 to 1000 Daltons.
6. The composition of claim 1 , characterized in that the composition exhibits a low molecular weight relative maximum in its molecular weight distribution corresponding to the presence of said chain transfer agent at a content of from 2 weight percent to 20 weight percent.
7. The composition of claim 1 , characterized in that the composition exhibits a low molecular weight relative maximum in its molecular weight distribution corresponding to the presence of said chain transfer agent at a content of from 4 weight percent to 10 weight percent of the composition.
8. The composition of claim 1 , wherein the polydispersity of said composition is no more than about 1.65.
9. The composition of claim 1 , wherein the polydispersity of said composition is from 1.1 to 1.5.
10. A reactive low molecular weight polyisobutylene composition comprising at least 50 mol percent alpha vinylidene terminated polyisobutylene molecules, the composition having a number average molecular weight of no more than 1000 Daltons and is characterized in that the composition exhibits a low molecular weight maximum in its molecular weight distribution corresponding to the presence of an olefinic chain transfer agent.
11. The reactive low molecular weight polyisobutylene composition according to claim 10 , comprising at least 60 mol percent alpha vinylidene terminated polyisobutylene molecules.
12. The reactive low molecular weight polyisobutylene composition according to claim 10 , comprising at least 70 mol percent alpha vinylidene terminated polyisobutylene molecules.
13. The reactive low molecular weight polyisobutylene composition according to claim 10 , comprising from 50 to 99 mol percent alpha vinylidene terminated polyisobutylene molecules.
14. The reactive low molecular weight polyisobutylene composition according to claim 10 , wherein no more than 10 mole % of the PIB molecules of the composition have tetra-substituted double bonds.
15. A reactive low molecular weight polyisobutylene composition comprising at least 50 mol percent alpha vinylidene terminated polyisobutylene molecules, the composition having a number average molecular weight of no more than 1000 Daltons, wherein the composition further includes a polymerization-retarding agent and is characterized in that the composition exhibits a low molecular weight maximum in its molecular weight distribution corresponding to the presence of an olefinic chain transfer agent.
16. The reactive low molecular weight polyisobutylene composition according to claim 15 , wherein the polymerization-retarding agent comprises a phenolic compound.
17. The composition according to claim 15 , wherein said chain transfer agent has a molecular weight, Mn, of from 100 to 150 Daltons.
18. The composition according to claim 15 , wherein the polyisobutylene composition has a molecular weight, Mn, of less than 800 Daltons.
19. The composition according to claim 15 , wherein the polyisobutylene composition has a molecular weight, Mn, of from 300 to less than 800 Daltons.
20. The composition according to claim 15 , wherein the polyisobutylene composition has a molecular weight, Mn, of from 300 to 1000 Daltons.