Cyclic ether polymerization using silicon compound accelerators
AssigneeE. I. Du Pont de Nemours and Company
InventorNeville E. Drysdale
Life of this patent
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Abstract
When selected silicon compounds are added to cationic polymerizations of cyclic ethers such as oxiranes and tetrahydrofurans, the rate of polymerization is often increased, and novel polyethers are produced. The polyether products are useful as monomers and macromonomers, particularly after hydrolysis of silicon containing end groups.
Claims12
In a process for cationic polymerization of cyclic ethers comprising contacting a cationic catalyst with one or more tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes, to produce a polyether;
- the improvement consisting essentially of contacting an accelerator with the polymerization mass wherein said accelerator comprises silicon bound to a group whose conjugate acid has a pKa in water of less than about 16, and provided that:
- said accelerator does not significantly react with said cationic catalyst for said cationic polymerization in the absence of said tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes;
- said accelerator does not itself cause polymerization of said tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes to produce a polyether;
- and
- wherein said process is carried out at about -80.degree. C. to about 130.degree. C., and water is not present.
A process for the production of polyethers, consisting essentially of, contacting at a temperature of about -80.degree. C. to about 130.degree. C., a Bronsted or Lewis acid with one or more tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes, and an accelerator, wherein said accelerator is a silicon compound having a group bound directly to a silicon atom whose conjugate acid has a pKa of less than about 16 in water, and provided that:
- said accelerator does not significantly react with said Bronsted or Lewis acid in the absence of said tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes;
- said accelerator does not itself cause polymerization of said tetrahydrofurans, oxepanes, 1,3-dioxolanes or 1,3,5-trioxanes to produce a polyether;
- and
- water is not present.
Dependencies are inferred from the claim text.