Method for making alkyl-.alpha.-cyanoacrylate from depolymerization of poly(alkyl-.alpha.-cyanoacrylate)
US5436363A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1994 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Oct 3, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C253/30
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A depolymerization and purification process, by which a poly(alkyl-.alpha.-cyanoacrylate) feed is depolymerized into high-purity cyanoacrylate monomers without the use of a high-boiling heat transfer medium such as tricresyl phosphate. The poly(alkyl-.alpha.-cyanoacrylate) feed, which contains one or more polymerization inhibitors such as hydroquinone and phosphorus pentoxide, is first introduced into a thin-film evaporator for a depolymerization reaction. The temperature of the film evaporator is maintained at about 200.degree..about.260.degree. C., and operated under a vacuum of 1.about.20 mm Hg. The produced gas stream from the depolymerization reactor is subject to a two-stage heat transfer process for condensation and purification. The first stage involves a very-high temperature condenser (about 150.degree. C.). The residue collected in the first stage condenser contains primarily dimers of .alpha.-cyanoacrylate. The second stage involves a conventional condenser at room temperature or lower temperature. The gaseous stream leaving the intermediate very-high temperature condenser contains primarily the desired cyanoacrylate monomer, thus it can be conveniently condensed in a c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.