Recovery of terephthalate diesters from glycol residues
AssigneeEastman Kodak Company
InventorAndrius Algimantas Naujokas
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Abstract
There is described a process for improving the yield of difunctional ester in a process of recovering monomer components from condensation-type polyester resins such as polyethylene terephthalate by converting terephthalyl monomers and oligomers present in ethylene glycol still bottoms to terephthalate diester, such as dimethyl terephthalate. This is accomplished by treating the terephthalyl monomers and oligomers with a mixture of an alcohol and an alkali metal hydroxide at a temperature up to the boiling point of the alcohol.
Claims7
A process for recovering terephthalate diester from a first mixture comprising terephthalyl monomers, terephthalyl oligomers and ethylene glycol oligomers comprising the steps of:
- a) contacting the first mixture with a second mixture comprising an alcohol and an alkali metal hydroxide at a temperature in the range of from 0.degree. C. to the boiling point of the alcohol and a pressure in the range of 0 psig to 100 psig,
- b) allowing the mixture formed in step a) to react for a period of from 0.5 to 30 minutes, and
- c) separating the terephalate diester formed in step b) from the liquid glycol residue.
Dependencies are inferred from the claim text.