Processes for recovering dialkyl terephthalates from polyester compositions
AssigneeEastman Chemical Company
InventorsPinguan Zheng, Hannah Grace Harris
Life of this patent
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Abstract
Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to one or more glycols to depolymerization conditions thereby providing one or more depolymerization products. The one or more depolymerization products can be exposed to an alcoholysis process to recover dialkyl terephthalate. Optionally, the one or more glycols can be recycled and re-used in a subsequent dialkyl terephthalate recovery or other process.
Claims20
A process for recovering one or more dialkyl terephthalates from a polyester composition, comprising:
- (a) exposing a first polyester composition to one or more glycols under depolymerization conditions to provide a first mixture, the first mixture comprising a first liquid component and a first solid component, the first liquid component comprising one or more depolymerization products;
- (b) exposing at least a portion of the first liquid component to a first alcohol composition under alcoholysis conditions comprising a temperature of 90° C. or less to provide a second mixture, the second mixture comprising a second liquid component and a second solid component, the second solid component comprising one or more dialkyl terephthalates;
- (c) exposing the second liquid component to distillation conditions to provide one or more recycle glycols, the one or more recycle glycols comprising at least a portion of the one or more glycols;
- and (d) exposing a second polyester composition to at least a portion of the one or more recycle glycols under depolymerization conditions to provide a third mixture, the third mixture comprising a third liquid component and a third solid component, the third liquid component comprising one or more depolymerization products.
The process of 1, wherein, in the step (b) of exposing at least a portion of the first liquid component to the first alcohol composition occurs in the presence of one or more alcoholysis catalysts, wherein, the one or more alcoholysis catalysts is present in an amount of from 0.1 wt. % to 20 wt. %, relative to the weight of the first polyester composition, and wherein the one or more alcoholysis catalysts comprise K2CO3, Na2CO3, Li2CO3, Cs2CO3;
- KOH, LiOH, NaOH;
- NaOMe, Mg(OMe)2, KOMe, KOt-Bu, ethylene glycol monosodium salt, ethylene glycol disodium salt, or a combination thereof.
Dependencies are inferred from the claim text.