Process for recovering and reusing depolymerization catalyst
The present disclosure relates to the recovery of an alkoxide catalyst used in a process depolymerizing a polyester to form a diacid or diester and a diol. The present disclosure also relates to the recovery of an alkoxide catalyst used in a process depolymerizing polyethylene terephthalate to form dimethyl terephthalate and mono ethylene glycol.
1. A process comprising:
(i) contacting an alkoxide containing mother liquor with an adsorbent, thereby adsorbing the alkoxide in the adsorbent; and
(ii) washing the adsorbent with a wash solvent comprising methanol, thereby eliminating at least a portion of ester salts, pigments, or dyes adsorbed in the adsorbent during the contacting the alkoxide containing mother liquor with the adsorbent from the adsorbent.
2. The process of claim 1 , wherein the alkoxide containing mother liquor is obtained from a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
3. The process of claim 1 , wherein the alkoxide containing mother liquor further comprises a diol that is mono ethylene glycol (MEG).
4. The process of claim 1 , wherein the washing the adsorbent is performed 1 to 20 times or until at least about 30% of the alkoxide is adsorbed.
5. The process of claim 1 , wherein the adsorbent comprises silica gel, a silicate derivative, Al 2 O 3 , polymeric alumina, zeolites, activated carbon, polysulfones, polysulfates, polycarboxylates, or any combinations thereof.
6. The process of claim 5 , wherein the adsorbent comprises basic alumina, neutral alumina, or acidic alumina.
7. The process of claim 1 , wherein the washing the adsorbent is performed in counter current flow.
8. The process of claim 1 , wherein the alkoxide comprises sodium methoxide or sodium glycoxide.
9. A process comprising:
(i) contacting an alkoxide containing mother liquor with an adsorbent, thereby adsorbing the alkoxide in the adsorbent; and
(ii) washing the adsorbent with a desorption solvent comprising methanol to obtain a mixture comprising the alkoxide and the desorption solvent.
10. The process of claim 9 , wherein the washing the adsorbent with the desorption solvent is performed 1 to 20 times or until at least about 30% of the alkoxide is desorbed from the adsorbent.
11. The process of claim 9 , wherein the alkoxide in the desorption solvent is re-used in a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
12. The process of claim 9 , wherein the alkoxide comprises sodium methoxide or sodium glycoxide.
13. The process of claim 9 , wherein the alkoxide containing mother liquor is obtained from a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
14. The process of claim 9 , wherein the alkoxide in the mixture is re-used in a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
15. A process comprising:
(i) contacting an alkoxide containing mother liquor with an adsorbent, thereby adsorbing the alkoxide in the adsorbent;
(ii) washing the adsorbent with a desorption solvent to obtain a mixture comprising the alkoxide and the desorption solvent; and
(iii) washing the adsorbent to regenerate the adsorbent.
16. The process of claim 15 , wherein the alkoxide comprises sodium methoxide or sodium glycoxide.
17. The process of claim 15 , wherein the alkoxide containing mother liquor is obtained from a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
18. The process of claim 15 , wherein the alkoxide in the mixture is re-used in a process of depolymerizing polyethylene terephthalate (PET) to form a terephthalate and/or an isophthalate and mono ethylene glycol (MEG).
19. The process of claim 15 , wherein (iii) comprises washing the adsorbent with an acid.
20. The process of claim 19 , wherein the washing the adsorbent with the acid is performed 1 to 20 times.
21. The process of claim 19 , wherein the acid is acetic acid or formic acid.