US3907868A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester waste recovery
Assignee: EIDP Inc
•
Filing: 1974-02-15
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Granted: 1975-09-23
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Expires: 1994-02-15
Abstract
Abstract A continuous process for the recovery of a dimethyl terephthalate from polyethylene terephthalate wastes by: 1. DISSOLVING AND REACTING THE WASTES WITH ETHYLENE GLYCOL, 2. REACTING THE PRODUCT OF STEP (1) WITH AN EXCESS OF A METHANOL, IN THE PRESENCE OF AN ESTER EXCHANGE CATALYST AND AT AN ELEVATED TEMPERATURE AND PRESSURE TO PREPARE DIMETHYL TEREPHTHALATE, 3. DEACTIVATING THE ESTER EXCHANGE CATALYST BEFORE RELEASE OF THE ELEVATED PRESSURE, 4. DISTILLING EXCESS METHANOL, 5. REMOVING SOLIDS, WHICH FLOCCULATE DURING THE ABOVE STEPS, WHILE THE SOLUTION IS STILL HOT, AND 6. RECOVERING THE DIMETHYL TEREPHTHALATE. In a preferred embodiment, dimethyl terephthalate and ethylene glycol are recovered for reuse in the manufacture of polyethylene terephthalate.
Inventors
- 👤 Robert Marion Currie
- 👤 Shubert Gernt Measamer
- 👤 Donald Nelson Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:46
CPC Classifications
C; C07; C07C; C07C67/00; C07C67/03
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
14 words
IN A PROCESS FOR THE RECOVERY OF DIMETHYL TEREPHTHALATE FROM POLYETHYLENE TEREPHTHALATE WASTE BY,
Claim 2
Dependent Claim
14 words
IN A PROCESS FOR THE RECOVERY OF DIMETHYL TEREPHTHALATE FROM POLYETHYLENE TEREPHTHALATE WASTE BY,
Claim 3
Dependent Claim
13 words
DISSOLVING AND REACTING THE WASTE WITH ETHYLENE GYCOL TO PREPARE LIQUID REACTION SOLUTION,
Claim 4
Dependent Claim
13 words
DISSOLVING AND REACTING THE WASTE WITH ETHYLENE GYCOL TO PREPARE LIQUID REACTION SOLUTION,
Claim 5
Dependent Claim
27 words
CONTACTING THE LIQUID REACTION SOLUTION WITH AN EXCESS OF METHANOL AND AN ESTER EXCHANGE CATALYST AT AN ELEVATED TEMPERATURE AND SUPERATMOSPHERIC PRESSURE TO PREPARE DIMETHYL TEREPHTHALATE, AND
Claim 6
Dependent Claim
27 words
CONTACTING THE LIQUID REACTION SOLUTION WITH AN EXCESS OF METHANOL AND AN ESTER EXCHANGE CATALYST AT AN ELEVATED TEMPERATURE AND SUPERATMOSPHERIC PRESSURE TO PREPARE DIMETHYL TEREPHTHALATE, AND
Claim 7
Dependent Claim
27 words
contacting the liquid reaction solution with an excess of methanol and an ester exchange catalyst at an elevated temperature and superatmospheric pressure to prepare dimethyl terephthalate, and
Claim 8
Dependent Claim
27 words
contacting the liquid reaction solution with an excess of methanol and an ester exchange catalyst at an elevated temperature and superatmospheric pressure to prepare dimethyl terephthalate, and
Claim 9
Dependent Claim
50 words
The process of claim 1 wherein the polyethylene terephthalate waste is dissolved and reaCted with ethylene glycol in two stages, the first stage being at atmospheric pressure and a temperature of about 210* to 260*C. and the second stage being under pressure and a temperature of about 220* to 250*C.
Claim 10
Dependent Claim
23 words
The process of claim 1 wherein the weight ratio of methanol to degraded waste in step (2) is at least 3 to 1.
Claim 11
Dependent Claim
109 words
recovering dimethyl terephthalate from the liquid reaction solution, the improvement wherein the process is continuous, in step (2) the weight ratio of methanol to liquid reaction solution is at least about 2 to 1 and the elevated temperature is about 180* to 300*C., and wherein undesired solids are eliminated prior to recovery of the dimethyl terephthalate by: a. introducing a sequestering agent to the hot liquid reaction solution of step (2), before release of the superatmospheric pressure, to deactivate the ester exchange catalyst, b. distilling excess methanol from the hot liquid reaction solution, and c. removing solids from the hot liquid reaction solution at a temperature above about 125*C.
Claim 12
Dependent Claim
109 words
recovering dimethyl terephthalate from the liquid reaction solution, the improvement wherein the process is continuous, in step (2) the weight ratio of methanol to liquid reaction solution is at least about 2 to 1 and the elevated temperature is about 180* to 300*C., and wherein undesired solids are eliminated prior to recovery of the dimethyl terephthalate by: a. introducing a sequestering agent to the hot liquid reaction solution of step (2), before release of the superatmospheric pressure, to deactivate the ester exchange catalyst, b. distilling excess methanol from the hot liquid reaction solution, and c. removing solids from the hot liquid reaction solution at a temperature above about 125*C.
Claim 13
Dependent Claim
109 words
RECOVERING DIMETHYL TRETERPHTHALATE FROM THE LIQUID REACTION SOLUTION, THE IMPROVEMENT WHEREIN THE PROCESS IS CONTINUOUS, IN STEP (2) THE WEIGHT RATIO OF MENTHANOL TO LIQUID REACTION SOLUTION IS AT LEAST ABOUT 2 TO 1 AND THE ELEVATED TEMPERATURE IS ABOUT 180* TO 300*C., AND WHEREIN UNDESIRED SOLIDS ARE ELIMINATED PRIOR TO RECOVERY OF THE DIMETHYL TEREPHTHLATE BY, A. INTRODUCING A SEQUESTERING AGENT TO THE HOT LIQUID REACTION SOLUTION OF STEP, (2), BEFORE RELEASE OF THE SUPERATMOSPHERIC, PRESSURE TO DEACTIVATE THE ESTER EXCHANGE CATALYST, B. DISTILLING EXCESS METHANOL FROM THE HOT LIQUID REACTION SOLUTION, AND C. REMOVING SOLIDS FROM THE HOT LIQUID REACTION SOLUTION AT A TEMPERATURE ABOVE ABOUT 125*C.
Claim 14
Dependent Claim
109 words
RECOVERING DIMETHYL TRETERPHTHALATE FROM THE LIQUID REACTION SOLUTION, THE IMPROVEMENT WHEREIN THE PROCESS IS CONTINUOUS, IN STEP (2) THE WEIGHT RATIO OF MENTHANOL TO LIQUID REACTION SOLUTION IS AT LEAST ABOUT 2 TO 1 AND THE ELEVATED TEMPERATURE IS ABOUT 180* TO 300*C., AND WHEREIN UNDESIRED SOLIDS ARE ELIMINATED PRIOR TO RECOVERY OF THE DIMETHYL TEREPHTHLATE BY, A. INTRODUCING A SEQUESTERING AGENT TO THE HOT LIQUID REACTION SOLUTION OF STEP, (2), BEFORE RELEASE OF THE SUPERATMOSPHERIC, PRESSURE TO DEACTIVATE THE ESTER EXCHANGE CATALYST, B. DISTILLING EXCESS METHANOL FROM THE HOT LIQUID REACTION SOLUTION, AND C. REMOVING SOLIDS FROM THE HOT LIQUID REACTION SOLUTION AT A TEMPERATURE ABOVE ABOUT 125*C.
Claim 15
Dependent Claim
50 words
The process of claim 1 wherein, in step (b), excess methanol is distilled from the hot liquid reaction solution in two stages, the first stage being under superatmospheric pressure and at a temperature higher than the elevated temperature of step (2), and the second stage being at a reduced pressure.
Claim 16
Dependent Claim
24 words
The process of claim 4 wherein methanol evaporated in the first stage is returned to step (2) by passage through a methanol vapor barrier.
Claim 17
Dependent Claim
19 words
The process of claim 4 wherein methanol evaporated in the second stage is condensed and recycled to step (2).
Claim 18
Dependent Claim
22 words
The process of claim 1 wherein the step (c) solids are removed from the hot liquid reaction solution by centrifuging the solution.
Claim 19
Dependent Claim
21 words
The process of claim 1 wherein in step (c) solids are removed from the hot liquid reaction by filtering the solution.
Claim 20
Dependent Claim
20 words
The process of claim 1 wherein in step (c) solids are removed from the hot liquid reaction solution by sedimentation.
Claim 21
Dependent Claim
34 words
The process of claim 1 wherein in step (3) dimethyl terephthalate is recovered from the hot liquid reaction solution by heating the solution to distill first aliphatic components therefrom, and then the dimethyl terephthalate.
Claim 22
Dependent Claim
26 words
The process of claim 10 wherein ethylene glycol is recovered from the aliphatic components and is recycled to be used in the manufacture of polyethylene terephthalate.
Claim 23
Dependent Claim
20 words
The process of claim 10 wherein ethylene glycol is recovered from the aliphatic components and is recycled to step (1).
Claim 24
Dependent Claim
18 words
The process of claim 10 wherein the residue from distilling the dimethyl terephthalate is recycled to step (2).
Claim 25
Dependent Claim
16 words
The process of claim 1 wherein the ethylene glycol is from a polyethylene terephthalate manufacturing process.
Claim 26
Dependent Claim
21 words
The process of claim 1 wherein the ester exchange catalyst is a metal salt of acetic acid or an organic amine.
Claim 27
Dependent Claim
20 words
The process of claim 1 wherein the sequestering agent is a phosphorus compound or an aliphatic or aromatic dicarboxylic acid.
Claim 28
Dependent Claim
13 words
The process of claim 1 wherein the polyethylene terephthalate waste is scrap film.
References Cited (Backward Citations)
US3488298A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |