# US 7,608,652 B2 · Catalyst composition for producing polyethylene terephthalate from terephthalic acid and ethylene glycol, and process therefore

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- Number: US 7,608,652 B2
- Document ID: US7608652B2
- Status: Granted
- Kind: B2
- Application number: 10/592,338
- Filed: 2005-02-10
- Published: 2008-02-07
- Granted: 2009-10-27
- Earliest claimed: 2004-03-11
- Assignees: Saudi Basic Industries Corporation
- Inventors: Zahir Bashir; Jamil Siddiqui; Venkatanathan Sampath; Khalid Al-Luhaidan
- Web page: https://patentgrep.com/patent/US7608652B2

## CPC

- C08G 63/866: {Antimony or compounds thereof}
- C08G 63/80: Solid-state polycondensation
- C08G 63/83: Alkali metals, alkaline earth metals, beryllium, magnesium, copper, silver, gold, zinc, cadmium, mercury, manganese, or compounds thereof {(C08G63/823 takes precedence)}
- C08G 63/183: Terephthalic acids
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

The present invention relates to a catalyst composition for producing polyethylene terephthalate from terephthalic acid and ethylene glycol, comprising: (i) an antimony compound, being present such that the elemental antimony is in a range of about 15 ppm to less than 150 ppm; (ii) a zinc compound, being present such that the elemental zinc is in a range of about 40 to about 160 ppm; as well as a process for the preparation thereof.

## Claims

### Claim 1

Process for the production of polyethylene terephthalate from terephthalic acid and ethylene glycol, comprising the steps of:
(a) preparing a catalyst composition consisting of an antimony compound, being present such that the elemental antimony content is in a range of about 100 to about 140 ppm, and a zinc compound, being present such that the elemental zinc content is in a range of about 80 to about 140 ppm, wherein the ppm amounts by weight are based on the theoretical yield of polyethylene terephthalate;
(b) placing the catalyst composition, the terephthalic acid and the ethylene glycol in a vessel; and
(c) reacting the terephthalic acid and the ethylene glycol in an esterification step and a polycondensation step to obtain polyethylene terephthalate.

### Claim 2 (depends on 1)

Process according to claim 1 wherein the antimony compound is selected from the group consisting of antimony triacetate, antimony trioxide, antimony tricarbonate, antimony glycolate or mixtures thereof.

### Claim 3 (depends on 1)

Process according to claim 1 wherein the zinc compound is selected from the group consisting of zinc acetate, zinc oxide, zinc peroxide, zinc suiphide, zinc carbonate, zinc hydroxide, zinc halide, zinc metal or mixtures thereof.

### Claim 4 (depends on 1)

Process according to claim 1 wherein the esterification step is conducted at a temperature of about 230 to about 260° C. and wherein the polycondensation step is conducted at a temperature of about 270 to about 290° C.

### Claim 5 (depends on 1)

Process according to claim 1 wherein the polycondensation step is conducted in the melt phase under high vacuum in a batch process.

### Claim 6 (depends on 1)

Process according to claim 1 wherein the polycondensation step is conducted in the melt phase in a continuous process using a train of reactors in series for esterification and polycondensation.

### Claim 7 (depends on 1)

Process according to claim 1 wherein the polycondensation step is conducted in a split operation using first a melt phase polycondensation step under high vacuum and subsequently a solid state polycondensation step, under vacuum or nitrogen flow.

### Claim 8 (depends on 7)

Process according to claim 7 where the solid state polycondensation step is conducted in a batch or continuous operation.

### Claim 9 (depends on 1)

Process according to claim 1 wherein a comonomer is additionally placed in the vessel before the start of the polycondensation step.

### Claim 10 (depends on 9)

Process according to claim 9, wherein the comonomer is isophthalic acid, cyclohexane dimethanol or mixtures thereof.

### Claim 11 (depends on 1)

Process according to claim 1 wherein phosphoric acid in an amount of about 10 to about 30 ppm is added to the vessel.

### Claim 12 (depends on 1)

Process according to claim 1 wherein at least one color correction is added to the vessel.

### Claim 13 (depends on 12)

Process according to claim 12 wherein the color correction is cobalt acetate and/or blue toner.

### Claim 14 (depends on 1)

Process according to claim 1 wherein the catalyst components are placed in the vessel together before, during or after the esterification step.

### Claim 15 (depends on 1)

Process according to claim 1 wherein the catalyst components are placed in the vessel separately and at different times before, during or after the esterification step.