# US 2018/0022682 A1 · Method for esterification of a diol using a reactive distillation

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2018/0022682 A1
- Document ID: US20180022682A1
- Status: Published application
- Kind: A1
- Application number: 15/551,754
- Filed: 2016-02-17
- Published: 2018-01-25
- Earliest claimed: 2015-02-18
- Assignees: Ifp Energies Nouvelles; Compagnie Generale Des Etablissements Michelin
- Applicants: IFP Energies Nouvelles; Compagnie Generale des Etablissements Michelin
- Inventors: Romain RICHARD; Damien LEINEKUGEL LE COCQ; Marc JACQUIN; Margarita DORATO; Nuno PACHECO; Claire RANNOUX
- Web page: https://patentgrep.com/patent/US20180022682A1

## CPC

- C07C 67/08: by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
- C07C 1/213: by splitting of esters
- C07C 67/54: by distillation
- C07C 67/58: by liquid-liquid treatment
- C07C 69/08: of dihydroxylic compounds
- C07C 69/16: of dihydroxylic compounds
- C07C 69/28: esterified with dihydroxylic compounds
- Y02P 20/10: Process efficiency
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The invention relates to a conversion method that is fed with a diol feedstock that comprises at least 90% by weight of diol and a carboxylic acid feedstock that comprises at least 80% by weight of carboxylic acid. The method comprising at least: An esterification step which is fed with at least the diol feedstock and at least the carboxylic acid feedstock, wherein the carboxylic acid/diol molar ratio at the inlet of the esterification step is between 2 and 6, the esterification step comprises at least one reactive distillation column that has a mixed reaction/separation zone located between two separation zones; and A water elimination step that is fed with distillate from the esterification step that comprises water and producing at least one water effluent.

## Claims

### Claim 1

Conversion method that is fed with a diol feedstock that comprises at least 90% by weight of diol and a carboxylic acid feedstock that comprises at least 80% by weight of carboxylic acid, with said method comprising at least:
An esterification step, fed with at least said diol feedstock and at least said carboxylic acid feedstock, with the feed flow rates being adjusted in such a way that the carboxylic acid/diol molar ratio at the inlet of said esterification step is between 2 and 6, with said esterification step comprising at least one reactive distillation column operated at a temperature of between 40 and 280° C., at a pressure of between 0.01 and 0.5 MPa, with a molar reflux rate of between 0.5 and 10, and a molar reboil rate of between 0.5 and 10, consisting of a mixed reaction/separation zone located between two separation zones, with each of said separation zones having an effectiveness of at least two theoretical stages, said mixed zone comprising an acid heterogeneous catalyst, said esterification step producing at least one distillate that comprises water and a diol-diester residue;
A water elimination step that is fed with said distillate comprising water and producing at least one water effluent.

### Claim 2 (depends on 1)

Conversion method according to claim 1, in which the carboxylic acid/diol molar ratio at the inlet of said esterification step is between 2 and 4.

### Claim 3 (depends on 1)

Conversion method according to claim 1, in which the dwell time in said reactive distillation column, defined as the volume of the reactive distillation divided by the volumetric flow rate of said diol feedstock and said carboxylic acid feedstock, is between 0.5 h and 10 h.

### Claim 4 (depends on 1)

Conversion method according to claim 1, in which said water elimination step comprises a heterogeneous azeotropic distillation section that is operated in the presence of a driver such as ether, ester, ketone, or hydrocarbon, comprising:
A first heterogeneous azeotropic distillation column that is fed with said distillate that comprises water and that produces a distillate that comprises the water/driver azeotrope and a carboxylic acid residue;
A decanter that is fed with said distillate that comprises the water/driver azeotrope and that produces a water-rich phase and a driver-rich phase, with said driver-rich phase being recycled as reflux from said first heterogeneous azeotropic distillation column;
A second heterogeneous azeotropic distillation column that is fed with said water-rich phase, which produces a distillate that is recycled to said decanter and a water residue.

### Claim 5 (depends on 1)

Conversion method according to claim 1, in which said water elimination step comprises:
A liquid-liquid extraction section that is fed at the top with said distillate that comprises water and at the bottom with a driver such as ether, ester, ketone, or hydrocarbon and that produces an extract at the top and a raffinate at the bottom;
A first heterogeneous azeotropic distillation column that is fed with said extract and that produces a distillate that comprises the water/driver azeotrope and a carboxylic acid residue;
A second heterogeneous azeotropic distillation column that is fed with said raffinate and that produces a distillate that comprises the water/driver azeotrope and a water residue;
A decanter that is fed with said distillate that comprises the water/driver azeotrope that is obtained from said first column and with said distillate that comprises the water/driver azeotrope that is obtained from said second column and that produces a water-rich phase and a driver-rich phase, with said driver-rich phase being reycled as reflux from said first column and said water-rich phase being recycled as reflux from said second column.

### Claim 6 (depends on 1)

Conversion method according to claim 1, in which said esterification step and said water elimination step are coupled, with said esterification step also being fed with a driver, which brings about a separation between a water-rich phase and a driver-rich phase in the condenser of said reactive distillation column, with said water-rich phase feeding a distillation column that produces a water residue and a distillate, which is recycled in said condenser of said reactive distillation column, with said driver being an ether, a ketone, or a hydrocarbon.

### Claim 7 (depends on 1)

Conversion method according to claim 1, in which said driver is MEK.

### Claim 8 (depends on 1)

Conversion method according to claim 1, also comprising a pyrolysis step that comprises:
A pyrolysis reactor that is fed with said diol-diester residue from said esterification step that is carried out at a temperature of between 500 and 650° C. and that produces a pyrolysis effluent;
At least one separation section in which said pyrolysis effluent is cooled to a temperature that is lower than 100° C. in such a way as to produce at least one liquid pyrolysis effluent and a vapor pyrolysis effluent, which is separated into a light compound effluent and a diolefin effluent.

### Claim 9 (depends on 8)

Conversion method according to claim 8, in which said liquid pyrolysis effluent is mixed with said carboxylic acid feedstock that feeds said conversion method.

### Claim 10 (depends on 1)

Conversion method according to claim 1, in which said diol is selected from among the butanediols, pentanediols, and hexanediols.

### Claim 11 (depends on 1)

Conversion method according to claim 1, in which said diol is selected from among 2,3-butanediol, 1,3-butanediol, and 1,4-butanediol.

### Claim 12 (depends on 1)

Conversion method according to claim 1, in which said esterification step also comprises a pre-esterification section that is fed with said diol feedstock and a fraction of said carboxylic acid feedstock and that produces a pre-esterified diol feedstock, used in a fixed bed in the presence of a heterogeneous acid catalyst, with said pre-esterification section being operated at a pressure of between 0.01 and 0.5 MPa, and at a temperature of between 80° C. and 170° C.

### Claim 13 (depends on 1)

Conversion method according to claim 1, in which said carboxylic acid is selected from among the aliphatic carboxylic acids.

### Claim 14 (depends on 13)

Conversion method according to claim 13, in which said carboxylic acid is selected from among formic acid, acetic acid, propanoic acid, and butanoic acid.