# US 5,345,004 A · Process for the preparation of 1,3-butylene glycol

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- Number: US 5,345,004 A
- Document ID: US5345004A
- Status: Granted
- Kind: A
- Application number: 08/163,308
- Filed: 1993-12-08
- Granted: 1994-09-06
- Earliest claimed: 1993-03-24
- Assignees: Daicel Chemical Industries, Ltd.
- Inventors: Kazuhisa Nishiguchi
- Web page: https://patentgrep.com/patent/US5345004A

## CPC

- C07D 319/06: not condensed with other rings
- C07C 29/132: by reduction of an oxygen containing functional group
- C07C 29/141: with hydrogen or hydrogen-containing gases
- C07C 29/80: by distillation
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Disclosed are the improvements of a process for the preparation of 1,3-butylene glycol, in which the generation of by-products can be decreased, resulting in being capable of producing 1,3-butylene glycol having high quality (e.g. an odorless, so-called "cosmetic grade") at a high-yield.

## Claims

### Claim 1

A process for the preparation of 1,3-butylene glycol by steps (a), (b) and (c);
(a) aldol condensation step of acetaldehyde in the presence of an alkali catalyst to obtain a crude reaction solution primarily containing aldoxane, acetaldehyde, water and small amounts of croton aldehyde;
(b) thermal decomposition step of aldoxane to obtain paraldol while distilling off a distillate containing acetaldehyde, water and small amounts of croton aldehyde from the crude reaction solution;
(c) hydrogenation step of paraldol to obtain 1,3-butylene glycol in the presence of a catalyst;
characterized in that a refined acetaldehyde not containing a substantial amount of croton aldehyde is recirculated to step (a) after removal of croton aldehyde from the distillate in step (b).

### Claim 2 (depends on 1)

A process as set forth in claim 1, wherein said removal of croton aldehyde is carried out in an acetaldehyde distillation column having a side-stream recirculating line equipped with a decanter.

### Claim 3

A process for the preparation of 1,3-butylene glycol by steps (a), (b) and (c);
(a) aldol condensation step of acetaldehyde in the presence of an alkali catalyst to obtain a crude reaction solution primarily containing aldoxane, acetaldehyde, water and small amounts of croton aldehyde;
(b) thermal decomposition step of aldoxane to obtain paraldol while distilling off a distillate containing acetaldehyde, water and small amounts of croton aldehyde from the crude reaction solution;
(c) hydrogenation step of paraldol to obtain 1,3-butylene glycol in the presence of a catalyst;
characterized in that water is charged into the aldoxane decomposition column in step (b).

### Claim 4 (depends on 3)

A process as set forth in claim 3, wherein said water is water discharged from the bottom of an acetaldehyde distillation column.

### Claim 5 (depends on 3, 4)

A process as set forth in claim 3 or 4, wherein the water to be charged into the aldoxane decomposition column is selected from fresh water and water from the bottom of the acetaldehyde refining column.

### Claim 6 (depends on 3, 4, 5)

The process of any one of claims 3 to 5, wherein the water contents range in the stream (B) is maintained at more than 5 weight %.

### Claim 7 (depends on 3, 4, 5)

The process of any one of claims 3 to 5, wherein the water contents range in the stream (B) is maintained at more than 10 weight %.

### Claim 8 (depends on 3, 4, 5)

The process of any one of claims 3 to 5, wherein the water contents range in the stream (B) is maintained at more than 20 weight %.

### Claim 9

A process for the preparation of 1,3-butylene glycol by steps (a), (b) and (c);
(a) aldol condensation step of acetaldehyde under the presence of an alkali catalyst to obtain a crude reaction solution primarily containing aldoxane, acetaldehyde, water and small amounts of croton aldehyde;
(b) thermal decomposition step of aldoxane to obtain paraldol while distilling off a distillate containing acetaldehyde, water and small amounts of croton aldehyde from the crude reaction solution;
(c) hydrogenation step of paraldol to obtain 1,3-butylene glycol in the presence of a catalyst;
characterized in that fresh water is charged into the top of a distillation column while removing water after having removed ethanol and butanol from a crude 1,3-butylene glycol solution containing ethanol and butanol obtained in said hydrogenation step (c).

### Claim 10 (depends on 9)

The process of claim 9, wherein said fresh water is deionized water.

### Claim 11 (depends on 9, 10)

The process of claim 9 or 10, wherein said fresh water is charged in the top portion of the water-distillation column from 1 to 200 parts by weight, based on the amount of the crude liquid to be charged.

### Claim 12 (depends on 9, 10)

The process of claim 9 or 10, wherein said fresh water is charged in the top portion of the water-distillation column from 5 to 50 parts by weight, based on the amount of crude liquid to be charged.