# US 5,703,228 A · Process for the purification of carbohydrate derivatives with surface-active properties

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- Number: US 5,703,228 A
- Document ID: US5703228A
- Status: Granted
- Kind: A
- Application number: 08/598,348
- Filed: 1996-02-08
- Granted: 1997-12-30
- Earliest claimed: 1995-02-08
- Assignees: SKW Trostberg Aktiengesellschaft
- Inventors: Jurgen Heidlas; Jan Cully
- Web page: https://patentgrep.com/patent/US5703228A

## CPC

- C07H 15/04: attached to an oxygen atom of the saccharide radical
- C07H: SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS (derivatives of aldonic or saccharic acids C07C, C07D; aldonic acids, saccharic acids C07C59/105, C07C59/285; cyanohydrins C07C255/16; glycals C07D; compounds of unknown constitution C07G; polysaccharides, derivatives thereof C08B; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; sugar industry C13)

## Abstract

A process is described for the purification of carbohydrate derivatives with surface-active properties in which an extraction process is used to liberate the solid or liquid starting material from undesired lipophilic by-products by the use of compressed propane or a proportionate mixture thereof with butane at pressures between 8 and 150 bar and a process temperature below 120.degree. C. In this way it is possible to isolate valuable raw materials in a gentle manner either batch-wise or continuously which meet the high purity requirements, for example in the field of cosmetics.

## Claims

### Claim 1

A process for the purification of a carbohydrate derivative with surface-active properties, comprising: extracting a starting material containing the carbohydrate derivative and impurities with an extraction medium comprising compressed propane or mixtures thereof containing up to 25% by weight butane at pressures between 8 and 150 bar and a temperature of less than 120.degree. C. whereby the impurities are separated from the carbohydrate derivative.

### Claim 2 (depends on 1)

The process of claim 1 wherein the pressure is between 20 and 80 bar.

### Claim 3 (depends on 1)

The process of claim 1, wherein the impurities have a higher solubility in the extraction medium than the carbohydrate derivatives.

### Claim 4 (depends on 1)

The process of claim 1, wherein the starting material is solid and is subjected batch-wise to a solid/liquid extraction.

### Claim 5 (depends on 1)

The process of claim 1, wherein the starting material is liquid (liquified) and is subjected to a liquid/liquid extraction.

### Claim 6 (depends on 5)

The process of claim 5, wherein the extraction is carried out in a countercurrent manner.

### Claim 7 (depends on 5)

The process of claim 5, wherein the extraction is carried out in a separation column with a temperature gradient of .DELTA.T less than or equal to 20.degree. C. that increases towards the top of the column.

### Claim 8 (depends on 1)

The process of claim 1, wherein 3 to 15 grams of compressed gas (mixture) is used per gram of starting material to be extracted.

### Claim 9 (depends on 1)

The process of claim 1, wherein the carbohydrate derivative is obtained by reducing the pressure and/or increasing the temperature during which the extraction medium is converted into a gaseous state.

### Claim 10 (depends on 1)

The process of claim 1, wherein the extraction medium is recycled.

### Claim 11 (depends on 1)

The process of claim 1, wherein the carbohydrate derivatives are selected from mono-, di- and/or oligosaccharidic carbohydrates having lipophilic groups.

### Claim 12 (depends on 11)

The process of claim 11, wherein the carbohydrate derivatives are carbohydrate esters, carbohydrate ethers, esterified carbohydrate ethers or mixtures thereof.

### Claim 13 (depends on 1)

The process of claim 1, wherein lipophilic substances are separated as impurities.

### Claim 14 (depends on 13)

The process of claim 13 wherein the lipophilic substances comprise at least one of fatty acids, fatty acid esters, glycerides and fatty alcohols .