# US 2014/0155644 A1 · Separating cyclic siloxanes from short-chain siloxanes having terminal hydroxyl groups

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- Number: US 2014/0155644 A1
- Document ID: US20140155644A1
- Status: Published application
- Kind: A1
- Application number: 14/233,070
- Filed: 2012-07-11
- Published: 2014-06-05
- Earliest claimed: 2011-07-25
- Assignees: Wacker Chemie AG
- Inventors: Alfred Popp; Christine Kaes; Klaus Kaeppler; Ulrike Buettner
- Web page: https://patentgrep.com/patent/US20140155644A1

## CPC

- C07F 7/21: Cyclic compounds having at least one ring containing silicon, but no carbon in the ring
- C08G 77/16: to hydroxy groups
- C08G 77/34: Purification
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

Cyclic siloxanes are separated from short chain hydroxyl-terminated siloxanes by contact with steam at at least 650 hPa absolute. The cyclic siloxanes and other components which are separated by use of steam can be recovered by phase separation, and preferably used in other processes.

## Claims

### Claim at position 1

1-4. (canceled)

### Claim 5

A method for removing cyclic siloxanes from a mixture which contains cyclic siloxanes of the formula (I)
(R1R2SiO)m (I),
where
R1 are alkyl groups having 1 to 12 carbon atoms,
R2 have the meanings of R1, or are aryl groups having 5 to 30 carbon atoms or alkenyl groups having 2 to 12 carbon atoms, and
m is an integer of from 3 to 20,
and which contains short-chain siloxanes having terminal hydroxyl groups, comprising separating the cyclic siloxanes using a steam stream at at least 650 hPa absolute, where the remaining fraction of cyclic siloxanes in the mixture, based on the sum of cyclic siloxanes of the formula (I) in which m =4 to 6, is in a range of 0-20,000 ppm by weight.

### Claim 6 (depends on 5)

The method of claim 5, wherein the short-chain siloxanes having terminal hydroxyl groups have the formula (II)
HO(R3R4SiO)nH (II),
where
R3 are alkyl group having 1 to 12 carbon atoms,
R4 have the meanings of R3, or are aryl groups having 5 to 30 carbon atoms or alkenyl groups having 2 to 12 carbon atoms, and
n is an integer from 2 to 100.

### Claim 7 (depends on 5)

The method of claim 5, wherein the pressure is 800 hPa to 5000 hPa absolute.

### Claim 8 (depends on 6)

The method of claim 6, wherein the pressure is 800 hPa to 5000 hPa absolute.

### Claim 9 (depends on 5)

The method of claim 5, wherein the temperature is from 100° C. to 200° C.

### Claim 10 (depends on 6)

The method of claim 6, wherein the temperature is from 100° C. to 200° C.

### Claim 11 (depends on 7)

The method of claim 7, wherein the temperature is from 100° C. to 200° C.

### Claim 12 (depends on 8)

The method of claim 8, wherein the temperature is from 100° C. to 200° C.