# US 11,028,047 B2 · Method for recovering dimethyl sulfoxide from recovered resist remover

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- Number: US 11,028,047 B2
- Document ID: US11028047B2
- Status: Granted
- Kind: B2
- Application number: 16/630,630
- Filed: 2018-07-31
- Published: 2020-04-30
- Granted: 2021-06-08
- Earliest claimed: 2017-08-02
- Assignees: Kuraray Co., Ltd.
- Applicants: Kuraray Co., Ltd.
- Inventors: Kunio Mayahara; Koji Tamura; Akinobu Takeda
- Web page: https://patentgrep.com/patent/US11028047B2

## CPC

- B01D 3/38: Steam distillation
- C07C 315/06: Separation; Purification; Stabilisation; Use of additives
- B01D 3/34: with one or more auxiliary substances
- Y02W 30/62: Plastics recycling; Rubber recycling
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A method for recovering dimethyl sulfoxide, including a step of contacting a recovered resist remover containing at least one compound selected from the group consisting of glycol ether, glycol and triol, and dimethyl sulfoxide with water and performing distillation.

## Claims

### Claim 1

A method for recovering dimethyl sulfoxide from a composition, the method comprising:
contacting the composition with water, where the composition comprises at least one compound selected from a group consisting of glycol ethers, glycols, and triols, and dimethyl sulfoxide;
and performing distillation on the composition contacted with water to recover a purified dimethyl sulfoxide product,
wherein an amount of the water contacted with the composition is from 0.1 to 100 parts by mass with respect to 1 part by mass of the composition.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the at least one compound is selected from a group consisting of 3-methoxy-3-methyl-1-butanol, diethylene glycol, propylene glycol, glycerin and 2-(2-methoxyethoxy)ethanol.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the at least one compound is 3-methoxy-3-methyl-1-butanol.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the composition is a resist remover that has been used to wash and remove an unnecessary resist film in photolithography.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the composition further comprises a quaternary ammonium hydroxide, a resist component, or both.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the composition further comprises at least one other component selected from a group consisting of water, alkanolamines, amino acids, surfactants, and antifoaming agents.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the distillation is performed such that the purified dimethyl sulfoxide product has a purity of 99.9%.

### Claim 8 (depends on 1)

The method according to claim 1, wherein a purity of the purified dimethyl sulfoxide product obtained by the distillation is higher than a purity of a dimethyl sulfoxide product obtained by distilling the composition without contacting with water.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the distillation is performed at a temperature of from 104 to 250° C.