Method for manufacturing methyl fluoride

Patent metadata

Field	Value
Publication number	US-9919990-B2
Application number	US-201414909156-A
Country	US
Kind code	B2
Filing date	Aug 7, 2014
Priority date	Aug 9, 2013
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An object of the present invention is to provide a method for producing methane fluoride that is useful, for example, as a dry etching gas, the method being more suitable for industrial production. To achieve this object, the present invention provides a method including reacting (A) dimethyl sulfate and (B) at least one fluorocompound in a liquid phase, the fluorocompound (B) being at least one compound selected from the group consisting of hydrogen fluoride and hydrofluoric acid salts, or a metal fluoride, wherein when the fluoride compound (B) includes hydrogen fluoride or a hydrofluoric acid salt, the reaction is carried out without a solvent or using a polar solvent as a solvent, and when the fluoride compound (B) is a metal fluoride, the reaction is carried out using water as a solvent.

First claim

The invention claimed is:

1. A method for producing methane fluoride (CH 3 F) comprising reacting
(A) dimethyl sulfate and
(B) at least one fluorocompound in a liquid phase, the fluorocompound being a metal fluoride or at least one member selected from the group consisting of hydrogen fluoride and hydrofluoric acid salts,
wherein:
the molar ratio of the fluorocompound (B) to dimethyl sulfate (A) is from 22 to 50, and
when the fluorocompound (B) is a metal fluoride, the reaction is carried out using a solvent consisting of water, and when the fluorocompound (B) includes hydrogen fluoride or a hydrofluoric acid salt, the reaction is carried out without a solvent or using a solvent consisting of water,
wherein when the solvent consisting of water is used, a mixture of the fluorocompound (B) with the solvent consisting of water is prepared and then dimethyl sulfate (A) is gradually added to the mixture at 0.5 to 50 mL/h.

2. The method according to claim 1 , wherein the metal fluoride is at least one metal fluoride of formula (1):
MF  (1)

wherein M represents an alkali metal or an alkaline earth metal.

3. The method according to claim 1 , wherein the hydrofluoric acid salt is at least one hydrofluoric acid salt of formula (2) or (3):

wherein R 2 , R 3 , and R 4 are the same or different and each represents hydrogen or an alkyl or cycloalkyl group that may be substituted with at least one halogen atom, and n is an integer of 1 to 5, or

wherein R 5 , R 6 , and R 7 may be the same or different, and each represents hydrogen or an alkyl or cycloalkyl group that may be substituted with at least one halogen atom, and n is an integer of 1 to 5.

4. The method according to claim 3 , wherein the hydrofluoric acid salt of formula (2) is ammonium fluoride (NH 4 F), ammonium hydrogen difluoride (NH 4 FHF), methylamine fluoride (CH 3 NH 3 F), ethylamine fluoride (C 2 H 5 NH 3 F), butylamine fluoride (C 4 H 9 NH 3 F), dimethylamine fluoride ((CH 3 ) 2 NH 2 F), diethylamine fluoride ((C 2 H 5 ) 2 NH 2 F), triethylamine fluoride ((C 2 H 5 ) 3 NHF), or triethylamine trihydrofluoride ((C 2 H 5 ) 3 N.3HF), and/or the hydrofluoric acid salt of formula (3) is a pyridine hydrofluoric acid salt.

5. The method according to claim 1 , wherein the reaction is carried out without a solvent using hydrogen fluoride as the fluorocompound (B).

6. The method according to claim 5 , wherein the reaction is carried out using hydrogen fluoride in a state liquefied by pressure.

7. The method according to claim 1 , wherein the reaction is carried out using a metal fluoride and/or a hydrofluoric acid salt as the fluorocompound (B) and using a solvent consisting of water.

8. The method according to claim 7 , wherein the reaction is carried out by adding dimethyl sulfate (A) dropwise to an aqueous solution of the fluorocompound (B) in water.

Assignees

• Daikin Ind Ltd

Inventors

• Nakamura Shingo
• Fukumoto Kanako
• Etou Yuusuke
• Ohtsuka Tatsuya
• Higashi Masahiro

Classifications

• C07C17/093

  by replacement by halogens · CPC title

• C07C17/07

  by addition of hydrogen halides · CPC title

• C07C17/361 Primary

  by reactions involving a decrease in the number of carbon atoms · CPC title

• C07C19/08

  containing fluorine · CPC title