Hydrochloric acid purification process

Patent metadata

Field	Value
Publication number	US-9828314-B2
Application number	US-201415039294-A
Country	US
Kind code	B2
Filing date	Nov 10, 2014
Priority date	Nov 28, 2013
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

The invention relates to a process for the treatment of a gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated/oxygenated compounds, in which the gas stream is successively subjected to:
a stage of catalytic hydrolysis; a stage of washing with an acid solution; a stage of adsorption of impurities by active charcoal; a stage of adiabatic or isothermal absorption of the hydrochloric acid in an aqueous solution, making it possible to collect hydrochloric acid solution.

First claim

The invention claimed is:

1. A process for treating a gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated-oxygenated compound, comprising successively subjecting the gas stream to the following stages:
hydrolyzing in the presence of a catalyst;
washing with acid solution;
adsorbing impurities by active charcoal; and
absorbing the hydrochloric acid in an aqueous solution by adiabatic or isothermal absorption to collect hydrochloric acid solution;
wherein the fluorinated-oxygenated compound comprises carbonyl difluoride, carbonyl chloride fluoride, trifluoroacetyl fluoride and/or trifluoroacetic acid.

2. The process of claim 1 , wherein the catalytic hydrolysis stage is carried out on a bed of active charcoal.

3. The process of claim 1 , wherein the acid solution used during the washing stage is a hydrochloric acid solution.

4. The process of claim 1 , further comprising subjecting the gas stream to a stage of bringing the hydrochloric acid solution into contact with a silica gel.

5. The process of claim 1 , wherein boric acid is added to the acid solution used for the washing stage.

6. The process of claim 1 , wherein the gas stream is a stream resulting from a catalytic fluorination reaction of at least one chlorinated compound to give at least one fluorinated compound.

7. The process of claim 6 , wherein the catalytic fluorination reaction is carried out in the presence of oxygen.

8. The process of claim 6 , wherein the chlorinated compound comprises a chlorocarbon, a hydrochlorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a chloroolefin, a hydrochloroolefin, a chlorofluoroolefin or a hydrochlorofluoroolefin and wherein the fluorinated compound comprises a fluorocarbon, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a fluoroolefin, a hydrofluoroolefin, a chlorofluoroolefin or a hydrochlorofluoroolefin.

9. A process for preparing a fluorinated compound, comprising:
providing a chlorinated compound and hydrofluoric acid;
catalytically reacting the chlorinated compound with the hydrofluoric acid and collecting a stream of crude products;
separating the stream of crude products to recover a stream comprising fluorinated compound and a gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated-oxygenated compound comprising carbonyl difluoride, carbonyl chloride fluoride, trifluoroacetyl fluoride and/or trifluoroacetic acid; and
treating the gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated-oxygenated compound as in claim 1 .

10. The process of claim 9 , wherein the catalytic reaction is carried out in the presence of oxygen.

11. The process of claim 9 , wherein the chlorinated compound comprises a chlorocarbon, a hydrochlorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a chloroolefin, a hydrochloroolefin, a chlorofluoroolefin or a hydrochlorofluoroolefin and wherein the fluorinated compound comprises a fluorocarbon, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a fluoroolefin, a hydrofluoroolefin, a chlorofluoroolefin or a hydrochlorofluoroolefin.

Assignees

• Arkema France

Inventors

• Collier Bertrand
• Deur-Bert Dominique
• Lacambra Joaquin
• Pigamo Anne

Classifications

• C01B7/0718

  by adsorption · CPC title

• C07C17/25

  by splitting-off hydrogen halides from halogenated hydrocarbons · CPC title

• B01D53/8662

  Organic halogen compounds · CPC title

• Y02C20/30

  of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6] · CPC title

• C07C19/10

  and chlorine · CPC title