# US 9,517,934 B2 · Process for the generation of chlorine dioxide

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- Number: US 9,517,934 B2
- Document ID: US9517934B2
- Status: Granted
- Kind: B2
- Application number: 14/201,964
- Filed: 2014-03-10
- Published: 2016-03-10
- Granted: 2016-12-13
- Earliest claimed: 2013-03-14
- Assignees: The United States of America as represented by the Secretary of the Army
- Applicants: The United States of America as Represented by the Secretary of the Army
- Inventors: Christopher J. Doona; Kenneth Kustin
- Web page: https://patentgrep.com/patent/US9517934B2

## CPC

- C01B 11/024: {from chlorites}
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}

## Abstract

The present invention in one embodiment provides a process of generating chlorine dioxide by reacting formamidinesulfinic acid (FSA) and sodium chlorite in an aqueous solution.

## Claims

### Claim 1

A process of generating chlorine dioxide, comprising the steps of: adding formamidinesulfinic acid (FSA) and sodium chlorite to water to form an aqueous solution having a pH of 6-8 and reacting the FSA and the sodium chlorite at the pH of 6-8 to produce chlorine dioxide based on an oxidation-reduction reaction of chlorite and the sulfur-containing compound FSA, wherein the reacting produces chlorine dioxide having a concentration of at least 1 parts per million (ppm) in less than or equal to 30 seconds of adding the FSA and the sodium chlorite to the aqueous solution.

### Claim 2 (depends on 1)

The process of claim 1 wherein the amount of chlorite is in excess of the amount of FSA such that the mole ratio of chlorite to FSA is in the range of about {(2-161) mole chlorite}:{1 mol FSA}.

### Claim 3 (depends on 2)

The process of claim 2 wherein the amount of sodium chlorite is between 0.7-2.7 g and the amount of FSA is between 0.1-0.65 g, respectively.

### Claim 4 (depends on 1)

The process of claim 1 wherein the amount of water is in excess of the amount of chlorite such that the mole ratio of water to chlorite is in the range of about {(27-8658) mole water}:{1 mole chlorite}.

### Claim 5 (depends on 4)

The process of claim 4 wherein the volume of water ranges from 15-1200 mL.

### Claim 6 (depends on 1)

The process of claim 1 including a pH buffering agent.

### Claim 7 (depends on 6)

The process of claim 6 wherein the buffering agent is selected from the group consisting of sodium phosphate, monobasic dehydrate, sodium phosphate dibasic, sulfate, citrate, sulfamate, and meta-bisulfite.

### Claim 8 (depends on 1)

The process of claim 1 wherein the amount of sodium chlorite is in excess of the amount of FSA.

### Claim 9 (depends on 1)

The process of claim 1 wherein the moles of water are in excess of the moles of sodium chlorite.

### Claim 10 (depends on 1)

The process of claim 1 wherein the FSA is produced by the chemical reaction of an FSA precursor to produce FSA.

### Claim 11 (depends on 10)

The process of claim 10 wherein FSA precursor is selected from the group consisting of thiourea, formamidinesulfenyl acid, and formamidinesulfonic acid.

### Claim 12 (depends on 11)

The process of claim 11 wherein the FSA is produced by chemical reaction of an FSA precursor with an oxidant, said oxidant selected from the group consisting of bromine, bromite, hypobromous acid, bromate, iodate, iodine, persulfate, and hydrogen peroxodisulfate.

### Claim 13 (depends on 1)

The process of claim 1 further comprising the step of transporting the generated aqueous chlorine dioxide from the solution phase to the gaseous phase.

### Claim 14 (depends on 1)

The process of claim 1 where the FSA and the sodium chlorite are mixed together in the form of loose powders, granules, compressed pellets, or tablets.

### Claim 15 (depends on 1)

The process of claim 1 wherein the chlorine dioxide concentration produced is biocidal.