WO2011086579A1

WO2011086579A1 - Process for producing stable and pure liquid form of chlorine dioxide

Info

Publication number: WO2011086579A1
Application number: PCT/IN2011/000024
Authority: WO
Inventors: Devesh Patel; Manish Ghadia
Original assignee: Prophylaxis
Priority date: 2010-01-18
Filing date: 2011-01-13
Publication date: 2011-07-21

Abstract

The present invention provides a process to produce stable & pure liquid chlorine dioxide (CIO₂). Liquid chlorine dioxide obtained in the present invention having concentration between 500 ppm (0.05%) to 50000 ppm (5.0%) as stable and purity >99% and generates no harmful by-products and effective in broad pH range from 4 to 10. Process for the preparation of liquid chlorine dioxide comprises two components system i.e. Sodium Salt Textone (Sodium Chlorite, NaCIO₂) and Sodium Peroxydisulphate (Sodium Persulphate, Na₂S₂O₈) or Sodium Hydrogen Sulphate (Sodium Bisulphate,NaHS04) in watery solution, each component having shelf life of more than 2 year. Moreover, the process does not form any undesired by-products, particularly MX(Mutagen X), THM(Tri Halo Methanes), HAA(Halo Acetic Acids), Alkali metal sulfates, Chlorites, Chlorates, free Chlorine, Chloramines etc. The end products are a fraction of Sodium Sulphate (Na₂SO₄) and Sodium Chloride (NaCI). These substances are most common in water. Process does not employ any type of generator for production of CIO₂. The process can be performed at any place, has almost no explosion hazards. Liquid chlorine dioxide obtained using the said process having shelf life as per kinetic half time >30 days.

Description

PROCESS FOR PRODUCING STABLE AND PURE LIQUID FORM OF CHLORINE DIOXIDE

The present invention relates to a process for producing stable and pure liquid form of chlorine dioxide.

The process of producing pure form of liquid chlorine dioxide involves two components system in liquid solution without formation of any harmful byproducts.

State of the art:

Chlorine dioxide, in recent years, has achieved considerable commercial significance in the field of pulp bleaching, water purification, fat bleaching, removal of phenols from industrial wastes, textile bleaching and certain other oxidizing procedures. Chlorine dioxide is highly active chemical which has been widely used in variety of processes such as disinfecting, sterilizing, viricidal, algicidal, fungicidal and bactericidal applications. Usually it is necessary to generate chlorine dioxide at the point of use, because of its explosive nature at higher concentrations and the attendant difficulty at transportation.

Chlorine dioxide has numerous applications in various fields, such as in municipal water treatment; industrial water treatment; electronics; disinfection & microbiological control, odor control, sanitation in food & beverages; Oil and gas industries; environmental control; textile industries; hospitals; in cooling towers; in sea food industries; Dairy industries; Poultry industries; Meat industries; Hotel industries; Swimming pools & spa; etc.

Chlorine dioxide is usually produced as a watery solution or gas. Chlorine dioxide cannot be stored for too long, because it slowly dissociates into chlorine and oxygen. It is rarely stored as a gas, because it is explosive under pressure. Procedures for the manufacture of chlorine dioxide which have been previously proposed require very careful control of reaction conditions, often utilizing expensive reducing agents or require rather expensive elaborate equipment, to obtain a good yield of chlorine dioxide. US 2,163,793 patent describes an electrochemical chlorine dioxide generating process in which a mixture of alkali metal chlorite and alkali metal chloride is electrolyzed in an electrolytic cell equipped with a porous diaphragm separating the anode and the cathode compartments.

U.S. Patent No. 2,678,922 prepares an aqueous solution of chlorine dioxide and flushes the chlorine dioxide from the solution with air. The chlorine dioxide-air stream is passed through liquid chlorine to provide a liquid chlorine/chlorine dioxide solution. British Patent No. 714,828 describes a process for the production of chlorine dioxide by electrolysing an aqueous solution containing chlorite and a water soluble salt of an inorganic oxy-acid other than sulfuric acid while U.S. Pat. No. 2,717,237 discloses a method for producing chlorine dioxide by electrolysis of chlorite in the presence of sulfate ions. Several suppliers offer a liquid called "Stabilized Chlorine Dioxide", "Chlorine Dioxide Solution" or similar names. These materials are not chlorine dioxide, but dissolved sodium chlorite. When mixed with acid, they produce chlorine dioxide solutions, but this requires chemical mixing and handling of acid. Opportunities abound for errors in mixing and even when reagents are mixed properly the resulting solution may contain high levels of salt, acid, and other impurities. Moreover, after mixing, the chlorine dioxide solutions have a short shelf life.

Gaseous chlorine dioxide is also becoming art increasingly important disinfectant. The chlorine dioxide gas has been used for many years to sterilize medical instruments and other medical articles as described in US Patent 4,681 ,739. Gaseous chlorine dioxide has also been used to decontaminate buildings containing Anthrax spores after the Anthrax attacks of 2001 . The gas reportedly has been commonly used for decontamination of buildings infested with mold. It is also being introduced as a decontaminant for bio-safety cabinets and other laboratory enclosures.

US Patent No. 5,234,678 has enabled the simple and safe production of high purity chlorine dioxide gas. This process involves the reaction of a solid granular sodium chlorite with dilute chlorine gas. Unlike the liquid phase production methods, the product resulting from this process does not contain significant quantities of sodium chlorite, sodium chlorate, or substantial quantities of sodium chloride, since these materials do not form gases to any appreciable extent. Laboratory tests shown that the chlorine dioxide gas produced from this process can be over 99.95% pure.

The use of highly pure chlorine dioxide gas as an oxidizer and disinfectant has been limited because chlorine dioxide is unstable in gas phase, and has been thought to have limited stability in aqueous solution. Chlorine dioxide gas can be toxic to humans at concentrations greater than 5 ppm, and it can be explosive at partial pressures of above 0.1 atmosphere. Therefore, chlorine dioxide gas is generally not manufactured and shipped under pressure like other industrial gases, and on-site manufacturing methods require not only expensive equipment, but also high levels of operator skill to avoid generating dangerously high concentrations.

All current commercial processes for generation of chlorine dioxide involve methods for combining sodium chlorate or sodium chlorite with acids or oxidizing agents in aqueous systems. The chlorine dioxide produced is isolated as an aqueous solution with concentrations varying from a few parts per million to over 9,000 parts per million. The process leading to this latter high concentration is an exception, and involves a recirculating loop to add new chlorine dioxide values to solutions already containing freshly generated chlorine dioxide.

So far I am aware; chlorine dioxide has not been available in stable liquid form for practical use because of its unstable, explosive nature.

In the present invention we have prepared, quite unexpectedly, chlorine dioxide in a stable liquid form with only moderate precautions. Summary of the invention:

The object of the invention is to provide a process to produce chlorine dioxide in stable and liquid form, which with moderate precautions and with safety be handled and stored. It is accordingly an object of the invention to provide a process to produce chlorine dioxide with high efficiency and high production rate. Liquid chlorine dioxide obtained in the present invention having concentration between 500 ppm (0.05%) to 50000 ppm (5.0%) as stable and pure form.

It is another object of the invention to provide a process of producing liquid chlorine dioxide having purity >99%, wherein no harmful byproduct is formed.

The other object of the invention is to provide a process for the preparation of liquid chlorine dioxide which requires two components system i.e. Sodium Salt Textone (NaCI0₂) and Sodium Peroxydisulphate (Na₂S₂0₈) or Sodium Hydrogen Sulphate (NaHS04) in watery solution. Moreover, in a watery solution chlorine dioxide remain stable and soluble. The other object of the present invention is to provide an efficient process of producing liquid chlorine dioxide without formation of undesired by-products, particularly MX(Mutagen X), THM(Tri Halo Methanes), HAA(Halo Acetic Acids), Alkali metal sulfates, Chlorites, Chlorates, free Chlorine, Chloramines, etc. Another object of the present invention is to provide a process to produce liquid form of chlorine dioxide without using generator.

Yet another object of the invention is to provide a process to generate liquid form of chlorine dioxide can be prepared at any place, has almost no explosion hazards.

Yet another object of the invention is to provide a process to prepare liquid chlorine dioxide having shelf life as per kinetic half time >30 days.

Other objects and advantages of the present invention will be apparent from the following detailed description. Detailed description of the invention:

The foregoing and other objects are accomplished by the practice of this invention. Broadly, viewed in one of its principal aspects, this invention consists of process to produce stable, pure liquid form of chlorine dioxide comprising: two components system in liquid solution, wherein the system is formed by a Sodium Salt Textone (Sodium Chlorite, NaCI0₂) and Sodium Peroxydisulphate (Sodium Persulphate, Na₂S₂0₈) or Sodium Hydrogen Sulphate (Sodium Bisulphate, NaHS0₄) component, in which Sodium Peroxydisulphate or Sodium Hydrogen Sulphate component is an activator to prepare stable & pure liquid chlorine dioxide, further the process does not generate any harmful byproduct.

In another embodiment of this invention, a process is provided to produce from 500 ppm (0.05%) to 50000 ppm (5.0%) stable & pure chorine dioxide in liquid form. Whereas, using liquid solution of NaHS0₄ in the process generate 2500 ppm (0.25%) to 25000 ppm (2.5%) liquid chlorine dioxide.

In accordance with the present invention herein illustrated and described, a process; of producing chlorine dioxide in a liquid form comprising the steps of: preparing liquid solution of liquid Sodium Salt Textone component & liquid solution of Sodium Peroxydisulphate component; HDPE (High density polyethylene) or glass or fiber glass quality container is filled with potable drinking water; adding liquid solution of components into water and closed it; the container is kept for 5-7 hours in dark place at room temperature for complete reaction to generate stable & pure liquid chlorine dioxide; before using the liquid chlorine dioxide it is stirred gently.

The present invention is further described with the process to produce >99% pure & stable liquid chlorine dioxide from the concentration between 500 ppm (0.05%) to 50000 ppm (5.0%). The said process comprises the steps of:

(A) Preparation of liquid solution of Sodium Salt Textone (Sodium chlorite):

8 part of liquid sodium salt textone (sodium chlorite) and 2 part potable drinking water are mixed properly in pure stainless steel vessel or glass or HDPE or PP (Polypropylene) vessels. The mixture is stirred at least 15 minutes for complete mixing.

80% NaCI0₂ + 20% H₂0 = 100% Sodium Salt Textone super concentrated liquid

We procure liquid form of sodium salt textone from the market of commercial grade having 25% purity. In addition to this, we have also attempted to prepare liquid sodium salt textone using crystal or powder form (50% - 80% pure) of sodium salt textone and the purity achieved for liquid form ranges from 25%-32%.

(B) Preparation of liquid solution of sodium peroxydisulphate (Sodium persulphate):

4 part of Sodium peroxydisulphate in crystal or powder form and 6 part of potable drinking water are mixed properly in glass vessels or fiber glass or HDPE or PP vessels. The mixture is stirred at least 25 minutes to dissolve solid particles. When dissolved Sodium peroxydisulphate would be about 70% to 75%, remaining 25% to 30% potable drinking water is added for complete mixing.

40% Na₂S₂0₈ + 60% H₂0 = 70% to 75% then add 25% to 30% H₂0 = Sodium peroxydisulphate super concentrated liquid

(C) Preparation of liquid chorine dioxide using liquid solution A & liquid solution B:

Container of HDPE / glass / fiber glass quality is filled with 90% of potable water. 5% of liquid solution obtained in step A is added into water, 5% of liquid solution obtained in step B is also added into water. Now container is closed properly and kept for at least 3-5 hours in dark place at room temperature for complete reaction to generate stable and pure liquid chlorine dioxide.

Chlorine dioxide obtained from the above mentioned process is measured by HACH Colorimeter DR890 approved by USEPA (United States Environment Protection Agency) by DPD 4500 method.

The stability of the liquid chlorine dioxide depend primarily upon the concentration of two components Sodium Salt Textone & Sodium Peroxydisulphate or Sodium Hydrogen Sulphate and concentration of water in the mixture and also the temperature to which the mixture is exposed. Each component has shelf life of more than 2 years.

It also represents a departure from all other systems in that the chlorine dioxide produced is in liquid form, 99% pure, and free of any harmful byproducts such as MX(Mutagen X), THM(Tri Halo Methanes), HAA(Halo Acetic Acids), Alkali metal sulfates, Chlorites, Chlorates, free Chlorine, Chloramines etc. Production yield of the chorine dioxide is >99%.

Liquid solution of chlorine dioxide retains its strength or remains stable for longer periods of time if kept cool and properly stored in the dark. Also, in a watery solution chlorine dioxide remain stable and soluble.

Chlorine dioxide prepared from the above preparation method is easy to handle and store and also has higher solubility in water. The shelf life of liquid chlorine dioxide obtained as per kinetic half time is >30 days. Preparing chlorine dioxide following the foregoing process does not require highly technical assistance.

Moreover, this process of producing stable liquid chlorine dioxide is absolutely free of any reducing agents and also does not involve any generator or instruments for the production of the same. The process to producing chlorine dioxide can be operated at any place without any explosion hazards.

Preparation method for liquid chlorine dioxide does not require generator, hence the process is free of any maintenance cost.

Liquid chlorine dioxide obtained from the above process is non hazardous, has disinfectant property with no side effects on its application in various fields. It is very effective potent biocide, steady bactericidal & virucidal activity and shows efficacy action within pH level between 4.0 to 10.0. Liquid chorine dioxide obtained by the above process is highly efficient in removal of iron and manganese and cyanide compounds from water. Liquid Chlorine dioxide obtained by the foregoing process has many applications. It is used in the electronics industry to clean circuit boards, in the oil industry to treat sulfides and to bleach textile and candles. Chlorine dioxide has the advantage that it produces less harmful byproducts than chlorine. Liquid Chlorine dioxide can be used as oxidizer or disinfectant and pesticide; it is a very strong oxidizer and it effectively kills pathogenic microorganisms such as fungi, bacteria and viruses; it also prevents and removes algae and bio film and scale as well.

Liquid chlorine dioxide obtained from the above process is effective water purifier, which eliminates organic contaminants and carcinogenic substances present in water. Organic contaminants falls within the group such as viruses, bacteria, giardia, botulism Cryptosporidium, E coli, cholera, fungi and sediments. Carcinogenic substances fall within a group of pollutants in waste water, cyanides in waste water, nitrites and sulfides, 3,4-benzopyrene, iron and manganese in water, tastes and odors produced by algae, dyes produced from chlorophyl and plants, pesticides.

Chorine dioxide does not react with ammonia, nitrogenous compounds precursors to form chloroform as chlorine does. It does not produce THMs and also does not form chloroform and bromochloromethane. It is an antimicrobial, antiviral, antibacterial liquid helps immune system to effectively treat cancer, malaria, hepatitis, leukemia, asthma, flu, arthritis, HIV and H1 N1 flu.

This invention will be better understood by referring to the following specific examples, but it is not intended to limit the scope of the invention.

Examples:

Example 1 Preparation of pure Liquid chlorine dioxide of 4500 ppm (0.45%): (A) Preparation of liquid solution of Sodium Salt Textone (Sodium chlorite):

8 part of liquid sodium salt textone (sodium chlorite) and 2 part potable drinking water are mixed properly in pure stainless steel vessel or glass or HDPE or PP vessels. The mixture is stirred at least 15 minutes for complete mixing.

80% NaCI0₂ + 20% H₂0 = 100% Sodium Salt Textone super concentrated liquid

2 part of Sodium peroxydisulphate in crystal or powder form and 8 part of potable drinking water are mixed properly in glass vessels or fiber glass or HDPE or PP vessels. The mixture is stirred at least 25 minutes to dissolve solid particles. When dissolved Sodium peroxydisulphate would be about 75% to 85%, add remaining 15% to 25% potable drinking water for complete mixing.

20% Na₂S₂0₈ + 80% H₂0 = 75% to 85% Na₂S₂0₈ then added 15% to 25% H₂0 = 100% Sodium peroxydisulphate super concentrated liquid

(C) Preparation of liquid chorine dioxide using liquid solution of A & liquid solution B:

Container of HDPE / glass / fiber glass quality is filled with 90% of potable water. 5% of liquid solution obtained in step A is added into water, 5% of liquid solution obtained in step B is also added into water. Now container is closed properly and kept for at least 3-5 hours in dark place at room temperature to complete reaction. Liquid chlorine dioxide obtained is >99% pure and stable.

Example 2 Preparation of pure Liquid chlorine dioxide of 4900 ppm (0.49%):

Liquid solution of liquid sodium salt textone (sodium chlorite) & sodium peroxydisulphate were prepared as explained in example 1.

Preparation of chlorine dioxide comprised the following procedural steps:

1 ) HDPE / glass / fiber glass quality was filled with 92.5 % of potable drinking water,

2) Then 5% liquid solution of sodium salt textone is added into water, 3) Then 2.5 % liquid solution Na₂S₂0₈ is added into water,

4) Container is closed and kept for at least 3 to 5 hours in dark place at room temperature to Complete Reaction to generate stable & pure CI0₂ liquid,

5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable.

Example 3 Preparation of pure Liquid chlorine dioxide of 7600 ppm (0.76%):

Liquid solution of liquid sodium salt textone (sodium chlorite) & sodium peroxydisulphate were prepared as explained in example 1 .

1 ) HDPE / glass / fiber glass quality was filled with 90 % of potable drinking water,

2) Then 5% liquid solution of sodium salt textone is added into water,

3) Then 5 % liquid solution Na₂S₂0₈ is added into water,

4) Container is closed and kept for at least 5 to 7 hours in dark place at room temperature to Complete Reaction to generate stable & pure CI0₂ liquid,

5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable.

Example 4 Preparation of pure Liquid chlorine dioxide of 50000 ppm (5.0%):

1 ) HDPE / glass / fiber glass quality was filled with 50 % of potable drinking water,

2) Then 25% liquid solution of sodium salt textone is added into water,

3) Then 25 % liquid solution Na₂S₂0e is added into water,

5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable. Example 5 Preparation of pure Liquid chorine dioxide 4900 ppm (0.49%) using NaHS0₄:

(A) Preparation of liquid solution of Sodium Salt Textone (Sodium chlorite): 8 part of liquid sodium salt textone (sodium chlorite) and 2 part potable drinking water are mixed properly in pure stainless steel vessel or glass or HDPE or PP vessels. The mixture is stirred at least 15 minutes for complete mixing.

80% NaCI0₂ + 20% H₂0 = 100% Sodium Salt Textone super concentrated liquid

(B) Preparation of liquid solution of NaHS0₄

4 part of NaHS0₄ in crystal or powder form and 6 part of potable drinking water are mixed properly in glass vessels or fiber glass or HDPE or PP vessels. The mixture is stirred at least 25 minutes to dissolve solid particles.

When dissolved Sodium peroxydisulphate would be about 75% to 85%, add remaining 15% to 25% potable drinking water for complete mixing.

40% NaHS0₄ + 60% H₂0 = 70% to 85% NaHS0₄ then added 15% to 25% H₂0 = 100% NaHS0₄ super concentrated liquid

(C) Preparation of chlorine dioxide liquid using solution A & B:

2) Then 5% liquid solution of sodium salt textone is added into water,

3) Then 5 % liquid solution NaHS0₄ is added into water,

5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable.

Example 6 Preparation of pure liquid chorine dioxide 7600 ppm (0.76%) using NaHS0₄:

Liquid solution A & B were prepared as explained in example 5. Preparation of chlorine dioxide using solution A & B comprised the following steps.

1 ) HDPE / glass / fiber glass quality was filled with 85 % of potable drinking water, 2) Then 5% liquid solution of sodium salt textone is added into water,

3) Then 10 % liquid solution NaHS0₄ is added into water,

4) Container is closed and kept for at least 5 to 7 hours in dark place at room temperature to complete Reaction to generate stable & pure CIO2 liquid, 5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable.

Example 7 Preparation of pure liquid chorine dioxide 25000 ppm (2.5%) using NaHS0₄:

1 ) HDPE / glass / fiber glass quality was filled with 55 % of potable drinking water,

2) Then 15% liquid solution of sodium salt textone is added into water,

3) Then 30 % liquid solution NaHS0₄ is added into water,

4) Container is closed and kept for at least 5 to 7 hours in dark place at room temperature to complete Reaction to generate stable & pure CIO₂ liquid,

5) Stirred the mixture gently,

6) chlorine dioxide obtained is >99% pure and stable.

For preparation of stable & pure liquid form of chlorine dioxide, concentration of water addition is very important. Any change in the percentage of water addition can prepare different ppm strength Level of CIO₂.

Claims

Claim:

A process of producing stable and pure liquid chlorine dioxide comprises two components system in liquid solution, wherein the system is formed by Sodium Salt Textone (Sodium Chlorite, NaCIO₂) and Sodium Peroxydisulphate (Sodium Persulphate, Na₂S₂O₈) or Sodium Hydrogen Sulphate (Sodium bisulphate,NaHSO₄) component.

A process of producing liquid chlorine dioxide as claimed in claim 1 comprising the steps of:

(a) preparing liquid solution of Sodium Salt Textone by using 8 part of sodium salt textone liquid and 2 part potable drinking water, mixing in pure stainless steel vessel or glass or HDPE (High density polyethylene) or PP (Polypropylene) vessels, stirring for at least 15 minutes;

(b) preparing liquid solution of Sodium Peroxydisulphate by using 4 part of Sodium peroxydisulphate crystal/powder and 6 part of potable drinking water, mixing in glass vessel or fiber glass or HDPE or PP vessel, stirring for at least 25 minutes to dissolve solid particles, further adding remaining 25% to 30% potable drinking water for complete mixing;

Or

preparing liquid solution of Sodium Hydrogen Sulphate by using 4 part of Sodium Hydrogen Sulphate crystal/powder and 6 part of potable drinking water, mixing in glass vessel or fiber glass or HDPE or PP vessel, stirring for at least 25 minutes to dissolve solid particles, further adding remaining 25% to 30% potable drinking water for complete mixing;

(c) preparing liquid chorine dioxide using liquid solution obtained from step (a) &(b),wherein, filling HDPE / glass / fiber glass quality container with 90% of potable water, adding 5% of liquid solution obtained in step a, further adding 5% of liquid solution obtained in step b, container is closed properly and kept or at least 3-5 hours in dark place at room temperature for complete reaction for generating stable and pure liquid chlorine dioxide.

3. A process as claimed in claim 1 & 2 wherein, sodium salt textone is used in liquid form of purity ranges between 25% - 32%.

4. A process as claimed in claim 3 wherein liquid sodium salt textone can be prepared using crystal/powder form (50% - 80% pure) of sodium salt textone and water.

5. A process of producing chlorine dioxide as claimed in claim 1 to 4 wherein, liquid chlorine dioxide is generated between 500 ppm (0.05%) to 50000 ppm (5.0%) is highly stable form. 6. A process of producing liquid chlorine dioxide as claimed in claim 5 wherein, chlorine dioxide obtained is >99% pure.

7. A process of producing liquid chlorine dioxide as claimed in claim 5 & 6 wherein, pure liquid chlorine dioxide obtained is free from any harmful by products such as MX(Mutagen X), THM(Tri Halo Methanes), HAA(Halo Acetic Acids), Alkali metal sulfates, Chlorites, Chlorates, Free Chlorine, Chloramines, etc.

8. A process of producing liquid chlorine dioxide as claimed in claims 1 to 7 wherein, the process is absolutely free of using reducing agents.

9. A process as claimed in claim 1 to 8 wherein, in the preparation of liquid chlorine dioxide water is used, any change in the concentration and or percentage of water addition causing different ppm strength level of chlorine dioxide production. 10. A process as claimed in claim 8; wherein liquid chlorine dioxide can be prepared without using any generator at any site and also reduces the chances of any explosion hazards.

11. A process as claimed in claim 1 to 10 wherein, Sodium peroxydisulphate (Sodium Persulphate, Na₂S₂0₈) or Sodium Hydrogen Sulphate (Sodium Bisulphate,NaHS0₄) is an activator for reaction with Sodium Salt Textone (Sodium Chlorite, NaCI0₂) to generate stable & pure liquid chlorine dioxide.

12. A process of producing stable and pure liquid chlorine dioxide as claimed in claims 1 to 1 are herein described and accompanied with foregoing description and examples.