Title of Invention	"A PROCESS FOR THE PREPARATION OF AQUEOUS SOLUBLE POLYANILINES BY MICROEMULSION TECHNIQUE"
Abstract	9. This invention relates to a process for the preparation of soluble polyanilines by microemulsion technique in its conducting from. The polyanilines prepared by the process of this invention is in its conducting form, known as the emeraldine salt form. The emeraldine salt form of polyanilines are usually insoluble in aqueous and most of the common organic solvents.The process steps comprises; polymerising of aniline or substituted anilines in an organic solvent as herein described in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.

Title of Invention

"A PROCESS FOR THE PREPARATION OF AQUEOUS SOLUBLE POLYANILINES BY MICROEMULSION TECHNIQUE"

Abstract

9. This invention relates to a process for the preparation of soluble polyanilines by microemulsion technique in its conducting from. The polyanilines prepared by the process of this invention is in its conducting form, known as the emeraldine salt form. The emeraldine salt form of polyanilines are usually insoluble in aqueous and most of the common organic solvents.The process steps comprises; polymerising of aniline or substituted anilines in an organic solvent as herein described in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.

Full Text	This invention relates to a process for the preparation of soluble polyanilmes by microemulsion technique. More particularly it relates to a process for the preparation of aqueous soluble polyanilmes by microemulsion technique in its conducting form. The polyanilmes prepared by the process of this inventin is in its conducting form, known as the emeraldme salt form. The emeraldine salt form of polyanilmes are usually insoluble in aqueous and most of the common organic solvents. Polyanilmes can be defined as materials composed of structural repeating units formed by two aniline molecules. These units can be either in reduced(amine) state or in an oxidised(imine) form. The most important type of polyaniline is emeraldine in which the participation of both reduced and oxidised states are equal. The unprotonated polyaniline, called emeraldine base is an electric insulator. The electric conductivity observed in polyaniline is associated with the protonated form, called emeraldine salt [W.S. Huang, B.D. Humphrey and A.G. MacDiarmid, J. Chem. Soc., Faraday Trans., 1, 82, 2385 (1986); A.G. MacDiarmid, J.C. Chiang, A.F. Richter and A.J. Epsteom, Synth. Met., 18, 285, (1987); A. Roy, G.E. Asturias, D.L. Kershner, A.F. Richter and A.G. MacDiarmid, Synth. Met., 29, 141, (1989)]. Controlled oxidative polymerisation of aniline in the presence of acids yields polyaniline in its emeraldine salt form [Macromol., 26, 3254, (1993)]. Emeraldine salt form can be converted into emeraldine base by increasing the pH and can be reconverted by the same or different acid, to make it conductive [Yasuhisa Maeda, Ai Katsuta, Kunio Nagasaki and Masashi Kamiyama, J. Electrochem. Soc., 142, (1995), 2261, E. M. Genies and C. Tsintavis, J. Electroanal. Chem., 111, (1980), 111]. It is known that polyanilines, especially in the emeraldine salt form, are insoluble in aqueous solvents and most common organic solvents. It is intractable and very difficult to process [E.M. Genies, A. Boyle, M. Lapkowski and C. Tsintavis, Synth. Met., 36 (1990), 139] . The polyaniline family of compounds is considered as most attractive polymer material, due to their environmental stability, their well-behaved electrochemistry, electrochromism, moderately high conductivity on doping, low cost of raw materials and ease of synthesis. It can exist in several molecular forms, differing in chemical composition, structure and electrical conductivity. All these forms can be interconverted into each other by chemical or electrochemical oxidation [T. Kabayashi, H. Yoneyama and H. Tamura, J. Electronal. Chem., 161, (1984), 419]. The synthesis of soluble polyaniline is of great interest since the formation of a soluble material is essential in order to facilitate post-synthesis processing. There are three possible methods for improving the processibility of polyaniline polymers : (1)- Formation of the polymer salt using an acid functionalised by a large non-polar substituent (counterion induced processibility), (2) Prefunctionalisation of the starting monomer with a suitable group prior to polymerisation and (3) Preparation of polyaniline dispersions. However the Polyaniline dispersions reported so far precipite rapidly. The present invention provides a process to overcome the drawback of insolubility of polyaniline, in its conducting form, namely the emeraldine salt, in aqueous systems. The object of the present invention therefore is to provide a process for the preparation of aqueous soluble polyaniline using microemulsion technique. Another object of the invention is to provide a process wherein the synthesised soluble emeraldine salt is a very clear green solution which can be diluted to any extent. Yet another object of the invention is to provide a process for the preparation of soluble polyaniline with increased storage stability. Accordingly, the present invention provides a process for the preparation of aqueous soluble polyanilines by microemulsion technique which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product. In an embodiment of the present invention, the substituted anilines used may be chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline. In yet another embodiment of the invention, the organic solvent used to prepare the solution of aniline or substituted aniline may be selected from xylene, ethyl benzene and toluene and the like. In still another embodiment, the acid used is selected from mineral acids like hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid, sulphonic acids like toluene sulphonic acid, methane sulphonic acid and the like. In yet another embodiment, the oxidising agent used may be selected from hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium bromate, potassium iodate, sodium iodate, potassium dichromate, potassium permanganate, peracids and the like. In another embodiment of invention, the surfactant used may be selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide and the like. In another embodiment, the cosurfactant may be selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol and the like. The process of the present invention is described with reference to following examples which are illustrative only and should not be construed to limit the scope of this invention, in any manner. Example 1 : 5 ml of 1 molar solution of aniline in toluene was poured into a mixture of 50 ml of 2% solution of cetyl pyridinium chloride and 5 ml of pentanol and mixed thoroughly. To this system were added 5 ml of concentrated hydrochloric acid and 2.2 g of potassium dichromate dissolved in 25 ml of water. The reaction was allowed o to proceed at 5 C in an ice bath for 2 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 95 grams. Example 2 : 3 ml of 2 molar solution of aniline in ethyl benzene was poured into a mixture of 75 ml of 4% solution of cetyl trimethyl ammonium bromide and 10 ml of n-hexanol and mixed thoroughly. To this system were added 3 ml of concentrated nitric acid and 2.07 g potassium permanganate dissolved in 25 ml of water. The o reaction was allowed to proceed at 10 C in an ice bath for 24 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 12 7 grams. Example 3 : 3 ml of 3 molar solution of aniline in xylene was poured into a mixture of 100 ml of 6% solution of benzene trimethyl ammonium chloride and 15 ml of cyclohexanol and mixed thoroughly. To this system were added 4 g of toluene sulphonic acid and 2.7 g of sodium iodate dissolved in 25 ml of water. The reaction was o allowed to proceed at 10 C in an ice bath for 12 hours. Final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 160 grams. Example 4 : 3 ml of 2 molar solution of N-methyl aniline in toluene was poured into a mixture of 75 ml of 4% solution of cetyl pyridinium bromide and 10 ml of n-hexanol and mixed thoroughly. To this system were added 5 ml of concentrated phosphoric acid and 1.02 ml of 30% aqueous solution of hydrogen peroxide. The reaction was o allowed to proceed at 10 C in an ice bath for 4 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 13 0 grams. Example 5 : 6 ml of 1 molar solution of 2-bromo aniline in xylene was poured into a mixture of 75 ml of 3% solution of sodium dodecyl sulphate and 2 0 ml of hexanol and mixed thoroughly. To this system were added 4 ml of methane sulphonic acid and 1.98 g of ammonium persulphate dissolved in 25 ml of water. The reaction was allowed o to proceed at 15 C in an ice bath for 12 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 165 grams. Example 6 : 4 ml of 2 molar solution of N-ethylaniline in ethyl benzene was poured into a mixture of 100 ml of 5% solution of benzyl trimethyl ammonium bromide and 15 ml of isopropanol and mixed thoroughly. To this system were added 7.5 ml perchloric acid and 3.28 g potassium persulphate dissolved in 25 ml of water. The o reaction was allowed to proceed at 15 C in an ice bath for 6 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 160 grams. Example 7 : 5 ml of 1.5 molar solution of 2-methoxyaniline in xylene was poured into a mixture of 60 ml of 2% solution of cetyl trimethyl ammonium chloride and 8 ml of 2-hexanol and mixed thoroughly. To this system were added 4 ml of concentrated nitric acid and 2.4 g of potassium iodate dissolved in 25 ml of water. The reaction o was allowed to proceed at 20 C in a water bath for 4 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 108 grams. Example 8 : 2 ml of 3 molar solution of 2-methoxyaniline in toluene was poured into a mixture 75 ml of 4% solution of cetyl pyridinium chloride and 15 ml of heptanol and mixed thoroughly. To this system were added 6 ml of concentrated sulphuric acid and 1.5 g of potassium bromate dissolved in 25 ml of water. The reaction o was allowed to proceed at 20 C in a water bath for 5 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 132 grams. Example 9 : 2 ml of 3 molar solution of 2-methylaniline in toluene was poured into a mixture 50 ml of 2.5% solution of benzyl trimethyl ammonium chloride and 15 ml of propanol and mixed thoroughly. To this system were added 8 ml of hydrochloric acid and 2.64 g of potassium dichromate dissolved in 25 ml of water. The reaction o was allowed to proceed at 25 C for 7 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 106 grams. Example 10 : 3 ml of 4 molar solution of 2-ethoxyaniline in xylene was poured into a mixture 75 ml of 5% solution of cetyl trimethyl ammonium chloride and 5 ml of hexanol and mixed thoroughly. To this system were added 6 g of toluene sulphonic acid and 4.14 g of ammonium persulphate dissolved in 25 ml of water. The reaction was allowed o to proceed at 30 C in a water bath for 24 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 12 7 grams. Example 11 : 2.5 ml of 3 molar solution of 2-methoxy-6-methyl aniline in toluene was poured into a mixture 50 ml of 3% solution of sodium dodecyl sulphate and 10 ml of butanol and mixed thoroughly. To this system were added 6 ml of concentrated hydrochloric acid and 1.28 ml of 30% aqueous solution of hydrogen peroxide. The o reaction was allowed to proceed at 35 C in a water bath for 18 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 104 grams. Example 12 : 2 ml of 4 molar solution of 2-methoxy-6-methyl aniline in xylene was poured into a mixture 100 ml of 4% solution of cetyl puridinim chloride and 15 ml of 2-butanol and mixed thoroughly. To this system were added 7 ml of concentrated phosphoric acid and 2.64 g of potassium iodate dissolved in 25 ml of water. The o reaction was allowed at 40 C in a water bath for 4 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 158 grams. Example 13 : 3 ml of 2 molar solution of 2-ethyl aniline in ethyl benzene was poured into a mixture 50 ml of 2% solution of cetyl trimethyl ammonium bromide and 10 ml of pentanol and mixed thoroughly. To this system were added 8 ml concentrated sulphuric acid and 2.07 g of potassium permanganate dissolved in 25 ml of water. The o reaction was allowed to proceed at 45 C in a water bath for 24 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 102 grams. Example 14 : 2 ml of 4 molar solution of 2,6-dimethyl aniline in toluene was poured into a mixture of 75 ml of 4% solution of cetyl pyridinium bromide and 2 0 ml of cyclohexanol and mixed thoroughly. To this system were added 5 ml concentrated hydrochloric acid and 3.2 8 g potassium persulphate dissolved in 25 ml of water. The reaction o was allowed to proceed at 50 C in a water bath for 6 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 132 grams. Example 15 : 2 ml of 6 molar solution of 2,6-dimethyl aniline in toluene was poured into a mixture of 100 ml of 6% solution of benzene trimethyl ammonium bromide and 15 ml of 3-hexanol and mixed thoroughly. To this system were added 5 ml of concentrated nitric acid and 4.14 g of ammonium persulphate dissolved in 25 ml of o water. The reaction was carried out at 60 C in a water bath for 8 hours. The final product obtained was a clear green solution of soluble polyaniline in the emeraldine salt form. The yield obtained was 165 grams. The advantages offered by the process of the invention are : 1. The products obtained as per the process of this invention meet the requirement for the use as a soluble form of polyaniline. 2. The polyaniline solution can be diluted to any extent and is stable for a long period of time. 3. The polyanilines prepared have very fine, well defined structure. 4. The polyanilines prepared can be easily processed to films and other forms in aqueous system. 5. The dedoping and redoping processes can be done effectively. We Claim: 1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product. 2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline. 3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene. 4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid. 5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium bromate, potassium iodate, sodium iodate, potassium dichromate, potassium permanganate, peracids are used. 6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide. 7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol. 8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples. We Claim: 1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product. 2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline. 3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene. 4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid. 5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium bromate, potassium iodate, sodium iodate, potassium dichromate, potassium permanganate, peracids are used. 6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide. 7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol. 8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples. We Claim: 1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product. 2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline. 3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene. 4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid. 5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium bromate, potassium iodate, sodium iodate, potassium dichromate, potassium permanganate, peracids are used. 6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide. 7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol. 8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples.

Full Text

This invention relates to a process for the preparation of soluble polyanilmes by microemulsion technique. More particularly it relates to a process for the preparation of aqueous soluble polyanilmes by microemulsion technique in its conducting form. The polyanilmes prepared by the process of this inventin is in its conducting form, known as the emeraldme salt form. The emeraldine salt form of polyanilmes are usually insoluble in aqueous and most of the common organic solvents.
Polyanilmes can be defined as materials composed of structural repeating units formed by two aniline molecules. These units can be either in reduced(amine) state or in an oxidised(imine) form. The most important type of polyaniline is emeraldine in which the participation of both reduced and oxidised states are equal. The unprotonated polyaniline, called emeraldine base is an electric insulator. The electric conductivity observed in polyaniline is associated with the protonated form, called emeraldine salt [W.S. Huang, B.D. Humphrey and A.G. MacDiarmid, J. Chem. Soc., Faraday Trans., 1, 82, 2385 (1986); A.G. MacDiarmid, J.C. Chiang, A.F. Richter and A.J. Epsteom, Synth. Met., 18, 285, (1987); A. Roy, G.E. Asturias, D.L. Kershner, A.F. Richter and A.G. MacDiarmid, Synth. Met., 29, 141, (1989)].
Controlled oxidative polymerisation of aniline in the
presence of acids yields polyaniline in its emeraldine salt form
[Macromol., 26, 3254, (1993)]. Emeraldine salt form can be

converted into emeraldine base by increasing the pH and can be reconverted by the same or different acid, to make it conductive [Yasuhisa Maeda, Ai Katsuta, Kunio Nagasaki and Masashi Kamiyama, J. Electrochem. Soc., 142, (1995), 2261, E. M. Genies and C. Tsintavis, J. Electroanal. Chem., 111, (1980), 111]. It is known that polyanilines, especially in the emeraldine salt form, are insoluble in aqueous solvents and most common organic solvents. It is intractable and very difficult to process [E.M. Genies, A. Boyle, M. Lapkowski and C. Tsintavis, Synth. Met., 36 (1990), 139] .
The polyaniline family of compounds is considered as most attractive polymer material, due to their environmental stability, their well-behaved electrochemistry, electrochromism, moderately high conductivity on doping, low cost of raw materials and ease of synthesis. It can exist in several molecular forms, differing in chemical composition, structure and electrical conductivity. All these forms can be interconverted into each other by chemical or electrochemical oxidation [T. Kabayashi, H. Yoneyama and H. Tamura, J. Electronal. Chem., 161, (1984), 419].
The synthesis of soluble polyaniline is of great interest since the formation of a soluble material is essential in order to facilitate post-synthesis processing.
There are three possible methods for improving the processibility of polyaniline polymers :

(1)- Formation of the polymer salt using an acid functionalised by a large non-polar substituent (counterion induced processibility),
(2) Prefunctionalisation of the starting monomer with a suitable group prior to polymerisation and
(3) Preparation of polyaniline dispersions. However the Polyaniline dispersions reported so far precipite rapidly.
The present invention provides a process to overcome the drawback of insolubility of polyaniline, in its conducting form, namely the emeraldine salt, in aqueous systems.
The object of the present invention therefore is to provide a process for the preparation of aqueous soluble polyaniline using microemulsion technique.
Another object of the invention is to provide a process wherein the synthesised soluble emeraldine salt is a very clear green solution which can be diluted to any extent.
Yet another object of the invention is to provide a process for the preparation of soluble polyaniline with increased storage stability.
Accordingly, the present invention provides a process for the preparation of aqueous soluble polyanilines by microemulsion technique which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or

sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.
In an embodiment of the present invention, the substituted anilines used may be chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline.
In yet another embodiment of the invention, the organic solvent used to prepare the solution of aniline or substituted aniline may be selected from xylene, ethyl benzene and toluene and the like.
In still another embodiment, the acid used is selected from mineral acids like hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid, sulphonic acids like toluene sulphonic acid, methane sulphonic acid and the like.
In yet another embodiment, the oxidising agent used may be selected from hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium bromate, potassium iodate, sodium iodate, potassium dichromate, potassium permanganate, peracids and the like.

In another embodiment of invention, the surfactant used may be selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide and the like.
In another embodiment, the cosurfactant may be selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol and the like.
The process of the present invention is described with reference to following examples which are illustrative only and should not be construed to limit the scope of this invention, in any manner.
Example 1 :
5 ml of 1 molar solution of aniline in toluene was poured into a
mixture of 50 ml of 2% solution of cetyl pyridinium chloride and
5 ml of pentanol and mixed thoroughly. To this system were added
5 ml of concentrated hydrochloric acid and 2.2 g of potassium
dichromate dissolved in 25 ml of water. The reaction was allowed
o to proceed at 5 C in an ice bath for 2 hours. The final product
obtained was a clear green solution of soluble polyaniline in the
emeraldine salt form. The yield obtained was 95 grams.

Example 2 :
3 ml of 2 molar solution of aniline in ethyl benzene was poured
into a mixture of 75 ml of 4% solution of cetyl trimethyl
ammonium bromide and 10 ml of n-hexanol and mixed thoroughly. To
this system were added 3 ml of concentrated nitric acid and 2.07
g potassium permanganate dissolved in 25 ml of water. The
o reaction was allowed to proceed at 10 C in an ice bath for 24
hours. The final product obtained was a clear green solution of
soluble polyaniline in the emeraldine salt form. The yield
obtained was 12 7 grams.
Example 3 :
3 ml of 3 molar solution of aniline in xylene was poured into a
mixture of 100 ml of 6% solution of benzene trimethyl ammonium
chloride and 15 ml of cyclohexanol and mixed thoroughly. To
this system were added 4 g of toluene sulphonic acid and 2.7 g of
sodium iodate dissolved in 25 ml of water. The reaction was
o allowed to proceed at 10 C in an ice bath for 12 hours. Final
product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
160 grams.
Example 4 : 3 ml of 2 molar solution of N-methyl aniline in toluene was poured into a mixture of 75 ml of 4% solution of cetyl pyridinium bromide and 10 ml of n-hexanol and mixed thoroughly. To this

system were added 5 ml of concentrated phosphoric acid and 1.02
ml of 30% aqueous solution of hydrogen peroxide. The reaction was
o allowed to proceed at 10 C in an ice bath for 4 hours. The final
product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
13 0 grams.
Example 5 :
6 ml of 1 molar solution of 2-bromo aniline in xylene was poured
into a mixture of 75 ml of 3% solution of sodium dodecyl sulphate
and 2 0 ml of hexanol and mixed thoroughly. To this system were
added 4 ml of methane sulphonic acid and 1.98 g of ammonium
persulphate dissolved in 25 ml of water. The reaction was allowed
o to proceed at 15 C in an ice bath for 12 hours. The final product
obtained was a clear green solution of soluble polyaniline in the
emeraldine salt form. The yield obtained was 165 grams.
Example 6 :
4 ml of 2 molar solution of N-ethylaniline in ethyl benzene was
poured into a mixture of 100 ml of 5% solution of benzyl
trimethyl ammonium bromide and 15 ml of isopropanol and mixed
thoroughly. To this system were added 7.5 ml perchloric acid and
3.28 g potassium persulphate dissolved in 25 ml of water. The
o reaction was allowed to proceed at 15 C in an ice bath for 6
hours. The final product obtained was a clear green solution of
soluble polyaniline in the emeraldine salt form. The yield

obtained was 160 grams.
Example 7 :
5 ml of 1.5 molar solution of 2-methoxyaniline in xylene was
poured into a mixture of 60 ml of 2% solution of cetyl trimethyl
ammonium chloride and 8 ml of 2-hexanol and mixed thoroughly. To
this system were added 4 ml of concentrated nitric acid and 2.4 g
of potassium iodate dissolved in 25 ml of water. The reaction
o was allowed to proceed at 20 C in a water bath for 4 hours. The
final product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
108 grams.
Example 8 :
2 ml of 3 molar solution of 2-methoxyaniline in toluene was
poured into a mixture 75 ml of 4% solution of cetyl pyridinium
chloride and 15 ml of heptanol and mixed thoroughly. To this
system were added 6 ml of concentrated sulphuric acid and 1.5 g
of potassium bromate dissolved in 25 ml of water. The reaction
o was allowed to proceed at 20 C in a water bath for 5 hours. The
final product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
132 grams.
Example 9 :
2 ml of 3 molar solution of 2-methylaniline in toluene was poured into a mixture 50 ml of 2.5% solution of benzyl trimethyl

ammonium chloride and 15 ml of propanol and mixed thoroughly. To
this system were added 8 ml of hydrochloric acid and 2.64 g of
potassium dichromate dissolved in 25 ml of water. The reaction
o was allowed to proceed at 25 C for 7 hours. The final product
obtained was a clear green solution of soluble polyaniline in the
emeraldine salt form. The yield obtained was 106 grams.
Example 10 :
3 ml of 4 molar solution of 2-ethoxyaniline in xylene was poured
into a mixture 75 ml of 5% solution of cetyl trimethyl ammonium
chloride and 5 ml of hexanol and mixed thoroughly. To this system
were added 6 g of toluene sulphonic acid and 4.14 g of ammonium
persulphate dissolved in 25 ml of water. The reaction was allowed
o to proceed at 30 C in a water bath for 24 hours. The final
product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
12 7 grams.
Example 11 :
2.5 ml of 3 molar solution of 2-methoxy-6-methyl aniline in
toluene was poured into a mixture 50 ml of 3% solution of sodium
dodecyl sulphate and 10 ml of butanol and mixed thoroughly. To
this system were added 6 ml of concentrated hydrochloric acid and
1.28 ml of 30% aqueous solution of hydrogen peroxide. The
o reaction was allowed to proceed at 35 C in a water bath for 18
hours. The final product obtained was a clear green solution of
soluble polyaniline in the emeraldine salt form. The yield

obtained was 104 grams.
Example 12 :
2 ml of 4 molar solution of 2-methoxy-6-methyl aniline in xylene
was poured into a mixture 100 ml of 4% solution of cetyl
puridinim chloride and 15 ml of 2-butanol and mixed thoroughly.
To this system were added 7 ml of concentrated phosphoric acid
and 2.64 g of potassium iodate dissolved in 25 ml of water. The
o reaction was allowed at 40 C in a water bath for 4 hours. The
final product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
158 grams.
Example 13 :
3 ml of 2 molar solution of 2-ethyl aniline in ethyl benzene was
poured into a mixture 50 ml of 2% solution of cetyl trimethyl
ammonium bromide and 10 ml of pentanol and mixed thoroughly. To
this system were added 8 ml concentrated sulphuric acid and 2.07
g of potassium permanganate dissolved in 25 ml of water. The
o reaction was allowed to proceed at 45 C in a water bath for 24
hours. The final product obtained was a clear green solution of
soluble polyaniline in the emeraldine salt form. The yield
obtained was 102 grams.
Example 14 : 2 ml of 4 molar solution of 2,6-dimethyl aniline in toluene was poured into a mixture of 75 ml of 4% solution of cetyl pyridinium

bromide and 2 0 ml of cyclohexanol and mixed thoroughly. To this
system were added 5 ml concentrated hydrochloric acid and 3.2 8 g
potassium persulphate dissolved in 25 ml of water. The reaction
o was allowed to proceed at 50 C in a water bath for 6 hours. The
final product obtained was a clear green solution of soluble
polyaniline in the emeraldine salt form. The yield obtained was
132 grams.
Example 15 :
2 ml of 6 molar solution of 2,6-dimethyl aniline in toluene was
poured into a mixture of 100 ml of 6% solution of benzene
trimethyl ammonium bromide and 15 ml of 3-hexanol and mixed
thoroughly. To this system were added 5 ml of concentrated nitric
acid and 4.14 g of ammonium persulphate dissolved in 25 ml of
o water. The reaction was carried out at 60 C in a water bath for
8 hours. The final product obtained was a clear green solution of
soluble polyaniline in the emeraldine salt form. The yield
obtained was 165 grams.
The advantages offered by the process of the invention are :
1. The products obtained as per the process of this invention meet the requirement for the use as a soluble form of polyaniline.
2. The polyaniline solution can be diluted to any extent and is stable for a long period of time.

3. The polyanilines prepared have very fine, well defined structure.
4. The polyanilines prepared can be easily processed to films and other forms in aqueous system.
5. The dedoping and redoping processes can be done effectively.

We Claim:
1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.
2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline.
3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene.
4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid.
5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as
hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium
bromate, potassium iodate, sodium iodate, potassium dichromate, potassium
permanganate, peracids are used.
6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide.
7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol.

8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples.

We Claim:
1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.
2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline.
3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene.
4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid.
5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as
hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium
bromate, potassium iodate, sodium iodate, potassium dichromate, potassium
permanganate, peracids are used.
6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide.
7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol.

8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples.

We Claim:
1. A process for the preparation of aqueous soluble polyanilines by microemulsion technique, which comprises; polymerising of aniline or substituted anilines in an organic solvent in presence of mineral acid or sulphonic acid, and conventional oxidising agent as herein described at a temperature in the range of 0 to 60°C, in the presence of conventional surfactant and/or a co surfactant as herein described for a period ranging from 2 to 24 hours to obtain the product.
2. A process as claimed in claim 1, wherein, the substituted anilines used are chosen from N-methyl aniline, N-ethyl aniline, 2-bromoaniline, 2-methyl aniline, 2,6-dimethyl aniline, 6-methyl aniline, 2-methoxy aniline, 2-ethoxy aniline, 2-methoxy-6-methyl aniline.
3. A process as claimed in claims 1 and 2, wherein, the organic solvent used to prepare the solution of aniline or substituted aniline solution is selected from xylene, ethyl benzene and toluene.
4. A process as claimed in claims 1 to 3, wherein, the mineral acid used is selected from hydrochloric acid, sulphuric acid, perchloric acid, phosphoric acid, nitric acid & sulphonic acid such as toluene sulphonic acid, methane sulphonic acid.
5. A process as claimed in claims 1 to 4, wherein, the oxidising agent such as
hydrogen peroxide, ammonium persulphate, potassium persulphate, potassium
bromate, potassium iodate, sodium iodate, potassium dichromate, potassium
permanganate, peracids are used.
6. A process as claimed in claims 1 to 5, wherein, the surfactant used is selected from cetyl pyridinium chloride, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, sodium dodecyl sulphate, benzyl trimethyl ammonium chloride, benzyl trimethyl ammonium bromide.
7. A process as claimed in claims 1 to 6, wherein, the co-surfactant is selected from propanol, isopropanol, butanol, 2-butanol, pentanol, hexanol, 2-hexanol, 3-hexanol, cyclohexanol, heptanol.

8. A process for the preparation of aqueous soluble polyatiilines by microemulsion technique substantially as described herein with reference to the examples.

Documents:

3354-del-1997-abstract.pdf

3354-del-1997-claims.pdf

3354-del-1997-complete specification (granted).pdf

3354-del-1997-correspondence-others.pdf

3354-del-1997-correspondence-po.pdf

3354-del-1997-description (complete).pdf

3354-del-1997-form-1.pdf

3354-del-1997-form-19.pdf

3354-del-1997-form-2.pdf

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Patent Number

232775

Indian Patent Application Number

3354/DEL/1997

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

21-Mar-2009

Date of Filing

21-Nov-1997

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	MADATHIL RETHI	NATIONAL CHEMICAL LABORATORY , PUNE 411 008, MAHARASHTRA, INDIA.
2	CHELANATTU KHIZHAKKE MADATH RAMAN RAJAN	NATIONAL CHEMICAL LABORATORY , PUNE 411 008, MAHARASHTRA, INDIA
3	SURENDRA PONARATHNAM	NATIONAL CHEMICAL LABORATORY , PUNE 411 008, MAHARASHTRA, INDIA

PCT International Classification Number

C08G 73/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA