Indian Patents. 205278:"A PROCESS FOR THE PREPARATION OF THE ISOLABLE AND STORAGE STABLE TETRABUTYLAMMONIUM TRIBROMIDE(TBATB) FROM TETRABUTYLAMMONIUM BROMIDE(TBATB)"

Title of Invention	"A PROCESS FOR THE PREPARATION OF THE ISOLABLE AND STORAGE STABLE TETRABUTYLAMMONIUM TRIBROMIDE(TBATB) FROM TETRABUTYLAMMONIUM BROMIDE(TBATB)"
Abstract	There is disclosed a process for the preparation of the isolable and storage stable tetrabutylammonium tribromide , (TBATB), from tetrabutylammonium bromide (TBAB), which comprises subjecting TBAB to oxidation in the presence of a catalyst, an oxidizing agent and an alkali bromide under mild acidic condition at a temperature below room temperature followed by recovery of the product and drying.

Full Text	1. INTRODUCTION TO THE FIELD OF INVENTION This invention addresses a novel process for the preparation of a halogenating agent for organic compounds. This invention more particularly relates to a process for the preparation of tetrabutylammonium tribromide. TBATB. 2. PRIOR ARTS AND DRAWBACKS Several reagents are known for halogenating organic compounds in the art and processes for their preparation were also suggested. Patents on halogenation of organic compounds and for preparation of halogenated organic compounds have been granted. One such halogenating agent is TBATB. None of the prior arts has described an easily and* safely accessible route to TBATB and the reagent is therefore not very readily available for bromination of organic compounds. However, in a US Patent 5, 149, 875 there is disclosed a process for the preparation of halogenated fluoroaniline such as 2-bromo-4-fluoroanilinc. which is prepared from 4-fluoroaniline. In this process the fluoroaniline is subjected to bromination using in situ generated brominating agent, for example, TBATB. In this method the TBATB is generated from tetrabutylammonium bromide, TBAB, using a chemical process. Such a process involves molecular bromine and an organic medium namely methylene chloride for conducting the reaction. The use of molecular bromine entails several environmental problems and free bromine remaining at the end of the reaction is detrimental not only to the reagent but also to the further reactions involving it. Thus, it is possible that the full benefit of the bromination reaction is not realised in this process through in situ generation of TBATB. It is expected that the presence of free bromine might effect the bromination of fluproanilines and hamper selectivity of the reactions as well. The afore mentioned US Patent recommends recycling of the in situ bromination of fluoroaniline. In spite of all these, the yield of the final product, eg., 'i-bromo-4-fluoroaniline. is not very encouraging. -2. The US Patent also uses a halogenated organic solvent, namely methylene chloride in the preparation of brominated haloanilines. Legislations are anticipated in several countries evolving stringent conditions for the use of halogenated solvents (c.f. methylene chloride) and such chemicals / solvents are likely to be phased out. Thus, the US Patent might not remain to be an useful process for the purpose in near future. 3. OBJECTS OF THE INVENTION Therefore an object of this invention, is to prepare an efficient brominating agent namely tetrabutylammonium tribromide, TBATB, in a storage stable state by a simple, safe and yet efficient process. Another object is to provide such a process that will use all indigenously available chemicals and will not involve any complicated techniques. Yet another object of this invention is to introduce such a process that will avoid environmental pollution. In other words, the process will be environmentally safe and friendly. A further object of is to provide such a process-that will afford TBATB in a very high yield. A still further object is to provide such a reagent that will afford brominated haloaniline in very high yield and purity. The other object of the process is to make available of a procedure for obtaining TBATB which is safe to operate, non hazardous and cost effective. . All these and the other objects of this invention will be more clear from the following sections: 4. STATEMENT OF THE INVENTION Thus according to the present invention there is provided a process for the preparation of isolable and storage stable tetrabutylammonium tribromide. TBATB. from tetrabutylammonium bromide, TBAB, which is based on subjecting TBAB to oxidation by an oxidising agent in the presence of an alkali metal bromide at a temperature below room temperature under mild acidic conditions followed by, isolation of the product from the reaction and finally drying. ¦ 3 The above reaction is carried out using alkali bromide as an additional source of bromide. Any alkali metal bromide or ammonium bromide is usable but potassium bromide is most preferred as it is cheap and easily available. The oxidation of bromide to tribromide is carried out using a combination of two reagents namely vanadium pentoxide (V2O5) and hydrogen peroxide (H2O2) with the principal oxidising agent being H2O2. The metal oxide, V2O5, acts as a catalyst. The reaction of H2O2 with V2O5 produces a peroxo-vanadium(V) intermediate, thereby activating O:"". Peroxo-vanadium(V) species so generated is responsible for bringing about the oxidation of bromide (Br") to tribromide (Br3). It may be noted that another oxidant e.g. tert-butyl hydroperoxide or any other suitable alkyl hydroperoxide can as well be used for oxidation in combination with V2O5. Also important is to note that a salt of VO33' or any other appropriate vanadium(V) compound or an appropriate compound of molybdenum(VI) or tungstate(Vl) or tjtanium(IV) or copper(II) or iron(III) can be used as a catalyst in place of V2O5. The reaction is carried out by first preparing a water solution of a combination of the catalyst and oxidising agent followed by the addition to it, a temperature below room temperature, an aqueous solution of alkali bromide and TBAB. At the first stage, the requisite quantities of V2O5 and H2O2 solution are reacted at temperature below room temperature, and the clear aqueous solution is then kept at a temperature below room temperature. The solution of alkali bromide and TBAB is provided in water and is added to the water solution of the catalyst and the oxidising agent. The reaction medium is then maintained at a mild acidic pH using H2SO4 or HClO4 Sulphuric acid is preferred due to its relatively low cost and ready availability. 5. DETAILED DESCRIPTION OF THE INVENTION The invention will now be more fully described with reference to the following examples: Example 1 'An amount of 0.2 g (0.0011 mol) of V2O5 (s.d. fine-chem ltd) is added to 10 mL (0.0883 mol) of 30% H2O2 (Qualigens Fine Chemicals) taken in a pre-cooled 100 mL Borosil beaker (care sliould be taken to maintain ice-cold conditions as the reaction between V2O5 and H2O2 is exothermic). The reaction mixture is stirred using magnetic 4 stirrer till all the V2O5 dissolves and the solution becomes reddish-brown. It is then diluted with 10 mL of water and filtered under suction using Borosil G-4 crucible. The clear solution is diluted with 90 mL of water and poured into a 500 mL Borosil beaker that is placed in an ice-water bath. To this is added a solution of 5.8 g (0.0487 mol) of, KBr (E. Merck India Limited) and 7g (0.0217 mo!) of tetra butyl ammonium bromide (TBAB) (Sisco Research Laboratories Pvt. Ltd.) dissolved in 35 mL of water. Next 50 mL of 1M H2SO4 (Qualigens Fine Chemicals) is added in small portions. Stirring is continued for 2h at ice temperature. The product formed is then filtered by suction filtration using 542 Whatman filter paper. The compound is dried in a vacuum desiccator using CaCh (E. Merck India Limited) as desiccant. Total Yield : 9.9 g ( 94.5 %) Example 2 An amount of 0.1 g (0.0005 mol) of V2O5 (s.d. fme.-chem ltd) is added to 5 mL (0.04415 mol) of 30% H2O2 (Qualigens Fine Chemicajs) taken in a pre-cooled 100 mL Borosil beaker (care should be taken to maintain ice-cold conditions as the reaction between V2O5 and H2O2 is exothermic). The.reaction mixture is stirred using magnetic stirrer till all the V2O5 dissolves and the solution becomes reddish-brown. It is* then diluted with 5 mL of water and filtered under suction using Borosil G-4 crucible. The clear solution is diluted with 45 mL of water and poured into a 250 mL Borosil beaker that is placed in an ice-water bath. To this is added a solution of 2.38 g (0.02435 mol) of NH4Br (E. Merck India Limited) and 3.5g (0.01085 mol) of tetrabutylammonium bromide (TBAB) (Sisco Research Laboratories Pvt. Ltd.) dissolved in 20 mL of water. Next 25 mL of 1M H2SO4 (Qualigens Fine Chemicals) is added in small portions.' Stirring is continued for 2h at ice temperature. The product formed is then filtered by suction filtration using 542 Whatman filter paper. The compound is dried in a vacuum desiccator using CaCl2 (E. Merck India Limited) as desiccant. Total Yield 5.08 g (97%) NOTE The procedures described at Examples 1 and 2 may be scaled, either up or down, if desired. The preparations may be carried out also with other alkali bromides in place of KBr or NH4Br. 5 6. DETAILS OF THE COMPOUND PREPARED The compound prepared was subjected to analysis and the following observations were made. , The compound obtained by the method is micro crystalline in nature and very pure. Melting point : 77-78°C I-R v max (nujal) cm-1 : 1483, 1461, 1451, 1371, 1183,1148, 1105, 1051, 1025,877,804,740 U.V ?max(CH3;CN). nm : 267, 380 S11(CDCl3) : 1.05(12H, t, J = 7.3H2,-CH2-CH3), 1.50 (8H,m, -CH2-CH3), 1.72 (8H, m, -CH2-CH2-CH3), 3.32 (8H, m. N-CH2CH2-CH2-CH3,)- Analytical data: The compound analysed correctly C16H36NBr3 Calc. C. 39.85; H, 7.54; N; 2.91; Br, 49.71. Found. C. 39.82; H, 7.48; N, 3.11; Br, 49.78. Recrystallisation: Should bigger crystals be required, the product obtained may be recrystallised from acetonitrile (CH3CN). Procedure: Tetrabutylammonium tribromide (10g) was dissolved in acetonitrile (15mL) by slight warming in a l00mL beaker. The clear solution was left at room temperature for 12 h. Orange crystals were collected by filtration and dried on a filter paper. Yield: 9.7g (97%). The orange-red mother liquor was dried and found to contain the desired product in micro crystalline form. Solubility: TBATB is insoluble in water but soluble in most organic solvents, such as, CH3CN. CH2Cl2. CHCl3. MeOH, EtOH,AcOH, THF, Dioxane, DMF, DMSO., Stability: Stable at room temperature for several months. 7. ADVANTAGES OF THE INVENTION The synthetic process invented by us has several advantages, compared to the existing methods of preparation of TBATB. Some of the advantages are mentioned below: The synthetic methodology is: 6 • Environmentally friendly and clean, • Efficient • Operationally simple • Cost effective • ; Very facile and • Catalyst (V2O5) and oxidant (H2O2) are environmentally acceptable, and the pruduct is • Storage stable • Pure • . Free from interfering chemicals. • Less losses and high recovery are»the additional advantages. 8. USES OF THE COMPOUND FOR WHICH A NOVEL PROCESS HAS BEEN INVENTED Tetrabutylammonium tribromide is an efficient brominating agent and works extremely well under mild reaction conditions. A variety of organic substrates can be easily, brominated by TBATB. A few examples are given below: • Aroma tics (including aniline, phenols) • Polycyclic hydrocarbons • Sensitive substrates (eg. imidazole) • Ally] alcohol • Alkenes • Alkyncs • Ketones • Unreactive ring ( e.g benzene) • ?,? unsaturated carbonyl compounds • Acetals • Chemoselective bromination of activated ring in the presence of olefinic double bond The reagent is used in the determination of multiple bonds, and can well be used for oxidation in non aqueous medium. 7 WE CLAIM 1. A process for the preparation of the isolable and storage stable tetrabutylammonium tribromide, (TBATB), from tetrabutylammonium tribromide, (TBATB), which comprises subjecting TBAB to oxidation in the presence of a catalyst, an oxidizing agent and an alkali bromide under mild acidic condition at a temperature below room temperature followed by recovery of the product and drying. 2. A process as claimed in claim 1 wherein the above mentioned reaction is carried out using an alkali bromide such as NH4Br or alkali metal bromides preferably KBr. 3. A process as claimed in claim 2 wherein the reagent preferred is KBr. 4. A process as claimed in claims 1 to 3 wherein the catalyst is selected from a suitable compound of Ti(IV), iron(lll), copper(ll), molybdenum(VI), tungsten(VI) or V2O5. 5. A process as claimed in claims 1 to 4 wherein the oxidising agent is selected from tert - butyl hydroperoxide or any other alkyl hydroperoxide or H2O2 as the oxidising agent. 6. A process as claimed in claims 1 to 5 wherein the oxidation of TBAB is carried out by using V2O5 as the catalyst and H2O2 as the oxidising agent and thereby producing a peroxo - vanadium (V) in the reaction which is responsible for actual oxidation. 7. A process as claimed in claims 4 to 6 wherein the oxidation is carried out by first preparing a water solution of the combination of a catalyst and an oxidizing agent followed by the addition to it, at a temperature below room temperature, an aqueous solution of an alkali bromide and TBAB. 8. A process as claimed in claim 7 wherein at the first stage requisite quantities of V2O5 and H2O2 are reacted at a temperature below room temperature. 9 9. A process as claimed in claim 7 wherein the solution of an alkali bromide and TBAB is provided in water which is added to an aqueous solution of the combination of a catalyst and an oxidizing agent and the reaction solution is maintained at a mild acidic pH attained by using H2SO4 or HCLO4 , preferably H2SO4. 10. A process for the preparation of isolable and storage stable tetrabutylammonium tribromide, (TBATB), from tetrabutylammonium bromide (TBAB) substantially as described herein with reference to accompanying examples. Dated this 19 th day of January, 2000. There is disclosed a process for the preparation of the isolable and storage stable tetrabutylammonium tribromide , (TBATB), from tetrabutylammonium bromide (TBAB), which comprises subjecting TBAB to oxidation in the presence of a catalyst, an oxidizing agent and an alkali bromide under mild acidic condition at a temperature below room temperature followed by recovery of the product and drying.

Full Text

1. INTRODUCTION TO THE FIELD OF INVENTION
This invention addresses a novel process for the preparation of a halogenating agent for organic compounds.
This invention more particularly relates to a process for the preparation of tetrabutylammonium tribromide. TBATB.
2. PRIOR ARTS AND DRAWBACKS
Several reagents are known for halogenating organic compounds in the art and processes for their preparation were also suggested. Patents on halogenation of organic compounds and for preparation of halogenated organic compounds have been granted.
One such halogenating agent is TBATB.
None of the prior arts has described an easily and* safely accessible route to TBATB and the reagent is therefore not very readily available for bromination of organic compounds.
However, in a US Patent 5, 149, 875 there is disclosed a process for the preparation of halogenated fluoroaniline such as 2-bromo-4-fluoroanilinc. which is prepared from 4-fluoroaniline. In this process the fluoroaniline is subjected to bromination using in situ generated brominating agent, for example, TBATB.
In this method the TBATB is generated from tetrabutylammonium bromide, TBAB, using a chemical process. Such a process involves molecular bromine and an organic medium namely methylene chloride for conducting the reaction. The use of molecular bromine entails several environmental problems and free bromine remaining at the end of the reaction is detrimental not only to the reagent but also to the further reactions involving it. Thus, it is possible that the full benefit of the bromination reaction is not realised in this process through in situ generation of TBATB. It is expected that the presence of free bromine might effect the bromination of fluproanilines and hamper selectivity of the reactions as well.
The afore mentioned US Patent recommends recycling of the in situ bromination of fluoroaniline. In spite of all these, the yield of the final product, eg., 'i-bromo-4-fluoroaniline. is not very encouraging.
-2.

The US Patent also uses a halogenated organic solvent, namely methylene chloride in the preparation of brominated haloanilines. Legislations are anticipated in several countries evolving stringent conditions for the use of halogenated solvents (c.f. methylene chloride) and such chemicals / solvents are likely to be phased out. Thus, the US Patent might not remain to be an useful process for the purpose in near future.
3. OBJECTS OF THE INVENTION
Therefore an object of this invention, is to prepare an efficient brominating agent namely tetrabutylammonium tribromide, TBATB, in a storage stable state by a simple, safe and yet efficient process.
Another object is to provide such a process that will use all indigenously available chemicals and will not involve any complicated techniques.
Yet another object of this invention is to introduce such a process that will avoid environmental pollution. In other words, the process will be environmentally safe and friendly.
A further object of is to provide such a process-that will afford TBATB in a very high yield.
A still further object is to provide such a reagent that will afford brominated haloaniline in very high yield and purity.
The other object of the process is to make available of a procedure for obtaining TBATB which is safe to operate, non hazardous and cost effective. .
All these and the other objects of this invention will be more clear from the following sections:
4. STATEMENT OF THE INVENTION
Thus according to the present invention there is provided a process for the preparation of isolable and storage stable tetrabutylammonium tribromide. TBATB. from tetrabutylammonium bromide, TBAB, which is based on subjecting TBAB to oxidation by an oxidising agent in the presence of an alkali metal bromide at a temperature below room temperature under mild acidic conditions followed by, isolation of the product from the reaction and finally drying. ¦
3

The above reaction is carried out using alkali bromide as an additional source of bromide. Any alkali metal bromide or ammonium bromide is usable but potassium bromide is most preferred as it is cheap and easily available.
The oxidation of bromide to tribromide is carried out using a combination of two
reagents namely vanadium pentoxide (V2O5) and hydrogen peroxide (H2O2) with the
principal oxidising agent being H2O2. The metal oxide, V2O5, acts as a catalyst. The
reaction of H2O2 with V2O5 produces a peroxo-vanadium(V) intermediate, thereby
activating O:"". Peroxo-vanadium(V) species so generated is responsible for bringing
about the oxidation of bromide (Br") to tribromide (Br3). It may be noted that another
oxidant e.g. tert-butyl hydroperoxide or any other suitable alkyl hydroperoxide can as
well be used for oxidation in combination with V2O5. Also important is to note that a salt
of VO33' or any other appropriate vanadium(V) compound or an appropriate compound of
molybdenum(VI) or tungstate(Vl) or tjtanium(IV) or copper(II) or iron(III) can
be used as a catalyst in place of V2O5.
The reaction is carried out by first preparing a water solution of a combination of the catalyst and oxidising agent followed by the addition to it, a temperature below room temperature, an aqueous solution of alkali bromide and TBAB.
At the first stage, the requisite quantities of V2O5 and H2O2 solution are reacted at temperature below room temperature, and the clear aqueous solution is then kept at a temperature below room temperature. The solution of alkali bromide and TBAB is provided in water and is added to the water solution of the catalyst and the oxidising agent. The reaction medium is then maintained at a mild acidic pH using H2SO4 or HClO4 Sulphuric acid is preferred due to its relatively low cost and ready availability.
5. DETAILED DESCRIPTION OF THE INVENTION
The invention will now be more fully described with reference to the following examples: Example 1
'An amount of 0.2 g (0.0011 mol) of V2O5 (s.d. fine-chem ltd) is added to 10 mL (0.0883 mol) of 30% H2O2 (Qualigens Fine Chemicals) taken in a pre-cooled 100 mL Borosil beaker (care sliould be taken to maintain ice-cold conditions as the reaction between V2O5 and H2O2 is exothermic). The reaction mixture is stirred using magnetic
4

stirrer till all the V2O5 dissolves and the solution becomes reddish-brown. It is then diluted with 10 mL of water and filtered under suction using Borosil G-4 crucible. The clear solution is diluted with 90 mL of water and poured into a 500 mL Borosil beaker that is placed in an ice-water bath. To this is added a solution of 5.8 g (0.0487 mol) of, KBr (E. Merck India Limited) and 7g (0.0217 mo!) of tetra butyl ammonium bromide (TBAB) (Sisco Research Laboratories Pvt. Ltd.) dissolved in 35 mL of water. Next 50 mL of 1M H2SO4 (Qualigens Fine Chemicals) is added in small portions. Stirring is continued for 2h at ice temperature. The product formed is then filtered by suction filtration using 542 Whatman filter paper. The compound is dried in a vacuum desiccator using CaCh (E. Merck India Limited) as desiccant.
Total Yield : 9.9 g ( 94.5 %)
Example 2
An amount of 0.1 g (0.0005 mol) of V2O5 (s.d. fme.-chem ltd) is added to 5 mL
(0.04415 mol) of 30% H2O2 (Qualigens Fine Chemicajs) taken in a pre-cooled 100 mL
Borosil beaker (care should be taken to maintain ice-cold conditions as the reaction
between V2O5 and H2O2 is exothermic). The.reaction mixture is stirred using magnetic
stirrer till all the V2O5 dissolves and the solution becomes reddish-brown. It is* then
diluted with 5 mL of water and filtered under suction using Borosil G-4 crucible. The
clear solution is diluted with 45 mL of water and poured into a 250 mL Borosil beaker
that is placed in an ice-water bath. To this is added a solution of 2.38 g (0.02435 mol) of
NH4Br (E. Merck India Limited) and 3.5g (0.01085 mol) of tetrabutylammonium
bromide (TBAB) (Sisco Research Laboratories Pvt. Ltd.) dissolved in 20 mL of water.
Next 25 mL of 1M H2SO4 (Qualigens Fine Chemicals) is added in small portions.'
Stirring is continued for 2h at ice temperature. The product formed is then filtered by
suction filtration using 542 Whatman filter paper. The compound is dried in a vacuum
desiccator using CaCl2 (E. Merck India Limited) as desiccant.
Total Yield 5.08 g (97%)
NOTE
The procedures described at Examples 1 and 2 may be scaled, either up or down,
if desired. The preparations may be carried out also with other alkali bromides in place of KBr or NH4Br.
5

6. DETAILS OF THE COMPOUND PREPARED
The compound prepared was subjected to analysis and the following observations were made. ,
The compound obtained by the method is micro crystalline in nature and very

pure.
Melting point : 77-78°C
I-R v max (nujal) cm-1 : 1483, 1461, 1451, 1371, 1183,1148,
1105, 1051, 1025,877,804,740
U.V ?max(CH3;CN). nm : 267, 380
S11(CDCl3) : 1.05(12H, t, J = 7.3H2,-CH2-CH3), 1.50 (8H,m,
-CH2-CH3), 1.72 (8H, m, -CH2-CH2-CH3), 3.32 (8H, m.
N-CH2CH2-CH2-CH3,)-
Analytical data: The compound analysed correctly C16H36NBr3
Calc. C. 39.85; H, 7.54; N; 2.91; Br, 49.71.
Found. C. 39.82; H, 7.48; N, 3.11; Br, 49.78. Recrystallisation: Should bigger crystals be required, the product obtained may be recrystallised from acetonitrile (CH3CN).
Procedure: Tetrabutylammonium tribromide (10g) was dissolved in acetonitrile (15mL) by slight warming in a l00mL beaker. The clear solution was left at room temperature for 12 h. Orange crystals were collected by filtration and dried on a filter paper. Yield: 9.7g (97%). The orange-red mother liquor was dried and found to contain the desired product in micro crystalline form.
Solubility: TBATB is insoluble in water but soluble in most organic solvents, such as, CH3CN. CH2Cl2. CHCl3. MeOH, EtOH,AcOH, THF, Dioxane, DMF, DMSO., Stability: Stable at room temperature for several months.
7. ADVANTAGES OF THE INVENTION
The synthetic process invented by us has several advantages, compared to the existing methods of preparation of TBATB. Some of the advantages are mentioned below: The synthetic methodology is:
6

• Environmentally friendly and clean,
• Efficient
• Operationally simple
• Cost effective
• ; Very facile and

• Catalyst (V2O5) and oxidant (H2O2) are environmentally acceptable, and the pruduct is
• Storage stable
• Pure
• . Free from interfering chemicals.
• Less losses and high recovery are»the additional advantages.
8. USES OF THE COMPOUND FOR WHICH A NOVEL PROCESS HAS BEEN INVENTED
Tetrabutylammonium tribromide is an efficient brominating agent and works extremely well under mild reaction conditions. A variety of organic substrates can be easily, brominated by TBATB. A few examples are given below:
• Aroma tics (including aniline, phenols)
• Polycyclic hydrocarbons
• Sensitive substrates (eg. imidazole)
• Ally] alcohol
• Alkenes
• Alkyncs
• Ketones
• Unreactive ring ( e.g benzene)
• ?,? unsaturated carbonyl compounds
• Acetals
• Chemoselective bromination of activated ring in the presence of olefinic double bond The reagent is used in the determination of multiple bonds, and can well be used for
oxidation in non aqueous medium.
7

WE CLAIM
1. A process for the preparation of the isolable and storage stable tetrabutylammonium tribromide, (TBATB), from tetrabutylammonium tribromide, (TBATB), which comprises subjecting TBAB to oxidation in the presence of a catalyst, an oxidizing agent and an alkali bromide under mild acidic condition at a temperature below room temperature followed by recovery of the product and drying.
2. A process as claimed in claim 1 wherein the above mentioned reaction is carried out using an alkali bromide such as NH4Br or alkali metal bromides preferably KBr.
3. A process as claimed in claim 2 wherein the reagent preferred is KBr.
4. A process as claimed in claims 1 to 3 wherein the catalyst is selected from a suitable compound of Ti(IV), iron(lll), copper(ll), molybdenum(VI), tungsten(VI) or V2O5.
5. A process as claimed in claims 1 to 4 wherein the oxidising agent is selected from tert - butyl hydroperoxide or any other alkyl hydroperoxide or H2O2 as the oxidising agent.
6. A process as claimed in claims 1 to 5 wherein the oxidation of TBAB is carried out by using V2O5 as the catalyst and H2O2 as the oxidising agent and thereby producing a peroxo - vanadium (V) in the reaction which is responsible for actual oxidation.
7. A process as claimed in claims 4 to 6 wherein the oxidation is carried out by first preparing a water solution of the combination of a catalyst and an oxidizing agent followed by the addition to it, at a temperature below room temperature, an aqueous solution of an alkali bromide and TBAB.
8. A process as claimed in claim 7 wherein at the first stage requisite quantities of V2O5 and H2O2 are reacted at a temperature below room temperature.
9

9. A process as claimed in claim 7 wherein the solution of an alkali bromide and TBAB is provided in water which is added to an aqueous solution of the combination of a catalyst and an oxidizing agent and the reaction solution is maintained at a mild acidic pH attained by using H2SO4 or HCLO4 , preferably H2SO4.
10. A process for the preparation of isolable and storage stable tetrabutylammonium tribromide, (TBATB), from tetrabutylammonium bromide (TBAB) substantially as described herein with reference to accompanying examples.

Dated this 19 th day of January, 2000.
There is disclosed a process for the preparation of the isolable and storage stable tetrabutylammonium tribromide , (TBATB), from tetrabutylammonium bromide (TBAB), which comprises subjecting TBAB to oxidation in the presence of a catalyst, an oxidizing agent and an alkali bromide under mild acidic condition at a temperature below room temperature followed by recovery of the product and drying.

Documents:

00028-cal-2000-abstract.pdf

00028-cal-2000-assignment.pdf

00028-cal-2000-claims.pdf

00028-cal-2000-correspondence.pdf

00028-cal-2000-description(complete).pdf

00028-cal-2000-form-1.pdf

00028-cal-2000-form-13.pdf

00028-cal-2000-form-18.pdf

00028-cal-2000-form-2.pdf

00028-cal-2000-form-3.pdf

00028-cal-2000-form-5.pdf

00028-cal-2000-letters patent.pdf

00028-cal-2000-p.a.pdf

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Patent Number

205278

Indian Patent Application Number

28/CAL/2000

PG Journal Number

13/2007

Publication Date

30-Mar-2007

Grant Date

30-Mar-2007

Date of Filing

19-Jan-2000

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

INSTITUTION OF ENGINEERS BUILDING,PAN BAZAR GUWAHATI-781 001(ASSAM),INDIA, AN INDIAN EDUCATIONAL INSTITUTION.

Inventors:

#	Inventor's Name	Inventor's Address
1	MIHIR KANTI CHAUDHURI	PROFESSOR, DEPARTMENT OF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY,GUWAHATI 781 001(ASSAM)
2	ABU TALEB KHAN	ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY,GUWAHATI 781 001 (ASSAM)
3	BHISMA KUMAR PATEL	ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY,GUWAHATI 781 001(ASSAM)
4	BORA UPASANA	RESEARCH FELLOW,DEPARTMENT OF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY,GUWAHATI 781 001 (ASSAM) INDIA.

PCT International Classification Number

C 07C 209/68

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA