Title of Invention

A PROCESS FOR THE PREPARATION OF 1,3,5-TRIAMINO-2,4,6-TRINITROBENZENE

Abstract

This invention relates to a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) comprising the steps of loading 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), taken 6-8% by weight of the total reactant mixture (puriry 85-90%), in a self-sealed, thoroughly cleaned and dried reactor; adding toluene, taken 40-80% by weight of the total reactant mixture, to said reactor and dissolving the said 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) in the said toluene uniformly by application of stirring characterized in that; mixing urea, taken 6-8% by weight of the total reactant mixture in said steel reactor containing said l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) dissolved uniformly in the said toluene, adding water with urea to reduce its consumption, taken 2-4% by weight of the total reactant mixture; aminating the said 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) by heating the said reactor containing the entire mixture obtained by steps (i), (ii) and (iii) to less than 160°C and allowing the reaction to take place under mechanical stirring maintained between 80-100 rpm, cooling said reactor by circulating chilled water through it after completion of the said reaction; releasing of the pressure built inside the said reactor through the vent valve, decanting the saia toluene after opening the said reactor, adding equal volume of distilled water and sealing the said reactor once again for heating purpose; digesting the entire mix obtained from step (vi) for about 1-2 hours at about 90-100°C by heating the said reactor to 90-100°C within 15-20 minutes; filtering the hot slurry by opening the said reactor after completion of the said digesting of the said mix and drying the TATB cakes, thus obtained, in a oven at 90-100 C for 2-3 hours to remove moisture after clqaning it with acetone.

Full Text

field of Invention: This invention relates to a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene(TATB). Prior Art: In many modern applications of high explosives, it is required to have improved safety and stability of the explosives at higher temperatures. Conventionally, TNT, RDX and HMX are used as high explosives. However, 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) is preferred over these conventional high explosives due to it's better characteristics. This is widely used as an insensitive high explosive for its extraordinary resistance to heat, high density and accelerated detonation properties with respect to military explosives such as TNT, RDX and HMX. High thermal stability and extreme insensitivity make TATB highly desirable in applications where prevention of accidental detonation is a primary consideration. Further, coarse grained TATB of average particle size greater than 50 microns is generally preferred when the explosive is to be poured or pressed. The coarse grained TATB also give better solid loading in case of sheet explosive preparation. One of the processes for the preparation of TATB, known in the prior art as disclosed in US Patent No. 4481371, involves amination of 1,3,5-trichloro-2,4,6 -trinitrobenzene (TCTNB). Conventionally, the amination process involves dissolving of trichlorotrinitrobenzene in a solvent like toluene and purging of ammonia gas through this solution. At the end of the amination process, TATB powder is obtained. However, this process for the preparation of TATB, known in the prior art, suffers from the following disadvantages. Primary disadvantage of this process for the preparation of triaminotrinitrobenzene (TATB), known in the prior art, is that it can produce only fine grain triaminotrinitrobenzene powder having maximum average particle size of about 50 microns only Another disadvantage of this process for the preparation of triaminotrinitrobenzene, known in the prior art, is that it utilises ammonia gas for the amination which is toxic and hazardous to handle. Yet another disadvantage of this process for the preparation of triaminotrinitrobenzene, known in the prior art, is that the chloride impurity content in the finally produced triaminotrinitrobenzene is on the higher side which affects it's storage life. Another process for the preparation of triaminotrinitrobenzene, known in the prior art as disclosed in US Patent No. 4439622, involves amination of molten TCTNB by urea in the presence of an antioxidant. Although, this process produces TATB of higher average particle size, this process also suffers from the following disadvantages. Prirmary disadvantage of this process, known in the prior art, is that it utilises highly uncommon antioxidant. Another disadvantage of this process, known in the prior art, is that the consumption of urea in the amination process is on the higher side. Yet another disadvantage of this process, known in the prior art, is that the process involves utilizing TCTNB and urea in molten condition which is difficult to perform. Still another disadvantage of this process, known in the prior art, is that the final yield of the product is on the lower side. Objects of the invention: Primary object of the invention is to provide a process for the preparation of triaminotrinitrobenzene, which is capable of providing 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) of higher particle size ranging from 50 to 100 microns. Another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which is nontoxic, safe and which utilizes inexpensive raw material. Yet further object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which has a higher yield for production of 1,3,5-triamino-2,4,6-trinitrobenzene. Yet another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which results in production of 1,3,5-triamino-2,4,6-trinitrobenzene with lesser chloride impurity content. Still another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which uses water in addition to amination agent urea thereby reducing the consumption of urea for the amination process. Yet another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which reuses amination effluent solvent generated in the previous amination process. Still another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene, which uses an inexpensive antioxidant and thereby reduces the cost of the process. Yet another object of the invention is to provide a process for the preparation of 1,3,5-triamino-2,4,6-trinifr:obenzene,- which a simpler batch process rather than semi batch process. Still Yet another object of the invention is to provide a process for the preparation of 1,3,5-triamind-2,4,6-trinitrobenzene, in which the reaction is Completed below 160°C thereby improving the product quality and dispensing with need of antioxidants. Description of the Process; The present invention involves the amination of TCTNB in toluene medium in a sealed reactor using urea as the animating agent. The reaction is carried out in the presence of water at temperatures The presence of water reduces the consumption of the aminating agent, urea and it is also reduces the chloride impurities occluded in the product TATB in the form of ammonium chloride. In the presence of water, urea slowly decomposes to ammonia and carbon dioxide at a temperature above 130°C. While, in the absence of water, urea decomposes to ammonia and cyanic acid. Both of these reactions have been shown in the following. NH2CONH2 + H2O—»2NH3 + CO2 NH2CONH2—»NH3+HNCO From the above, it is obvious that the evolution of ammonia in presence of water is almost double as compared to the case when water is not used during the amination process. Hence, the consumption of urea is reduced when the amination is carried out in the presence of water. When the amination is carried out in the presence of water, the by-product ammonium chloride deliquesces and assumes a semi liquid form, which is not capable of serving as a nucleation center for TATB crystal growth. This helps in reducing the chloride impurity content. The amination of TCTNB at high temperatures (>160°C) leads to oxidation of product TATB resulting in darkening of bright yellow coloured product TATB. The presence of small amount antioxidant thwarts the degradation's of product TATB at higher temperature. The process for preparation of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) comprises of following steps: (i) Loading of 1.3.5-trichloro-2.4.6-trinitrobenzene (TCTNB) in stainless steel reactor A 1.8 litre self -sealed stainless steel reactor equipped with an agitator containing four turbine type blade and a pressure vent valve is thoroughly cleaned with acetone and dried. TCTNB, taken 6-8% by weight of the total reactant mixture (purity 85-90 %), is loaded in this reactor. (ii) Addition of toluene to TCTNB in the stainless steel reactor To the above reactor, toluene taken 40-80 % by weight of the total reactant mixture is added. TCTNB is allowed to dissolved uniformly in toluene by application of mechanical stirring. (iii) Mixing of urea and water in the stainless steel reactor Next, to the above solution, aminating agent urea taken 6-8 % by weight of the total reactant mixture is added. Water, taken 2-45% by weight of the total reactant mixture, is also added to the above solution. A surfactant sodiumdodecylsulphate and an antioxidant butylatedhydroxytolune, both taken about 0-0.5 % by weight, are also added as optional ingredients. (iv) Aminatinq 1.3.5-trichloro-2.4.6-trinitrobenzene (TCTNB) by heating of the reaction mixture The reactor containing the entire mixture obtained by steps (i),(ii) and (III) is sealed and is heated through an external electrical heating arrangement. The temperature of the reactor is raised between 150-160 °C within 1 hours time . The heating iss done under stirring condition of 80-100 rpm. The reaction, inside the reactor, is allowed to take place for about 3-5 hours. The rpm of the stirrer is maintained between 80-100 during this period. As a result of heating, the pressure inside the reactor slowly increases from 2 to 35 bar (max). (v) Cooling of the reaction mixture After the completion of the reaction, the reactor is cooled to 60 °C within 20-30 min. by circulating chilled water through it. (vi) Releasing of the reactor pressure After cooling of the reactor, the pressure inside the reactor is released through the vent valve. The reactor is opened and toluene is decanted off. Next, equal volume of distilled water is fed into the system and reactor is-once again sealed. At.this stage, the reactor contains yellow colored TATB, ammonium chloride unutilised urea. (vii) Digestion of reaction mixture Next, the sealed reactor is again heated through the external electrical heating arrangement and the temperature is raised to 90-100 °C within 15-20 minutes. The entire mix is digested with water at 90-100 °C for 1-2 hours. (viii) Filtration and drying After the completion of the digestion process, the reactor is opened and the slurry is taken out in a beaker through flash bottom valve of the reactor. The slurry is filtered in hot condition and washed with acetone 2-3 times to remove impurities. Finally, TATB cakes, thus obtained, are dried in a oven at 90-100°C for 2-3 hours to remove moisture. The invention will now be illustrated with working examples, which are typical examples to illustrate the working of the invention and are not intended to be taken restrictively to imply any limitation on the scope of the present invention. Working Examples Working Example-1 Amination of 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) was carried out in the sealed reactor at 150-160°C in toluene-water mixture. 100 gm TCTNB, 100 gm urea, 23 gm distilled water and 1.2 liter of toluene (density=0.87g/cc) were charged in the 1.8 liter Stainless steel reactor equipped with stirrer having four-blade turbine type impeller. RPM of the stirrer was kept at 80-100. The temperature of the reactor was raised to 150-160°C by external electrical heating arrangement and the reaction was carried out for three and half hours. The maximum pressure developed inside the reactor was recorded as 14 bars. The reaction mixture was cooled to 60°C by circulation of chilled water through it. After cooling, toluene was decanted out and an equal volume of water was fed into the reactor. Solid TATB was digested in water at 90°C for one and half-hours to remove ammonium chloride and unreacted urea. The slurry was filtered in hot condition and washed with acetone three times to remove impurities. The TATB cake was dried in oven and finally 65gm of product was isolated which was characterised for the properties illustrated in Table-1. Table-1 Characteristics of TATB synthesized as mentioned in Example-1 (Table Removed) Working Example-2 The amination of 100 gm 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) was performed in 1.2 liter of effluent toluene generated in previous amination process by addition of 100 gm urea and 29 gm of distilled water at temperature of 155°C in a sealed reactor equipped with stirrer for 3 .5 hours. The pressure observed inside the reactor was 20 bars. After the reaction, the system was cooled to 60°C and pressure was released. The toluene was decanted out and an equal quantity of distilled water was added. The TATB produced was digested with distilled water at 90°C for 1hour. The product TATB was filtered out and washed with sufficient quantity of acetone. It was dried in oven at 100°C for 1hour. The weight of the final product was found 69 gm which was characterised for following properties illustrated in Table-2. Table-2. Characteristics of TATB synthesized as mentioned in Example-2 (Table Removed) Working Example -3 The amination of 100 gm crude 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) was performed in a mixture of 600 ml of toluene and 600 ml distilled water with 100 gm urea in the presence of 3.0 g, sodium dodeeylsulphate and 3.0g antioxidant, butylatedhydroxytoluene (BHT) in the sealed reactor at a temperature of about 160° C for 3 hours. The pressure inside the reactor was slowly increased to 35 bars. After the reaction, the reactor was cooled and pressure was released. The yellowish brown colour solid TATB was isolated as cake after the filtration of the slurry. It was then washed with hot water, acetone and finally dried in a oven at 90°C for one and half hours . The weight of the final product TATB was found 73 gm. The other properties of isolated dry TATB were evaluated and illustrated in Table-3. Table-3 Characteristics of TATB synthesized as mentioned in Example-3 (Table Removed) It is to be understood that the process of the preswent invention is susceptible to adaptation, changes and modifications by those skilled in the art. Such adaptations, changes and modifications are intended to be within the scope of the present invention, which is further set forth with the following claims. WE CLAIM; 1. A process for the preparation of l,3,5-triamino-2,4,6-trinitrobenzene (TATB) comprising the steps of: i) loading l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), taken 6-8% by weight of the total reactant mixture (purity 85-90%), in a self-sealed, thoroughly cleaned and dried reactor; ii) adding toluene,; taken 40-80% by weight of the total reactant mixture, to said reactor and dissolving the said 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) in the said toluene uniformly by application of stirring characterized in that; iii) mixing urea, taken 6-8% by weight of the total reactant mixture in said steel reactor containing said l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) dissolved uniformly in the said toluene, adding water with urea to reduce its consumption, taken 2-4% by weight of the: total reactant mixture; iv) aminating the said l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) by heating the said reactor containing the entire mixture obtained by steps (i), (ii) and (iii) to less thanl60°C and allowing the reaction to take place under mechanical stirring maintained between 80-100 rpm, v) cooling said reaptor by circulating chilled water through it after completion of the said reaction; vi) releasing of the pressure built inside the said reactor through the vent valve, decanting the said toluene after opening the said reactor, adding .equal volume of distilled water and sealing the said reactor once again for heating purpose; vii) digesting the entire mix obtained from step (vi) for about 1-2 hours at about 90-100°C by heating the said reactor to 90-100°C within 15-20 minutes; viii) filtering the hot slurry by opening the said reactor after completion of the said digesting of the said mix and drying the TATB cakes, thus obtained, in a oven at 90-100 C for 2-3 hours to remove moisture after cleaning it with acetone. 2. A process as claimed in claim 1 wherein the average particle size of the said l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) produced is from 50-100 microns. 3. A process as claimed in claim 1 which reuses amination effluent solvent generated in the previous amination process. 4. A process for the preparation of l,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), substantially as herein described and illustrated.

Documents:

1114-DEL-2002-Abstract-(15-10-2009).pdf

1114-DEL-2002-Abstract-(30-09-2008).pdf

1114-del-2002-abstract.pdf

1114-DEL-2002-Claims-(15-10-2009).pdf

1114-DEL-2002-Claims-(30-09-2008).pdf

1114-del-2002-claims.pdf

1114-DEL-2002-Correspondence-Others (15-10-2009).pdf

1114-DEL-2002-Correspondence-Others-(12-11-2008).pdf

1114-DEL-2002-Correspondence-Others-(13-08-2009).pdf

1114-DEL-2002-Correspondence-Others-(30-09-2008).pdf

1114-del-2002-correspondence-others.pdf

1114-del-2002-correspondence-po.pdf

1114-DEL-2002-Description (Complete)-(15-10-2009).pdf

1114-del-2002-description (complete).pdf

1114-del-2002-form-1.pdf

1114-DEL-2002-Form-2-(30-09-2008).pdf

1114-del-2002-form-2.pdf

1114-del-2002-form-3.pdf

1114-del-2002-form-5.pdf

1114-DEL-2002-GPA-(12-11-2008).pdf

1114-DEL-2002-GPA-(15-10-2009).pdf