FORM-2
THE PATENTS ACT ,1970 (39 OF 1970)
COMPLETE SPECIFICATION (SEE SECTION 10)
PROCESS FOR PREPARATION OF 3,3 DICHLORO BENZEDINE HYDROCHLORIDE
Name and address of applicants: M/s. Sajjan India Limited,
Matulya Centre, #2Ground floor, Senapati Bapat Marg, Lower Parel, Mumbai 400 013, Maharashtra, India, Indian.
following specification particularly describes the nature of invention and the manner in which it is to be performed.

GRANTED

Original
153/MUM/2006 2 4 SEP 2007

(1) Field of the Invention
The present invention relates to a process for preparation of 3,3 DICHLORO BENZEDINE HYDROCHLORIDE. More particularly, the present invention relates to the process for preparing 3,3 DICHLORO BENZEDINE HYDROCHLORIDE using anhydrous HCL gas.
(2) The Prior Art
The preparation of 2,2 - DICHLOROHYDRAZOBENZEDINE is done by hydrogenation and/or catalytic reduction of 2,2 - Dichloroazoxybenzedine which is well known commercial process.
The use of such process has several disadvantages. For instance 2,2HYD is in toluene and when mixed with it will go mixed into 60% to 62% Sulphuric Acid. This process takes 25 to 30 hrs under 25°C. This is called rearrangement reaction. When the entire HBT will be mixed with 60% Sulphuric acid will heat upto 52°C to 57°C and thereafter TLC (Thin Layer Chromatography) will be checked in toluene to reveal if 2,2 HYD appears or not. When TLC okay, then water is add water to it at 55°C. Subsequent to the addition of water will heat the mass upto 88°C to 93°C. At this temperature, the entire mass in the reactor will be converted into two layers. The top layer will be that of toluene while the lower layer would be that of the clear liquid solution consisting of sulphuric acid, water and 2,2 HYD to give 3,3 Dichlorbenzidine sulphate solution. The two layers are then separated and toluene is removed by

distillation for reuse. There is loss of quantity of toluene and the waste effluent is removed in to the environment.
The lower layer is then heated to reach 88°C to 93°C so that the solution of 3,3 Dichlorbenzidine Sulphate solidifies. At the same temperature, some quantity of charcoal is addedto remove impurities. On getting a clear homogenous liquid solution the charcoal is filtered out from the mass. After clarification of charcoal the temperature of the sulphate solution will continue to be maintained between 88°C to 93°C.
In a new vessel a solution consisting of water having 25% of salt therein. The salt solution is also heated to 60°C to 70°C. The salt solution is added to the sulphate solution at 90°C. To this solution, further 30% HCL is added. This process is known as isolation. After charging of the HCL the cooling of entire mass will be started. The solution will be cooled to temperatures between 35°C to 40°C, when filter loss is checked. If filter loss is less than 1.5% of 3,3 Dichlorbenzidine Hydrochloride entire mass will be filtered through a nutsche. The cake on the filter is removed and made to dry to form 3,3 Dichlorbenzidine Hydrochloride. The filtered liquid solution is then put into effluent treatment plant for neutralization and reduction of COD and BOD as required by Pollution Control norms .

BRIEF SUMMARY OF THE INVENTION
The above and other objects of this invention are achieved by a process of hydrogenation and/or catalytic reduction of 2,2 - dichloroazoxybenzedine. A process for preparing 3,3 DichloroBenzedine Hydrochloride comprises, Mixing 2,2 Dichloroazyxobenzedine with organic solvent, preferably acetone, in stainless steel (SS) jacketed reactor with agitator; such as acetone in stainless steel jacketed reactor with agitator; adding Rene Nickel Catalyst to said reaction at temperature 30° C to 45°C; introducing hydrogen gas to said reactor still completion of hydrogenation reaction; filtering slurry of step (d in claim 1) to separate Rene Nickel Catalyst; treating the reaction mass of step (e in claim 1) with carbon; filtering the reaction mass of step (fin claim 1) to remove the carbon from reaction mixture; transferring the reaction mass of step (g in claim 1) to MS glass line reactor, treating the reaction mass of step (h in claim 1) with unhydrous HCL gas/liquid at temperature between 0C to 55C; Filtering precipitated slurry of step (i in claim 1) and filtering washing and drying the leftover cake to obtain 3,3 Dichloro Benzedine;
DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described more fully hereinafter.
There is provided the process for the preparation of 2,2-dichloroazoxybenzdine, which is mixed with any organic solvent especially acetone into a Stainless Steel (SS) jacketed reactor having an agitator stirrer. Agitation continues while alkali metal is

charged to get pH alkaline. Then catalyst Rene Nickel is charged at 30°C to 45°C. The process of hydrogenation is started by introducing hydrogen gases till the completion of the reaction. On completion of the reaction the Rene nickel is separated from the slurry (reaction mass) by filtration. To the remaining mass, carbon treatment is done. The carbon in the reaction mass is removed by filtration. Entire slurry is then transferred, into MS glass line reactor. To the reaction mass anhydrous HCL gas liquid HCL is introduced at 0°C to 55°C. After completion of reaction, precipitated slurry will be filtered and dried. The leftover cake on the filter is 3,3 dichlorobenzedine hydrochloride. The filtrate is mother liquid that is organic solvent used in this case acetone, which will be reused after distillation. The entire process takes 5 to 10 hrs. No effluent of any sort is released into the environment and/or the atmosphere.
The typical examples given below to describe the invention do not limit the compositional range covered under the spirit and scope of the invention.

DIAGRAM

Example
SS hydrogenator of 1 liter having mechanical seal stirrer to which 500 ml organic solvent especially acetone and 200 gms 2,2 - Dichloroazoxybenzedine are added and optionally 5 ml caustic lye is added to said hydrogenator as it its use is to speed the reaction and also to neutralize the HCL, which is generated during the reaction failing to add caustic lye would be harmful to the vessel as the same would otherwise be corroded. Further 20 gms of Rene Nickel catalyst will be charged to the solution under stirring. Until now, the reaction is being done at room temperature. Subsequent to the charging of the Rene Nickel catalyst, hydrogen gas is introduced in short intervals / gradually and the temperature is raised slowly. Care is taken that the

temperature does not exceed 65°C to 75°C. Accordingly, due to the increase of temperature the pressure is also raised to 8 to 12 kg. The process of hydrogenation is continued until completion of the process and the whole process requires approximately 10 to 12 gms of hydrogen gas. On completion of reaction the mass is then cooled to 25°C to 35°C and then transferred into another 3 neck round bottom flask that is fitted with a mechanical seal stirrer when the total mass transferred, the Rene Nickel catalyst is filtered through buckner funnel under vacuum and is fit for reuse. To the remaining solution, further 500 ml acetone addition is added. Subsequent to the addition of the acetone, further 40 to 50 gms of activated carbon is added to the transferred solution. The solution is then stirred continuously for a period between 20 to 35 mins. After the stirring the solution is filtered to remove the sludge of carbon in the solution. Thereafter the filtered solution put into another 3 neck round bottom flask fitted with mechanical seal stirrer. Into this flask 60 gms of HCL acid which may be in gaseous or liquid form is slowly introduced while the temperature is maintained between 20°C to 50°C. When the entire process of introduction of HCL is completed the mixture is continuously stirred for a period ranging between 5 to 7 hrs, within which time the whole reaction takes place. Then the reaction mass is filtered through a buckner funnel. The mother liquid consisting of mainly solvents is filtered and purified and then reused. The cake on the buckner funnel is then washed with an organic solvent to remove the impurities and is then dried. The dried cake is the final product which is 3,3 Dichlorbenzidine Hydrochloride.

On drying the yield of 3,3 Dichlorbenzidine Hydrochloride is 75% and the weight is 200gms.
This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.