Title of Invention

A PROCESS FOR PREPARATION OF 2,2 - DICHLOROHYDRAZOBENZENE

Abstract

OF KAYSER & CO APPLICANTS' ATTORNEYS There is provided a process for the preparation of 2,2-dichlorazoxybenzene which consists of adding water to a SS jacketed reactor having an agitator / stirrer. The water is agitated and to it is added alkali metal hydroxide at room temperature. On the dilution of the alkali metal hydroxide the temperature of the solution in the reactor rises which is controlled by cooling and a further charge of Ortho Nitro Chlorobenzene (ONCB ) is added to the mixture while agitation continues. Another charge of Diclone is introduced at controlled temperature to act as catalyst. This mixture in the reactor is continuously stirred and temperatures controlled until the solution becomes homogenous. Formaldehyde solution is added to the homogenous mixture in the reactor at a regulated Rate of addition during temperatures which controlled by jacket cooling. On completion Of the addition of the formaldehyde and the reaction 2,2-dichloroazoxybenzene is Separated from the reaction mass after washing it with water.

Full Text

FORM-2 THE PATENTS ACT, 1970 COMPLETE SPECIFICATION SECTION 10 TITLE :A PROCESS FOR PREPARATION OF 2,2-DICHLOROHYDRAZOBENZENE. APPLICANT (S): SAJJAN INDIA PRIVATE LIMITED, MATULYA CENTRE # 2 GROUND FLOOR, SENAPATI BAP AT MARG, LOWER PAREL, MUMBAI400 013, MARA.RASHTRA, INDIA. AND INDIAN COMPANY. The following Specification particularly describes the nature of this invention and the manner in which it is to be performed: - ORIGINAL 979/MUM/2003 (1) Field of the Invention The present invention relates to a process for the preparation of HYDRAZOBENZENE. More particularly, the present invention relates to a process for 2,2' -DICHLOROHYDRAZOBENZENE. (2) The Prior Art The preparation of 2,2' - DICHLOROHYDRAZOBENZENE is done by hydrogenation and or catalytic reduction of 2,2' - Dichloroazoxybenzene which is well known commercial process. The use of such process has several disadvantages. For instance, the use of alcohol / methanol is required as a solvent which can be reused provided the same is distilled. But inspite of the distillation of alcohol / methanol form water there is a loss of around 20% to 30 % which makes its way into the environment. The alkali metal hydroxide used in the existing processes is entirely lost on completion of the process as it is not possible for the same to be recovered and or retrieved for all or any useful purpose. Hence it becomes extremely necessary for manufacturers to install necessary equipment to prevent the pollution caused by aqueous effluents contaminated with the lost alcohol / methanol / alkali metal hydroxide and other bye products which are undesirable and harmful and need to be treated thoroughly before being discharged into the environment and or are 2 required to be incinerated at the costs of natural resources and money for making the chemical compound 2,2' - DICHLOROHYDRAZOBENZENE. It is therefore an object of the present invention to provide a process for producing 2,2'-dichlorohydrazobenzene without the use of alcohol or any of its variants. A further object of the present invention is to provide a method of hydrogenation or catalytic reduction of 2,2'-dichloroazoxybenzene with alkali metal hydroxide. And it is also the objective of this invention to enhance the production of 2,2'-dichlorohydrazobenzene by using less volume of reaction mass for achieving the desired production of 2,2'-dichlorohydrazobenzene. 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'-dichloroazoxybenzene. The present invention provides for the production of 2,2'-dichlorohydrazobenzene commercially through hydrogenation or catalytic reduction of 2,2'-dichloroazoxybenzene by using a process initiated by the use of an alkali metal hydroxide . The present invention further provides for the method of hydrogenation or catalytic reduction of 2,2'-dichloroazoxybenzene without the use of alcohol or its variant as a solvent. 3 Another aspect of this invention is to provide a method to produce 2,2' dichlorohydrazobenzene using less reaction mass volume and resources. The novelty of the process is the use of alkali metal hydroxide as initiator of the reaction process without the use of alcohol and or its variants as solvents. Accordingly there is provided a process for the preparation of 2,2' dichlorohydrazobenzene comprising the following steps, a) charging water and alkali metal hydroxide at room temperature in stainless steel jacketed reactor with constant stirring; b) adding ortho nitro chlorobenzene in the reaction mixture of step ( a ); c) charging catalyst Dichlone in the reaction mixture of step (b)with constant stirring till the mixture becomes homogenous; d) dosing formaldehyde at 40-45°cat intervals to obtain a reaction mass as thick paste of 2,2' dichloroazoxybenzene; 4 e) charging 2,2' dichloroazoxybenzene in molten state with alkali metal hydroxide at room temperature in stainless steel jacketed reactor with constant stirring; f) hydrogenating 2,2' dichloroazoxybenzene in presence of Raney nickel catalyst at 55-70°c by passing hydrogen gas to obtain crude 2,2' dichlorohydrazobenzene mixed with alkali metal hydroxide and catalyst; g) washing with water to separate the solid mass of 2,2' dichlorohydrazobenzene by filtration; h) dissolving the crude 2,2' dichlorohydrazobenzene in Toluene; i) separating solid mass of Raney nickel catalyst by filtration and the filtrate is washed with dilute mineral acid to obtain pure 2,2' dichlorohydrazobenzene; DETAILED DESCRIPTION OF THE INVENTION The present invention now will be described more fully hereinafter. There is provided a process for the preparation of 2,2'-dichloroazoxybenzene which consists of adding water to a SS jacketed reactor having an agitator / stirrer. The water is 5 agitated and to it is added alkali metal hydroxide at room temperature. On the dilution of the alkali metal hydroxide the temperature of the solution in the reactor rises which is controlled by cooling and a further charge of Ortho Nitro Chlorobenzene ( ONCB ) is added to the mixture while agitation continues. Another charge of Dichlone is introduced at controlled temperature to act as catalyst. The mixture in the reactor is continuously stirred and temperatures controlled until the solution becomes homogenous. Formaldehyde solution is added to the homogenous mixture in the reactor at a regulated rate of addition during temperatures is which controlled by jacket cooling. On completion of the addition of the formaldehyde and the reaction 2,2'-dichloroazoxybenzene is separated from the reaction mass after washing it with water. The process for the production of 2,2'-dichlorohydrazobenzene includes the following steps. In the feed vessel 2,2'-dichloroazoxybenzene is charged in a molten state. Alkali metal hydroxide solution is charged to 2,2'-dichloroazoxybenzene and agitated. The mixture is agitated at control temperatures and then transferred to hydrogenator in molten state keeping the temperatures constant. To the molten mixture a charge of Raney nickel catalyst is added and Hydrogen gas is introduced to so that the process of hydrogenation is initiated. Temperature and pressure are kept constant while the agitation of the molten reaction mass continues. Hydrogen is constantly being introduced into the reactor at constant temperature and pressure until the reaction completes. The excess of hydrogen is 6 removed by ventilation and nitrogen gas is introduced. The reaction mass contains 2,2'-dichlorohydrazobenzene, alkali metal hydroxide and other bye products. To separate the 2,2'-dichlorohydrazobenzene from the reaction mass, water is introduced to serve the purpose of cooling the reaction mass and also aiding in the separation of the 2,2'-dichlorohydrazobenzene from other by products and the aqueous solution by settlement. The aqueous solution containing the alkali metal hydroxide and other by products is siphoned leaving behind the solid mass of 2,2'-dichlorohydrazobenzene The solid mass of 2,2'-dichlorohydrazobenzene is further extracted in Toluene and Raney nickel catalyst is separated by filtration, thereby causing solid mass 2,2'-dichlorohydrazobenzene to be converted into a solution which is further purified by washing by dilute inorganic acid solution. The product 2,2'-dichlorohydrazobenzene is formed as a solution. Based on the desired real contents of the material ratio the quantity of 2,2'-dichloroazoxybenzene the size of the feed vessel is determined. The ss jacket reactor / feed vessel having a speed controlled agitator is then inerted with nitrogen and 2,2'-dichloroazoxybenzene is introduced into it under controlled temperatures ranging between 55° C - 65° C. The molten 2,2'-dichloroazoxybenzene is charged thereafter with alkali metal hydroxide. The material ratio of 2,2'-dichloroazoxybenzene and alkali metal hydroxide can vary from 1: 0.25 minimum to 1:1 maximum. Hereinafter referred to as the first part. 7 The first part of the reaction mass is then transferred to the hydrogenator at temperatures ranging between 55° C - 65° C, which is kept constant, while the mixing of the first part continues during the whole process. A further charge of Raney Nickel, to act as catalyst is added to the first part at a ratio of 1: 0.005, temperatures ranging between 55° C -65°C. Hereinafter referred to as Second Part. A further charge of the Second Part from the feed vessel to the hydrogenator under nitrogen gas. Hereinafter referred to as the third part. While the third part is being moved the temperatures of the hydrogenator is increased to temperatures between 55° C - 65° C and hydrogen gas is initially introduced to the feed vessel ventilate the nitrogen, while temperature and pressure are being controlled between 55° C - 90° C / 6 - 8 bar. The speed of the agitator continues to remain constant. The hydrogen is continuously introduced until the completion of the chemical reaction. On completion of the reaction hydrogen is stopped and cooling is commenced at constant pressure. When the reaction mass has cooled to half its initial temperature hydrogen pressure is vented and nitrogen gas is introduced to flush the hydrogen gas remaining. Hereinafter referred to as the fourth step. Water is added to the fourth step at a ratio of 1 : 1 and agitation is constant. Hereinafter referred to as the fifth step. The reaction mass of the fifth step is allowed to settle and the aqueous layer and the alkali metal hydroxide is separated. Thereby causing the recovery of alkali metal hydroxide at an approximate ratio of 1 : 0.97 to the initial volume used. After the hydrogenation process is complete, to separate the 2,2'-dichlorohydrazobenzene from the reaction mass, water is introduced to serve the purpose of cooling the reaction mass, separating the raw material for the preparation of 2,2' - dichloazoxybenzene and 8 also aiding in the separation of the 2,2'-dichlorohydrazobenzene from the aqueous solution by settlement / filtration. The composition of the aqueous solution consists of approximately 15% to 30% of the alkali metal hydroxide which is siphoned, filtered and collected to be recycled for the manufacture of 2,2' - dichloazoxybenzene. The solid mass left behind in the reactor is a solid mass of 2,2'-dichlorohydrazobenzene. The solid mass of 2,2'-dichlorohydrazobenzene is further extracted in Toluene and Raney nickel catalyst is separated by filtration, thereby causing 2,2'-dichlorohydrazobenzene solid mass to be converted into a solution which is further purified by washing of by dilute inorganic acid solution. The product 2,2'-dichlorohyrazobenzene is formed as a solution. The above described one-step method of hydrogenation or catalytic reduction is a typical one and does not limit the scope and spirit of process with changed sequencing and parameters such a concentration temperature, time, catalyst quantity and quality, material ratio, etc. to achieve the same end result. The process of hydrogenation or catalytic reduction of 2,2' dichlorohydrazobenzene offers numerous advantages in the process of hydrogenation or catalytic reduction of 2,2' dichlorohydrazobenzene over the process in which the use of solvent is imperative or necessary. For example, this hydrogenation process can be carried out in less volume of the reaction mass and utilization of resources. 9 The typical examples given below to describe the invention do not limit the compositional range covered under the spirit and scope of the invention. 350 gm, of 2,2'-Dichloroazoxybenzene and 10 gm washed Raney nickel catalyst is added to 150 ml of sodium hydroxide of 47% purity . The hydrogenation reaction carried out at 70-75 ° C under a hydrogen gas pressure 6-8 bar for 6 hrs. The reaction mixture is cooled and hydrogen gas vented. The reaction mixture is diluted with water. The aqueous solution left to cool and settle. The aqueous solution is then siphoned to leave behind the mass of 2,2' dichlorohydrazobenzene and is further filtered to separate the alkali metal hydroxide. The and the product is isolated by filtration and extracted in toluene. The yield of 2,2'-Dichlorohydrazobenzene is 288 gm (87 % of theory) Variations Yield is more than 55 % 10 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 folly convey the scope of the invention to those skilled in the art. 11 I CLAIM, 1) A process for the preparation of 2,2' dichlorohydrazobenzene comprising the following steps, a) charging water and alkali metal hydroxide at room temperature in stainless steel jacketed reactor with constant stirring; b) adding ortho nitro chlorobenzene in the reaction mixture of step ( a); c) charging catalyst Dichlone in the reaction mixture of step ( b)with constant stirring till the mixture becomes homogenous; d) dosing formaldehyde at 40- 45°c at intervals to obtain a reaction mass as thick paste of 2,2' dichloroazoxybenzene; e) charging 2,2' dichloroazoxybenzene in molten state with alkali metal hydroxide at room temperature in stainless steel jacketed reactor with constant stirring; 12 f) hydrogenating 2,2' dichloroazoxybenzene in presence of Raney nickel catalyst at 55-70°c by passing hydrogen gas to obtain crude 2,2 dichloroazobenzene mixed with alkali metal hydroxide and catalyst; g) washing with water to separate the solid mass of 2,2' dichlorohydrazobenzene by filtration; h) separating the dilute alkali metal hydroxide ( 15% to 30% ) by siphoning; i) recovering the dilute alkali metal hydroxide up to 80% to 97% from the hydrogenated mass solution; j) dissolving the crude 2,2' dichlorohydrazobenzene in Toluene; k) separating solid mass of Raney nickel catalyst by filtration and the filtrate is washed with dilute mineral acid to obtain pure 2,2' dichlorohydrazobenzene; 2) A process for the preparation of 2,2' dichlorohydrazobenzene as claimed in claim 1 wherein mineral acid is preferably hydrochloric acid. 13 3) A process for the preparation of 2,2' dichlorohydrazobenzene as claimed in claim 1 wherein the alkali metal hydroxide used is recovered up to 97 % by dilution, siphoning and filtration. 4) A process for the preparation of 2,2' dichlorohydrazobenzene as claimed in claim 1 wherein temperature is maintained at room temperature by supplying chilled water through the jacket in the reactor. 5) A process for the preparation of 2,2' dichlorohydrazobenzene as claimed in claim 1 wherein the material ratio of 2,2' dichloroazoxybenzene and alkali metal hydroxide can vary from 1: 0.25 minimum to 1:1 maximum. 14DATED THIS 19 DAY OF SEPTEMBER, 2003.

Documents:

979-mum-2003-abstract (09-05-2004).doc

979-mum-2003-abstract(19-05-2004).pdf

979-mum-2003-cancelled pages(19-05-2003).pdf

979-mum-2003-claims(granted)-(19-05-2003).doc

979-mum-2003-claims(granted)-(19-05-2003).pdf

979-mum-2003-correspondence(18-10-2005).pdf

979-mum-2003-correspondence(ipo)-(19-04-2007).pdf

979-mum-2003-form 1(19-09-2003).pdf

979-mum-2003-form 19(22-10-2003).pdf

979-mum-2003-form 2(granted)-(19-05-2003).doc

979-mum-2003-form 2(granted)-(19-05-2003).pdf

979-mum-2003-form 26(17-09-2003).pdf

979-mum-2003-form 3(19-09-2003).pdf