Title of Invention	"A PROCESS FOR PREPARATION OF 3,3' DICHLORO 4,4' DIAMINO TRIPHENYL METHANE"
Abstract	This invention is relates to a process for preparation of 3, 3' Dichloro 4, 4' diamino triphenyl methane. The process comprises steps of condensation of mixture of purified ortho chloro aniline and benzaldehyde, mixing of the condensed mixture in methanol,. The precipitation of the synthesized product, and crystallization of 3, 3' dichloro 4, 4' Diamino triphenyl methane.

Full Text

FIELD OF INVENTION The invention relates to a process for the preparation of 3,3' dichloro 4,4' diamino triphenyl methane. PRIOR ART Polyurethane is basically a polymer, which is prepared using a diisocynate and a polyol (alcohol) as basic materials. Polyurethane lias wide applications and is used for making sealing material, printing roles, slabs. shoe-soles, foams etc. The reaction of isocynate and alcohol results in urethane linkage. During the synthesis of polyurethane, amines are also used to add specific properties to the polyurethane prepared in above manner. Amine provides necessary strength to the polyurethane while ' alcohol provides flexibility. So we need to mix judiciously amine and alcohol with insocynate for getting polyurethane having specific properties in terms of strength as well as flexibility. Further, aromatic amines are preferred for preparation of polyurethane over other various types of amines, due to their controlled rate of reaction with isocynate. Thus, controlled rate of reaction facilitates easy handling of the reaction process. Moreover, presence of aromatic rings results in polyurethane having good toughness and thermal stability. The most commonly used aromatic diamine for this purpose is methylene -bis-orthochloro aniline (MOCA). However, Polyurethane based on this amine ( methylene-bis- ortho- chloro aniline) suffers from many disadvantages. Primary disadvantage of methylene-bis- orthochloro aniline is that it * provides lesser elongation to the polyurethane. Another disadvantage of methylene -bis- ortho chloro aniline is that it is less thermally stable compound. Yet another disadvantage of methylene -bis- orthochloro aniline is that it is carcinogenic in nature. OBJECT OF THE INVENTION Primary object of the invention is to provide a process for preparing 3,3' dichloro 4,4' diamino triphenyl methane, with relatively elongation of the polyurethane. Another object of the invention is to provide a process for preparing 3,3' dichloro 4,4' diamino triphenyl methane, which does not require any solvent. Still another object of the invention is to provide a process for preparing 3,3' dichloro 4,4' diamino triphenyl methane, which results in higher strength of the polyurethane. Yet another object of the invention is to provide a process for preparing 3,3* dichloro 4,4' diamino triphenyl methane which can also be utilized as cross linker for epoxy curing which is ultimately used for preparing high strength composites and coating materials. Yet further object of the invention is to provide a process for preparaing 3,3' dichloro 4,4' diamino triphenyl methane which is simpler. DESCRIPTION OF THE INVENTION According to this invention there is provided a process for preparation of 3,3' Dichloro 4,4' diamino triphenyl methane, comprising of the steps of condensation as herein described of mixture of purified 2.5-2.7 mole of ortho chloro aniline and 1 mole of benzaldehyde, mixing as herein described of the condensed mixture in methanol and precipitation of the synthesised product, crystallistation of 3,3' dichloro 4,4' Diamino triphenyl methane by redissolving the residue of (c) in a solvent as herein described, refluxing the mixture and filtering at a temperature of 50-60°C, cooling to obtain of 3,3' Dichloro 4,4' diamino triphenyl methane . In accordance with this invention, there is provided a process for preparing 3,3'_dichloro 4,4'_diamino triphenyl methane, which can be utilised, for making polyurethane. The proposed diamine is a condensation product of ortho chloro aniline and benzaldehyde. The 3,3'_dichloro 4,4'_diamino triphenyl methane, prepared in the proposed manner, results in high strength polyurethane with higher elongation. The proposed process is simpler and easy to handle and it does not need any solvent for preparing 3,3'_ dichloro 4,4'_diamino triphenyl methane. The process comprises the step of distillation of orthochloro aniline, condensation of mixture of orthochloro aniline and benzaldehyde, mixing of condensed mixture with methanol, precipitation of synthesised product and crystallisation of 3,3'_dichloro 4,4'_diamino triphenyl methane. According to present invention, the process of preparing 3,3 dichloro 4,4' diamino triphenyl methane comprises of following steps. (i) Distillation of ortho chloro aniline The required quantity of ortho chloro aniline is purified by distilling in a distillate at around 90°C and reduced pressure. For one mole of benzaldehyde, the required amount of ortho chloro aniline is 2-4 moles, however, the preferred requirement of ortho chloro aniline is 2.5-2.7 moles. (ii) Condensation of Mixture of ortho chloro aniline and benzaldehvde The above specified quantities of ortho chloro aniline and benzaldehyde are charged into a three necked reaction vessel fitted with a stirrer, nitrogen inlet tube, thermometer and reflux condenser along with Dean Stark apparatus. The reaction is catalysed by using sulphuric acid or hydrochloric acid or phosphoric acid or zinc chloride or magnisium chloride etc. Preferably anhydrous zinc chloride is taken with molar ratio of Zncl2 to benzaldehyde varying from 0.5 to 0.75 mole. The reaction mixture is stirred under Nitrogen atmosphere at 100 to 130 °C for 20-24 hours. Next, the temperature is lowered at 50 °C and methanol is charged into the vessel to dissolve the entire viscous mass with continuous stirring. (iii) Precipitation of the synthesized product The entire solution is discharged from the vessel to a container containing 5 % alkali solution (sodium hydroxide) with continuous stirring The resultant precipitate is filtered and thoroughly washed with water to free it from alkali. The residue is dried in an air oven at 70-80 ° C. (iv) Crystallisation of 3.3' dichloro 4.4' diamino triphenyl methane The above dried residue is redissolved in methanol and contents are refluxed and filtered under hot condition (50-60°C) to remove impurities. The filtrate thus formed is concentrated by distilling off the excess methanol from the entire content. The concentrated solution is cooled for crystallisation. Finally, yellow coloured 3,3' dichloro 4,4' diamino triphenyl methane crystals are recovered and dried. The dried crystals are evaluated for chemical and phystical properties. The process of the present invention will now be illustrated with a working example which is intended to be a typical example to illustrate the working of the invention and is not intended to be taken restrictively to imply any limitation on the scope of the present invention. WORKING EXAMPLE: In order to prepare 100 gm of 3,3' dichloro 4,4' diamino triphenyl methane crystals, around 300 gm of ortho chloro aniline is distilled in a distillator at 90°C and at reduced pressure (10 mm of Hg). Around 250.8 gm of pure ortho chloro aniline and around 77.2 gm of benzaldehyde are charged into a three necked reaction vessel fitted with a stirrer. nitrogen inlet tube, thermometer and reflux condenser along with Dean Stark apparatus. 50 gm of zinc chloride is added as catalyst. The reaction mixture is stirred under nitrogen atmosphere at 130 °C for 20-24 hours. Next the temperature is lowered at 50 °C and methanol is charged into the vessel to dissolve the entire viscous mass with continuous stirring. The entire solution is discharged from the vessel to a container containing 5 % alkali solution (in sodium hydroxide) with continuous stirring. The resultant precipitate is filtered and thoroughly washed with water to free it from alkali. The residue is dried in an air oven at 70-80 °C. The above dried residue is redissolved in methanol and the contents are refluxed and filtered under hot condition (50-60 °C) to remove impurities. The filtrate thus formed is concentrated by distilling off the excess methanol from the entire content. The concentrated solution is cooled for crytallisation. Yellow coloured 3,3' dichloro 4.4" diamino triphenyl methane crystals are recovered and dried. The dried crystals are evaluated for chemical and physical properties. The purity of the compound was found to be 99.9 % as seen from elemental analysis.The melting point of the compound was 128.5°C as seen from Differential Scanning Calorimetry. It is to be understood that the process of present invention is susceptible to adaptations, changes, modifications by those skilled in the ait. Such adaptations, changes, modifications are intended to be within the scope of the present invention which is further set forth by following claims.s WE CLAIM 1. A process for preparation of 3,3' Dichloro 4,4' diamino triphenyl methane, comprising of the steps of: (a) condensation as herein described of mixture of purified 2.5-2.7 mole of ortho chloro aniline and 1 mole of benzaldehyde. (b) mixing as herein described of the condensed mixture in methanol and precipitation of the synthesised product. (c) crystallistation of 3,3' dichloro 4,4' Diamino triphenyl methane by redissolving the residue of (c) in a solvent as herein described, refluxing the mixture and filtering at a temperature of 50-60°C, cooling to obtain of 3,3' Dichloro 4,4' diamino triphenyl methane . 2. A process as claimed in claim 1, wherein orthochloro aniline is subject to the step of purification by distillation at reduced pressure of 10mm before condensation. 3. A process as claimed in claim 1, wherein for preparation of said mixture, 1 mole benzaldehyde is mixed with 2.4 moles of orthochloro aniline. 4. A process as claimed in claim 1, wherein said condensation is carried out under nitrogen atmosphere at 100 to 130°C for 20-24 hours followed by cooling at 50°C. 5. A process as claimed in claim 1, wherein for said condensation a catalyst such as sulphuric acid, hydrochloric acid, phosphoric acid or zinc chloride or magnesium chloride is used, preferably anhydrous zinc chloride. 6. A process as claimed in claim 1, wherein preferable ratio of anhydrous zinc chloride as catalyst to benzaldehyde is from 0.5 to 0.75 mole. 7. A process as claimed in claim 1, wherein the solvent used for crystallisation is methanol. 8. A process as claimed in claim 1, wherein 5% alkali solution preferably NaOH is used for said precipitation. 9. A process for preparation of 3,3' Dichloro 4,4' diamino triphenyl methane as substantially described and illustrated herein.

Documents:

439-del-2000-abstract.pdf

439-del-2000-claims.pdf

439-del-2000-correspondence-others.pdf

439-del-2000-correspondence-po.pdf

439-del-2000-description (complete).pdf

439-del-2000-form-1.pdf

439-del-2000-form-19.pdf

439-del-2000-form-2.pdf

439-del-2000-form-3.pdf

439-del-2000-gpa.pdf