Title of Invention

N,N-DISUBSTITUTED PARA-PHENYLENE DIAMINES AND A PROCESS FOR THE PREPARATION THEREOF

Abstract

The present invention relates to N,N -disubstituted para-phenylene diamines and a process for the preparation thereof comprising dissolving a hindered phenol with liquid bromine in a non-polar organic solvent at a temperature in the range of 80-95°C for a period of 4-7hrs,evaporating the solvent under reduced pressure to obtain 3,5-di tert-butyl-4-hydroxy benzyl bromide,reacting with N,N-disubstituted para-phenylene diamines in the presence of tetrahydrofuran using a mild base at a temperature in the range of 80-95°C for a period of 4-7hrs to produce N,N -disubstituted para-phenylene diamines.

Full Text

N,N-Disubstituted Para-Phenylene Diamines And A Process For The Preparation Thereof Field of the invention This invention relates to the preparation of novel antiozonant as well as antioxidant based on functionalized hindered phenol and the process for the preparation thereof. More particularly it relates to the said absorber having a formula 1: (Formula Removed) wherein RI is tert-butyl and R2 and R3 are C1 to C8 linear or branched alkyl. Still more particularly, the invention relates to novel antiozonant as well as antioxidant based on functionalized hindered phenols and useful as condensable monomer for the synthesis of many polymers with in-built antioxidants and the process for the synthesis thereof. Co-pending application Sr. No. relates to the novel antiozonant as well as antioxidant based on functionalized hindered phenol obtained by the process of this invention. More particularly the present invention relates to the preparation of said novel antiozonant and antioxidant, using compound of formula 2 (Formula Removed) wherein R1 is a tertiary butyl group and X is Br, which is prepared by the halogenation of a hindered phenol of the general Formula 3 (Formula Removed) wherein R1 is tert-butyl with a compound having general Formula 4 (Figure Removed) wherein R2 and R3 are C\ to C8 linear or branched alkyl. Background of the invention Hindered phenols have been used as stabilizers in foodstuffs, rubber, plastics, oils etc. since long. Polymers have replaced metals, glass, ceramics and papers in packaging, automobiles, building construction, electronics, electrical equipment, furniture, pipes and heavy industrial equipments. In a nutshell, from agriculture to transport and aerospace to food packaging, the use of plastics have become integral parts of our daily life. Polymers, all natural and synthetic, in common use, are susceptible to thermal/ photo-oxidative degradation upon exposure to natural and artificial weathering. The deterioration of these polymeric materials is mainly due to the heat and UV portion of sunlight reaching the earth surface. The net result of degradation is the loss in the molecular weight and macroscopic physical properties. In order to avoid this loss, different types of stabilizers have been devised that protect the polymeric substrate from detrimental effect of heat and light. This invention relates to N,N-di substituted para-phenylene diamines as representing compound of Formula 1 which offer protection to polymers such as natural rubber and elastomers against the deteriorous effects of oxygen and ozone. It also relates to the methods for the preparation and use of these materials and to the compositions formed by mixing these materials with polymers. Para-phenylene diamines have been used as antioxidants and antiozonants since long. Following patents and literature provide information about synthesis of the antioxidants and antiozonants and their uses. For example, U.S. Pat. No. 3,644,482 describes hindered phenol stabilizers based on esters of 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. N-alkyl, N'-phenyl-p-phenylene diamines are revealed in U.S. Patent Nos. 3,409,586; 4 713; 3,542,691; 3,663,505 and 3,839,275 and British Patent No. 1,035,262. Sulphur containing para-phenylene diamines are disclosed in U.S. Patent No. 3,035,014. In addition, aromatic amines have also been revealed in U.S. Patent No. 3,505,225 as antioxidants based on a-methylstyryl-substituted diphenylamines. In addition, U.S. Pat. Nos. 4,797,511 and 4,837,259 describe the synergistic blends of hindered phenols and amine antioxidants as stabilizers for polypropylene and polyethylene. U.S. Pat. No. 3,304,283 discloses an antioxidant composition for mono-olefinic polymers, containing at least one aromatic phenolic thioether, diaryl thioether. aliphatic disulfide, aromatic disulfide and/or aliphatic thiuramdisulfide in combination with at least one biphenol and/or aromatic amine. The mixtures of an amine component and a sterically hindered phenol component with and without other ingredients are also revealed in U.S. Pat. Nos. 3,432,578; 3,567,664; 3,637,865; 3,655,559; 5,834,544 and 5,120,844. The one step acid catalyzed reaction with thiols, formaldehyde and aromatic amines is known in the prior art (J. Org. Chem., 24, 1035 (1959); J. Org. Chem., 28, 2763 (1963) and J. Org. Chem., 30, 28 (1965). As known to the skilled in the art, degradation of rubber from ozone manifests itself by (i) crack appearing perpendicular to the stress in the rubber the appearance of a silvery film on the surface of the article. The attack of ozone is a surface phenomenon. The function of the antiozonant depends on migration to the surface of the rubber article. Objects of the invention The main object of the present invention is therefore, to provide a novel antiozonant as well as antioxidant based on functionalized hindered phenol and a process for the preparation thereof, which can fulfill the prerequisites of a polymer stabilizer and can be synergistically used with other polymer stabilizers. Moreover, this class of combination of hindered phenols and diamines are known to be compatible with polyolefins, polycarbonate, polystyrene and diene-elastomers and can even be added in an additive proportion to obtain desired thermal stability of various other polymers. Summary of the invention The present invention provides a novel combination of antioxidant and antiozonant based on functionalized hindered phenol of the formula 1 (Figure Removed) Accordingly the present invention provides a process process for the preparation of novel antioxidant cum antiozonant of the formula 1 below (Formula Removed) Which comprises dissolving a compound of formula 3 (Formula Removed) Wherein R1 is tert-butyl,with bromine in a non-polar organic solvent at a temperature in the range of 80-95°C for a period of 4-7hrs,evaporating the solvent under reduced pressure to obtain a compound of formula 2. (Formula Removed) Wherein R1 is tert-butyl group and X is Br.reacting the compound of general Formula 2 with compound of Formula4 (Formula Removed) wherein R2 and R3 are C1 to C8 linear or branched alkyl.in the presence of an organic solvent using a mild base at a temperature in the range of 80-95°C for a period of 4-7hrs,bringing the reaction mixture to room temperature.separating the organic layer and concentrating the product and purifying the final product of Formula 1. In one embodiment of the present invention, the neutral organic solvent used for dissolving the compound of formula 3 is a chlorinated solvent selected from the group consisting of carbon tetrachloride, chloroform, chlorobenzene and dichloromethane. In another embodiment of the invention, the bromination of compound of formula 3 is achieved by using liquid bromine. In still another embodiment of the invention, the para-phenylene diamine of formula 4 is selected from N,N-dimethyl-para-phenylene diamine, N,N-diethyl-para-phenylene diamine, 2,5-dimethyl-para-phenylene diamine and 2,5-diethyl-para-phenylene diamine. In still another embodiment of the invention, the solvent used to dissolve the paraphenylene diamine is tetrahydrofuran (THF). In still another embodiment of the invention, the inorganic base used to basify paraphenylene diamine is selected from carbonates or bi-carbonates of alkali metals such as potassium carbonate sodium carbonate, potassium bicarbonate and sodium bicarbonate. In another embodiment of the invention, the product of formula 1 is concentrated by solvent evaporation under reduced pressure and purified by silica gel chromatography. Detailed description of the invention The present invention provides a novel combination of antioxidant and antiozonant based on functionalized hindered phenol of the formula 1 (Figure Removed) wherein R1 is tert-butyl and R2 and R3 are C1 to C8 linear or branched alkyl. The novel antioxidant cum antiozonant of the invention is prepared by dissolving a compound of formula 3 (Figure Removed) wherein R1 is tert-butyl, with bromine in a non polar organic solvent at a temperature in the range of 80 to 95°C for a period of 4 to 7 hours, evaporating the solvent under reduced pressure to obtain a compound of formula 2 (Figure Removed) wherein R1 is a tertiary butyl group and X is Br, reacting the compound of general (Figure Removed) with compound of formula 4 (Figure Removed) wherein R2 and R3 are d to C8 linear or branched alkyl, in presence of an organic solvent using a mild base at a temperature in the range of 80 to 95 °C for a period of 4 to 7 hours, bringing the reaction mixture to room temperature, separating the organic layer and. concentrating the product by solvent evaporation under reduced pressure and purifying the final product of formula 1 using silica gel column chromatography. The neutral organic solvent used for dissolving the compound of formula 3 is a chlorinated solvent selected from the group consisting of carbon tetrachloride, chloroform, chlorobenzene and dichloromethane. Bromination of compound of formula 3 is achieved by using liquid bromine. The para-phenylene diamine of formula 4 is selected from N,Ndimethyl- para-phenylene diamine, N,N-diethyl-para-phenylene diamine, 2,5-dimethyl-paraphenylene diamine and 2,5-diethyl-para-phenylene diamine. The solvent used to dissolve the para-phenylene diamine is tetrahydrofuran (THF) while the inorganic base used to basify para-phenylene diamine is selected from carbonates or bi-carbonates of alkali metals such as potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate. The process of the present invention is described herein below with references to that are illustrative only and should not be constructed to limit the scope of the present invention in any manner whatsoever. Example 1: Synthesis of 3,5-di-tert-butyl-4-hydroxy benzyl bromide In a 250 mi three-necked round bottom flask, 2.5 g (0.0113 mol) of 2,6-di-tert-butyll- 4-methyl phenol was dissolved in 50 mL of dry carbon tetrachloride. In a separate conical flask 1.83 g (0.589 mL, 0.0115 mol) of bromine was dissolved in 50 mL of dry carbon tetrachloride and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottom flask containing solution of 2,6-di-tert-butyl-4-methyl phenol was kept in oil-bath at 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. Bromine solution was added, drop-by-drop, from funnel to the flask for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final reaction mixture was allowed to cool at room temperature. The product isolated by solvent evaporation was a viscous yellow liquid and was absolutely pure. The yield of 3,5-di-tert-buty 1-4-hydroxy benzyl bromide or 4-bromomethyl-2,6-di-tert-butylphenol was }.05 g (90 %). Example 2; Synthesis of 4-[(4-Amimo-phearylamino)-methyl]-2,6-di-tert-butyl-phenol 4-Bromomethyl-2,6-di-tert-butyl-phenol (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran. In a separate conical flask benzene-1,4-diamine (p-PDA) (1.728 g, 0.016 mole) was dissolved in 25 mL of tetrahydrofuran and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottom flask containing solution of 4-Bromemethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at 85°C. Solution is the flask was continuously stirred with the help of magnetic stirrer. Benzene-1,4-diamine solution was added drop-by-drop, from funnel to the flask in acidic medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final? reaction mixture was allowed to attain room temperature. The product was purified using* silica gel column chromatography. Product was identified by 'H-NMR. The yield of 4-[(4- Amino-phenylamino)-methyI]-2,6-di-tert-butyl-phenol was 2.24 g (85 %). Example 3: Synthesis of 2,6-di-tert-butyl-4-[(4-dimethyIamino-phenylamino)-metbylJphenol 4-Bromomethyl-2,6-di-tert-butyl-phenol (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran. In a separate conical flask N,N-dimethyl-benzene-1,4-diamine (2.17 g, 0.016 mole) was dissolved in 25 mL of tetrahydrofuran and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottom flask containing solution of 4-Bromomethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. N, N-dimethyl-paraphenylene diamine solution was added drop-by-drop, from funnel to the flask in acidic medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated afters to attain room temperature The product was purified using silica gel column chromatography. Product was identified by 'H-NMR. The yield of 2,6-di-tert-butyl-4-f(4-dimethylaraino-phenylamino)- methyl]-phenol is 1.80 g (63 %). Example 4: Synthesis of 4-((4-Amino-2,5-dimethyl-phenylamino)-2,6-di-tert-butylphenol 4-Bromomethyl-2,6-di-tert-butyl-phenol (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran. In a separate conical flask 2,5-dimethyl-benzene-l,4-diamine ( 2.17 g, 0.016 mole) was dissolved in 25 mL of tetrahydrofuran and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottom flask containing solution of 4-Bromomethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. 2,5-dimethyl-para~ phenylene diamine solution was added drop-by-drop, from runnel to the flask in acidic, medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final reaction mixture was allowed to attain room temperature. Product was separated by solvent evaporation. The product was purified using silica gel column chromatography. Product was identified by 'H-NMR. The yield of 4-[(4-Amino-2- dimethyl-phenylamino)-2,6-di-tert-butyl-phenel is 1.86 g (65 %). Example 5: Synthesis of 2,6-di-tert-butyl-4-{[4-(l,4-dimethyI-pentylamino)- phenylamino)-methyl}-phenol 4-Bromomethyl-2,6-di-tert-butyl-phenol (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran. In a, separate conical flask N-(l,4-Dimethyl-pentyl)-benzene-l,4- diamine (3.28 g, 0.016 mole) was dissolved in 25 mL of tetrahydrofuran and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottom flask containing solution of 4-Bromomethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at temperature 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. N-(l,4-Dimethyl-pentyl)-benzene-l,4-diamine solution was added drop-by-drop, from funnel to the flask in acidic medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final reaction mixture was allowed to attain room temperature. Product was separated by evaporation. The product was purified using silica gel column chromatography was identified by H-NMR. The yield of 2,6-di-tert-butyI-4-{[4-(l,4-dimethyl-pentyIamino)-phenylamino)-methyl}- phenol is 2. 29 g (67 %). Example 6: Synthesis of 2,6-di-^rr-butyl-4-|(4-phenylamino-phenylamino)-phenol 4 - M i 4 e r t 4 w t y l - p i i e i i Q l (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran . In a separate conical flask N-Phenyl-benzene-l,4-diamine (2.93 g, 0.016 mole) was dissolved in 25 mL of tetrahydrofuran and solution was transferred to a cylindrical runnel with pressure equalizing tube. Three-necked round-bottomed flask containing solution of 4-Bromomethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. N-Phenylbenzene- l,4-diamine solution was added drop-by-drop, from funnel to the flask in acidic medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final reaction mixture was allowed to attain room temperature. Product was separated by solvent evaporation. The product was purified using silica gel column chromatography. Product was identified by 'H-NMR. The yield of 2,6-di-te/f-butyl- 4-((4-phenylamino-phenylamino)-phenol is 2.044 g (63 %). Example 7: Synthesis of 2,6-di-tert-butyl-4-(4-isopropylaiiii]io-phenylamino)-methyl)- phenol 4-Bromomethyl-2,6-di-tert-butyl-phenol (2.42 g, 0.008 mole) was dissolved in 50 mL of dry tetrahydrofuran. In a separate conical flask N-Isopropyl-benzene-l,4-diamine (2.40 g, 0.016 mole) was dissolved hi 25 mL of tetrahydrofuran and solution was transferred to a cylindrical funnel with pressure equalizing tube. Three-necked round-bottomed flask? containing solution of 4-Bromomethyl-2,6-di-tert-butyl-phenol was kept in oil-bath at 85°C. Solution in the flask was continuously stirred with the help of magnetic stirrer. N-Isopropylbenzene- l,4-diamine solution was added drop-by-drop, from runnel to the flask in acidic medium for a span of 4-5 hours till all the solution was poured out. The reaction was terminated after that and the final reaction mixture was allowed to attain room temperature. The product was purified using silica gel column chromatography. Product was identified by 'H-NMR. The yield of 2,6-di-tert-butyl-4-[(4-isopropylamino-phenyIamino)-methyl]- phenol is 2.025 g (68 %). The process of the present invention has four distinct merits: 1) Bromination of hindered phenol does not involve use of any radical initiator or catalyst. 2) The process is economic and gives high yield (> 63 %) of product. 3) The process comprises of commonly available organic reagents and mild reaction conditions. 4) Reaction can be carried out via very facile route with very simple and moderate reaction conditions. We claim: 1 ,N,N-d(substituted para-phenylene diamines and a process for the preparation of compound of formula 1 below (Formula Removed) Which comprises dissolving a compound of formula 3 (Formula Removed) Wherein RI is tert-butyl,with bromine in a non-polar organic solvent at a temperature in the range of 80-95°C for a period of 4-7hrs,evaporating the solvent under reduced pressure to obtain a compound of formula 2. (Formula Removed) 2. A process for the preparation of novel antioxidant cum antiozonant of the formula 1 below (Figure Removed) which comprises dissolving a compound of formula 3 (Figure Removed) wherein RI is tert-butyl, with bromine in a non polar organic solvent at a temperature in the range of 80 to 95°C for a period of 4 to 7 hours, evaporating the solvent under reduced pressure to obtain a compound of formula 2 (Figure Removed) wherein R, is a tertiary butyl group and X is Br, reacting the compound of general Formula 2 with compound of formula 4 (Figure Removed) wherein R2 and R3 are C| to Cg linear or branched alkyl, in presence of an organic solvent using a mild base at a temperature in the range of 80 to 95 °C for a period of 4 to 7 hours, bringing the reaction mixture to room temperature, separating the organic layer and concentrating the product and purifying the final product of formula 1. 3. A process as claimed in claim 2 wherein the neutral organic solvent used for dissolving compound of formula 3 is a chlorinated solvent. 4. A process as claimed in claim 3 wherein the chlorinated solvent is selected the consisting of carbon tetrachloride, chloroform, chlorobenzene and dichloromethane. 5. A process as claimed in claim 2 wherein the bromination of compound of formula 3 i& done by liquid bromine. 6. A process as claimed in claim 2 wherein the para-phenylene diamine of formula 4 is selected from N,N-dimethyl-para-phenylene diamine, N,N-diethyl-para-phenylene diamine; 2,5-dimethyl-para-phenylene diamine and 2,5-diethyl-para-phenylene diamine. 7. A process as claimed in claim 2 wherein the solvent used to dissolve the para-phenylene diamine is tetrahydrofuran (THF). 8. A process as claimed in claim 2 wherein the mild base used to basify para-phenylentr diamine is selected from carbonates and bicarbonates of alkali metals. 9. A process as claimed in claim 8 wherein the carbonates and bicarbonates of alkali metals are selected from the group consisting of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate. 10. A process as claimed in claim 1 wherein the compound of formula 1 is concentrated by solvent evaporation under reduced pressure and purified by silica gel chromatography. 11. A antioxidant and antiozonant compound substantially as herein describe with reference examples accompanying this specification.

Documents:

248-DEL-2003-Abstract-(19-11-2008).pdf

248-del-2003-abstract.pdf

248-DEL-2003-Claims-(19-11-2008).pdf

248-del-2003-claims.pdf

248-DEL-2003-Correspondence-Others-(19-11-2008).pdf

248-del-2003-correspondence-others.pdf

248-del-2003-correspondence-po.pdf

248-DEL-2003-Description (Complete)-(19-11-2008).pdf

248-del-2003-description (complete).pdf

248-del-2003-form-1.pdf

248-del-2003-form-18.pdf

248-DEL-2003-Form-2-(19-11-2008).pdf

248-del-2003-form-2.pdf

248-DEL-2003-Form-3-(19-11-2008).pdf

248-del-2003-form-3.pdf

248-DEL-2003-Petition-137-(19-11-2008).pdf

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