Title of Invention	SUBSTITUTED BENZOTRIAZOLES AS UV-ABSORBER FOR PAINTS
Abstract	Abstract The present invention discloses Substituted benzotriazole UV absorbers of the formula (I) (I) Wherein R1-- an L akyl and alkylarvl and process tor preparation thereof. 1 3 FEB 2007

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FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION [See section 10, rule 13] "Substituted Benzotriazoles as UV-Absorber for Paints" (a) MALSHE VINOD CHINTAMANI (b) 1, Staff Quarters. UDCT Campus, Matunga Mumbai - 400 019. Maharashtra, India (c) Indian National 1 3 FEB 2007. The following specification particularly describes the nature of this invention and the manner in which It is to be performed: Technical Field of the Invention: The present invention relates to substituted benzotriazoles and its use as UV-absorbers in paints, polymers, plastic etc. This invention further relates to a process for preparation of substituted benzotriazoles. Background and Prior Art: Polymeric materials are gradually degraded when exposed to sunlight due to photo-oxidation reaction, leading to their short service life. In the photo-oxidation reaction when polymeric materials are exposed to UV rays, it leads to formation of free radicals on the polymer chain. These free radicals react with atmospheric oxygen and give peroxide which further decomposes to form carbonyl groups and chain scission. Irradiation in absence of oxygen causes the increase in crosslinking. This affects the mechanical properties and colour of the polymeric materials. To prevent or retard the photo-oxidation, stabilizers are added to the plastic. Stabilizers such as UV-absorbers, UV-stabilizers, light stabilizers etc. are employed to combat photo-oxidation in polymers. Among the various stabilizers, UV-absorbers, hindered amine light stabilizers (HALS) are outstandingly effective in extending the outdoor ageing life of polymers such as polyolefin, polyurethane, poly vinyl chloride in various applications like plastics, coatings. It is well known that HALS are the most effective light stabilizers on which extensive research and reviews have been published. UV-absorbers are the compounds, which upon addition to the polymers are capable of preventing or retarding the degradation reactions caused by light energy. Commercially 2-Hydrox\ phenyl benzotriazoles are one of the most important UV-absorbers. Hydroxyphenyl benzotriazoles monomers may be prepared by any method known in the art including those disclosed in US 5,104,992; US 4,943,637 and US 5,097,041. 2-AryI-2H-benzotriazoIes monomers may be prepared by reducing o-nitroazobenzenes through a 2-phenyibenzotriazoie-N-oxide intermediate. Reduction of o-nitroazobenzenes to 2-phenyibenzotriazoic by zinc in presence of sodium hydroxide is disclosed in U.S. Pat. Nos. 3,018,269; 3,773,751; 4,041,044 and 4,224,451. Aldehyde reducing agents and aromatic ketone catalysts are disclosed in U.S. 4,835,284. Different UV- absorbers are needed for stabilization of different systems; therefore novel UV-absorbers are very essential. UV-absorbers arc still widely used because of their low cost and effectiveness. There are five different types of UV-absorbers that have been used in industry, 2-phenyl benzotriazole deri\atives, especially those having lower alkyl substituents and also hydroxy substituents in the ortho position, on the phenyl moiety. US 4,315.848 describes the combination of the benzotriazole UV- absorber with a HALS which is efficacious in protecting thermoset and thermoplastic acrylic resin automotive finishes and enamels. More specifically benzotriazole described here is 2[2-hydroxy-3,5-di-(a, a-dimethyl benzyl)phenyl ]-2H benzotriazole which has good resistance for light induced deterioration, loss by volatilization on extrudation during high temperature processing of stabilized compositions. WO 9009369 discloses hydrazide functionalized benzotriazole and oxanilide UV light absorber for stabilized co-reactive or inert polymeric compositions and novel intermediates for the same. US 6,284.895 particularly describes bromo functionalized benzotriazole UV- absorber. US 6,353.113 discloses process for preparing 2H-benzotriazole UV- absorbers containing a perfluoroalkyl moiety at the 5l position of the benzo ring. Disclosed process comprises diazotization using concentrated sulfuric acid and sodium nitrite or preferably nitrosyl sulfuric acid and the diazonium salt is reduced by conventional reduction means. Patent published application US 2003/0,130,524 describes a novel one pot multiphase reaction for preparation of 2(2-nitrophenyl azo) substituted phenols, which are precursors for 2H-benzotriazole UV-absorbers. This present invention is aimed to prepare and evaluate 2-(5-Benzoyl-2H-benzotriazol-2yl)-4methyl phenol (PC), 2-(5-Benzoyl-2H-benzotriazol-2yl)-4,6-dimethyl phenol (XY) and 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol (BN) as UV-absorbers in paints. Summary of the Invention: The present invention discloses Substituted benzotriazole UV absorbers of the formula (I) (i) Wherein R= aryl, akyl and alkylaryl Substituted benzotriazole UV absorber of the formula (I) is 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol of formula (II). II Substituted benzotriazole UV absorber of the formula (I) is 2-(5-Benzoyl-2H-benzotriazol-2} l)-4-melhyl phenol of formula (III). III Substituted benzotriazole UV absorber of the formula (I) is 2-(5-Benzoyl-2H-benzotriazol-2yl)- 4,6-dimethyl phenol of formula (IV). IV Substituted benzotrizoles are used as UV absorbers in paints, polymers etc. Substituted benzotriazoles UV absorbers is used upto 5 % of the total composition. A process for preparation of the compound of formula II comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H:S04 at 0 to 5°C; coupling the resultant compound with p-naphthol in weak alkaline medium: reducing and cyclizing with Zn/NaOH to obtain 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol (BN). A process for preparation of the compound of formula III comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaNO2- H2SO4 at 0 to 5°C; coupling the resultant compound with p-cresol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain 2-(5-Benzoyl-2H-benzotriazol-2yl)- )-4-methyl phenol (PC). A process for preparation of the compound of formula IV comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H, with Nitrosyl sulfuric acid NaN02-M:S04 at 0 to 5°C; coupling the resultant compound with 2,6-xylenol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain 2-(5-Benzoyl-2H-benzotriazol-2yl)- )- 4.6-dimethyl phenol (PC). The invention further discloses the incorporation of these benzotriazoles in paints at different concentrations as UV-absorbers and evaluation for their stabilizing action and UV absorption. Detailed Description: The present invention relates to Substituted benzotriazole of the formula ([) as UV absorbers (I) Wherein R= aryl, akyl and alkylaryJ 6 Substituted benzotriazole UV absorber of the formula (I) is 2-(5-BenzoyI-2H-benzotriazol-2yl)-naphthol of formula (II). Substituted bcn/otriazole UV absorber of the formula (I) is 2-(5-Benzoyl-2H-benzotria/o!-2yl)-4-inelh\i phenol of formula (III). Ill Substituted benzotriazole UV absorber of the formula (I) is 2-(5-Benzoyl-2H-benzotriazol-2Y1)- 4.6-dimethyl phenol of formula (IV). Substituted benzotrizoies are used as UV absorbers in paints, polymers etc. Substituted benzotriazoles L'V absorbers is used upto 5 % of the total composition. A process for preparation of the compound of formula II comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H::SO.f at 0 to 5°C; coupling the resultant compound with p-naphthol in weak alkaline medium: reducing and cyclizing with Zn/NaOH to obtain 2-(5-Benzoyl-2H-benzotriazo(-2\i)-naphthoi (BN). A process for preparation of the compound of formula III comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H:S04 at 0 to 5°C; coupling the resultant compound with p-cresol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain 2-(5-Benzoyl-2H-benzotriazol-2yl)- )-4-methyl phenol (PC). A process for preparation of the compound of formula IV comprises diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosy] sulfuric acid NaN02-H2:S04 at 0 to 5°C; coupling the resultant compound with 2,6-xylenol in weak alkaline medium: reducing and cyclizing with Zn/NaOH to obtain 2-(5-BenzoyI-2H-benzotriazol-2yi)-)- 4,6-dimethyl phenol (PC). Substituted Benzotriazotes were synthesized from 4-amino-3~nitro benzophenone and couplers such as (3-Naphthol, p-Cresol and 2,6-xylenol. The reactions were monitored by TLC. The products were characterized by melting point, UV and IR-spectra. Stabilizing action of prepared 2-(5-Benzoyl-2H-benzotriazol-2yl)-4mehthyl phenol, 2-(5-Benzoyl-2H-benzotriazol-2vl)-4,6-dimethyl phenol and 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol for protecting paint against photo-oxidation was examined by QUV Weatherometer. The effect of exposure on the properties of paints such as gloss, whiteness and yellowness were evaluated. Results show that paints containing said substituted benzotriazoles as UV-absorbers possess better stabilizing effect against photo-oxidation than those employed in standard paints available in the market. Synthetic enamel white paint (without stabilizer) was used as Blank and Standard Paint (Ultra white paint with stabilizer) was used as standard (STD). Example 1 Synthesis of 2-( 5-Bcnzoyl-2H-benzotriazol-2ylVnaphthol (BN) 4-amino-3-nhro benzophenone (ANBP) was diazotized with (Nitrosyl sulfuric acid) NaN02 -H2SO4 mixture at 0 to 5°C and the resultant diazonium salt was coupled with p- naphthol in weak alkaline medium followed by reduction and cyclization with Zn / NaOH. The reaction was monitored by TLC and characterized by UV and IR. The yield of the prepared 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol (BN) was 70-80 %. Example 2 Synthesis of 2-(5-Bcazoy_l^H-benzotriazol-2vD- )-4-methyl phenol (PC) 8 4-arnino-3-niiro ben/ophenone (ANBPj was diazotized with (Nitrosyl sulfuric acid) NaN02 -H2SO4 mixture at 0 to 5CC and the resultant diazonium salt was coupled with p-cresol in weak alkaline medium followed by reduction and cyclization with Zn / NaOH. The reaction was monitored by TLC and characterized by UV and IR. The yield of the prepared 2-(5-Ben/.oyl-2H-benzotriazol-2yl)-4-methyl phenol (PC) was 70-80 %. Example 3 Synthesis of 2-(5-Benzovl-2H-benzotriazol-2yl)-)- 4,6-dimethyl phenol (PC) 4-amino-3-nitro ben/ophenone (ANBP) was diazotized with (Nitrosyl sulfuric acid) NaN02 -H2SO4 mixture at 0 to 5°C and the resultant diazonium salt was coupled with 2,6-xylenol in a weak alkaline medium followed by reduction and cyclization with Zn / NaOH. The reaction was monitored by TLC and characterized by UV and IR. The yield of the prepared 2-(5-Benzoyl-2H-benzotriazol-2yl)-4,6-dimethyl phenol (PC) was 70-80%. Analysis UV spectra were recorded using a UV spectrophotometer (Jasco V530). Water and Acetone mixture (8:2) was used as a solvent. IR spectra were recorded using an IR spectrophotometer (Buck IR Model 500). From the UV spectra (Figure No. 1, 2 and 3) of the products (BN. PC and XY) shows the UV absorption at 340nm and the complete cut off in the range at 293-190 nm, which represents the most harmful range of UV radiation for polymers. It is anticipated that this structure can effectively protect the paint coating against photo-oxidation by the mechanisms of screening action and rapid tautomerism. Testing for evalualion ufUV-absorbers The UV-absorbers so prepared were incorporated in the paint at different concentration such as 10. 100. 200 and 300 ppm and the paint was applied on the aluminium panels by brush. The gloss of the panels was measured at 45° and 60° angle of incidence (ISO 2813) using BYK. Glossometer. Whiteness and yellowness of the panels were determined by Gretag Macbeth make spectrometer CE7000 (optiview propalette 2.0e). In the assessment of ueatherability, the panels were exposed to the accelerated weather in QUV 9 apparatus (Model QUV/Basic). The panels were exposed to the cycle of UV light and humidity. In a typical cycle, exposure to UV light was at 45°C for 4 hours and exposure to humid conditions was at 45°C for 4 hours. The panels were subjected to ageing for 500 hours. The structures of the prepared compounds are as shown below Where, R= alkyl, aryl and alkylaryl From the I'Y-ubsorpiion spectra (Figure No.l, 2 and 3) of all the compounds show a complete cut off below 380 nm in water and acetone (8:2) as solvent at 250 ppm concentration. The most harmful wavelength range of UV is 200-330 (QUV C and QUV B). Total opaeii} in this range indicated a good possibility of these products acting as protective agents for coatings. Gloss Effect of UV-absorbers (10,100,200 and 300ppm level) on gloss at 45° angle The results are shown in figure No. 4, 5, 6 and 7. From the graph it is clearly seen that, before exposure the gloss of the standard panel was much higher than those panels containing prepared UV-absorbers and blank panels at all ppm levels. After 100 hrs exposure, the gloss of the blank panel was lower than the other panels containing UV absorbers & standard. After 200 hrs, the standard panel showed relatively higher drop in gloss at 100 ppm level. Where as after 200 hrs the gloss of the standard panel was lower than the others at all ppm level except 100 ppm. After 300 hrs, the gloss of the panels containing UV-absorbers did not change much as compared to blank and standard. Effect of UV-absorbers (10. 100, 200 and 300 ppm level) on gloss at 60° angle The data obtained is shown graphically in figure No. 8, 9, 10 and 11. From the graph it is clearly seen that, before exposure the gloss of the standard panel was higher than the other panels. After 100 hrs the gloss of the panels containing the standard, PC was higher than those of Blank XT and BN at all concentration levels except 10 ppm. After 200 to 500 hrs panels containing UV-absorbers show better gloss than Blank and standard. Yellowness and Whiteness Effect of UV-absorbers (at 10. 100, 200, 300 ppm) on Yellowness The results obtained are shown in figure No. 12, 13, 14 and 15. Before and after the exposure, yellowness of the panels containing UV-absorbers is lower than the standard and blank panels at all concentration levels while after 300, 400 and 500 hrs of exposure the yellowness of the Blank was much higher than the rest. Effect of UV-absorbers (at 10, 100, 200, 300 ppm) on Whiteness The data obtained is shown in figure No. 16. 17, 18 and 19. Before exposure the whiteness of the standard panel was lower than the others. At all concentration levels after exposure and before exposure the whiteness of the panels containing UV-absorbers was better than the others. Description of Drawings: Fig 1, 2, 3 are illustrated UV spectra for the products PC, BN and XY respectively. All figures show absorption at 340 nm and the complete cut off in the range of 293-190 nm which is most harmful range of UV radiation for polymers. This indicates that these products are very good protective agents for coatings. In all the figures, x-axis (numbers 2, 3 and 4) represents wavelength in nm against Y-axis (no. 2, 4 and 6) represents UV absorption. The UV-absorbers BN. PC and XY were prepared and incorporated in the paints at different concentration such as 10, 100, 200 and 300 ppm and the paint was applied on the aluminum panels. The gloss of the panels was measured at 45° and 60° angle of incidence using BYK glossometer. The results obtained for 10, 100, 200 and 300 ppm concentration of products UV-absorbers at 45° angle of incidence are shown in Figures 4, 5, 6 and 7. In all the tour figures X-axis (7, 14, 21 and 28) represents the exposure time in hours against Y-axis (K, 5, 22 and 29) which represents gloss of the panels. Before the exposures the gloss of standard panels was much higher than the panels containing UV-absorbers and blank. After 200 hour exposures the standard panel showed relatively higher drop in gloss at 100 ppm levels. Whereas after 200 hours the gloss of the standard panel was lower than the others at all ppm level except 100 ppm. After 300 hours, the gloss of the panels containing UV-absorber did not change much as compared to blank and standard. Numbers 9. 16, 23, 30 represent results obtained for standard UV-absorber and no. 10. 17. 24. 31 is for blank sample at 10, 100, 200 and 300 concentration. Gloss measured for BN absorber is measured at 45° angle of incidence and represented by numbers 11. 18. 25 and 31 at 10, 100, 200, 300 ppm concentration respectively. Similarly Numbers 12. 19. 26 and 32 represent gloss measured for PC and no. 13, 20, 27 and 33 are for XY at 10. 100. 200 and 300 ppm concentration respectively. The gloss obtained at 60° angle of incidence for different concentration of UV-absorbers is shown graphically in figures 8, 9. 10 and 11. From the graph it is clearly seen that, before exposure the gloss of the standard panel was higher than the other panels. After lOOhrs the gloss of the panels containing the standard, PC, was higher than those of Blank, XY and BN at all concentration levels except lOppm. After 200 to500 hours, panels containing I'V-absorbers showed better gloss than Blank and standard. In all the four figures X-axis (25, 43. 49 and 57) represents the exposure time in hours against Y-axis (36, 44. 50 and 56) which represents gloss of the panels. Numbers 37, 44, 51, and 58 represent results obtained for standard UV-absorber and nos. 38, 45, 51, 58 are for blank sample at 10. 100. 200 and 300 concentration. Gloss measured for BN absorber is measured at 60' angle of incidence and represented by numbers 39, 46, 52 and 59 at 10, 100, 200. 300 ppm concentration respectively. Similarly Numbers 40, 47, 53 and 60 represent gloss measured for PC and no. 41, 48, 54 and 61 are for XY at 10, 100, 200 and 300 ppm concentration respectively. Effect of UV-absorbers at different concentrations, 10, 100, 200 and 300 ppm on Yellowness of the panels is measured and has been shown in figure No. 12, 13, 14 and 15. . In all the four figures X-axis (64, 71, 77, 84) represents the exposure time in hours against Y-axis (63. 70, 78 and 85) which represents yellowness of the panels. Numbers 65, 72, 79 and 86 represent results obtained for standard UV-absorber and no. 66, 73, 80, 87 is for blank sample at 10. 100, 200 and 300 concentrations. Yellowness measured for BN absorber is measured and represented by numbers 67, 74, 81 and 88 at 10, 100, 200, 300 ppm concentration respectively. Similarly numbers 68, 75, 82 and 89 represent yellowness measured for PC and no. 69, 76, 83 and 90 are for XY at 10, 100, 200 and 300 ppm concentration respectively. Before and after the exposure, yellowness of the panels containing UV-absorber was lower than the standard and blank panels at all concentration le\e)s while after 300,400 and 500 hrs of exposure the yellowness of the Blank was much higher than the rest. Effect of UV-absorbers at different concentrations, 10, 100, 200, 300 ppm on Whiteness of the panels is shown in figure No. 16, 17, 18 and 19. In all the four figures X-axis (91, 98, 105. 112} represents the exposure time in hours against Y-axis (92, 99, 106 and 113) which is represents whiteness of the panels. Numbers 93, 100, 107 and 114 represent results obtained for standard UV-absorber and no. 94, 101, 108, 115 are for blank sample at 10, 100. 200 and 300 concentrations. Whiteness measured for BN absorber is measured and represented by numbers 95, 102, 109 and 116 at 10, 100, 200, 300 ppm concentration respectively. Similariy Numbers 96, 103, 110 and 117 represent whiteness measured for PC and no. 97, 104, 111 and 118 are for XY at 10, 100, 200 and 300 ppm concentration respectively. Before exposure the whiteness of the standard panel was lower than the others. At all concentration levels after exposure and before exposure the whiteness of the panels containing UV-absorber was better than the others. Prepared benzotriazole based UV-absorbers showed higher initial whiteness than standard stabilizer. As compared to standard stabilizers prepared UV-absorbers showed an increase in >ellowness initially. The protective ability of prepared UV-absorber is retained even after 200 hrs whereas the standard stabilizer failed. Gloss values of the paints did not show any particular trend but the values at 45° angle remained constant after 300hrs at all concentrations. We claim, 1. Substituted benzotriazole compounds of the formula (I) used as UV absorbers in paints and polymers Wherein R= aryl, akyl and alkylaryl. 2. Substituted benzotriazole UV absorber of formula (I) according to claim 1, is 2-(5-Benzoyl-2H-benzotriazol-2yl)-naphthol. II 3. Substituted benzotriazole UV absorber of formula (I) according to claim 1 is 2-(5-Benzoyl-2H-benzotriazol-2yl)-4-methyl phenol. III 4. Substituted benzotriazole UV absorber of formula (I) according to claim 1 is 2-(5-Benzoyl-2H-benzotriazol-2yl)- 4,6-dimethyl phenol. 5. Substituted benzotriazole UV absorber of formula (I) according to claims 1 to 4, wherein said compounds can be used upto 5% of the total composition of the paints or polymers. 6. A process for preparation of the compound of formula (I) as claimed in claim 2, wherein said process comprises; diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H2S04 at 0-5°C; coupling the resultant compound with (3- naphthol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain substituted benzotriazole (BN). 7. A process for preparation of the compound of formula (I) as claimed in claim 2, wherein said process comprises; diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H2S04 at 0-5°C; coupling the resultant compound with p-cresol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain substituted benzotriazole (PC). 8. A process for preparation of the compound of formula (I) as claimed in claim 2, wherein said process comprises; diazotizing 4-amino-3-nitro benzophenone (ANBP) of formula I, wherein R=H; with Nitrosyl sulfuric acid NaN02-H2S04 at 0-5°C; coupling the resultant compound with 2,6-xylenol in weak alkaline medium; reducing and cyclizing with Zn/NaOH to obtain substituted benzotriazole (PC). 9. Substituted benzotriazole UV absorbers as substantially described herein with reference to the foregoing examples 1 to 3. Dr. Gopakumar G. Nair Agent for the applicant Dated this the 29th day of Oct 2004

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