Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 2(11), 14-19, November (2012) Res.J.Chem. Sci. International Science Congress Association 14 Microwave Assists the Synthesis of Pyridone azo Dyes and their Application in Polyester Printing Ahmed K.A., Elhennawy H.M.and Elkashouti M.A. Chemistry of Dyeing, Printing and Auxiliaries Department, Textile Division, National Research Center, Cairo, EGYPT Available online at: www.isca.in Received 20th June 2012, revised 28th June 2012, accepted 11th July 2012Abstract In this study microwave assists synthesis of new class arylazopyridone dyes, where these dyes synthesized from corresponding dianalides, which coupled with some diazotized aromatic amines to give azodisperse dye which react with cyanoacetamide to form crossponding derivatives of pyridone azo dyes . the structure of these dyes were confirmed by IR, H-NMR, Mass spectra and element analysis. The fastness properties of silk screen printed polyester using these synthesized dyes have been investigated. The prints possess very good fastness properties of washing, rubbing, perspiration and light fastness. Keywords: Microwave, pyridone azo dyes, textile printing. IntroductionA microwave is a form of electromagnetic energy, which falls at the lower end of the electromagnetic spectrum and is defined in a measurement of frequency as 300 to 300,000 Megahertz, corresponding to wavelengths of 1 cm to 1 m1. The microwave region of the electromagnetic spectrum lies between infrared and radio frequencies 2, 3. Wavelengths between 1 cm and 25 cm are extensively used for RADAR missions and remaining wavelength range is used for telecommunications. In order to avoid interference with radar and telecommunication activities, which also operate in this region, most commercial and domestic microwave ovens operate at 2450 MHz (12.25cm). The difference between microwave energy and other forms of radiation, such as X- and -rays, is that microwave energy is non-ionizing and therefore does not alter the molecular structure of the compounds being heated – it provides only thermal activation. The heating effect utilized in microwave assisted organic transformations is mainly due to dielectric polarization. When a molecule is irradiated with microwaves, it aligns itself with the applied field. The rapidly changing electric field (2.45 x 109 Hz) affects the molecule and consequently the molecule continually attempts to align itself with the changing field and energy is absorbed. The ability of a material to convert electromagnetic energy into thermal energy is dependent on the dielectric constant. The larger the dielectric constant the greater is the coupling with microwaves. Thus, solvents such as water, methanol, DMF, ethyl acetate, acetone, acetic acid, etc. are all heated rapidly when irradiated with microwaves. However, solvents with low dielectric constants such as hexane, toluene, carbon tetrachloride, etc. do not couple and therefore do not heat that rapidly under microwave irradiation. Microwave heating has thus been found to be a very convenient thermal source not only in the kitchen but also in a chemical laboratory. Chemists have explored the possibility of the application of a conventional microwave oven to carry out chemical reactions. It has been found that many reactions progress much faster upon microwave irradiation than with traditional heating techniques. The application of microwave irradiation to activate and accelerate organic reactions has taken a new dimension and has experienced exponential growth in the last ten years 2-8. Microwave chemistry is becoming increasingly popular both in industry and in academia1, 9-13. We hope to demonstrate in this article the utility of this technique, to prepare new class of pyridone azo dyes and studying their printing properties. Material and MethodsMaterials: The following materials were employed in the study reported here. Fabric: Polyester (PE) knitted fabric of 150g/msupplied by a private sector company, was treated with a solution containing 1g/l non-ionic detergent at 70 C for 1/2 h., thoroughly washed, and air dried at room temperature. Thickener: Commercial synthetic thickener (Lecuo print) supplied by BASF Company. Chemicals: 2,4-dimethoxyaniline, 4- methoxyaniline, 4-methylaniline, p-chloroaniline, p-nitroaniline, o-chloro-p-nitroaniline, p-Bromoaniline, 2,4-dichloroaniline, sodium acetate, ethanol, sodium ethoxide, cyanoacetamide, diethylmalonate, hydrochloric acid. All chemical used were in Reagent Grades. Synthesis: Synthesis of 4-chlorophenylmalonamide General procedure for Microwave irradiation:4-chloroaniline (10mmol), diethylmalonate (5mmol) were probably mixed in 25ml beaker, the obtained mixture was irradiated in microwave Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(11), 14-19, November (2012) Res. J. Chem. Sci. International Science Congress Association 15 oven (MICRO-CHEF FM 3935QT) at the power of 1500 w for 2 min., after the irradiation, the crude product was re-crystallized in ethanol . General procedure for Conventional heating: Mixture of 4-chloroaniline(10mmol), diethylmalonate (5mmol)were refluxed for 4h. and then allowed to cool room temperature. The resulting solid product was collected by filtration. The crude product was re-crystallized in ethanol Synthesis of 5-arylazo3-cyano-4,6-dianalinopyridine2(1)one derivatives: General procedure for Conventional heating: A mixture of arylazo 4-chlorophenylmalonamide (1,3-dianilino-1,3-propanedione) (0.01mole) and cyanoacetamide (0.01 mole) were dissolved in ethanol (30ml)containing sodium ethoxide (0.01 mole). The mixture was refluxed for 4 h and then allowed to cool room temperature and acidified with dilute hydrochloric acid. The resulting solid product was collected by filtration and crystallized from the ethanol. General procedure for Microwave irradiation: A mixture of arylazo 4-chlorophenylmalonamide (1,3-dianilino-1,3propanedione) (0.01mole) and cyanoacetamide (0.01 mole) were dissolved in ethanol (30ml)containing sodium ethoxide (0.01 mole). The mixture was irradiated in microwave oven at the power of 1500 w for 5 min., and then allowed to cool room temperature and acidified with dilute hydrochloric acid. The resulting solid product was collected by filtration and crystallized from the ethanol scheme 1. Printing experiment: Lab scale printing experiments were carried out on polyester fabric using the produced dyes. The printing paste 100 gm. consists of 3gm. of sodium alginate as thickener, 3 g. of prepared dye and 96 ml of water. Samples of polyester fabric were silk screen printed using the above printing paste, the printed fabric was dried and fixed at different temperatures 150, 170, 190 and 210C , fixation time 2 and 3 min. respectively, then washed twice by cold water, then twice with hot water and finally rinsed with cold water, then air dried. Measurements: Melting point: All melting points of the synthesized dyes were determined in open glass capillaries on gallenkamp melting point apparatus and are uncorrected. Spectroscopic analyses: The infrared of the synthesized dyes was measured by a Perkin Elmer/1650.FT-IR instrument The H – NMR spectra were measured in a varian 400 or wilmad 270 MHZ spectrometer for (CD3) SO solutions using SiMe4 as internal standard. Mass spectra were measured on a Varian MAT CH-5 spectrometer (70 eV). Mass spectra were recorded on a Varian MAT112 spectrometer. Analytical data was obtained from the micro analytical data centre at Cairo University. Spectrophotometric measurements: The absorbance of the dyes was measured in the ultraviolet-visible region between 300-700 nm by a UNICAM UV spectrophotometer using a 1cm. quartz cell. The dyes were dissolved in absolute ethanol at a concentration of 10-4 mole/l. Scheme-1 Structure of synthesized compounds Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(11), 14-19, November (2012) Res. J. Chem. Sci. International Science Congress Association 16 Colour strengthmeasurements: The reflectance values of the fabric were measured using a Data Colour SF 600+. Relative colour strengths (K/S values) were determined using the Kubelka-Munk equation14,15. K/S = (1-R) 2 /2RFastness properties measurements: Fastness to washing, rubbing, light and perspiration were assessed according to standard methods16-18. Results and Discussion4-chlorophenylmalonamide was prepared by refluxing 4-chloroaniline (10mmol), diethylmalonate (5mmol) for 4h and 5-arylazo3-cyano-4,6-bis(4chlorophenyl)aminopyridine-2(1)one derivatives were prepared by refluxing substituted arylazo4-chloromalonamide with cyanoactamide in the presence of sodium ethoxide in ethanol. The same reactions could be carried out under microwave conditions. It is noteworthy that the reaction which required 4h in conventional method was completed efficiently, with high yield 85%in 2-5 min under microwave conditions table 1. Therefore, microwave procedure could offer an efficient pathway to synthesis 4-chlorophenylmalonamide and 5-arylazo3-cyano-4,6-dianalinopyridine-2(1)one derivatives. The microwave technique has been employed to reduce the reaction time, rate enhancement and increase the selectivity and yield. All the synthesized compounds have been characterized on basis of their element analysis and spectral data (MS, 1H NMR IR,). The analytical data for 4a revealed a molecular formula 2518 ClSO (M = 498) , H NMR exhibited abroad peak at 11.35(1H, OH), multiple at 6.5-7.79 for aromatic, The IR spectra showed strong broad absorption band at 3500-3150 cm-1 for the hydroxyl (OH) and amide group (NH) and strong sharp band at 2219cm-1(CN) group table 2 and 3. The effect of the structural configuration on the UV-visible absorption maxima of the synthesised dyes: The electronic absorption spectra of the synthesised dyes have been studied. Thus the UV spectra of 5-arylazo3-cyano-4,6-bis(4chlorophenyl)aminopyridine-2(1)onederivatives lie in the range 395 – 480 nm table 4. These dyes have two tautomeric formula (enol form) I and (keto form) II . Tautomer I has two resonating structures A and B, scheme 2. Optimum conjugation is observed in the resonating system B, where the lone pair electron of the (OH) group interacts efficiently with arylazo moiety. Consequently, such a high energy dipolar arrangement will be stabilised when X is an electron- withdrawing group. cyano group in the third position had no shift in absorption. The bathochromic shift is observed in case of dye 4h and this may be attributed to its molecular structure which possess electron two withdrawing groups (Cl and NO groups) . Colour characteristics of printed polyester: The colour characteristics of printed polyester were investigated and are shown in table (4). It is clear from the table that the colour characteristics of the printed polyester fabric (which expressed as K/S) varied due to difference in the nature of substituents attached to arylazo moity of the dye molecules., for ex dye no. possess high colour strength and this may be attributed to presence of two electron withdrawing groups (Cl, NO). The printed polyester samples using the prepared dyes 4a-h were thermo fixed at different temperatures 150, 170, 190 and 210 C, the fixation time is two and three minutesfigures, 1 and 2. The fixation temperature play an important role on the colour strength It is shown from figure 1and 2 that as the fixation temperature increase the colour strength increase over all the dyes. The fixation time 3 min. has no significant effect on the colour strength value. Table-1 Comparison between Reaction time, Yield % of the synthesized dyes 4a –h using Microwave and Convention heating Dye No. Ar Reaction time Yield % Microwave /min Convention heating microwave Convention heating 4a CH 3 min 4h. 65 82 4b 3 min 4h. 67 80 4c 4 min 5h. 58 80 4d 4 min 4h. 60 85 4e 4 min 4h. 65 85 4f 4 4 66 82 4g 5 5 55 82 4h 5 5 62 85 OMe OMe OMe Cl Br NO ClCl NOCl Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(11), 14-19, November (2012) Res. J. Chem. Sci. International Science Congress Association 17 Table-2 Physical and analytical data of synthesized dyes 4a –hCompound No.Colour Yield % m.p C Molecular FormulaMolecular weightmaxFT-IR (KBr, Cm-1Element analysis Required (%) Found (%) NH, OH CN C H N O C H N O yellow 84 287 C2518ClO 498 395 3150-3500 2219 61.36 3.71 17.17 3.27 61.09 3.44 17.15 3.11 yellow 89 257 C2518Cl 505 416 3150-3500 2216 59.42 3.59 16.63 6.33 59.33 3.40 16.50 6.10 orange 85 252 C2620Cl 535 422 3150-3500 2217 58.33 3.77 15. 7 8.97 58.11 3.61 15.51 8.81 yellow 89 292 C2415ClO 509 430 3150-3500 2217 56.55 2.97 16.49 3.14 56.48 2.88 16.35 3.10 orange 88 253 C2415BrClO 554 444 3150-3500 2220 52.97 2.59 15.16 2.89 52.11 2.47 15.09 2.51 brown 87 269 C2415Cl 520 460 3150-3500 2216 55.4 2.91 18.84 9.22 55.32 2.85 18.81 2.88 brown 85 285 C2414ClO 544 472 3150-3500 2217 52.97 2.59 15.44 2.94 52.88 2.49 15.41 2.88 Brown 91 277 C2414ClN 554 480 3150-3500 2216 51.96 2.54 17.67 8.65 51.45 2.44 17.50 8.59 Table-3 H-NMR and mass spectra of the synthesized dyes 4a-h MS (M +1 ) 1 H-NMR (ppm.) Compound no. 488 2.34 (s, 3H, CH3), 6.5-8.79(m, 12H, 3 C6H4,), 4 (s, 2H, 2NH), 11.53 (s, 1H, OH). 4a 504 2.5 (s, 3H, OCH3), 7.1-8.3 (m, 12H, 3 C6H5), 4 (s, 2H, 2NH), 11.4(s,1H, OH). 4b 534 3.83 (s, 6H, 2OCH3), 6.88-7.77 (m, 11H, 2 C6H4, C6H3), 4.2 (s,2H, 2NH), 11.8 (s, 1H, OH). 4c 508 6.6-7.78 (m, 12H, 3 C6H4), 4 (s, 2H, 2NH), 11.7 (s, 1H, OH). 4d 553 7.0-8.2 (m, 12H, 3C6H4,), 4.4 (s, 2H, 2NH), 11.53 (s, 1H, SH). 4e 519 7.2-8.2(m, 12H, 3C6H4,), 4.2 (s, 2H, 2NH), 11.52 (s, 1H, OH). 4f 542 7.24-8.78(m, 11H, 2C6H4, C6H3), 4.0 (s, 2H, 2NH), 11.54 (s, 1H, OH). 4g 553 7.24-8.35(m, 11H, 2C6H4, C6H3), 4.1 (s, 2H, 2NH), 11.61 (s, 1H, OH). 4h Table-4 Colour strength and fastness properties of Screen printed *polyesterfabric, using the synthesized dyes (4a-h) Light fastness Perspiration Rubbing Washing K/S Dye No. Alkali Acidic St. Alt. St. Alt. wet dry St. Alt. 5 5 4 4 5 4 4 4 4 8.5 4a 5 4-5 4-5 4 5 4 4 4 4 8 4b 5 5 4 5 5 4 4 4 4 7.5 4c 5 4-5 5 4 5 4 4 4 4 7.4 4d 5-6 5 5 5 5 4-5 5- 4 4 7 4e 5-6 5 4 5 5 4 4 4 4 8.2 4f 6 4-5 5 4-5 5 4 4 4 4 11 4g 6-7 5 5 5 5 4-5 4-5 4 4 11.2 4h Research Journal of Chemical Sciences ____ _ Vol. 2(11), 14-19, November (2012) International Science Congress Association N OH N N N X Cl CN N Cl H H X N OH N N N X Cl CN N Cl H H N OH N N N X Cl CN N Cl H H X Scheme- 2 Resonating structure of synthesized compounds Figure-1Effect of fixation temperature on the colour strength of silk screen printed poly ester using synthesized dyes 4 time 2 min. Fastness properties: Table 4 showed the fastness properties of screen printed polyester. Wash fastness: The rate of movement of dye out during washing depends on the molecular size of the dye molecules, the type of the linkage between the dye and the fibre and charge located on the dye which in turn, depends the electron donating and electron withdrawing character of the substituents19, 20 . The result of wash fastness for printed polyester fabric at 190 C was 4- 5 for most dyes. _ _____________________________________________ _ Association N O H N N N Cl CN N Cl H H N O H N N N Cl CN N Cl H H II synthesized compounds temperature on the colour strength of silk screen printed poly ester using synthesized dyes 4 , fixation Table 4 showed the fastness properties of The rate of movement of dye out of the fibre during washing depends on the molecular size of the dye molecules, the type of the linkage between the dye and the fibre and charge located on the dye which in turn, depends the electron donating and electron withdrawing character of the . The result of wash fastness for printed 5 for most dyes. Figure - Effect of fixation temperature on the colour strength of silk screen printed poly ester using synthesized dyes 4 fixation time 3 min Perspiration fastness: The magnitude of the dye removal from polyester fabric of perspiration solutions (alkali and acidic) are shown. The result indicates that the dye removal could be dependent on the molecular weight of the dye and the binding forces between the dye and the fibre. Thus dye 4 having higher molecular weight compared to other synthesized dyes, had higher fastness in perspiration solution. Rub-fastness: A numerical measure for the removal of loosely adhered dye molecules from the fibre surface was achieved through the rubbing test method. The data obtained show higher values of rubbing fastness for dyes of higher molecular weights. Thus dye 4e and 4h have rubbing fastness between 4 and 5 Light fastness: Some studies have sho dyes are generally more light fast than their counterparts, the light fastness of these dyes arises from their ability to undergo intramolecular proton transfer form OH group to adjacent C=O group following light absorption in the U internal conversion process, as the absorbed UV light energy is dissipated as harmless heat. Small no. of light fast azo disperse dyes take advantage of inter molecular hydrogen bond between the azo (N=N) group and adjacent (NH) group to dye against UV light degradation, so the good light fastness of our prepared dyes may be arise from their ability to undergo interamolecular hydrogen bond between the azo (N=N) group and adjacent (NH) group 21. ConclusionNew derivatives of bis(4chlorophenyl)aminopyridine- 2(1 using assistance of microwave technique to reduce the reaction time and produce a good yield. The sturcture of substituted 5 arylazopyridine-2(1 )one dyes were established and _ ________ ISSN 2231-606X Res. J. Chem. Sci. 18 - 2 Effect of fixation temperature on the colour strength of silk screen printed poly ester using synthesized dyes 4 a-h , fixation time 3 min The magnitude of the dye removal from polyester fabric of perspiration solutions (alkali and acidic) are shown. The result indicates that the dye removal could be dependent on the molecular weight of the dye and the binding between the dye and the fibre. Thus dye 4 e, and 4h having higher molecular weight compared to other synthesized dyes, had higher fastness in perspiration solution. A numerical measure for the removal of loosely the fibre surface was achieved through the rubbing test method. The data obtained show higher values of rubbing fastness for dyes of higher molecular weights. have rubbing fastness between 4 and 5 Some studies have sho wed that, anthraquinone dyes are generally more light fast than their counterparts, the light fastness of these dyes arises from their ability to undergo intramolecular proton transfer form OH group to adjacent C=O group following light absorption in the U V region . This is internal conversion process, as the absorbed UV light energy is dissipated as harmless heat. Small no. of light fast azo disperse dyes take advantage of inter molecular hydrogen bond between the azo (N=N) group and adjacent (NH) group to stabilize the dye against UV light degradation, so the good light fastness of our prepared dyes may be arise from their ability to undergo interamolecular hydrogen bond between the azo (N=N) group 5-arylazo3-cyano-4,6- 2(1 )one were synthesized assistance of microwave technique to reduce the reaction time and produce a good yield. The sturcture of substituted 5 - )one dyes were established and confirm Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 2(11), 14-19, November (2012) Res. J. Chem. Sci. International Science Congress Association 19 for the reaction products on the basis of their element analysis and IR, H-NMR and mass spectra spectra. The substituents on the arylazo moiety of the synthesized dyes have a considerable effect on the colour strength value. This depends on the electron mobility through the resonating system, which in turn depends on the type of the substituent. The printing characteristics of prepared dyes system 4a-h on polyester fabric have good colour strength, good washing, rubbing, perspiration and light fastness. AcknowledgementThis work was supported by National Research centre, textile division, dyeing, printing and auxiliaries department References1.Ravichandran S. and Karthikeyan E., Microwave Synthesis - A Potential Tool for Green Chemistry, Int.J. ChemTech Res., 3(1), 466-470 (2011)2.Ricardo A. Tapia, Lorena C.,Mauricio C.,and Joan V.,Microwave-Assisted Reaction of 2,3-Dichloronaphthoquinone with Aminopyridines, J. Braz. Chem. 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