Studies on Synthesis and Dyeing Preformance of Acid Dyes Based on 4 , 7-Dihydroxy-1 , 10-Phenanthroline-2 , 9-Dione

Some new azo acid dyes were prepared by coupling various diazotized acid components such as anthranilic acid, sulphanilic acid, laurent acid, peri acid, tobias acid, H-acid, J-acid, gamma acid, sulphotobias acid, 4-aminotoluiene-3sulphonic acid, 5-sulphoanthranilic acid, 2-naphthylamine-3,6,8-trisulphonic acid, bronner acid, metanilic acid and cleve acid with 4,7-dihydroxy-1,10phenanthroline-2,9-dione. The dyes were characterized by elemental, IR and TLC analyses. Their dyeing performance as acid dyes has been assessed on viscose rayon, wool and cotton fibres.


Introduction
The newest additions of existing acid dyes are the centre of attraction in dyestuff research 1 .Various dyes based on quinazoline, quinoline and 4-oxo-quinazoline ring system have been reported to be useful on natural and man-made fibres, showed high affinity and good dyeing performance [2][3][4] .Some of them also showed potential biological activity.Therefore it was thought interesting to study the synthesis, characterization and dyeing performance of various acid dyes based on 4,7-dihydroxy-1,10-phenanthroline-2,9dione heterocyclic ring system.

Experimental
Melting points were determined in open capillaries and are uncorrected.The IR spectra (KBr) were recorded on a Perkin-Elmer spectrophotometer (Model 377).UV-Visible spectra were recorded on Backman DB-GT grating spectrophotometer using 1x10 -3 M aqueous solution.TLC was carried out on Silica gel-G as absorbent using reported procedure 5 .

Synthesis of 4,7-dihydroxy-1,10-phenanthroline-2,9-dione (A)
A solution of o-phenylenediamine (0.1 mole, 10.80 g) in diethyl malonate (0.22 mole, 13.930 mL) was added portion wise to poly phosphoric acid (prepared from 38.6 g P 2 O 5 and 21.4 mL of orthophosphoric acid).The deep green pasty mass obtained was heated at 170°C for 30 minutes.The reaction mixture was left to cool and poured into cold water.The solution obtained was neutralized with 5% NaOH solution.The product obtained was filtered, dried and crystallized.m.p. 315°C, yield 75%.

Coupling of diazotized acid component with (A)
The coupling component (0.01 mole, 5.32 g.) was suspended in NaOH (10%, 15 mL) and the pH of the solution is maintained neutral with sodium carbonate solution (10% w/v) to obtain a clear solution.The solution was cooled to 0-5°C and the cooled diazo solution of acid component (0.01 mole) was added drop wise with stirring, maintaining the pH to 8.0 by simultaneous addition of sodium carbonate (10 % w/v).Stirring was continued for 2 hours at 0-5°C.The reaction mixture was heated to 60°C after 2h and sodium chloride was added till the dyestuff is precipitated out.After stirring for an hour the liquor was filtered and the product was washed with a small amount of 5% sodium chloride solution.The dye was dried at 90°C.It was then purified by extraction with DMF and precipitation by diluting the DMF extract with acetone.

Dyeing of fibres
All the dyes D 1 to D 15 were applied on viscose rayon, wool and cotton fibres in 2% shade by using the reported procedure 6 .

Fastness test
Fastness to the light was assessed in accordance with BS:1006-1978 and the wash fastness was assessed in accordance with IS:765-1979.
All the dyes D 1 to D 15 were applied to viscose rayon, wool and cotton fibres gave violet, blue, green, yellow, orange brown and maroon shades.D 7 , D 8 , D 11 , D 14 , D 15 gives deeper shades on all three fibres.Most of the dyes give green shades.The % exhaustion and  2 indicates good affinity for all the fibres used in study.The pick-up values of these dyes varied from 2 to 4. The light fastness varied from poor to fairly good whereas fastness to washing varied from fair to excellent.Exhaustion ranges from 63.75% to 74.50%.
dyes D 1 to D 15 are given in Table

Table 1 .
Physical data for acid dyes

Table 2 .
% Exhaustion, Light fastness and Wash fastness data