Spectral Study on the Alkaline Hydrolysis of Some 4-Aminoazobenzene Dyes Bearing a -OH, -OCOR, -OCOOR or -COOR Residue in N- alkyl Group

알킬아미노기 말단에 -OH, -OCOR, -OCOOR, -COOR 등의 치환기를 갖는 4-아미노아조벤젠계 염료의 알칼리 가수분해에 대한 분광학적 고찰

Spectral changes In alkaline hydrolysis of some 4-amlno azobenzene dyes hearing a -OH, -OCOR, -OCOOR or -COOR residue in coupler's N-alkyl group were investigated. The dye containing -OH group showed only a slow hypsochromic shift without a hypochromic shift in solution, and the uptake of the hydrolyzed species on poly(ethylene terephthalate) (PET) did not decreased significantly. The 4'- vitro azobenzene dye containing - OCOR group showed a bathochromic shift with a slight hypochromic shift in solution, and its dye uptakes on PET decreased repidly. Two 2'- bromo-4', 6'-dinitroazobenzene dyes containing -OCOR or - OCOOR group had marked reductions of original dye concentration in solutions and their dye uptakes on PET also decreased by short time hydrolysis. The dye possessing - COOR group showed a bathochromic shift with a hyperchromic shift in solution, but became undyeable rapidly. These results may be caused by the alkaline hydrolysis of -OH, -OCOR, -OCOOR and -COOR residues in coupler's N -alkyl groups, by the steric hindrance and changes of electron density resulted from the hydrolysis of four o -and m - substituents and by a certain cleavage.