ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Spectrophotometric determination of the dissociation constants of derivatives of 2-hydroxybenzophenone and 2,2'-dihydroxybenzophenone

P.Hrdlovič and D. Belluš

Institute of Polymers, Slovak Academy of Sciences, Bratislava 9

Abstract: Uv absorption spectra and spectrophotometric titrns. were applied in the measurement of the dissocn. consts. pK' of the derivs. of 2-hydroxybenzophenone (I) and 2,2'-dihydroxybenzophenone (II). From the measured pK' values, the difference of the energy between the intramol. and intermol. H bond of I and II, 2 kcal./mole, was calcd. The pK' values were detd. on the following benzophenene derivs. (substituents and m.p. given): 4-hydroxy, 135°; 2-hydroxy, 37°; 2-hydroxy-4-methoxy, 61°; 2,2'-dihydroxy-4-methoxy, 70°; 2,2'-dihydroxy-4,4'-dimethoxy, 133-6°; 2-hydroxy-4-(β-hydroxyethoxy), 89-90°; 2-hydroxy-4,4'-bis(β-hydroxyethoxy), 128°; and 2,2'-dihydroxy-4,4'-bis(β-hydroxyethoxy), 152°. In the II derivs., a decreased stability of the H bond was detd., which indicates an increased reactivity of an OH group in the positions 2 and 2' as compared with the reactivity of the OH group in derivs. of I during esterification and etherification reactions.

Full paper in Portable Document Format: 216a410.pdf (in Slovak)

Chemical Papers 21 (6) 410–416 (1967)