Tho absorption spectra of 4-hydroxybenzthlazolc and the parent compound, benzthlarole, have been dctcrmmcd In acrdlc, basic and neutral solutions, and compared with the correspond-Ing absorption spectra of 8-hydroxyqulnohnc and qurnolmc The dlssoclatlon constants of 4-hy-tlroxybcntthlaLolc obtamcd by a epcctrophotomctrtc mcthotl as well a~ a potentiomctrlc method, show that It 1s a stronger acid and a wcakcr base than 8-hydroxyqulnollne I.es spcctrcs d'abeorptlon clu q-hyclroxybenzothlazolc ct du composd volsln, IO benzothiazolc, ont , btb cldtcrmlnds cn eolutlons acldc. baslquc ct ncutrc, ct compards avcc lcs spcctrcs tl'absorptlon corrqrpondants do la S-hydroxyqulnol6mc ct dc la qulnol&nc Les constantcs clc dlssocratton dc 4-hydroxybcntothlaLolc obtcnucs par mCthodc spcctrophotombtrlquc aus blcn quc par mdthodc potcntlombtrrquc. montrcnt quc c'cst un aadc plus fort, ct uno base plus falblc qua la d-hydroxyqulnolblnc ZUSAMMENFASSUNG DIG Absorptlonespcktrcn dcs q-Oxybcnzthlazols und dcs vcrwandton bcnzthmzols wurdcn In qaurcr, baslschcr und ncutralcr L6sung bestlmmt und mlt den ontsprcchcndcn Spcktrcn dcs 8-Oxychlnohns untl dcs Chlnohns vcrghchcn Dlc spcktrophotomctrlach und such potcntlomctrlsch bentlrnmtcn Dlsqozlntlonskonetantcn dcs q-Oxyb-cnrth~nzols pctgcn, dnqs dlcscscrc clnc starker0 S$rlro untl achwz\chcro Bnsc 1st als das &Oxychlnolrn REFERENCES ' 1-1 ~RLENMRYI~RAND