Na 2 SO 4 , pH=3). Dobijeni rezultati ukazuju na dobru inhibitorsku efikasnost ispitivanog derivata
UVODBakar i njegove legure spadaju u važan konstrukcioni materijal koji je često izložen kiseloj sredini prilikom prečišćavanja, pri otklanjanju korozionih proizvoda sa prenosnika toplote, elektrohemijskog glačanja, itd. Najčešće korišćena kiselina u ovim procesima je sumporna kiselina, u čijem prisustvu može doći do korozije bakra, pošto je formiranje pasivnog oksidnog sloja na površini metala onemogućeno [1]. Zaštita bakra u kiseloj sredini se najčešće vrši primenom korozionih inhibitora. Veliki broj molekula je do sada ispitivan kao potencijalni inhibitor korozije bakra. Na osnovu objavljenih rezultata uočljivo je da dobre inhibitorske osobine imaju organski molekuli koji u svojoj strukturi sadrže heteroatome azota, sumpora ili kiseonika [2][3][4][5][6][7][8]. Najveći broj njih ispoljava dobru inhibitorsku efikasnost u neutralnoj sredini, dok je broj jedinjenja sa dobrim zaštitinim osobinama u kiseloj sredini limitiran [9][10][11][12][13].Derivati tiazola spadaju u grupu jedinjenja koja se pokazala kao dobar inhibitor korozije bakra u kiselo-sulfatnoj sredini. Ovi organski molekuli svoje inhibitorsko dejstvo na koroziju pretežno ispoljavaju adsorpcijom na metalnu površinu usled čega se stepen korozije metala smanjuje [14][15].
5-(4-isopropylbenzylidene)-2,4-dioxotetrahydro-1,3-thiazole, (IPBDT) was tested as a potential copper corrosion inhibitor in 0.1 mol dm -3 Na 2 SO 4 solution at pH=3. Using dc polarization measurements and electrochemical impedance spectroscopy (EIS) the influence of the inhibitor concentration and temperature on the inhibitor efficiency was investigated. The obtained results suggested that IPBDT is a very good copper corrosion inhibitor in given condition, whose efficiency increases with the increase of the thiazole concentration as well as with the increase of temperature. EIS results showed that the inhibition effect of the thiazole manifests through an increase of the total resistance and a decrease of the double layer capacitance compared to the blank solution. The kinetic and thermodynamic parameters obtained by the polarization measurements, indicated that the copper corrosion in acidic sulfate solution occurs as an endothermic reaction and that the inhibitor molecules protect the copper during their chemisorption on the metal surface following the Langmuir's adsorption isotherm.
Barbituric acid derivatives have been pharmacologically significant compounds for decades. The central nervous system effects are conditioned by the presence of the pyrimidine-trione ring and the nature of the substituent in position 5. Lipophilicity as one of the key molecular descriptors of biological activity for selected barbituric acid derivatives was determined experimentally, using reversed-phase thin layer chromatography (RP TLC18 F254s), in two solvent systems. The influence of the substituent’s nature and the effects of applied organic modifiers on the chromatographic behavior of the tested derivatives were examined. For the studied derivatives the values of the partition coefficient (logP) as a standard measure of lipophilicity and effective concentration (EC50) as a measure of acute toxicity for different test organisms were calculated applying the appropriate software packages. Dependence between the chromatographic parameters as assumed measures of lipophilicity and the software-derived biological activity parameters of the studied barbituric acid derivatives were studied by linear regression analysis.
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