No abstract

The modified organic wastes of the caprolactam are investigated by potentiodynamic and impedance technique as corrosion inhibitor of carbon steel in 20 mass % hydrochloric acid solutions. It is shown that the investigated inhibitor retards mainly anodic reaction. The corrosion process is simulated by a parallel circuit of constant phase element and the corrosion resistance connected in series with the solution resistance. The inhibition efficiency reaches 92 … 93 % at 1 mass % concentration of inhibitor.

Waste of the caprolactam production that is the POD-oil (Product of Oxidizing and Dehydrogenation) is investigated by gravimetric, potentiodynamic and impedance spectroscopy techniques. It is shown that dimer of hexanon (dianone) is the basic inhibiting component of the POD-oil. It is demonstrated that the POD-oil retards mainly the anodic reaction. The corrosion process is simulated by a parallel connection of the corrosion resistance and the element with constant phase at value of the exponential factor n = 0.71 -0.86. The efficiency of the investigated inhibitor reaches 85 -88% at 1 mass % concentration of the inhibitor.

A modified organic waste of the caprolactam production is investigated by electrochemical impedance spectroscopy technique as a corrosion inhibitor of carbon steel in 20% hydrochloric solution. It is shown that cyclohexylidenecyclohexanon is a basic inhibiting component in such inhibitor. The inhibitor is investigated also as surfactant at the solution – air interface by means of the maximum bubble pressure technique. It is shown that the Langmuir adsorption of inhibitor takes place at solution – air and solution – steel interfaces. Equilibrium adsorption constant values make (1.7±0.4)×103 M-1 and (4.0±0.8)×103 M-1 respectively. Free adsorption energy was estimated as (–28±0.5) kJ mol-1 and (–30±0.6) kJ mol-1 respectively. The closeness of the adsorption constant and the free adsorption energy values suggest that the inhibitor adsorption on steel is caused basically by the hydrophobic interaction of inhibitor molecules with the solution molecules and less depends on the interaction with steel.

Recrystallization of (E)-5-phenyl-1-(pyridin-2-yl)pent-2-en-4-yn-1-one at room temperature from ethylene glycol in daylight afforded [3,4-bis(phenylethynyl)cyclobutane-1,2-diyl)bis(pyridin-2-ylmethanone], C32H22N2O2 (3), while (E)-5-(4-methylphenyl)-1-(pyridin-2-yl)pent-2-en-4-yn-1-one, C17H13NO (2), remained photoinert. This is the first experimental evidence that pentenynones can be photoreactive when fixed in nearly coplanar parallel positions. During the photoreaction, the bond lengths and angles along the pentenyne chain changed significantly, while the disposition of the pyridyl ring towards the keto group was almost unchanged. The cyclobutane ring adopts an rctt conformation.