Corrosion Inhibition on Mild Steel by Phosphonium Salts in 1M HNO3 Aqueous Medium

The corrosion inhibition on mild steel by phosphonium salts in 1 M HNO3 medium has been investigated by weight loss and polarization techniques. The result revealed that these derivatives are excellent inhibitors. Potentiostatic polarization, impedance and electrochemical noise studies showed mixed type inhibitors. Ellipsometer, quantum chemical and FTIR results indicated Phosphonium bromide derivatives exhibit excellent corrosion protective thin layer performance

Scope of isoflavone synthesis using 2'-benzyloxychalkone epoxides

Boron trifluoride-etherate reacts with 2'-benzyloxychalkone epoxides to give mainly dihydroflavonols if ring B is unsubstituted, but isoflavones are formed by rearrangement if methoxy groups are present in positions 4 or 3 and 4. These factors limit the applicability of isoflavone synthesis using chalkone epoxides

Some reactions of substituted 2'- benzyloxychalkone epoxides

The behaviour of 2'-benzyloxychalkone epoxides towards acid reagents depends on the presence of substituents in the styryl part as well as on the reaction conditions. Ethereal hydrogen chloride under various conditions have been generally used but acetic acid alone or in conjunction with hydrobromic acid have also been used in a few cases. Simple 2'-benzyloxy-(I) and 2'-benzyloxy-4'-methoxy-(XIV) chalkone epoxides give only dihydroflavonols II and XV respectively; whereas 12'-benzyloxy-4-methoxy-(XIX) and 2',4'-dibenzyloxy-4-methoxy-(III) chalkone epoxides give various products depending on the conditions. From the latter epoxide (III), chlorohydrin (VI), glycol monoacetate (IX), 1,2-diketone (IV), and isoflavones (VII and VIII) have been isolated

SEM-EDS characterization of natural products on corrosion inhibition of Al-Mg-Si alloy

The corrosion resistance of aluminum and its alloys is the subject of tremendous technological importance due to their increased industrial applications. The corrosion protections and the mechanism of corrosion inhibitions of natural products for an Al-Mg-Si alloy in seawater were investigated at room temperature. The surface morphology was studied by means of macro scale electrochemical techniques and localized microscopic methods, i.e., Scanning electron microscope (SEM) with associated elemental analysis by energy dispersive spectrometer (EDS). SEM examinations provided morphological characterization of the surface of Al-Mg-Si alloy sample before and after immersion in seawater; meanwhile surface analytical techniques by the EDS allowed us to investigate detail the chemical composition of aluminum oxide layers. The experiments were performed with Al-Mg-Si alloy, immersed in a 5 L beaker containing seawater with and without the natural products for 60 days at room temperature. The SEM results indicate that the natural products (natural honey, vanillin, and tapioca starch) absolutely inhibited the corrosion products on the specimen surfaces. They also protected the passive film from dissolution in seawater. The EDS spectrums were determined that carbonaceous, carbonyl, methoxy and hydroxyl groups as functional groups of natural products in inhibition mechanism