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A novel series of surfactants was synthesized via direct interaction of the hydrogen-accepting benzyl monophenyl hydrazone and different hydrogen-donating sulfate, sulfonate, sulfosuccinate, or taurate species in their acid form. The double salt surfactants produced had a benzyl monophenyl hydrazonium (PH) moiety as the cation, and lauryl sulfate, dodecylbenzene sulfonate, dioctyl sulfosuccinate, N-cetyloxycarbonyl ethyltaurate (COCET), and N-stearyloxycarbonyl ethyltaurate as the anion. The structural elucidation of the synthesized compounds was carried out using different analytical tools such as elemental analyses, sharp melting points, and Fourier transform infrared and 1 H nuclear magnetic resonance spectroscopy. Surface properties of these synthesized hydrazonium derivatives, including surface tension and emulsion stability, were measured and correlated with their chemical structure. The corrosion inhibition efficiency of these hydrazonium derivatives at different concentrations (20, 40, 60, 80, and 100 ppm) was measured in brine containing 5% H 2 S as the corrosive medium. The inhibition efficiency results were discussed according to the inhibitor concentrations in the corrosive medium, chemical structures, surface properties, and hydrophile-lipophile balance of these inhibitors. The corrosion inhibition measurements of these compounds showed that PH-COCET exhibits good efficiency at all concentration ranges.Paper no. S1411 in JSD 8, 95-98 (January 2005).

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A weight loss technique was used to determine the corrosion inhibition efficiency of synthesized alkyl monoand dibenzoate triethanolammonium bromide derivatives (TEAMB, TEADB) in an acidic medium (2 N HCl) at different doses (50, 100, and 200 ppm). The results showed that monoderivatives had a higher corrosion inhibition efficiency than diderivatives. The results were correlated with several factors, including the alkyl chain length of the hydrophobic chains, interfacial tension (IT), critical micelle concentration (CMC), and adsorption free energy of these inhibitors. Increasing the geometric length of the alkyl chains in the synthesized inhibitors had an increasing effect on their corrosion inhibition efficiency, whereas decreasing the CMC and IT had an increasing effect on their tendency toward corrosion inhibition. The number of hydrophobic chains attached to the inhibitor molecules had a vital influence on their efficiency as corrosion inhibitors.Paper no. S1491 in JSD 8, 283-287 (July 2005).KEY WORDS: Adsorption free energy (∆G ads ), amphipathic structure, chemisorption bond, corrosion inhibition efficiency, critical micelle concentration (CMC), geometric length, geometric structure, interfacial tension (IT), physical adsorption, sweaty monolayers.Inhibitors are chemical substances added to a liquid to prevent corrosion or to control it at an acceptably low rate. They are used mainly in closed or circulating systems (1,2) and are selected for their effectiveness in protecting the specific metal or combination of metals in a given system. The corrosion of metals in aqueous solutions can be inhibited by a very wide range of substances (3-6) such as chloride, bromide, or iodide ions; carbon monoxide; and many organic compounds, particularly those containing elements of group V and VI such as nitrogen, phosphorus, oxygen, and sulfur. Organic compounds containing multiple bonds, especially triple bonds, are effective inhibitors. Organic compounds of high molecular weight (7), e.g., proteins and polysaccharides, also have inhibitive properties. This study is concerned with the evaluation of two synthesized cationic surfactants, i.e., alkyl mono-and dibenzoate triethanolammonium bromide (TEAMB and TEADB, respectively), as corrosion inhibitors for mild steel in an acidic medium (2 N HCl) at different doses. EXPERIMENTAL PROCEDURESSynthesis of alkyl mono-and dibenzoate triethanolammonium bromide derivatives. The synthesized inhibitors were described briefly in a previous study (8) as having the structures shown in Scheme 1. Corrosion inhibition measurement.A weight loss method was performed to measure the inhibition efficiency of the prepared alkyl mono-and dibenzoate triethanolammonium bromide derivatives for a mild steel specimen in a 2 N HCl solution. The composition of the mild steel specimen (wt%) was 0.2 C, 0.03 Si, 0.5 Mn, 0.8 P, and the remainder was Fe. The specimen was machined into a regular form electrode of 4 cm 2 cross-sectional area and 0.76 mm thickness. The specimen was sequentially abraded with di...

Five membered heterocyclic cationic 3-pyrazolium surfactants namely: 2-[2-(alkyloxy)-2-oxoethyl]-3-methyl-5-oxo-1-phenyl-4,5-dihydro-1H-3-pyrazolium bromide (decyl-; dodecyl-) and their copper and tin complexes were synthesized, their structures were confirmed using different spectroscopic tools. The IR spectra of the metal complexes showed that these compounds exhibit a tetrahedron structure with the transition metal ion (M 2? ) at the center and the cationic ligands arranged in the apexes, while the halide ions in the center. The synthesized compounds were evaluated as biocides against different types of bacteria and fungi. The biological activity data showed that the cationic surfactants exhibit moderate to high efficacy against the tested microorganisms (either bacteria or fungi). While, complexation of these cationic surfactants with Cu (II) and Sn (II) ions the antimicrobial activity was strongly increased. The surface activity of these compounds were discussed and correlated to their chemical structure and the type of substituents on the heterocyclic moiety. Meanwhile, the antimicrobial assay was correlated to the surface activities of the synthesized compounds.

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