Aggregation of Surfactants: Catalytic Reinforcement in Oxidation of Unsaturated E-Crotonaldehyde

In this work, the kinetics of the micellar catalyzed oxidation of the unsaturated aliphatic aldehyde, E-crotonaldehyde in aqueous medium under pseudo 1st-order reaction condition was spectrophotometrically investigated at 25 °C. In the spectrophotometric measurement, the rate of the reaction was recorded by the decreasing intensity of the metallic oxidant, hexavalent chromium [Cr(VI)], in acidic aliquots at 450 nm with varying concentration of surfactants and/or heteroaromatic promoters. Spectral evidences have been produced in favour of the mechanistic approach and the product formation.

Micellar and Transition Metal Ion Catalysed Oxidation of Pentanol in Aqueous Medium

Micelles and 4d- or 5d-transition metal ions have been proved to be effective catalysts for the oxidation of 1-pentanol by Ce(IV) in aqueous medium under pseudo 1st order reaction conditions at 258C. Although cationic micelles show a speed retarding effect, anionic SDS micelles accelerate the reaction rate. The Ir(III) and Ru(III) catalysed reactions show shorter half-lives at micromolar concentration. Active Ce(IV) species are also identified and an explanation of the different catalytic activities of metal ions and micelles is presented. The accumulation of the substrate in the Stern-layer of the SDS micelles is detected. The reaction product is confirmed by melting point analysis, a 2,4-DNP test, and by IR and NMR studies.

Synthesis of Alkylbenzene from Medium-Chain Olefins Catalyzed by an Acidic Ionic Liquid and the Surface Properties of Their Sulfonate

The Fischer-Tropsch synthesis can be used to achieve a high content of α-olefin (C5–C11) products using Fe-based catalysts. Herein, C6 and C8 α-olefins have been selected as examples for the alkylation of benzene catalyzed by using an acidic ionic liquid (Et3NHCl-AlCl3) to obtain a variety of intermediates used to prepare surfactants. A series of alkylbenzenes were synthesized by controlling the reaction conditions and their corresponding alkylbenzene sulfonates were successfully obtained by sulfonation and neutralization. It was found that the single chain alkylbenzene sulfonate derivatives did not display typical surfactant properties due to their short hydrophobic chain length. However, double chain alkylbenzene sulfonates exhibit excellent surfactant properties, and decrease the water surface tension compared to commercially available sodium dodecylbenzene sulfonates. A γ cmc (mN m−1) value of 32.70 was observed for sodium di-hexylbenzene sulfonates, 29.98 for sodium di-octylbenzene sulfonates, and 36.0 for sodium dodecylbenzene sulfonates. In addition, double chain alkylbenzene sulfonates show an improved emulsifying and wettability performance compared to sodium dodecylbenzene sulfonate. This demonstrates that the capability of alkylbenzene sulfonate to decrease the surface tension are closely related to the total carbon number of side chain-alkyl groups connected to the benzene ring.