- Preparation of benzalkonium salts differing in the length of a side alkyl Chain
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Benzalkonium salts are widely used as disinfectants, biocides and detergents, among a variety of other applications. The cationic surface-activity of these salts determines their potential to act as a biocide on both target and non-target organisms. In this study, a quick synthesis of a complete set of the benzalkonium salts differing in the length of an alkylating chain (from C2 to C20) is described. Moreover, their 1H-NMR, HPLC-MS, TLC and HPLC analysis were recorded.
- Kuca, Kamil,Marek, Jan,Stodulka, Petr,Musilek, Kamil,Hanusova, Petra,Hrabinova, Martina,Jun, Daniel
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p. 2341 - 2347
(2008/02/14)
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- Ternary Water in Oil Microemulsions Made of Cationic Surfactants, Water, and Aromatic Solvents. 1. Water Solubility Studies
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Two series of cationic surfactants have been synthesized and used to prepare water in oil microemulsions, with various aromatic solvents.The water solubility in these microemulsions and the phase behavior of the systems when the water content slightly exceeded the water solubility have been investigated as a fuction of surfactant chain length (variation of m), size of the sufactant head group (variation of n or p), nature of the counterion (substitution of Br(-) by Cl(-)), the molar volume, and the type of aromatic solvent.Mixtures of surfactant homologues have also been investigated: for instance, C16H33(C6H5)N(+)(CH3)2Cl(-) and C16H33(C6H5CH2CH2)N(+)(CH3)2Cl(-) or C16H33(C6H5CH2)N(+)(CH3)2Cl(-) and Br(-).The results concerning the effect of the surfactant chain length and the nature of the counterion and of the solvent have been interpreted in terms of the Hou and Shah model (Langmuir, 1987, 3, 1086) for the solubility of water in water in oil microemulsions.This model is based on the two main effects that determine the stability of these systems, namely, curvature of the surfactant film separating the oil and water and interactions between water droplets.The effect of the surfactant head-group size was found to be opposite to the prediction of this model.This is probably due to the fact that part of the head group of the synthesized surfactants passed from the water side to the oil side as its size was increased and, thus, acted as a cosurfactant.Our results become consistent with the Hou and Shah model if this cosurfactant effect of the head group is assumed to dominate the behavior of the systems.
- Jada, A.,Lang, J.,Zana, R.
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p. 381 - 387
(2007/10/02)
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- ETUDE DE LA CO-ADSORPTION DE TENSIOACTIFS SUR CHARBON ACTIF DANS L'EAU
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The purpose of this study is to examine the adsorption onto activated carbon of a cationic surfactant in micromolar quantity comparatively to anionic and nonionic surfactants formerly studied.The benzyldodecyldimethylammonium bromide : CH3(CH2)11(C6H5CH2)N(1+)(CH3)2Br(1-) (BBDDA) has been synthesized and puriied to compared also the adsorption properties of the benzyl group to the commercial hexadecyltrimethylammonium bromide.Mixed adsorption is studied with 2-naphthol and nonionic surfactants as co-adsorbats : nonyphenoxyheptaethoxyethanol (NP8) and dodecyletherpentoethoxyethanol (DE6).Langmuir or Freundlich isotherm equations were found to give a good representation of experimental data.The ultimate adsorption capacity (Γinfinite and equilibrium constants K were deduced : Γinfinite = 0.59 mmol/g and K = 5E-6 l/mol. Γinfinite is also estimated from kinetic curve and compared to Langmuir determination. the addition of NaCl and CaCl2 in the range 0-015M enhanced the adsorption capacity (by increasing K values) but Γinfinite was not significantly modified.However, the adsorption capacity for the cationic surfactant is quite reduced (K is diminished) in presence of 2-naphthol as co-adsorbat but Γinfinite has the some value.This shows the existence of specific adsorption sites for the two compounds.NP8 or DE6 diminished also the ultimate capacity adsorption of the BBDDA : Γinfinite + 0.38 for a mole fraction of 0.36 in NP8 and Γinfinite = 032mml/g for 0.47 in mole fraction of DE6; the carbon is saturated.The accurence of specific sites is infered using a model with an inhibition effect of the co-adsorbats.The "zero-potential" measurement on powered carbon suspension indicates that the initial negative value Γinfinite = -22 mV is incereased with NaCl or CaCl2 molarity, reaching -13 mV in 1E-2M NaCl and -9mV in 1 e-2M CaCl2.The cationic surfactant adsorption reduces also the zeta potential : its variation reaches 14 mV in 1E-4M CaCl2 or NaCl.Using the number of adsorbate molecules and Δξ we can estimate the thickness of the diffuse Debyae layer : 0.4 nm which indicates the proximity of the counter ions Br(1-) to ionic head group of cationic surfactant.
- Souabi, Salah,Dusart, Odile,Mazet, Michel
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p. 559 - 568
(2007/10/02)
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