Journal of Surfactants and Detergents

Luo, Xiao‐min; Ren, Long‐fang; Zhang, Xiao‐lei; Qiang, Tao‐tao

doi: 10.1007/s11743-008-1091-5pmid: N/A

A SO42−/ZrO2 super acid was prepared and the effect of different kinds of catalysts on the esterification reaction reviewed. The results showed that the SO42−/ZrO2 super acid had higher catalytic activity and reactive selectivity in the synthesis of oleic acid polyglycol ester. Under optimum conditions the product was a monoester and the rate of production was more than 90%. The reaction product was characterized.

Acosta, Edgar J.; Bhakta, Arti S.

doi: 10.1007/s11743-008-1092-4pmid: N/A

The HLD‐NAC model has been used as an “equation of state” to predict the properties of microemulsion (μE) systems formulated with either anionic or nonionic surfactants. The model uses the concept of the hydrophilic‐lipophilic difference (HLD) to calculate the chemical potential difference of transferring a surfactant from the oil to the aqueous phase; as a function of formulation variables such as type of surfactant, oil, temperature, electrolyte concentration. The value of HLD is used as a scaling parameter to calculate the net and average curvatures (NAC) of the surfactant at the water/oil interface. These curvatures determine the phase volumes, phase transitions, and solubilization capacity of μEs. In this work, the HLD‐NAC model is extended to nonideal surfactant mixtures of anionic and nonionic surfactants. The phase behavior of limonene μEs formulated with binary mixtures of sodium dihexyl sulfosuccinate with nonionic nonylphenol ethoxylates and alcohol ethoxylates was used to determine the deviations of the HLD from the ideal mixing behavior. The deviations were fitted using a 2‐parameters Margules equation. The results suggests that the deviations in anionic‐rich systems are due to the charge shielding effect of nonionic surfactants, and in nonionic‐rich systems, the deviations seem to be explained by the increase in hydration of the surfactant headgroups due to the presence of anionic surfactants. When these corrections were used to predict the curvature of dioctyl sulfosuccinate‐dodecyl pentaethylene glycol‐heptane μEs, the HLD‐NAC model corrected for the nonidealities reproduced not only the trends but also the actual range of values reported in the literature.

Bengoechea, C.; Cantarero, A. Samuel

doi: 10.1007/s11743-008-1100-8pmid: N/A

Linear alkylbenzene sulfonate (LAS) an ingredient of many household and industrial detergents can reach the environment after disposal of raw sewage. Its correct detection and quantification in different environmental samples is a critical issue for evaluating its environmental fate. This paper outlines a validation of an entire analytical procedure of LAS in environmental samples, including extraction, pre‐concentration and HPLC detection and quantification with fluorescence detection.

Li, Yi; Ye, Ru‐Qiang; Mu, Bo‐Zhong

doi: 10.1007/s11743-008-1094-2pmid: N/A

The properties of surfactin‐C16 aqueous solution in the presence of Na+ ions, produced by Bacillus subtilis, were studied by the fluorescence method. The critical micelle concentration (CMC) of surfactin‐C16 was measured as 24.7 μM in 0.05 M Tris buffer (pH 8.5–8.6). With an increase in Na+ concentration, the CMC value and micropolarity of surfactin‐C16 decreased while the microviscosity increased, which means that the addition of Na+ improves the surface activity and enhances the micellization of the surfactin‐C16 in solution. The preliminary aggregation number (N) was obtained by the steady‐state fluorescence method.

Khanmohammadi, Mohammadreza; Kojidi, Mohammadjavad Hosseinnia; Garmarudi, Amir Bagheri; Ashuri, Ahmad; Soleymani, Majid

doi: 10.1007/s11743-008-1101-7pmid: N/A

An analytical procedure was developed to monitor the batch reaction of coconut oil and diethanolamine which also would determine the cocodiethanolamide (CDEA) content of the final product. The method was based on attenuated total reflectance Fourier transform infrared spectrometry utilizing partial least squares regression. The calibration was modeled in the 1,781–1,714 and 1,658–1,639 cm−1 spectral regions for coconut oil and CDEA respectively. The models were then applied to predict the amidation process yield and to monitor the in situ kinetics of reactions between coconut oil and DEA. The root mean square error of prediction was 0.590 and 0.336 for coconut oil and CDEA respectively. The proposed method can also be successfully applied to the determination of purity in commercial grade CDEA samples and would give reliable results in comparison with the potentiometric titration reference method.

Obendorf, S. Kay; Liu, Haiqing; Tan, Kuitian; Leonard, Michael J.; Young, Timothy J.; Incorvia, Michael J.

doi: 10.1007/s11743-008-1103-5pmid: N/A

Surfactants enhance adsorption of an aroma chemical on cotton fiber. Strong hydrophobic and electrostatic interactions between surfactant and fiber substrate result in higher adsorption of surfactant/aroma chemical aggregates than for the aroma chemical alone, with higher adsorption for cationic systems than for anionic systems. Adsorption is attributed to solution physical entrapment, hydrophobic interaction, dispersion forces, and interaction with surfactant molecules adsorbed on fiber. Log P and water solubility are important factors in aroma chemical adsorption. Hydrophobicity increased selective partitioning of aroma chemicals on the fiber surface particularly in the presence of surfactants. Statistical analyses indicate some evidence of polar–polar interaction between aroma chemicals and cellulose. With no surfactant, more adsorption is often observed in systems with a higher concentration of NaCl. The screening effect of electrolytes increases with the electrolyte reducing the energy of the liquid–solid interface. Lower interfacial energy results in increased adsorption of an aroma chemical on the fiber surfaces. Electrolyte screening affects aroma chemical adsorption most for anionic surfactant systems. Increase in the concentration of the electrolyte increases the screening effect that reduces the repulsive forces between the anionic molecules and weakly electronegative cotton fiber surfaces. In a cationic system, the screening effect of the electrolyte reduces adsorption of aroma chemicals with increased electrolyte concentration, due to the screening‐reducing attraction between cationic surfactant molecules and the fiber surface. Chemical functionality shows a significant effect (alkanol ≥ ketone ≥ aldehyde > ester) on adsorption. Adsorption increased with increasing molecule ovality. Statistical analyses indicate that molecular shape within a chemical class of compounds influences adsorption of the aroma chemical.

Chantraine, Florence; Viana, Marylène; Pouget, Christelle; Brielles, Nelly; Mondain‐Monval, Olivier; Branlard, Paul; Rubinstenn, Gilles; Chulia, Dominique

doi: 10.1007/s11743-008-1090-6pmid: N/A

The aim of this study is to limit the hurdles generated by the presence of a surfactant, i.e., sodium dodecyl sulfate (SDS), in effervescent detergent tablets containing a chlorine provider. The results are highlighted by investigating the tablet's functional characteristics (mechanical strength, disintegration time). A second objective is to increase the surfactant content of the tablet in order to improve the cleaning properties of the detergent formula without retaining the previous drawbacks. For low tablet porosity, mechanical properties are damaged by the presence of 2% of SDS and while disintegration through an erosion mechanism is slowed down. Experimental evidence indicated that these phenomena are associated with the coexistence of SDS and sodium dichloroisocyanurate (DCCNa). Their separation by locating SDS in the tablet core was encouraging but had limited value due to the slow dissolution of the SDS core. The problem was solved when 2% SDS was concentrated on one face of the tablet; however, a higher concentration induced a delayed disintegration due to the progressive erosion of SDS, which behaved as a massive solid. The coating of the tablet with SDS was beneficial because the dissolution of the film delayed effervescence and consequently disintegration. Neither coating the SDS particles with cellulosic film nor including them in zeolite was an appropriate solution. On the other hand, segregating SDS and DCCNa by placing them in separate layers of the tablet produced very conclusive results when microcrystalline cellulose and an effervescent system were added to the SDS. Furthermore, this bilayer tablet allowed the SDS content to be increased while a satisfactory tensile strength and a low disintegration time were retained.

Fischer, Elmar; Fieber, Wolfgang; Navarro, Charles; Sommer, Horst; Benczédi, Daniel; Velazco, Maria Inés; Schönhoff, Monika

doi: 10.1007/s11743-008-1104-4pmid: N/A

The localization and dynamics of fragrance compounds in surfactant micelles are studied systematically in dependence on the hydrophobicity and chemical structure of the molecules. A broad range of fragrance molecules varying in octanol/water partition coefficients Pow is employed as probe molecules in an aqueous micellar solution, containing anionic and nonionic surfactants. Diffusion coefficients of surfactants and fragrances obtained by Pulsed Field Gradient (PFG)‐NMR yield the micelle/water distribution equilibrium. Three distinct regions along the log(Pow) axis are identified: hydrophilic fragrances (log(Pow) < 2) distribute almost equally between micellar and aqueous phases whereas hydrophobic fragrances (log(Pow) > 3.5) are fully solubilized in the micelles. A steep increase of the incorporated fraction occurs in the intermediate log(Pow) region. Here, distinct micelle swelling is found, while the incorporation of very hydrophobic fragrances does not lead to swelling. The chemical structure of the probe molecules, in addition to hydrophobicity, influences fragrance partitioning and micelle swelling. Structural criteria causing a decrease of the aggregate curvature (flattening) are identified. 2H‐NMR spin relaxation experiments of selectively deuterated fragrances are performed monitoring local mobility of fragrance and leading to conclusions about their incorporation into either micellar interface or micelle core. The tendencies of different fragrance molecules (i) to cause interfacial incorporation, (ii) to lead to a flattening of the micellar curvature and (iii) to incorporate into micelles are shown to be correlated.