Fatty Alcohol Ethoxylates Research Articles

The use of nonionic polymerizable surfactants in latexes and paints

In combination with anionic surfactants nonionic polymerizable surfactants lead to stable dispersions, which can be used as binders for paints. Generally the obtained results are worse than with a nonpolymerizable ethoxylated fatty alcohol. However the properties can be optimized through the right choice of the anionic surfactant. This further work is in progress.

Influence of interfacial properties of styrene/butadiene latex on the interaction with poly(vinyl alcohol) in aqueous media

The interfacial properties of styrene/butadiene latex were found to play a substantial role in its interaction with partially hydrolysed polyvinyl acetate (PVOH/Ac) in aqueous solutions. In particular, the level of carboxylation of the latex particles governs the adsorption process. A slightly hydrophobic PVOH/Ac is weakly adsorbed onto medium carboxylated latex at low equilibrium concentrations, whereas a multilayer adsorption occurs at high polymer concentrations, closely resembling the incipient phase separation already observed in the case of PVOH/Ac–polystyrene latex systems. The adsorption mechanism for the monolayer formation is suggested to be of entropic origin, driven by the hydrophobic interactions between the latex surface and especially the acetate groups of the PVOH/Ac chain. Increasing the hydrophilic character of the latex surface through pre-adsorbed sodium dodecylbenzene sulphonate or non-ionic fatty alcohol ethoxylate surfactants did not significantly affect the association behavior between PVOH/Ac and the latex surface. In addition to the importance of the interfacial properties of the latex particles, it has been shown that an increased degree of hydrolysis of the PVOH/Ac macromolecule also leads to an appreciable reduction in its affinity for the styrene/butadiene latex interface.

Biodegradation of oxo-alcohol ethoxylates in the continuous flow activated sludge simulation test

Biodegradation of two α-methyl branched oxo-alcohol ethoxylates (OAE) of different polydispersity: LIAL 125/14 BRD (LIALB) (broad M.W. distribution) and LIAL 125/14 NRD (LIALN) (narrow M.W. distribution), both having an average of 14 oxyethylene subunits (EO) and a C 12–15 alkyl moiety were tested under the continuous flow activated sludge conditions of the classical Husmann plant. Primary biodegradation and concentration of metabolites: free oxo-alcohol fraction (FOA) and poly(ethylene glycols) (PEG), were measured. PEG were divided into two fractions: short-chained PEG (PEGshch) (1–4 EO) and long-chained PEG (PEGlch)(>4 EO). The indirect tensammetric technique combined with an adequate separation was used for analysis. Central fission was found to be a highly dominating pathway, as is the case with fatty alcohol ethoxylates. OAE are highly primarily biodegraded (above 95%). High concentrations of FOA and PEG are formed. Once formed the PEGlch are further fragmented into the PEGshch. Free alcohol fraction compounds are biodegraded sooner when alkyl moiety is shorter. OAE polydispersity has an influence on the kinetics of biodegradation; PEG formed from LIALN are biodegraded slower and to a lower degree than those from LIALB.

Liquid exclusion–adsorption chromatography, a new technique for isocratic separation of nonionic surfactants: IV. Two-dimensional separation of fatty alcohol ethoxylates with focusing of fractions

Fatty alcohol ethoxylates can be analyzed using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. Transfer of fractions from the first to the second dimension is achieved using the full adsorption–desorption (FAD) technique. The peaks of interest in the first dimension are trapped on a short precolumn before injecting them into the second dimension. Full adsorption is achieved by increasing the water content in the mobile phase before the FAD column. When the fractions are desorbed by switching to the mobile phase of the second dimension, they are focused and reconcentrated. In this way, a full resolution of oligomers is achieved. As both dimensions are run in isocratic mode, density and refractive index detection can be applied, which allows an accurate quantitation.

Determination of short-chained poly(ethylene glycols) and ethylene glycol in environmental samples

A method for the determination of ethylene glycol (EG), di(ethylene glycol) (E2) and tri(ethylene glycol) (E3) in environmental samples (raw and treated sewage, river water) has been developed. These substances are important by-products in the biotransformation of non-ionic surfactants (NS). The method is based on sequential liquid–liquid extraction with ethyl acetate and chloroform (resulting in the separation of poly(ethylene glycols) (PEG) and EG from the water matrix), precipitation of long-chained PEG (PEGlch) with Dragendorff reagent, extraction of short-chained PEG (PEGsh) (EG, E2 and E3) from a filtrate with chloroform and the final determination using alternating current voltammetry. The precision of the method is 7.3%, the recovery 95% and a detection limit of 1.5 μg in the sample, i.e. 10 μg l −1 was achieved. As evidenced by F and t tests, the developed method is equivalent to the indirect PEGsh determination by the difference approach where concentration of PEGsh is determined by the difference of the total PEG and PEGlch. The PEGsh fraction was found to be present in considerable concentrations in raw and treated sewage, river water, as well as being a major biotransformation by-product in the continuous flow activated sludge testing of fatty alcohol ethoxylates.

Aggregation Behavior of Nonionic Surfactants Synperonic A7 and A50 in Aqueous Solution

The aggregation behavior of Synperonic A7 and A50, fatty alcohol ethoxylate nonionic surfactants (CmEn) with mean polyoxyethylene chain lengths of 7 and 50, respectively, was investigated in aqueous solution by means of surface tension, laser light scattering, steady-state fluorescence, and fluorescence quenching experiments. Surface tension measurements at room temperature indicate that the critical micelle concentration of A7 is 0.1 g/L (0.22 mM) and that of A50 is 0.17 g/L (0.07 mM). Static light scattering measurements reveal that the averaged aggregation number of A7 in water is 417 and that of A50 is 23. When solutions of A7 were allowed to age over a period of months at room temperature, the micelle Mw and hydrodynamic radius increased. The aggregation numbers found from fluorescence quenching measurements, using excimer formation from 1-ethylpyrene as a probe, were about 300 for freshly prepared solutions of A7 and about 40 for A50. We also found that the presence of air has a strong effect on the data obtained from the fluorescence quenching measurements.

Liquid exclusion adsorption chromatography, a new technique for isocratic separation of nonionic surfactants: III. Two-dimensional separation of fatty alcohol ethoxylates

A quantitatively accurate mapping of lower fatty alcohol ethoxylates can be achieved using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion–adsorption chromatography as the second dimension. With coupled density and refractive index detection in both dimensions, the contribution of preferential solvation can also be estimated. In most cases, however, the use of refractive index detection alone also yields satisfactory results.

Liquid exclusion–adsorption chromatography, a new technique for isocratic separation of nonionic surfactants: II. Quantitation in the analysis of fatty alcohol ethoxylates

A new technique of liquid chromatography, which allows baseline separation of fatty alcohol ethoxylates with up to 15–20 ethylene oxide units under isocratic conditions allows an accurate quantitative analysis of single hydrophobic chain surfactants. Using density and refractive index detection, the accurate weight fractions of the individual oligomers are obtained. Moreover, the contribution of preferential solvation can be determined. With refractive index detection alone, good accuracy can also be achieved.

Derivatization LC/MS for the simultaneous determination of fatty alcohol and alcohol ethoxylate surfactants in water and wastewater samples.

A new LC/MS method has been developed for the simultaneous measurement, in water and wastewater samples, of all species contained in commercial samples of linear type of alcohol ethoxylate (AE) surfactants including fatty alcohols. The method requires derivatization of the terminal hydroxyl of each surfactant species with 2-fluoro-N-methylpyridinium p-toluenesulfonate, which imparts a permanent cationic charge, allowing all species including the fatty alcohols and those with only one ethoxylate to be effectively detected by electrospray MS. Detection limits of typically <10 ppt for each individual species were attained in treated wastewater, in which total AE concentrations (combination of up to 114 individual species) are not expected to exceed 10 ppb. The method was validated for clean water as well as sewage influent and effluent samples.

Liquid exclusion–adsorption chromatography: new technique for isocratic separation of nonionic surfactants: I. Retention behaviour of fatty alcohol ethoxylates

A new technique of liquid chromatography is described, which allows a baseline separation of fatty alcohol ethoxylates with 15–20 ethylene oxide units under isocratic conditions. The new method is based on a combination of two different chromatographic modes for the individual structural units: size exclusion for the poly(oxyethylene) chain and adsorption interaction for the hydrophobic end fragments. A theory is provided for this mixed exclusion–adsorption mode of liquid chromatography. Chromatographic data are found to be in a good agreement with this theory.

Biodegradation of fatty alcohol ethoxylates in the continuous flow activated sludge test

Biodegradation of two fatty alcohol ethoxylates: surfactant C12E10 (C 12 with an average 10 oxyethylene subunits (EO)) and Marlipal 1618/25 (C 16–18 with an average 25 EO) were tested under the continuous flow activated sludge conditions of the classical Husmann plant and a plant having a denitrifying chamber. Primary biodegradation and concentration of metabolites: free fatty alcohol (FFA) and poly(ethylene glycols) (PEG) were measured. PEG were divided into two fractions: short-chained (1–3 EO) and long-chained PEG (>3 EO). Tensammetric methods were used for analysis. High primary biodegradation was found (96.8±0.5% for surfactant C12E10 (C12E10) and 99.6±0.1% for Marlipal 1618/25 (Marlipal)), though with a high concentration of metabolites: FFA and PEG. FFA concentration corresponded to 30–100% of theoretically predicted concentration (presuming central fission) and dependent on the chemical structure of surfactant and type of plant used for testing. Total PEG concentration was about 20% of that predicted on the basis of central fission, while the ratio of short-chained PEG in the total PEG varied from 20 to 70% and depended on the chemical structure of surfactant and type of plant used for testing.

Phase behavior and detergency study of lauryl alcohol ethoxylates with high ethylene oxide content

AbstractNonionic surfactants such as fatty alcohol ethoxylates have been extensively used in many detergent applications, because of their high calcium ion tolerance, low critical micelle concentrations, and mildness. Although ethoxylates containing high ethylene oxide (EO) content (EO&gt;10 moles) score higher than their low‐FO counterparts on many of these desired properties, they have not been studied adequately in the context of detergency, primarily because their cloud points (CP) are higher than normal wash temperatures, typically &gt;100°C, and thus cannot be measured. However, once the CP are manipulated appropriately using salting‐out electrolytes, these surfactants can offer certain distinct advantages in terms of their molecular and phase structure. We have studied the phase structure and clouding behavior of tetradecyl ethylene‐oxide mono dodecyl alcohol (C12EO14), a broad‐range ethoxylate, as a function of the concentrations of various electrolytes. We found that, beyond a certain critical concentration, the CP decreases monotonically with increasing salt concentration. For sodium salts of various anions, the CP depression is inversely proportional to the lyotropic number of the anion. Similarly, for chloride salts of various cations, CP depression is inversely proporitional to the lyotropic number of the cation However, the effect of changing anion is stronger than that of changing cation. A micrograph of a water penetration scan at room temperature indicates the presence of isotropic L1; hexagonal, isotropic L2; and solid phases with increasing surfactant concentration. As is the case with low‐FO nonionics, a maximum in detergency of model oily soils was found to correlate well with the minimum in oil/water interfacial tension when plotted vs. temperature. Ross Miles foam height increases with increasing concentration of salt.

Polydisperse ethoxylated fatty alcohol surfactants as accelerators of cuticular penetration. 2: Separation of effects on driving force and mobility and reversibility of surfactant action

Polydisperse ethoxylated fatty alcohol (EFA) surfactants can improve the performance of crop protection agents. At the cuticular level they act as accelerators of penetration by increasing the mobility of active ingredients in the cuticle, the barrier properties of which are mainly caused by cuticular waxes. Polydisperse Genapol C-050 (GP C-050, average formula C12.5E5.8) was also found to increase mobility in wax-extracted polymer matrix membranes (MX) of bitter orange and pear, indicating that sorption of surfactants increased segmental mobility of polymethylene chains in cutin and wax. Sorption into MX of the active fraction of GP C-050 from 5g litre−1 micellar solutions was in equilibrium in less than 1 h after establishing contact. This is almost 100-fold faster than with cuticular membranes (CM). Temperature dependence of solute mobilities in CM was studied in order to measure activation energies (ED) of diffusion in the presence and absence of aqueous surfactant solutions. Monodisperse fatty alcohol ethoxylates C8E3, C8E4 and C12E6, and (non-surface-active) tributylphosphate decreased ED of the model compounds WL 110547 and bifenox in Citrus, Pyrus and Stephanotis CM by more than 100 kJ mol−1. This corresponds to 50 to 275-fold increases of mobilities at 15 °C. Our data suggest that the decrease in activation energies with the concomitant accelerating effect on mobility contributes considerably to the effects of so-called activator surfactants. High temperature and accelerators act similarly on barrier properties of CM. It is shown that effects of both monodisperse and polydisperse EFA surfactants on solute mobility are reversible and that radiolabelled C12E8 penetrated pear CM rapidly. However, rates of penetration were lowered by excess amounts of WL 110547 and especially phenylurea. Partition coefficients of seven organic solutes between Capsicum fruit cuticles and GP C-050 were very low and, with the exception of methylglucose, smaller than 1. They decreased with lipophilicity and differed about 100-fold. Especially for the lipophilic compounds they were orders of magnitude lower than octanol/water or cuticle/water partition coefficients, which indicates the limited usefulness of these values for an understanding of penetration of active ingredients from formulation residues. © 1999 Society of Chemical Industry

Surfactant effects on cuticular penetration of neutral polar compounds: dependence on humidity and temperature.

Effects of poly(ethylene glycol) (PEG 400) and polydisperse fatty alcohol ethoxylates ("Genapols") on methylglucose penetration across cuticles of Pyrus communis were studied under different humidities and temperatures. All surfactants increased methylglucose penetration better than PEG 400. The efficacy was proportional to their own penetration. Genapol C-100 (C12.5E8.4; C, average number of carbon atoms in the alkyl chain; E, average number of ethoxy groups) effects were strongly concentration dependent (0.2-5 g/L). At 2 g/L distinct differences between surfactants were observed. Effects of Genapol C-050 (C12.5E5.8) did not depend on humidity (11-93% RH) and temperature (15-35 degrees C). They were maximal after application but decreased rapidly due to surfactant penetration. Genapol C-200 (C12.5E17) effects increased strongly with humidity and temperature both of which prevented its solidification. Genapol C-100 was superior under most conditions and never failed to increase penetration. There was no simple relationship between ethylene oxide content and surfactant effect.

Trace analysis of surfactants derived from fatty alcohols I. Optimization of derivatization reaction

Pre-column derivatization of the primary hydroxyl group in fatty alcohols and fatty alcohol ethoxylates using carbazole-9-carbonyl chloride (CC−Cl) and FMOC-Cl is described and compared with derivatization with 1-naphthoyl chloride (N−Cl). As the excess of derivatization reagent leads to a broad and strongly tailing reagent peak, it hinders trace determination of fatty alcohols and fatty alcohol ethoxylates. Therefore, an off-line as well as an on-line solid-phase extraction (SPE) method for removal of excess reagent are described. The on-line method which is based on column switching, shows better reproducibility higher pre-concentration, lower risk of contamination and can be easily automated, while the off-line method is better suited for the analysis of derivatized, fatty alcohol ethoxylates. An example of the trace analysis of fatty alcohols with a concentration of 2 ppb is given.

Aluminium alkoxide sulphate catalyst: a computational study

Aluminium alkoxide sulphate catalysts have been used to promote ethoxylation of fatty alcohols with a narrow distribution of the molecular weights. Based on experimental observations, a reaction mechanism and a related kinetic model able to simulate all the performed kinetic runs have been proposed in a previous work by M. Di Serio et al. [M. Di Serio, P. Iengo, R. Gobetto, S. Bruni, E. Santacesaria, J. Mol. Catal. A: Chem. 112 (1996) 235]. In the present work the plausibility of the mechanism suggested and the role played by the sulphate groups in the reaction have been evaluate by a computational study. The promoting effect on the reaction rate of sulphate groups is similar to that observed in the heterogeneous catalysis for different oxides treated with sulphuric acid, so the results obtained in this work will also be applied to explain the catalytic behaviour of sulphated alumina.

Separation of Nonionic Surfactants by Capillary Electrophoresis and High-Performance Liquid Chromatography

Fatty alcohol ethoxylates (FAEs) are applied in commercial formulations (laundry detergents) as complex mixtures of alkyl and ethoxylate homologues. Therefore, efficient analytical methods are required for product control. Capillary electrophoresis, a modern analytical separation technique, was used to separate FAEs in technical products and household formulations after derivatization with phthalic anhydride. The well-established high-performance liquid chromatography was used as reference and supplementary method. UV detection after derivatization with phenyl isocyanate or light scattering detection has been carried out. Sample components have been identified by standard addition or by comparison to known products. The peak pattern can be considered as a "fingerprint" of the product and is characteristic for a defined composition.

Narrow‐range ethoxylation of fatty alcohols promoted by a zirconium alkoxide sulfate catalyst

AbstractZirconium dodecanoxide sulfate is a very active catalyst in promoting fatty alcohol narrow‐range ethoxylation. The catalytic activity is initially very high but rapidly decreases after the addition of one mole of ethylene oxide per mole of substrate. This peculiar behavior makes it possible to obtain narrow‐range ethoxylated products containing not more than two or three ethylene oxide units. Because the catalyst shows a very feeble Brönsted acidity, it must be concluded that its activity originates from the Lewis acidity. This acidity is strongly enhanced from the introduction of the sulfate group in the catalyst molecule, because of the strong electron‐withdrawing effect of this group. A kinetic model was developed for explaining experimental results.

Theory of liquid adsorption chromatography of macromolecules applied to polyethylene glycol and fatty alcohol ethoxylates

Liquid adsorption chromatography retention modes of poly(ethylene glycol) (PEG), its mono- and dimethyl ethers (MMEs and DMEs) and also of fatty alcohol ethoxylates (FAEs) are studied both experimentally and theoretically. The experimental system under investigation was a Spherisorb S5W 80 Å column and isopropanol–water as the mobile phase. At various compositions of the mobile phase (in the range of 75 to 87% of isopropanol) chromatograms exhibiting good peak resolution were obtained and the dependencies of the elution volume on the number of repeating EO units for both PEG and FAE samples evaluated on the basis of a closer inspection of the chromatographic data. The experiments did not reveal any differences between the chromatographic behavior of PEGs, MMEs and DMEs, while the FAEs gave substantially smaller values of elution volume at all mobile phase compositions. These data were interpreted by using a molecular-statistic theory of homopolymers (to describe both PEG, MME and DME) and two-block copolymers (for FAEs) based on a continuum Gaussian chain model of macromolecules and a slit-like model of pores of stationary phase, wide pore approximation and the adsorption chromatography mode for PEG molecules were assumed in the development of this theory. This theory described very well the experimental data obtained, and two thermodynamic parameters characterizing interactions of EO units of PEG and both EO and (CH 2) n chains of FAE molecules with the adsorbent pore walls have been determined from the comparison of the theory and the experiments. Although the mean thickness of adsorbed oxyethylene chain, H, was estimated as being equal to about 3.5–4.5 Å, H proved to be slightly decreasing with increasing isopropanol content in mobile phase. Chromatograms visualizing the adsorption of PEG and FAE molecules are presented, and the correspondence between the theoretical approach and the experimental situation under investigation is discussed.

Polydisperse ethoxylated fatty alcohol surfactants as accelerators of cuticular penetration. 1. Effects of ethoxy chain length and the size of the penetrants

The effects of polydisperse ethoxylated fatty alcohol (EFA) surfactants on the penetration of six organic compounds varying in size (molar volumes, 107–282 cm3 mol-1) and lipophilicity (log Kow 0·8–6·5) were investigated using astomatous isolated cuticular membranes (CM) of Citrus and pear leaves. Mobilities of model compounds in CM were measured by unilateral desorption from the outer surface (UDOS). Rate constants (k*) obtained in these experiments are directly proportional to diffusion coefficients and, in the absence of EFA, k* values decreased by a factor of 52 when molar volumes increased only 2·64-fold. Under UDOS conditions using micellar surfactant solutions as desorption media, surfactants are sorbed in the CM and the volume fractions sorbed were found to decrease from approximately 0·062 to 0·018 when the average number of ethoxy groups (nE) increased from 5 to 17. In the presence of the EFA surfactants in the CM, solute mobilities increased markedly though this effect diminished with increasing nE. Surfactants with nE=17 affected solute mobilities only marginally. Surfactant effects on solute mobility increased with the size of the solutes leading to almost identical mobilities of the model compounds. With the current range of our model compounds, lipophilicity increased with increasing molar volumes, though evidence is presented showing that the mobilities of solutes depend on their molar volumes while lipophilicity has no effect. Effects of micellar aqueous solutions of polydisperse surfactants on solute mobilities followed the pattern observed with monodisperse ones. © 1997 SCI