Fatty Alcohol Ethoxylates Research Articles

Analysis of tensides in complex samples with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry

Multidimensional gas-chromatographical analysis of various tensides of natural or synthetic origin in cosmetic products is demonstrated. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry allows the qualitative and quantitative determination of alkyl polyglucosides (AG), fatty alcohol ethoxylates (FAEO), fatty alcohol sulfates (FAS), fatty alcohol ether sulfates (FAES) and cocamidopropyl betaines (CAPB) in shower gel and cleaning agents. The samples were aliquoted in two parts. The first part was silylated, diluted and analysed; then, in order to detect anionic tensides (FAES, FAS) too, the second aliquot was hydrolysed before being silylated for analysis. Because of their amphoteric character, the betaines can only be analysed by gas chromatography after thermal decomposition in the injector, which leads to the corresponding amidoamines among other products.

Modification of the activity of an alpha-amylase from Bacillus licheniformis by several surfactants

The influence of different commercial surfactants on the enzymatic activity of a commercial α-amylase from Bacillus licheniformis (Termamyl 300 L) has been studied. As non-ionic surfactants, alkyl polyglycosides (Glucopon® 215, Glucopon® 600 and Glucopon® 650) were studied, as were fatty alcohol ethoxylates (Findet 1214N/23 and Findet 10/15), and nonyl phenol ethoxylate (Findet 9Q/21.5NF). Also, an anionic surfactant, linear alkyl benzene sulfonate (LAS) was assayed. In general, none of the non-ionic surfactants studied, except Findet 10/15, vary substantially the enzymatic activity. Findet 10/15 has the strongest hydrophobic character and reduces the enzymatic activity more significantly the greater its concentration. Regarding LAS, this surfactant significantly depressed enzymatic activity, presumably due to the electrostatic interactions caused by its anionic character.

Association between a sodium salt of a linear dodecylbenzene sulphonate and a non-ionic fatty alcohol ethoxylate surfactant during film formation of styrene/butadiene latex

The influence of a linear anionic dodecylbenzene sulphonate (SDBS) and a non-ionic fatty alcohol ethoxylate (AE) surfactant on the compatibility and surface morphology of a medium carboxylated styrene/butadiene latex film was established. The latex films were prepared onto a mica substrate and annealed at 80 °C for 30 min. The AFM topography and phase contrast images enabled the localization of the surfactants on the latex films. The roughness parameters calculated for the captured images were utilized in order to identify the surface characteristics and changes caused by film ageing and addition of different surfactants. Both surfactants, but especially SDBS, increased the contrast between the latex particles. Addition of a blend of AE and SDBS surfactants to the latex emulsion resulted in the formation of hydrophobic nano-sized aggregates located at latex particle–particle boundaries in the films. The formation of the aggregates is ascribed to the association between the anionic and non-ionic surfactants. The segregated anionic surfactant was randomly distributed on-top of the latex films, whereas the surfactant blend showed a highly ordered, branched texture.

Nonionic surfactant-selective electrode and its application for determination in real solutions

A liquid membrane nonionic surfactant sensitive electrode has been prepared, based on a new barium pseudocationic complex of a highly ethoxylated fatty alcohol polyglycol ether and tetraphenylborate as sensing material. The complex has been incorporated into the plasticized PVC-membrane and used as sensing material. The electrode exhibited positive linear non-Nernstian response toward different nonionic surfactants and sub-Nernstian response toward tetraphenylborate with the lower detection limit of 3.3 × 10 −7 mol dm −3 in barium chloride solution. The interfering effect of some alkaline, alkaline earth, and heavy metal cations, has been demonstrated by displaying their calibration curves compared with that of Triton X-100. The electrode has been used as an end-point indicator for potentiometric titration of analytical and technical grade polyethoxylated nonionic surfactants, modelled detergent products, and commercial detergents.

On the determination of underivatised fatty alcohol ethoxylates by electrospray ionisation–mass spectrometry

The oligomers of fatty alcohol ethoxylates (FAEs) exhibit large sensitivity differences in mass spectrometry with electrospray ionisation (ESI–MS) and atmospheric pressure chemical ionization (APCI). Standards of the oligomers from m = 1 to 7 ethylene oxide units (EOs) and linear alkyl chains from n = 10 to 18 carbon atoms were infused to examine the relative sensitivities or response factors in several media. The response factors of the [M + H] + and [M + Na] + peaks in 9:1 acetonitrile/water and methanol/water media containing acid buffers increased following irregular patterns when n and m increased. In methanol/water the response factors depended on the parity of m, being larger than the average trend for the oligomers with an even value of m with respect to those having an odd value. This was attributed to the presence of an uncompensated C–O–C or C–O–H dipole in the former oligomers. The advantages of using ESI over APCI and of measuring the [M + H] + peaks in an acid methanol/water medium containing 0.1 M HCl are discussed. The advantages and limitations of using models of the response factors to evaluate oligomer concentrations with a reduced set of selected standards are examined. The determination of underivatised FAEs using acid media was made compatible with previous HPLC separation by implementing either a triconcentric nebulizer fed with an acid liquid sheath, or a capillary T-union inserted between the column outlet and the biconcentric nebulizer, and fed with an acid stream provided by a syringe pump.

Enzyme‐based detergent formulas for fatty soils and hard surfaces in a continuous‐flow device

AbstractThe present work analyzes the effect of incorporating a lipolytic enzyme (Lipolase® 100L) into detergent formulas for washing fatty soils on hard surfaces. The experimental device, which is called a “bath‐substrate‐flow” device, uses a continuous flow on a substrate (glass spheres) soiled with triolein. Washing tests were done using only the enzyme and changing both its concentration and the temperature of the process. The results showed that, in the presence of lipase, soil removal was achieved through three consecutive mechanisms: (i) fundamental devoval of the soil by the bath flow through the experimental device; (ii) emulsion of the soil in the washing medium; and (iii) enzymatic hydrolysis of the dispersed soil. Different commercial surfactants were used, and detergency was evaluated in the absence and presence of lipase. The use of surfactant formulas with the lipolytic enzyme showed a positive effect of the enzyme on the detergency values registered with the fatty alcohol ethoxylate surfactants Findet® 10/15 and Findet 1214N/23, and with the anionic surfactant linear alkylbenzene sulfonate. The commercial surfactants Glucopon® 600, Glucopon 650, Findet 10/18, and Findet Q/21.5NF alone each presented high detergency values for fatty soils, and the effect of the incorporation of the lipase was not significant.

Study by isothermal calorimetry and electrophoresis of the interaction between latices and cellulose derivatives

The influence of the latex surface chemistry on the association of latices with different cellulose derivatives has been investigated by means of isothermal calorimetry and electrophoresis. The chemistries of three grades of coating latices differed with regard to the type and amount of vinylic monomer and the level of carboxylation. In addition, a styrene/butadiene latex substantially free from surfactant was used to establish the influence of physically pre-adsorbed surfactants on the association with the cellulose derivatives sodium carboxymethylcellulose (NaCMC), hydroxyethylcellulose (HEC) and ethyl(hydroxyethyl)cellulose (EHEC). The results show that the latex chemistry, in terms of hydrophilic character originating from carboxylic acid groups, significantly affects the adsorption of the non-ionic HEC and EHEC. A higher degree of carboxylation or a more polar latex, such as vinyl acetate/acrylate, reduces the association with non-ionic cellulose derivatives. The addition of anionic sodium dodecylbenzene sulphonate or non-ionic fatty alcohol ethoxylate surfactants to the surfactant-free styrene/butadiene latex emulsion did not significantly change the association behaviour with EHEC, although it was evident that, for example, a sodium dodecyl sulphonate type of surfactant participated significantly in the adsorption process. Even if the surface polarity of the latex governs the association characteristics at the interface, the solubility properties of the cellulose derivatives must be considered, meaning that the hydrophobic character plays an important role in the associative interaction between the latex and cellulose derivatives in aqueous media.

Ozonation Impact on Degradation and Toxicity of Non-Ionic Surfactants

Aqueous solutions of five selected non-ionic surfactants: Triton (i-octylphenolethoxylates), Tergitol (2,6,8-trimethyl-4-nonanoloxethylates), Symperonic (n-nonylphenol-oxethylates) and Brij (fatty alcohol ethoxylates) were investigated in this study. Using the bioluminescent bacteria Vibrio fischeri the toxicity of the surfactants solutions were determined. An attempt was made to relate rather low biodegradability of nonionic surfactant solutions measured by the BOD5/COD ratio (ranging from 1 to 17%) to their toxicity. The ozonation process was carried out in a 1.5 dm3 stirred cell reactor equipped with two ozone detectors. The following parameters were analyzed: pH, COD, BOD5, DOC, TOC, polarography as well as UV spectrum. The positive effect of ozonation, represented by decay of UV absorption, was visible in almost complete destruction of the surfactants, with exception of Triton X-705 (only 65% degradation after absorption of 2000 mgO3/dm3). The most striking results were obtained in toxicity tests for ozonated solutions of the non-ionic surfactants – an increase of the bacterial growth inhibition (1.5 to 4 times increase in toxicity due to ozonation). The obtained results were discussed taking into account the literature and our own experimental data on mechanisms of ozonation and biodegradation of non-ionic surfactants of the Triton-type and similar chemical structures.

Rapeseed Methyl Ester Ethoxylates: A New Class of Surfactants of Environmental and Commercial Interest

Abstract The two last decades have been marked by an increasing environmental awareness. In relationship to detergents, renew-ability, biodegradability, and ecotoxicity have become important issues in the study, development and application of surfactants. In this respect, rapeseed methyl ester ethoxylates are an interesting new class of nonionic surfactants that gain more and more interest on the market. They are easily to formulate into attractive liquid detergents with high cleaning performance and show a more favorable ecotoxicological profile compared to fatty alcohol ethoxylates.

Determination of average molecular weight of commercial surfactants: Alkylpolyglucosides and fatty alcohol ethoxylates

AbstractA quick and simple method, based on elemental and moisture analyses, is proposed for estimating the mean molecular weight of alkylpolyglucosides and fatty alcohol ethoxylates, which are nonionic surfactants that are attracting growing interest for their ease of biodegradation. Analyses for the water content and the elemental composition were carried out for three alkylpolyglucosides (Henkel‐Cognis): Glucopon 215, Glucopon 600, and Glucopon 650, as well as for five fattyalcohol ethoxylates (Kao Corporation): FINDET 10/15, FINDET 10/18, FINDEt 1214N/16, FINDET 1214N/23, and FINDET 1618/A18. Application of the method requires knowing the mean number of carbons in the fatty acid chains of the surfactant. This number, in the case of the alkylpolyglucosides assayed here, has been determined experimentally by high‐performance liquid chromatography.

HPLC–NMR of fatty alcohol ethoxylates

The application of HPLC-NMR for the analysis of a mixture of fatty alcohol ethoxylates (FAEs) is described. The use of the new generation, cryogenically cooled probes is investigated in respect of the sensitivity advantage that they provide. The FAE mixture is separated using liquid chromatography at the critical point of adsorption. The ability of the method to differentiate between the different end groups and the degree of polymerization of the mixture constituents is investigated. Both on-flow and stop-flow HPLC-NMR techniques were used together with two-dimensional NMR spectroscopy. The results are compared with those obtained by using an evaporative light scattering detector for the HPLC.

Liquid chromatography of polyoxyethylenes under critical conditions: A thermodynamic study

Polyethylene glycols (PEG), fatty alcohol ethoxylates (FAE) and fatty acid polyglycol esters were analyzed by liquid chromatography under critical conditions (LCCC) on typical reversed phase columns in mobile phases consisting of methanol–water and acetone–water in the region of the critical adsorption point (CAP) for the oxyethylene unit. Critical conditions can be adjusted by varying the mobile phase composition or temperature. In methanol–water the temperature dependence is almost negligible, while it is much more pronounced in acetone–water. Critical conditions for the oxyethylene unit were realized on octadecyl phases in methanol–water containing 85.8 wt.% methanol and in acetone–water at 89.6 wt.% acetone. In the van’t Hoff plots the logarithm of the distribution coefficient was plotted versus the reciprocal temperature. In all plots straight lines were found, from slope and intercept of which the entropy and enthalpy changes were calculated. The relation of the thermodynamic parameters −Δ G/ RT, −Δ H/ RT, and Δ S/ R to the numbers of A and B chain units in block copolymers AB and BAB at the CAP for A is studied both theoretically and experimentally. Various approaches for obtaining the critical temperature are discussed.

Microemulsions with Palm Oil Derivatives Stabilized by a Nonionic Surfactant: Effects of Temperature and Cosurfactant

Microemulsions were prepared with palm oil derivatives as solvents at variable temperature. In addition, the effects of temperature and 1‐pentanol as cosurfactant on the microemulsion region were also studied. Results show that the solubility of palm‐based esters (POMEs) increased significantly in Imbentin coco 6.9EO, a commercial fatty alcohol ethoxylate, when the temperature was raised at 30°C to 40°C, 50°C, and 60°C. However, the solubility of palm kernel‐based medium chain triglycerides (PK‐MCT) did not increase much even though the temperature was raised to 60°C. This might be due to the fact that the cloud point for POMEs in Imbentin 6.9EO solution was below 60°C, but the cloud point for PK‐MCT in Imbentin coco 6.9EO solution was higher than 60°C. The formation of a large microemulsion region was observed at a 50:50 ratio of oil to water for POMEs in Imbentin coco 6.9EO system. The optimum concentration of cosurfactant and surfactant that formed microemulsions was 5% and 20% (w/w). However, the formation of a large microemulsion region was obtained at a 25:75 ratio of oil to water for PK‐MCT in Imbentin coco 6.9EO. The optimum concentration of cosurfactant and surfactant that produced microemulsions was 15% and 25% (w/w) respectively.

A nucleophilic substitution reaction in microemulsions based on either an alcohol ethoxylate or a sugar surfactant

A nucleophilic substitution reaction between 4- tert-butylbenzyl bromide and a series of iodide salts has been performed in oil-in-water microemulsions based on either a fatty alcohol ethoxylate or a sugar surfactant. The reaction kinetics was compared with the kinetics of the same reaction performed in a microhomogeneous reaction medium, d-MeOH. Previous results showing a particularly high reactivity in the microemulsion based on the fatty alcohol ethoxylate was confirmed. It was shown that in both microemulsions the reaction rate was almost independent of the choice of counterion to iodide. This indicates that complexation of the cation with the surfactant headgroup, which, in particular, could have taken place with surfactants containing oligooxyethylene chains (a “crown ether effect”), seems not to be of importance. 127I NMR studies, as well as quadrupole splitting experiments performed by 2H NMR, indicate that there is a certain accumulation of iodide at the oil–water interface of the microemulsions. It is difficult to draw any quantitative conclusions in this respect, however. The results obtained in this study, combined with results from previous investigations of the same reaction, indicate that the unexpectedly high reactivity obtained in the microemulsion based on a surfactant containing an oligooxyethylene headgroup is most probably due to the nucleophile being poorly solvated when present in the headgroup layer of such a microemulsion. Poorly solvated anions are known to be highly reactive nucleophiles.

Thermodynamic study of retention in liquid exclusion–adsorption chromatography

The retention behaviour of fatty alcohol ethoxylates and fatty acid methyl ester ethoxylates on various reversed-phase columns in acetone–water has been studied in the regime of liquid exclusion–adsorption chromatography at different temperatures. Straight lines were obtained in the van’t Hoff plots. The entropy and enthalpy changes were found to be negative (at least in the range of lower oligomers) and showed a dependence of the number of oxyethylene units. For higher oligomers, both entropy and enthalpy changes approach a constant value. This can be explained by the existence of a rather thick layer of organic solvent close to the surface of the stationary phase.

Matrix‐assisted laser desorption/ionization mass spectrometry of synthetic polymers. 7. analysis of fatty alcohol ethoxylates by coupled liquid chromatography at the critical point of adsorption and MALDI‐TOF mass spectrometry

AbstractFatty alcohol ethoxylates can be analyzed efficiently with respect to functionality and molar mass by coupled liquid chromatography and MALDI‐TOF mass spectrometry. Both techniques are coupled via a robotic interface, where the matrix is coaxially added to the eluate and spotted dropwise onto the MALDI target. It is shown that liquid chromatography at critical conditions of adsorption coupled to MALDI‐TOF yield useful structural information on oligomer masses and chemical composition. In particular, the analysis of technical fatty alcohol ethoxylates by LC‐CC/MALDI‐TOF reveals the presence of different functionality fractions in one sample. The oligomer distributions of all functionality fractions are determined.

Retention mechanism of fatty alcohol ethoxylates in reversed-phase liquid chromatography

Fatty alcohol ethoxylates (FAEs) are widely used nonionic surfactants that have distributions in both alkyl and poly(ethylene oxide) (PEO) chain length. Generally, two-dimensional liquid chromatography technique is required for the complete characterization of both distributions. By selecting a proper stationary and mobile phase condition, however, we can obtain fully resolved chromatograms of a FAE sample (Brij 30) with respect to both alkyl and PEO chain length by using a single reversed-phase C 18 column and aqueous acetonitrile mobile phase. FAEs show a peculiar reversed-phase liquid chromatography (RPLC) retention behavior with an aqueous–organic mobile phase, the retention mechanism of which has not been fully elucidated. For a fixed alkyl chain length, FAEs with higher-molecular-mass PEO block elutes first and the van’t Hoff plot of the retention factor shows a curvature. The unique retention behavior can be understood from the opposite thermodynamic characteristics associated with RPLC retention of PEO block and alkyl chain: the sorption process of PEO to the non-polar stationary phase shows Δ H o>0 and Δ S o>0 while the alkyl chain shows Δ H o<0 and Δ S o<0 in contrast. The relative magnitude of the two contributions can change the elution order of the FAE. Therefore the often found, inverted elution order of FAEs (the early elution of FAEs with longer PEO block) is due to the positive enthalpic interaction of PEO blocks, which is a characteristic of the hydrophobic interaction. And the curvature of the van’t Hoff plots was analyzed assuming the temperature dependent thermodynamic variables.

Primary oxidation products affect the quantification of formaldehyde in autoxidized fatty alcohol ethoxylates when using DNPH derivatization.

Non-ionic surfactants, e.g. fatty alcohol ethoxylates, are considered to cause less skin irritation than other types of surfactants. However, the autoxidation of alcohol ethoxylates generates products that are both skin irritating and sensitizing, such as formaldehyde. It has been suggested that formaldehyde be used as an indicator of the degree of autoxidation of fatty alcohol ethoxylates, and thus also as an indicator of the sensitizing capacity of the product. Attempts to analyse formaldehyde in autoxidized ethoxylates using 2,4-dinitrophenylhydrazine derivatization resulted in formation of the corresponding hydrazone not only from free formaldehyde but also from autoxidation products during the derivatization reaction. Consequently, this derivatizing agent is inappropriate for the determination of formaldehyde in autoxidized fatty alcohol ethoxylates. Focus on the content of primary oxidation products, i.e. hydroperoxides/peroxides, is suggested, particularly as they also are potent sensitizers.

Quantitative determination of non-ionic surfactants by high-performance liquid-chromatography-ion trap mass-spectrometry

This work presents a method for the qualitative and quantitative analysis of non-ionic surfactant of the fatty alcohol ethoxylate and nonylphenyl ethoxylate types in lanolin.

The Influence of Stabilizing Agents on the Interaction between Styrene/Butadiene Latex and Calcium Carbonate: A Calorimetric and a Dynamic Electrokinetic Study

The role of stabilizing agents in the interaction between styrene/butadiene latex and calcium carbonate particles has been studied using isothermal titration calorimetry (ITC) and an electrokinetic sonic amplitude (ESA) technique. It is demonstrated that the polyacrylate sodium salt (dispersing agent, referred to as NaPA) used as stabilizing agent for the calcium carbonate suspensions principally affects the interfacial properties of the calcite surface. An electrostatic barrier is created and this decreases the attractive interactions between the latex and the negatively charged mineral surface. The total enthalpy change observed when an emulsion of styrene/butadiene particles substantially free from surfactant was added to the dispersed calcium carbonate could be described via a relatively complex path. The process included (i) an exothermic response from the association of the latex particles (adsorption process) with the dispersed calcium carbonate surface and (ii) an endothermic bulk phase effect due to the adsorption on the latex particles of dissolved species originating from the calcium carbonate. Stabilization of the latex particles with sodium dodecyl benzene sulfonate (SDBS) or a non-ionic fatty alcohol ethoxylate surfactant did not significantly change the enthalpy of interaction. It was further demonstrated that SDBS had a very weak affinity for the dispersed calcium carbonate particles and that dissolution of species, such as calcium ions, from the calcium carbonate surface, allows further adsorption of SDBS onto the latex particles.