Alkyl Ethoxy Sulfate Research Articles

Phase Behavior and Rheological Properties of AES/CAPB/H2O Ternary System

Cleaning products are often formulated as mixtures of surfactants because the properties of surfactant mixtures are easier to adjust than those of a single surfactant. Therefore, it is of great significance to study the phase diagram of surfactant mixtures. In this paper, the phase behavior of the alkyl ethoxysulfate (AES)/cocamidopropyl betaine (CAPB)/H2O ternary system was investigated at room temperature using polarizing optical microscopy (POM) and small angle X-ray scattering (SAXS), and the identified phases of the samples with various compositions were used to construct the ternary phase diagram of the AES/CAPB/H2O system which contains normal micellar phase (L1), normal hexagonal phase (H1), lamella phase (Lα), and one transition region (L1 → H1). The viscosity distribution of the AES/CAPB/H2O system was determined by a Brookfield DV2T touch screen viscometer. In addition, the effects of the weight percentage of CAPB and salts on the viscosity and rheological properties of the AES/CAPB/H2O system were also investigated. This work not only enriches the phase diagram of surfactant systems, but also has important guiding significance for the design and development of cleaning products.

Using Raman Spectroscopy and Molecular Dynamics to Study Conformation Changes of Sodium Lauryl Ether Sulfate Molecules.

A study using both Raman spectroscopy and molecular dynamics (MD) simulations was carried out for alkyl ethoxysulfate (AES) surfactants at various concentrations in solution. Direct comparison between experiment and simulation shows that the conformational changes observed in MD are in good agreement with those obtained via Raman spectroscopy. We show that there is an increase in the relative number of trans conformations with increasing concentration and illustrate the relationship between phase structure and molecular conformation, which is often speculated but difficult to confirm. Our results open up the possibility of applying MD to other surfactants, with the aim of analyzing conformational behavior, which can typically be difficult to study experimentally using spectroscopy methods, due to large numbers of vibrational modes present in large complex molecules.

Formulation for chemical EOR: Development and evaluation of an ASP formulation In customer field conditions

AbstractAlkali surfactant polymer (ASP) flooding is an enhanced oil recovery (EOR) technology with an impressive potential for increasing incremental oil production from conventional hydrocarbon bearing reservoirs. A challenge to ASP application is the complexity of determining an effective formulation, typically requiring extensive laboratory screening of nearly countless combinations of surfactants and cosolvents. This paper focuses on demonstrating the utility of the hydrophilic–lipophilic deviation (HLD) concept for EOR application to simplify surfactant formulation workstreams seeking an economically viable ASP formulation for field application. In describing work performed for EOR application of ASP under customer conditions using crude oil, the discussion covers the initial evaluation of the promising surfactant formulation (interfacial tension and solubility), the improvement upon the formulation via HLD principles, and the evaluation of the improved surfactant formulation (coreflood studies). The final ASP formulation identified consisted of a 9 to 1 mixture of alkyl propoxy sulfate sodium salt (APS) to alkyl ethoxy sulfate sodium salt (AES) totaling 2000 ppm active surfactant content, 2.0 wt% Na2CO3, and 3000 ppm polyacrylamide polymer (all commercially available products). This formulation had ultra‐low interfacial tension and favorable mixing behavior under reservoir conditions. In coreflood studies, the final formulation reproducibly achieved cumulative oil recovery of 96.4%–98.5% of original oil in place with only 0.3 PV of ASP injection with a chase alkali polymer injection.

Phase Behavior and Rheological Properties of Poly(vinyl alcohol)/AES/Water System.

In this work, the phase behavior of the poly(vinyl alcohol) (PVA)/alkyl ethoxysulfate (AES)/water ternary system is investigated at 25 °C. The PVA/AES/water ternary phase diagram is conducted which shows that there are two main phases corresponding to the solid phase and the hexagonal liquid crystalline phase (H) in the ternary system. Besides these two phases, a high-viscosity liquid phase (L2) and a micellar phase (L1) can also be found in the phase diagram, although they just occupy small areas. Polarizing optical microscopy and small-angle X-ray scattering are used to characterize the different lyotropic liquid crystal types. Moreover, the viscosity distribution and oscillation tests are also performed by means of the rheometer. High elastic modulus (G') and viscous modulus (G″) can be found in the H and the L2 phase, whereas both moduli are low in the L1 region. The PVA/AES/water ternary phase diagram provides a good guide for accelerating the selection of the detergent formula, whereas the rheological tests provide an application guidance for industrial operations. Beyond tis, the L1 region is considered to be a reasonable range for slurry making because of its good fluidity and low viscoelasticity. This research enriches the content of polymer-surfactant aggregates and promotes the development of solid detergent manufacturing industry.

Effect of tail branching on the phase behavior and the rheological properties of amine oxide/ethoxysulfate surfactant mixtures

The formulation of highly concentrated products with low viscosity is a key issue of the surfactants industry, for both economic and ecological reasons. The rational design of surfactant tails bearing a limited number of short side chains has been proposed as a suitable strategy to meet this demand, with negligible effects on biodegradability.In this work, we investigate a mixed surfactant system, in which the branched surfactant N,N-dimethyl-2-propylheptan-1-amine oxide (C10DAO-branched) is combined with a linear alkyl ethoxysulfate one (AES). For comparison, we also study the mixtures in which the branched amine oxide is replaced by its linear isomer (C10DAO-linear).The phase behavior of this surfactant mixture in water is investigated across the entire composition range by polarized optical microscopy and small angle X-ray scattering. Moreover, the shear viscosities and viscoelastic moduli of representative samples are determined by rheological measurements.C10DAO-branched/AES aqueous mixtures form isotropic micellar solution and lamellar structures. Low viscosity was found for all these mixtures, including the most concentrated ones. In contrast, in C10DAO-linear/AES mixtures an extended hexagonal phase is detected, which presents a high viscosity. These results demonstrate tail branching and mixed aggregation to synergistically contribute to the design of high-concentration low-viscosity surfactant mixtures.

Advantages of an APS/AES Seawater-Based Surfactant Polymer Formulation

SummaryA low-complexity chemical flooding formulation has been developed for application in offshore environments. The formulation uses seawater with no additional water treatment beyond that which is normally performed for waterflooding (filtration, deoxygenation, etc.). The formulation is a mixture of an alkyl propoxy sulfate (APS) and an alkyl ethoxy sulfate (AES) with no cosolvent. With seawater only (no salinity gradient), the blend of APS and AES gives substantially higher oil recovery than a blend of APS and internal olefin sulfonate (IOS) in outcrop sandstone. This formulation also reduces complexity, increases robustness, and potentially improves project economics for onshore projects as well.It is shown that the highest oil recovery is obtained with surfactant blends that produce formulations that are underoptimum (Winsor Type I phase behavior) with reservoir crude oil. Also, these underoptimum formulations avoid the high-injection pressures that are seen with optimum formulations in low-permeability outcrop rock. The formulation recovers a similar amount of oil in reservoir rock in the swept zone. Overall recovery in reservoir rock is lower than outcrop sandstone due to greater heterogeneity, which causes bypassing of crude oil.A successful formulation was developed by first screening surfactants for phase behavior then fine tuning the formulation based on insights developed with corefloods in consistent outcrop rocks. The consistency of the outcrop is essential to understand cause and effect. Then, final floods were performed in reservoir rock to confirm that low interfacial tension (IFT) is propagated through the core.

Krafft Point Prediction of Anionic Surfactants Using Group Contribution Method: First‐Order and Higher‐Order Groups

AbstractKrafft point is one of the key properties of anionic surfactants to indicate their solubility in an aqueous phase. Below the Krafft point, the surfactant is a useless solid. We have developed a prediction model for the Krafft point based on the Marrero and Gani Group Contribution (GC) concept. Literature data were analyzed and a new third‐order level was proposed to improve the model accuracy. The Krafft points of 53 anionic surfactants were collected including alkyl sulfonate, alkyl sulfate, alkyl benzene sulfonate, alkyl ethoxy sulfate, alkyl ester sulfonate, alkyl ester sulfate, alkyl disulfate, alkyldiphenylether disulfonates, alkyl diester sulfonate, alkyl naphthalene sulfonate, and fluorocarbon surfactants. The coefficients of the fractional groups in a surfactant molecule reveal the dependence of the Krafft point on the internal structure. Compared to the more complicated models such as those based on advanced statistical concept, the GC model for the Krafft point developed in this work gives a higher accuracy with a simpler calculation.

Experimental Investigation of the Effects of Partially Hydrolyzed Polyacrylamide (PHPA) and Xanthan on Foam Stability

Foam flooding is one of the enhanced oil recovery (EOR) methods. Stability of the produced foam plays a significant role in overall efficiency of foam flooding. Polymers can be added to foam solutions to improve foam stability and enhance its characteristics. In this study the feasibility of improving foam stability by polymer addition is investigated. Alkyl Ethoxy Sulfate (AES) surfactant as the anionic surfactant and Cetyl Trimethyl Ammonium Bromide (CTAB) as the cationic surfactant are used as the foaming agents. The effects of polymer addition on foam stability is determined by the addition of different concentrations (0-3000 ppm) of PHPA and xanthan to foam solution and finally foam stability as the time taken for 80% of the foam to collapse was determined accordingly. The experimental results showed that CTAB performed better than AES as the foaming agent. Foam stability was enhanced by the addition of both PHPA and xanthan to foam solutions. Xanthan was more compatible with formation brine and PHPA was more compatible with fresh water to enhance foam stability.

A bioassay battery for the ecotoxicity assessment of soils conditioned with two different commercial foaming products

Alkylethoxysulfate (AES) surfactants are the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Huge amounts of soil debris are produced during the excavation process and their possible re-use as by-products (e.g. land covering) or discharge as waste is a critical question in civil engineering. There can be an environmental impact from the potential ecotoxicity of the residual chemical mixture occurring in the foam-conditioned excavated soil. Chemical analyses are not able on their own to assess the potential hazards for the ecosystem ascribable to inadequate management of this kind of conditioned soil. Ecotoxicological tests, on the other hand, provide useful overall information about the potential effects of conditioned debris on soil and aquatic biota, including synergic ones, whether or not there is a detailed knowledge of the chemical composition of all the components of the commercial foaming products.In this context, the objective of this work was to evaluate the overall ecotoxicity of excavated soil conditioned with two common foaming products containing sodium lauryl ether sulphate (SLES) as the main component, in order to verify their possible re-use as by-products. For this purpose, two soils with different geopedological characteristics were conditioned with the commercial foaming agents at the concentrations utilised for mechanized tunnelling and then used for microcosm laboratory experiments. Soil sub-samples were collected at different times (0, 7, 14, 28 days) of incubation and soil elutriates were produced to assess the effects of the foaming agents on five test species (Pseudokirchneriella subcapitata, Daphnia magna, Danio rerio, Vibrio fischeri and Lepidium sativum). The results of the tests were then compared with SLES residual concentrations in the elutriates, determined with the MBAS (methylene blue active substances) spectrophotometric method. Finally, the data were combined in a battery index, which proved effective at evaluating the overall ecotoxicity in a real-life situation of two different excavated soils conditioned with the two products analysed.

Design of an optimal middle phase microemulsion for ultra high saline brine using hydrophilic lipophilic deviation (HLD) method

Abstract In this work, alcohol-free surfactant formulations incorporating sodium alkyl alkoxy sulfate surfactants and a sodium alkyl ethoxy sulfate surfactant are tested at 52 °C for reservoir brine having a total dissolved solids of above 300,000 mg/L with total hardness of about 13,000 mg/L. The optimized surfactant formulations show excellent aqueous phase stability, produce an ultra-low-interfacial tension (IFT) of 0.004 mN/m, and give fast coalescence rates of less than 30 min at reservoir salinity and temperature. Surfactant-only sand pack studies further validate the formulations by mobilizing about 60% of residual oil without mobility control. In addition, the hydrophilic lipophilic deviation (HLD) method is used to find the optimal surfactant/co-surfactant ratio (defined as the ratio giving the lowest IFT) at the reservoir salinity and temperature. Results show, first, that HLD constants measure at low salinity are applicable at high salinity and high hardness, and second, that the correct determination of surfactant head constant ‘K’ and temperature constant ‘αT’ governs the precision of the HLD approach as a surfactant selection tool for chemical enhanced oil recovery (cEOR) application. Results illustrate the potential of surfactant-only flooding to produce significant tertiary oil recovery.

Foam Film Characterization of Commercial Surfactants and their Mixtures

Abstract The properties of microscopic foam films formed by two commercial surfactants, sodium alkylethoxy sulfate and linear alkylbenzene sulfonic acid as well as by their mixtures are studied. The results obtained refer to the following dependences: surface tension on surfactant concentration at three different electrolyte concentrations; film thickness on electrolyte concentration at constant surfactant concentration; film thickness on surfactant concentration at constant electrolyte concentration; disjoining pressure on film thickness (disjoining pressure isotherms). Calculated are the following physicochemical parameters: the diffuse electric layer potential, surface charge, molecule area for the respective surfactant and close packing surface concentration of the adsorption layer. The data obtained provide an option to link the model foam film experiments with the real processes and systems.

Comprehensive assessment of aquatic community responses to a new anionic surfactant, high-solubility alkyl sulfate

High-solubility alkyl sulfate (HSAS) is a new anionic surfactant for use in consumer product applications that provides enhanced water solubility and improved water hardness tolerance. A comprehensive model stream ecosystem investigation was conducted to assess ecological and toxicological effects of HSAS on stream invertebrates. Model streams were dosed with HSAS for a period of 56 days following 56 days of colonization in a single-pass, flow-through system. Exposures were control and 9.1, 24.1, 64.0, 165.8, and 426.5 μg/L based on specific analytical detection methods. Benthic abundance on gravel substrates, drift, and insect emergence were assessed. Several taxonomically unrelated taxa were found sensitive to HSAS and formed the basis of toxicological conclusions. Abundance or biomass of a limpet ( Ferrissea), a bivalve ( Corbicula), flatworms (Turbellaria), and a mayfly ( Stenonema) was reduced at concentrations ranging from 165.8 to 426.5 μg/L. Principal response curve analysis, a constrained form of principal components analysis, demonstrated consistency with univariate analyses and identified similar populations as being sensitive to HSAS. Comparison with historical studies from the same testing site, streams, and experimental design, but with structurally related alkyl sulfate and alkyl ethoxysulfate anionic surfactants, revealed several similar trends in response profiles at the population level for both tolerant and sensitive species. Based on the comprehensive nature of the study, strength of data trends, and demonstrated sensitivity of the aquatic communities contained in the experimental system, the no-observed-effect concentration for HSAS was concluded to be 64.0 μg/L. An application factor of 1 is justified for deriving a predicted no-effect concentration) for HSAS in aquatic systems.

Lauryl alcohol and amine oxide as foam stabilizers in the presence of hardness and oily soil

AbstractThe effects of two potential foam boosters, n‐dodecanol (or lauryl alcohol: LA) and tetradecyldimethylamine oxide (C14DMAO), were investigated for two situations in which foam made from a 0.01 wt% solution of a common alkylethoxy sulfate surfactant was highly unstable in the presence of oil drops consisting of an n‐hexadecane/oleic acid mixture. In one case in which dissolved CaCl2 was present at alkaline pH, insoluble calcium oleate particles formed in situ and facilitated foam breakage. In the other, a much higher concentration of calcium was present at neutral pH, and drops of a microemulsion phase formed but no calcium oleate. In both cases, 0.005 wt% LA reduced the entry coefficient, E, of the oil to the air‐water surface sufficiently to prevent drop entry and stabilized the foam. In contrast, 0.005 wt% C14DMAO caused smaller reductions in E and was ineffective as a foam booster. LA was more effective because it was able to form a more compact monolayer with the surfactant than C14DMAO at the air‐water surface, which led to lower surface tensions and hence lower values of E.

Ecological effects of an anionic C12–15AE‐3S alkylethoxysulfate surfactant in outdoor stream mesocosms

The ecological assessment of a C12-15 AE-3S linear alkylethoxysulfate (AES) anionic surfactant to invertebrates, fish, periphyton, and an aquatic macrophyte was conducted in a 30-d outdoor stream mesocosm study with five replicated concentrations and controls. Alkylethoxysulfate structural integrity and exposure concentrations were maintained during the 30-d treatment period, with average measured concentrations of 0.7, 1.27, 2.2, 4.31, and 10.18 mg/L. No effects were observed on the aquatic macrophyte Myriophyllum aquaticum at the highest concentration tested. A sevenfold increase in periphyton biomass at 10.18 mg/L was observed relative to controls primarily because of increases in density of the filamentous alga Mougeotia sp. Densities of the invertebrates Annelida (Stylaria), Amphipoda, Copepoda, Trichoptera (Hydropsychidae), Cladocera, and Diptera (Chironomidae) significantly decreased in streams treated with AES at 10.18 mg/L. Densities of drifting invertebrates were not observed to be affected at any concentration tested. Reproduction of Pimephales promelas significantly decreased at 1.27 mg/L and growth of juvenile Lepomis macrochirus was significantly affected at 4.31 mg/L. Multivariate cluster analysis and nonmetric multidimensional scaling ordination showed distinct structural effects on the invertebrate communities in the streams treated with AES at 10.18 mg/ L compared to the control and streams treated at < 10.18 mg/L through the 30-d treatment. Convergence of the communities treated at 10.18 mg/L toward control communities in the ordination suggests recovery in these communities after termination of surfactant treatment. The results from this study support an ecosystem value of > 2.0 mg/L, and indicate that the conservative Dutch risk assessment for AESs has at least a fivefold margin of safety.

Atmospheric pressure ionization mass spectrometry techniques for the analysis of alkyl ethoxysulfate mixtures

This paper compares two liquid introduction atmospheric pressure ionization techniques for the analysis of alkyl ethoxysulfate (AES) anionic surfactant mixtures by mass spectrometry, i.e., electrospray ionization (ESI) in both positive and negative ion modes and atmospheric pressure chemical ionization (APCI) in positive ion mode, using a triple quadrupole mass spectrometer. Two ions are observed in ESI(+) for each individual AES component, [M + Na] + and a “desulfated” ion [M − SO 3 + H] +, whereas only one ion, [M − Na] − is observed for each AES component in ESI(−). APCI(+) produces a protonated, “desulfated” ion of the form [M − NaSO 3 + 2H] + for each AES species in the mixture under low cone voltage (10 V) conditions. The mass spectral ion intensities of the individual AES components in either the series from ESI(+) or APCI(+) can be used to obtain an estimate of their relative concentrations in the mixture and of the average ethoxylate (EO) number of the sample. The precursor ions produced by either ESI(+) or ESI(−), when subjected to low-energy (50 eV) collision-induced dissociation, do not fragment to give ions that provide much structural information. The protonated, desulfated ions produced by APCI(+) form fragment ions which reveal structural information about the precursor ions, including alkyl chain length and EO number, under similar conditions. APCI(+) is less susceptible to matrix effects for quantitative work than ESI(+). Thus APCI(+) provides an additional tool for the analysis of anionic surfactants such as AES, especially in complex mixtures where tandem mass spectrometry is required for the identification of the individual components.

Direct and indirect ecotoxicological effects of alkyl sulfate and alkyl ethoxysulfate on macroinvertebrates in stream mesocosms

Stream mesocosm experiments were conducted with the anionic surfactants alkyl sulfate (AS) and alkyl ethoxylate sulfate (AES) to determine the ecotoxicological effect thresholds on stream communities. Autotrophic and heterotrophic periphyton, protozoan, and invertebrate population and community effect assessments were conducted over an 8-week exposure period in the summer to fall seasons following a 2- to 3-month colonization period. Concentrations spanned environmentally low to unrealistically high concentrations to challenge the sensitivity of the test system and to understand the potential array of effects. In both experiments mayfly taxa and clam populations were significantly impaired at high concentrations (582–1586 μg surfactant/l). Indirect effects, associated with increased heterotrophic periphyton biomass in surfactant-treated streams at 224–1586 μg surfactant/l, supported increased densities of oligochaetes and gastropods. Mayfly habitat may have become sub-optimal during the AS experiment as a result of the heterotrophic biofilm at concentrations above 224 μg/l. These experiments resulted in ecotoxicological no-observed-effect-concentrations (NOECs) of 224 μg AS/l and 251 μg AES/l. Structure-activity relationships would have predicted AES as 10-fold more toxic than AS. Differences between the prediction and mesocosm observations likely reflected confounding effects of heterotrophic periphyton in the AS experiment. The invertebrate community NOECs assure the existence of a margin of environmental safety for both alkyl sulfate and alkyl ethoxylate sulfate.

消費財の環境リスクアセスメント手法 直鎖アルキルベンゼンスルホン酸塩とアルキルエトキシ硫酸塩のケーススタディ

Consumer product compounds are used in the home and disposed in waste water where they typically receive waste treatment. After treatment, sludge and effluent are released to the environment resulting in the potential exposure of terrestrial and aquatic organisms, respectively, to consumer product compounds.To ensure the environmental safety of these compounds, the environmental risk posed by compounds released into the environment must be assessed. A reasonable, consistent and cost-effective method to conduct environmental risk assessments and to prioritize testing of these compounds is needed which addresses risk to organisms residing in the terrestrial and aquatic compartments of the environment. Risk is evaluated by understanding environmental fate (i.e., exposure) and effects and is quantified in the risk ratio. In addition, the potential transfers through the food web leading to concentrations in food are predicted with an estimate of bioconcentration and bioaccumulation factors. Specifics of the tiered risk assessment approach are discussed and demonstrated using two consumer product compounds : linear alkylbenzene sulfonate (LAS) and alkyl ethoxy sulfate (AES).

Immobilization of the surfactant-degrading bacterium Pseudomonas C12B in polyacrylamide gel. III. Biodegradation specificity for raw surfactants and industrial wastes

The surfactant-degrading bacterium Pseudomonas C12B was immobilized in polyacrylamide gel beads and the specificity of the immobilized cells towards various surfactants was examined. Profiles of activity towards primary alkyl sulfates of chain lengths from C 6 to C 14 were very similar for free and immobilized cells and reflected the known specificities of the alkylsulfatase enzymes that initiate the degradation. Initial rates of surfactant disappearance were in the order alkyl sulfates > linear alkyl benzene sulfonates > alkyl ethoxy sulfates ⪢ alkane sulfonates. Sulfate esters, but not sulfonates, were totally degraded within 48h. Immobilized cells also removed surfactant from solutions containing raw alkyl ethoxy sulfate mixtures (used to formulate shampoos), diluted whole-shampoo formulations, and mixed balance-tank effluent containing waste shampoo, hair dyes, and permanent wave formulations from a hair products factory. Repeated exposure to these wastes in the presence of added basal salts showed that the immobilized cells retained at least 60% and 28% of their activity after 6-day and 13-day operating periods, respectively. Balance-tank effluent, while initially producing the lowest activity, also provided the greatest stability even in the absence of added basal salts. Broad substrate specificity for sulfated surfactants, coupled with good biocatalyst stability, suggested that this system offered considerable potential for on-site treatment of surfactant wastes.

Contact Hypersensitivity and Sensitizing Mechanism of the Sultones Contaminated in Alkyl Ethoxy Sulfate Products

Contact Hypersensitivity and Sensitizing Mechanism of the Sultones Contaminated in Alkyl Ethoxy Sulfate Products

Determination of sultones in anionic surfactants

AbstractSaturated and unsaturated 1,3‐ and saturated 1,4‐sultones in anionic surfactants are identified and measured by a series of separation maneuvers. The sultones are separated from the surfactant by ion‐exchange treatment and concentrated by thin layer chromatography. By the use of high performance liquid chromatography, the sultones are identified on the basis of their retention times and are measured by comparing their peak areas with those of reference compounds. Adequate responses are obtained from 5 μg quantities of sultone, corresponding to 0.1 ppm sultone in a 50 g sample of alkylethoxy sulfate paste. All the sultones of interest are separated from each other. Chlorosultones can be determined after first treating them with collidine, which dehydrohalogenates them to the unsaturated sultones.