Surface Dilational Rheology,Foam, and Core Flow Properties of Alpha Olefin Sulfonate

The surface tension, surface dilational rheology, foaming and displacement flow properties of alpha olefin sulfonate (AOS) with inorganic salts were studied. The foam composite index (FCI), which reflects foaming capacity and foam stability, is used to evaluate foam properties. It is found that sodium and calcium salts can lead to decreases in AOS surface tension, critical micelle concentration, and molecular area at the gas–liquid interface. Sodium ions reduce the surface dilational viscoelasticity (E) and FCI of AOS, while calcium ions can enhance the E of AOS and make the FCI of AOS reach a maximum. In the solution containing calcium and sodium ions, the FCI of AOS is improved. Crude oil reduces the FCI of AOS. Injection pressure and displacing efficiency of AOS alternating carbon dioxide (CO₂) injection are higher than injections of water alternating with CO₂ or CO₂ alone in low permeability cores.     

Performance Comparison Between Internal Olefin Sulfonates and Alpha Olefin Sulfonates

Comparison of surface and interfacial properties of internal olefin sulfonates (IOS) and alpha olefin sulfonates (AOS) shows that hydrocarbon chain branching has a significant influence on interfacial properties at the air–water, pentadecane–water and parafilm–water interfaces. The isomeric branched IOS shows a higher critical micelle concentration and are more effective in reducing the surface tension at the air–water interface by occupying a larger area per molecule. IOS exhibits better dynamic air–water interfacial properties due to a lower meso-equilibrium surface tension. The equilibrium interfacial tensions for AOS and IOS have no remarkable difference at the pentadecane–water interface. The water wettability and electrolyte tolerance are enhanced with branched hydrocarbon chain olefin sulfonates.     

Aqueous Foam Stabilized by Hydrophobic SiO2 Nanoparticles using Mixed Anionic Surfactant Systems under High-Salinity Brine Condition

A primary concern of surfactant-assisted foams in enhanced oil recovery (EOR) is the stability of the foams. In recent studies, foam stability has been successfully improved by the use of nanoparticles (NP). The adhesion energy of the NP is larger than the adsorbed surfactant molecules at the air–water interface, leading to a steric barrier to mitigate foam-film ruptures and liquid-foam coalescence. In this study, the partially hydrophobic SiO₂ nanoparticles (SiO₂-NP) were introduced to anionic mixed-surfactant systems to investigate their potential for improving the foamability and stability. An appropriate ratio of internal olefin sulfonate (C_15-18 IOS) and sodium polyethylene glycol monohexadecyl ether sulfate (C₃₂H₆₆Na₂O₅S) was selected to avoid the formation of undesirable effects such as precipitation and phase separation under high-salt conditions. The effects of the NP-stabilized foams were investigated through a static foam column experiment. The surface tension, zeta potential, bubble size, and bubble size distribution were observed. The stability of the static foam in a column test was evaluated by co-injecting the NP-surfactant mixture with air gas. The results indicate that the foam stability depends on the dispersion of NP in the bulk phase and at the water–air interface. A correlation was observed in the NP-stabilized foam that stability increased with increasing negative zeta potential values (−54.2 mv). This result also corresponds to the smallest bubble size (214 μm in diameter) and uniform size distribution pattern. The findings from this study provide insights into the viability of creating NP-surfactant interactions in surfactant-stabilized foams for oil field applications.     

Alpha olefin sulfonates from a commercial SO3-Air reactor

Alpha olefin sulfonate (AOS) can be made by SO₃-air sulfonation of straight chain alpha olefins followed by saponification of the neutralized product. The sulfonation step forms unsaturated sulfonic acids, sultones and sultone sulfonic acids. Hydrolysis of the various sultones yields a mixture of unsaturated and hydroxy sulfonates. Sulfonation of commercial mixtures of straight chain alpha olefins in a large-scale SO₃ falling film unit has given AOS of 1.5–3.0% oil based on active content and tristimulus color of about 40% saturation (2% solution) which is readily bleachable with 1–3% NaOCl to about 10–15% saturation. Performance of AOS made from C₁₅−C₁₈ alpha olefin is comparable to that of the high-foaming C₁₁−C₁₄ LAS in both detergency and dishwashing foam. It is superior to similar products made from internal straight chain olefins. The product shows a low order of toxicity and biodegrad-ability slightly better than that of LAS. A C₁₅−C₁₆ AOS blend is especially attractive in liquid detergent formulations. Presented at the AOCS Meeting, Los Angeles, April 1966.     

Synthesis and Surface Properties of a Novel Sodium 3‐(3‐Alkyloxy‐3‐oxopropoxy)‐3‐oxopropane‐1‐sulfonate at the Air–Water Interface

The present paper describes the synthesis and evaluation of surface properties of a novel series of anionic surfactant, namely sodium 3‐(3‐alkyloxy‐3‐oxopropoxy)‐3‐oxopropane‐1‐sulfonate with varying alkyl chain length (C8–C16). Synthesis involves initial formation of the 3‐alkyloxy‐3‐oxopropyl acrylate along with fatty acrylate during the direct esterification of fatty alcohol with acrylic acid in the presence of 0.5 % NaHSO₄ at 110 °C followed by sulfonation of the terminal double bond of the 3‐alkyloxy‐3‐oxopropyl acrylate. Synthesized compounds were evaluated for surface and thermodynamic properties such as critical micelle concentration (CMC), surface tension at CMC (γ_cmc), efficiency of surface adsorption (pC₂₀), surface excess (Γ_max), minimum area per molecule at the air–water interface (A_min), free energy of adsorption (?G°_ads), free energy of micellization (?G°_mic), wetting time, emulsifying properties, foaming power and calcium tolerance. Effect of chain length on CMC follows the classic trend, i.e. decrease in CMC with the increase in alkyl chain length. High pC₂₀ (>3) value indicates higher hydrophobic character of the surfactant. These surfactants showed very poor wetting time and calcium tolerance, but exhibited good emulsion stability and excellent foamability. Foaming power and foam stability of C14‐sulfonate were found to be the best among the studied compounds. Foam stability of C14‐sulfonate was also studied at different concentrations over time and excellent foam stability was obtained at a concentration of 0.075 %. Thus this novel class of surfactant may find applications as foam boosters in combination with other suitable surfactants.     

AOS — An anionic surfactant system: Its manufacture,composition, properties,and potential application

Several sulfonation parameters, believed to be critical to the manufacture of good quality a-olefin sulfonate (AOS), are related to product color and conversion. The interfacial properties for single carbon number AOS and the major components comprising AOS are investigated. Results, based on surface activity, indicate that AOS in the molecular weight range from C₁₄ through C₁₈ should be of value in formulating efficient cleaning agents. The data show that AOS is more effective for lowering Crisco®/solution interfacial energy than the more commonly used surfactants. The alkene-1-sulfonate component of AOS was found to be most effective in lowering interfacial energy with the hydroxyalkane-1-sulfonate component being significantly less effective but still more effective than alcohol ether sulfate or linear alkylbenzene sulfonate of comparable molecular weight. Hand dishwashing efficacy was found greatest for the hydroxyalkane-1-sulfonate component of AOS, but combinations of hydroxyalkane-1-sulfonates and alkene-1-sulfonates were shown to be synergistic for laundering applications. The presence of the -OH group in the hydroxyalkane sulfonate structure was shown to increase solubility and lower surface activity significantly more than the presence of unsaturation in the alkene sulfonate. Long, single branching in the a-olefin sulfonate and random internal olefin sulfonate are shown to reduce drastically the surface activity. The hydroxyalkane and alkene-1-sulfonates were rapidly biodegraded. Disulfonates and long, singly branched sulfonate were more slowly degraded. Both 1,3-sultones and 1,4-sultones were found to biodegrade rapidly.     

α-烯烃磺酸盐在液体洗涤剂中的应用

介绍了采用气相三氧化硫法生产的α-烯烃磺酸钠在液体洗涤剂配方中的应用。通过正交设计说明,影响黏度的最重要因素是氯化钠的质量分数。考察了不同碳数AOS对液体洗涤剂黏度的影响以及AOS与AES复配后液体洗涤剂去污力、调黏度和泡沫性能的区别,综合应用实验结果表明,AOS适合用于液体洗涤剂中。     

内烯烃磺酸盐表面活性剂的合成与性能

以内烯烃为原料,以三氧化硫·二氧六环络合物为磺化试剂进行磺化反应,制得内烯基磺酸,经中和反应制得内烯烃磺酸盐表面活性剂;采用红外光谱对产物的结构进行了表征,结果表明产物结构与预期产物结构相符。考察了所合成的内烯烃磺酸盐表面活性剂的起泡性能和乳化性能,内烯烃磺酸盐具有良好的起泡性能和稳泡性能,以及优良的乳化性能和乳化稳定性;采用TX500界面张力对产物的界面张力进行了测定,表明所合成的新型内烯烃磺酸盐能够显著降低原油的界面张力最低降至(0.000 7 mN/m),具有很高的界面活性。     

Performance of alpha olefin sulfonates derived from ziegler olefins in light duty liquid detergents

Single carbon number olefins derived from Ziegler technology were sulfonated in a continuous fallingfilm SO₃ reactor. The resulting alpha olefin sulfonate (AOS) was evaluated in a dishwashing test at several water hardnesses. Statistical analysis of the data led to the selection of compositions suitable for hand dishwash applications. AOS, prepared by sulfonating a blend of C₁₄ and C₁₆ olefins, was evaluated for hand dishwashing efficiency in a ternary mixture consisting of AOS, an alcohol ether sulfate and monoethanolamide. Regression equations calculated from the data permit the prediction of performance levels for all practical combinations of the three ingredients. The effect of unreacted olefin on AOS dishwash performance was also determined. With a binary blend of AOS and monoethanolamide it was shown that up to 5% free oil (based on AOS active) could be tolerated without significant deleterious effect.     

α—烯烃磺酸盐的性能及其应用研究

测定和研究了α -烯烃磺酸盐 (AOS)与其它表面活性剂复配体系的粘度、起泡力、稳泡度等特性 ,并用正交实验法对以AOS为主体表面活性剂的香波、沐浴露等个人洗护用品配方进行了研究。     

High pressure liquid chromatography of alpha olefin sulfonates

Alpha olefin sulfonates (AOS) are a complex mixture of the posi-tional isomers of hydroxyalkane sulfonates, alkene sulfonates, and disulfonates. This paper describes a qualitative method for separat-ing these various components by reverse-phase high pressure liquid chromatography. The column utilized was a DuPont Zorbax TMS (4.6 mm × 25 cm) with a water/methanol (25:75, v/v) mobile phase containing sodium nitrate at a concentration of 0.4M. The hydroxyalkane sulfonate and alkene sulfonate peaks were identified using laboratory prepared standards. The disulfonate peaks were located using controlled sulfonation conditions. More work needs to be done to separate an overlap of C₁₆ 3-hydroxyalkane sulfonate and C₁₄ 2-alkene sulfonate in 1416 AOS. However, if studies are based on single carbon number AOS samples, the overlap of these peaks can be avoided. This method can be utilized as a qualitative tool for the comparison of sulfonation runs, the identification of AOS within a detergent, or the identfication of the olefin type used for sulfonation.     

Analysis of the Effects of Hydrocarbon Chain on Foam Properties of Alkyl Polyglycosides

The influence of surfactant structure on foam properties of different alkyl polyglycosides (APGs) in aqueous solutions was studied. Foamability, foam stability, and foam morphology were analyzed using the FoamScan method. Results showed that the foamability, foam stability, and the liquid carrying ability of long-chain APGs are higher than those of short-chain APGs. Foam morphology analysis showed that the foam produced by short-chain APGs is more unstable than the foam generated by long-chain APGs. Long-chain APGs have stronger intermolecular cohesion force, stringency, and ductility than short-chain APGs.     

The mixed surfactant system of linear alkylbenzene sulfonate and alpha olefin sulfonate

Physicochemical and detergency studies on the mixed surfactant system of linear alkylbenzene sulfonate-sodium salt (LABS) and alpha olefin sulfonate-sodium salt (AOS) have been carried out. The binary surfactant system exhibits minima in the surface tension and in the critical micelle concentration when the two surfactants are present in the ratio 80:20, indicating synergism in the mixed monolayer and in mixed micelles at this proportion of the two surfactants. The mixed micelles improve hard-water tolerance of LABS and reduce the loss of LABSvia Ca(LABS)₂ precipitation. Addition of AOS to LABS improves its lime soap dispersion properties. The effect is highly significant when AOS is present at the 20% level in the mixed surfactant system. A synergistic mixture of the two surfactants, when used in phosphate-free, carbonate-built detergent product formulation, exhibits superior detergency, low ash deposit and better stainremoving ability when compared to products containing LABS as the sole active surfactant.     

Kinetic Approach by Photocurrent Measurements to the Photoelectrocatalytic Oxidation of an Anionic Surfactant Using an S,N-TiO2/Ti Electrode: Distinguishing Between Direct and Indirect Mechanisms

The photoelectrocatalytic oxidation of an anionic surfactant (internal olefin sulfonate C20-C24, IOS) in synthetic oilfield wastewater was investigated by photocurrent measurements using a sulfur and nitrogen co-doped titanium dioxide electrode (S,N-TiO₂/Ti). For the electrode preparation, S,N-TiO₂ films were supported on Ti expanded meshes by sol–gel dip-coating, followed by thermal treatment at 400 °C. Photocurrent measurements were performed by linear sweep voltammetry (LSV) under UV–Vis irradiation using different IOS concentrations (20–200 ppm). The photocurrent values obtained at 0.5 V vs Ag/AgCl (i_ph) for each IOS concentration (C_IOS) were used to plot the 1/i_ph vs 1/C_IOS graph, in which two trends were identified. For high IOS concentrations (70–200 ppm), the values fitted well to the unimolecular Langmuir–Hinshelwood (LH1) kinetic model (R²?=?0.973), which can be associated with the direct oxidation mechanism. For low IOS concentrations (20–70 ppm), the values fitted better to a linear combination of both unimolecular and bimolecular Langmuir–Hinshelwood (LH1 and LH2) kinetic models (R²?=?0.854), which can be associated with direct and indirect oxidation mechanisms, respectively. These results suggest that at high IOS concentrations the IOS adsorption plays the main role on the photoelectrocatalytic oxidation, while at low IOS concentrations both IOS adsorption and H₂O adsorption (surface hydrophilicity) play important roles on the photoelectrocatalytic oxidation.

     

Use of high-active alpha olefin sulfonates in laundry powders

Alpha olefin sulfonates (AOS) have been used successfully for many years in laundry and personal-care products throughout Asia. Among their documented positive attributes are good cleaning and high foaming in both soft and hard water, rapid biodegradability, and good skin mildness. AOS has commonly been marketed as approximately 40%-active aqueous solutions. However, with the increased importance of compact powder detergents produced by processes other than spray drying, high-active forms of AOS including 70%-active pastes and 90+%-active powders are now being utilized for that product sector. In this regard, the rheological properties of non-Newtonian AOS and AOS/additive pastes at relevant process temperatures were measured and found potentially suitable for agglomeration processes. Also, the relationship of AOS powder particle size to surfactant solubility at various wash conditions was examined to allow determination of the optimal size for both detergency and processing of laundry powders. Both paste rheology and powder morphology are critical factors for the successful use of high-active AOS in compact powder detergents.     

Precipitation of anionic surfactants in the presence of sodium oleate and calcium ions

Precipitation of anionic surfactants, linear alkylbenzene sulfonate (LAS) and alpha olefin sulfonate (AOS), by calcium ions was studied in the presence of sodium oleate. Lather stability was determined by the Ross-Miles method, precipitation was followed by measuring the optical density (OD), and equilibrium surface tension (EST) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the nature of the precipitate formed. For the 5 mM LAS-0.7 mM oleate system, lather was unstable, and the OD was high in the 2–5°FH region of calcium hardness, while at higher calcium hardness levels, lather was stable and the turbidity of solutions decreased. On the other hand, in the 5 mM AOS-0.7 mM oleate system, lather was unstable throughout the calcium hardness region studied (0–20°FH). Also, the turbidity build-up was much higher in the AOS system than in the LAS system. Analysis of the precipitates formed in these systems by FTIR spectroscopy indicated that the precipitate from the AOS system had an additional band at 1190 cm⁻¹, corresponding to the sulfonate group. These results, together with the EST data, confirm that the precipitate formed in the LAS system between 2–5°FH calcium is calcium oleate, and that formed in the AOS system is likely to be calcium (AOS) oleate. It is tempting to hypothesize that the similarity of AOS and oleate in chainlength could be responsible for the coprecipitation of AOS and oleate with calcium, whereas LAS, which has a larger headgroup with a benzene ring and two smaller chains (average length is C8) is unlikely to precipitate with the oleate.     

Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

In foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 °C, salinity of 6778 mg L⁻¹, pH = 8–9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200–500 L s) and low oil tolerance index (0.1–0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half-life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C₁₆HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative β^s parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.     

Performance and Efficiency of Anionic Dishwashing Liquids with Amphoteric and Nonionic Surfactants

Performance and efficiency of anionic [sodium lauryl ether sulfate (SLES) and sodium α-olefin sulfonate (AOS)] and amphoteric [cocamidopropyl betaine (CAB)] as well as nonionic [cocodiethanol amide (DEA), various ethoxylated alcohols (C₁₂–C₁₅–7EO, C₁₀–7EO and C₉–C₁₁–7EO) and lauramine oxide (AO)] surfactants in various dishwashing liquid mixed micelle systems have been studied at different temperatures (17.0, 23.0 and 42.0 °C). The investigated parameters were critical micelle concentration (CMC), surface tension (γ), cleaning performance and, foaming, biodegradability and irritability of anionic (SLES/AOS) and anionic/amphoteric/nonionic (SLES/AOS/CAB/AO) as well as anionic/nonionic (SLES/AOS/DEA/AO, SLES/AOS/C₁₂-C₁₅-7EO/AO, SLES/AOS/C₁₀–7EO/AO and SLES/AOS/C₉–C₁₁–7EO/AO) dishwashing surfactant mixtures. In comparison to the starting binary SLES/AOS surfactant mixture, addition of various nonionic surfactants promoted CMC and γ lowering, enhanced cleaning performance and foaming, but did not significantly affect biodegradability and irritability of dishwashing formulations. The anionic/nonionic formulation SLES/AOS/C₉–C₁₁–7EO/AO shows both the lowest CMC and γ as well as the best cleaning performance, compared to the other examined dishwashing formulations. However, the results in this study reveal that synergistic behavior of anionic/nonionic SLES/AOS/ethoxylated alcohols/AO formulations significantly improves dishwashing performance and efficiency at both low and regular dishwashing temperatures (17.0 and 42.0 °C) and lead to better application properties.     

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions II: Continuous Mode of Operation

Abstract

The objective of this study was to investigate the relationship between interfacial tension (IFT) and foam characteristics and the efficiency of diesel oil removal from water in a continuous froth flotation column. The effects of operational parameters, including surfactant concentration, salinity, oil-to-water ratio, foam height, air flow rate, and hydraulic retention time (HRT) on the oil removal were investigated in the continuous mode of a froth flotation operation and compared to batch operation results. Unlike the batch system, for the continuous system used in the present study, having only branched alcohol propoxylate sulfate sodium salt surfactant (C_14–15(PO)₅SO₄Na) and NaCl present in the solution yielded such poor foam characteristics that a stable froth which overflowed the flotation column could not be produced, so the addition of sodium dodecyl sulfate (SDS) as a froth promoter was used to improve the foam stability. Unlike the batch froth flotation system with only C_14–15(PO)₅SO₄Na, the continuous froth flotation with the mixture of C_14–15(PO)₅SO₄Na and SDS, it was not possible to find a SDS and a NaCl concentration at which both ultralow IFT and good foaming were both achieved. Foam formation, stability, and production rate were found to be crucial parameters to the froth flotation efficiency. The continuous froth flotation system offers a high diesel oil removal of 96% in the single stage unit. Demonstration of efficient operation in the continuous mode in this work is important to the practical application of froth flotation in large scale processing.     

Experimental investigation and modelling of CO2-foam flow in heavy oil systems

In this work, the C_14-16 alpha olefin sulphonate (AOS) surfactant, octylphenol ethoxylate (TX-100), and methyl bis[Ethyl(Tallowate)]-2-hydroxyethyl ammonium methyl sulphate (VT-90) surfactant were selected as representatives of anionic, nonionic, and cationic surfactant to stabilize foam. The effects of surfactant concentration and gas/liquid injection rates on foam performance were examined by performing a series of oil-free foam flow tests by injecting CO₂ and a foaming surfactant simultaneously into sandpacks. Foam flooding was conducted as a tertiary enhanced oil recovery (EOR) method after conventional water flooding and surfactant flooding. Furthermore, a new method was proposed to determine the residual oil saturation. The foam stability in the presence and absence of heavy oil was studied by a comparative evaluation of the mobility reduction factor (F_MR) in both cases. The foam fractional flow modelling by Dholkawala and Sarma^[36] was modified based on experimental results obtained in this study. The range of the ratio of two important model parameters (C_g/C_c) at various foam qualities was determined and could be used for large-scale predictions. The results showed that during the oil-free foam displacement experiments higher foam apparent viscosities () were attained at lower gas flow rates and the maximum was attained at a total gas and liquid injection rate of 0.25 cm³/min with a gas fractional flow ratio of 0.8 for the foam in the absence of oil. The presence of oil reduced the foam mobility reduction factors (F_MR) to different degrees with F_MR-_{without oil} / F_MR-_{with oil} ranging from 4.25–13.69, indicating that the oil had a detrimental effect on the foam texture. The foam flooding successfully produced an additional 8.1–21.52 % of OOIP, which can be attributed to the combined effect of increasing the pressure gradient and oil transporting mechanisms.