Ethoxylated Amine Surfactants Research Articles

Effects and mitigation of poor water quality on herbicide performance: A review

AbstractSpray water quality parameters such as hardness, pH, alkalinity, turbidity, and total dissolved solids (TDS) can influence the performance of herbicides. Polyvalent cations found in hard water can reduce the efficacy of post‐emergence herbicides that are weak acids. Various approaches have been proposed to mitigate the negative effects of spray water properties on herbicide performance. Water conditioning adjuvants are designed for overcoming the adverse effects of hard water. One group of adjuvants are nitrogen containing compounds such as ammonium sulfate (AMS). The ability of AMS to overcome hard water antagonism is well‐documented but the positive effect of other ammonium compounds are variable and depend on herbicides and weed species. Other adjuvant groups that can overcome effects of poor spray quality are ethoxylated amine surfactants, organic acids and ethylenediaminetetraacetic acid (EDTA). Water quality is poor in many parts of the world, and accordingly, the study of water property effects on herbicide performance is needed to optimize use, and prevent overuse, of herbicides.

Insights into CO2 Foaming Behavior of Ethoxylated Amines

Switchable ethoxylated amine surfactants are readily soluble in CO2 and high-saline brines. The objective of the current work is to maximize the foamability and stability of CO2 foam at 150 °F (65 °C) through adjustments in the surfactant concentration, pH, and brine salinity. From the results, the authors recommend potential applications of Ethomeen C12 (EC12) for CO2 foam in the oil/gas industry. Foam stability tests helped determine the optimum parameters for CO2 foam stability at 77 °F (25 °C) and 150 °F (65 °C). The surface tension of EC12 as a function of concentration was evaluated using a drop-shape analyzer. Maximum foam stability was observed for a solution comprising of 1.5 wt% EC12, 25 wt% NaCl, and pH 6.5 at 150 °F (65 °C). The interactions with the salts allowed closer packing of the surfactant molecules at the lamellae and strengthening the foam. At a pH of 2.5, the absence of salt led to poor foam stability. However, at the same pH and in the presence of sodium chloride, the foam was stable for longer periods of time due to the salt influence. The surface tension gradients had a direct relationship to foam stability. There was a strong resistance to foam degradation when multivalent ions were present with the surfactant.

CO2 in water foam stabilized with CO2-dissolved surfactant at high pressure and high temperature

The CO2 flooding is a popular method for enhanced oil recovery, even though viscous fingering and gravity override always reduce the displacement efficiency. Foam agent can improve the gas sweep efficiency depending on foamability and foam stability, but harsh conditions destroy foam performance seriously. In this paper, tallow ethoxylated amine surfactants are used to generate and stabilize CO2 foam at high pressure and high temperature. Meanwhile, the surfactant solubility in CO2, aqueous phase behavior, bulk foam stability and apparent viscosity in porous media were presented in detail. C16-18N(EO)5 can be soluble easily in CO2 with low cloud pressure and solubility comes up to 0.5 wt% without co-solvents, which is much higher than CMC and enough for stabilize foam at 20 MPa and 80 °C. High pressure and temperature is favorable for surfactant solubility in CO2 from the cloud pressure results and protonated quaternary amine group can ensure C16-18N(EO)x dissolved in high salinity brine saturated with CO2 at 120 °C. From the results of bulk foam half-life, the foam stability stabilized with C16-18N(EO)5 was better than C12-14N(EO)5 at same conditions and higher salinity could enhance foam stability since counter irons decrease repulsion of surfactant head groups. In porous media, high foam apparent viscosities, up to 120 mPa s at 80–90% foam quality, demonstrated the tallow ethoxylated amine would be an alternative foam agent at high pressure and high temperature. Strong foam can form with fewer injecting volume when surfactants were injected with CO2 phase, ensure the surfactants could utilize more efficient to stabilize foam. Therefore, injecting C16-18N(EO)5 into underground with CO2 phase would be useful method to decrease gas mobility with forming stable foam in situ with residual water in reservoir.

Experimental Investigation of Amine-Surfactant CO2 Foam Stability Enhanced by Silica Nanoparticles

The CO2 foam generated by the conventional surfactants usually does not show long-term stability due to the substantial solubility and diffusivity of CO2 in water. Silica nanoparticles with different wettability and high adsorption energy on the gas–water interface can be used as a stabilizer to enhance the stability of the CO2 foam. In this study, nine kinds of nonionic amine surfactants were employed to generate the CO2 foam, while three kinds of silica nanoparticles were selected and added to improve the CO2 foam stability. The influences of various factors, including pressure, temperature, pH, surfactant, and nanoparticle, on the CO2 foam stability have been investigated. The experimental results show that without nanoparticles, the CO2 foam stability decreases with the increase of the number of EO groups in the ethoxylated amine surfactant, especially under high-temperature and high-pressure (HTHP) conditions. In general, the nanoparticles with a low concentration (<0.5 wt %) have little influence on the CO2 foam stability, but when the concentration of nanoparticle is enhanced high enough (1.0 wt %), the CO2 foam stability can be improved significantly. In particular, by adding 1.0 wt % nanoparticle of QS-150 to 0.5 wt % surfactant of C18N(EO)2/10, the CO2 foam stability has been increased 5–6 times, while the volume of generated CO2 foam has been increased by 17–31%. Therefore, in this study, the synergetic mechanisms between the amine surfactants and the silica nanoparticles to generate and stabilize CO2 foam have been identified.

Laboratory Study of CO2 Foam Flooding in High Temperature, High Salinity Carbonate Reservoirs Using Co-injection Technique

In this research, an ethoxylated amine surfactant is co-injected with CO2 in a series of coreflooding experiments at typical Middle Eastern reservoir conditions of high temperature, high salinity, and in situ foam is generated to reduce gas mobility in the absence of oil. The effects of reservoir permeability, injection rates, and foam quality on mobility reduction factor (MRF) and apparent viscosity of foam are discussed. In the absence of oil, an optimum foam quality of 80% is obtained using 1 wt % of surfactant solution. Shear thinning foams with viscosities ranging between 0.9 and 2.4 cP were formed at all velocities tested in this study. MRFs of 50 and 70 were obtained, respectively, in 70 and 240 mD cores at 80% foam quality, confirming that foam strength increases with increasing rock permeability. After determination of optimum foam quality and flow rate, a final coreflooding experiment was conducted in the presence of oil to quantify the effect of oil presence on foam generation and to observe th...

Phase behavior and interfacial properties of a switchable ethoxylated amine surfactant at high temperature and effects on CO2-in-water foams

The interfacial properties for surfactants at the supercritical CO2–water (C–W) interface at temperatures above 80°C have very rarely been reported given limitations in surfactant solubility and chemical stability. These limitations, along with the weak solvent strength of CO2, make it challenging to design surfactants that adsorb at the C–W interface, despite the interest in CO2-in-water (C/W) foams (also referred to as macroemulsions). Herein, we examine the thermodynamic, interfacial and rheological properties of the surfactant C12–14N(EO)2 in systems containing brine and/or supercritical CO2 at elevated temperatures and pressures. Because the surfactant is switchable from the nonionic state to the protonated cationic state as the pH is lowered over a wide range in temperature, it is readily soluble in brine in the cationic state below pH 5.5, even up to 120°C, and also in supercritical CO2 in the nonionic state. As a consequence of the affinity for both phases, the surfactant adsorption at the CO2–water interface was high, with an area of 207Å2/molecule. Remarkably, the surfactant lowered the interfacial tension (IFT) down to ∼5mN/m at 120°C and 3400 psia (23MPa), despite the low CO2 density of 0.48g/ml, indicating sufficient solvation of the surfactant tails. The phase behavior and interfacial properties of the surfactant in the cationic form were favorable for the formation and stabilization of bulk C/W foam at high temperature and high salinity. Additionally, in a 1.2 Darcy glass bead pack at 120°C, a very high foam apparent viscosity of 146 cP was observed at low interstitial velocities given the low degree of shear thinning. For a calcium carbonate pack, C/W foam was formed upon addition of Ca2+ and Mg2+ in the feed brine to keep the pH below 4, by the common ion effect, in order to sufficiently protonate the surfactant. The ability to form C/W foams at high temperatures is of interest for a variety of applications in chemical synthesis, separations, materials science, and subsurface energy production.

Switchable Nonionic to Cationic Ethoxylated Amine Surfactants for CO2 Enhanced Oil Recovery in High-Temperature, High-Salinity Carbonate Reservoirs

Summary To improve sweep efficiency for carbon dioxide (CO2) enhanced oil recovery (EOR) up to 120°C in the presence of high-salinity brine (182 g/L NaCl), novel CO2/water (C/W) foams have been formed with surfactants composed of ethoxylated amine headgroups with cocoalkyl tails. These surfactants are switchable from the nonionic (unprotonated amine) state in dry CO2 to cationic (protonated amine) in the presence of an aqueous phase with a pH less than 6. The high hydrophilicity in the protonated cationic state was evident in the high cloudpoint temperature up to 120°C. The high cloud point facilitated the stabilization of lamellae between bubbles in CO2/water foams. In the nonionic form, the surfactant was soluble in CO2 at 120°C and 3,300 psia at a concentration of 0.2% (w/w). C/W foams were produced by injecting the surfactant into either the CO2 phase or the brine phase, which indicated good contact between phases for transport of surfactant to the interface. Solubility of the surfactant in CO2 and a favorable C/W partition coefficient are beneficial for transport of surfactant with CO2-flow pathways in the reservoir to minimize viscous fingering and gravity override. The ethoxylated cocoamine with two ethylene oxide (EO) groups was shown to stabilize C/W foams in a 30-darcy sandpack with NaCl concentrations up to 182 g/L at 120°C and 3,400 psia, and foam qualities from 50 to 95%. The foam produces an apparent viscosity of 6.2 cp in the sandpack and 6.3 cp in a 762-μm-inner-diameter capillary tube (downstream of the sandpack) in contrast with values well below 1 cp without surfactant present. Moreover, the cationic headgroup reduces the adsorption of ethoxylated alkyl amines on calcite, which is also positively charged in the presence of CO2 dissolved in brine. The surfactant partition coefficients (0 to 0.04) favored the water phase over the oil phase, which is beneficial for minimizing losses of surfactant to the oil phase for efficient surfactant usage. Furthermore, the surfactant was used to form C/W foams, without forming stable/viscous oil/water (O/W) emulsions. This selectivity is desirable for mobility control whereby CO2 will have low mobility in regions in which oil is not present and high contact with oil at the displacement front. In summary, the switchable ethoxylated alkyl amine surfactants provide both high cloudpoints in brine and high interfacial activities of ionic surfactants in water for foam generation, as well as significant solubilities in CO2 in the nonionic dry state for surfactant injection.

SUGAR-BASED ETHOXYLATED AMINE SURFACTANTS AS DEMULSIFIERS FOR CRUDE OIL EMULSIONS: 2- DEMULSIFICATION OF DIFFERENT TYPES OF CRUDES

The present work studies demulsification of two types of crude oil emulsions by nine sugar-based ethoxylated amine surfactants. The effect of pH and salinity of aqueous phase of crude oil on emulsion stability was considered, and the correlation between demulsification rate and the type of crude was studied. Nine sugar-based ethoxylated amine surfactants were tested as demulsifiers for light and heavy crudes at different aqueous phase conditions. It was found that the light crude was more easily demulsified than the heavy crude. The experimental data showed that changes in pH or salinity of the aqueous phase of the emulsion enhance its stability and decrease the demulsification efficiency of the applied demulsifiers. Also, it has been shown that surfactants based on glucose octyl amine ethoxylates (GO) are the most effective in demulsifying the investigated emulsions. The data reveal that maximum demulsification efficiency is attained at a neutral pH whereas it decreases in both directions for either of the investigated crude oils. Furthermore, the results indicate that the percentage of water separation decreases as the salinity of the emulsion’s aqueous phase increases. Light crudes showed better demulsification than heavy crudes under any test condition. The demulsification process for selected emulsions was monitored by optical microscopy.

Physico-chemical properties of heavy crude oil-in-water emulsions stabilized by mixtures of ionic and non-ionic ethoxylated nonylphenol surfactants and medium chain alcohols

This work describes the formulation and evaluation of concentrated, heavy oil-in-water emulsions stabilized by mixtures of ethoxylated surfactants and normal alcohols. The rheology, stability and droplet size of these emulsions were investigated as functions of the emulsification process parameters. The parameters investigated for this study include emulsifier agent composition, presence of additives, pH and salinity of the continuous aqueous phase, emulsification temperature, oil content and emulsion aging. The produced emulsions had viscosities ranging from 30 to 150 mPa s and represent a 30-fold reduction of the crude oil viscosity. Sauter mean diameters of the droplets ranged from 10 to 50 μm. The emulsions were produced by mixing the oil with an aqueous solution containing medium normal-chain alcohols and small quantities of a mixture of ethoxylated nonylphenol and ethoxylated amine surfactants. The presence of these alcohols led to a sharp decrease in the droplet size of the emulsion. This size decrease had a direct impact on the emulsions’ stability and apparent viscosity. The rheological parameters of the aged emulsions were also essentially constant over a 42-day period.

Surface Properties and Thermodynamic Parameters of Some Sugar‐Based Ethoxylated Amine Surfactants: 1—Synthesis, Characterization, and Demulsification Efficiency

AbstractSeveral ethoxylated sugar‐based amine surfactants have been synthesized and characterized by IR and 1HNMR spectroscopy. The surface activity of the prepared compounds has been thoroughly studied and some of their surface properties (such as CMC, Γmax, and Amin) have been calculated. The surface properties of the prepared compounds were correlated to their chemical structure. It was found that CMC decreases when increasing the molecular weight of polyethylene glycols, whereas Amin increases. Furthermore, the thermodynamic parameters of adsorption and micellization were also calculated. They include ΔG, ΔH, and ΔS of micellization and adsorption. The data show that the synthesized surfactants favor adsorption, so that they can be used as demulsifiers for crude oil emulsions. In this respect, the demulsification test was carried out and the results of demulsification efficiency were correlated to the chemical composition of the investigated compounds. Some factors that affect the demulsification efficiency were also considered.

Use of surfactants to remove water-based inks from plastic film: effect of calcium ion concentration and length of surfactant hydrophobe

Effective plastic film deinking could permit the reuse of recycled polymer to produce clear film, reduce solid waste for landfills, reduce raw material demand for polymer production, and aid process economics. In this study, the deinking of a commercial polyethylene film printed with water-based ink was studied using surfactants in the presence of hardness ions (calcium ions) at various pH levels. The electrostatic properties of ink particles in a washing bath were also investigated. Synthetic anionic surfactant or fatty acid soap in the presence of calcium ions at alkaline pH levels was found to be nearly as effective at deinking as cationic, nonionic, or amphoteric surfactants alone. However, adding calcium ions decreases the deinking effectiveness of cationic, nonionic, and amphoteric surfactants. Increasing the length of the ionic surfactant hydrophobe enhances deinking. Zeta potential measurements showed that water-based ink particles in water reach the point of zero charge (PZC) at a pH of about 3.6, above which ink particles are negatively charged, so cationic surfactant tends to adsorb better on the ink than anionic surfactant above the PZC in the absence of calcium. As the cationic surfactant concentration is varied between 0.005 and 25 mM, the zeta potential of the ink particles reverses from negative to positive owing to adsorption of cationic surfactant. For anionic surfactants, added calcium probably forms a bridge between the negatively charged ink and the negatively charged surfactant head groups, which synergizes adsorption of the surfactant and aids deinking. In contrast, calcium competes for adsorption sites with cationic and nonionic surfactants, which inhibits deinking. All the surfactants studied here disperse ink particles effectively in the washing bath above pH 3 except for the ethoxylated amine surfactant.

Glyphosate Response to Calcium, Ethoxylated Amine Surfactant, and Ammonium Sulfate1

Calcium ion in the spray water can reduce glyphosate efficacy. Ammonium sulfate (AMS) is commonly added to the spray tank to overcome the reduced efficacy. However, it is sometimes claimed that ethoxylated tallow amine surfactant (EA) is also efficacious, provided that calcium concentration is moderate (= 5 mM, 200 ppm). On response curves of ‘Plaisant’ barley treated with glyphosate, the presence of calcium ion increased the glyphosate dose needed to obtain 50% (ED50) barley growth reduction. The addition of AMS to the spray tank overcame the antagonistic effect of the calcium ion and restored glyphosate efficacy. EA was less effective than AMS at 5 or 10 mM calcium ion concentration as measured by ED50. However, at 90% growth reduction (ED90), EA was more effective than AMS at the 5 mM calcium ion concentration but less effective at the 10 mM concentration. Hence, at a moderate (= 5 mM) calcium concentration, EA would be an effective adjuvant. Calcium ion decreased the foliar uptake of glyphosate but di...

Adsorption of an Ethoxylated Amine Surfactant on Mica and Its Effect on the Surface Forces

The adsorption of tetraoxyethylene dodecylamine (C 12NHE 4) on mica and its effect on the interparticle forces between negatively charged muscovite mica surfaces has been studied employing the surface force technique. The pH of the solution has a decisive influence on the amount adsorbed, the structure of the adsorbed layer, and the interparticle forces. The main parameters which determine the structure of the adsorbed C 12NHE 4 layer are the area per lattice charge compared to the size of the molecule, the affinity between the polar group and the surface, and the affinity between the polar group and water. Below a pH of about 8 the positively charged ammonium group binds electrostatically and a surfactant monolayer is formed on each surface. At a surfactant concentration of 10 -4 M (a factor of 4 below the cmc) the surfaces are nearly uncharged. The attractive force between the monolayer coated surfaces is of a magnitude similar to the expected van der Waals force. At a pH value of 9-10 the majority of the surfactants are uncharged. Consequently, the head-group repulsion decreases, and, at a surfactant concentration of 10 -4 M, an uncharged bilayer builds up on each surface. At short separations a steric force/hydration force arises from compression and dehydration of the polar groups that are directed toward the solution. At even higher pH values the affinity between the polar group and the surface decreases, resulting in a disordered adsorbed layer. A repulsive electrostatic double-layer force dominates at large distances, and a steric force/hydration force is present at short surface separations. As the pH is lowered again the outer layer desorbs, which results in a reappearance of a strong attractive force at short separations.

Glyphosate Toxicity to Common Milkweed and Hemp Dogbane as Influenced by Surfactants

Surfactants were evaluated in the greenhouse for their ability to enhance glyphosate [N-(phosphonomethyl) glycine] toxicity to common milkweed (Asclepias syriacaL.) and hemp dogbane (Apocynum cannabinumL.). Ethoxylated amines were among the most effective groups of surfactants. Nonionic ether and ester ethoxylates combined with a dimethyl amine or a quaternary ammonium salt were more effective than any of these surfactants alone. Effectiveness of ethoxylated amine surfactants was altered by pH changes. Cat-ionic surfactants tended to be more effective than nonionic surfactants. With exceptions, surfactants were more effective with increased ethoxylation. Amine surfactant effectiveness increased with increasing concentrations up to 0.3% (w/v). Surfactant effectiveness on a molar basis was more closely related to the ethylene oxide content of the surfactant than was effectiveness on a percentage basis. Contact angle was not related to surfactant effectiveness at high or low surfactant concentrations. Ethoxylated stearyl ether and amine surfactants gave optimum effectiveness at hydrophile-lipophile balance (HLB) values of 15 to 16 and 19 to 20, respectively. Surfactants with a low HLB were usually less effective. Effectiveness of surfactant combinations was quite variable and difficult to predict. Therefore, the indiscriminate addition of surfactants to glyphosate spray mixtures which already contain a surfactant should be avoided.