Amine Oxide Surfactants Research Articles

Amine oxide surfactant-mediated synthesis of plate-based gold nanocrystals with tunable surface wrinkles and their applications in the ethylene glycol oxidation reaction

Gold nanoplates with tunable surface wrinkles are prepared using an amine oxide surfactant, showing improved EGOR activity due to enriched uncoordinated active sites.

Ecofriendly Viscoelastic Solutions Formed from a Recyclable Rosin-Based Amine Oxide Surfactant.

Innovations in molecular structures formed using bioresources are efficient means to prepare surfactant aggregates with unique properties. Here, a rosin-based amine oxide surfactant (R-11-3-AO) containing large hydrophobic groups was synthesized from rosin derivatives, namely, dehydroabietic acid and long-chain amino acids. Cryo-transmission electron microscopy showed that R-11-3-AO molecules formed extremely long wormlike micelles with a cross-sectional diameter of 4-5 nm at a concentration of approximately 7 mmol·L-1. A gel-like system was obtained at approximately 30 mmol·L-1 due to the dense entanglement of the wormlike micelles. The solutions also exhibited unique shear thickening behavior at a shear rate of approximately 10 s-1 even at high concentrations. The large hydrophobic group contained in R-11-3-AO is the origin of the strong van der Waals interactions between the surfactant molecules, resulting in the rapid growth of wormlike micelles. This rosin-based surfactant is the first recoverable amine oxide surfactant from solutions through the salting-out effect with high recovery rates. This work demonstrates the unique capabilities of rosin-based surfactants for forming wormlike micelles and provides opportunities for the development of surfactant recovery technologies.

Rheological behavior of a novel fracturing fluid formed from amine oxide surfactants

AbstractIn this paper, two kinds of long‐chain amine oxide surfactants, erucamidopropyl dimethylamine oxide (EAOS) and oleamidopropyl dimethylamine oxide (OAOS) were synthesized and compounded with different mass ratios. The rheological tests show that there is a synergistic effect between EAOS and OAOS, and this effect reaches the strongest at the EAOS/OAOS solution with α = 0.7 (α is the mass fraction of EAOS in the mixed surfactant). Through the synergistic effect between EAOS and OAOS, the temperature resistance of amine oxide surfactant solutions can be effectively improved. EAOS/OAOS (α = 0.7) solutions with total surfactant mass fractions of 3, 4, and 5 wt% show good high‐temperature resistance at 130, 140, and 150°C, respectively. After shearing for 60 min at 100 s−1, 160°C, the remaining viscosity of the 5 wt% EAOS/OAOS (α = 0.7) with 1 wt% KCl solution is 30 mPa s, meeting the demand of viscoelastic surfactant fracturing fluids.

An HLD framework for cationic ammonium surfactants

The Hydrophilic-Lipophilic Difference (HLD) model can be described by additive contributions accounting for the effect of the oil and surfactant nature, temperature, ionic strength, and so on. The first step to build an HLD framework for a surfactant class is to have Winsor III phase equilibria in a restricted range of formulation variables. In this respect, anionic and nonionic surfactants are well suited for an HLD study. On the contrary, it is difficult achieve for pure cationic surfactant Winsor III phase equilibria without the addition of alcohols and this has precluded the extension of the HLD to cationic surfactants. In the present contribution, we first propose a system based on a blend of single-tailed and double-tailed cationic surfactant to study the oil contribution, and then we afforded the determination of the surfactant contribution trough an experimental approach (the “HLD-titration”) that is especially tailored for systems displaying a wide range of existence of Winsor III phase equilibria. HLD-titration results confirmed the ionic strength contribution to HLD as a logarithmic function of salinity for cationic-based microemulsions similarly to anionic ones. However, the oil carbon number contribution is almost four-fold larger ( k ​= ​0.7 ​± ​0.1) with respect to anionic surfactants. A clearing point was observed in correspondence of the Winsor III phase equilibria under stirring. This approach allows us the determination of the so-called characteristic curvature ( Cc ), i.e. the term describing the surfactant nature contribution to the film curvature, of the cationic surfactant. Finally, the method was adopted to determine Cc values of 7 quaternary ammonium surfactants differing in the polar heads nature and further three amine oxide surfactant at pH ​= ​1 where they are protonated.

Influence of Inorganic Salts and pH on Surface Activity of Biodegradable Amido Gemini Amine Oxide Surfactant.

The present study was designed to provide information regarding the influences of pH and inorganic salts on the surface activity of the amido Gemini amine oxide surfactants, the formula of which was C n H2 n +1CONH(CH2)2N+O-(CH3)-(CH2)2-(CH3)N+O-(CH2)2NHCOC n H2 n +1 (n=11, 13, 15, and 17). Their biodegradability was also investigated. The results showed that the critical micelle concentration (CMC) and the corresponding surface tension (γCMC) changed regularly with the increase of the mass concentration of NaCl and CaCl2. The optimal CMC and γCMC can be obtained by adjusting the inorganic salt content. Besides, the CMC near the isoelectric point of the surfactant is higher than the CMC within the isoelectric point. Furthermore, the biodegradability test revealed that the prepared surfactants had good biodegradability which was above 96% after 7 days.

PH-responsive micellization of an amine oxide surfactant with branched hydrophobic tail

pH-sensitive surfactants find applications in many fields, including responsive drug delivery and smart material design. The rational design of the surfactant molecular structure leads to species presenting strong variations of the micellization parameter (e.g., critical micelle concentration, cmc, and aggregate dimension) in a controlled pH range.In the present work, the micellization of the branched amine oxide surfactant N,N-dimethyl-2-propylheptan-1-amine oxide (C10DAO-branched) is studied as a function of pH in dilute aqueous mixtures. Its behavior is compared with that of the linear isomer N,N-dimethyldecan-1-amine oxide (C10DAO-linear). The samples are investigated by potentiometric titrations, fluorescence spectroscopy, and Dynamic Light Scattering (DLS). With increasing pH, micellized C10DAO-branched presents a higher tendency to remain in the protonated/cationic form with respect to the linear isomer. As a consequence, the minimum cmc value, observed when the protonated and the deprotonated/zwitterionic forms of the surfactant coexist in the micelles, is shifted to higher pH values. The volume of these C10DAO-branched “mixed micelles” is more than one order of magnitude higher than that of completely protonated or deprotonated aggregates. This is a singularity of the branched surfactant, not observed for the linear isomer. Overall, the results highlight that the branched molecular architecture of the surfactant tail, favoring the formation of low-curvature aggregates, enhances H-bonding between the protonated and deprotonated headgroups, which synergistically stabilizes the flatter surface of bulkier aggregates.Taking into account the good biodegradability of surfactants with a limited number of short side chains, purposely designed branched surfactants appear as a suitable option to accurately tune supramolecular aggregation in pH-responsive formulations.

Rosin-based chiral wormlike Micelles: Rheological behavior and its application in preparing ultrasmall gold nanoparticles

Innovations in surfactant structures are a feasible way to prepare unique molecular aggregates with interesting properties. Herein, taking dehydroabietic acid as the starting material, a new amine oxide surfactant, abbreviated as R-8-AO, was synthesized. Cryogenic transmission electron microscopy (cryo-TEM) images and circular dichroism (CD) spectra reveal that at suitable concentrations, R-8-AO molecules form rarely discovered right-handed chiral wormlike micelles, which have a cross-sectional diameter of 5–6 nm. The overlap concentration of R-8-AO is approximately 8 mM, above which the wormlike micelles began to entangle in solutions. Due to the strong van der Waals forces between R-8-AO molecules, the scaling law gives an exponent of 7.88, which is higher than the theory predicted value. Gold nanoparticles were synthesized in-situ by irradiating mixed solutions of HAuCl4 and wormlike micelles formed by R-8-AO with UV light. These ultrasmall spherical gold nanoparticles, which are located at the surface of wormlike micelles, have a uniform particle size of 3 ± 1 nm, as observed by TEM. In addition, the gold nanoparticles form a worm-like morphology induced by the wormlike micelles, showing soft-aggregate-directed nanoparticle assembly. This work is first to reveal the effectiveness of preparing ultrasmall gold nanoparticles with new morphological wormlike micelles as soft templates. The resulting organic-inorganic hybrid aggregates are also expected to find applications in catalysis and electronic fields.

Segregation of Amine Oxide Surfactants in PVA Films.

The vertical depth distributions of amine oxide surfactants, N,N-dimethyldodecyl amine N-oxide (DDAO) and N,N-dimethyltetradecyl amine N-oxide (DTAO), in poly(vinyl alcohol) (PVA) films were explored using neutron reflectometry (NR). In both binary and plasticized films, the two deuterated surfactants formed a single monolayer on the film surface with the remaining surfactant homogeneously distributed throughout the bulk of the film. Small-angle neutron scattering and mechanical testing revealed that these surfactants acted like plasticizers in the bulk, occupying the amorphous regions of PVA and reducing its glass-transition temperature. NR revealed little impact of plasticizer (glycerol) incorporation on the behavior of these surfactants in PVA. The surfactant molecular area in the segregated monolayer was smaller for DTAO than for DDAO, indicating that the larger molecule was more densely packed at the surface. Surface tension was used to assess the solution behavior of these surfactants and the effect of glycerol incorporation. Determination of molecular area of each surfactant on the solution surface revealed that the structures of the surface monolayers are remarkably consistent when water is placed by the solid PVA. Incorporation of glycerol caused a decrease of molecular area for DDAO and increase in molecular area for DTAO both in solution and in PVA. This suggests that the head group interactions, which normally limit the minimum area per adsorbed molecule, are modified by the length of the alkyl tail.

Synthesis and properties study of novel fluorinated surfactants with perfluorinated branched ether chain

In this work, novel branched fluorinated cationic, amphoteric, gemini, amine oxide and anionic surfactants were prepared using perfluoro-2-methyl-2-pentene as starting material. All the steps were easy work-up, mild reaction conditions, low cost and high yields. The effect of salt and pH on the surface activities of the newly prepared surfactants were studied. The results showed that each surfactant boasted well surface activity (they had a reduced surface tension of water as low as 19.88 mN/m) and salt resistance. These surfactants exhibited better acid and alkali resistance except that the anionic surfactant was slightly sensitive to acid. Besides, spreading property and thermal stability of the surfactants were investigated. This series of surfactants had favorable thermal stability (most of them were stable above 200 ℃) and can spread on the oil surface at critical micelle concentrations. These excellent properties indicate that these surfactants possess good prospect for industrial applications. The synthesis method of fluorinated surfactant proposed in this paper is a very successful means.

Study of the Gas Hydrate Antiagglomerant Performance of a Series of Mono- and Bis-amine Oxides: Dual Antiagglomerant and Kinetic Hydrate Inhibition Behavior

Antiagglomerants (AAs) are surfactants used in the upstream oil industry to prevent gas hydrate plugging in flow lines. Most, if not all, AAs used in the field today are cationic quaternary ammonium surfactants and function using the “hydrate-philic” mechanism. In this study, we have synthesized a series of butylated mono- and bis-amine oxide surfactants with aliphatic tails with chains of 9–17 carbon atoms and either amide or ester spacer groups. Their performance as hydrate-philic AAs has been investigated in a sapphire autoclave and sapphire rocking cells with a Structure II-forming natural gas mixture. There was generally good agreement regarding the performance and relative ranking of the surfactants between the two sets of equipment. The AA performance of the amine oxide surfactants depended on many factors, including the polar head and spacer groups, tail length, subcooling at hydrate onset, salinity, and the composition of the hydrocarbon fluid. Amido amine oxide surfactants performed better than the equivalent ester amine oxide, probably due to the stronger hydrogen-bonding ability of the amide group. The bis-amine oxide surfactants were designed with optimum interamine distance for best Structure II crystal growth inhibition and performed better as AAs than did the mono-amine oxide surfactants. The amido bis-amine oxide surfactants showed reasonable seawater biodegradation rates over 28 days, giving biological oxygen demand values of 25–40%. The bis-amine oxide surfactants in particular also showed a strong kinetic hydrate inhibition effect, which could be very useful for field applications. Thus, these surfactants could be used first as kinetic hydrate inhibitors (KHIs), and if for any reason hydrate formation does occur they could also function as AAs to prevent hydrate blockages under certain conditions.

Environmental fate of amine oxide: Using measured and predicted values to determine aquatic exposure

Amine oxide (AO) surfactants are used widely in North American household detergents resulting in >44,000mtons disposed down the drain annually. Due to AOs substantial down the drain disposal volume, wide dispersive use, and high aquatic toxicity, there is a need to evaluate ecological exposure and corresponding risk. This study refined the current knowledge regarding the fate of AO disposed down the drain through laboratory simulation studies to evaluate biodegradation in the sewer and during activated sludge wastewater treatment. A monitoring program which measured effluent AO concentrations for the dominant carbon chain lengths, C12 and C14, at 44 wastewater treatment plants (WWTP) across the continental US was also conducted. The study results were then used as input into probabilistic exposure models to predict US receiving stream concentrations. In three separate OECD 314A Sewer Water Die-Away studies AO was rapidly biodegraded with >76% mineralized by study completion and the geometric mean of the primary biodegradation rates being 0.184h−1. Two OECD 303A Activated Sludge WWTP Simulation studies showed rapid and complete biodegradation of AO with ≤0.09% of parent AO remaining in the effluent, ≤0.03% of parent AO sorbed to sludge solids, and >97% complete mineralization of AO. Monitoring at US WWPTs confirmed low levels of AO in effluents with mean C12 and C14AO concentrations of 52.8 and 20.1ng/L respectively. Based on the monitoring data, the 90th percentile concentrations of C12 and C14AO for 7Q10 low flow stream conditions were >2 orders of magnitude lower than the predicted no effect concentrations indicating negligible aquatic risk from AO in US receiving streams. This study verifies that AO is safe for the aquatic environment even at the currently high usage volumes due to rapid biodegradation during transit through the sewer and wastewater treatment.

The stability study of myristyl dimethyl amine oxide as an amphoteric surfactant in strong oxidant media containing 5 % m/m sodium hypochlorite through measurement of decomposing rate using high performance liquid chromatography and two phase titration

Myristyl dimethyl amine oxide is a surface-active agent (surfactant) that has been used in recent years widely in detergent industry as the foaming agent and a viscousing agent. Although this type of surfactants are very stable, however, in some specific chemical media such as strong acid and alkaline cleaners, oxidant media containing sodium hypochlorite may not have sufficient stability. In this study, we will study the effective variables on the decomposition of mirystyl dimethyl amine oxide surfactant with trading name of and obtain the rate constant and reaction order of decomposition reaction of the surfactant in specific chemical media for each of these variables and finally the rate law of decomposition. The results of this study show that the decomposition rate of the Ammonyx surfactant to the concentration of NaOH is first-order and the rate constants at three temperatures to 4, 20 and 47 degrees of Celsius are 1.8655×10 -4 , 2.7548×10 -4 and 4.3294×10 -4 hr -1 respectively. The Ammonyx surfactants decomposition rate relative to the NaClO concentration is first-order and the rate constant in the three mentioned temperatures is 3.4682×10 -4 , 4.9251×10 -4 and 7.2582×10 -4 hr -1 respectively. Finally, the decomposition rate of Ammonyx relative to surfactant concentration (like other two variables) is first-order and the rate constant at above temperatures equal to 1.6892×10 -4 , 3.2205×10 -4 and 5.8045×10 -4 hr -1 respectively. The activation energy for the decomposition of Ammonyx in collision with NaOH, NaClO and the surfactant molecules equals to 14.3, 12.55, 20.85 kJ mol and Arrhenius constants for these molecules equals to 0.0975 hr -1 , 0.0823 hr -1 and 0.6542 hr -1 respectively. In addition, for comparing the accuracy of the two-phase titration results, high performance liquid chromatography HPLC method has also been used. For this purpose, surfactant concentrations in some samples under study were also measured by using analytical HPLC system. The results showed that two-phase titration data have good agreement with HPLC data but chromatography has less accuracy and precision from two phase titration method.

Synthesis, characterization, and surface properties of amide amine oxides based on natural vegetable oil

ABSTRACTTwo types of novel amine oxide surfactants, castor oil amide amine oxide and cottonseed oil amide amine oxide, have been successfully synthesized via a two-step synthetic route with mild reaction conditions, the chemical structures of which were confirmed by mass spectra (MS) and FTIR spectra. Their surface activities have been measured. The results show that these synthesized amide amine oxide surfactants reduced the surface tension of water to a minimum value of approximately 32.48 mN/m at a concentration of 5.06 × 10−5 mol/L. It was also found that these novel amide amine oxide surfactants exhibited strong emulsifying power.

PH and temperature-responsive wormlike micelles formed by single amine oxide surfactant

ABSTRACTIn this paper, a novel type of pH- and temperature-responsive smart wormlike micelles based on (Z)-N,N-dimethyl-3-(octadec-9-enamido) propan-1-amine oxide (OAPAO) synthesized was studied. The structure of OAPAO was characterized by 1H NMR and FTIR. The micellization and aggregation properties of the OAPAO surfactant in aqueous solution at different pH values were studied using equilibrium surface tension. The OAPAO solution exhibited pH-regulated surface activity at the air–water interface by assessing relevant parameters such as cmc, γcmc, Гmax, and Amin at pH = 2.10, 6.80, and 11.90. The viscosity and rheological measurements demonstrated the pH-sensitive flowing behavior and property, which was attributed to the interactions transition between the OAPAO head groups. Moreover, the system could be promptly switched between low viscous fluid and highly viscoelastic fluid by alternatively adjusting the pH between 2.05 and 6.82. Combining the distribution state of OAPAO, a mechanism for the different intermolecular forces at different pH regions was proposed. Furthermore, the OAPAO solution exhibited an evident temperature-responsiveness at pH = 6.82 and 11.88 in a certain temperature range (25–65°C) resulting from the effect of temperature on the hydrophobic effect and the intermicellar branching junctions.

Synthesis and properties of cocotriethoxylpropanediamine oxide

ABSTRACTA new kind of amine oxide surfactant – cocotriethoxylpropanediamine oxide (CTPDAO) – was synthesized by a two-step process. The molecular structure was characterized by FTIR spectra and 1H NMR. The new surfactant showed high surface activity in aqueous solution in the surface tension measurement. Emulsifying capacity and wetting ability were studied in comparison to dodecyldimethylamine oxide (DDMAO). The results indicate that this new surfactant could reach the lowest surface tension of 30.4 mN m−1 in aqueous solution with a critical micelle concentration (CMC) of 0.23 mmol L−1. The wetting ability of DDMAO is better than that of CTPDAO. Compared with CTPDAO, DDMAO shows a greater capacity to emulsify soybean oil, although CTPDAO is a better emulsifying agent for liquid paraffin. The foaming properties and thickening function of DDMAO and CTPDAO mixed with alcohol ether sulfate (AES) and dodecylbenzene sulfonate (LAS) were also investigated. The results show that CTPDAO is a superior foam stabilizer than DDMAO while CTPDAO and DDMAO both have excellent thickening functions.

아민 옥사이드 양쪽성 계면활성제 첨가가 리포좀 특성에 미치는 영향에 관한 연구

In this study, zwitterionic surfactants were added to liposome systems at different pH conditions to understand the effect of surfactants on liposome characteristics. For this purpose, amine oxide surfactants having different hydrocarbon chain lengths were synthesized and the structure of the resulting product was elucidated by using H NMR, C NMR, and FT-IR. In addition, the physical properties of newly synthesized surfactants such as critical micelle concentration (CMC), surface tension and isoelectric point were measured. The stability characteristics of liposome systems including average particle sizes and zeta potentials were measured by varying pH and hydrocarbon chain lengths of an amine oxide surfactant. Effects of the pH and hydrocarbon chain length of an amine oxide surfactant on fluidity of a liposome membrane were also examined by measuring the deformability and the binding degree between the surfactant and liposome.

A “worm”-containing viscoelastic fluid based on single amine oxide surfactant with an unsaturated C22-tail

A “worm”-containing viscoelastic fluid based on single unsaturated C22-tailed amine oxide surfactant shows pH-controlled thermo-thickening behaviour.

Wetting Ability in Aqueous Mixtures of Amine Oxide with Anionic and Nonionic Surfactants

The wetting abilities of amine oxide surfactants (dodecyl dimethylamine oxide, DDMAO and dihydroxyethyl dodecylamine oxide, DDEAO), alcohol ether sulfate (AES), ethoxylated alcohols with different number of ethylene oxide units (AEOn, n = 3, 5, 7, 9) and mixtures of amine oxides with AES and AEOn were measured according to the canvas descending method. The effect of surfactant concentration, surfactant type, number of ethylene oxide unit and temperature on the wetting ability of mixed systems has been analyzed. The results show that the wetting abilities of DDEAO and DDMAO are better than those of AES, AEO9 and AEO3, and similar to those of AEO5 and AEO7. For all mixed systems, the optimum wetting ability appears at equal weight mixtures in the weight ratio range investigated. These mixtures show a synergistic effect. Higher temperatures imply higher wetting ability in aqueous mixtures of DDMAO with AES and AEO3 at weight ratio = 1 : 1.

Protonation Behavior and Solution Properties of Amine Oxide Surfactants Containing a Pyridyl Group

Hydrogen bonding between surfactant molecules plays an important role in self-assembly formation. For long alkyl chain amine oxide surfactants, the specific protonation degree dependence of some solution properties has been considered to be due to hydrogen bonding between protonated and deprotonated species. In addition to this type of hydrogen bonding, we introduced a pyridyl group into an alkylamine oxide molecule as a new hydrogen-bonding site. The pyridyl group has three different structural isomers based on the position of the substituent. An amine oxide group in pyridylamine oxides was preferentially protonated. In addition, protonation of the pyridyl group revealed a pronounced substituent position effect on the critical micelle concentration, micellar size, and solubilization of oil-soluble dye into micelles. The intermolecular or intramolecular hydrogen bond formation could be controlled by altering the substituent position.

Solution Behavior of Long–alkyl–chain Amide Amine Oxide Surfactants Having Multiple Hydrogen-bonding Sites

Abstract We investigated the surface tension behavior and gelation ability of amide amine oxide surfactants with different numbers and arrangements of amide groups, and different spacer lengths between the amide and amine oxide groups. Whether the amide groups work as the polar head groups or they are incorporated in the hydrophobic part depended on the spacer length. The number and arrangement of amide groups were important in the hydrogen-bond formation between surfactant molecules.