Preparation and properties of glycerol-based double- or triple-chain surfactants with two hydrophilic ionic groups

A novel series of glycerol-based double- or triple-chain surfactants with two sulfonate, two sulfate or two carboxylate groups was conveniently prepared by reactions of 1-O-alkylglycerol diglycidyl ethers with long-chain fatty alcohols, and followed by reactions with propanesultone, chlorosulfonic acid or bromoacetic acid, respectively. The sulfate and carboxylate types of compounds have higher water solubilities than the corresponding sulfonate type of compound bearing the same lipophilic group. The triple-chain surfactants show excellent surface-active properties, such as micelle forming and ability to lower surface tension, compared not only with the corresponding single-chain anionic surfactants, but also with the corresponding double-chain surfactants. The effect of the difference in head groups of these compounds on surface-active properties is described. Foaming properties, wetting ability and lime-soap dispersing requirement are also discussed.     

Synthesis and properties of novel alkyl sulfate gemini surfactants

Four anionic gemini surfactants of the sulfate type C₁₂C_nC₁₂, where n is the spacer chain length (n = 3, 4, 6, and 10) were synthesized. The structures of these surfactants were confirmed by FT‐IR, ¹H NMR, ESI mass spectra (ESI‐MS), and elemental analysis. The surface‐active properties of these compounds were investigated by means of surface tension, electrical conductivity, and fluorescence measurements. Premicellar aggregations were found for the four gemini surfactants, as revealed by the conductivity measurement. The formation of premicellar aggregates may account for the discrepancy between the critical micelle concentration (cmc) obtained by the surface tension and conductivity measurement. The cmc values of these gemini surfactants were much lower than that of sodium dodecylsulfate (SDS) and decreased monotonously with the increase of spacer chain length from 3 to 10. The effect of spacer chain length on the performance properties like foaming, emulsion stability, and lime soap dispersing ability were also studied and discussed. Practical applications : Alkyl sulfate surfactants are one of the most widely used surfactants. The new alkyl sulfate gemini surfactants synthesized in our study are more surface‐active than sodium dodecylsulfate. These gemini surfactants possess low critical micelle concentrations, high emulsion stability, and excellent lime soap dispersing ability. They have potential applications in the fields of cosmetics, detergents, etc.     

Preparation,Characterization and Properties of Novel Cationic Gemini Surfactants with Rigid Amido Spacer Groups

A series of novel cationic gemini surfactants with rigid amido groups inserted as the spacers, named C ₁₂ ‐PPDA‐C ₁₂ , C ₁₄ ‐PPDA‐C ₁₄ and C ₁₆ ‐PPDA‐C ₁₆ , were synthesized by a two‐step reaction with dimethyl terephthalate, N,N‐dimethyl propylene diamine and alkyl bromide as raw materials. The chemical structures of the prepared compounds were confirmed by IR, ¹H and ¹³C NMR and element analysis. Surface activity properties of the synthesized compounds were investigated by surface tension, electrical conductivity and fluorescence. Increasing the number of carbon atoms in the hydrophobic alkyl chain, decreased the critical micelle concentration (CMC), surface tension at the CMC and the minimum surface area. Other relevant properties including foaming ability and emulsion stability were investigated. The results indicated that the synthesized gemini surfactants possess good surface properties, emulsifying properties and steady foam properties.     

Preparation and properties of new lactose-based surfactants

A new group of nonionic saccharide-based surfactants, N-alkanoyl-N-methyllactitolamines (alkanoyl: decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl), were synthesized and characterized. Surface properties such as critical micelle concentration, standard free energy of adsorption, standard free energy of micellization, surface tension reduction efficiency, effectiveness of surface tension reduction, surface excess concentration, and surface area demand per molecule as well as foaming properties (i.e., foam volume and foam stability), contact angle, antiraicrobial activity, and biodegradability were determined. The selected performance properties were evaluated in relation to commercially available alkyl polyglucosides (Glukopon 600 EC(HH)-a Henkel product), and oligooxyethylenated decyl (C₁₀E₄) and dodecyl (E₁₂E₅) alcohols. The foaming-stabilizing effect and contact angle suggest that the lactose-derived surfactants that were studied share some common properties with alkyl polyglucosides that are different from those with an oligooxyethylene grouping. All tested N-alkanoyl-N-methyllactitolamines were practically nontoxic to bacteria and yeasts. These compounds are readily biodegradable in the Closed Bottle test inoculated with activated sludge. N-Alkanoyl-N-methyllactitolamines with lower chain lengths (C₁₀–C₁₄) biodegraded at a slightly faster rate. Biological properties showed that this class of compounds fulfills all requirements needed for environmental acceptance.     

Synthesis and Surface Active Properties of tri[(N‐alkyl‐N‐ethyl‐N‐Sodium carboxymethyl)‐2‐Ammonium bromide ethylene] Amines

Trimeric betaine surfactants tri[(N‐alkyl‐N‐ethyl‐N‐sodium carboxymethyl)‐2‐ammonium bromide ethylene] amines were prepared with raw materials containing tris(2‐aminoethyl) amine, alkyloyl chloride, lithium aluminium hydride, sodium chloroacetate, and bromoethane by alkylation, Hoffman degradation reaction, carboxymethylation and quaternary amination reaction. The chemical structures of the prepared compounds were confirmed by FTIR, ¹H NMR, MS and elemental analysis. With the increasing length of the carbon chain, the values of their critical micelle concentration initially decreased. Surface active properties of these compounds were superior to general carboxylate surfactants C₁₀H₂₁CHN⁺(CH₃)₂COONa. The minimum cross‐sectional area per surfactant molecule (A_min), standard Gibbs free energy adsorption (ΔG_ads) and standard Gibbs free energy micellization (ΔG_mic) are notably influenced by the chain length n, and the trimeric betaine surfactants have greater ability to adsorb at the air/water interface than form micelles in solution. The efficiency of adsorption at the water/air interface (pC₂₀) of these surfactants increased with the increasing length of the alkyl chain. Their foaming properties, wetting ability of a felt chip, and lime‐soap dispersing ability were also investigated.     

Effects of Molecular Structure and Temperature on Micellization of Cationic Ammonium Gemini Surfactants in Aqueous Solution

Micellization of four cationic quaternary ammonium gemini surfactants, having a diethyl ether or hexyl spacer with the alkyl chain lengths of 12 and 16 carbon atoms, was studied using isothermal titration microcalorimetry (ITC) and electrical conductivity measurements in the temperature range from 298.15 to 313.15 K. In this temperature range, where surfactants are normally applied, the temperature almost does not influence the critical micelle concentration (CMC) and the degree of micelle ionization (α) values of the gemini surfactants, and the replacement of a hexyl spacer by a diethyl ether spacer leads to a slight decrease in the CMC and α values. However, as the alkyl chain length increases from 12 to 16 carbon atoms, the CMC values significantly decrease from 0.99–1.19 mM to 0.020–0.057 mM. In particular, the enthalpy of micellization (ΔH_mic ) and the associated thermodynamic parameters show obvious changes with varying temperature and molecular structure. ΔH_mic becomes much more exothermic at higher temperature or for the surfactants with a more hydrophilic spacer. Moreover, the heat capacity change of micellization (ΔC _{P, mic} ) is less exothermic for the surfactants with a more hydrophilic spacer or a longer alkyl chain. The enthalpy–entropy compensation data show that the surfactants with longer alkyl chains have a more stable micellar structure.     

Preparation,surface-active properties and acid decomposition profiles of a new “soap” bearing a 1,3-dioxolane ring

New soap-type surfactants bearing a 1,3-dioxolane ring were prepared in good yields by the acid-catalyzed condensation of 1-O-alkylglycerols (alkyl: decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, orcis-9-octadecenyl) with oxocarboxylic acid esters, followed by alkaline hydrolysis without any expensive reagent and special equipment. These surfactants were soluble in alkaline water at room temperature. Their critical micelle concentrations were much smaller than that of sodium dodecanoate. An alkaline solution of the octadecyl homologue was nonfoaming, but the other homologues, including thecis-9-octadecenyl derivative, showed high foaming ability in alkaline solutions. The structural effect of these compounds on the area per molecule at the surface is also discussed. Because these surfactants contain a 1,3-dioxolane ring, they can be utilized as a new acid-decomposable type of cleavable surfactant. At pH 1, they decompose almost completely into nonsurface-active species after 80 min.     

Synthesis, characterization and surface properties of 1-N-l-tryptophan-glycerol-ether surfactants

A novel homologous series of 1-N-l-tryptophanglycerol-ether surfactants was synthesized and characterized. The precursor compounds, 3-alkyloxy-1-chloropropan-2-ols, were prepared from epichlorohydrin and aliphatic alcohols with alkyl chain lengths of 9–16 carbon atoms. Tryptophan was then attached to the monosubstituted glycerol backbone from its α-amino group through an α-NH-C bond. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentrations of the new surfactants, as well as the negative logs of the surfactant concentrations required to reduce the surface tension of the solvent by 20 mN/m (pC ₂₀) and the interfacial areas occupied by the surfactant molecules, were calculated from aqueous surface tension measurements using the Wilhelmy plate technique.     

Synthesis and Surface Active Properties of 1,1,1,1-Tetra-(2-oxypropyl Sulfonate-3-alkylether-propoxy)neopentanes

Tetrameric sulfonate surfactants 1,1,1,1-tetra-(2-oxypropyl sulfonate-3-alkylether-propoxy)neopentanes were prepared with raw materials containing epichlorohydrin, pentaerythritol, long-chain alcohols, 1,3-propane sultone and sodium hydroxide by esterification, a ring opening reaction, and a sulfonation reaction. The chemical structures of the prepared compounds were confirmed by FTIR, ¹H-NMR and element analysis. With the increasing length of the carbon chain, the values of their CMC initially decreased. The longer the alkyl chain, the higher the melting point. The Krafft point of all these tetrameric sulfonate surfactants was below 0 °C and they had excellent water solubility. These compounds were superior in surface active properties to general sulfonate surfactants SDS. The efficiency of adsorption at the water/air interface (pC₂₀) of these surfactants was very high. Their foaming properties, their wetting ability of a felt chip, and their lime-soap dispersing ability was investigated.     

Synthesis and Properties of Alkoxyethyl β‐d‐Xylopyranoside

In order to improve the water solubility of sugar‐based surfactants, alkyl β‐d‐ xylopyranosides, novel sugar‐based surfactants, 1,2‐trans alkoxyethyl β‐d‐ xylopyranosides, with alkyl chain length n = 6–12 were stereoselectively prepared by the trichloroacetimidate method. Their properties including hydrophilic–lipophilic balance (HLB) number, water solubility, surface tension, emulsification, foamability, thermotropic liquid crystal, and hygroscopicity were investigated. The results indicated that their HLB number decreased with increase of alkyl chain, the water solubility improved since the hydrophilic oxyethene (─OCH₂CH₂─) fragment was introduced. The dissolution process was entropy driven at 25–45 °C for alkyl chain length n = 6–10. Octyloxyethyl β‐d‐ xylopyranoside had the best foaming ability. Nonyloxyethyl β‐d‐ xylopyranoside had the best foam stability and the emulsifying ability was better in toluene/water system than in rapeseed oil/water system. The surface tension of in aqueous solution dropped to 27.8 mN m^?1 at the critical micelle concentration, and it also showed the most distinct thermotropic liquid phases with cross pattern texture upon heating and the fan schlieren texture on cooling. Hexyloxyethyl β‐d‐ xylopyranoside possessed the strongest hygroscopicity. Based on the effective improvement of water solubility, the prepared alkoxyethyl β‐d‐ xylopyranosides showed excellent surface activity and are expected to develop their practical application as a class of novel sugar‐based surfactants.     

Multivariate quantitative structure-activity relationships for the aquatic toxicity of technical nonionic surfactants

The aquatic toxicity of 36 technical nonionic surfactants (ethoxylated fatty alcohols) was examined toward two freshwater animal species, the fairy shrimp Thamnocephalus playtyurus and the rotifer Brachionus calyciflorus. Responses of the two species to the surfactants were generally similar. A multivariate-quantitative structure-activity relationship (M-QSAR) model was developed from the data. The M-QSAR model consisted of a partial least squares model with three components and explained 92.4% of the response variance and had a predictive capability of 89.1%. The most important physicochemical variables for the M-QSAR model were the number of carbon atoms in the longest chain of the surfactant hydrophobe (redC), the molecular hydrophobicity (log P), the number of carbon atoms in the hydrophobe (C), the hydrophilic-lipophilic balance according to Davis (Davis), the critical packing parameter with respect to whether the hydrophobe was branched or not (redCPP), and the critical micelle concentration. Surfactant toxicity tended to increase with increasing alkyl chain lengths.     

Preparation and properties of sulfonate salt-type cleavable surfactants with a 1,3-dioxane ring

A series of di-anionic cleavable surfactants were prepared by the condensation of aldehydes with 2,2-bis(hydroxymethyl)-1,3-propanediol, followed by reaction with 1,3-propanesultone in the presence of sodium hydride. Surfactant 5a had a different¹H nuclear magnetic resonance spectrum in D₂O than products 5b−d. This was rationalized by its different conformation, which originates from the self-coiling of its alkyl chain. The critical micelle concentrations, Krafft points and hydrolysis properties of these surfactants were determined.     

Preparation and surface active properties of amphipathic compounds with two sulfate groups and two lipophilic alkyl chains

These compounds with various connecting groups between the two lipophilic groups were prepared by the reaction of glycol diglycidyl ethers with long-chain alcohols, followed by sulfation with chlorosulfonic acid or with a mixture of chlorosulfonic acid and acetic acid. The Krafft point of all these new amphipathic compounds was below 0°C, and they had good water solubility. These compounds were superior in surface active properties to general anionic surfactants with one lipophilic chain and one hydrophilic group, such as sodium dodecylsulfate. The effect of the structure of the connecting group on CMC, γ_CMC, foaming properties and wetting ability was investigated. They also showed excellent lime-soap dispersing ability.     

Syntheses and Characterization of Some Cationic Surfactants

A series of novel cationic surfactants were synthesized from the quaternization of triethyl amine and various long chain alkyl halide. The chemical structure of the prepared compounds was confirmed using elemental analysis, FTIR and ¹H-NMR spectra. The physical properties of the synthesized surfactants including, electrical conductivity, critical micelle concentration, (CMC) and the degree of ionization of the micelle, (β) were studied. The thermodynamic parameters of micelle formation, standard free energy ΔG _m°, enthalpy ΔH _m°, and entropy ΔS _m° were calculated. The results of the surface parameter determination were correlated with their chemical structures. It was found that the hydrocarbon chain length is the main factor which has an effect on the value of the thermodynamic parameters.

Alkyl Xylosides: Physico‐Chemical Properties and Influence on Environmental Bacteria Cells

A group of four selected non‐ionic surfactants based on carbohydrates, namely octyl d ‐xyloside (C₈X), nonyl d ‐xyloside (C₉X), decyl d ‐xyloside (C₁₀X) and dodecyl d ‐xyloside (C₁₂X), have been investigated to accomplish a better understanding of their physico‐chemical properties as well as biological activities. The surface‐active properties, such as critical micelle concentration (CMC), emulsion and foam stability, the impact of the compounds on cell surface hydrophobicity and cell membrane permeability together with their toxicity on the selected bacterial strains have been determined as well. The studied group of surfactants showed high surface‐active properties allowing a decrease in the surface tension to values below 25 mN m^?1 for dodecyl d ‐xyloside at the CMC. The investigated compounds did not have any toxic influence on two Pseudomonas bacterial strains at concentrations below 25 mg L^?1. The studied long‐chain alkyl xylosides influenced both the cell inner membrane permeability and the cell surface hydrophobicity. Furthermore, the alkyl chain length, as well as the surfactant concentration, had a significant impact on the modifications of the cell surface properties. The tested non‐ionic surfactants exhibited strong surface‐active properties accompanied by the significant influence on growth and properties of Pseudomonas bacteria cells.     

Effect of position of ester group and temperature on critical micelle concentration of ester containing surfactants

The critical micelle concentrations of sodium sulfoalkyl alkanoates, C_nH_2n+1 COO(CH₂)_mSO₃Na (n=9, 10, and 11; m=2, 3, and 4), in aqueous solution were measured by an electro conductivity method from 15 to 50 C. Plots of critical micelle concentrations versus temperature show a minimum for all of the surfactants. Increasing the number of methylene groups between the ester and sulfonate groups in the surfactant molecule lowered the temperature at which the minimum critical micelle concentration was observed. When the percentage deviation of critical micelle concentration values obtained at different temperatures from critical micelle concentration values at 30 C was plotted as a function of the temperature, deviation in the range below 30 C increased with length of the hydrocarbon chain in the fatty acid portion of the surfactant, and decreased with the increase in length of the hydrocarbon chain situated between ester and sulfonate groups. These phenomena suggest that the change of interaction between the ester group and water molecule with the temperature is largely dependent on the position of the ester group in the alkyl chain of the surfactant. On the other hand, deviation values above 30 C increased with length of the hydrocarbon chain in the fatty acid portion and of the hydrocarbon chain situated between ester and sulfonate groups. These results indicate that interaction between the ester group and water molecule decreases with rise in temperature. The enthalpies, free energies, and entropies of micelle formation were calculated from temperature variation of critical micelle concentrations, and are consistent with current theories of the role of solvent in micelle formation.     

Retracted: Synthesis,Characterization, and Surface Activities of Polymeric Cationic Thiol Surfactants in Aqueous Medium

A series of cationic polyurethane surfactants [PQ_8-18] were synthesized by the reaction of alkyl bromoacetate (namely: octyl-, decyl-, dodecyl-, tetradecyl-, hexadecyl-, and octadecyl bromoacetate) as quaternizing agents and modified polyurethane contains tertiary amine species. Modified polyurethane was prepared by the reaction of toluene diisocyanate (TDI) and triethanol amine monomercaptoacetate. The chemical structures of the prepared surfactants were confirmed using elemental analysis, Fourier transform infrared spectroscopy (FTIR), and Proton nuclear magnetic resonance (¹H NMR) spectroscopy. The molecular weight measurements of the prepared polymers showed that the segments of each polymer contain average 10 units of the urethane-triethanol amine mercaptoacetate. The surface activities of the prepared surfactants including: surface tension (γ), effectiveness ( π_cmc), concentration at micelle formation (CMC), efficiency (Pc₂₀), maximum concentration at the interface (Γ_max), and the average area occupied by each surfactant molecule at the interface at equilibrium ( A _min) of surfactants solutions were established at 25°C. The surface tension and the critical micelle concentration values of the prepared surfactants were gradually decreased by the gradual increase of their alkyl chain length. The prepared cationic surfactants showed efficient activity as inhibitors for dissolution of carbon steel in an acidic medium and also as a biocide against the growth of bacteria, fungi, and yeast.     

Synthesis,characterization, and surface properties of phenylalanine-glycerol ether surfactants

A novel homologous series of 1-N-l-phenylalanine-glycerol ether surfactants was synthesized in satisfactory yields via reaction of epichlorohydrin with aliphatic alcohols with alkyl chains of 10–15 carbon atoms. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentration (CMC), surface tension at the CMC (γ_CMC), surfactant concentration required to reduce the surface tension of the solvent by 20 mN/m (pC₂₀), and the interfacial area occupied by the surfactant molecules (A_min) were determined from aqueous surface tension measurements using the Wilhelmy plate technique.     

Polymeric surfactants for enhanced oil recovery. Part II—the hlb-cmc relationship of ethoxylated alkylphenol-formaldehyde polymeric surfactants

The natural log of critical micelle concentration (CMC) values obtained from the natural log discontinuities in surface tension-concentration relationships, through the least-squares regression analysis, were plotted against the respective hydrophile-lipophile balance (HLB) values of four groups of ethoxylated octylphenol-, dodecylphenol-, tetradecylphenol- and hexadecylphenol-formal-dehyde polymeric surfactants. The obtained HLB-CMC relationship for the investigated compounds can be represented satisfactorily by the linearized equation In (CMC) = a—b (HLB). Values of the two constants a (intercept) and b (slope) for 16 of these compounds were determined at 28, 38, 48 and 58°C, using the least-squares regression analysis of data. The study revealed that both a and b values increase with increasing number of carbon atoms in the ethoxylates of polymeric compounds having a linear alkyl chain. The influence of branching is reflected in the values of a and b of the compounds having a branched dodecyl chain. The most striking feature of the obtained equation is that the CMC decreases with increasing HLB (negative slope). This observation is contrary to what is generally expected for both ionic and nonionic surfactants.     

Aggregation and Thermodynamic Properties of Some Cationic Gemini Surfactants

In this study, the gemini surfactants of the alkanediyl-α-ω-bis(alkyl dimethyl ammonium) dibromide type, on the one hand, with different alkyl groups containing m carbon atoms and an ethanediyl spacer, referred to as “m-2-m” (m = 10, 12 and 16) and, on the other hand, with n-C₁₆ alkyl groups and different spacers containing s carbon atoms, referred to as “16-s-16” (s = 2, 6, 10 and Ar (8)) have been synthesized, purified and characterized. The critical micelle concentration (CMC), micelle ionization degree (α) and Gibbs free energy of micellization (∆G _mic) of these surfactants and the monomeric cationic surfactants DTAB and CTAB have been determined by means of electric conductivity measurements. In addition, the temperature dependence of the CMC was determined for the 10-2-10 gemini surfactant. The CMCs of the gemini surfactants are found to be much lower than those of the corresponding monomeric surfactants and the effect of the hydrophobic alkyl chain length is more important than that of the spacer. The CMC of 16-s-16 passes through a maximum of (or around) s = 6 and then decreases for s = 10. The presence of a maximum CMC is explained by the contribution of a change of conformation of the surfactant with increasing spacer chain length. The changes of α with s and m are found qualitatively similar to those found for CMC values. The values of ∆G _mic are more negative for the dimers than for the monomers and also change with an increasing spacer carbon number, as CMC values do. The thermodynamic parameters of micellization indicate that the micellization of 10-2-10 is enthalpy driven.