Surfactants containing ethylene oxide: Relationship of structure to biodegradability

Anionic ethoxy sulfate and nonionic ethoxylate surfactants were prepared from the following straight-chain hydrophobes: fatty or Ziegler primary alcohols, oxo alcohols derived from straight-chain olefins, secondary straight-chain alcohols and straight-chain alkylphenols. These were studied to relate biodegrability to the following elements of structure: the nature of the connecting link, its position of attachment to the hydrophobe, the chain length of the hydrophobe, and the length of the ethylene oxide chain used. Previously described methods were used to estimate both rate and completeness of degradation in river water as well as activated sludge environments. Data are presented to support the following conclusions.

1. 1)
   All surfactants derived from straight-chain primary and secondary alcohols are rapidly and completely degraded with loss of surfactant properties. The length of the ethylene oxide chain from zero up to ten units has no effect on the rate or the completeness of degradation. In such surfactants, the ethylene oxide chain is completely degraded.     
   
   

Viscosity characteristics of aqueous solutions of block copolymers of propylene and ethylene oxides

Brookfield viscosity measurements were made on aqueous solutions of surface-active agents composed of block copolymers of propylene and ethylene oxides in which the molecular weights of the polymers varied from 1100 to over 15,000. The hydrophobia bases were polyoxypropylene glycols varying in molecular weight from 940 to 4000. To these were added varying amounts of ethylene oxide so that the polyoxyethylene hydrophil comprised from 15 to 80% of the surfactant total weight. This work has materially expanded previous viscosity studies of aqueous solutions of nonionic surfactants by using a unique type of hydrophobe, two ethylene oxide chains, and far higher molecular weights of hydrophobe and of hydrophil, up to 280 moles of ethylene oxide. The surface-active agents with hydrophobe base molecular weights from 940 to 1100, and in which the polyoxyethylene sections comprised from 15 to 80% of the total weight, did not form gels in aqueous solution. Some surfactants with a hydrophobe base molecular weight of 1750 to 2750, to which varying amounts of polyoxyethylene were added, formed gels in water at a surfactant concentration range of 40% to 80%. With a hydrophobe molecular weight of 3250, gels formed at from 30% to 90% surfactant concentration, while with one nonionic derived from a 4000 molecular weight hydrophobe, a gel formed at only 20% polyol concentration. Two viscosity maxima were found in some cases, as reported occasionally for other systems. An increase in temperature from 0C to 50C generally reduced the viscosity of systems based on hydrophobes of 1175 and lower molecular weights, and increased it in systems based on hydrophobes of 1750 and higher molecular weights. The behavior of these surfactants in forminggels is explained on the basis of hydrogen bonding, micellar aggregation and water entrapment. The moles of water per ethylene oxide group in the adduct varied with the hydrophobe base weight and with the polyoxyethylene hydrophil, and within systems showing maximum viscosities, ranged from 0.3 to 17.1, at 25C, which is much higher than observed in other nonionics.     

温度及无机盐对LMEE和SDS混合溶液表面张力的影响

通过表面张力的测定,研究了温度和不同无机盐对月桂酸甲酯乙氧基化物(laurylmethylesterethoxylate,简称LMEE)与十二烷基硫酸钠(SDS)复配物表面张力及临界胶束浓度(CMC)的影响。研究表明:混合体系的CMC在很宽的复配比例内出现最低值,25℃、未加无机盐时可使CMC最低降至3 8×10-5mol/L;温度对复配体系表面张力的影响较小,温度上升复配物的CMC略有降低。3种价态无机盐的加入均可使复配物的CMC有所降低,但与单一表面活性剂相比,温度和无机盐对复配物的CMC影响均不大,说明复配体系的抗温变及抗盐能力均有增强。     

一种新型气相色谱固定液的制备及应用

以柠檬酸、OP-10和二乙醇胺为原料合成了柠檬酸壬基酚聚氧乙烯醚单酯二乙醇酰胺。用红外光谱法表征了结构,热分析技术考察了热稳定性。以此产物作为气相色谱固定液,对一些混和组分进行分离,效果良好。     

Interaction of fluorocarbon and hydrocarbon hydrophobically co-modified PAA with a nonionic surfactant: rheological properties of polymer solutions in the absence of salt

The interaction of a new hydrocarbon (HC) and fluorocarbon (FC) co-modified poly(acrylic acid), SA-1-FX14-1, with a HC nonionic surfactant, Np7.5, was investigated by rheological measurements. Its solution property was compared with HC or FC modified counterpart. It was found that the incompatibility between HC and FC groups in the micellization process was improved in the solution of SA-1-FX14-1. The terpolymer SA-1-FX14-1 associated with Np7.5 more like SA-2 rather than FX14-2. The latter interacted weakly with the HC surfactant due to the lipophobic tendency of the FC hydrophobe. The random distribution of FC and HC hydrophobes along the polyelectrolyte backbone was confirmed to be responsible for the compromised miscibility of HC and FC hydrophobes demonstrated in the system of SA-1-FX14-1 and Np7.5. Several affecting factors, such as backbone rigidity, polymer concentration, surfactant concentration, and FC modifying degree of the terpolymers, were also taken into account. In terms of hybrid surfactants, this type of hybrid polysoap is promising to serve as novel media improving the miscibility of HC and FC groups just as those hybrid small molecule surfactants have done.     

月桂酸甲酯乙氧基化物中的聚乙二醇和月桂酸甲酯的同时测定

使用C8键合硅胶色谱柱、示差折光检测器的反相液相色谱法同时测定了月桂酸甲酯乙氧基化物中的聚乙二醇和月桂酸甲酯的含量,通过优化流动相配比实现了月桂酸甲酯乙氧基化物同聚乙二醇和月桂酸甲酯的完全分离,方法简便快速,适用于产品的质量控制和工艺研究。     

Synthesis and surface activity of nonionic surfactants containing fluorocarbon hydrophobes

Nonionic surfactants having polydisperse polyoxyethylene chains and highly fluorinated hydrophobes were synthesized via a complex reaction route and their adsorption at water/air interfaces studied. They exhibit high surface activity and decrease both effectively and efficiently the surface tension of their aqueous solutions. The effect of the length of the polyoxyethylene chain upon surfactant surface activity is relatively low. Lower values of surface tension, below 30 mN m^?1, are obtained for surfactants having a low degree of ethoxylation. Surfactants having two terminal highly fluorinated hydrophobes are less surface active than analogues with one terminal hydrophobe.     

The Determination of the Effective HLB of Nonionic Surfactants by a Phenol Titration II: The Effect of Several Hydroxy Compounds

The nonionic surfactants polyoxyethylene nonyl phenol ethers have been used as models for the investigation of the change of the effective HLB of surfactants under influence of several hydroxy compounds using the phenol index method. These water-soluble additives include alcohols, glycols and glycol ethers. The change of the effective HLB of nonionic surfactant depends on the amounts and hydrophobicity of studied additives. In order to explain the change of the effective HLB of surfactants, the considerations based on the effects of the same additives on the micelle formation are also presented. These results are in remarkable agreement with the effects of the same substances on the effective HLB using other methods.     

Effect of hydrophobe structure on performance of alcohol ethoxylates

Alcohol ethoxylates are versatile surfactants because both the hydrophobic and the hydrophilic moieties can be varied readily to change performance. Many studies have focused on the effect of changes in the average length of the hydrophobe and the nature of the hydrophile. Less frequently studied, however, has been the effect on performance of hydrophobe structure, yet this can be varied easily by changing the alcohol feedstock used to make the alcohol ethoxylate. This study compares the performance of alcohol ethoxylates derived from oleochemical alcohol and oxo-alcohols derived from kerosene, butylene, or coal by the Fischer-Tropsch process. Two aspects of hydrophobe structure were found to be important for performance of alcohol ethoxylates: the overall linearity of the parent alcohol and the degree of substitution at the C2 carbon. As the linearity of the parent alcohol increases, the critical micelle concentration (CMC) decreases and the surface tension at the CMC increases. Increasing substitution at the C2 carbon increases the amount of unethoxylated alcohol in the ethoxylate but decreases the inverse cloud point temperature, wetting time, and foam stability in the absence of soil.     

Optimization of nonionic surfactants for hard-surface cleaning

The hard-surface cleaning performance of various nonionic homologs was evaluated as a function of carbon chain length, ethylene oxide (EO) content, blending and concentration. Results show carbon chain length to be very important to hard-surface cleaning. Performance significantly increases as carbon-chain length decreases, probably as a result of an increase in solvency properties as carbon chain length is decreased. EO content is also important, particularly if nonionics with longer carbon chain lengths are used. Surfactant concentration (dilution) has little effect on the optimum ethylene oxide content but significantly affects the optimum carbon chain length of the hydrophobe. With 5% homolog solutions, the optimally performing nonionic contains a C6 hydrophobe, but with 0.2% solutions, the optimal carbon chain length is shifted to the C8–C10 range. This is thought to result from a trade-off between the surfactant and solvent properties of the nonionic. Overall results show the optimal nonionic for hard-surface cleaning to consist of a blend of C6, C8 and C10 alcohols ethoxylated to a 50% EO level. Commonly used surfactant systems, e.g., alkylphenol ethoxylates and alkylphenol ethoxylate (APE)-butyl cellosolve (BC) blends, were also examined. Results show that alkylphenol ethoxylates give relatively poor performance compared with lower molecular weight linear nonionics because of the large size of their hydrophobe. Under concentrated use, a synergism does exist between APE and BC, but under dilute conditions, the addition of BC is ineffective. BC does not help the performance of low molecular weight nonionics. Surfactant-soil diffusion studies indicate that surfactant penetration of the soil may be the primary mechanism involved in the hard-surface cleaning of solid soils. Presented May 10, 1983, at the 74th Annual Meeting of the AOCS, Chicago, IL.     

Performance and properties of nonionic surfactants from linear secondary alcohols

Surfactants based on the linear secondary alcohols provide a new source of biodegradable detergents. The nonionic surfactants of these alcohols are discussed in relationship to their surfactant properties and performance in detergent formulations. The performance properties in detergent formulations are defined by the results of detergency and foam stability tests. The surfactant properties presented are viscosity, surface tension, wetting and alkaline color stability. The above properties of the nonionic surfactants from the linear secondary alcohols have been compared to the properties of the less degradable nonylphenol nonionics and to the nonionic surfactants from the linear alkylphenol, oxo alcohol and Ziegler alcohol hydrophobes.     

Laundry Detergency of Solid Nonparticulate Soil or Waxy Solids: Part II. Effect of the Surfactant Type

In this work, methyl palmitate with a melting point around 30°C was used as a model of waxy soil. Its detergency was evaluated with a hydrophilic surface (cotton) or a hydrophobic surface (polyester) using different surfactants: alcohol ethoxylate (EO9), sodium dodecyl sulfate (SDS), methyl ester sulfonate (MES), methyl ester ethoxylate (MEE), and two extended surfactants (C_12,14-10PO-2EO-SO₄Na and C_12,14-16PO-2EO-SO₄Na). The detergency efficiency at a 0.2 wt.% surfactant and 5 wt.% NaCl gradually increased while redeposition gradually decreased with increasing washing temperature in most studied surfactant solutions; this was observed both above and below the melting point of methyl palmitate on both studied fabrics. If the methyl palmitate was heated above the melting point when deposited on the fabric, it was better able to penetrate into the fabric matrix as compared to deposition below the melting point, resulting in poorer detergency for heated deposition, particularly for washing temperatures lower than the melting point. Among the surfactants studied, the nonionic surfactant (EO9) showed the highest detergency efficiency (73–94%) at any washing temperature especially on the polyester fabric. For washing temperatures below the melting point, detergency performance correlated well with the contact angle of surfactant solution on the solid methyl palmitate surface for all studied surfactants when salinity was varied. In this work, conditions resulting in the highest detergency below the melting point corresponded to the highest detergency above the melting point, suggesting this as a systematic approach to formulating below the melting point of the soil. Charge of particles or fabric was not observed to be important to the detergency mechanism, but steric factors resulting from surfactant adsorption were observed to be important mechanistic factors in waxy solid detergency.     

“Acid” pyrolysis-capillary chromatographic analysis of anionic and nonionic surfactants

A tandem “acid” pyrolysis-capillary chromatographic method for analyzing surfactants has been developed, and its application to the more common anionic and nonionic surfactant types investigated. In this method a surfactant is mixed with an acid, such as P₂O₅ or H₃PO₄, and dropped into a pyrolyzer attached to a capillary gas chromatograph. The resulting volatile pyrolyzate is carried into the chromatograph for analysis. According to the chromatograms, the point of cleavage during “acid” pyrolysis is quite selective, usually at a C-S or C-O bond. For example, LAS and ABS give peaks corresponding to the alkylbenzene precursors; primary linear alkyl sulfates and sulfonates, peaks corresponding to olefins with the same number of carbon atoms as the alkyl group; and alcohol and alkylphenol ethoxylates and ethoxylate sulfates, peaks corresponding to olefins from the alkyl group and to acetaldehyde and a higher aldehyde from the polyethoxy group. Alkylphenol derivatives are probably cleaved to form an alkylphenoxy intermediate, which then dealkylates to give the olefins. This method is quantitative for carbon number or carbon number and isomer distribution of hydrophobes in linear surfactants, semiquantitative for ethoxy content and for hydrophobes in branched chain surfactants, and qualitative for hydrotropes and certain foam additives. Surfactants, as well as mixtures of certain surfactant types, in built detergent formulations can be analyzed without isolation. Winner, Bond Award Medal, Philadelphia, October 1966.     

Selecting the optimal linear alcohol ethoxylate for enhanced oily soil removal

Use of nonionic surfactants in detergent products has become increasingly popular because of their tolerance to hardness ions and their effect on lowering the critical micelle concentration of anionics. Their performance as detergents, however, is very sensitive to changes in temperature and electrolyte concentration, which need to be carefully controlled in order to ensure that phase inversion conditions prevail. For a fixed temperature in an application, the only variables available for optimizing the performance of a system containing nonionics are: the type of nonionic, and the concentrations of electrolytes and anionics. Based on the mutual interactions of these ingredients in mixed systems, we have devised some guidelines for selection of the optimal ethylene oxide (FO) chain length in lauryl alcohol ethoxylate type of nonionics for a range of electrolytes and anionic surfactant concentrations. For any given concentration of electrolytes (sodium carbonate and sodium tripolyphosphate), anionic (sodium linear alkyl benzene sulfonate) and nonionic, the detergency of synthetic sebum from blended polyester/cotton fabrics shows a maximum as a function of average FO moles in the nonionic. Oil/water interfacial tension shows an expected reverse trend. The optimal EO moles (for maximal detergency) show a monotonically increasing trend when plotted as a function of the ratio of nonionic to anionic concentration for a fixed level of electrolyte. The optimal EO moles also increase with increasing level of electrolytes in the system. However, the effect of nonionic/anionic ratio is much stronger than the effect of electrolytes on the optimal EO moles.     

Quantitative assessment of alkyl chain branching in alcohol-based surfactants by nuclear magnetic resonance

Surfactants with branched hydrophobes have gained considerable interest, since these can be used in formulations for laundry cleaning at a wide range of conditions. The claims range from improved dissolution rate to hardness tolerance and stain removing efficacy. In contrast to the historically known heavily branched surfactants, novel branched surfactants are less compromised by increased biodegradability. These properties find their basis in the structural characteristics of the hydrophobe, such as number, position, and type of alkyl chain branches. Our current understanding of structure-property relations, however, is hampered by the lack of generic methodology needed to obtain structural data on hydrophobe branching. A nuclear magnetic resonance (NMR) approach was developed by which we could obtain a comprehensive set of quantitative hydrophobe branching parameters in alcoholbased surfactants. The ¹³C and ¹H NMR spin systems of hydrophobe branched species were assigned by means of twodimensional NMR techniques. These assignments allowed the quantitative assessment of these branched species by straight-forward signal integration in the ¹H and ¹³C NMR spectra. The quantified NMR data can be used to understand product performance and the biodegradation of surfactants with branched hydrophobes.     

Effect of alkyl groups in anionic surfactants on solution properties of anionic-nonionic surfactant system

The effect of different alkyl chains of anionic surfactants on properties of binary anionic-nonionic mixed surfactant systems was studied. These systems included ocytldodecyl-, and cetylsulfoacetates mixed with isooctyl phenol nonyl ethoxylate. The critical micelle concentration of mixed surfactants shifted to lower values compared to those of the single anionic surfactants. Effectiveness values increased with decreases in the mole fraction of anionic surfactants. The negative values of interaction parameter (β) increased with increases in the chain length of anionic surfactants.     

Micellization and Adsorption Behaviors of New Reactive Polymerizable Surfactants Based on Modified Nonyl Phenol Ethoxylates

The synthesis and characterization of a series of polymerizable surfactants based on alkyl phenol ethoxylate backbone and carboxylic or anhydride chain ends were investigated. Surface activities of these polymerizable surfactants were investigated to correlate their structure and their performances. The new bifunctional surfmers were prepared by reacting polyoxyethylene 4-nonyl-2-propylene-phenol nonionic reactive surfactants with maleic anhydride. The chemical structure of the prepared surfactants was characterized by ¹³C and ¹H NMR analyses. The surface activities of the modified polymerizable surfactants were measured from the adsorption isotherm measurements which were determined from the relationship between the concentrations and surface tension of surfactants in aqueous medium at different temperatures. Critical micelle concentration (CMC) values were determined for water soluble surfactants. It was found that CMC decreases with the incorporation of the anhydride and acid groups in the chemical structure of polyoxyethylene 4-nonyl -2-propylene-phenol nonionic surfactant. surface-active parameters such as area per molecule at the interface (A _min), surface excess concentration (Γ_max) and the effectiveness of surface tension reduction (π_CMC) were measured from the adsorption isotherms of the modified surfactants. Some thermodynamic data for the adsorption process were calculated and discussed. The data indicated that the new surfmers are more reactive than the simple polyoxyethylene 4-nonyl-2-propylene-phenol and more adsorbed at interfaces. We have performed a preliminary experiment to explore the emulsification efficiency of the newly synthesized reactive surfactants in equal volume oil–water emulsions. Different emulsion types and stabilities were obtained.     

Comparison of polarity parameters for glass fibers obtained by inverse gas chromatography and solvatochromism

Glass fibers with different surface properties (differently sized and unsized) have been investigated by means of inverse gas chromatography (IGC) at infinite dilution as well as by UV/Vis spectroscopy of solvatochromic probe dye molecules. Surface acid–base parameters obtained from the specific energies of adsorption of polar probes using IGC were compared with empirical polarity parameters obtained from shifts in the UV/Vis absorption maxima of adsorbed solvatochromic probe dyes. Both methods give useful information on surface characteristics. Solvatochromism seems to be suitable for a quick sizing characterization and, therefore, this method may become a significant surface analytical tool in the field of adhesion compared with the established IGC methodology.     

Ethylene oxide oligomer distribution in nonionic surfactants via high performance liquid chromatography (HPLC)

A high performance liquid chromatography (HPLC) method using adsorption columns combined with linear gradient elution has been developed for the determination of ethylene oxide (EO) distribution in nonionic surfactants. The quantitative ethoxylate adduct distribution in single-carbon-number and mixed-carbon-number primary alcohol-based samples can be obtained. The HPLC method is also applicable for determining the molar EO distributions in diverse ethylene oxide adduct compounds such as alkylphenol ethoxylates, branched alcohol ethoxylates and secondary alcohol ethoxylates. Nonionic surfactant samples containing adducts up to 25 mol have been successfully separated and the individual adducts quantitated.     

Morphology,structure, and conductivity of polypyrrole prepared in the presence of mixed surfactants in aqueous solutions

Polypyrrole (PPy) was prepared from different mixed‐surfactant solutions with ammonium persulfate as an oxidant. Three types of combinations were selected, including cationic/anionic, cationic/nonionic, and anionic/nonionic mixed‐surfactant solutions. The surfactants used in the experiments included cetyltrimethylammonium bromide (cationic surfactant), sodium dodecyl sulfate (anionic surfactant), sodium dodecyl sulfonic acid salt (anionic surfactant), poly(vinyl pyrrolidone) (nonionic surfactant), and poly(ethylene glycol) (nonionic surfactant). The morphology, structure, and conductivity of the resulting PPy were investigated in detail with scanning electron microscopy, Fourier transform infrared spectra, and the typical four‐probe method, respectively. The results showed that the interaction between the different surfactants and the interaction between the surfactants and the polymer influenced the morphology, structure, and conductivity of the resulting polymer to different degrees. The cationic surfactant favored the formation of nanofibers, the addition of anionic surfactants produced agglomeration but enhanced the doping level and conductivity, and the presence of a nonionic surfactant weakened the interaction between the other surfactant and the polymer in the system. In comparison with the results for monosurfactant solutions, the polymerization of pyrrole in mixed‐surfactant solutions could modulate the morphologies of PPy, which ranged from nanofibers of different lengths to nanoparticles showing various states of aggregation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1987–1996, 2007