Effect of carbon chain and phenyl isomer distribution on use properties of linear alkylbenzene sulfonate: A comparison of ‘high’ and ‘low’ 2-phenyl LAS homologs

Phenyl isomer distributions, within current commercial limits of HF and A1C13 linear alkylbenzene sulfonates (LAS), have little effect on dishwashing performance in light-duty liquids (LDL), detergency performance in heavy-duty powders (HDP), and interfacial tension value. The most important factor in determining performance differences among commercial LAS samples is carbon chain homolog distribution. Both HF and A1C1₃ LAS perform equally well and can be used interchangeably in high-performance products. The optimum for foam stability in light-duty liquids shifts towards shorter alkyl chain length as water hardness increases. At 0 ppm water hardness the optimum occurs at C₁₃: at 50–150 ppm the optimum moves to C₁₁ and C₁₂; and above 150 ppm the optimum shifts to include C₁₀, C₁₁ and C,₁₂. The detergency performance optimum range in a phosphate built heavy-duty powder at 50 and 150 ppm water hardness includes the C₁₂, C₁₃ and C₁₄ alkyl chain lengths. In a nonphosphate built powder the optimum is similar at 50 ppm hardness to that of a phosphate built powder, but shifts at 150 ppm hardness to include C₁₁, C₁₂ and C₁₃.     

Influence of Hydrocarbon Chain Branching on Foam Properties of Olefin Sulfonate with FoamScan

The influence of surfactant structure on foam properties of internal olefin sulfonate (IOS) and alpha olefin sulfonate (AOS) in aqueous solutions was estimated from measurements of the foamability, foam stability, and foam morphology, as obtained from conductivity and image analyses techniques. It was found that the foamability and foam stability of C_16–18 AOS are higher compared to that of C_16–18 IOS, indicating that hydrocarbon chain branching decreases the foamability and foam stability. The foamability and foam stability are enhanced with increasing surfactant concentration, which increases the adsorbed quantity of surfactant molecules at the air–water interface. The influence of hydrocarbon chain branching on foam morphology was also investigated. It was found that foam cells produced by branched chain C_16–18 IOS are larger than the foam cells generated by straight chain C_16–18 AOS.     

Performance of sulfoxylated fatty acid methyl esters

Sulfoxidation of fatty acid methyl esters with SO₂, O₂, and ultraviolet light of appropriate wavelength has led to the synthesis of methyl esters sulfonates or sulfoxylates known as Φ-MES because of the possible random position of SO₃ group in the alkyl chain. This work describes experimental measurements of physical properties such as solubility and viscosity of sodium Φ-MES water solutions. Amphipathic properties such as surface tension, critical micelle concentration, wetting and foaming powers were measured as well and compared to linear alkylbenzene sodium sulfonate (LAS). Finally, stability to water hardness, dishwashing test, and detergency performance were evaluated. Expectedly, these products may be used as LAS partners either in heavy-duty powders or in hand dishwashing liquids. Experimental results on Φ-MES of varying carbon number indicate that C₁₆ is the optimal carbon chain length.     

Straight-chain alkylbenzenes: Structure and performance property relations III. Light-duty dishwashing formulations

A relationship between mixtures of straightchain alkylbenzene sulfonates and their performances in light-duty dishwashing formulations has been established through studies of many pure isomers and isomer mixtures in both liquid and powder systems. The foam performance characteristics are shown to be directly related to carbon chain length, phenyl position, and water hardness in a readily calculable manner. Solubility studies on pure isomers are also reported. Presented at the AOCS Meeting, Houston, April 1965.     

Alpha olefin sulfonates from a commercial SO3-Air reactor

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

Straight-chain alkylbenzenes: Structure and performance property relations

An intensive study of the mass spectral characteristics of straight-chain alkylbenzenes has been made in conjuction with their ultimate performance as sulfonates in heavy duty formulations. Two variables of the alkylates, carbon-chain length distribution (which fixes the mean mol wt) and phenyl position on the chain, have been successfully related to the observed dishwashing performances. Formulas are given which allow accurately predicting this performance criteria. The important role of phenyl position is illustrated by a detailed study of each phenyl isomer in the tetradecylbenzene series.     

Effect of Fine Bubbles on Removal of Linear Alkyl Benzene Sulfonate Surfactant during the Rinsing Stage of Laundry Washing

The use of fine bubbles is a promising approach to remove surfactant efficiently during the rinsing process of clothing, to fulfill a requirement. Therefore, the influence of fine bubbles on the removal performance of surfactant from cloth during the rinse process of pulsator washing machine (top loading type) was investigated. The test apparatus was assembled by connecting a microbubble generation tank and a small washing machine with tubes and circulating fine bubble water to a small washing machine. Swatches of cloth with a specified amount of linear alkylbenzene sulfonate (LAS) adsorbed from aqueous solution, were rinsed with tap water, and the LAS concentration in the rinse water was examined with an HPLC system equipped with a high-precision fluorescence detector. The average bubble diameter of the fine bubble water used was 0.13–1.4 μm. In the rinsing experiment, no difference was found in the final LAS removal efficiency between water with and without bubbles; but the former increased the LAS removal rate during the initial stage of rinsing. This tendency was particularly noticeable when the stirring power of the washing machine was weak. Therefore, it was concluded that the fine bubble effect on the removal of the surfactant is mainly a kinetic effect rather than an equilibrium effect.     

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

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

新型餐具洗涤剂的研制

用正交实验优化了餐具洗涤剂的配方,对其去污力和泡沫性能进行了测定。结果表明,最佳工艺条件为:原料比例LAS∶AES∶6501=12∶9∶1(质量比),在温度50℃混合1 5h。产品泡沫丰富,稳定性好,去污力强。     

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

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

Impact of molecular structure on the performance of methyl ester ethoxylates

Methyl ester ethoxylates are a new class of ethylene oxide (EO)-derived surfactants. Little is known about the impact of structural variations on their performance properties. The effects of carbon chain length, EO content, the degree of unsaturation of the methyl ester feedstock, and feedstock purity were examined for their impact on both physical properties and surfactant performance properties. Physical properties examined included surface properties (surface tension, critical micelle concentration, surface excess adsorption), melting point, water solubility, viscosity, foam stability, color, clarity, and odor. The impact of molecular structure on performance was examined for various applications, including laundry detergents, dishwashing detergents, and hard-surface cleaners. Presented at the AOCS Annual Meeting & Expo, May 1997, Seattle, Washington.     

Synthesis and surface measurements of surfactants derived from dehydroabietic acid

Dehydroabietates with poly(ethylene oxide) chains of average m=12, 17, and 45 units [DeHab(E) _m ] were synthesized. The adsorption at the liquid-vapor interface was measured, and the adsorbed amount and critical micelle concentrations (CMC) were determined. The foamability, the foam stability, wetting properties, and cloud points, with and without salt content, were studied. The results were compared with common linear alkyl ethoxylates, nonylphenol ethoxylates, and cholesterol ethoxylates. The dehydroabietic acid as hydrophobe was found to result in the same CMC as a linear dodecyl chain. DeHab(E)₄₅ was found to be insoluble above 400 mg/L, but the surface tensions at lower concentrations were similar to those of the C_11–13E_38–40 surfactants, which exhibit CMC in aqueous media. The foaming behavior of the DeHab(E)₁₂ and DeHab(E)₁₇ surfactants was about the same as for common linear C _n E _m surfactants. The foamability as well as the foam stability increased with ethylene oxide (EO) chain length. The cloud point was depressed by increased salt concentration and increased with the number of EO units in the head group. The cloud point was significantly lower than for the corresponding surfactant with a dodecyl chain with similar EO chain length. The wetting results, obtained by measuring the contact angle at similar surface tensions, indicate that surfactants of the DeHab(E) _m type are more efficient wetting agents than both disaccharide sugar surfactants and C _n E _m type surfactants.     

Extrusion foaming of polystyrene/carbon particles using carbon dioxide and water as co-blowing agents

Carbon particles such as platelet-like graphite (GR), spherically shaped activated carbon (AC), and tubular carbon nanofiber (CNF) were used as additives in extruded polystyrene (PS) foams with carbon dioxide (CO₂) and water as co-blowing agents. It was found that GR is the best additive for improving the thermal insulation performance of CO₂ based foam samples because of GR’s good absorption and reflectivity of infrared (IR) radiation. However, when the GR concentration was higher than 0.5 wt.%, the extruded foams exhibited large bubbles in the center of the foam and the extrusion line became unstable. By adding water carried by AC as a co-blowing agent, it was able to decrease the temperature in the center of the extruded foam, which successfully eliminated the bubble problem and achieved stable foam extrusion with good control of the foam density and cell morphology. Moreover, water carried by AC could also improve the mechanical performance of extruded foams containing CNF or GR. Water was not found in the extruded foams and the presence of water during extrusion did not affect the molecular weight and glass transition temperature of PS. Our results showed that a combination of AC as a water carrier and GR as an absorber and reflector of IR radiation can produce CO₂ based PS foams with good thermal insulation and mechanical properties, particularly with the presence of a small amount of CNF nanoparticles.     

Monoenoic fatty acids in human brain lipids: Isomer identification and distribution

The carbon chain length distribution and the double bond positional isomer composition of the monoenoic fatty acids of the lipids of total human brain tissue have been determined using gas chromatography and gas chromatography/mass spectrometry of the fatty acid methyl and picolinyl esters. The even chain length monoenoic C₁₆ to C₂₈ fatty acids contain predominantly two positional isomer series, the n−7 and n−9cis homologues, whose relative proportion varies significantly with chain length. The odd chain length long-chain fatty acids consist of n−8 and n−10 isomers, whereas the odd chain length very long-chain (more than 22 carbon) fatty acids are n−7 and n−9 isomers.     

Relationship of structure to properties of surfactants. 15 Isomeric sulfated polyoxyethylenated Guerbet alcohols

The properties at 25°C in aqueous 0.1M NaCl at the aqueous solution/air, aqueous solution/hexadecane, and aqueous solution/hydrophobic solid interfaces of two isomeric Guerbet alcohol-derived surfactants C₈H₁₇CH(C₆H₁₃)CH₂(OC₂H₄)₅SO₄Na, one in which the octyl and hexyl groups are both linear (L isomer), the other in which they are both highly branched (B isomer), have been investigated and compared in some cases with commercial sodium linear dodecylbenzene-sulfonate (LAS). The cmc value increases, the pC₂₀ value decreases, and the ΔG^o _ad value becomes less negative in the order: L isomer—B isomer—LAS. The minimum area/molecule at the aqueous solution/air interface increases in the order: LAS≪L isomer<B isomer. The L isomer is slightly more hydrophobic than the B isomer, and both are considerably more surface-active than LAS. The greater steric inhibition to micellization in the B isomer results in the lowest minimum surface tension. Both isomers have similar minimum interfacial tension values against hexadecane. Unusually small minimum area/molecule values for the two isomers at the aqueous solution/hydrophobic solid interface may indicate multilayer adsorption there. Both isomers are more efficient at reducing the contact angle than LAS. Mixtures of the B isomer with the corresponding unsulfated Guerbet alcohol show only weak interaction between the two. No synergism in surface (or interfacial) tension reduction efficiency or micelle formation exists at either the aqueous solution/air or aqueous solution interface but the mixture does show synergism in surface (or interfacial) tension reduction effectiveness, yielding a surface tension value of 28.2 dynes/cm, and an interfacial tension value of 0.1 dyne/cm against hexadecane. Draves wetting times increase in the order: B isomer<LAS<L isomer, and Ross-Miles initial foam heights decrease in the order B isomer ≈LAS>L isomer. Presented in part at the American Oil Chemists’ Society meeting in Cincinnati, May, 1989.     

“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.     

Synthesis and Some Surface Properties of Glycine-Based Surfactants

A new group of anionic surfactants, namely sodium salts of secondary alkanesulfonamidoacetic acid, were synthesized using n-alkanesulfonyl chlorides as starting materials. These surfactants, having the formula: R–SO₂–NH–CH₂–COONa, with R = C₁₂, C₁₄, C₁₆ and C₁₈, were obtained in a simple way with quantitative yields. Different chain lengths and positional isomers of this new type of surfactants are expected to present differences in surface properties and foamability. The surface properties including critical micelle concentrations and minimal surface tensions γ_min were determined for each prepared surfactant using surface tension measurements with a Wilhelmy plate. Surface excess and minimum area per molecule at the air–water interface were determined for different concentrations at 25 and 50 °C using the Gibbs equation. The foaming power was also determined by the Bartsch method, and the results obtained were compared to those of a commercial surfactant, the linear alkylbenzenesulfonate. The stability of the foam formed was also evaluated. As expected, these surfactants exhibit good surface properties and show good foaming power.     

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

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

Linear alkylbenzene sulfonates in the prevention of vagrant dye pick-up on polyester textile fabric during laundering

The unwanted pick-up of low levels of vagrant dyes during washing of textile fabrics can be a significant contributor to long-term polyester appearance degradation. Fabric appearance loss from pick-up of small quantities of a standard yellow dye are measured on both optically brightened and unbrightened polyester. Linear alkylbenzene sulfonate (LAS) surfactant micelles act as effective dye scavengers, reducing the level of dye pick-up by the fabric substantially. The efficacy of LAS as a dye scavenger is quantified as a function of alkyl chain length and use concentration. Dye scavenging ability per unit weight of LAS increases with increasing molecular weight and decreasing critical micelle concentration (cmc). Dye scavenging of up to 80% of the transferable dye is achieved at high LAS concentrations. Results with C₉, C₁₁, C₁₃ and C₁₅ single homolog alkyl chain lengths, and with several mixed chain length blends are presented. Presented at the AOCS symposium on “Surfactants in Textiles,” New Orleans, May 1981.     

Fabrication and mechanical properties of carbon fibers/lithium aluminosilicate ceramic matrix composites reinforced by in-situ growth SiC nanowires

To improve the mechanical properties of carbon fibers/lithium aluminosilicate (C_f/LAS) composites, C_f/LAS with in-situ grown SiC nanowires (SiC_nw-C_f/LAS) were prepared by chemical vapor phase reaction, precursor impregnation, and hot press sintering, consecutively. The effect of multi-scaled reinforcements (micro-scaled C_f and nano-scaled SiC_nw) on the mechanical properties was investigated. The phase composition, microstructure and fracture surface of the composites were characterized by XRD, Raman Spectrum, SEM, and TEM. The morphology of SiC_nw has a close relation with the content of Si. Microstructure analysis suggests that the growth of SiC nanowires depends on the VLS mechanism. The multi-scale reinforcement formed by C_f and SiC_nw can significantly improve the mechanical properties of C_f/LAS. The bending strength of SiC_nw-C_f/LAS reaches to 597 MPa, achieving an increase of 19% to C_f/LAS. Moreover, the samples show a maximum fracture toughness of 11.01 MPa m^1/2, achieving an increase of 46.4% to C_f/LAS. Through analysis of the fracture surface, the improved mechanical properties could be attributed to the multi-scaled reinforcements by the pull-out and debonding of C_f and SiC_nw from the composites.