AOS — An anionic surfactant system: Its manufacture,composition, properties,and potential application

Several sulfonation parameters, believed to be critical to the manufacture of good quality a-olefin sulfonate (AOS), are related to product color and conversion. The interfacial properties for single carbon number AOS and the major components comprising AOS are investigated. Results, based on surface activity, indicate that AOS in the molecular weight range from C₁₄ through C₁₈ should be of value in formulating efficient cleaning agents. The data show that AOS is more effective for lowering Crisco®/solution interfacial energy than the more commonly used surfactants. The alkene-1-sulfonate component of AOS was found to be most effective in lowering interfacial energy with the hydroxyalkane-1-sulfonate component being significantly less effective but still more effective than alcohol ether sulfate or linear alkylbenzene sulfonate of comparable molecular weight. Hand dishwashing efficacy was found greatest for the hydroxyalkane-1-sulfonate component of AOS, but combinations of hydroxyalkane-1-sulfonates and alkene-1-sulfonates were shown to be synergistic for laundering applications. The presence of the -OH group in the hydroxyalkane sulfonate structure was shown to increase solubility and lower surface activity significantly more than the presence of unsaturation in the alkene sulfonate. Long, single branching in the a-olefin sulfonate and random internal olefin sulfonate are shown to reduce drastically the surface activity. The hydroxyalkane and alkene-1-sulfonates were rapidly biodegraded. Disulfonates and long, singly branched sulfonate were more slowly degraded. Both 1,3-sultones and 1,4-sultones were found to biodegrade rapidly.     

A mechanistic approach to the thermal degradation of α-olefin sulfonates

Determination of the thermal stability of α-olefin sulfonates (AOS) via the conventional activation energy approach was found to be impractical because of the difficulties arising from the fact that α-olefin sulfonates are mixtures of hydroxyalkane sulfonates and alkene sulfonates. Each of these components of AOS was studied independently and found to follow a complicated thermal degradation path. We found that the thermal degradation of hydroxyalkane sulfonate is a base-catalyzed process. At elevated temperatures, hydroxyalkane sulfonates are first converted into an intermediate which is still surface active before degrading further to a non-surface active product by a second mechanism. The rate-determining step of the degradation process was found not to involve a cleavage of the C-S bond as observed for other types of sulfonates. Our work indicates that the first step of the thermal degradation of alkene sulfonates involves isomerization of double bonds followed by cleavage of the C-S bond. The thermal degradation of alkene sulfonates is catalyzed by acids.     

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.     

Gas chromatographic analysis for alpha-olefin sulfonate

The separation and determination of alkene sulfonate and hydroxyalkane sulfonate, and the carbon chain distribution of the lipophilic groups of long chain alpha-olefin sulfonates (C₁₄ to C₁₈) were studied by means of gas chromatography. Samples were hydrogenated initially, and converted to sulfonyl chlorides for gas chromatographic analysis. Using a glass column, 4 mm i.d. and 2.5 m long, packed with Silicon SE-30, 3% on 60 to 80 mesh Chromosorb WAW treated with hexamethyldisilazane, a 0.3 to 0.6 μl sample, as 10% carbon tetrachloride solution, was injected directly on the column, and alkane and monochloroalkane sulfonyl chloride were determined as alkyl chloride and alkyl dichloride, respectively. Minimization of further decomposition, improvement of peak separation and reproducibility were accomplished by this procedure. The method was applied to alpha-olefin sulfonates produced commercially from C₁₄ to C₁₈ alpha-olefins.     

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.     

Ultimate biodegradation studies of α-olefin sulfonates

Single carbon cut α-olefin sulfonates (AOS) having 12, 14, 16 and 18 carbon chain lengths and several of their blends were prepared from high-quality α-olefins by continuous SO₃ sulfonation in a laboratory falling film reactor. The ultimate biodegradability of these products was studied using a modified shake flask procedure with CO₂ evolution as the major biodegradability criterion. For comparison, commercial samples of a modified Ziegler-based AOS, linear alkylbenzene sulfonates (LAS), and an alcohol ethoxysulfate (AEOS) were included. The results showed the AOS products bio-degraded to CO₂ more completely than LAS and slightly less extensively than AEOS. CO₂ evolution decreased slightly in amount and rate as AOS carbon chain length increased in the C₁₄ to C₁₈ range. Presented at the AOCS meeting, May 1977, New York City.     

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.     

Recent findings and experiences with alpha olefin sulfonates

In the sulfonation and sulfation of alpha olefin (AO), linear alkylbenzene (LAB), and alcohol ethoxylate (AE), improved reaction yields and products’ color were obtained by using the TO-Reactor recently developed in Lion Fat & Oil Co., Ltd., compared with those obtained in a conventional falling-film type reactor. These improvements especially were remarkable in the case of AO, so that light-colored alpha olefin sulfonate (AOS), having improved performance properties, was obtained without bleaching. For the performance tests, AOS was evaluated in several systems, together with some other surfactants, alcohol sulfate (AS), alcohol ethoxy sulfate (AES), linear alkylbenzene sulfonate (LAS), and alpha-sulfo fatty acid methyl ester (a-SEMe). AOS was one of the most useful surfactants for heavy duty powder detergents of low phosphate formulation because of its good detergency and foaming power, rinsing property, and free flowing property. Thus, bright white heavy duty powder detergents, containing 8% of P₂O₅, were developed with AOS (nonbleached), AES, LAS, sodium pyrophosphate (TSPP), and some other ingredients, which have been marketed in the household cleaning products field in Japan since 1976.     

α-烯烃磺酸盐在液体洗涤剂中的应用

介绍了采用气相三氧化硫法生产的α-烯烃磺酸钠在液体洗涤剂配方中的应用。通过正交设计说明,影响黏度的最重要因素是氯化钠的质量分数。考察了不同碳数AOS对液体洗涤剂黏度的影响以及AOS与AES复配后液体洗涤剂去污力、调黏度和泡沫性能的区别,综合应用实验结果表明,AOS适合用于液体洗涤剂中。     

Level and position of unsaturation in alpha olefin sulfonates

A comparison of the levels of unsaturation in α-olefin sulfonates (AOS) and related derivatives determined by iodination, bromination and hydrogenation techniques showed that quantitative hydrogenation is the only method having wide applicatbility. Although halogenation methods frequently give results in agreement with hydrogenation data, they can show variations with reaction time and composition of the sample. Unsaturation in sulfonate methyl esters could not be determined by halogenation. The amount of †¹-isomer in alkene sulfonate sodium salts determined by oxidative cleavage with periodate-permanganate was always low compared to that determined by NMR. Oxidative cleavage of the sulfonate methyl esters gave †¹-isomer levels in agreement with NMR results.     

New household detergent based on AOS

The synthetic detergent industry is one of the fastest growing industries in Japan. Its production, together with soap, is estimated to be almost 2 billion pounds in 1970. In addition to this increased production, quality modification in terms of biodegradability is now being undertaken. Alpha olefin sulfonate (AOS) has been known since the 1930’s, but only within the last two years has it been highlighted for commercial interest as a detergent material due to progress in sulfonation technology as well as commercial availability of alpha olefins. To make use of AOS as an active ingredient for formulation of heavy duty household granules, several properties of AOS itself or of the built detergent were studied in comparison with linear alkylate sulfonate (LAS), alkylbenzene sulfonate (ABS) and alcohol sulfate (AS). AOS was proved to be a potentially economical detergent material having as good performance and better biological properties than LAS or AS and better biodegradability than LAS. It has been marketed since 1967 in Japan as the first AOS-based household heavy duty granular detergent. It has been accepted by the housewives as the most efficient detergent and has become the best selling brand. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April 1, 1968.     

石蜡裂解α-烯烃制备AOS表面活性剂

以蜡裂解α-烯烃(AO)为原料制备了α-烯基磺酸盐(AOS)。所涉及的主要技术问题是:原料蜡裂解α-烯烃的精制处理,采用发烟硫酸为磺化剂的磺化工艺的优化。实验数据表明,采用蜡裂解AO为原料是可以生产 AOS的;其产物与市售AOS(采用乙烯齐聚α-烯烃合成)相比,色泽深、未磺化物含量高,然而实验室产品具有与市售AOS相当的表面张力,且发泡性能优于市售AOS。     

Performance Comparison Between Internal Olefin Sulfonates and Alpha Olefin Sulfonates

Comparison of surface and interfacial properties of internal olefin sulfonates (IOS) and alpha olefin sulfonates (AOS) shows that hydrocarbon chain branching has a significant influence on interfacial properties at the air–water, pentadecane–water and parafilm–water interfaces. The isomeric branched IOS shows a higher critical micelle concentration and are more effective in reducing the surface tension at the air–water interface by occupying a larger area per molecule. IOS exhibits better dynamic air–water interfacial properties due to a lower meso-equilibrium surface tension. The equilibrium interfacial tensions for AOS and IOS have no remarkable difference at the pentadecane–water interface. The water wettability and electrolyte tolerance are enhanced with branched hydrocarbon chain olefin sulfonates.     

AOS生产反应机理描述及相关工艺计算

简述了α-烯基磺酸盐(AOS)的特性,通过对AOS磺化反应机理的分析,就反应过程物料组成及相关控制指标进行了理论计算,提供了一系列理论数据,阐述了AOS生产工艺控制关键点。     

Use of high-active alpha olefin sulfonates in laundry powders

Alpha olefin sulfonates (AOS) have been used successfully for many years in laundry and personal-care products throughout Asia. Among their documented positive attributes are good cleaning and high foaming in both soft and hard water, rapid biodegradability, and good skin mildness. AOS has commonly been marketed as approximately 40%-active aqueous solutions. However, with the increased importance of compact powder detergents produced by processes other than spray drying, high-active forms of AOS including 70%-active pastes and 90+%-active powders are now being utilized for that product sector. In this regard, the rheological properties of non-Newtonian AOS and AOS/additive pastes at relevant process temperatures were measured and found potentially suitable for agglomeration processes. Also, the relationship of AOS powder particle size to surfactant solubility at various wash conditions was examined to allow determination of the optimal size for both detergency and processing of laundry powders. Both paste rheology and powder morphology are critical factors for the successful use of high-active AOS in compact powder detergents.     

Separation and quantitation of alkene and hydroxy alkane sulfonates by thin layer chromatography

In the production of detergent range olefin sulfonates a rapid and relatively simple method for the analysis of compounds produced is desirable. This paper describes a thin layer chromatographic technique for the separation and quantitation of the sodium salts of alkene monosulfonates and disulfonates and hydroxy alkane monosulfonates and disulfonates. The separation is accomplished on tracked, unactivated sulfate-impregnated Silica Gel G layers. Standard equilibrated developing tank conditions are employed in conjunction with a developing solvent of chloroform-methanol-sulfuric acid. Visualization of the compounds is based on their suitability for charring by heat and SO₃ fumes resulting from fuming sulfuric acid which is smeared on the inner sandblasted surface of a charring lid. The charred compounds are quantitated using a scanning photodensitometer. Areas of resultant peaks are calculated and related to composition of the sample.     

Surface Dilational Rheology,Foam, and Core Flow Properties of Alpha Olefin Sulfonate

The surface tension, surface dilational rheology, foaming and displacement flow properties of alpha olefin sulfonate (AOS) with inorganic salts were studied. The foam composite index (FCI), which reflects foaming capacity and foam stability, is used to evaluate foam properties. It is found that sodium and calcium salts can lead to decreases in AOS surface tension, critical micelle concentration, and molecular area at the gas–liquid interface. Sodium ions reduce the surface dilational viscoelasticity (E) and FCI of AOS, while calcium ions can enhance the E of AOS and make the FCI of AOS reach a maximum. In the solution containing calcium and sodium ions, the FCI of AOS is improved. Crude oil reduces the FCI of AOS. Injection pressure and displacing efficiency of AOS alternating carbon dioxide (CO₂) injection are higher than injections of water alternating with CO₂ or CO₂ alone in low permeability cores.     

烯基磺酸盐的开发,生产,性能及其应用

本文综述了α－烯基磺酸盐的开发,生产过程,产品性能及其在家用洗涤剂中的应用。     

Precipitation of anionic surfactants in the presence of sodium oleate and calcium ions

Precipitation of anionic surfactants, linear alkylbenzene sulfonate (LAS) and alpha olefin sulfonate (AOS), by calcium ions was studied in the presence of sodium oleate. Lather stability was determined by the Ross-Miles method, precipitation was followed by measuring the optical density (OD), and equilibrium surface tension (EST) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the nature of the precipitate formed. For the 5 mM LAS-0.7 mM oleate system, lather was unstable, and the OD was high in the 2–5°FH region of calcium hardness, while at higher calcium hardness levels, lather was stable and the turbidity of solutions decreased. On the other hand, in the 5 mM AOS-0.7 mM oleate system, lather was unstable throughout the calcium hardness region studied (0–20°FH). Also, the turbidity build-up was much higher in the AOS system than in the LAS system. Analysis of the precipitates formed in these systems by FTIR spectroscopy indicated that the precipitate from the AOS system had an additional band at 1190 cm⁻¹, corresponding to the sulfonate group. These results, together with the EST data, confirm that the precipitate formed in the LAS system between 2–5°FH calcium is calcium oleate, and that formed in the AOS system is likely to be calcium (AOS) oleate. It is tempting to hypothesize that the similarity of AOS and oleate in chainlength could be responsible for the coprecipitation of AOS and oleate with calcium, whereas LAS, which has a larger headgroup with a benzene ring and two smaller chains (average length is C8) is unlikely to precipitate with the oleate.     

Ethersulfonate auf Basis ungesättigter Fettalkohole – eine neue Tensidklasse

Ether Sulfonates Basing on Unsaturated Fatty Alcohols – A New Tenside Type Alkenylpolyglycolalkylethers of the general form R-O-(CH₂-CH₂-O)_n-R′ (R = unsaturated fatty alkyl residue; R′ = alkyl group C₁-C₁₀) lead after sulfonation with a SO₃ air mixture, subsequent neutralization and alkaline pressure hydrolysis to a mixture of ether sulfonates. Sulfonation was carried out in a laboratory fall film reactor and optimized with respect to the SO₃/ ether ratio. Basing on the thus obtained results this reaction could be carried out in a continuous pilot sulfonation plant (through put: 50 kg ether/h). The new ether sulfonates are a very variable tenside type where different properties of application can be chosen in dependence on the ratio of hydrophobic to hydrophilic molecule parts.