A contribution to understanding secondary reactions in linear alkylbenzene sulfonation

Modern industrial sulfonation of linear alkylbenzene (LAB) in falling film reactors produces p-alkylbenzene sulfonic acid (HLAS), which is usually neutralized with caustic soda (NaOH) and used in detergent formulations. During the sulfonation process, other products such as anhydrides and sulfones are also formed. Four reactions are proposed to occur during aging and hydrolysis. As a consequences, approximately 25% of sulfones and 75% of unreacted LAB are removed during aging and are transformed into additional active matter. Anhydrides are completely eliminated during hydrolysis. On the other hand, sulfones formed during the process are difficult to remove once formed. The goal of this work was to optimize the various operating conditions of the sulfonation process and to understand the various secondary reactions that occur therein so as to obtain a maximal active ingredient concentration in the final sulfonated product and a minimum of unsulfonated matter. Formation of sulfones can be minimized by using an SO₃/LAB molar ratio slightly lower than the theoretical optimum.     

烷基苯生产工艺对烷基苯磺酸钠物化性能的影响

介绍了烷基苯生产工艺的发展动向以及几种已工业化的烷基苯工艺生产的烷基苯组成及相应的烷基苯磺酸盐的物化性能，认为固定床烷基化工艺是今后研究和发展的方向。     

Alkylaromatics in Detergents Manufacture: Modeling and Optimizing Linear Alkylbenzene Sulfonation

Linear alkylbenzene sulfonic acid (ASA) is the main ingredient of many commercial formulations for industrial and domestic synthetic detergents. The current industrial ASA production method includes sulfonation of linear alkylbenzene (LAB) with sulfur trioxide in tubular falling‐film reactors. The present study investigates the influence of light alkylaromatics on the efficiency of ASA production. After dealkylation and polymerization, these aromatic compounds form viscous components in the sulfonation reactor. This increases the organic liquid viscosity and disrupts the uniformity of sulfonation. We present the results of IR analysis of the LAB and ASA samples, which indicate that the viscous components are sulfones that are part of the unsulfonated matter. With due consideration of the sulfonation process reaction network, we developed a mathematical model for a sulfonation reactor considering the alkylaromatics content in the feed flow and its effect on the reaction rates. The results allowed the improvement of sulfonation process in terms of increasing the number of days between the reactor washings. The sulfur flow rate increased from 371.7 to 380.9 kg h^?1 at the end of this period for the aromatics content in LAB of 4 wt.% and from 372.1 to 380.1 kg h^?1 for aromatics content in LAB of 6 wt.%. The proposed modifications of the process modes can increase the SO₃ conversion up to 98%.     

直链烷基苯磺酸异丙胺盐的性能及其在餐具洗涤剂中的应用研究

对直链烷基苯磺酸异丙胺盐(HIPN)的表面张力、润湿力、乳化力、发泡能力等基本性能进行研究,并与洗涤剂常用阴离子表面活性剂直链烷基苯磺酸钠(LAS)、脂肪醇聚氧乙烯醚硫酸钠(AES)和α-烯基磺酸钠(AOS)进行了对比,研究了HIPN在手洗餐具洗涤剂配方中的表现。结果表明,在餐具洗涤剂中HIPN具有优异的增稠性能,能全部代替或者部分代替LAS和AES,实现和AOS复配的低成本无二烷配方。     

Linear Alkylbenzenes Sulfonation: Design of Film Reactor and its Influence on the Formation of Deactivating components

Linear alkylbenzene sulfonic acid (ABSA) is a valuable product of inorganic chemistry that is used to obtain linear alkylbenzene sulfonates. The current method for industrial production of ABSA includes sulfonation of linear alkylbenzene (LAB) with sulfur trioxide in tubular falling film reactors. In this work, we analyze the dependence of the dynamics of the deactivating components formation (tetralines and sulfones) on the structural parameters for a multi-tube film sulfonation reactor. To achieve this, we used an unsteady-state mathematical model that considers the feedstock composition and the change in the reaction medium activity. We determined that the film sulfonation reactor of optimal construction has 40 tubes of diameter of 43 mm. It was revealed that with an increase of the LAB supply to the reactor tube, the mass transfer coefficient also increases. For LAB flows of (95∙10⁻⁵) and (2.86∙10⁻⁵) m³ s⁻¹ per tube, the mass transfer coefficient is (1.73∙10⁻²) m s⁻¹ and (2.08∙10⁻²) m s⁻¹, respectively.     

Analysis of Minor Products in Linear Alkylbenzene Sulfonation. Comparison Between the Traditional Gravimetric Method and High Performance Liquid Chromatography (HPLC) Procedures Versus High Temperature Gas Chromatography (HT-GC)

During the sulfonation process of the linear alkylbenzene (LAB) other products like sulfones and anhydrides are also formed in addition to the linear alkylbenzene sulfonic acid (HLAS). Most of them are transformed in different degrees during the aging and hydrolysis steps of the overall sulfonation process [Moreno et al. (2003) J Surfactant Deterg 6(2):137–142]. The use of HPLC technique since 1988 and earlier the use of high temperature gas chromatography (HT-GC) enable the separation and quantification of all the components of the free oil (FO) of the sulfonic acids—anhydrides; LAB and sulfones. The purpose of this paper is to review the current knowledge about the free oil analysis and to discuss a new analytical procedure based on the HT-GC to quantify the free oil content. We will compare the results obtained using this new method with other analytical procedures (traditional gravimetry) and near infrared (NIR) spectroscopy.

Evaluation of the rheological properties of sulfonic acids and sodium sulfonates

Sulfonic acids of linear alkylbenzene (LAB) are converted into the corresponding sodium salts to produce the most widely used anionic surfactant worldwide, linear alkylbenzene sulfonate (LAS). Used in many industrial applications and consumer products, the physical and mechanical properties of the sulfonates are strongly dependent on the LAB manufacturing process. Until recently, commercial alkylation of benzene has employed aluminum chloride or hydrogen fluoride catalysts, but a new fixed-bed alkylation process (DETAL) has been developed with improved 2-phenyl isomer selectivity and low tetralin concentration. In order to better understand the rheology of LAS in aqueous media, a comprehensive comparative evaluation of sulfonic acids and sodium sulfonates of the three LAB process derivatives has been done using dynamic mechanical rheometry, steady shear viscometry, and X-ray diffraction for phase identification. LAB sulfonic acids are Newtonian fluids in the temperature range of 20–60°C. The neat AlCl₃, HF, and DETAL sulfonic acids are Newtonian fluids within the temperature range of 20–60°C. At 30 wt%, all three sulfonates are Newtonian at 20–60°C, and the 40 wt% AlCl₃ sodium sulfonate remains in the Newtonian regime within this temperature range. Lamellar liquid crystalline phases have been identified for the sulfonates in the concentration range of 40–60 wt% in water at 20–60°C, and a hexagonal lattice phase also has been identified for DETAL sodium alkylbenzene sulfonate at 40 wt%, 60°C. The presence of anisotropic phases results in non-Newtonian pseudoplastic behavior with time-dependent viscosity functions.     

NiO／活性炭催化氧化降解水中LAS研究

以NiO／活性炭为催化剂,并加入H2O2,催化氧化降解100mL50mg／L十二烷基苯磺酸钠（LAS）。结果表明,H2O2用量为4．9mrnol／L,温度为50℃,pH值在3～4之间,反应时间为2．0h,LAS降解率接近80％,CODMn。去除率为71.6％。     

Linear alkylbenzene

Linear alkylbenzene (LAB) was introduced in the mid-1960s as a raw material for cleaning products. Since then, continuing and explosive research on its biodegradation and on its environmental and human toxicity has been performed. The efficiency of linear alkylbenzene sulfonate as surfactant is clearly established, and it is one of the safest and most cost-effective products in widespread commercial use. The aim of the present paper is to survey the most important developments and understandings of the chemistry of LAB production and of its physical and environmental properties. The expected consequence of this analytical survey is to envisage the continuous challenges for the detergents industry in catalytic production of LAB, better control of selectivity, replacement of corrosive and mineral liquid acid catalyst by heterogeneous acid catalyst and the maintenance of competitiveness of LAB with respect to natural alcohols.     

Isolation and identification of soil bacteria resistant to surfactants in washing detergents

Linear alkylbenzene sulfonate (LAS) and polyoxyethylene lauryl ether (POLE) are the major surfactants in washing detergents. In the present study, we isolated surfactant-resistant bacteria from soil samples collected from a sports ground and a farm field. The samples were treated with 2.0% LAS or POLE at 25°C for 30 min and cultivated on agar plates at 25°C for several days, after which manifold bacterial colonies were isolated. Thereafter, we tested the ability of each bacterial isolate to resist the antibacterial activity of the surfactant. Ten LAS-resistant strains were isolated, and all were found to be Gram-negative bacteria such as Enterobacter and Pseudomonas. On the other hand, 18 POLE-resistant strains were isolated, of which 14 were Gram-positive bacteria including Bacillus and Microbacterium. Notably, one POLE-resistant strain was identified as Bacillus cereus, a potential causative agent for foodborne illness. The genera of LAS- and POLE-resistant bacteria did not overlap. Therefore, the combination of LAS and POLE could be more effective to eliminate soil bacteria from clothes and/or daily necessities.     

Effect of temperature on the biodegradation of linear alkylbenzene sulfonate and alcohol ethoxylate

The effect of temperature on the biodegradation of linear alkylbenzene sulfonate (LAS) and alcohol ethoxylate (AE) was evaluated using method OECD 303 A, Confirmatory test (Husmann units). The experiments were performed using an initial surfactant concentration of 10 mg/L and working temperatures of 25, 15, and 9°C, keeping the biodegradation units inside a thermostatic chamber. In all cases, the removal of both surfactants tested, LAS and AE, was higher than 90%, regardless of the temperature used in the test. We observed that longer acclimation periods were needed by the microorganisms at lower temperatures.     

聚合物对烷基苯磺酸钠与钙离子相互作用的影响

用浊度法研究了聚合物对烷基苯磺酸钠与钙离子的相互作用的影响,不同聚合物,如聚乙烯亚胺（ＰＥＩ）、聚乙烯吡咯烷酮（ＰＶＰ）和聚乙二醇（ＰＥＧ）在同一ｐＨ条件下的研究结果表明,ＰＥＩ比后两能更好地抑制ＬＡＳ钙盐的形成。同时一聚合物在不同ｐＨ条件下的研究发现,ＰＥＩ只有在一个适当的ｐＨ范围内,即自身具有适当的电荷密度,才能很好地发挥其上述作用。在体系中存在一定量的ＡＥＯ３条件下,也观察到了ＰＥＩ在抑制     

Formulating characteristics of high and low 2-phenyl linear alkylbenzene sulfonates in liquid detergents

Detergent range linear alkylbenzene (LAB) currently is manufactured by two different processes, using either aluminum chloride or hydrogen fluoride as the alkylation catalyst. The alkylates from the two processes are not exactly the same. Furthermore, the properties of the linear alkylbenzene sulfonate (LAS) surfactants made by sulfonation of the LABs also differ. Because LAS is used in most types of detergent products, it is important to known how the properties of each type of LAS differ. This paper compares the formulating characteristics (such as viscosity, solubility and foaming) of high and low 2-phenyl LAS in some typical household cleaning product formulations. It is concluded that the two types of LAS should not be used interchangeably without first checking carefully all the physical properties required in a product. Presented at the AOCS meeting in Honolulu, Hawaii in May 1986.     

Analysis of Linear Alkylbenzene Sulfonate in Laundry Wastewater by HPLC–UV and UV–Vis Spectrophotometry

A lack of natural water resources and an increase in the demand for fresh potable water has shifted focus to the possible reuse of recycled laundry wastewater water that is considered to be relatively clean. Organic components such as linear alkylbenzene sulfonates (LAS) are the major and most abundant contributing anionic surfactant constituents found in laundry detergents. The development and reliability of treatment methods targeted at purification of laundry wastewater necessitates a fast and accurate method for quantification of LAS. This paper focuses on a comparative study for the quantification of LAS based on traditional liquid–liquid extraction (LLE) and HPLC–UV methods. In the case of LLE, the anionic surfactant LAS complexes via ion association to a methylene blue (MB) cationic dye resulting in the formation of an anionic surfactant–methylene blue (AS–MB) complex. The AS–MB complex extracted with chloroform absorbs at a λ max of 653 nm. Optimized conditions for quantification of a single eluted LAS peak using HPLC–UV were obtained by isocratic elution on a C₁₈ column with a 95 % acetonitrile and 5 % 0.7 M acetic acid mobile phase. Both methods displayed percentage recoveries >90 % and statistically showed reproducibility and precision in the quantitation of LAS. HPLC–UV prevailed over UV–Vis as the method of choice for LAS determinations given the ease of sample preparation and applicability to a wider range of samples. Typical levels of LAS in laundry samples assessed in this study ranged between 116 and 454 mg L^?1.     

基于石化产品的表面活性剂原料——直链烷基苯的现状及前景

综述了直链烷基苯（LAB）产品的经济状况、供求状况、性价比以及符合法规方面的情况,并对其主要衍生物LAS对人体及环境的危害性作了详细的评价,最终得到了一系列的结论。     

Kinetics and practical significance of biodegradation of linear alkylbenzene sulfonate in the environment

This paper reviews the kinetics of biodegradation of linear alkylbenzene sulfonate (LAS) in engineered (wastewater treatment) and natural environment systems, focusing on work conducted in our environmental laboratories over the past 10–15 yr. Biodegradation studies were conducted in laboratory microcosms in which pure-chainlength [¹⁴C]-ring-labeled LAS homologs were used to allow complete mineralization to be assessed. In general, biodegradation rates for a series of LAS homologs (C10–C14) were comparable to each other and to values for naturally occurring materials such as sugars and fatty acids. Half-lives for LAS mineralization ranged from 1–2 d in aerobic and anaerobic sewage sludges, river water and sediments, to 1–3 wk in surface and subsurface soils and estuarine environments. The half-life for LAS degradation in different environmental compartments, relative to its residence time in these compartments, makes biodegradation a practically significant removal mechanism in a broad range of aquatic, benthic and terrestrial habitats.     

直链烷基苯磺酸钠(LAS)的生产及现状分析

介绍直链烷基苯磺酸钠(LAS)的工艺流程和产品的质量指标。概述了国内三氧化硫连续磺化技术从引进到国产化的演变过程。对国内直链烷基苯(LAB)和直链烷基苯磺酸(LAS)的生产现状进行了分析和总结,并指出国内磺酸产能的过剩应引起相关行业的注意。     

The behaviour of LAS in the environment

During the last few years a considerable amount of information about the biodegradation of linear alkylbenzene sulfonates (LASs) in real environmental situations has been made available. This paper reviews the existing LAS concentrations found today in the environment, using specific analytical techniques for this surfactant, as well as its mineralization and fate in compartments such as sludge amended soils. LAS is totally decomposed into carbon dioxide, water and inorganic sulfate without formation of stable metabolites, and no accumulation has been detected in the compartments studied. The highest degree of biodegradation (>95%) takes place in the processes (sewers and sewage treatment plants) showing the shortest half lives (1–10 h).     

SiW12/NaY固体杂多酸催化剂的微波合成及LAS降解性能研究

以微波辐射方法合成了NaY分子筛、二氧化锆和二氧化钛不同载体负载磷钨酸、磷钼酸、硅钨酸不同杂多酸的固体酸催化剂,用Hammett指示剂与紫外光谱相结合的方法测定固体杂多酸催化剂的酸度,发现SiW12/NaY酸性最强。单因子实验研究了制备条件对SiW12/NaY固体酸催化剂酸活性的影响,正交试验探讨了影响SiW12/NaY固载杂多酸活性四个因素的大小顺序为:烧结时间>烧结功率>浸泡浓度>浸泡时间,催化剂制备的优化条件为:硅钨酸水溶液浓度0.10 mol/L,浸泡时间30 h,微波功率750 W,烧结时间40 min,制得的催化剂酸度最高。应用0.050 g SiW12/NaY固载硅钨酸催化剂降解150 mg/L,pH值为3的十二烷基苯磺酸钠(LAS)溶液60 min,LAS降解率由76%提高到94.5%。固载硅钨酸催化剂对LAS的降解率明显提高。     

椰子油乙氧基化物与阴离子表面活性剂协同效应研究

摘要：对椰子油乙氧基化物-30EO（COE-30）与直链烷基苯磺酸（LAS）、脂肪醇聚氧乙烯醚硫酸钠（AES-2）及脂肪醇聚氧乙烯醚羧酸钠（AEC-5）复配的二元体系进行研究,运用非理想溶液理论计算混合胶束和混合吸附层的组成及二者在混合胶束和混合吸附层中协同作用参数。结果表明,复配体系在混合胶束和混合吸附层显示出较强的协同作用,混合胶束中作用参数|βm|= 2~6,混合吸附层中作用参数|βσ|= 2~6。三个复配体系在形成胶束能力和降低表面张力效率方面存在协同增效作用,同时COE-30/AES-2和COE-30/AEC-5体系在降低表面张力能力方面也存在协同增效作用。