Search

Linear alkylbenzene sulfonic acid (ABSA) is used to produce industrial and domestic synthetic detergents and is obtained via a multistage technology. Unsteady-state mathematical model considering mass transfer was developed for linear alkylbenzenes (LAB) sulfonation technological stage. With use of the developed model we studied how the modes in the film sulfonation reactor influence the product quality and yield. The varied parameters were SO3 concentration in the air flow, process temperature and SO3/LAB molar ratio. It was found that the air flow rate of 10,000 m3/h, temperature 30 °C, pressure 170 kPa are the optimal process conditions. Under these conditions, the degree of the feedstock conversion is close to 1, and the share of the target product is about 98.4 wt.%.

A possibility of using an industrially produced anionic surfactant, alkylbenzenesulfonic acid, for the precipitation and flotation extraction of neodymium(III), erbium(III), and thulium(III) ions is investigated. The influence of the concentration and ratio of the reacting components and the concentrations of sulfuric acid and sodium hydroxide on the degree of precipitation of metal ions is considered. The composition of the resulting compounds is established and their conditional solubility products are calculated. Conditions for the flotation of metal ions with alkylbenzenesulfonic acid are optimized. [ABSTRACT FROM AUTHOR]

The relevance. Lack of experimental data that allow developing a scientifically based method for calculating and designing film-type reactors, which are also used to produce alkylbenzenesulfonic acids. These acids, in their turn, are currently the main components of synthetic detergents. The issue of increasing reactor equipment efficiency can be most effectively solved using mathematical models built on a physical and chemical basis. The aim. Development of a mathematical model of alkylbenzenes sulfonation, taking into account a substance mass transfer from a gas phase to a liquid phase. Software implementation of the developed model, as well as the use of the developed mathematical model for studying the influence of the process parameters on its efficiency. Object. Alkylbenzenes sulfonation with sulfuric anhydride in a multitube film reactor. Methods. Mathematical modeling is used to perform all computational operations, a modern high-level general-purpose programming language with automatic memory management is used. The quantum-chemical methods for determining thermodynamic parameters of chemical reactions were used. Results. The paper considers the principles of constructing a mathematical model of sulfonation. The authors have developed the calculation program in the Python programming language and assessed the accuracy of description of a real process and the influence of the system technological parameters on a product yield and quality, taking into account a substance interfacial transfer. The system of practical recommendations for improving the alkylbenzenes sulfonation resource efficiency was developed. The mathematical model adequately describes the process. The calculated data are compared with the real data from the operating unit for alkylbenzenes sulfonation with sulfuric anhydride.

Within the framework of the work, a mathematical model of the process of sulfonation of linear alkylbenzenes with SO3, which takes place in a multitube film reactor, is described. The causes and regularities of changes in the most important indicator of the quality of alkylbenzenesulfonic acid - its color index - are described. Using a mathematical model, it was found that the content of light aromatic compounds in the sulfonation feedstock worsens the color of ABS and leads to a reduction in the duration of the interwashing cycle. [ABSTRACT FROM AUTHOR]

In this work, we analyze the influence of the linear alkylbenzenes consumption of in a multitube film sulfonation reactor on the formation of viscous by-products, tetralins and sulfones, using the method of mathematical modeling. It was found that an increase in the consumption of raw materials from 3500 to 4500 kg/hour at a constant molar ratio of SO3/LAB equal to 1.08 makes it possible to achieve a decrease in the contact time of linear alkylbenzene with a sulfonating agent from 30.1 to 25.4 seconds and an increase in the duration of inter-flushing cycles due to a decrease in the viscosity of the organic liquid film and the normalization of the hydrodynamic regime of the flow of raw materials. It was also determined that the duration of inter-flushing cycles is influenced by the content of light aromatic hydrocarbons in the sulphonated raw material. An increase in the content of aromatic hydrocarbons leads to a decrease in the duration of the inter-flush cycles. This is due to the fact that light aromatic hydrocarbons are the source of the formation of viscous by-products - tetralins, which have a negative effect on the hydrodynamic regime of the liquid film flow. Calculations using a mathematical model showed that with an aromatic hydrocarbon content in the feed of 2 %wt. the duration of the inter-washing cycle at a standard flow rate of 3500 kg/hour is 15 days, and at 6 % wt. - 10 days. At the same time, an increase in consumption up to 4500 kg/hour makes it possible to achieve a cycle time at 2% wt. up to 17 days, and at 6% wt. up to 16 days. [ABSTRACT FROM AUTHOR]

Acidic lyotropic liquid crystals (LLCs) have an advantage in constructing continuous proton conduction pathways owing to the well-defined structures, but the contribution of LLC to proton conductivity is hard to determine for the water-dependent nature of LLC. An aqueous 4-(1-ethyldecyl) benzenesulfonic acid solution, exhibiting a lamellar LLC phase at low hydration levels and becoming a micellar solution at high hydration levels, is employed to investigate structure-dependent proton conductivity. Electrochemical impedance spectrum (EIS) characterization reveals that the proton conductivity reaches a maximum of 173 mS cm−1 in the LLC phase. Owing to the self-assembling, the degree of dissociation of -SO3H tends to stabilize at 0.26 with increasing hydration levels. An integrated rate constant Ki is derived to evaluate the effect of self-assembly on proton conductivity, which reaches 1.90 × 107 mS cm5 mol−2 in the LLC but decreases to 1.23 × 107 mS cm5 mol−2 in the micellar solution. The single fuel cell fabricated from the LLC supported membrane exhibits a peak power density of 23.7 mW cm−2, confirming the enhanced proton conductivity under actual working conditions. The results quantitatively unveil the effect of aqueous self-assembly on proton conduction and offer a guide for achieving high conductivities in hydrated electrolytes with well-defined architectures. [ABSTRACT FROM AUTHOR]