Alkylaromatics in Detergents Manufacture: Modeling and Optimizing Linear Alkylbenzene Sulfonation

Abstract

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 SO 3 conversion up to 98%.Keywords Linear alkylbenzene sulfonic acid Á Sulfur trioxide Á Sulfones Á Mathematical model of sulfonation process J Surfact Deterg (2018) 21: 175-184.

Direct Alkylation of Benzene at Lower Temperatures in the Liquid Phase: Catalysis by Montmorillonites as Noble‐Metal‐Free Solid Acids

“…Alkylbenzenes are widely used as raw materials for the production of chemical compounds such as synthetic detergents, tunable organic solvents, and synthetic intermediates . Conventionally, alkylbenzenes are obtained by the Friedel‐Crafts reaction of alkyl halides and benzene (Scheme a).…”

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

“…However, developing an unsteady-state mathematical model of the sulfonation reactor allows us to predict the influence of various technological parameters and raw materials composition on the products yield and quality. (2) gas-liquid separation; (3) hydrogenation reactor to convert dienes to alkenes; (4) stripper; (5) alkylator; (6, 7, 8) fractionators; (9) sulfonation reactor; (10) block for sulfur combustion; (11) block of SO 2 to SO 3 oxidation; (12) ABSA neutralization (reproduced from (Dolganova et al, 2018) with permission from Wiley) The kinetic parameters of the model are dependent on the flow rate of the liquid film and the residence time of the reactants in the reactor. Therefore, to determine the average flow rate of a liquid film in a reactor, it is necessary to know the liquid film thickness.…”

“…Although the mechanism of LAB sulfonation has already been studied and mathematical models have been developed, the influence of the reactor construction on the process performance remains unexplored. However, the film uniformity and heat and mass‐transfer within the reactor undoubtedly influence the sulfonation efficiency (Dolganova et al, 2018). Reactors of various designs are used for LAB sulfonation; however, these do not always provide the required product quality.…”

“…The accumulation of viscous components leads to clogging of the reactor tubes, resulting in deviation from the film flow's optimal hydrodynamic operational mode, and therefore in reduction of the target product yield. When the concentration of highly viscous components (HVC) reaches a critical value, the reactor must be flushed with water to remove the viscous compounds (Dolganova et al, 2018).…”

“…According to the performed studies, the problem of a single‐tube film reactor of the glass‐in‐glass type is insufficient residence time between the reactor washings (Dolganova et al, 2018). This disadvantage has been addressed through of using the multi‐tube film apparatus.…”