Sulfonated surfactants manufacturing process

Because these materials are polymerized at acid pH to ensure incorporation of the acidic monomer, synthetic surfactants such as dode-cylbenzene sulfonic acid are used. Normally the pH of the system is raised with alkali at the end of reaction and the product is sold in the range of pH 6-10 depending on manufacturing process and grade. 

The primary application of these alcohols is the manufacture of anionic or nonionic surfactants for personal cleansing products, most of which end up in your wastewater treatment plants and rivers. Microorganisms don t chew up branch-chain surfactants as well as they do the straight ones. It used to be, for example that the surfactant based on the sodium salt of dodecyl benzene sulfonate, a 12-carbon branch chained anionic surfactant, was found to be slowing, down water treatment processes. Dodecyl alcohol as a raw material for these surfactants has been largely replaced by laurel alcohol, a 12-carbon straight-chain, linear alcohol. If you look at the bottle next time you shampoo your hair and rinse, you ll see sulfonates based on laurel alcohol listed, but none based on dodecyl. 

This step is essential in the manufacture of detergent active ingredients as it converts the sulfonic acids or sulfuric acid esters (products produced by processes I-M) into neutral surfactants. It is a potential source of some oil and grease, but occasional leaks and spills around the pump and valves are the only expected source of wastewater contamination. A process flow diagram is shown in Figure 14. 

Industrial surfactants find uses in almost every industry, from asphalt manufacturing to carpet fibers, from pulp and paper production to leather processing. Examples of the types of chemicals used as surfactants are fatty alcohol sulfates, alkanolamides, alkoxylates, sulfosuccinates, amines, quaternaries, phosphate esters, acid esters, blockcopolymers, betaines, imidazolines, alkyl sulfonates, etc. 

A relatively new process for siloxane manufacture is aqueous phase emulsion polymerization. Cyclosiloxanes such as D4 when mixed with water and alkylbenzenesulfonates as a surfactant, along with some free sulfonic acid, form an emulsion. When the mixture is heated to > 60 °C, ring opening of the cyclosiloxane takes place to give a, ty-dihydroxy oligosiloxanes, which undergo acid-catalyzed condensation to form long-chain siloxanes. 

A process to manufacture synthetic sulfonates was developed by Suntech Inc.. According to this process, caustic is used to neutralize the product, which minimizes the water usage during the process. Various companies such as Exxon and Shell have employed synthetic sulfonates for improving oil recovery. Several more expensive synthetic sulfonates also have been used as additives in the EOR processes. In such cases, a portion of the petroleum sulfonate prepared by sulfonation of gas/oil or crude oil is replaced with the synthetic sulfonates. It has been observed that the surfactant formulations containing mixed petroleum sulfonate and synthetic sulfonate have resulted in improved oil recovery. 

Fluorinated surfactants have been commercially available since the 1950s. The first available were perfluoroalkyl sulfonates (e.g., perfluorooctane sulfonate, CgFisSOs, PFOS) and perfluoroalkyl carboxylic acids (e.g., perfluorooctanoic acid, C7F15COOH, PFOA) manufactured using the electrochemical fluorination (ECF) process [10]. The unique properties (e.g., surface tension lowering in aqueous systems, high chemical and thermal stability) of these acids and their derivatives when used at low concentrations resulted in their widespread use in industrial processes and consumer uses [11-13]. The most common commercially produced perfluorinated surfactants are the perfluoroalkyl acids (PFAAs) ... 

At approximately the same time, a further process for the manufacture of anionic surfactants of the sulfonate type, namely the olefinesulfonates, became of interest. This process starts from a-olefines obtained by cracking of higher hydrocarbons. In this process, the olefine is reacted with SO3 for a short time in a thin-layer reactor. Alkenesulfonates and hydroxyalkanesulfonates are formed [18]. 

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