Short Chain Alkyl Sulfonates
Short chain alkyl sulfonates are surfactants widely used in a variety of industrial, institutional, and domestic applications. These alkyl sulfonates have a variety of features which make them beneficial in the chemical industry, including their general low toxicity, low environmental impact, and ease of biodegradability. Alkyl sulfonates have become a preferred surfactant in the past few decades due to increasing environmental concerns and chemists looking to replace more toxic surfactants such as NPEs (Nonyl Phenol Ethoxylates) with less toxic surfactants that have greater biodegradability.
The majority of short chain alkyl sulfonates are composed of a sulfonate group, typically a combination of sulfuric and sulfonic acids, attached to an alkyl chain which can be derived from both petrochemicals and bio-renewable resources. The length of the alkyl chain can vary from two to five carbons, with a general preference towards shorter chain lengths as the number of carbons increases, so does the hydrophobicity. For example, sodium dodecyl sulfonate or sodium lauryl sulfate (SLS) is one of the most commonly used alkyl sulfonates and contains twelve carbons. When applied to a hydrophobic industrial surface, the sodium dodecyl sulfonate molecules are more likely to adsorb to the surface than molecules with longer alkyl chains. This can lead to a lack of surface active molecules in the process, causing a decrease in the effectiveness of the surfactant.
In the industrial and institutional application, short chain alkyl sulfonates are mainly used as detergent additives and wetting agents. They are extensively used in a variety of industrial cleaning applications, such as floor cleaners, cloth cleaners and all purpose cleaners. These alkyl sulfonates also serve in wetting agents, which helps to suspend solids, disperse dirt and reduce surface tension in the system. Additionally, SLS is used as an anti-foaming agent and defoaming agent in industrial recovery processes and can also act as a dispersing agent to improve the manufacturing process of a variety of products, including paints, fertilizer and paper.
In the domestic application, short chain alkyl sulfonates are used extensively in a variety of product formulations for personal hygiene. For example, SLS is added to soaps as a foaming and cleansing agent and is often one of the main active ingredients in toothpastes that provide tartar and stain removal. Additionally, alkyl sulfonates are used as emulsifying and thickening agents in a variety of hair care products such as shampoos, conditioners and styling products.
Due to their general low toxicity and biodegradability, alkyl sulfonates have become the preferred surfactant for many applications and are suitable replacements for more toxic surfactants such as NPEs. Their superior wetting properties and low surface tension allow them to be more effective in cleaning, emulsifying, and suspending dirt and solid particles in the system. However, alkyl sulfonates do have some drawbacks, including their potential tendency to form gels over time and their potential to cause skin irritation to users with sensitive skin.
