Purification of carboxymethylated fatty alcohol derivates using ion exchange resins

Abstract

During synthesis of the surfactants, several byproducts are formed that impact the physico-chemical properties as well as the quality of the product. Removal of these impurities is hence of vital interest, but the purification has remained chemically challenging. In this work, the ion exchange resin type I strong base anion polymeric catalyst was used to remove impurities such as remaining raw material and byproducts from different ether carboxylic acid surfactants. The efficiency of this preparative purification method was determined through analysis of the product composition using different analytical techniques such as titrimetric acid and saponification value determination, gas chromatography, Infrared (IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The results showed the high efficiency of the purification of the ether carboxylic acid surfactants using ion exchange resin. For all purified samples, the amount of byproducts such as esters and remaining raw material was found significantly reduced. Pure anionic surfactants (>90%) were obtained. Its ease of use and high efficiency render the method suitable for carboxymethylated surfactants. Additional investigations on industrial scales and further surfactant purification are yet to be analyzed.