Study on the synthesis and properties of cardanol sulfonate

Abstract

Abstract In this work, using the natural product cardanol and chlorosulfonic acid as the main raw materials, the anionic surfactant cardanol sulfonate (CDS) was synthesised and investigated for its surface properties and thermodynamic properties using surface tension, conductivity and fluorescence methods. In addition, the application properties of CDS, such as foaming and cleaning ability were investigated and compared with those of sodium dodecylbenzene sulfonate (SDBS). The structure of the surfactant was characterised by FTIR, 1H NMR and MS. The Krafft point of the surfactant was below 25 °C, indicating good water solubility. The CMC values were determined by surface tension, conductivity and micropolarity measurements. The obtained CMCs agreed well within the measuring accuracy. The CMC increased with increasing temperature. As a function of temperature, the following CMC values were obtained: 5.13 × 10−3 mol L−1 (25 °C), 5.63 × 10−3 mol L−1 (35 °C) and 5.77 × 10−3 mol L−1 (45 °C). The values of surface tensions at the respective CMCs were γ CMC = 44.47 mN m−1 (25 °C), 43.53 mN m−1 (35 °C), and 42.45 mN m−1 (45 °C). The application property results showed that the foaming capacity, foam stabilisation and cleaning ability of CDS and SDBS were similar to each other, indicating that CDS can be used as a raw material for commercial detergent production.