Renewable Surfactants from Cashew Nut Shell Liquid: Synthesis, Characterization and Application.

This study presented two approaches to synthesize bio-surfactants using cashew nut shell liquid (CNSL), an abundant natural resource. The different preparation conditions were investigated and optimized to obtain the surfactant products of maximum weight and desired characteristics. The anionic sodium anacardate surfactant was recommended to be synthesized by carrying out the saponification reaction between CNSL and NaOH in a weight ratio of 1 : 2 at 85°C for 1 h. Meanwhile, the amphoteric triethanolamine anacardate surfactant was prepared using the neutralization reaction between CNSL and triethanolamine in a weight ratio of 1 : 1 at 70oC in 3 h. All the surfactant products were examined by Fourier transform infrared spectroscopy to confirm their chemical structure. In addition, characteristic properties of the surfactants including solubility, emulsifying ability and stability, foaming ability and stability, surface tension, and skin irritation were also explored. Both the sodium anacardate and triethanolamine anacardate demonstrated comparable foaming capacity and surface tension with commercial surfactants. In an attempt, sodium anacardate was utilized to make industrial soap and shoe polish of good sensory quality. [ABSTRACT FROM AUTHOR]