Valorization of Madagascar’s CNSL via the synthesis of one advanced intermediate (3-Pentadecylcyclohexanone)

A comprehensive review on sustainable surfactants from CNSL: chemistry, key applications and research perspectives

Surfactants, a group of amphiphilic molecules (i.e. with hydrophobic(water insoluble) as well as hydrophilic(water soluble) properties) can modulate interfacial tension. Currently, the majority of surfactants depend on petrochemical feedstocks (such as oil and gas). However, deployment of these petrochemical surfactants produces high toxicity and also has poor biodegradability which can cause more environmental issues. To address these concerns, the current research is moving toward natural resources to produce sustainable surfactants. Among the available natural resources, Cashew Nut Shell Liquid (CNSL) is the preferred choice for industrial scenarios to meet their goals of sustainability. CNSL is an oil extracted from non-edible cashew nut shells, which doesn't affect the food supply chain. The unique structural properties and diverse range of use cases of CNSL are key to developing eco-friendly surfactants that replace petro-based surfactants. Against this backdrop, this article discusses various state-of-the-art developments in key cardanol-based surfactants such as anionic, cationic, non-ionic, and zwitterionic. In addition to this, the efficiency and characteristics of these surfactants are also analyzed and compared with those of the synthetic surfactants (petro-based). Furthermore, the present paper also focuses on various market aspects and different applications in various industries. Finally, this article describes various future research perspectives including Artificial Intelligence technology which, of late, is having a huge impact on society.

CNSL, a Promising Building Blocks for Sustainable Molecular Design of Surfactants: A Critical Review

Surfactants are crystallizing a certain focus for consumer interest, and their market is still expected to grow by 4 to 5% each year. Most of the time these surfactants are of petroleum origin and are not often biodegradable. Cashew Nut Shell Liquid (CNSL) is a promising non-edible renewable resource, directly extracted from the shell of the cashew nut. The interesting structure of CNSL and its components (cardanol, anacardic acid and cardol) lead to the synthesis of biobased surfactants. Indeed, non-ionic, anionic, cationic and zwitterionic surfactants based on CNSL have been reported in the literature. Even now, CNSL is absent or barely mentioned in specialized review or chapters talking about synthetic biobased surfactants. Thus, this review focuses on CNSL as a building block for the synthesis of surfactants. In the first part, it describes and criticizes the synthesis of molecules and in the second part, it compares the efficiency and the properties (CMC, surface tension, kraft temperature, biodegradability) of the obtained products with each other and with commercial ones.

Synthesis of novel chemicals from cardanol as a product of cashew nutshell processing

The conversion of the worldwide chemical production from fossil to sustainable resources is currently one of the most urgent tasks for the chemical industry. Based on this approach cardanol, a mixture of phenols with C15-chains as substituents is produced in some countries of the tropical zone from the processing of cashew nutshells. The paper reports the specific transformation of the aromatic moiety in this cheap material, and thus, the development of a novel route to potential useful green bifunctional chemicals in gram scale. Accordingly, cardanol was converted successfully in three steps into hexane-1,6-diols. The evaluation of appropriate synthesis methods and suitable conditions for each of these reaction steps is presented as an essential topic of these investigations. The target compounds synthesized in the reaction sequence are potential building blocks for future biomass-based chemicals and monomers for green polymeric materials, surfactants, and lubricants.