Orbitta Exports

Cashew nut shell liquid (CNSL) is obtained as a by-product in the production of cashew kernels. With an increasing production of raw cashew nuts, Brazil is also one of the leading world producers of CNSL1. Commercial CNSL is chiefly cardanol (1)2, a mixture of 3-alkylphenols (Figure 1) mainly produced by decarboxylation of anarcadic acid (2), the primary constituent of the original oil, after exposure to high temperatures of the industrial treatment of the raw nut. Anacardic acid (2), a mixture of 2-carboxy-3-alkylphenols, is the main component of the cold pressed or solvent extracted CNSL.

Chemicals derived from CNSL find demand in coating, photographic, polymer and surfactant markets. Our group has been developing a continuing effort on the synthetic transformation of the CNSL constituents into new substances with potential applications3. High molecular weight quaternary  nitrogen compounds are very stable, soluble in water, odourless and generally possess high bactericidal activity and act as surface active agents. These properties have made them particularly attractive as germicides, disinfectants and sanitizing agents, especially in food and dairy industries. The importance of long alkyl chain and quaternary nitrogen atom as fundamental units of structure for the activity of quaternary nitrogen compounds was established as early as 1930 by Domagk4. CNSL has been used previously to prepare quaternary ammonium salts, the aim of the investigation then was to prepare water soluble compounds to be tested as germicides5. We report an entirely different approach, in which the quaternary ammonium cation is placed at the end of the aliphatic chain, enhancing the lipophilic character of the resulting quaternary salts, which is a requirement for a substance to function as a phase transfer catalyst.

In this work, three new quaternary ammonium salts were synthesized from cardanol for use as phase transfer catalysts. Heterogeneous reactions were tested, such as oxidation with KMnO46, oxidation with NaClO7 and in Williamson ether synthesis8. The yields obtained are comparable to, and in some cases surpass, those obtained using the commercial product Aliquat.