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Synthesis and characterization of different types of epoxide-based Mannich polyols from low-cost cashew nut shell liquid


Cashew nut shell liquid (CNSL) is a natural aromatic organic oil consisting of phenolic compounds with interesting structures. Extraction of CNSL was performed in a Soxhlet apparatus. The major (90 %) component of CNSL is anacardic acid, which is easily decarboxylated to cardanol (10 %) by use of conventional methods. In this paper we describe a three-step synthesis of Mannich polyols for rigid foams. The first step is synthesis of N-(2-hydroxyethyl)-1,3-oxazolidine (the Mannich precursor) by condensation of paraformaldehyde and diethanolamine. The second step involves synthesis of the Mannich base phenolic ring of cardanol by reaction with N-(2-hydroxyethyl)-1,3-oxazolidine. The third step is alkoxylation. The synthesized polyols were characterized by FTIR and 1H NMR spectroscopy and thin-layer chromatography.

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The author wish to thank the Department of Applied Chemistry, SVNIT, Surat, for providing laboratory facilities, and Gujarat Cashew Industrial (Kutch, Gujarat, India), for providing the initial product. Analytical facilities provided by the Centre of Excellence, Vapi, Gujarat, India, and Punjab University, Chandigarh, India, are gratefully acknowledged.

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Correspondence to Bharatkumar Z. Dholakiya.

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Gandhi, T.S., Patel, M.R. & Dholakiya, B.Z. Synthesis and characterization of different types of epoxide-based Mannich polyols from low-cost cashew nut shell liquid. Res Chem Intermed 40, 1223–1232 (2014).

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  • Cashew nut shell liquid
  • Mannich precursor
  • Mannich base
  • Mannich polyols