Publication Date

Spring 2023

Document Type

Capstone Project

Degree Name

Master of Science

Department

Analytical Chemistry

First Advisor

John R. Sowa, Ph.D.

Second Advisor

K. G. Sanjaya Ranmohotti, Ph.D.

Third Advisor

Derick D. Jones, Jr. Ph.D.

Abstract

Polyol-induced extraction (PIE) is applied to the extraction of cashew nutshell liquid (CNSL) from cashew nutshells using glycerol as a mass-separating agent. In this process, a 1:1 mixture of acetonitrile (ACN) and water (H2O) exists as a completely miscible homogeneous phase. Cashew nutshells are soaked in this mixture at room temperature. After soaking the nutshells in acetonitrile/water, a polyol, glycerol, is added to the mixture, and a phase separation is observed. Upon cooling to –20 °C, the phase separation increases with an acetonitrile-rich top layer containing analytes that are soluble in acetonitrile. Initially, the PIE process was studied with pure caffeine as a test molecule. Using a 1:1 mixture of acetonitrile and water, 20 % (w/v) of glycerol and cooling to -21 °C, an acetonitrile-rich upper layer formed in 30 % of the total volume. The partition coefficient for caffeine (KPC) was 1.0. Extraction of 2.06 g of cashew nutshells produced 0.33 g of CNSL in 16.0 % yield. By comparison, extraction of 2.05 g of cashew nutshells with cyclohexane produced 0.38 g of CNSL in 18.5 % yield. While extraction of 12.01 g of cashew nutshells by the Soxhlet method using acetonitrile as a solvent produced 2.45 g CNSL in 20.4 % yield. The extracts were analyzed by HPLC, GC-MS, and NMR instruments. The HPLC peak area analysis revealed that the saturated form of anacardic acid was only a minor component (about 2 %). Moreover, 1H NMR analysis indicates that the major component of the extract is a decarboxylated derivate of anacardic acid (Figure 1) which is cardanol (Figure 2). This decarboxylation reaction occurred in the GC-MS due to the loss of the carboxylic acid group from the anacardic acid.

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