Application of Taguchi Optimization Method in Improving the Selectivity of Dihydroxystearic Acid

Dihydroxystearic acid (DHSA) is perceived to be of significant value to various types of industries, especially the oleochemical industry. It is produced by reacting palm-based crude oleic acid (OA) with formic acid and hydrogen peroxide through the in situ epoxidation-dihydroxylation, a multistep reaction process. Optimization of the reaction’s operating conditions with respect to the selectivity of DHSA was conducted via the Taguchi method of optimization. The selectivity of DHSA was determined based on gas chromatography (GC) analysis. The signal-to-noise (S/N) ratio analysis procedure in Taguchi method revealed that the optimum operating conditions for the production of crude DHSA with respect to its selectivity were found to be: catalyst (sulphuric acid) loading at 0.5 gm, formic acid-to-oleic acid unsaturation mole ratio of 1:1, hydrogen peroxide-to-oleic acid unsaturation mole ratio of 0.75:1 and reaction temperature: 85°C. ANOVA tested at 90% confidence level revealed that reaction temperature and catalyst loading highly affect the selectivity of DHSA. The selectivity of DHSA was improved to 97.2% by applying the optimum operating conditions as obtained by Taguchi method.