Natural Oil Polyol from High-Oleic Palm OilRReaction Kinetics and Monitoring Using Near-Infrared Spectroscopy

Natural oil polyols are widely usedbiobased monomers for the manufactureof polymers and resins. They are mainly produced via hydroxylation of epoxidized vegetable oils. This work studied thekinetics of hydroxylation of epoxidized high-oleic palm oil via oxirane ring cleavage with ethylene glycol (EG). Experimentswere performed at different temperatures (65-95 & DEG;C), hydroxyl-to-oxiranemol ratios (1.75-14), and catalyst loadings (H2SO4, 0.5-4% wt). The reaction was monitored by measuringthe hydroxyl value and oxirane oxygen content in samples using near-infraredabsorbance. Different power-law kinetic expressions were evaluated,and the lower average error (3.25%) resulted in first order with respectto epoxide, second order with respect to EG, and considering oligomersformation. The corresponding frequency factor and energy of activationfor hydroxylation were 3.58 x 10(4) and 51.9 kJ/mol,and those for oligomerization were 3.32 x 10(5) and67.2 kJ/mol, respectively. The obtained model is suitable for furtherprocess design and scale up.