Preparation of polyol esters using acidic heterogeneous catalysts

Abstract

The sulfonic functionalized SBA-15, SBA-15-PrSO3H, was prepared by hydrothermal method and post-grafting synthesis. The synthesized materials were characterized by X-ray powder diffraction, nitrogen sorption analysis and scanning electron microscopy. The synthesized catalyst was studied its performance comparing to several heterogeneous catalysts in the esterification of neopentyl glycol and octanoic acid which was firstly optimized the suitable condition using Amberlyst-15 as a catalyst. The synthesized material performed the best efficient catalyst which could reduce reaction time from 4 to 2 hours. Thus, the optimal condition performed at 80 oC for 2 hours with stirring speed 200 rpm using 3 wt. % of SBA-15-PrSO3H based on total reaction weight in stainless steel batch reactor which gave high total ester yield as 74.1% and 76.9% of NPG dioctanoate ester selectivity in order to using the octanoic acid to neopentyl glycol mole ratio as 2. Moreover, the reaction mixtures exhibited highest NPG dioctanoate ester selectivity as 89.1% with 78.1% of total ester yield in case the octanoic acid to neopentyl glycol mole ratio increased to 4. Additionally, the esterification with difference molecular size of monocarboxylic acid and alcohol type significantly affected to the total ester yield and diester selectivity due to the difference requirement of energy. For reusability test, the SBA-15-PrSO3H was used two times to examine its reusability. It was indicated that the hexane washed catalyst obtained the best performance in reusability experiment. Moreover, the catalyst regeneration could improve its reactivity