Synthesis and application of vHP-SPS-Cat catalyst

A (virtual homogeneous phase) sulfonated polystyrene catalyst (vHP-SPS-Cat) was prepared from the radial chain polystyrene resin (PS-g-LPS). The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis and optical microscope. Its catalyst activity for esterification of n-butanol and acetic acid was measured. Experimental results showed that the catalyst had a higher catalytic activity, owing to its quasi homogeneous catalysis, than conventional homogeneous catalysts such as sulfuric acid and two other heterogeneous sulfonic acid resins (macroporous polystyrene resin and gel-type polystyrene resin). The maximum yield was abtained when the amount of catalyst was 2.4 g/mol (according to n-butanol), molar ratio of acetic acid to n-butanol was 1.3:1, and reaction time was 1h. Moreover, the catalyst could be used more than 10 times under the high temperature of 125°C without significant loss of activity.