Synthesis of porous polymer-based solid acid and its catalytic activities for biodiesel synthesis from waste oil and tetrahydropyranylation of alcohols

The novel porous polymer-based solid acid was synthesized via the polycondensation of 1,4-dichloroxylene (DCX) and following sulfonation using chlorosulfonic acid. The polymer structure could be adjusted by introducing naphthalene. The extremely high surface area of 816 m 2 /g and organic framework provided the mass transfer efficiency and hydrophobic surface. The abundant aromatic rings owned enough sulfonation sites, which resulted in high acidity over 2.7 mmol/g. The novel porous polymer-based solid acid showed high activities for the tetrahydropyranylation of alcohols with the yield over 90% in 5 min at room temperature using 1 wt.% catalyst. The novel solid acid could be recycled for 13 times. The efficient procedure for biodiesel synthesis from waste oil on mild condition was also developed using the solid acid. Both the free fatty acids and glycerides were transformed to the biodiesel products with the yield over 99%. The high surface area, high acidity and the organic framework were the key factors for the high activities, which hold great potential in green chemistry.