Preparation of Novel Solid Acid Based on Hypercrosslinked Polymer and the Catalytic Activities in the Synthesis of Ethyl Levuminate and Biodiesel

Abstract

The novel solid acid based on hypercrosslinked polymer (HCPs–SO₃H) was synthesized via the direct copolycondensation of 4,4'-bis(chloromethyl)-1,1'-biphenyl (BCMBP) and naphthalene and sulfonation using chlorosulfonic acid. The polymer structure could be adjusted by naphthalene. The extremely high surface area of 1044 m²/g and mesoporous texture facilitate mass transfer of reagents, and special rigid aromatic ring framework ensured the expressed hydrophobicity of the surface. The plentiful aromatic rings provided sufficient sulfonation sites, and after sulfonation acidity over 3.4 mmol/g. HCPs–SO₃H showed high activity for ethyl levulinate (EL) synthesis from furfuryl alcohol (FA) with maximum yield 90.5%. Also, the efficient procedure for biodiesel synthesis from waste oil (WO) was developed using the HCPs–SO₃H. Both the free fatty acids (FFAs) and glycerides were conversed to methyl esters of fatty acids (biodiesel) with total yield over 99%. Therefore, the high surface area, high acidity and special rigid aromatic ring framework were the key features for the high activities of novel HCPs–SO₃H in organic synthesis.