Solvent-Free Synthesis of HKUST‑1 with Abundant Defect Sites and Its Catalytic Performance in the Esterification Reaction of Oleic Acid

HKUST-1 has received increasing attention because of its
potential applications in many fields, such as heterogeneous catalysis,
sensors, gas storage, and separation. Herein, we report that HKUST-1 can
be facilely prepared by heating a ground mixture of copper nitrate
trihydrate and 1,3,5-benzenetricarboxylic acid in an autoclave at 80 °C for
10 h. The data from nitrogen sorption show that the obtained material,
named HKUST-1-free, possesses a high BET specific surface area of 1671
m2/g and a pore volume of 0.8 cm3/g. The results from acid−base titration
indicate that the number of defect sites in HKUST-1-free is more than that
in HKUST-1-solvent prepared by the solvothermal method. As a
heterogeneous catalyst, HKUST-1-free gave a high yield (91%) of methyl
oleate in the esterification reaction of oleic acid with methanol at room
temperature compared to HKUST-1-solvent (70%). Additionally, it is
proven that HKUST-1-free is a heterogeneous catalyst and can be reused.