Synthesis of porous Cu-BTC with ultrasonic treatment: Effects of ultrasonic power and solvent condition

• Investigation of the effect of different solvents with and without base addition during ultrasonic synthesis of Cu-BTC.
• Irradiation time and ultrasonic power effects on process yield and determination of optimum synthetic condition.
• Excellent Cu-BTC crystal yield of 86% was observed from water/ethanol/DMF solvent condition.
• Experimentation with water/DMF solvent condition and attainment of Cu-BTC crystal with very high surface area of 1430 m2/g.

Cu-BTC (BTC = 1,3,5-benzenetricarboxylate) metal organic framework (MOF) was synthesized using different solvent conditions with ultrasonic treatment. Solvent mixtures of water/N,N-dimethylformamide (DMF), water/ethanol were used for the reactions with or without a variety of bases under 20 kHz ultrasonically treated conditions. Prepared crystals were purified through 30 min of sonication to remove unreacted chemicals. Treatment time and ultrasonic power effects were compared to get optimum synthetic condition. The characterization of MOF powders was performed by scanning electron microscopy, X-ray powder diffraction, infrared-spectroscopy, thermo-gravimetric analysis and specific surface determination using the BET method. Isolated crystal yields varied with different solvent and applied ultrasonic power conditions. A high isolated crystal yield of 86% was obtained from water/ethanol/DMF solvent system after 120 min of ultrasonic treatment at 40% power of 750 W. Different solvent conditions led to the formation of Cu-BTC with different surface area, and an extremely high surface area of 1430 m2/g was obtained from the crystals taken with the solvent condition of water:DMF = 70:30.