A novel sublimable organic salt: Synthesis, characterization, thermal behavior, and catalytic activity for the synthesis of arylidene, heteroarylidene, and alkylidene malonates

• Main Authors: Johari, Suzaimi, Zaharani, Lia, Gorjian, Hayedeh, Johan, Mohd Rafie, Khaligh, Nader Ghaffari
• Format: Article
• Published: Springer Verlag 2022
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/33772/

A novel sublimable organic salt was synthesized, and its chemical structure was characterized by FTIR, 1D NMR, 2D NMR, and elemental analysis. In addition, the thermal phase transitions and thermal stability of new organic salt were investigated. The DSC and TGA results showed that the organic salt could convert into constituent molecules at < 145 degrees C before decomposition temperature (T-dec. similar to 200 degrees C) under atmospheric pressure without forming the liquid phase. Then, it was recondensed to regenerate the initial organic salt in the cool part of the vial. Therefore, it can be a promising organic salt towards the regeneration of spent catalyst from synthesis processes when the reaction mixture contains poorly volatile components and includes its use in gas-phase procedures. Also, the catalytic efficiency of new organic salt was investigated in the Knoevenagel condensation reaction. A variety of substituted arylidene and alkylidene malonates were isolated in 78-95% yield within six hours.(sic) Under the optimized reaction conditions, the current catalytic procedure exhibited superiority compared to the mixed piperazine/acetic acid, piperidine/acetic acid, and piperidinium acetate. There were no significant changes in the new organic salt chemical structure and catalytic activity even after the 5th run. This work revealed the importance of the existence of simultaneous hydrogen bond acceptor/donor groups in our environmentally friendly catalyst to promote the Knoevenagel condensation reaction without the use of metal-containing catalysts.