فهرست نشریات علمی دسترسی آزاد ایران

Catalytic transfer hydrogenation (CTH) is a vital method for selective reduction reactions in organic synthesis, involving the transfer of hydrogen from a donor molecule to a substrate in the presence of a catalyst. This study aims to optimize the catalytic transfer hydrogenation process for sustainable synthesis by investigating the hydrogenation of cinnamic acid using PdCl₂ and Pd(acac)₂ catalysts under various reaction conditions. We systematically studied the impact of different reaction parameters, including hydrogen donors, solvents, bases, and catalyst loading, emphasizing the importance of each factor for achieving optimal catalytic performance. Notably, water emerged as the most effective solvent for PdCl₂ at 90 °C with 2 mol% catalyst loading, achieving a 100% yield of phenylpropanoic acid. This outcome aligns with the principles of green chemistry, as water—an environmentally friendly solvent—reduces the need for toxic or hazardous alternatives. The presence of a base is essential for achieving maximum efficiency, with KOH resulting in a 99% yield. In addition, PdCl₂ at 2% catalyst loading proved highly efficient, achieving excellent results under these conditions. In the case of Pd(acac)₂-catalyzed 4'-phenyl(ethynyl)acetophenone reduction, ultrasonication significantly accelerated the reaction, achieving 100% conversion in just 1 hour at 60 °C, compared to 7–24 hours required with conventional heating. Ultrasonication not only enhanced reaction rates, but also improved selectivity, providing an energy-efficient alternative to traditional heating methods. These findings offer valuable insights into optimizing catalytic transfer hydrogenation, emphasizing the critical roles of catalyst, solvent, base, heating method, and hydrogen donor in achieving efficient, selective, and sustainable reductions.