Designing Efficient Metal Complex Catalysts for Acylation: A Comparative Study With Soluble and Insoluble Catalysts Systems

New soluble and insoluble Nb, Ta, Mo, and Sb complex catalysts have been developed using pyridine and polymersupported cross-linked (poly-4-vinyl pyridine) bead (PSCPVP), and characterized using FT-IR, SEM, EDAX, elemental analysis (CHN), and TGA. Their ability to catalyze the acylation of ethanol with acetic anhydride at 303K has been proven. Both soluble and insoluble chemicals have the same order of activity: MoCl5, TaCl5, NbCl5, and SbCl5. The insoluble catalyst outperformed in terms of activity by complex catalysts, although they have significant limitations in terms of solubility and recyclability and soluble homogeneous catalysts in terms of lowest cost and recyclability, whereas all soluble Py-MCl₅ catalysts exhibit better activity than insoluble PSCPVP-MCl5 catalysts according to the computed kobs values. Insoluble catalysts are preferable than soluble homogeneous catalysts in terms of recyclability, although all the soluble catalysts of Py-MCl₅, M= Nb, Ta, Mo, and Sb have exhibited better activity than insoluble PSCPVP-MCl₅ (k_obs= 6.51, 6.98, 7.48 & 1.73 x10³ min^-1) based on the computed k_obs values. For acylation process, it has been found that the soluble Py- NbCl5, Py-TaCl₅, Py-MoCl₅, and Py-SbCl₅ catalysts whereas 1.47, 1.63, 1.59, and 1.67 folds more active than PSCPVPNbCl5, PSCPVP-TaCl₅, PSCPVP-MoCl₅, and PSCPVP-SbCl₅ correspondingly