EFFECT OF FUNCTIONAL GROUPS ON VANADYL DIKETONATE FOR EPOXIDATION REACTION

• Main Author: Octania Sinaga, Duwika
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75558
• Institution: Institut Teknologi Bandung

The epoxidation reaction is one of the most widely used reactions to form epoxide compounds as intermediate in the synthesis of hydroxy groups. A double bond (C=C) is formed into an epoxide using a catalyst and an oxidant in an epoxidation reaction. One of the catalysts that is commonly used for epoxidation is vanadium metal-based catalyst. In previous studies, 4 types of vanadium(IV) catalyst complexes have been synthesized with several types of ligands such as acetylacetone (acac), benzoylacetone (bzac), 1,3-diphenyl-1,3-propanadion (bzbz), and 4,4,4-trifloro-1-phenyl-1,3-butanadione (bztf). Based on the epoxidation results of palm oil using the four vanadil diketonate complexes at certain compositions, it was observed that the catalytic activity and the epoxide yield were not much different. Computational studies were needed to determine whether the epoxidation activity is not significantly affected by the type of ligand in the vanadil complex. Vanadil with acac ligand, VO(acac)2 and vanadil with bzbz ligand, VO(bzbz)2 were analyzed in this study. Computational studies were carried out using the DFT (Density Functional Theory) method with the B3LYP functional and 6-31g(d,p) basis set to determine the ESP (Electrostatic Potential) and the GFN2-xTB method to determine the Gibbs free energy of epoxidation reaction. Based on computational studies, the VO(bzbz)2 complex has a higher ESP charge than the VO(acac)2 complex so that the Lewis acidity of the VO(bzbz)2 complex is higher than the VO(acac)2 complex. More epoxide products estimated will be produced in epoxidation with VO(bzbz)2 catalyst than with VO(acac)2 complexes. It is reflected in the products of methyl oleate and methyl ricinoleate epoxidation with tertiary butyl hydroperoxide (TBHP) oxidizer using VO(bzbz)2 catalyst which is greater than using VO(acac)2 catalyst. It also confirmed by the results of the computational study in the rate- determining step of the epoxidation mechanism using GFN2-xTB method, both energetically and kinetically, the epoxidation of methyl oleate with VO(bzbz)2 catalyst was more stable than VO(acac)2 catalyst because the Gibbs free energy using VO(bzbz)2 is lower than using VO(acac)2.