EPOXIDATION OF PALM OIL CATALYZED BY VANADYL(IV)- PHENOXYIMINES WITH TERTIARY BUTYL HYDROPEROXIDE
Indonesia is the largest producer of palm oil. Palm oil has numerous applications due to its versatility. Epoxidized palm oil (EPO) is a valuable derivative with a higher economic value compared to palm oil (PO). EPO can be used directly as a plasticizer or as an intermediate in the synthesis...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/82760 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Indonesia is the largest producer of palm oil. Palm oil has numerous applications
due to its versatility. Epoxidized palm oil (EPO) is a valuable derivative with a
higher economic value compared to palm oil (PO). EPO can be used directly as a
plasticizer or as an intermediate in the synthesis of lubricants, adhesives, and
coating materials. Additionally, EPO can replace phthalates, which are restricted
in the United States and Europe due to their carcinogenic properties. EPO is
produced by oxidizing the carbon-carbon double bonds in the triglyceride chain
of palm oil to form an oxiran ring. The conventional method of EPO synthesis
involves the use of hydrogen peroxide and mineral acid, which is an exothermic
process resulting in low selectivity and corrosive effects on the reactor. The
epoxidation reaction can be catalyzed by transition metals using oxygen sources
such as tertiary butyl hydroperoxide (TBHP). The complex of MoO2(acac)2 was
reported to produce 54% epoxide at 110 °C for 2 h. However the reactions used
toluene as solvent, which requires separation of product after the reaction is
complete. Recent studies show the activity of vanadium Schiff base in the
epoxidation reaction. Phenoximine is one of the Schiff base ligands. To the best of
our knowledge, there is no report of palm oil epoxidation using vanadyl(IV)
phenoxyimine thus far. This study evaluates the activity of vanadyl(IV)
phenoxyimines in the palm oil epoxidation in the absence of solvents and mineral
acids. The electronic character of vanadium is modified by a nitro moiety in the
phenoxyimine ligand. The synthesis of the vanadium(IV)-phenoximine complex is
done by reacting vanadium sulfate with the phenoximine ligand. The results show
that the solid complex is green. The synthesized complexes were characterized
using P-XRD, MS, FTIR, and MSB. The vanadium(IV)-phenoxyimine complex is
used for the epoxidation of palm oil with TBHP as the oxidant. The product of
epoxidation is analyzed using 1H-NMR. The catalytic activity test shows that the
complex VO(FI-1c)2 produces the highest yield of epoxide, 57%, compared to
VO(FI-1a)2 and VO(FI-1b)2, which are 54% and 16%, respectively, under
conditions of 70 °C, 3 meq TBHP, 0.3 mol% catalyst, and 7 h. The optimization of
reaction parameters for the complex VO(FI-1c)2 shows that 68% epoxide (TOF
76 h?1) can be produced when the reaction at 80 °C, 7 h, 0.1 mol% catalyst, and 3
meq TBHP. The kinetic study at 60, 70, and 80 °C shows that the vanadium(IV)
phenoxymine catalyzed epoxidation is pseudo second-order. The values of activation energy is 65 kJ/mol while enthalpy, entropy, and Gibbs free energy of
activation at 80 °C are 62 kJ/mol, ?83 J/mol K, and 92 kJ/mol, respectively. The
reaction without a catalyst does not produce epoxide, thus the use of a catalyst is
necessary for epoxidation. The epoxidation reaction is proposed to occur through
the Sharpless mechanism. The complex VO(FI-1c)2 produces the highest yield of
epoxide which may indicate that the key step in the epoxidation reaction is the
single electron transfer step. |
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