STUDY OF RHODIUM BASE CATALYZED HYDROFORMYLATION OF STYRENE BY AB INITIO COMPUTATIONAL APROACH
Study on the mechanism of styrene hydroformylation reactions have been carried out. Several previous studies have shown that rhodium-complexes-based catalyzed of styrene hydroformylation produce branched aldehydes as the main product. However, fundamental questions about regioselectivity in this rea...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/38213 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Study on the mechanism of styrene hydroformylation reactions have been carried out. Several previous studies have shown that rhodium-complexes-based catalyzed of styrene hydroformylation produce branched aldehydes as the main product. However, fundamental questions about regioselectivity in this reaction is still not fully answered. This is because the structure of the intermediate compounds never succeed to characterize kinetically and thermodynamically. This encourage researchers to perform computational studies on the mechanism of the hydroformylation reaction. Calculations based on quantum theory allow researchers to conduct studies on various theoretical structures of intermediates and even transition states involved in these reactions. The purpose of this study is to determine the path ways of styrene hydroformylation reaction mechanism with rhodium-based catalyst that leads to the branched aldehyde product. This study used ab initio computational methods at the level of theory and basis set HF/3-21G. Calculation software that used is NWChem 6.0 and Gaussian 09. While molecular visualization software using Gaussview, Jmol, and Avogadro. The results showed that branched products become the preferred product energetically. This is evidenced by the calculation results of the value of potential energy is -103.8779 kJ/mol for the branched product. This result is relatively lower than the energy of the linear product, -98.4773 kJ/mol. Various structural intermediates has also been successfully determined, including ?-complex, that its transition state was not found in previous studies. ?-complex intermediate has a relatively high energy that is equal to 37.2164 kJ/mol. Transition state energy calculation predicts that the rate determinant step in this reaction is the migration of alkyl ligand to perform the acyl complex, Rh(CO)2PPh3(acyl). This step showed the activation energy equal to 54.31 kJ/mol. |
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