Throughout this thesis work, various catalysts were investigated with combinational
approach to develop highly active and selective novel catalysts for direct
epoxidation of propylene to PO using molecular oxygen.
The promoted and un-promoted silver (Ag), copper (Cu), ruthenium (Ru),
manganese (Mn) mono and multimetallic catalytic systems over different silica
supports were prepared via sol-gel method and incipient wetness method. In
addition to support effect, the effects of different promoters on the catalytic
performances of these catalyst candidates were investigated. The study showed
that commercial silica (c-SiO2) is the most effective support when compared to silica
(SiO2) and silica synthesized with templete (t-SiO2). Among bimetallic catalytic
systems containing Ag, Ru, Mn and Cu metals, c-SiO2 supported Cu-Ru catalyst was
determined as the most active catalytic system. In addition, the most effective
v
catalyst and promoter in the epoxidation reaction was determined as NaCI
promoted Cu-Ru catalyst supported over c-SiO2 with 35.98% selectivity& / 9.55%
conversion (3.44% yield) at 3000C and 0.5 feed gas ratio (C3H6/O2)..
In the study, the selected catalysts showed low and high PO productivity were also
investigated by characterization techniques such as XRD, XPS, BET and FTIR.It was
inferred from characterization tests that bimetallic systems reveal a synergistic
behavior by exposing more active sites on the silica support material with respect to
their monometallic counterparts. Besides, NaCl catalytic promoter has a strong
interaction particularly with the Cu sites on the Cu/Ru/SiO2 catalyst surface, altering
the electronic structure of Cu sites that favors to PO production.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12615076/index.pdf |
| Date | 01 September 2012 |
| Creators | Kalyoncu, Sule |
| Contributors | Onal, Isik |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | Access forbidden for 1 year |
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