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Catalytic Reaction Of Propylene To Propylene Oxide On Various CatalystsKalyoncu, Sule 01 September 2012 (has links) (PDF)
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
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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.
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Development Of Sol-gel Catalysts By Use Of Fast Combinatorial Synthesis And High Throughput Testing Techniques For Catalytic Oxidation Of Propylene To Propylene OxideDuzenli, Derya 01 August 2003 (has links) (PDF)
Propylene oxide (PO) is an important raw material for the chemical industry,
which is produced commercially by the chlorohydrin process and
hydroperoxide process. However the deficiencies in these processes have
given rise to considerable interest in the development of a direct route to PO
that does not produce by-products or coproducts.
The development of novel, active and selective catalysts for gas phase
oxidation of propylene using molecular oxygen were studied via testing a
large number of catalysts by high-throughput screening method over
combinatorially prepared different catalytic system in this study.
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The promoted and un-promoted silver (Ag), copper (Cu), manganese (Mn)
mono and bimetallic catalytic system over high and low surface area silica,
alumina, titanium oxide and titanium-silicate supports were prepared by
single step sol-gel method and by incipient wetness method. The study to
determine the most effective catalyst and promoter in the epoxidation
reaction with different reaction conditions, showed that potassium (K)-
promoted Cu metal supported over high surface area silica favored the PO
production at a high reaction temperature (350 ° / C) and oxygen rich
atmosphere (C3H6/O2=1.0).
The catalyst showed high and low propylene oxide productivity was
investigated by some of the characterization techniques. The highlydispersed
copper particle over silica support was determined by XRD, TEM
and XPS techniques. The only change between promoted and un-promoted
catalyst was found out in the temperature dependence of propylene
consumption and PO production rate. It was inferred that potassium (K) only
neutralizes the acid sites of silica.
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Development of stirred well filtration as a high-throughput technique for downstream bioprocessingKazemi, Amir Sadegh 11 1900 (has links)
Micro-scale processing (MSP) techniques are miniaturized version of upstream and downstream conventional unit operations that are designed to accelerate the pace of bioprocess design and development. Previous ‘dead end’ filtration studies have demonstrated the usefulness of this concept for membrane filtration processes. However, these experiments were performed without stirring which is the most common strategy to control the effects of concentration polarization and fouling on filtration performance.
In this work, the pressure-driven stirred conditions of a conventional stirred-cell module were integrated with a 96-well filter plate to develop a high throughput technique called ‘stirred-well filtration’ (SWF). The design allowed for up to eight constant flux filtration experiments to be conducted at once using a multi-rack programmable syringe pump and a magnetic lateral tumble stirrer. An array of pressure transducers was used to monitor the transmembrane pressure (TMP) in each well. The protein sieving behavior and fouling propensity of Omega™ ultrafiltration membranes were assessed via a combination of hydraulic permeability measurements and protein sieving tests in constant filtrate flux mode. The TMP profile during filtration of bovine serum albumin (BSA) solution was strongly dependent on the stirring conditions – for example the maximum TMP in the stirred wells were an average of 7.5, 3.8, and 2.6 times lower than those in the unstirred wells at filtrate fluxes of 12, 36, and 60 LMH (5, 15, and 25 μL/min) respectively. The consistency of the data across different wells for the same stirring condition was very good. To demonstrate the effectiveness of the SWF technique, the eight tests for a simple 2^2 factorial design-of-experiments (DOE) test with duplicates was run to evaluate the effect of solution pH and salt concentration on protein filtration. The combination of SWF with statistical methods such as DOE is shown to be an effective strategy for high-throughput optimization of membrane filtration processes. / Dissertation / Master of Applied Science (MASc)
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