Catalytic Converter used on automobiles in Europe: Converts CO, Hydrocarbons , and oxides of nitrogen into Water, Carbon Dioxide, and Nitrogen. Reduces the emissions of these harmful
Catalytic Converter used on automobiles in Europe: Converts CO, Hydrocarbons, and oxides of nitrogen into Water, Carbon Dioxide, and Nitrogen. Reduces the emissions of these harmful gases.
What is a Catalyst?
A Catalyst is a substance that initiates or accelerates a chemical reaction without itself
being affected. Catalysts provide an alternative reaction mechanism with a lower activation energy.
Introduction to Catalysts Catalysts increase the rates
of both the forward and reverse reactions equally. Thus, they reduce the time to reach the equilibrium. They have no effect on either the yield of the reaction or the
equilibrium constants. Reaction with
Catalyst Vs. without Catalyst>>>
General Uses Of CatalystsMeat productsCatalytic Converters help reduce
pollutionAntibiotics “Biological” DetergentsManufacturing of PetroleumDifferent types of Motors (thrusters)
Recyclable Catalysts Replacing hazardous solvents
with water and being more efficient with resources are methods that chemists use to reduce the environmental impact of their reactions—a central goal of the ‘green chemistry’ movement. Yasuhiro Uozumi from the RIKEN Advanced Science Institute in Wako has developed recyclable catalysts that selectively generate chiral organic molecules in water, considered a nearly ideal green chemical process.
Goal: Improve quality of loading of reformer catalyst
Goal: Improve quality of loading of reformer catalyst
Tools: PETROVAL uses the UNIDENSE technology to load reformer tubes in ammonia, methanol and hydrogen plants. gives improved homogeneity and density, and shorter loading time, than pre-socked catalyst
Benefits: Quick loading No pre-socking required No or very little tube vibration Uniform dPs (PETROVAL
guarantees ±5%) No bridging or gaps in catalyst
inside the tubes
Types of CatalystsHomogeneous Catalysts
---Catalyst is in the same phase as reactants
---Increase rate of reaction caused by catalyst allowing for reaction to occur with alternative mechanism with lower activation energy
---Catalyst is consumed at one stage in the mechanism and reformed at a later stage
---Liquid Phase
*Source-Green Damji- Chemistry 2nd Edition p.241
Heterogeneous Catalysts---Catalyst is in different phase to
reactants---Catalyst provides reactive surface
where reaction can take place; reactants are absorbed onto the surface
---This process weakens the bonding in molecules and brings them into close contact; reaction occurs on the surface and the products are desorbed; this frees the surface for further reaction
---Solid/Gas Phase*Source-Green Damji- Chemistry 2nd
Edition p.241
HOMOGENEOUS CATALYSIS WORKFLOW
The Homogeneous Catalysis Workflow uses liquid and solid handling robotics, parallel pressure reactors, and standard analytical screens to study up to hundreds of reactions every day under different temperature/pressure conditions
Advantages and DisadvantagesHomogeneous
CatalystsAdvantages---all the catalyst is
exposed to the reactant, easily modified, reaction mechanisms are well understood by scientists, easy process of diffusion and heat transfer, well defined active site
Disadvantages--- can be difficult to remove from the products for reuse
Heterogeneous Catalysts
Advantages---easily removed from products by filtration, easily recycled
Disadvantages---only effective on the surface, reaction mechanisms are poorly understood in general, poorly defined active site
Low Temp. Oxidation Catalyst <<<Low Temperature
Oxidation Catalyst—reduces CO emissions as well as formaldehydes and other lightweight hydrocarbons
MODES OF ACTION Heterogeneous One or more of
reactants adsorbed(stick to surface) onto surface in the active site, Product molecules are desorbed, or break away.
Homogeneous Catalyst in same
phase as reactants transition metal
compounds as catalysts is convenient- their ability to change oxidation state-avoids problem of wrong collisions for reaction to occur
CatCart Immiscible phases
The CatCart® - created to make the process of hydrogenation easier and more efficient., steel tube packed with heterogeneous catalyst, filter system at both ends of tube allows liquid to pass through the column and prevents catalyst from leaking out
two immiscible aqueous-organic phases investigated for different organic transformations =the onium salt forms a distinct liquid phase which is catalyst-philic, and contains - or coats - the metal catalyst methods of catalyst separation and product recovery, as well as advantages on catalytic efficiency, have been demonstrated.
Factors that determine choice of catalystsselectivity (produce only the desired product)efficiencyability to work under mild/severe conditionsenvironmental impactproblems caused by catalysts becoming poisoned by impurities.
RTM is a low pressure moulding process, where a mixed resin and catalyst are injected into a closed mould containing a fibre pack or preform. When the resin has cured the mould can be opened and the finished component
removed. The Advantages and Benefits of using
RTM: Components will have good surface
finish on both sides Selective reinforcement and accurate
fibre management is achievable Ability to build-in fibre volume fraction
loadings up to 65% Uniformity of thickness and fibre loading,
resulting in uniform shrinkage Tooling costs comparatively low
compared to other manufacturing processes
Uses only low pressure injection Low volatile emission during processing Ability to produce near net shape
mouldings, reducing material wastage Process can be automated, resulting in
higher production rates with less scrap Ability to mould complex structural and
hollow shapes
Bibliography of Photos http://www.nasa.gov/centers/langley/images/content/351625main_low-temp-ox-catalyst_516-387.gif http://www.plastech.co.uk/Images/JEC%20RTM%20Diagram.jpg
http://www.vajdagroup.com/images/stories/industry/our%20offer/production/RTM_1.jpg http://www.symyx.com/products/images/homogeneous_catalysis_4.jpg
http://www.thalesnano.com/files/image/products/catcarts.jpg http://www.rikenresearch.riken.jp/images/figures/hi_3392.jpg http://www.basf.com/group/corporate/en/function/conversions:/publish/content/innovations/innovation-award/2007/images/2007-catalysts-170x170.jpg
http://www.petroval.fr/image/tubeloading_250.gif http://ene.web.psi.ch/Combustion/comchem/Fig1a.gif http://www.unive.it/media/allegato/dipartimenti/Dip%20SA/Selva_image037.jpg http://www.ace.mmu.ac.uk/Resources/Fact_Sheets/Key_Stage_4/Transport/images/06a.jpg
Other Sourceshttp://gcserevision101.files.wordpress.com/2009/02/energy-level-diagram-activation-energy.jpg
Green, Damji Chemistry: For Use With The International Baccalaureate Diploma Programmme
http://www.essortment.com/all/howenzymeswork_rkyf.htm
file:///C:/DOCUME~1/SAMMYT~1/LOCALS~1/Temp/chemistry_hl_paper_2a.pdf
http://www.ibo.org/diploma/curriculum/examples/samplepapers/documents/gp4_chemistyhl3.pdf
http://web.uvic.ca/~mcindoe/423/homovshet.pdf
http://www.chemguide.co.uk/physical/catalysis/introduction.html