Podcast
Questions and Answers
Which of the following is the primary role of a catalyst in a chemical reaction?
Which of the following is the primary role of a catalyst in a chemical reaction?
- To increase the potential energy of the products, making the reaction more exothermic.
- To increase the temperature at which the reaction occurs.
- To shift the equilibrium towards product formation, increasing the equilibrium constant.
- To accelerate the reaction rate by providing an alternative reaction pathway with a lower activation energy. (correct)
A chemical manufacturing plant wants to implement a catalytic process. Which characteristics of catalysts makes them attractive for industrial applications?
A chemical manufacturing plant wants to implement a catalytic process. Which characteristics of catalysts makes them attractive for industrial applications?
- Catalysts increase the activation energy of reactions.
- Catalysts are consumed in the reaction, which reduces waste.
- Catalysts are always more expensive than non-catalytic alternatives, resulting in high investment
- Catalysts operate under industrially feasible conditions, such as lower pressure and temperature. (correct)
A researcher is studying a reaction where the catalyst and reactants are in the same phase. This system is characteristic of which type of catalysis?
A researcher is studying a reaction where the catalyst and reactants are in the same phase. This system is characteristic of which type of catalysis?
- Homogeneous catalysis (correct)
- Surface catalysis
- Electro catalysis
- Heterogeneous catalysis
In the context of catalysis, what is suggested by the classification of catalysts based on 'Catalyst Action'?
In the context of catalysis, what is suggested by the classification of catalysts based on 'Catalyst Action'?
Which catalytic application directly contributes to reducing air pollution from vehicles?
Which catalytic application directly contributes to reducing air pollution from vehicles?
A chemical plant utilizes a catalytic process that involves gaseous reactants being converted into liquid products using a solid catalyst. Which classification best describes this catalytic system?
A chemical plant utilizes a catalytic process that involves gaseous reactants being converted into liquid products using a solid catalyst. Which classification best describes this catalytic system?
What characteristic of a catalyst is responsible for increasing the rate of a chemical reaction?
What characteristic of a catalyst is responsible for increasing the rate of a chemical reaction?
A chemist needs to choose between a homogeneous and a heterogeneous catalyst for a specific reaction. Which is a major drawback of homogeneous catalysts compared to heterogeneous catalysts?
A chemist needs to choose between a homogeneous and a heterogeneous catalyst for a specific reaction. Which is a major drawback of homogeneous catalysts compared to heterogeneous catalysts?
What is the role of 'promoters' in heterogeneous catalysis?
What is the role of 'promoters' in heterogeneous catalysis?
Which property of heterogeneous catalysts is described as the measure of the number of active sites available for reaction?
Which property of heterogeneous catalysts is described as the measure of the number of active sites available for reaction?
A researcher is tasked with identifying the crystalline structure of a newly synthesized solid catalyst. Which characterization technique is most suitable for this purpose?
A researcher is tasked with identifying the crystalline structure of a newly synthesized solid catalyst. Which characterization technique is most suitable for this purpose?
A catalytic converter in automobiles is designed to reduce harmful emissions. Which substance is reduced by catalysts in catalytic converters?
A catalytic converter in automobiles is designed to reduce harmful emissions. Which substance is reduced by catalysts in catalytic converters?
How do catalysts affect the thermodynamic equilibrium of a reversible reaction?
How do catalysts affect the thermodynamic equilibrium of a reversible reaction?
For a solid catalyst in a heterogeneous reaction, what is the correct order of steps that occur during the catalytic process?
For a solid catalyst in a heterogeneous reaction, what is the correct order of steps that occur during the catalytic process?
What is the purpose of 'hydrotreating’ in the context of environmental applications of catalysis?
What is the purpose of 'hydrotreating’ in the context of environmental applications of catalysis?
In the production of polymers, what is the primary role of catalysts?
In the production of polymers, what is the primary role of catalysts?
Which of the following is a typical application of heterogeneous catalysts that utilize metal oxides?
Which of the following is a typical application of heterogeneous catalysts that utilize metal oxides?
Which of the following statements is correct regarding the use of heterogeneous catalysts in chemical reactions?
Which of the following statements is correct regarding the use of heterogeneous catalysts in chemical reactions?
Which technique is used to study the adsorption of gases on a catalyst surface?
Which technique is used to study the adsorption of gases on a catalyst surface?
Which of the surface chemical properties is essential for enhancing the function of heterogeneous catalysts?
Which of the surface chemical properties is essential for enhancing the function of heterogeneous catalysts?
Flashcards
What are Catalysts?
What are Catalysts?
Substances that speed up chemical reactions without being consumed themselves.
Catalysis and Pressure
Catalysis and Pressure
Catalysts allow industrial processes to occur at lower pressures, making them industrially feasible.
Catalysis and Activation Energy
Catalysis and Activation Energy
Catalysts provide an alternate reaction pathway with a lower activation energy.
Catalyst Classification by State
Catalyst Classification by State
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Catalyst Classification by Nature
Catalyst Classification by Nature
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Homogeneous vs Heterogeneous Catalysis
Homogeneous vs Heterogeneous Catalysis
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Catalyst Action Types
Catalyst Action Types
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Applications of Catalysis
Applications of Catalysis
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Heterogeneous Catalyst Properties
Heterogeneous Catalyst Properties
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Steps in Heterogeneous Catalysis
Steps in Heterogeneous Catalysis
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Catalyst Characterization Techniques
Catalyst Characterization Techniques
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Homogeneous Catalysis - Activity and Stability
Homogeneous Catalysis - Activity and Stability
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Heterogeneous Catalyst - Recovery and Cost
Heterogeneous Catalyst - Recovery and Cost
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Catalysis and Reaction Rate
Catalysis and Reaction Rate
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Catalytic Converters
Catalytic Converters
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Study Notes
- Catalysis is an introduction, by M. F. Baidoo on 22.01.2024
Background
- Catalysts act as the workhorses in chemical transformations within the industry
- Approximately 85-90% of chemical industry products are obtained via catalytic processes, making catalysts indispensable
- Catalysts enable industrial processes to occur under feasible pressure conditions
What is a Catalyst
- A catalyst accelerates chemical reactions without being changed at the end
- Catalysts provide a lower activation energy pathway, increasing reaction rates
- They help overcome the difficulty of maintaining high temperatures and pressures in reactors
- Catalysts address thermodynamic limitations on the conditions for product formation
Catalyst Classification
- Catalysts can be classified based on their state, nature and system
- State: Gas, Liquid, solid
- Nature: Inorganic (gases, metals, metal oxides, inorganic acids, etc) or Organic (organic acids, enzymes, etc)
- System: Multiphase / Single phase
Homogeneous catalysts
- Soluble catalysts in a single phase, commonly liquid
Catalyst Action
- Acid-base catalysis
- Enzymatic/biocatalysis
- Photocalysis
- Electrocatalysis
Applications of Catalysis
- Refineries
- Energy
- Petrochemistry
- Fine chemicals
- Gas conversion
- Fuels
- Food and drugs
- Environment
Applications of Catalysis include
- Chemical and Petrochemical Industry: Refinery, bulk chemicals, agricultural products, oil and gas processing
- Environmental: Selective processes, flue gas cleaning (exhaust, HC, CO, NOx), hydrotreating (de scaling, HDS, HDN, HDO...)
- Energy Production: Fuels (oil, gas, biomass), catalytic combustion (gas fired power plants), fuel cells, hydrogen production
- Domestic appliances: Catalytic heaters and self-cleaning stoves
Homogenous Catalysis in Chemical/Petrochemical Industry
- Carbonylation uses methanol and carbon monoxide to create acetic acid with Rh or Co
- Hydrocarboxylation involves alkene, water, and carbon monoxide to to create carboxylic acid using Pd
- Hydroformylation uses propylene, CO, Hâ‚‚ to create n-Butyraldehyde with Rh or Co
Heterogeneous Catalysis in the Petrochemical Industry
- Catalytic cracking of crude oil uses Zeolites
- Hydrotreating of crude oil occurs with Co-Mo, Ni-Mo, Ni-W (sulfidic form)
Homogeneous vs Heterogeneous Catalysis
- Homogeneous catalysts offer higher activity and reproducible results compared to heterogeneous catalysts
- Homogeneous catalysts have relatively higher selectivity and can be easy to optimized
- Heterogeneous sites are difficult to control and require higher temps
- Homogeneous catalysts require lower temperatures that is lesser than 250ºC
- Heterogeneous catalysts use higher volumes at low cost and easy catalyst recovery
- Homogeneous catalysts use low volume at high value and recovery is difficult
- Heterogeneous catalysts are not well-defined, heterogeneous, require tuning, and have limited accessibility
- Homogeneous catalysts have molecular active sites that are very well defined, uniform, tunable, & accessible and offer optimization of stirring
Heterogeneous Catalytic Materials consist of
- Metals such as Pt, Rh, Fe, Cu, Co used in Hydrogenation
- Non-stoichiometric oxides (p- and n-type semiconductors) such as ZnO, TiO2 used in Partial oxidation
- Insulating oxydes such as Al2O3, SiO2 used in cracking
Properties of solid catalysts include
- Chemical composition of the bulk and surface of the solid
- Surface area and porosity (micro, meso and macro)
- Bulk solid structure, phase composition, crystallite size
- Surface morphology (shape, texture and distribution of material at a surface)
Steps of a Heterogeneous Catalytic Reaction
- Diffusion of reactant to the surface
- Adsorption of the reactant
- Reaction catalyst
- Desorption
- Diffusion from the surface
Catalyst Characterization Techniques Include
- Structural Analysis, BET surface area, XRD
- Spectroscopic techniques such as Infrared and Raman spectroscopy
- Microscopic techniques such as SEM and TEM
- Chemisorption
- Temperature programmed methods such as oxidation, reduction
- Nuclear Magnetic Resonance
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