CHEM-E1130 Introduction to catalysis
Prof. Riikka Puurunen 14.1.2018 Contents
1. Definition of catalysis and catalyst 2. Classification of catalysts 3. Seven steps of a heterogeneously catalyzed reaction 4. Catalysis: a tool for manipulating selectivity 5. Significance of catalysis? 6. Components of a solid heterogeneous catalyst 7. Engineering features of a solid heterogeneous catalyst + Conclusion & take-home message Definition of catalysis and catalyst Definition of ”catalysis”?
• IUPAC Gold Book, Compendium of Chemical Terminology • https://goldbook.iupac.org
• ”Catalysis: The action of a catalyst”
• Merriam-Webster: “a modification and especially increase in the rate of a chemical reaction induced by material You can also check: unchanged chemically at the end of the reaction”
4 Definition of ”catalyst”?
• IUPAC:” A substance that increases the rate of a reaction without modifying the overall standard Gibbs energy change in the reaction ” • Richardson: A catalyst is a substance that increases the rate at which a chemical reaction approaches equilibrium without itself becoming permanently involved in the reaction
• You can look also in: Oxford English Dictionary, Merriam- Webster
Richardson, Principles of Catalyst Development, Plenum Press, 1989.
5 In other words, a catalyst:
1. Increases the chemical reaction rate 2. Does not influence the position of thermodynamic equilibrium 3. Is not (permanently) changed in the catalysed reaction
•
6 Timeline of catalysis Jöns Jacob From alchemy to chemistry Berzelius, … - 1834 seminal From empirics to science work 1835 1835-1897 The birth of industrial catalysis 1898-1918 The increase in global mobility by developing catalytic fuel processes https://dx.doi.org/10.1023/A:1025001809516 1919-1945 From war to peace 1946-1970 Environmental catalysis 1970-20?? J. J. Berzelius 1835
• Berzelius coined the word catalysis, combining the Greek words 휅훼휏훼´ (down) and 휆휐𝜎휄𝜍 ´ (solution, loosening).
• In Chinese, catalyst = a marriage broker [Cuīhuàjì]
催化剂 You can also check:
More, e.g.: http://dx.doi.org/10.1002/9781119181286 Ross, Heterogeneous Catalysis, Chapter 1, Figure (daguerrotype): https://en.wikipedia.org/wiki/J%C3%B6ns_Jacob_Berzelius Wikipedia: Jöns Jacob Berzelius (1779-1848) 8 Catalyst introduces a less difficult path for molecules to follow
Grey: uncatalyzed
Green: catalyzed
Energy Energy
Reaction
9 Catalyst introduces a less difficult path for molecules to follow
Grey: uncatalyzed
Green: catalyzed New reaction
intermediate Energy Energy
Reaction
10 Catalyst introduces a less difficult path for molecules to follow Example: ammonia synthesis,
Haber-Bosch process Energy
Reaction
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 2.
11 Catalyst introduces a less difficult path for molecules to follow Example: ammonia synthesis, Haber-Bosch process
Energy • Exothermic reaction • Catalyst does not change the overall energetics • Activation energy:
Ehomogeneous >> Ecatalytic Reaction
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 2. Also: https://www.chemguide.co.uk/physical/equilibria/haber.html 12 Interactions between catalyst & substrate should be not too storng nor too weak but ”just right” (Sabatier)
Volcano curves often encountered. There, measure of catalytic activity… • Reaction rate • Turn-over frequency (TOF) • etc … plotted against a measure of binding energy
More, e.g.: http://dx.doi.org/10.1002/9781119181286 Richardson, Principles of Catalyst Development, Plenum Press, 1989 Classification of catalysts Typically divided to homogeneous vs heterogeneous catalysis
1. Homogeneous: catalyst is in the same phase as reactants (and products) • Gas-gas, liquid-liquid, solid-solid 2. Heterogeneous: reactants and catalyst in a different phase • Phase not only solid, liquid, and gas, but also immiscible liquids, e.g. oil and water. • Most often: solid catalyst with gaseous and/or liquid reactant 3. Enzymes form their own (biocatalyst) group (will not be dealt further in this course) (4. Photocatalysts, will not be dealt with further in 2018-2019) More: Ross book, Chapter 1, Box 1.1
15 Some examples
1. Homogeneous catalysts: most typically liquids. Examples: • Liquid-liquid: hydrolysis of esters by acids (more examples to follow in this coures)
• Vapor-vapor: oxidation of SO2 by NO2 - • Solid-solid: decomposition of potassium chlorate (K+ ClO3 ) by MnO2
2. Heterogeneous catalysts: most typically solids. Examples
• NH3 process; many more examples to follow during course Seven steps of a heterogeneously catalyzed reaction Seven steps of a heterogeneously catalyzed reaction
1. External diffusion 2. Internal diffusion 3. Adsorption 4. Surface reaction 5. Desorption of product 6. Internal diffusion of product 7. External diffusion of product
Figure 4.1: Julian Ross: Heterogeneous Catalysis - Fundamentals and Applications, © Elsevier 2012. Link to electronic book here. Catalysis: a tool for manipulating selectivity Catalyst: tool for selectivity. Case: synthesis gas H2 + CO Methane
Paraffinic hydrocarbons
H2 + CO [Co/ThO2] Alcohols, aldehydes, and acids
Methanol
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p.5.
20 Catalysis: tool of Green Chemistry
Anastas et al. Applied Catalysis A: General 221 (2001) 3–13, https://doi.org/10.101 6/S0926- 860X(01)00793-1 Significance of catalysis? Timeline Lead chamber Berzelius: “Catalysis” process, H2SO4 From alchemy to chemistry Ostwald: “there is probably no chemical reaction which … - 1834 can not be influenced From empirics to science catalytically” 1835-1897 The birth of industrial catalysis ”The nitrogen problem” 1898-1918 NH3 synthesis Fluid Catalytic Cracking (Haber-Bosch) The increase in global Fischer-Tropsch mobility by developing catalytic fuel processes 1919-1945 Petrochemical industry & polymers (& explosive automotive market) From war to peace 1946-1970 (1962 Rachel Carson’s Silent Spring) Environmental catalysis Pollution control 1970-20??
https://dx.doi.org/10.1023/A:1025001809516 How a centrury of ammonia synthesis changed the world, Erisman et al., Nature Geoscience 1 (2008) 636-639. ”Carbon dioxide crisis”, 2018
• Empty shop shelves in summer for beer & soft drinks (with Fifa World Cup!)
• Shortage of CO2 because of… • … shutdowns & maintenance in
NH3 production
https://www.chemistryworld.com/news/explainer-the-carbon-dioxide-crisis- /3009216.article, accessed 12.1.2019 Significance of catalysis?
Without catalysts, there would not be • Modern chemical industry • Oil refining • Polymer production • Possibility to control emissions • Enough food for the earth’s population How large is the catalyst market?
• Market studies in 2013 have estimated the total sales of catalysts to be between $15 and $19 billion per year, and to rise 4−5% per year. • Munnik, de Jongh, de Jong, Recent developments in the synthesis of supported catalysts, Chem. Rev. 115 (2015) 6687. (Open Access) http://dx.doi.org/10.1021/cr500486u --> • https://www.transparencymarketresearch.com/global-refinery-catalyst-market.html • https://www.freedoniagroup.com/world-catalysts.html
• ~850 catalysts commercially available • Source: Prof. Jiri Cejka, plenary lecture at EuropaCat 2017
Munnik, de Jongh, de Jong, Recent developments in the synthesis of supported catalysts, Chem. Rev. 115 (2015) 6687. (Open Access) http://dx.doi.org/10.1021/cr500486u Components of a solid heterogeneous catalyst Three typical components of a solid heterogeneous catalyst
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27. Active component: chemical activity
Types, e.g.: • Metals • Semiconductor oxides and sulfides • Insulator oxides and sulfides
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.
30 Transition metals are typical active components
Source: https://iupac.org/what-we-do/periodic-table-of-elements/ , 31 accessed 12.1.2019 https://en.wikipedia.org/wiki/Transition_metal, accessed 14.1.2019 Active component: chemical activity
• Types, e.g.: • Metals • Semiconductor oxides and sulfides • Insulator oxides and sulfides
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.
32 Support: high surface area etc
• Function: • High surface area; Porosity • Mechanical properties; Stability • Dual functional activity • Modification of active component • Types, e.g.: • High melting point oxides • Clays • Carbon
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.
33 Some catalyst supports
+ ZrO2, CeO2-ZrO2, TiO2, …
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 31.
34 Catalysts contain ”finely disintegrated metals”
Dispersion defined as
• D = Ns / Nt • Ratio surface atoms vs total atoms (typically used for metals)
Image: Ross, Heterogeneous catalysis, Chapter 3 (Fig. 3.5) Image: Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 31. More, e.g.: http://dx.doi.org/10.1002/9781119181286 Sabatier Nobel lecture 1912: https://www.nobelprize.org/prizes/chemistry/1912/sabatier/lecture/ 35 Distribution of surface sites varies with crystallite size
corner edge face
Image: Richardson, Principles of Catalyst Development, Plenum Press, 1989. Promoters:”spices” of a catalyst
• Function, on support: • Structural • Activity inhibition • Activity promotion • Function, on active component: • Electronic • Morphology • Poisoning
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.
37 Examples of promoters
Typical: K basic Cl acidic
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p.36.
38 Engineering features of a solid heterogeneous catalyst Engineering features of a catalyst
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 24.
40 Engineering features of a catalyst
Deactivation mechanisms
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 24.
41 Texture parameters of a solid catalyst Specific surface areas vary from ~10 to ~1000 m2/g
Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 11.
42 Many shapes and sizes
http://www.oxeeco.in/sites/default/files/images/catalysts2.jpg
43 Conclusion & take-home message Take-home message, 1st lecture
• You know the definition and understand the significance of catalysis • This was the first lesson to learn to ”speak the language of catalysis”. Field-specific words encountered.
Next lecture • Timeline of industrial catalysis, three significant historical examples, more ”language of catalysis” • Adsorption excercise will be shared Extra slides • More on market research Extra: More on a market research https://www.freedoniagroup.com/world-catalysts.html (Aalto does not own this report) • Openly available information: • World demand for catalysts will grow 4.8 percent per year to $20.6 billion in 2018. Growth will be led by a rebound in the chemical and polymer industries, most notably in developed economies hit hard by the recession. The fastest advances, however, will occur in developing areas such as the Asia/Pacific and Africa/Mideast regions. • This study analyzes the $16.3 billion world catalyst industry. It presents historical demand data (2003, 2008 and 2013) and forecasts (2018 and 2023) by material (e.g., metals, organometallic materials, chemicals, zeolites, enzymes), product (e.g., organic synthesis, oxidation, synthesis gas, hydrogenation, hydroprocessing, fluid catalytic cracking, alkylation, Ziegler-Natta, reaction initiators), market, (e.g., chemical synthesis, petroleum refining, polymerization), world region, and for 18 countries. • The study also considers market environment factors, details industry structure, evaluates company market share and profiles 34 industry players, including BASF, WR Grace, and Johnson Matthey. ”Everything is a catalyst for something”
Quoted in: James T. Richardson, Principles of Catalyst Development, 1989 (p. 49)
Source: https://twitter.com/openculture/status/840318207667785728