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 unchanged chemically at the end of the reaction”

4

You can also check:

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 thatincreases the rate at which a chemical reactionapproaches equilibrium without itself becomingpermanently involved in the reaction

• You can look also in: Oxford English Dictionary, Merriam-Webster

5

Richardson, Principles of Catalyst Development, Plenum Press, 1989.

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

• <is present in minute concentrations>

6

Timeline of catalysis

From alchemy to chemistry

… - 1834

From empirics to science

1835-1897

The birth of industrial

catalysis

1898-1918

The increase in global

mobility by developing

catalytic fuel processes

1919-1945

From war to peace

1946-1970

Environmental catalysis

1970-20??

https://dx.doi.org/10.1023/A:1025001809516

Jöns Jacob

Berzelius,

seminal

work 1835

J. J. Berzelius 1835

• Berzelius coined the word catalysis, combining the Greek words 𝜅𝛼𝜏𝛼´ (down) and 𝜆𝜐𝜎𝜄𝜍 ´ (solution, loosening).

• In Chinese, catalyst = a marriage broker [Cuīhuàjì]

8

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)

催化剂You can also check:

Catalyst introduces a less difficultpath for molecules to follow

9

En

erg

y

Reaction

Grey: uncatalyzed

Green: catalyzed

Catalyst introduces a less difficultpath for molecules to follow

10

En

erg

y

Reaction

New reaction

intermediate

Grey: uncatalyzed

Green: catalyzed

Catalyst introduces a less difficultpath for molecules to follow

11

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 2.

En

erg

y

Reaction

Example: ammonia synthesis,

Haber-Bosch process

Catalyst introduces a less difficultpath for molecules to follow

12

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 2.

Also: https://www.chemguide.co.uk/physical/equilibria/haber.html

En

erg

y

Reaction

• Exothermic reaction

• Catalyst does not change the

overall energetics

• Activation energy:

Ehomogeneous >> Ecatalytic

Example: ammonia synthesis,

Haber-Bosch process

Interactions between catalyst & substrate should be not too storng nortoo 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 homogeneousvs heterogeneous catalysis1. 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 dealtfurther in this course)

(4. Photocatalysts, will not be dealt with further in 2018-2019)

15

More: Ross book, Chapter 1, Box 1.1

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

Figure 4.1: Julian Ross: Heterogeneous Catalysis - Fundamentals and Applications, © Elsevier 2012.

Link to electronic book here.

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

Catalysis: a tool for manipulatingselectivity

Catalyst: tool for selectivity. Case: synthesis gas H2 + CO

20

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p.5.

H2 + CO

Methane

Paraffinic hydrocarbons

Alcohols, aldehydes, and acids[Co/ThO2]

Methanol

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

From alchemy to chemistry

… - 1834

From empirics to science

1835-1897

The birth of industrial

catalysis

1898-1918

The increase in global

mobility by developing

catalytic fuel processes

1919-1945

From war to peace

1946-1970

Environmental catalysis

1970-20??

https://dx.doi.org/10.1023/A:1025001809516

Fluid Catalytic Cracking

Fischer-Tropsch

”The nitrogen problem”

NH3 synthesis

(Haber-Bosch)

Ostwald: “there is probably

no chemical reaction which

can not be influenced

catalytically”

Petrochemical industry & polymers

(& explosive automotive market)

(1962 Rachel Carson’s Silent Spring)

Pollution control

Berzelius: “Catalysis”Lead chamber

process, H2SO4

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 solidheterogeneous catalyst

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.

Three typical components of a solid heterogeneous catalyst

Active component: chemicalactivity

30

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.

Types, e.g.:

• Metals

• Semiconductor oxides and sulfides

• Insulator oxides and sulfides

31Source: https://iupac.org/what-we-do/periodic-table-of-elements/ ,

accessed 12.1.2019

https://en.wikipedia.org/wiki/Transition_metal, accessed 14.1.2019

Transition metals

are typical

active components

Active component: chemicalactivity

• Types, e.g.:

• Metals

• Semiconductor oxidesand sulfides

• Insulator oxides and sulfides

32

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.

Support: high surface area etc

33

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.

• Function:

• High surface area; Porosity

• Mechanical properties; Stability

• Dual functional activity

• Modification of active component

• Types, e.g.:

• High melting point oxides

• Clays

• Carbon

Some catalyst supports

34

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 31.

+ ZrO2, CeO2-ZrO2, TiO2, …

Catalysts contain”finely disintegrated metals”

35

Dispersion defined as

• D = Ns / Nt

• Ratio surface atoms vstotal 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/

Image: Richardson, Principles of Catalyst Development, Plenum Press, 1989.

Distribution of surface sites varieswith crystallite size

corner

edge

face

Promoters:”spices” of a catalyst

37

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 27.

• Function, on support:

• Structural

• Activity inhibition

• Activity promotion

• Function, on active component:

• Electronic

• Morphology

• Poisoning

Examples of promoters

38

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p.36.

Typical:

K basic

Cl acidic

Engineering features of a solidheterogeneous catalyst

Engineering features of a catalyst

40

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 24.

Engineering features of a catalyst

41

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 24.

Deactivation mechanisms

Texture parameters of a solidcatalyst

42

Richardson, Principles of Catalyst Development, Plenum Press, 1989, p. 11.

Specific surface areas vary from ~10 to ~1000 m2/g

Many shapes and sizes

43

http://www.oxeeco.in/sites/default/files/images/catalysts2.jpg

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 researchhttps://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