Catalysis.pdf

Catalysis

Catalyst redirects here. For other uses, see Catalyst(disambiguation).Catalysis is the increase in the rate of a chemical re-

An air lter that utilizes low-temperature oxidation catalyst usedto convert carbon monoxide to less toxic carbon dioxide at roomtemperature. It can also remove formaldehyde from the air.

action due to the participation of an additional substancecalled a catalyst.[1] With a catalyst, reactions occur fasterand with less energy. Because catalysts are not con-sumed, they are recycled. Often only tiny amounts arerequired.[2]

1 Technical perspectiveIn the presence of a catalyst, less free energy is requiredto reach the transition state, but the total free energy fromreactants to products does not change.[1] A catalyst mayparticipate in multiple chemical transformations. The ef-fect of a catalyst may vary due to the presence of othersubstances known as inhibitors or poisons (which reducethe catalytic activity) or promoters (which increase theactivity). The opposite of a catalyst, a substance that re-duces the rate of a reaction, is an inhibitor.[1]

Catalyzed reactions have a lower activation energy (rate-limiting free energy of activation) than the correspond-ing uncatalyzed reaction, resulting in a higher reactionrate at the same temperature and for the same reac-tant concentrations. However, the detailed mechanicsof catalysis is complex. Catalysts may aect the re-action environment favorably, or bind to the reagentsto polarize bonds, e.g. acid catalysts for reactions of

carbonyl compounds, or form specic intermediates thatare not produced naturally, such as osmate esters inosmium tetroxide-catalyzed dihydroxylation of alkenes,or cause dissociation of reagents to reactive forms, suchas chemisorbed hydrogen in catalytic hydrogenation.Kinetically, catalytic reactions are typical chemical reac-tions; i.e. the reaction rate depends on the frequency ofcontact of the reactants in the rate-determining step. Usu-ally, the catalyst participates in this slowest step, and ratesare limited by amount of catalyst and its activity. Inheterogeneous catalysis, the diusion of reagents to thesurface and diusion of products from the surface can berate determining. A nanomaterial-based catalyst is an ex-ample of a heterogeneous catalyst. Analogous events as-sociated with substrate binding and product dissociationapply to homogeneous catalysts.Although catalysts are not consumed by the reaction it-self, they may be inhibited, deactivated, or destroyed bysecondary processes. In heterogeneous catalysis, typicalsecondary processes include coking where the catalyst be-comes covered by polymeric side products. Additionally,heterogeneous catalysts can dissolve into the solution in asolidliquid system or sublimate in a solidgas system.

2 Background

The production of most industrially important chemicalsinvolves catalysis. Similarly, most biochemically signif-icant processes are catalysed. Research into catalysis isa major eld in applied science and involves many ar-eas of chemistry, notably organometallic chemistry andmaterials science. Catalysis is relevant to many aspectsof environmental science, e.g. the catalytic converter inautomobiles and the dynamics of the ozone hole. Cat-alytic reactions are preferred in environmentally friendlygreen chemistry due to the reduced amount of wastegenerated,[3] as opposed to stoichiometric reactions inwhich all reactants are consumed and more side prod-ucts are formed. The most common catalyst is the hy-drogen ion (H+). Many transition metals and transitionmetal complexes are used in catalysis as well. Catalystscalled enzymes are important in biology.A catalyst works by providing an alternative reactionpathway to the reaction product. The rate of the reactionis increased as this alternative route has a lower activationenergy than the reaction route not mediated by the cata-lyst. The disproportionation of hydrogen peroxide creates

1

2 3 GENERAL PRINCIPLES

water and oxygen, as shown below.

2 H2O2 2 H2O + O2

This reaction is preferable in the sense that the reac-tion products are more stable than the starting mate-rial, though the uncatalysed reaction is slow. In fact,the decomposition of hydrogen peroxide is so slow thathydrogen peroxide solutions are commercially available.This reaction is strongly aected by catalysts such asmanganese dioxide, or the enzyme peroxidase in organ-isms. Upon the addition of a small amount of manganesedioxide, the hydrogen peroxide reacts rapidly. This ef-fect is readily seen by the eervescence of oxygen.[4] Themanganese dioxide is not consumed in the reaction, andthus may be recovered unchanged, and re-used indef-initely. Accordingly, manganese dioxide catalyses thisreaction.[5]

3 General principles

3.1 UnitsCatalytic activity is usually denoted by the symbol z [6]and measured in mol/s, a unit which was called katal anddened the SI unit for catalytic activity since 1999. Cat-alytic activity is not a kind of reaction rate, but a propertyof the catalyst under certain conditions, in relation to aspecic chemical reaction. Catalytic activity of one katal(Symbol 1 kat = 1mol/s) of a catalyst means an amountof that catalyst (substance, in Mol) that leads to a net re-action of one Mol per second of the reactants to the re-sulting reagents or other outcome which was intended forthis chemical reaction. A catalyst may and usually willhave dierent catalytic activity for distinct reactions. Seekatal for an example.There are further derived SI units related to catalytic ac-tivity, see the above reference for details.

3.2 Typical mechanismMain article: catalytic cycle

Catalysts generally react with one or more reactants toform intermediates that subsequently give the nal reac-tion product, in the process regenerating the catalyst. Thefollowing is a typical reaction scheme, whereC representsthe catalyst, X and Y are reactants, and Z is the productof the reaction of X and Y:

X + C XC (1)Y + XC XYC (2)XYC CZ (3)CZ C + Z (4)

Although the catalyst is consumed by reaction 1, it is sub-sequently produced by reaction 4, so for the overall reac-tion:

X + Y Z

As a catalyst is regenerated in a reaction, often only smallamounts are needed to increase the rate of the reaction.In practice, however, catalysts are sometimes consumedin secondary processes.As an example of a detailed mechanism at the micro-scopic level, in 2008 Danish researchers rst revealedthe sequence of events when oxygen and hydrogen com-bine on the surface of titanium dioxide (TiO2, or ti-tania) to produce water. With a time-lapse seriesof scanning tunneling microscopy images, they deter-mined the molecules undergo adsorption, dissociationand diusion before reacting. The intermediate reactionstates were: HO2, H2O2, then H3O2 and the nal reac-tion product (water molecule dimers), after which the wa-ter molecule desorbs from the catalyst surface.[7][8]

3.3 Reaction energetics

Generic potential energy diagram showing the eect of a catalystin a hypothetical exothermic chemical reaction X + Y to give Z.The presence of the catalyst opens a dierent reaction pathway(shown in red) with a lower activation energy. The nal resultand the overall thermodynamics are the same.

Catalysts work by providing an (alternative) mechanisminvolving a dierent transition state and lower activationenergy. Consequently, more molecular collisions havethe energy needed to reach the transition state. Hence,catalysts can enable reactions that would otherwise beblocked or slowed by a kinetic barrier. The catalyst mayincrease reaction rate or selectivity, or enable the reactionat lower temperatures. This eect can be illustrated withan energy prole diagram.In the catalyzed elementary reaction, catalysts do notchange the extent of a reaction: they have no eect onthe chemical equilibrium of a reaction because the rateof both the forward and the reverse reaction are both af-fected (see also thermodynamics). The second law ofthermodynamics describes why a catalyst does not change

3the chemical equilibrium of a reaction. Suppose therewas such a catalyst that shifted an equilibrium. Intro-ducing the catalyst to the system would result in a reac-tion to move to the new equilibrium, producing energy.Production of energy is a necessary result since reactionsare spontaneous if and only if Gibbs free energy is pro-duced, and if there is no energy barrier, there is no needfor a catalyst. Then, removing the catalyst would also re-sult in reaction, producing energy; i.e. the addition andits reverse process, removal, would both produce energy.Thus, a catalyst that could change the equilibrium wouldbe a perpetual motion machine, a contradiction to thelaws of thermodynamics.[9]

If a catalyst does change the equilibrium, then it must beconsumed as the reaction proceeds, and thus it is also areactant. Illustrative is the base-catalysed hydrolysis ofesters, where the produced carboxylic acid immediatelyreacts with the base catalyst and thus the reaction equi-librium is shifted towards hydrolysis.The SI derived unit for measuring the catalytic activityof a catalyst is the katal, which is moles per second. Theproductivity of a catalyst can be described by the turn overnumber (or TON) and the catalytic activity by the turnover frequency (TOF), which is the TON per time unit.The biochemical equivalent is the enzyme unit. For moreinformation on the eciency of enzymatic catalysis, seethe article on Enzymes.The catalyst stabilizes the transition state more than it sta-bilizes the starting material. It decreases the kinetic bar-rier by decreasing the dierence in energy between start-ing material and transition state. It does not change theenergy dierence between starting materials and prod-ucts (thermodynamic barrier), or the available energy(this is provided by the environment as heat or light).

3.4 MaterialsThe chemical nature of catalysts is as diverse as catal-ysis itself, although some generalizations can be made.Proton acids are probably the most widely used catalysts,especially for the many reactions involving water, includ-ing hydrolysis and its reverse. Multifunctional solids of-ten are catalytically active, e.g. zeolites, alumina, higher-order oxides, graphitic carbon, nanoparticles, nanodots,and facets of bulk materials. Transition metals are of-ten used to catalyze redox reactions (oxidation, hydro-genation). Examples are nickel, such as Raney nickel forhydrogenation, and vanadium(V) oxide for oxidation ofsulfur dioxide into sulfur trioxide by the so-called contactprocess. Many catalytic processes, especially those usedin organic synthesis, require late transition metals, suchas palladium, platinum, gold, ruthenium, rhodium, oriridium.Some so-called catalysts are really precatalysts. Pre-catalysts convert to catalysts in the reaction. For exam-ple, Wilkinsons catalyst RhCl(PPh3)3 loses one triph-

enylphosphine ligand before entering the true catalyticcycle. Precatalysts are easier to store but are easily ac-tivated in situ. Because of this preactivation step, manycatalytic reactions involve an induction period.Chemical species that improve catalytic activity are calledco-catalysts (cocatalysts) or promotors in cooperativecatalysis.

4 TypesCatalysts can be heterogeneous or homogeneous, depend-ing on whether a catalyst exists in the same phase as thesubstrate. Biocatalysts (enzymes) are often seen as a sep-arate group.

4.1 Heterogeneous catalystsMain article: Heterogeneous catalysisHeterogeneous catalysts act in a dierent phase than the

The microporous molecular structure of the zeolite ZSM-5 is ex-ploited in catalysts used in reneries

reactants. Most heterogeneous catalysts are solids that acton substrates in a liquid or gaseous reaction mixture. Di-verse mechanisms for reactions on surfaces are known,depending on how the adsorption takes place (Langmuir-Hinshelwood, Eley-Rideal, and Mars-van Krevelen).[10]The total surface area of solid has an important eect onthe reaction rate. The smaller the catalyst particle size,the larger the surface area for a given mass of particles.A heterogeneous catalyst has active sites, which are theatoms or crystal faces where the reaction actually occurs.Depending on the mechanism, the active site may be ei-ther a planar exposed metal surface, a crystal edge with

4 4 TYPES

Zeolites are extruded as pellets for easy handling in catalytic re-actors.

imperfect metal valence or a complicated combination ofthe two. Thus, not only most of the volume, but also mostof the surface of a heterogeneous catalyst may be catalyt-ically inactive. Finding out the nature of the active siterequires technically challenging research. Thus, empiri-cal research for nding out new metal combinations forcatalysis continues.For example, in the Haber process, nely divided ironserves as a catalyst for the synthesis of ammonia fromnitrogen and hydrogen. The reacting gases adsorb ontoactive sites on the iron particles. Once physically ad-sorbed, the reagents undergo chemisorption that results indissociation into adsorbed atomic species, and new bondsbetween the resulting fragments form in part due to theirclose proximity. In this way the particularly strong triplebond in nitrogen is broken, which would be extremely un-common in the gas phase due to its high activation en-ergy. Thus, the activation energy of the overall reactionis lowered, and the rate of reaction increases. Anotherplace where a heterogeneous catalyst is applied is in theoxidation of sulfur dioxide on vanadium(V) oxide for theproduction of sulfuric acid.Heterogeneous catalysts are typically "supported, whichmeans that the catalyst is dispersed on a second mate-rial that enhances the eectiveness or minimizes theircost. Supports prevent or reduce agglomeration and sin-tering of the small catalyst particles, exposing more sur-face area, thus catalysts have a higher specic activity (pergram) on a support. Sometimes the support is merely asurface on which the catalyst is spread to increase thesurface area. More often, the support and the catalystinteract, aecting the catalytic reaction. Supports areporous materials with a high surface area, most com-monly alumina, zeolites or various kinds of activatedcarbon. Specialized supports include silicon dioxide,titanium dioxide, calcium carbonate, and barium sulfate.

4.1.1 Electrocatalysts

Main article: Electrocatalyst

In the context of electrochemistry, specically in fuel cellengineering, various metal-containing catalysts are usedto enhance the rates of the half reactions that comprisethe fuel cell. One common type of fuel cell electrocata-lyst is based upon nanoparticles of platinum that are sup-ported on slightly larger carbon particles. When in con-tact with one of the electrodes in a fuel cell, this platinumincreases the rate of oxygen reduction either to water, orto hydroxide or hydrogen peroxide.

4.2 Homogeneous catalysts

Main article: Homogeneous catalysis

Homogeneous catalysts function in the same phase asthe reactants, but the mechanistic principles invoked inheterogeneous catalysis are generally applicable. Typ-ically homogeneous catalysts are dissolved in a solventwith the substrates. One example of homogeneous catal-ysis involves the inuence of H+ on the esterication ofcarboxylic acids, such as the formation of methyl ac-etate from acetic acid and methanol.[11] For inorganicchemists, homogeneous catalysis is often synonymouswith organometallic catalysts.[12]

4.2.1 Organocatalysis

Main article: Organocatalysis

Whereas transition metals sometimes attract most of theattention in the study of catalysis, small organic moleculeswithout metals can also exhibit catalytic properties, as isapparent from the fact that many enzymes lack transi-tion metals. Typically, organic catalysts require a higherloading (amount of catalyst per unit amount of reactant,expressed in mol% amount of substance) than transitionmetal(-ion)-based catalysts, but these catalysts are usu-ally commercially available in bulk, helping to reducecosts. In the early 2000s, these organocatalysts were con-sidered new generation and are competitive to tradi-tional metal(-ion)-containing catalysts. Organocatalystsare supposed to operate akin to metal-free enzymes uti-lizing, e.g., non-covalent interactions such as hydrogenbonding. The discipline organocatalysis is divided in theapplication of covalent (e.g., proline, DMAP) and non-covalent (e.g., thiourea organocatalysis) organocatalystsreferring to the preferred catalyst-substrate binding andinteraction, respectively.

5.2 Bulk chemicals 5

4.3 Enzymes and biocatalysts

In biology, enzymes are protein-based catalysts inmetabolism and catabolism. Most biocatalysts areenzymes, but other non-protein-based classes ofbiomolecules also exhibit catalytic properties includingribozymes, and synthetic deoxyribozymes.[13]

Biocatalysts can be thought of as intermediate be-tween homogeneous and heterogeneous catalysts, al-though strictly speaking soluble enzymes are homoge-neous catalysts and membrane-bound enzymes are het-erogeneous. Several factors aect the activity of enzymes(and other catalysts) including temperature, pH, concen-tration of enzyme, substrate, and products. A particularlyimportant reagent in enzymatic reactions is water, whichis the product of many bond-forming reactions and a re-actant in many bond-breaking processes.In biocatalysis, enzymes are employed to prepare manycommodity chemicals including high-fructose corn syrupand acrylamide.Some monoclonal antibodies whose binding target isa stable molecule which resembles the transition stateof a chemical reaction can function as weak catalystsfor that chemical reaction by lowering its activationenergy.[14] Such catalytic antibodies are sometimes called"abzymes".

5 Signicance

Left: Partially caramelised cube sugar, Right: burning cube sugarwith ash as catalyst

Estimates are that 90% of all commercially producedchemical products involve catalysts at some stage inthe process of their manufacture.[15] In 2005, cat-alytic processes generated about $900 billion in productsworldwide.[16] Catalysis is so pervasive that subareas arenot readily classied. Some areas of particular concen-tration are surveyed below.

5.1 Energy processing

Petroleum rening makes intensive use of catalysisfor alkylation, catalytic cracking (breaking long-chainhydrocarbons into smaller pieces), naphtha reformingand steam reforming (conversion of hydrocarbons into

synthesis gas). Even the exhaust from the burning of fos-sil fuels is treated via catalysis: Catalytic converters, typ-ically composed of platinum and rhodium, break downsome of the more harmful byproducts of automobile ex-haust.

2 CO + 2 NO 2 CO2 + N2

With regard to synthetic fuels, an old but still importantprocess is the Fischer-Tropsch synthesis of hydrocarbonsfrom synthesis gas, which itself is processed via water-gas shift reactions, catalysed by iron. Biodiesel and re-lated biofuels require processing via both inorganic andbiocatalysts.Fuel cells rely on catalysts for both the anodic and ca-thodic reactions.Catalytic heaters generate ameless heat from a supply ofcombustible fuel.

5.2 Bulk chemicals

Some of the largest-scale chemicals are produced viacatalytic oxidation, often using oxygen. Examples in-clude nitric acid (from ammonia), sulfuric acid (fromsulfur dioxide to sulfur trioxide by the chamber process),terephthalic acid from p-xylene, and acrylonitrile frompropane and ammonia.Many other chemical products are generated by large-scale reduction, often via hydrogenation. The largest-scale example is ammonia, which is prepared via theHaber process from nitrogen. Methanol is prepared fromcarbon monoxide.Bulk polymers derived from ethylene and propylene areoften prepared via Ziegler-Natta catalysis. Polyesters,polyamides, and isocyanates are derived via acid-basecatalysis.Most carbonylation processes require metal catalysts, ex-amples include the Monsanto acetic acid process andhydroformylation.

5.3 Fine chemicals

Many ne chemicals are prepared via catalysis; methodsinclude those of heavy industry as well as more special-ized processes that would be prohibitively expensive ona large scale. Examples include olen metathesis usingGrubbs catalyst, the Heck reaction, and Friedel-Craftsreactions.Because most bioactive compounds are chiral, manypharmaceuticals are produced by enantioselective cataly-sis (catalytic asymmetric synthesis).

6 9 SEE ALSO

5.4 Food processingOne of the most obvious applications of catalysis is thehydrogenation (reaction with hydrogen gas) of fats us-ing nickel catalyst to produce margarine.[17] Many otherfoodstus are prepared via biocatalysis (see below).

5.5 EnvironmentCatalysis impacts the environment by increasing the ef-ciency of industrial processes, but catalysis also playsa direct role in the environment. A notable example isthe catalytic role of chlorine free radicals in the break-down of ozone. These radicals are formed by the actionof ultraviolet radiation on chlorouorocarbons (CFCs).

Cl + O3 ClO + O2ClO + O Cl + O2

6 HistoryIn a general sense,[18] anything that increases the rateof a process is a catalyst, a term derived from Greek, meaning to annul, or to untie, or topick up. The term catalysis was coined by Jns JakobBerzelius in 1835[19] to describe reactions that are accel-erated by substances that remain unchanged after the re-action. Other early chemists involved in catalysis wereEilhardMitscherlich[20] who referred to contact processesand Johann Wolfgang Dbereiner[21] who spoke of con-tact action and whose lighter based on hydrogen and aplatinum sponge became a huge commercial success inthe 1820s. Humphry Davy discovered the use of plat-inum in catalysis.[22] In the 1880s, Wilhelm Ostwald atLeipzig University started a systematic investigation intoreactions that were catalyzed by the presence of acids andbases, and found that chemical reactions occur at niterates and that these rates can be used to determine thestrengths of acids and bases. For this work, Ostwald wasawarded the 1909 Nobel Prize in Chemistry.[23]

7 Inhibitors, poisons and promot-ers

Substances that reduce the action of catalysts are calledcatalyst inhibitors if reversible, and catalyst poisons if ir-reversible. Promoters are substances that increase thecatalytic activity, even though they are not catalysts bythemselves.Inhibitors are sometimes referred to as negative cata-lysts since they decrease the reaction rate.[24] Howeverthe term inhibitor is preferred since they do not work byintroducing a reaction path with higher activation energy;

this would not reduce the rate since the reaction wouldcontinue to occur by the non-catalyzed path. Instead theyact either by deactivating catalysts, or by removing reac-tion intermediates such as free radicals.[24][25]

The inhibitor may modify selectivity in addition to rate.For instance, in the reduction of acetylene to ethylene,a palladium (Pd) catalyst partly poisoned with lead(II)acetate (Pb(CH3COO)2) can be used. Without the deac-tivation of the catalyst, the ethene produced will be fur-ther reduced to ethane.[26][27]

The inhibitor can produce this eect by, e.g., selectivelypoisoning only certain types of active sites. Anothermechanism is the modication of surface geometry. Forinstance, in hydrogenation operations, large planes ofmetal surface function as sites of hydrogenolysis catal-ysis while sites catalyzing hydrogenation of unsaturatesare smaller. Thus, a poison that covers surface randomlywill tend to reduce the number of uncontaminated largeplanes but leave proportionally more smaller sites free,thus changing the hydrogenation vs. hydrogenolysis se-lectivity. Many other mechanisms are also possible.Promoters can cover up surface to prevent production of amat of coke, or even actively remove such material (e.g.,rhenium on platinum in platforming). They can aid thedispersion of the catalytic material or bind to reagents.

8 Current marketThe global demand on catalysts in 2010 was estimated atapproximately 29.5 billionsUSD.With the rapid recoveryin automotive and chemical industry overall, the globalcatalyst market is expected to experience fast growth inthe next years.[28]

9 See also Chemical reaction

Substrate Reagent Catalyst Enzyme Product

Abzyme Autocatalysis BIG-NSE (Berlin Graduate School of Natural Sci-ences and Engineering)

Catalysis Science & Technology (a chemistry jour-nal)

Environmental triggers

7 Enzyme catalysis Industrial catalysts Kelvin probe force microscope Limiting reagent Pharmaceutic adjuvant Phase Boundary Catalysis Phase transfer catalyst Photocatalysis Ribozyme (RNA biocatalyst) SUMO enzymes Temperature-programmed reduction Thermal desorption spectroscopy

10 References IUPAC, Compendium of Chemical Terminology,2nd ed. (the Gold Book) (1997). Online correctedversion: (2006) "catalyst".

[1] http://goldbook.iupac.org/C00876.html

[2] 7 things you may not know about catalysis Louise Lerner,Argonne National Laboratory (2011)

[3] The 12 Principles of Green Chemistry. United StatesEnvironmental Protection Agency. Retrieved 2012-04-30.

[4] Genie in a Bottle. University of Minnesota. 2005-03-02.

[5] Richard I. Masel Chemical Kinetics and CatalysisWiley-Interscience, New York, 2001. ISBN 0-471-24197-0.

[6] Dybkaer, R. (2001). UNIT KATAL FORCATALYTIC ACTIVITY (IUPAC Techni-cal Report)". Pure Appl. Chem. 73 (6): 929.doi:10.1351/pac200173060927.

[7] Jacoby, Mitch (16 February 2009). Making Water Stepby Step. Chemical & Engineering News. p. 10.

[8] Matthiesen J, Wendt S, Hansen J, Madsen GK, LiraE, Galliker P, Vestergaard EK, Schaub R, Laegsgaard E,Hammer B, Besenbacher F; Wendt; Madsen; Lira; Gal-liker; Vestergaard; Schaub; Laegsgaard; Hammer; Be-senbacher (2009). Observation of All the IntermediateSteps of a Chemical Reaction on an Oxide Surface byScanning Tunneling Microscopy. ACS Nano 3 (3): 517526. doi:10.1021/nn8008245. ISSN 1520-605X. PMID19309169. Missing |last3= in Authors list (help)

[9] A.J.B. Robertson Catalysis of Gas Reactions by Metals.Logos Press, London, 1970.

[10] Helmut Knzinger, Karl Kochloe Heterogeneous Catal-ysis and Solid Catalysts in Ullmanns Encyclopediaof Industrial Chemistry 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a05_313. Article Online PostingDate: January 15, 2003

[11] Arno Behr Organometallic Compounds and Ho-mogeneous Catalysis Ullmanns Encyclopedia ofIndustrial Chemistry, 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a18_215. Article Online PostingDate: June 15, 2000

[12] C. Elschenbroich, Organometallics (2006) Wiley-VCH:Weinheim. ISBN 978-3-527-29390-2

[13] D. L. Nelson and M. M. Cox Lehninger, Principles of Bio-chemistry 3rd Ed. Worth Publishing: New York, 2000.ISBN 1-57259-153-6.

[14] http://www.documentroot.com/2010/03/catalytic-antibodies-simply-explained.html

[15] Recognizing the Best in Innovation: Breakthrough Cata-lyst. R&D Magazine, September 2005, p. 20.

[16] 1.4.3 INDUSTRIAL PROCESS EFFICIENCY. cli-matetechnology.gov

[17] Types of catalysis. Chemguide. Retrieved 2008-07-09.[18] Brd Lindstrm and Lars J. Petterson (2003) A brief his-

tory of catalysis, Cattech, 7 (4) : 130-138. Available on-line at: ScienceNet.

[19] J. J. Berzelius, rsberttelsen om framsteg i fysik och kemi[Annual report on progress in physics and chemistry],(Stockholm, Sweden: Royal Swedish Academy of Sci-ences, 1835). After reviewing Eilhard Mitscherlichs re-search on the formation of ether, Berzelius coins the wordkatalys (catalysis) on page 245:

Original: Jag skall derfre, fr att be-gagna en i kemien vlknd hrledning, kalladen kroppars katalytiska kraft, snderdelninggenom denna kraft katalys, likasom vi med or-det analys beteckna tskiljandet af kropparsbestndsdelar medelst den vanliga kemiskafrndskapen.

Translation: I shall, therefore, to em-ploy a well-known derivation in chemistry,call [the catalytic] bodies [i.e., substances]the catalytic force and the decomposition of[other] bodies by this force catalysis, just aswe signify by the word analysis the separa-tion of the constituents of bodies by the usualchemical anities.

[20] E.Mitscherlich (1834) Ueber die Aetherbildung (On theformation of ether), Annalen der Physik und Chemie, 31(18) : 273-282.

[21] See: Dbereiner (1822) Glhendes Verbrennen des

Alkohols durch verschiedene erhitzte Metalle undMetalloxyde (Incandescent burning of alcohol byvarious heated metals and metal oxides), Journalfr Chemie und Physik, 34 : 91-92.

8 11 EXTERNAL LINKS

Dbereiner (1823) Neu entdeckte merkwrdigeEigenschaften des Platinsuboxyds, des oxydirtenSchwefel-Platins und des metallischen Platin-staubes (Newly discovered remarkable propertiesof platinum suboxide, oxidized platinum sulde andmetallic platinum dust), Journal fr Chemie undPhysik, 38 : 321-326.

[22] Sir Humphry Davy (1817) Some new experiments andobservations on the combustion of gaseous mixtures, withan account of a method of preserving a continued lightin mixtures of inammable gases and air without ame,Philosophical Transactions of the Royal Society of Lon-don, 107 : 77-85.

[23] M.W. Roberts (2000). Birth of the catalytic con-cept (18001900)". Catalysis Letters 67 (1): 14.doi:10.1023/A:1016622806065.

[24] K.J. Laidler Physical Chemistry with Biological Applica-tions, Benjamin/Cummings 1978, pp. 415417

[25] K.J. Laidler and J.H. Meiser, Physical Chemistry, Ben-jamin/Cummings (1982), p. 425

[26] W.P. Jencks, Catalysis in Chemistry and EnzymologyMcGraw-Hill, New York, 1969. ISBN 0-07-032305-4

[27] Myron L Bender, Makoto Komiyama, Raymond J Berg-eron The Bioorganic Chemistry of Enzymatic CatalysisWiley-Interscience, Hoboken, U.S., 1984 ISBN 0-471-05991-9

[28] Market Report: Global Catalyst Market, 2nd Edition.Acmite Market Intelligence.

11 External links Science Aid: Catalysts Page for high school levelscience

W.A. Herrmann Technische Universitt presenta-tion

Alumite Catalyst, Kameyama-Sakurai Laboratory,Japan

Inorganic Chemistry and Catalysis Group, UtrechtUniversity, The Netherlands

Centre for Surface Chemistry and Catalysis Carbons & Catalysts Group, University of Concep-cion, Chile

Center for Enabling New Technologies ThroughCatalysis, An NSF Center for Chemical Innovation,USA

Bubbles turn on chemical catalysts, Science Newsmagazine online, April 6, 2009.

912 Text and image sources, contributors, and licenses12.1 Text

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Technical perspectiveBackgroundGeneral principlesUnitsTypical mechanismReaction energeticsMaterials

TypesHeterogeneous catalystsElectrocatalysts

Homogeneous catalystsOrganocatalysis

Enzymes and biocatalysts

SignificanceEnergy processingBulk chemicalsFine chemicalsFood processingEnvironment

HistoryInhibitors, poisons and promotersCurrent marketSee alsoReferencesExternal linksText and image sources, contributors, and licensesTextImagesContent license