Editing Catalysis (section)

==Significance==
[[File:Verbrennung eines Zuckerwürfels.png|thumb|Left: Partially caramelized [[cube sugar]], Right: burning cube sugar with ash as catalyst]]
[[File:TiCrPt micropump3.webm|thumb|A Ti-Cr-Pt tube (~40 μm long) releases oxygen bubbles when immersed in [[hydrogen peroxide]] (via catalytic decomposition), forming a [[micropump]].<ref>{{cite journal |title=Tunable catalytic tubular micro-pumps operating at low concentrations of hydrogen peroxide |journal=Physical Chemistry Chemical Physics |volume=13 |issue=21 |pages=10131–35 |year=2011 |last1=Solovev |first1=Alexander A. |last2=Sanchez |first2=Samuel |last3=Mei |first3=Yongfeng |last4=Schmidt |first4=Oliver G. |bibcode=2011PCCP...1310131S |pmid=21505711 |doi=10.1039/C1CP20542K |url=http://nanomem.fudan.edu.cn/79solovev2011.pdf |url-status=dead |archive-url=https://web.archive.org/web/20190328131026/http://nanomem.fudan.edu.cn/79solovev2011.pdf |archive-date=2019-03-28}}</ref>]]

Estimates are that 90% of all commercially produced chemical products involve catalysts at some stage in the process of their manufacture. In 2005, catalytic processes generated about $900 billion in products worldwide.<ref>[http://www.climatetechnology.gov/library/2005/tech-options/tor2005-143.pdf 1.4.3 Industrial Process Efficiency] {{webarchive|url=https://web.archive.org/web/20080517071700/http://www.climatetechnology.gov/library/2005/tech-options/tor2005-143.pdf |date=2008-05-17}}. climatetechnology.gov</ref> Catalysis is so pervasive that subareas are not readily classified. Some areas of particular concentration are surveyed below.

===Energy processing===
[[Petroleum]] refining makes intensive use of catalysis for [[alkylation]], [[catalytic cracking]] (breaking long-chain hydrocarbons into smaller pieces), [[petroleum naphtha|naphtha]] reforming and [[steam reforming]] (conversion of [[hydrocarbon]]s into [[synthesis gas]]). Even the exhaust from the burning of fossil fuels is treated via catalysis: [[Catalytic converter]]s, typically composed of [[platinum]] and [[rhodium]], break down some of the more harmful byproducts of automobile exhaust.
:2 CO + 2 NO → 2 CO{{sub|2}} + N{{sub|2}}

With regard to synthetic fuels, an old but still important process is the [[Fischer–Tropsch synthesis]] of hydrocarbons from [[synthesis gas]], which itself is processed via [[water gas shift reaction|water-gas shift reactions]], catalyzed by iron. The [[Sabatier reaction]] produces [[methane]] from carbon dioxide and hydrogen. [[Biodiesel]] and related biofuels require processing via both inorganic and biocatalysts.

[[Fuel cell]]s rely on catalysts for both the anodic and cathodic reactions.

[[Catalytic heater]]s generate flameless heat from a supply of combustible fuel.

===Bulk chemicals===
[[File:CataylstExampleSulfuricAcidPlant.jpg|alt=Typical vanadium pentoxide catalyst used in sulfuric acid production for an intermediate reaction to convert sulfur dioxide to sulfur trioxide.|thumb|Typical vanadium pentoxide catalyst used in sulfuric acid production for an intermediate reaction to convert sulfur dioxide to sulfur trioxide.]]
Some of the largest-scale chemicals are produced via catalytic oxidation, often using [[oxygen]]. Examples include [[nitric acid]] (from ammonia), [[sulfuric acid]] (from [[sulfur dioxide]] to [[sulfur trioxide]] by the [[contact process]]), [[terephthalic acid]] from p-xylene, [[acrylic acid]] from [[propylene]] or [[propane]] and [[acrylonitrile]] from propane and ammonia.<ref name="doi"/>

The production of ammonia is one of the largest-scale and most energy-intensive processes. In the [[Haber process]] [[nitrogen]] is combined with hydrogen over an iron oxide catalyst.<ref name=Smil_2004_Enriching>{{cite book |last1=Smil |first1=Vaclav |title=Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production |date=2004 |publisher=MIT |location=Cambridge, MA |isbn=9780262693134 |edition=1st}}</ref> [[Methanol]] is prepared from [[carbon monoxide]] or carbon dioxide but using copper-zinc catalysts.

Bulk polymers derived from [[ethylene]] and [[propylene]] are often prepared using [[Ziegler–Natta catalyst]]. Polyesters, polyamides, and [[isocyanate]]s are derived via [[acid–base catalysis]].

Most [[carbonylation]] processes require metal catalysts, examples include the [[Monsanto acetic acid process]] and [[hydroformylation]].

===Fine chemicals===
Many [[fine chemicals]] are prepared via catalysis; methods include those of heavy industry as well as more specialized processes that would be prohibitively expensive on a large scale. Examples include the [[Heck reaction]], and [[Friedel–Crafts reaction]]s. Because most bioactive compounds are [[chirality (chemistry)|chiral]], many pharmaceuticals are produced by enantioselective catalysis (catalytic [[asymmetric synthesis]]). (R)-1,2-Propandiol, the precursor to the antibacterial [[levofloxacin]], can be synthesized efficiently from hydroxyacetone by using catalysts based on [[BINAP]]-ruthenium complexes, in [[Noyori asymmetric hydrogenation]]:<ref name=Gordon>{{cite journal |title=The role of the metal-bound N–H functionality in Noyori-type molecular catalysts |year=2018 |last1=Dub |first1=Pavel A. |last2=Gordon |first2=John C. |journal=Nature Reviews Chemistry |volume=2 |issue=12 |pages=396–408 |doi=10.1038/s41570-018-0049-z |s2cid=106394152}}</ref>
[[File:levofloxacin3.png|center|632px|levofloxaxin synthesis]]

===Food processing===
One of the most obvious applications of catalysis is the [[hydrogenation]] (reaction with [[hydrogen]] gas) of fats using [[nickel]] catalyst to produce [[margarine]].<ref>{{cite web |publisher=Chemguide |title=Types of catalysis |last=Clark |first=Jim |date=October 2013 |url=https://www.chemguide.co.uk/physical/catalysis/introduction.html}}</ref> Many other foodstuffs are prepared via biocatalysis (see below).

===Environment===
Catalysis affects the environment by increasing the efficiency of industrial processes, but catalysis also plays a direct role in the environment. A notable example is the catalytic role of [[chlorine]] [[free radical]]s in the breakdown of [[ozone]]. These radicals are formed by the action of [[ultraviolet]] [[radiation]] on [[chlorofluorocarbon]]s (CFCs).
:Cl{{sup|'''·'''}} + O{{sub|3}} → ClO{{sup|'''·'''}} + O{{sub|2}}
:ClO{{sup|'''·'''}} + O{{sup|·}} → Cl{{sup|'''·'''}} + O{{sub|2}}