Editing Propylene oxide (section)

==Production==
Industrial production of propylene oxide starts from [[propylene]].<ref>{{cite journal | vauthors = Nijhuis TA, Makkee M, Moulijn JA, Weckhuysen BM |doi=10.1021/ie0513090|title=The Production of Propene Oxide: Catalytic Processes and Recent Developments|year=2006 |journal=Industrial & Engineering Chemistry Research|volume=45|issue=10|pages=3447–3459|hdl=1874/20149|hdl-access=free}}</ref> Two general approaches are employed, one involving [[Halohydrin#Synthesis|chlorohydrin formation]] and the other involving [[Redox|oxidation]].<ref name=PO>{{Ullmann| vauthors = Kahlich D, Wiechern U, Lindner J |date=2002|title=Propylene Oxide|doi=10.1002/14356007.a22_239}}</ref> In 2005, about half of the world production was through [[chlorohydrin]] technology and one half via oxidation routes. The latter approach is growing in importance.<ref name= Nijhuis>{{cite journal| vauthors = Nijhuis TA, Makkee M, Moulijn JA, Weckhuysen BM  |title=The Production of Propene Oxide: Catalytic Processes and Recent Developments|journal=Industrial & Engineering Chemistry Research |volume=45 |issue=10 |pages=3447–3459 |doi=10.1021/ie0513090 |year=2006 |hdl=1874/20149 |hdl-access=free}}</ref>

===Chlorohydrin route===
The traditional route proceeds via the conversion of [[propene|propylene]] to [[propylene chlorohydrin]] according to the following simplified scheme:

:[[File:Propylenoxid Darstellung 1.svg|450px]]

The mixture of 1-chloro-2-propanol and 2-chloro-1-propanol then undergoes [[Williamson ether synthesis|internal cyclization]]. For example:

:[[File:Propylenoxid Darstellung 2.svg|330px]]

[[Lime (mineral)|Lime]] ([[calcium hydroxide]]) is often used to absorb the [[HCl]].

===Oxidation of propylene===
The other general route to propylene oxide involves oxidation of propylene with an [[Organic peroxides|organic peroxide]]. The reaction follows this stoichiometry:

:CH<sub>3</sub>CH=CH<sub>2</sub>  +  RO<sub>2</sub>H  →   CH<sub>3</sub>CHCH<sub>2</sub>O  +  ROH

The process is practiced with four [[hydroperoxide]]s:<ref name= Nijhuis/>
*In the [[Halcon process]], [[tert-Butyl hydroperoxide|''t''-Butyl hydroperoxide]] derived from oxygenation of [[isobutane]], which affords [[Tert-Butanol|''t''-butanol]].  This coproduct can be dehydrated to isobutene, converted to [[MTBE]], an additive for [[gasoline]].
* [[Ethylbenzene hydroperoxide]], derived from oxygenation of [[ethylbenzene]], which affords 1-phenylethanol.  This coproduct can be dehydrated to give [[styrene]], a useful monomer.
*[[Cumene hydroperoxide]] derived from oxygenation of [[cumene]] (isopropylbenzene), which affords [[cumyl alcohol]]. Via [[dehydration reaction|dehydration]] and [[hydrogenation]] this coproduct can be recycled back to cumene.  This technology was commercialized by Sumitomo Chemical.<ref>{{cite web|url=http://nexant.ecnext.com/coms2/gi_0255-227/Developments-in-Propylene-Oxide-Technology.html|title=Summary of Sumitomo process from Nexant Reports|access-date=2007-09-18|url-status=dead|archive-url=https://archive.today/20060117092104/http://nexant.ecnext.com/coms2/gi_0255-227/Developments-in-Propylene-Oxide-Technology.html|archive-date=2006-01-17}}</ref>
*[[Hydrogen peroxide]] is the oxidant in the hydrogen peroxide to propylene oxide (HPPO) process, catalyzed by a titanium-doped [[silicalite]]:
*:C<sub>3</sub>H<sub>6</sub> + H<sub>2</sub>O<sub>2</sub> → C<sub>3</sub>H<sub>6</sub>O + H<sub>2</sub>O

In principle, this process produces only [[water]] as a [[By-product|side product]].  In practice, some ring-opened derivatives of PO are generated.<ref>{{cite journal | vauthors = Russo V, Tesser R, Santacesaria E, Di Serio M |title=Chemical and Technical Aspects of Propene Oxide Production via Hydrogen Peroxide (HPPO Process)|journal=Industrial & Engineering Chemistry Research |year=2013|volume=52|issue=3|pages=1168–1178|doi=10.1021/ie3023862}}</ref>

Propylene oxide is chiral building block that is commercially available in either enantiomeric form ((''R'')-(+) and (''S'')-(–)).  The separated enantiomers can be obtained through a Co(III)-salen-catalyzed hydrolytic [[kinetic resolution]] of the racemic material.<ref>{{Cite journal |last1=Schaus |first1=Scott E. |last2=Brandes |first2=Bridget D. |last3=Larrow |first3=Jay F. |last4=Tokunaga |first4=Makoto |last5=Hansen |first5=Karl B. |last6=Gould |first6=Alexandra E. |last7=Furrow |first7=Michael E. |last8=Jacobsen |first8=Eric N. |date=2002-02-01 |title=Highly Selective Hydrolytic Kinetic Resolution of Terminal Epoxides Catalyzed by Chiral (salen)Co III Complexes. Practical Synthesis of Enantioenriched Terminal Epoxides and 1,2-Diols |url=https://pubs.acs.org/doi/10.1021/ja016737l |journal=Journal of the American Chemical Society |language=en |volume=124 |issue=7 |pages=1307–1315 |doi=10.1021/ja016737l |pmid=11841300 |bibcode=2002JAChS.124.1307S |issn=0002-7863|url-access=subscription }}</ref>