In
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
, the Halcon process refers to technology for the production of
propylene oxide by oxidation of
propylene with
tert-butyl hydroperoxide. The reaction requires metal
catalysts, which typically contain
molybdenum
Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin ''molybdaenum'', which is based on Ancient Greek ', meaning lead, since its ores were confused with lea ...
:
:(CH
3)
3COOH + CH
2=CHCH
3 → (CH
3)
3COH + CH
2OCHCH
3
The byproduct
tert-butanol is recycled or converted to other useful compounds. The process once operated at the scale of >2 billion kg/y.
The lighter analogue of propylene oxide,
ethylene oxide, is produced by silver-catalyzed reaction of
ethylene
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).
Ethylene i ...
with
oxygen. Attempts to implement this relatively simple technology to the conversion of
propylene to
propylene oxide fail. Instead only combustion predominates. The problems are attributed to the sensitivity of
allylic
In organic chemistry, an allyl group is a substituent with the structural formula , where R is the rest of the molecule. It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, . ...
C-H bonds.
Mechanism
The oxidation is thought to proceed by formation of Mo(η
2-O
2-tert-Bu) complexes. The peroxy O center is rendered highly electrophilic, leading to attack on the alkene.
History
The Halcon process was developed by
Halcon International
Halcon or Halcones, may refer to:
People
* Pequeño Halcón (aka Rogelio Espinoza López), Mexican masked wrestler
* Super Halcón Jr. (born 1987), Mexican masked wrestler
* El Halcón (born 1947, as José Luis Melchor Ortiz), Mexican masked wre ...
.
[{{cite journal , doi=10.1021/cen-v059n007.p016, title=Ralph Landau wins 1981 Perkin Medal, year=1981, last1=Fallwell, first1=William, journal=Chemical & Engineering News Archive, volume=59, issue=7, page=16]
References
Catalysis