organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

, ethenolysis is a chemical process in which internal

olefin In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as α-olefins. The International Union of Pu ...

s are degraded using

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 bond, carbon–carbon doub ...

() as the

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

. The reaction is an example of cross metathesis. The utility of the reaction is driven by the low cost of ethylene as a reagent and its selectivity. It produces compounds with terminal alkene

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s (α-olefins), which are more amenable to other reactions such as

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many fo ...

and

hydroformylation In organic chemistry, hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes () from alkenes (). This chemical reaction entails the net addition of a formyl group () and a hydrogen ...

. The general reaction equation is: :

\ce +  \longrightarrow \ce + \ce

Ethenolysis is a form of methylenation, i.e., the installation of methylene () groups.

Applications

Terminal alkenes

Using ethenolysis, higher molecular weight internal

alkenes In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

can be converted to more valuable terminal alkenes. The

Shell higher olefin process The Shell higher olefin process (SHOP) is a chemical process for the production of linear alpha olefins via ethylene oligomerization and olefin metathesis invented and exploited by Shell plc.''Industrial Organic Chemistry'', Klaus Weissermel, Hans ...

(SHOP process) uses ethenolysis on an industrial scale. SHOP α-olefin mixtures are first separated by distillation. Higher molecular weight fractions are isomerized by

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

alumina Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly ...

catalysts in the liquid phase. The resulting internal olefins are reacted with ethylene to regenerate α-olefins. The large excess of ethylene moves the reaction equilibrium to the terminal α-olefins. Catalysts are often prepared from

rhenium(VII) oxide Rhenium(VII) oxide is the inorganic compound with the formula Rhenium, Re2oxide, O7. This yellowish solid is the anhydride of HOReO3. Perrhenic acid, Re2O7·2H2O, is closely related to Re2O7. Re2O7 is the raw material for all rhenium compounds, b ...

() supported on

Perfume

In one application, neohexene, a precursor to perfumes, is prepared by ethenolysis of

diisobutene Diisobutene (also known as Diisobutylene and Isooctene) refers to a pair of organic compounds with the overall formula C8H16. The isomers have the same carbon skeleton but differ in the location of the C=C bond. Both are colorless liquids with ver ...

: :

\overset +  \longrightarrow \overset +  \ce

α,ω-Dienes, i.e., diolefins of the formula , are prepared industrially by ethenolysis of cyclic alkenes. For example, 1,5-hexadiene, a useful crosslinking agent and synthetic intermediate, is produced from

1,5-cyclooctadiene 1,5-Cyclooctadiene (also known as cycloocta-1,5-diene) is a cyclic compound, cyclic hydrocarbon with the chemical formula , specifically . There are three configurational isomers with this structure, that differ by the arrangement of the four C� ...

: :

\ce + 2 \longrightarrow  \ce\ce

The catalyst is derived from

supported on

. 1,9-Decadiene, a related species, is produced similarly from cyclooctene.

Decenoic acid

In an application directed at using renewable feedstocks, methyl oleate, derived from natural seed oils, can be converted to

1-decene Decene is an organic compound with the chemical formula . Decene contains a chain of ten carbon atoms with one double bond, making it an alkene. There are many isomers of decene depending on the position and geometry of the double bond. Dec-1- ...

and methyl 9- decenoate: :

\ce  +    \longrightarrow \ce  +  \ce

Polyethylene and polypropylene recycling

Mixed polyolefins can be recycled via high selectivity isomerizing ethenolysation using a sodium on alumina catalyst followed by olefin metathesis using a stream of

gas flowing into a reaction chamber containing a

tungsten oxide Tungsten has several oxidation states, and therefore oxides: * Tungsten(III) oxide * Tungsten(IV) oxide, also known as tungsten dioxide * Tungsten(VI) oxide, also known as tungsten trioxide * Tungsten pentoxide {{Short pages monitor