Tripropylene, also known as propylene trimer, is usually sold as a mixture of
structural isomers of
nonene
Nonene is an alkene with the molecular formula C9H18. Many structural isomers are possible, depending on the location of the C=C double bond and the branching of the other parts of the molecule. Industrially, the most important nonenes are trimers ...
. This mixture is obtained by
oligomerization
In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relativ ...
of
propene
Propylene, also known as propene, is an unsaturated organic compound with the chemical formula CH3CH=CH2. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petro ...
:
:C
3H
6 → C
9H
18
In this process, two double bonds are lost and one is retained as illustrated by the isomer shown in the figure. The reaction is catalyzed by acids, such as
polyphosphoric acid
A phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is bonded to four oxygen (O) atoms, one of them through a double bond, arranged as the corners of a tetrahedron. ...
. A variety of catalysts have been explored.
[Johan A. Martens, Wim H. Verrelst, Georges M. Mathys, Stephen H. Brown, Pierre A. Jacobs "Tailored Catalytic Propene Trimerization over Acidic Zeolites with Tubular Pores" Angewandte Chemie International Edition Angewandte Chemie International Edition 2005, Volume 44, Issue 35, pages 5687–5690. ] The reaction proceeds via the formation of a carbocation ((CH
3)
2CH
+), which attacks another propylene unit, generating a new carbocation, etc. This kind of process affords mixtures (C
3H
6)
n.
Like other
alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
s, propylene trimer is used as an
alkylating agent
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effectin ...
. A number of
surfactants and
lubricants are produced by alkylation of aromatic substrates.
See also
*
1-Nonene - the linear analogue
References
{{reflist
Alkenes
Trimers (chemistry)