69
4
group –CH 2 –NR 2 (. Fig. 4.7). These amino compounds could be of interest for the synthesis of
new polyamides based on renewable raw materials. HAM is a tandem reaction, i.e. a series of
successive reactions: First, hydroformylation
takes place with the synthesis gas to form the
corresponding aldehyde, which then condenses
with the amine present to form an imine or an
enamine, which is then hydrogenated with excess
hydrogen to form the amine. A catalyst, usually
a rhodium complex, is required for both the
hydroformylation step and the hydrogenation.
Under mild reaction conditions (140 °C, 10 bar
synthesis gas) almost quantitative yields are
achieved. Various amines can be used, e.g. hexylor benzylamine as well as morpholine. Ammonia
is also investigated as an amine component in
more recent work.
Hydrocarboxylation
and Alkoxycarbonylation
Another catalytic reaction with carbon
monoxide is hydrocarboxylation, in which
oleochemicals are converted with CO/water
mixtures. Dicarboxylic acids are formed from
fatty acids, e.g. a branched C19 dicarboxylic acid
from oleic acid (. Fig. 4.7). This reaction, originally discovered by Walter Reppe (BASF) with
nickel catalysts, is now preferably carried out
with cobalt or palladium catalysts. There is also
a metal complex-free variant, the so-called Koch
reaction, which is carried out with strong mineral
acids as catalysts.
Instead of water, the reaction can also be
carried out with alcohols directly leading to the
corresponding esters. This is referred to as alkoxycarbonylation (also known as hydrocarbalkoxylation or hydroesterification). Typical cobalt catalysts
are cobalt carbonyl pyridine systems; a typical
palladium catalyst is, e.g., palladium dichloride/
triphenylphosphine. More recently, the isomerizing
alkoxycarbonylation in particular has been studied
more closely: David J. Cole-Hamilton succeeded in
producing the linear dimethyl 1,19-nonadecanedioate from methyl oleate by methoxycarbonylation
with 95% selectivity (. Fig. 4.9), an interesting
monomer for the production of polyesters.
A palladium complex with the special ligand
bis(di-tertiary-butyl-phosphinomethyl)benzene
was used as catalyst.
The hydroformylation of oleochemicals has
now found its way into industrial applications
with two processes:
5 In the Dow-Chemical process, soybean oil is
used as a raw material. As already explained
in . Table 2.1, soybean oil contains 53%
linoleic acid and 6% linolenic acid, i.e. a
high proportion of fatty acids with several
C=C double bonds. Dow produces polyols from soybean oil in three stages, which
are sold under the trade name RENUVA®.
Initially, the soybean oil is transesterified to
the corresponding methyl esters, followed
by hydroformylation of the multiple double
bonds present in the esters, and finally, the
oligoaldehyde esters formed in this way are
hydrogenated to oligohydroxyl esters, the
RENUVA polyols. These polyols have multiple applications: Diisocyanates are used to
convert them into viscoelastic polyurethanes
(PU), having a high resistance. In the Ford
Mustang, these PUs are used, for example, in
car seats. RENUVA polyols are also used in
the manufacture of flexible elastomers, foams,
adhesives, coatings and sealants.
5 Castor oil is used as the raw material in
the BASF process. Castor oil (7 Sect. 2.2.7)
contains a high proportion of ricinoleic acid,
i.e. a C18:1 acid with an additional hydroxyl
group at the C12 position. BASF uses the
castor oil, i.e. the triglyceride, directly in the
hydroformylation and obtains a new triglyceride containing up to three hydroxyl groups
and three aldehyde functions. Hydrogenation
thus produces a polyol again. In a third step,
this polyol is etherified with ethylene oxide
or propylene oxide to form the final product,
the polyether polyols, which are marketed
under the name Lupranol Balance 35®. These
polyether polyols are used to produce rigid
foams for mattresses.
Both processes have the issue that a broad product spectrum is obtained by functionalization. In
addition, the resulting foams have relatively low
molecular weights.
Closely related to hydroformylation is hydroaminomethylation (HAM), a reaction with
synthesis gas and amines that leads to oleo compounds carrying an additional methylene amino
4.2 · Reactions at the C = C Double Bond of Unsaturated Oleochemicals
4
group –CH 2 –NR 2 (. Fig. 4.7). These amino compounds could be of interest for the synthesis of
new polyamides based on renewable raw materials. HAM is a tandem reaction, i.e. a series of
successive reactions: First, hydroformylation
takes place with the synthesis gas to form the
corresponding aldehyde, which then condenses
with the amine present to form an imine or an
enamine, which is then hydrogenated with excess
hydrogen to form the amine. A catalyst, usually
a rhodium complex, is required for both the
hydroformylation step and the hydrogenation.
Under mild reaction conditions (140 °C, 10 bar
synthesis gas) almost quantitative yields are
achieved. Various amines can be used, e.g. hexylor benzylamine as well as morpholine. Ammonia
is also investigated as an amine component in
more recent work.
Hydrocarboxylation
and Alkoxycarbonylation
Another catalytic reaction with carbon
monoxide is hydrocarboxylation, in which
oleochemicals are converted with CO/water
mixtures. Dicarboxylic acids are formed from
fatty acids, e.g. a branched C19 dicarboxylic acid
from oleic acid (. Fig. 4.7). This reaction, originally discovered by Walter Reppe (BASF) with
nickel catalysts, is now preferably carried out
with cobalt or palladium catalysts. There is also
a metal complex-free variant, the so-called Koch
reaction, which is carried out with strong mineral
acids as catalysts.
Instead of water, the reaction can also be
carried out with alcohols directly leading to the
corresponding esters. This is referred to as alkoxycarbonylation (also known as hydrocarbalkoxylation or hydroesterification). Typical cobalt catalysts
are cobalt carbonyl pyridine systems; a typical
palladium catalyst is, e.g., palladium dichloride/
triphenylphosphine. More recently, the isomerizing
alkoxycarbonylation in particular has been studied
more closely: David J. Cole-Hamilton succeeded in
producing the linear dimethyl 1,19-nonadecanedioate from methyl oleate by methoxycarbonylation
with 95% selectivity (. Fig. 4.9), an interesting
monomer for the production of polyesters.
A palladium complex with the special ligand
bis(di-tertiary-butyl-phosphinomethyl)benzene
was used as catalyst.
The hydroformylation of oleochemicals has
now found its way into industrial applications
with two processes:
5 In the Dow-Chemical process, soybean oil is
used as a raw material. As already explained
in . Table 2.1, soybean oil contains 53%
linoleic acid and 6% linolenic acid, i.e. a
high proportion of fatty acids with several
C=C double bonds. Dow produces polyols from soybean oil in three stages, which
are sold under the trade name RENUVA®.
Initially, the soybean oil is transesterified to
the corresponding methyl esters, followed
by hydroformylation of the multiple double
bonds present in the esters, and finally, the
oligoaldehyde esters formed in this way are
hydrogenated to oligohydroxyl esters, the
RENUVA polyols. These polyols have multiple applications: Diisocyanates are used to
convert them into viscoelastic polyurethanes
(PU), having a high resistance. In the Ford
Mustang, these PUs are used, for example, in
car seats. RENUVA polyols are also used in
the manufacture of flexible elastomers, foams,
adhesives, coatings and sealants.
5 Castor oil is used as the raw material in
the BASF process. Castor oil (7 Sect. 2.2.7)
contains a high proportion of ricinoleic acid,
i.e. a C18:1 acid with an additional hydroxyl
group at the C12 position. BASF uses the
castor oil, i.e. the triglyceride, directly in the
hydroformylation and obtains a new triglyceride containing up to three hydroxyl groups
and three aldehyde functions. Hydrogenation
thus produces a polyol again. In a third step,
this polyol is etherified with ethylene oxide
or propylene oxide to form the final product,
the polyether polyols, which are marketed
under the name Lupranol Balance 35®. These
polyether polyols are used to produce rigid
foams for mattresses.
Both processes have the issue that a broad product spectrum is obtained by functionalization. In
addition, the resulting foams have relatively low
molecular weights.
Closely related to hydroformylation is hydroaminomethylation (HAM), a reaction with
synthesis gas and amines that leads to oleo compounds carrying an additional methylene amino
4.2 · Reactions at the C = C Double Bond of Unsaturated Oleochemicals