Process for the hydroformylation of olefinically unsaturated compounds

A process for the hydroformylation of olefinically unsaturated compounds whose hydroformylation products are insoluble or only sparingly soluble in water, comprising reacting the olefinically unsaturated compounds at 60.degree. to 180.degree. C. and 1 to 35 MPa with carbon monoxide and hydrogen in a homogeneous phase in a polar organic solvent and in the presence of a catalyst system comprising a rhodium carbonyl compound and a salt of a sulfonated or carboxylated organic monophosphine or polyphosphine, which salt is soluble both in the polar organic solvent and in water, distilling off the polar organic solvent from the reaction mixture and separating the catalyst system from the distillation residue by extraction with water.

STATE OF THE ART 
Two processes have become established in recent years for the 
hydroformylation of olefinically unsaturated compounds. One is carried out 
in a homogeneous phase, i.e. starting olefin, catalyst system (rhodium 
carbonyl and organic phosphine) and reaction products are present together 
as a solution and the reaction products are separated by distillation from 
the reaction mixture. The other process is distinguished by the presence 
of an aqueous catalyst phase which is separate from the reaction product 
and comprises rhodium carbonyl and a sulfonated or carboxylated organic 
phosphine. This variant of the reaction allows the isolation of the 
hydroformylation products without use of thermal process steps, it 
simplifies the recirculation of the catalyst and gives a particularly high 
proportion of unbranched aldehydes when using terminal olefins. 
The hydroformylation of higher, olefinically monounsaturated or 
polyunsaturated compounds is attracting increasing interest. It extends 
not only to the reaction of hydrocarbons, but also to compounds containing 
not only double bonds but also further reactive functional groups. An 
example of such classes of compounds having industrial importance is the 
unsaturated fatty acid esters which are frequently of natural origin or 
are prepared from natural raw materials and are available in large 
amounts. The reaction products of the hydroformylation, 
monoformylcarboxylic or polyformylcarboxylic esters, which can also 
contain double bonds which have not yet been reacted, are sought after 
intermediates which are processed further into widely used products such 
as polyamines, polyurethanes, alkyd resins, plasticizers and synthetic 
lubricants. 
The hydroformylation of higher, olefinically monounsaturated or 
polyunsaturated compounds by the homogeneous process using rhodium 
carbonyl/phosphine catalysts has been studied repeatedly. The economics of 
this process are only ensured when the homogeneously dissolved catalyst 
system can be separated without losses of the reaction , products and 
returned in active form to the hydroformylation reactor. Hitherto, it has 
only been possible to remove the catalyst from reaction mixtures 
containing formyl-fatty acid esters derived from the hydroformylation of 
monounsaturated fatty acid esters. However, the procedure requires 
complicated measures, in addition the catalyst is obtained in inactive 
form and the phosphine component of the catalyst system is completely lost 
J. Amer. Oil Chem. Soc., Vol. 50, p. 455 (1973)!. 
When using polyunsaturated compounds having isolated double bonds which are 
nevertheless close together, the hydroformylation can be carried out with 
avoidance of double bond isomerization, but the separation and 
recirculation of the catalyst homogeneously dissolved in the reaction 
product, for example by distillation, is not possible. 
Methyl esters of linoleic and linolenic acids can be hydroformylated in the 
presence of heterogenized rhodium carbonyl/phosphine complex catalysts 
based on polysiloxane Chemiker-Zeitung, Vol. 115 (1991) p. 39 ff!. When 
using methyl linoleate, the process give monoformylstearyl esters in 
yields of up to 79%, based on the doubly unsaturated ester used. On 
hydroformylation in the presence of the catalyst system mentioned, 
linolenic acid gives a maximum of 50% of diformyl compounds, while 
triformyl products are obtained at most in subordinate amounts (less than 
10%). The amount of rhodium carried out is on average about 0.5% of the 
noble metal originally used. It cannot be ruled out that a proportion of 
the catalyst metal is present in the homogeneous solution in equilibrium 
with the fixed metal, so that the hydroformylation takes place not only 
over the fixed bed catalyst, but also in solution. 
Difficulties associated with separating reaction product and catalyst 
system from one another do not occur in the hydroformylation of higher 
olefinically unsaturated compounds in the presence of an aqueous catalyst 
solution. However, because of the low solubility of the olefins in water, 
the conversion is often not satisfactory. This disadvantage can be avoided 
if, according to EP-B-157 316, the hydroformylation of olefins having more 
than 6 carbon atoms is carried out in the presence of an aqueous solution 
comprising rhodium complexes as catalyst and also a quaternary ammonium 
salt as solubilizer. A further development of this process is the subject 
matter of EP-B-163 234. According to this patent, olefins of 6 to 20 
carbon atoms are reacted with hydrogen and carbon monoxide in the presence 
of rhodium and the salt of a sulfonated arylphosphine whose cation is a 
quaternary ammonium ion. The quaternary ammonium salt of the phosphine 
here acts not only as a catalyst component, but at the same time as a 
solubilizer. Both processes relate exclusively to the reaction of 
monounsaturated compounds which contain no functional groups. 
OBJECTS OF THE INVENTION 
It is an object of the invention to develop a process which allows 
relatively high molecular weight, olefinically unsaturated compounds to be 
hydroformylated, with polyunsaturated starting materials being reacted not 
only partially, but completely to formyl compounds. 
It is another object of the invention to provide a hydroformylation process 
wherein the reaction product and catalyst system can be easily separated 
from each other and noble metal losses are largely avoided. 
These and other objects and advantages of the invention will become obvious 
from the following detailed description. 
THE INVENTION 
The novel process of the invention for the hydroformylation of olefinically 
unsaturated compounds whose hydroformylation products are insoluble or 
only sparingly soluble in water comprises reacting the olefinically 
unsaturated compounds at 60.degree. to 180.degree. C. and 1 to 35 MPa with 
carbon monoxide and hydrogen in a homogeneous phase in a polar organic 
solvent and in the presence of a catalyst system comprising a rhodium 
carbonyl compound and a salt of a sulfonated or carboxylated organic 
monophosphine or polyphosphine, which salt is soluble both in the polar 
organic solvent and in water, distilling off the polar organic solvent 
from the reaction mixture and separating the catalyst system from the 
distillation residue by extraction with water. 
The new process combines the characteristics of the hydroformylation in a 
homogeneous phase with the advantages of the hydroformylation in the 
presence of a heterogeneous, i.e. aqueous, catalyst phase to provide a 
new, forward-looking method of operation which is very well suited to 
reacting relatively high molecular weight olefinically monounsaturated or 
polyunsaturated compounds. It is used with particular success for 
hydroformylating esters of unsaturated, preferably polyunsaturated, fatty 
acids. 
Surprisingly, the process of the invention enables a plurality of double 
bonds present in the ester molecule, which can also be in non-terminal 
positions, to be simultaneously hydroformylated so that, for example, 
double unsaturated compounds give diformyl products and triple unsaturated 
compounds give triformyl products. Furthermore, the new process replaces 
the heterogeneous reaction system comprising olefinically unsaturated 
compound and aqueous catalyst solution which is characteristic for the 
reaction as described in EP-B-167 316 and EP-B-163 234 with a homogeneous 
solution of starting material and catalyst with the result that the 
reaction rate is increased and the conversion is improved. 
The relatively high molecular weight, olefinically unsaturated compounds 
suitable as starting materials for the process of the invention have to be 
soluble in the polar organic solvent used as the reaction medium and have 
to give hydroformylation products which are insoluble or only sparingly 
soluble in water. Accordingly, acyclic monoolefins having six or more 
carbon atoms particularly monoolefins of 10 to 30 carbon atoms such as 
tri- and tetrabutenes and tri- and tetraisobutenes can be reacted 
according to the new process. 
Polyunsaturated acyclic or cyclic olefins having at least six carbon atoms 
including, particularly monocyclic and bicyclic olefins, can also be 
successfully hydroformylated by the process of the invention. Examples of 
these classes of compounds are dicyclopentadiene, 1,5-cyclooctatriene, 
1,5,9-cyclododecatriene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene. 
The new procedure is particularly well suited, as mentioned above, for the 
hydroformylation of unsaturated fatty acid esters. These esters are 
derived particularly from double or triple unsaturated fatty acids of 8 to 
25, preferably from 10 to 20, carbon atoms and from saturated aliphatic 
monoalcohols of 1 to 10 carbon atoms, preferably methanol. These esters 
are obtained from natural oils which may, if desired, have previously been 
refined and distilled, by transesterification. Examples of natural oils as 
basis for the acid component of the starting ester are cottonseed oil, 
thistle oil, peanut oil, pumpkin kernel oil, linseed oil, maize oil, soy 
oil and sunflower oil. 
Catalysts used in the process claimed are systems which are soluble in 
polar organic solvents and in water and comprise a rhodium carbonyl 
compound as one component and, as a further component, a salt of a 
sulfonated or carboxylated organic phosphine, which salt is soluble both 
in water and in the polar organic solvent. 
Rhodium carbonyl and phosphine react to form a complex by part of the 
carbon monoxide molecules in the rhodium carbonyl compound being replaced 
by phosphine molecules as ligands. The solubility of the rhodium/phosphine 
complex is here determined by the solubility of the phosphine. Based on 
rhodium, the phosphine is usually present in excess, i.e. the catalyst 
system contains not only the rhodium/phosphine complex but also free 
phosphine. 
For the purposes of the present invention, the term "organic phosphines" 
refers to monophosphines or polyphosphines in which alkyl and/or aryl 
groups are bonded to the trivalent phosphorous atom or atoms, with at 
least one of these alkyl and/or aryl groups being singly or multiply 
sulfonated or carboxylated. Examples of aliphatic groups are 
straight-chain or branched saturated hydrocarbons of 2 to 8 carbon atoms 
and cyclic hydrocarbons of 5 to 8 carbon atoms. Typical aromatics are 
phenyl, benzyl and naphthyl. Both the aliphatics and aromatics can be 
substituted by further atom groups or atoms such as alkyl, hydroxyl or 
halogen. The description of organic phosphines also includes those 
compounds of trivalent phosphorus in which the phosphorus atom is a 
constituent of a heterocyclic ring. 
The phosphines present in the catalyst system do not have to be uniform 
chemical compounds, but can have different chemical compositions. Thus, 
they can differ, for example, in the type and bonding of the organic 
radicals attached to the phosphorus atom, in the degree of sulfonation or 
carboxylation or in the type of cations. The decisive factor for their 
suitability as the catalyst constituent is their solubility in water and 
in polar organic solvents. This criterion is met particularly by salts of 
sulfonated or carboxylated phosphines whose cation is lithium or an 
ammonium ion of the formula N(R.sup.1 R.sup.2 R.sup.3 R.sup.4).sup.+. 
R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are individually hydrogen or alkyl, 
preferably straight-chain or branched alkyl of 1 to 4 carbon atoms. 
The anions of the sulfonated or carboxylated monophosphines preferably 
correspond to the formula 
##STR1## 
wherein Ar.sup.1, Ar.sup.2, Ar.sup.3 are individually phenyl or naphthyl, 
X.sup.1, X2, X.sup.3 are individually sulfonate (--SO.sub.3.sup.-) and/or 
carboxylate (--COO.sup.-), Y.sup.1, Y.sup.2, Y.sup.3 are individually 
selected from the group consisting of straight-chain or branched alkyl of 
1 to 4 carbon atoms, alkoxy, halogen, --OH, --CN, --NO.sub.2 and (R.sup.5 
and R.sup.6)N in which R.sup.5 and R.sup.6 are individually alkyl of 1 to 
4 carbon atoms, m.sub.1, m.sub.2, m.sub.3 are individually integers from 0 
to 5, with the proviso that at least one m.sub.1, m.sub.2 or m.sub.3 is 
greater than 0; n.sub.1, n.sub.2, n.sub.3 are individually integers from 0 
to 5. 
Particularly suitable salts are derived from the anion of formula I in 
which Ar.sup.1, Ar.sup.2, Ar.sup.3 are each phenyl and X.sup.1, X.sup.2, 
X.sup.3 are each sulfonate located in the meta position relative to the 
phosphorus, i.e. salts of tris(m-sulfonatophenyl)phosphine (abbreviated as 
TPPTS). Other salts which have been found to be. suitable as a catalyst 
component are those of diphenyl(m-sulfonato-phenyl) phosphine (abbreviated 
as TPPMS), particularly the lithium salt (Li-TPPMS). 
A further group of monophosphine anions which have been found to be 
suitable as catalyst components are those of the formula 
EQU A.sub.2 P--(CH.sub.2).sub.n --CH(R)--SO.sub.3.sup.- II 
where the As are individually alkyl and/or aryl, n is 0, 1 or 2 and R is 
hydrogen or alkyl. The compounds are obtained by sulfalkylation of 
dialkylphosphines or diarylphosphines with 1,2-, 1,3- or 1,4-sultones 
##STR2## 
where n = 1, 2 or 3 and R = H, alkyl, e.g. in accordance with 
##STR3## 
The alkali metal salt can be converted into an ammonium salt by customary 
methods. 
The anion can be formed not only from monophosphines but also from 
polyphosphines, particularly diphosphines containing at least one 
sulfonated or carboxylated organic. Diphosphine anions are preferably 
derived from diaryl compounds of the formula 
##STR4## 
which are substituted by at least one sulfonate (--SO.sub.3.sup.-) or 
carboxylate (--COO.sup.-). In the formula, the R.sup.7 s are individually 
selected from the group consisting of alkyl, cycloalkyl, phenyl, tolyl and 
naphthyl, the R.sup.8 s are individually selected from the group 
consisting of hydrogen, alkyl and alkoxy of 1 to 14 carbon atoms, 
cycloalkyl, aryl or aryloxy of 6 to 14 carbon atoms and a fused-on benzene 
ring, the m.sub.4 s are individually integers from 0 to 5 and n.sub.4 s 
are individually integers from 0 to 4. 
Preference is given to the sulfonated compounds which can be obtained by 
conventional methods. Representatives of this class of compounds which 
have been found to be useful are the products obtained by sulfonation of 
2,2 'bis(diphenyl-phosphinomethyl) -1,1'-biphenyl or 
2,2'-bis(diphenyl-phosphinomethyl)-1,1'-binaphthyl. An example of the 
anion of a heterocyclic phosphorus compound which may be mentioned is 
3,4-dimethyl-2,5,6-tris(p-sulfonatophenyl)-1-phosphanorbornadiene. 
The reaction of the olefinically unsaturated starting compounds with 
hydrogen and carbon monoxide is carried out at temperatures of 60.degree. 
to 180.degree. C., particularly 100.degree. to 140.degree. C., and at 
pressures of 1 to 35 MPa. For the hydroformylation of olefins, pressures 
of from 2 to 35 MPa have been found to be particularly useful and esters 
of unsaturated fatty acids are preferably reacted at pressures of from 15 
to 25 MPa. 
The reaction is carried out in a reaction medium comprising a polar organic 
solvent which dissolves not only the olefinically unsaturated starting 
compound but also the reaction product and catalyst system. Suitable 
solvents are low molecular weight aliphatic alcohols of one to four carbon 
atoms. Instead of pure solvents, it is also possible to use mixtures of 
two or more of these alcohols such as methanol/ethanol, or 
methanol/i-propanol mixtures. Reaction media which have been found to be 
particularly useful are methanol and ethanol which can contain up to 5% by 
weight of water, but are preferably used in anhydrous form. 
The catalyst can be preformed before addition to the reaction system. 
However, it can be equally successfully prepared in the reaction mixture, 
i.e. olefinically unsaturated compound and solvent, under reaction 
conditions from the components rhodium or rhodium compound and the 
solution of the sulfonated or carboxylated phosphine. Apart from metallic 
rhodium in finely divided form, it is also possible to use inorganic 
rhodium salts such as rhodium chloride, rhodium sulfate, rhodium salts of 
organic acids such as rhodium acetate, rhodium 2-ethylhexanoate or rhodium 
oxides as rhodium source. 
The rhodium concentration in the reaction solution is from 100 to 600 ppm 
by weight, preferably from 300 to 400 ppm by weight, based on the 
solution. The phosphine is used in such an amount that at least 20 moles, 
preferably from 40 to 80 moles, of P(III) are present per mole of rhodium. 
The pH of the reaction solution should not go below a value of 3. A pH of 4 
to 11 is generally set. When using methanol as solvent, acetylation of the 
aldehydes formed by hydroformylation can occur. If it is desired to 
protect the carbonyl from secondary reactions, it is advisable to work at 
a pH of 4.5 to 6.5, preferably 5.5 to 6.0. 
The ratio of carbon monoxide to hydrogen in the synthesis gas can be varied 
within wide limits. Generally, the synthesis gas used is one in which the 
volume ratio of carbon monoxide to hydrogen is 1:1 or deviates only little 
from this value. The reaction can be carried out either batchwise or 
continuously. 
For working up the reaction product, the polar organic solvent is first 
distilled off. The distillation residue is then washed with water, 
preferably at ambient temperature, to remove the catalyst system from the 
aldehydes. This treatment can be repeated a plurality of times, if 
appropriate. To recover the rhodium completely, it has been found to be 
advantageous to add a phosphine capable of complex formation with rhodium, 
advantageously a phosphine which is simultaneously a catalyst component, 
to the wash water.

In the following examples, there are described several preferred 
embodiments to illustrate the invention. However, it is to be understood 
that the invention is not intended to be limited to the specific 
embodiments. 
EXAMPLE 1 
A Schlenk tube which has been flushed with argon was charged with 15 ml of 
methanol, 60 mg (0.05 mmol) of a 8.5% strength by weight rhodium solution 
(as aqueous Rh.sub.2 (SO.sub.4).sub.3 solution) and 700 mg (2 mmol) of 
diphenyl(lithium 4-sulfonatobutyl)phosphine and the P/Rh molar ratio was 
40. The pH of the solution was adjusted to 5 and the solution was 
introduced by means of a syringe into a laboratory autoclave which had 
been flushed and filled with argon. 15 g of a 90% strength by weight of 
methyl linolenate (remainder: methyl linoleate) were placed in the 
pressure-resistant dropping funnel of the autoclave. The autoclave was 
flushed with water gas, and a reaction pressure of 20 MPa and a reaction 
temperature of 120.degree. C. were then set. After a reaction time of one 
hour, the methyl linolenate was added dropwise and the pressure decrease 
was monitored via a pressure sensor and a recorder. Gas absorption was 
complete after 10 hours. The autoclave was cooled, vented and its contents 
were freed of methanol by distillation under exclusion of air (argon). The 
residue was washed twice with 15-20 ml each time with oxygen-free water to 
extract the catalyst system and it was then analyzed. The conversion of 
linolenic and linoleic esters was quantitative, and the yields were: 
5% of monoformyl product based on the total starting materials, 
22% of diformyl product based on the total starting materials and 
82% of triformyl product based on the proportion of methyl linolenate used 
in the starting material. 
EXAMPLES 2 to 6 
Examples 2 to 6 were carried out in a similar manner to Example 1 with 
variation of the pressure, the pH of the catalyst solution and the P/Rh 
ratio. The results obtained are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Temp. 
Pressure 
Time.sup.1) 
MF.sup.2) 
DF.sup.3) 
TF.sup.4) 
Conversion 
Ex. 
P/Rh 
pH 
.degree.C.! 
MPa! 
h! mol %! %! 
__________________________________________________________________________ 
2 40 8.4 
120 20 3 4 24 80 100 
3 20 5.0 
120 20 3 14 44 47 100 
4 10 5.0 
120 20 3 16 44 45 100 
5 10 5.0 
120 7 3 20 50 34 100 
6 20 5.0 
120 7 3 15 59 40 100 
__________________________________________________________________________ 
.sup.1) Time after which from 90 to 95% of the gas had been absorbed 
.sup.2) Monoformyl product, based on total starting material 
.sup.3) Diformyl product, based on total starting material 
.sup.4) Triformyl product, based on methyl linolenate used 
EXAMPLE 7 
A 100 ml V4A stainless steel autoclave which had been flushed with argon 
and was fitted with a magnetic stirrer, a pressure-resistant metering 
vessel, a thermocouple support and a pressure sensor (expansion measuring 
strips) was charged with 24 mg of rhodium (0.05 mmol) as an aqueous 
Rh.sub.2 (SO.sub.4).sub.3 solution and 2.2 g (3 mmol) of 
tris(tetramethylammonium m-sulfonatophenyl)phosphine dissolved in 30 ml of 
methanol (P/Rh molar ratio:60). The autoclave was closed, flushed with 
water gas and a reaction temperature of 120.degree. C. and a reaction 
pressure of 2 MPa were set. 10 g (50 mmol) of methyl 10-undecenoate were 
then added from the metering vessel and after 1 hour, the reaction was 
stopped. 97% of a mixture of 71% of methyl 11-formylundecanoate and 29% of 
methyl 10-formylundecanoate was formed, as well as 3% of the hydrogenation 
product, methyl undecanoate. After distilling off the methanol, the 
catalyst system was taken up in water and separated from the reaction 
product by phase separation. 
EXAMPLE 8 
Example 7 was repeated at a reaction pressure of 1 MPa under otherwise 
identical conditions and conversion was complete after only 30 minutes. 
Only 1% of methyl undecanoate was obtained in addition to 99% of a mixture 
of 70% by weight of methyl 11-formylundecanoate and 30% by weight of 
methyl 10-formylundecanoate. The catalyst system was taken up in water 
after distilling off the methanol and separated from the reaction product. 
EXAMPLE 9 
Under argon as a protective gas, 15 ml of methanol, 0.05 mmol of Rh in the 
form of 60 mg of a 8.5% strength rhodium solution (as aqueous Rh.sub.2 
(SO.sub.4).sub.3 solution) and 348 mg (1 mmol) of Li-TPPMS (P/Rh molar 
ratio: 20) were placed in a Schlenk tube. The pH of the solution was 
adjusted to 6 and the solution was placed in an autoclave under argon. 
After closing and flushing the autoclave with water gas, a reaction 
pressure of 10 MPa and a reaction temperature of 120.degree. C. were set. 
12 g (60 mmol) of n-tetradec-1l-ene were added from a metering vessel and 
after 1 hour, the olefin had been completely reacted. 98% of a 
hydroformylation product containing 72% by weight of n-pentadecanal and 
28% by weight of 2-methyl-tetradecanal was formed, as well as 2% of the 
hydrogenation product, n-tetradecane. The aldehydes were mainly (about 
70%) obtained in the form of dimethyl acetals. After distilling off most 
of the methanol solvent, the reaction product was admixed with about 10 ml 
of water to separate off the catalyst complex. The organic phase was 
extracted once more with about 5 ml of water. After combining the aqueous 
extracts, the water was distilled off under reduced pressure and the 
catalyst system was redissolved in methanol. 
EXAMPLES 10 to 15 
The catalyst system recovered as described in Example 9 was repeatedly used 
for the hydroformylation of n-tetradec-1-ene and the conditions were the 
same as in Example 9. The results of the experiments are shown in Table 2. 
TABLE 2 
______________________________________ 
Conver- n-Penta 
2-Methyltetra- 
sion Yield decanal 
decanal Tetra- 
Example 
(%) (%) (%) (%) decane (%) 
______________________________________ 
10 100 98 72 28 2 
11 100 96 70 30 4 
12 100 98 71 29 2 
13 100 99 70 30 1 
14 100 98 71 29 2 
15 100 97 70 30 3 
______________________________________ 
EXAMPLE 16 
Under argon as a protective gas, 25 ml of methanol, 0.05 mmol of Rh in the 
form of 60 mg of an 8.5% strength rhodium solution (as aqueous Rh.sub.2 
(SO.sub.4).sub.3 solution) and 348 mg (1 mmol) of Li-TPPMS (P/Rh molar 
ratio:20) were placed in a Schlenk tube. The pH of the solution was 
adjusted to 11 and the solution was placed in an autoclave under argon. 
After closing and flushing the autoclave with water gas, a reaction 
pressure of 10 MPa and a reaction temperature of 120.degree. C. were set. 
12 g (60 mmol) of n-tetradec-1-ene were added from a metering vessel and 
after 1 hour, the olefin had been completely reacted. 98% of a 
hydroformylation product containing 71% by weight of n-pentadecanal and 
29% by weight of 2- methyl-tetradecanal was formed, as well as 2% of the 
hydrogenation product, n-tetradecane. Only 3% of the aldehydes formed were 
obtained as dimethyl acetals (as a result of the high pH of 11). 
EXAMPLE 17 
Under argon as a protective gas, 15 ml of methanol, 0.05 mmol of Rh in the 
form of 60 mg of an 8.5% strength rhodium solution (as Rh.sub.2 
(SO.sub.4).sub.3 solution) and 348 mg (1 mmol) of Li-TPPMS (P/Rh molar 
ratio:20) were placed in a Schlenk tube. The pH of the solution was 
adjusted to 6 and the solution was placed in an autoclave under argon. 
After closing and flushing the autoclave with water gas, a reaction 
pressure of 20 MPa and a reaction temperature of 120.degree. C. were set. 
16 g (50 mmol) of technical-grade methyl linolenate (55% of methyl 
linolenate, remainder about 15% of methyl linoleate, about 20% of methyl 
oleate) were added from a metering vessel and after 3 hours, the olefin 
was completely reacted. The reaction mixture contained 23% by weight of 
monoformyl product, 22% by weight of diformyl product and 47% by weight of 
triformyl product. Based on the proportion of methyl linolenate of 55% in 
the technical product, this represented a selectivity of 85% based on the 
formation of the triply hydroformylated product. 
Various modifications of the process of the invention may be made without 
departing from the spirit or scope thereof and it is to be understood that 
the invention is intended to be limited only as defined in the appended 
claims.