Process for preparing aldehydes by hydroformylation

The invention concerns a process for preparing aldehydes by reacting with hydrogen and carbon monoxide at a temperature of between 20 and 170.degree. C. and a pressure of between 1 and 300 bar an olefinically unsaturated C.sub.3 -C.sub.5 compound in the presence of an aqueous phase containing rhodium and sulphonated triarylphosphines as catalyst and between 1 and 35 wt % of a compound of formula (1), R(OCH.sub.2 CH.sub.2).sub.n OR.sup.1, R standing for hydrogen, a straight-chain or branched C.sub.1 -C.sub.4 alkyl group or a C.sub.1 -C.sub.4 hydroxyalkyl group, R.sup.1 standing for hydrogen or a methyl group, and n standing for an integer from 3 to 50.

The present invention relates to a process for preparing aldehydes by
 reacting olefinic compounds having from 3 to 5 carbon atoms with hydrogen
 and carbon monoxide at superatmospheric pressure in the presence of an
 aqueous phase comprising rhodium and sulfonated triarylphosphines as
 catalyst.
 It is known that aldehydes and alcohols can be prepared by reacting olefins
 with carbon monoxide and hydrogen. The reaction is catalyzed by
 hydrido-metal carbonyls, preferably those of metals of group VIII of the
 Periodic Table. Besides cobalt, which is widely used industrially as
 catalyst metal, rhodium has recently achieved increasing importance. In
 contrast to cobalt, rhodium allows the reaction to be carried out at low
 pressure; in addition, straight-chain n-aldehydes are preferentially
 formed and iso-aldehydes are formed to only a subordinate extent. Finally,
 significantly less hydrogenation of the olefins to saturated hydrocarbons
 occurs when using rhodium catalysts than when using cobalt catalysts.
 In the processes which have been introduced in industry, the rhodium
 catalyst is used in the form of modified hydrido-rhodium carbonyls which
 contain additional ligands which may, if appropriate, be used in excess.
 Tertiary phosphines or phosphites have been found to be particularly
 useful as ligands. Their use makes it possible to reduce the reaction
 pressure to below 30 MPa.
 However, the separation of the reaction products and the recovery of the
 catalysts homogeneously dissolved in the reaction product create problems
 in this process. In general, the reaction product is distilled from the
 reaction mixture. In practice however, owing to the thermal sensitivity of
 the aldehydes and alcohols formed, this method can only be employed in the
 hydroformylation of lower olefins, i.e. olefins having up to about 5
 carbon atoms in the molecule.
 The hydroformylation of long-chain olefins or olefinic compounds containing
 functional groups forms products having a high boiling point and these
 cannot be separated from the homogeneously dissolved rhodium complex
 catalyst by distillation. The thermal stressing of the material being
 distilled leads to considerable losses of desired products due to thick
 oil formation and of catalyst due to decomposition of the rhodium
 complexes.
 The separation of the catalyst by thermal means is avoided by use of
 water-soluble catalyst systems. Such catalysts are described, for example,
 in DE-C 26 27 354. The solubility of the rhodium complexes is here
 achieved by use of sulfonated triarylphosphines as constituent of the
 complex. In this process variant, the catalyst is separated from the
 reaction product after the hydroformylation reaction is complete simply by
 separating the aqueous and organic phases, i.e. without distillation and
 thus without additional thermal process steps. A further feature of this
 procedure is that n-aldehydes are formed with high selectivity from
 terminal olefins and iso-aldehydes are formed to only a very subordinate
 extent. Apart from sulfonated triarylphosphines, carboxylated
 triarylphosphines are also used as constituents of water-soluble rhodium
 complexes.
 The use of water-soluble catalysts has been found to be useful in the
 hydroformylation of lower olefins, in particular propene and butene.
 However, if higher olefins such as pentene or hexene are used, the
 reaction rate is noticeably reduced. An industrial-scale reaction is
 frequently no longer as economical as desired when using olefins having
 four or more carbon atoms.
 In order to increase the conversion and/or the selectivity of the reaction
 to n-aldehydes in the hydroformylation of higher olefins by means of
 water-soluble catalysts, the addition of an amphiphilic reagent (DE 31 35
 127 A1) or a solubilizer (DE 34 12 335 A1) has been recommended.
 According to both DE 31 35 127 A1 and DE 34 12 335, very high conversions
 are obtained using quaternary ammonium salts which have a long-chain alkyl
 radical, while nonionic substances based on polyethylene glycol lead to
 comparatively low conversions.
 As can be seen from Table 7 in DE 31 35 127, the hydroformylation of
 1-dodecene by means of rhodium and monosulfonated triphenylphosphine
 (3-Ph.sub.2 PC.sub.6 H.sub.4 SO.sub.3 Na) without addition of an
 amphiphilic reagent leads to a conversion of 56% (Example 77), while the
 addition of C.sub.12 H.sub.25 (OCH.sub.2 CH.sub.2).sub.23 OH (="Brij 35")
 leads to a reduction in the conversion to 37% (Example 78).
 According to DE 34 12 335 (Table 4), the hydroformylation of hexene by
 means of rhodium and trisodium tri(m-sulfophenyl)phosphine without
 addition of a solubilizer leads to a conversion of 36% (Example 10), while
 addition of 2.5% of triethylene glycol (Example 14) or 5% of polyglycol
 200 (Example 11) gives a conversion of 43.5% or 43% respectively. The
 addition of the solubilizer results in no significant increase in the
 conversion, and increasing the amount of solubilizer from 2.5% to 5% also
 does not increase the conversion. On the other hand, a very high
 conversion, namely 86%, is achieved with an addition of 2.5% of
 trimethylhexadecylammonium bromide.
 However, the use of quaternary ammonium salts as amphiphilic reagent or
 solubilizer is not without problems because of the poor biodegradability
 of these compounds. Thus, the presence of quaternary ammonium salts in
 wastewater leads to difficulties in wastewater treatment.
 Amphiphilic reagents and solubilizers serve to aid mass transfer between
 the individual phases and thus the miscibility of aqueous catalyst phase
 and organic phase. An increase in the miscibility of aqueous catalyst
 phase and organic phase means an increased solubility of the organic phase
 in the aqueous phase and of the aqueous phase in the organic phase. In
 this way, increasing amounts of amphiphilic reagent and solubilizer and
 also rhodium and water-soluble phosphine can get into the organic phase
 and be carried off with the organic phase after phase separation.
 Furthermore, it is to be expected that with increasing miscibility of
 aqueous catalyst phase and organic phase the demixing required for phase
 separation will no longer take place to a sufficient extent, if at all, as
 a result of the formation of emulsions or solutions. A corresponding
 increase in the miscibility is to be expected particularly when the amount
 of amphiphilic reagents and solubilizers added is increased.
 Increased discharge of rhodium, water-soluble phosphine and amphiphilic
 reagent or solubilizer via the organic phase is, like reduced
 demiscibility of the phases, undesirable, since the rhodium, water-soluble
 phosphine and amphiphilic reagent or solubilizer should remain in the
 aqueous catalyst phase and good demiscibility is an essential prerequisite
 for the separation of organic and aqueous phases which is necessary at the
 end of the hydroformylation.
 In view of the above considerations, there is a need for a process which
 avoids the abovementioned disadvantages and, in addition, can be
 implemented industrially in a simple manner.
 This object is achieved by a process for preparing aldehydes. It comprises
 reacting an olefinically unsaturated compound having from 3 to 5 carbon
 atoms with hydrogen and carbon monoxide at from 20 to 170.degree. C. and
 from 1 to 300 bar in the presence of an aqueous phase comprising rhodium
 and sulfonated triarylphosphines as catalyst and from 1 to 35% by weight
 of a compound of the formula (1) R(OCH.sub.2 CH.sub.2).sub.n OR.sup.1,
 where, in the formula (1), R is hydrogen, a straight-chain or branched
 alkyl radical having from 1 to 4 carbon atoms or a hydroxyalkyl radical
 having from 1 to 4 carbon atoms, R.sup.1 is hydrogen or a methyl radical,
 in particular hydrogen, and n is an integer from 3 to 50.
 In view of the abovementioned findings of DE 34 12 335 (Table 4, Examples
 10, 14 and 11) and DE 31 35 127 (Table 7, Examples 77 and 78) for the
 hyroformylation of hexene and dodecene, it was not to be expected that
 addition of compounds of the formula (1) R(OCH.sub.2 CH.sub.2).sub.n
 OR.sup.1 in the abovementioned amounts in the reaction of olefinic
 compounds having only 3 to 5 carbon atoms would lead to a significant
 increase in the conversion and at the same time to a high selectivity in
 respect of the formation of n-aldehydes.
 If propene is hydroformylated in the presence of an aqueous phase
 comprising rhodium and trisulfonated triphenylphosphine, a very high
 reaction rate is obtained in the absence of an amphiphilic reagent or
 solubilizer.
 In view of this, it is surprising that a comparatively small addition of
 compounds of the formula (1) leads to a noticeable increase in the already
 very high propylene conversion rate. Furthermore, it was not to be
 expected that despite this conversion increase the ratio of formation of
 n-butanal to iso-butanal would be influenced only very slightly. The
 formation of n-butanal is reduced by only a very small amount compared to
 the procedure without addition of compounds of the formua (1).
 In view of the great influence which even a comparatively small addition of
 compounds of the formula (1) has on the propylene conversion, it is also
 unexpected that rhodium, the sulfonated triarylphosphine and the compound
 of the formula (1) remain virtually completely in the aqueous phase and do
 not get into the organic phase and are not lost from the aqueous phase via
 the organic phase.
 It is also generally surprising that in the hydroformylation of olefinic
 compounds having from 3 to 5 carbon atoms, even the addition of
 comparatively large amounts of compounds of the formula (1) R(OCH.sub.2
 CH.sub.2).sub.n OR.sup.1 does not cause a significant increase in the
 amount of rhodium and sulfonated triarylphosphine in the organic phase and
 thus to increased discharge of the catalyst via the organic phase.
 In addition, it was not to be expected that, despite the comparatively
 large amounts of compounds of the formula (1), the demiscibility of
 organic phase and aqueous catalyst phase is high enough to ensure the
 separation of organic phase and aqueous catalyst phase. Surprisingly,
 difficult-to-separate emulsions or homogeneous phases or solutions which
 cannot be separated are not formed.
 The aqueous phase comprising the catalyst and the compound of the formula
 (1) R(OCH.sub.2 CH.sub.2).sub.n OR.sup.1 can be prepared in a
 comparatively simple way by dissolving a water-soluble rhodium salt, the
 sulfonated triarylphosphines and the compound of the formula (1) in water.
 Suitable rhodium salts are, without making any claim to completeness:
 rhodium(III) sulfate, rhodium(III) nitrate, rhodium(III) carboxylates such
 as rhodium acetate, rhodium propionate, rhodium butyrate and rhodium
 2-ethylhexanoate.
 The aqueous phase can be used directly in the hydroformylation or subjected
 beforehand to a preformation of the catalyst under reaction conditions and
 used subsequently in preformed form.
 The olefinic compound used can be an aliphatic olefin or cycloaliphatic
 olefin having from 3 to 5 carbon atoms, in particular an aliphatic olefin
 having from 3 to 5 carbon atoms, preferably an aliphatic .alpha.-olefin
 having from 3 to 5 carbon atoms.
 The olefinic compound can contain one or more carbon-carbon double bonds.
 The carbon-carbon double bond can be in a terminal or internal position.
 Preference is given to olefinic compounds having a terminal carbon-carbon
 double bond.
 Examples of .alpha.-olefinic compounds (with a terminal carbon-carbon
 double bond) are alkenes, alkyl alkenoates, alkenyl alkanoates, alkenyl
 alkyl ethers and alkenols.
 Without claiming completeness, olefinic compounds which may be mentioned
 are propene, cyclopropene, butene, pentene, butadiene, pentadiene,
 cyclopentene, cyclopentadiene, allyl acetate, vinyl formate, vinyl
 acetate, vinyl propionate, allyl methyl ether, vinyl methyl ether, vinyl
 ethyl ether, and allyl alcohol, in particular propene, 1-butene,
 industrially available mixtures containing essentially 1-butene and
 2-butene, and 1-pentene.
 For the purposes of the present invention, sulfonated triarylphosphines are
 phosphines which contain one or two phosphorus atoms, which have three
 aryl radicals per phosphorus atom, where the aryl radicals are identical
 or different and are each a phenyl, naphthyl, biphenyl, phenylnaphthyl or
 binaphthyl radical, in particular a phenyl, biphenyl or binaphthyl
 radical, and the aryl radicals are connected to the phosphorus atom either
 directly or via a --(CH.sub.2).sub.x -- group, where x is an integer from
 1 to 4, in particular from 1 to 2, preferably 1, and which contain at
 least three --(SO.sub.3)M groups, where M are identical or different and
 are each H, an alkali metal ion, an ammonium ion, a quaternary ammonium
 ion, a 1/2 alkaline earth metal ion or 1/2 zinc ion, in particular an
 alkali metal ion, an ammonium ion or a quaternary ammonium ion, preferably
 an alkali metal ion. The --SO.sub.3 M groups are usually located as
 substituents on the aryl radicals and give the triarylphosphines the
 required water solubility.
 As sulfonated triarylphosphines containing one phosphorus atom, preference
 is given to using compounds of the formula (2)
 ##STR1##
 where Ar.sup.1, Ar.sup.2 and Ar.sup.3 are identical or different and are
 each a phenyl or naphthyl radical, in particular a phenyl radical, and M
 are identical or different, in particular identical, and are each an
 alkali metal ion, an ammonium ion, a quaternary ammonium ion or a 1/2
 alkaline earth metal ion or 1/2 zinc ion, in particular an alkali metal
 ion or ammonium ion, preferably an alkali metal ion, particularly
 preferably a sodium ion.
 Trisodium tri(m-sulfophenyl)phosphine is particularly suitable as
 sulfonated triarylphosphine. This trisodium salt of
 tri(meta-sulfophenyl)phosphine contains, owing to its preparation by
 sulfonation of triphenylphosphine, amounts of monosulfonated and
 disulfonated compounds.
 Trisodium tri(m-sulfophenyl)phosphine corresponds to the following formula:
 ##STR2##
 The sulfonated triarylphosphines containing two phosphorus atoms can, for
 example, contain a radical --(CH.sub.2).sub.x --Ar--Ar--(CH.sub.2).sub.x
 --, where x is an integer from 1 to 4, in particular from 1 to 2,
 preferably 1, Ar--Ar is biphenyl or binaphthyl, the --(CH.sub.2).sub.x --
 group is, via one bond, in each case located in the ortho position to the
 aryl-aryl bond Ar--Ar connecting the two aryl radicals and is connected
 via the other bond to a phosphorus atom which in each case bears two
 further, identical or different aryl radicals, in particular phenyl
 radicals. These triarylphosphines containing two phosphorus atoms have at
 least three --SO.sub.3 M groups, in particular from 4 to 8 --SO.sub.3 M
 groups, where M is as defined above. The --SO.sub.3 M groups are usually
 located on the aryl radicals of the radical --(CH.sub.2).sub.x
 --Ar--Ar--(CH.sub.2).sub.x -- and on the two further aryl radicals which
 are connected to the phosphorus.
 Examples of such sulfonated triarylphosphines containing two phosphorus
 atoms are, without making any claim as to completeness, represented by the
 formulae (3) and (4) below:
 ##STR3##
 In (3), m.sub.1 and m.sub.2 are each, independently of one another, 0 or 1,
 with the compound of the formula (3) containing from three to six
 --SO.sub.3 M groups.
 ##STR4##
 In (4), m.sub.3, m.sub.4, m.sub.5 and m.sub.6 are each, independently of
 one another, 0 or 1, with the compound of the formula (4) containing from
 four to eight, in particular from five to six, --SO.sub.3 M groups.
 Since the compounds (3) and (4) are prepared by sulfonation of the
 corresponding phosphines of the formulae (3a) and (4a) which contain no
 --SO.sub.3 M groups,
 ##STR5##
 they are usually obtained in the form of mixtures of compounds containing
 different numbers of --SO.sub.3 M groups. Thus, a compound of the formula
 (3) or (4) which contains, for example, three --SO.sub.3 M groups also
 contains compounds having only two --SO.sub.3 M groups as well as
 compounds having four or five --SO.sub.3 M groups. A compound of the
 formula (3) or (4) having, for example, five --SO.sub.3 M groups usually
 also contains compounds having only three or four --SO.sub.3 M groups as
 well as compounds having six or seven --SO.sub.3 M groups.
 Compounds of the formula (3) have a maximum of six --SO.sub.3 M groups,
 while compounds of the formula (4) have a maximum of eight --SO.sub.3 M
 groups.
 For this reason, mixtures of compounds of the formula (3) or (4) having a
 different number of --SO.sub.3 M groups are generally used.
 The above-described sulfonated triarylphosphines have, owing to their
 sulfonate radicals, a solubility in water which is sufficient for carrying
 out the process.
 The aqueous phase comprising rhodium and the compounds of the formula (2)
 as catalyst and the compound of the formula (1) is usually used in an
 amount corresponding to from 2.times.10.sup.-6 to 5.times.10.sup.-2 mol,
 in particular from 5.times.10.sup.-5 to 5.times.10.sup.-2 mol, preferably
 from 1.times.10.sup.-4 to 1.times.10.sup.-3 mol, of rhodium per mol of
 olefinic compound.
 The amount of rhodium also depends on the type of olefinic compound to be
 hydroformylated. Although lower catalyst concentrations are possible, in
 some cases they can prove to be not particulary appropriate, since the
 reaction rate can be too low and therefore not economical enough. The
 catalyst concentration can be up to 1.times.10.sup.-1 mol of rhodium per
 mol of olefinic compound, but comparatively high rhodium concentrations
 give no particular advantages.
 The aqueous phase comprising rhodium and sulfonated triarylphosphines as
 catalyst and the compound of the formula (1) R(OCH.sub.2 CH.sub.2).sub.n
 OR.sup.1 is usually used in a volume ratio to the olefinic compound of
 from 10:1 to 1:10, in particular from 5:1 to 1:5, preferably from 2:1 to
 1:2.
 Rhodium and sulfonated triarylphosphines are used in a molar ratio of from
 1:5 to 1:2000.
 If use is made of a sulfonated triarylphosphine containing one phosphorus
 atom, for example a compound of the formula (2), rhodium and sulfonated
 triarylphosphine are usually used in a molar ratio of from 1:10 to 1:1000,
 in particular from 1:50 to 1:200, preferably from 1:80 to 1:120.
 If use is made of a sulfonated triarylphosphine containing two phosphorus
 atoms (for example a compound of the formula (3) or (4)), rhodium and
 sulfonated triarylphosphine are usually used in a molar ratio of from 1:5
 to 1:100, in particular from 1:5 to 1:50, preferably from 1:8 to 1:15.
 The aqueous phase contains from 20 to 2000 ppm of rhodium. If a sulfonated
 triarylphosphine containing one phosphorus atom, for example a compound of
 the formula (2), is employed, use is in most cases made of an aqueous
 phase containing from 100 to 1000 ppm, in particular from 200 to 500 ppm,
 preferably from 300 to 400 ppm, of rhodium.
 If a sulfonated triarylphosphine containing two phosphorus atoms, for
 example compounds of the formula (3) and/or (4), is employed, use is in
 most cases made of an aqueous phase which contains from 20 to 500 ppm, in
 particular from 30 to 150 ppm, preferably from 40 to 100 ppm, of rhodium.
 The type of oleifinic compound to be reacted can to a certain extent also
 influence the amount of the compound of the formula (1) R(OCH.sub.2
 CH.sub.2).sub.n OR.sup.1 to be used.
 If the olefinic compound used is propene, it has frequently been found to
 be appropriate to carry out the reaction in the presence of an aqueous
 phase containing from 1 to 15% by weight, in particular from 3 to 10% by
 weight, of the compound of the formula (1).
 If the olefinic compound used is butene, it has frequently been found to be
 appropriate to carry out the reaction in the presence of an aqueous phase
 containing from 5 to 25% by weight, in particular from 8 to 20% by weight,
 of the compound of the formula (1).
 If the olefinic compound used is pentene, it has frequently been found to
 be appropriate to carry out the reaction in the presence of an aqueous
 phase containing from 5 to 35% by weight, in particular from 8 to 30% by
 weight, of the compound of the formula (1).
 At this point, it may be mentioned for the sake of completeness that the
 compounds of the formula (1) R(OCH.sub.2 CH.sub.2).sub.n OR.sup.1, where R
 is hydrogen, a straight-chain or branched alkyl radical having from 1 to 4
 carbon atoms or a hydroxyalkyl radical having from 1 to 4 carbon atoms, in
 particular hydrogen, an alkyl radical having from 1 to 2 carbon atoms or a
 hydroxyalkyl radical having from 1 to 3 carbon atoms, preferably hydrogen,
 methyl, hydroxymethyl or hydroxypropyl, and R.sup.1 is hydrogen or a
 methyl radical, in particular hydrogen, are substances which dissolve in
 water to a sufficient extent.
 Attention may be drawn at this point to the following compounds of the
 formula (1) in which R.sup.1 is hydrogen and which are of particular
 interest.
 Without making any claim as to completeness, compounds of the formula
 R(OCH.sub.2 CH.sub.2).sub.n OH which may be mentioned are polyethylene
 glycol of the formula H(OCH.sub.2 CH.sub.2).sub.n OH having a mean
 molecular weight of about 200 (PEG 200), 400 (PEG 400), 600 (PEG 600) or
 1000 (PEG 1000), compounds of the formula CH.sub.3 (OCH.sub.2
 CH.sub.2).sub.n OH having a mean molecular weight of about 350 (M 350),
 500 (M 500) or 750 (M 750) or compounds of the formula CH.sub.3
 CHOHCH.sub.2 (OCH.sub.2 CH.sub.2).sub.n OH having a mean molecular weight
 of about 300 (300 PR), 450 (450 PR), 600 (600 PR) or 1000 (1000 PR), in
 particular polyethylene glycol having a mean molecular weight of about 400
 (PEG 400) and 600 (PEG 600), a compound of the formula CH.sub.3 (OCH.sub.2
 CH.sub.2).sub.n OH having a mean molecular weight of 500 (M 500) or a
 compound of the formula CH.sub.3 CHOHCH.sub.2 (OCH.sub.2 CH.sub.2).sub.n
 OH having a mean molecular weight of 450 (450 PR) and 600 (600 PR).
 For the purposes of the present invention, PEG 200 is a mixture of
 polyethylene glycols of the formula H(OCH.sub.2 CH.sub.2).sub.n OH, where
 n is an integer from 3 to 6, PEG 400 is a mixture of polyethylene glycols
 of the formula H(OCH.sub.2 CH.sub.2).sub.n OH, where n is an integer from
 7 to 10, PEG 600 is a mixture of polyethylene glycols of the formula
 H(OCH.sub.2 CH.sub.2).sub.n OH, where n is an integer from 11 to 16, and
 PEG 1000 is a mixture of polyethylene glycols of the formula H(OCH.sub.2
 CH.sub.2).sub.n OH, where n is an integer from 15 to 30. These mixtures
 can in each case be assigned a corresponding mean molecular weight of
 about 200 (PEG 200), about 400 (PEG 400), about 600 (PEG 600) or about
 1000 (PEG 1000).
 For the purposes of the present invention, M 350 is a mixture of compounds
 of the formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH, where n is an
 integer from 5 to 9, M 500 is a mixture of compounds of the formula
 CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH, where n is an integer from 9 to
 13, and M 750 is a mixture of compounds of the formula CH.sub.3 (OCH.sub.2
 CH.sub.2).sub.n OH, where n is an integer from 12 to 20. These mixtures
 can in each case be assigned a corresponding mean molecular weight of
 about 350 (M 350), about 500 (M 500) or about 750 (M 750).
 For the purposes of the present invention, 300 PR is a mixture of compounds
 of the formula R(OCH.sub.2 CH.sub.2).sub.n OH, where R is a
 .beta.-hydroxypropyl radical CH.sub.3 CHOHCH.sub.2 -- and n is an integer
 from 6 to 9, 450 PR is a mixture of compounds of the formula R(OCH.sub.2
 CH.sub.2).sub.n OH, where R is a .beta.-hydroxypropyl radical CH.sub.3
 CHOHCH.sub.2 -- and n is an integer from 8 to 14, 600 PR is a mixture of
 compounds of the formula R(OCH.sub.2 CH.sub.2).sub.n OH, where R is a
 .beta.-hydroxypropyl radical CH.sub.3 CHOHCH.sub.2 -- and n is an integer
 from 12 to 20, and 1000 PR is a mixture of compounds of the formula
 R(OCH.sub.2 CH.sub.2).sub.n OH, where R is a .beta.-hydroxypropyl radical
 CH.sub.3 CHOHCH.sub.2 -- and n is an integer from 18 to 26. These mixtures
 can in each case be assigned a corresponding mean molecular weight of
 about 300 (300 PR), about 450 (450 PR), about 600 (600 PR) or about 1000
 (1000 PR).
 In a number of cases it has been found to be useful to use a polyethylene
 glycol of the formula H(OCH.sub.2 CH.sub.2).sub.n OH, where n is an
 integer from 3 to 50, in particular from 4 to 30, preferably from 5 to 20,
 particularly preferably from 6 to 12, as the compound of the formula (1).
 It has also been found useful to use a compound (monoether) of the formula
 R(OCH.sub.2 CH.sub.2).sub.n OH, where R is a methyl radical or a
 .beta.-hydroxypropyl radical and n is an integer from 3 to 50, in
 particular from 4 to 30, preferably from 5 to 20, as the compound of the
 formula (1).
 It is also possible to use any mixtures of the compounds of the formula
 (1), namely polyethylene glycols, polyethylene glycol ethers (monoethers)
 and polyethylene glycol diethers.
 The reaction is carried out in the presence of hydrogen and carbon
 monoxide. The molar ratio of hydrogen to carbon monoxide can be selected
 within wide limits and is usually from 1:10 to 10:1, in particular from
 5:1 to 1:5, preferably from 2:1 to 1:2, particularly preferably from 1.2:1
 to 1:1.2. The process is particularly simple if hydrogen and carbon
 monoxide are used in a molar ratio of 1:1 or approximately 1:1.
 In many cases, it is sufficient to carry out the reaction at a temperature
 of from 50 to 150.degree. C., in particular from 100 to 140.degree. C.
 In many cases, it has been found to be useful to carry out the reaction at
 a pressure of from 10 to 200 bar, in particular from 20 to 150 bar,
 preferably from 30 to 80 bar.
 During the reaction, good mixing of organic phase, aqueous phase and carbon
 monoxide/hydrogen must be ensured. This can be effected, for example, by
 intensive stirring and/or pumped circulation of organic and aqueous
 phases. The organic phase usually comprises the olefinic compound, the
 aldehydes produced and also small amounts of the aqueous phase, while the
 aqueous phase usually comprises rhodium, the sulfonated triarylphosphines,
 the compound of the formula (1), water and small amounts of the organic
 phase.
 At this point, attention may again be drawn to the fact that the reaction
 conditions, in particular rhodium concentration, pressure and temperature,
 also depend on the type of olefinic compound to be hydroformylated.
 Comparatively reactive olefinic compounds require low rhodium
 concentrations, low pressures and low temperatures. In contrast, the
 reaction of relatively less reactive olefinic compounds requires higher
 rhodium concentrations, higher pressures and higher temperatures.
 The process can be carried out particularly successfully if an
 .alpha.-olefinic compound is used. However, other olefinic compounds
 containing internal carbon-carbon double bonds can also be reacted with
 good results.
 After the reaction is complete, the hydroformylation mixture is freed of
 carbon monoxide and hydrogen by depressurization and the reaction product,
 if appropriate after cooling, is separated from the aqueous phase
 comprising the catalyst and the compound of the formula (1) by phase
 separation.
 The aqueous phase comprising the catalyst and the compound of the formula
 (1) can be returned to the process of the invention, while the organic
 phase containing the reaction product is worked up, for example by
 fractional distillation.
 The process can be carried out continuously or batchwise.
 The following examples illustrate the invention without restricting it.
 EXPERIMENTAL T
 1. Hydroformylation of 1-pentene

EXAMPLE 1A)
 Comparative Experiment to Examples 1b) to 1d) without Addition of
 Polyethylene Glycol)
 I Preparation of the Catalyst Phase and Preformation
 60 mg (0.233 mmol) of rhodium(III) acetate are dissolved in 39 ml of a 0.6
 M aqueous solution of trisodium tri(m-sulfophenyl)phosphine (Na-TPPTS),
 corresponding to a molar ratio of rhodium to ligand of 1:100, and 21 ml of
 degassed distilled water and introduced under a stream of nitrogen into a
 200 ml steel autoclave. This catalyst solution is heated at 125.degree. C.
 under 25 bar of synthesis gas pressure (CO/H.sub.2 =1/1) for 3 hours while
 stirring, with the solution acquiring a yellow color.
 II Hydroformylation
 26.3 ml (240 mmol) of 1-pentene are added to the preformed catalyst
 solution from I at a reaction pressure of 30 bar and at 125.degree. C. via
 an upstream 200 ml steel autoclave using slight overpressure. The ratio of
 olefin to rhodium is 1039:1. The hydroformylation reaction is started by
 switching on the magnetic stirrer. During a reaction time of 3 hours, the
 temperature is held at 125.degree. C. and the reaction pressure is kept
 constant within a pressure band of .+-.2 bar by manual addition of
 synthesis gas. After 3 hours have elapsed, stirring and heating are
 switched off, the autoclave is cooled to from 40 to 50.degree. C. and the
 upper product phase is separated from the catalyst phase in a separating
 funnel. Product phase and catalyst phase are weighed. The composition of
 the product phase is determined by means of gas chromatography and .sup.1
 H-NMR spectroscopy, and the yield of hydroformylation products and the
 ratio of n-hexanal to iso-hexanal (2-methylpentanal) are determined from
 the composition. The rhodium content of the organic phase is, after
 digestion of the sample, determined by elemental analysis using
 graphite-furnace atomic absorption spectrometry. The yield of
 hydroformylation products is 49.4% and the n/iso ratio is 96:4. The
 organic phase contains 0.05 ppm of Rh. (Example 1a) in Table 1).
 EXAMPLE 1b)
 I Preparation of the Catalyst Phase and Preformation
 60 mg (0.233 mmol) of rhodium(III) acetate are dissolved in 39 ml of a 0.6
 M aqueous solution of trisodium tri(m-sulfophenyl)phosphine (Na-TPPTS). 5
 ml of degassed polyethylene glycol 400 are added to this solution and the
 solution is made up to the total volume of 60 ml. This catalyst phase is
 introduced under a stream of nitrogen into a 200 ml steel autoclave and is
 heated at 125.degree. C. under 25 bar synthesis gas pressure (CO/H.sub.2
 =1/1) for 3 hours while stirring.
 II Hydroformylation
 Using a method similar to Example 1a), 30 ml (240 mmol) of 1-hexene are
 added to the preformed catalyst solution from I. The hydroformylation is
 carried out using a method similar to Example 1a) at 125.degree. C. and 30
 bar of synthesis gas. The product phase is analyzed using a method similar
 to Example 1a). The yield of hydroformylation product is 70.1% and the
 n/iso ratio is 96:4.(Example 1b) in Table 1)
 EXAMPLE 1c)
 The procedure of Example 1b) is repeated, except that 7 ml of degassed
 polyethylene glycol 400 in place of 5 ml of degassed polyethylene glycol
 400 are now added to the catalyst phase and the total volume of the
 catalyst phase is made up to 60 ml. The preformation and hydroformylation
 conditions are identical to Example 1b). The yield of hydroformylation
 product is 81.1% and the n/iso ratio is 96:4. The organic phase contains
 0.16 ppm of Rh. (Example 1c) in Table 1)
 EXAMPLE 1d)
 The procedure of Example 1b) is repeated, except that 10 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase and the total
 volume of the catalyst phase is made up to 60 ml. The preformation and
 hydroformylation conditions are identical to Example 1b), except that the
 duration of the hydroformylation reaction is 210 min (3.5 hours). The
 yield of hydroformylation product is 88.0% and the n/iso ratio is 95:5.
 The organic phase contains 0.08 ppm of Rh. (Example 1d) in Table 1)
 EXAMPLE 1e)
 The procedure of Example 1b) is repeated, except that 21 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase. The preformation
 and hydroformylation conditions are identical to Example 1b). The yield of
 hydroformylation product is 87.3% and the n/iso ratio is 91:9. The organic
 phase contains 0.85 ppm of Rh. (Example 1e) in Table 1)
 EXAMPLE 1f)
 Without Addition of a Compound of the Formula (1)
 The procedure of Example 1a) is repeated, except that the hydroformylation
 reaction is carried out under 50 bar synthesis gas pressure. The yield of
 hydroformylation product is 74.8% and the n/iso ratio is 96:4. The organic
 phase contains 0.03 ppm of Rh. (Example 1f) in Table 1)
 EXAMPLE 1g)
 The procedure of Example 1f) is repeated, except that 5 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase and the total
 volume of the catalyst phase is made up to 60 ml. The preformation and
 hydroformylation conditions are identical to Example 1f). The yield of
 hydroformylation product is 84.9% and the n/iso ratio is 95:5. (Example
 1g) in Table 1)
 EXAMPLE 1h) (as EXAMPLE 1g)
 With a Longer Reaction Time
 The procedure of Example 1g) is repeated, except that the hydroformylation
 reaction is carried out for 240 min (4 hours). The yield of
 hydroformylation product is 88.4% and the n/iso ratio is 96:4. The organic
 phase contains 0.09 ppm of Rh (Example 1h) in Table 1)
 EXAMPLE 1i)
 The procedure of Example 1f) is repeated, except that 7 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase and the total
 volume of the catalyst phase is made up to 60 ml. The preformation and
 hydroformylation conditions are identical to Example 1f). The yield of
 hydroformylation product is 84.8% and the n/iso ratio is 95:5. (Example
 1i) in Table 1)
 EXAMPLE 1j)
 The procedure of Example 1f) is repeated, except that 10 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase and the total
 volume of the catalyst phase is made up to 60 ml. The preformation and
 hydroformylation conditions are identical to Example 1f). The yield of
 hydroformylation product is 87.5% and the n/iso ratio is 94:6. The organic
 phase contains 0.28 ppm of Rh (Example 1j) in Table 1)
 EXAMPLE 1k)
 Use of a Compound of the Formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH
 The procedure of Example 1g) is repeated, except that, in place of 5 ml of
 polyethylene glycol 400, the same volume (5 ml) of a compound of the
 formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH, n=5 to 9 (commercial
 product of Hoechst, designation M 350) is added to the catalyst phase and
 the total volume of the catalyst phase is made up to 60 ml. The
 preformation and hydroformylation conditions are identical to Example 1g).
 The yield of hydroformylation product is 84.3% and the n/iso ratio is
 95:5. The organic phase contains 0.07 ppm of Rh (Example 1k) in Table 1)
 EXAMPLE 1l)
 Use of a Compound of the Formula CH.sub.3 CHOHCH.sub.2 (OCH.sub.2
 CH.sub.2).sub.n OH (n=8 to 14
 The procedure of Example 1g) is repeated, except that, in place of 5 ml of
 polyethylene glycol 400 (PEG 400), the same volume (5 ml) of a compound of
 the formula CH.sub.3 CHOHCH.sub.2 (OCH.sub.2 CH.sub.2).sub.n OH, n=8 to 14
 (commercial product of Hoechst, designation 450PR) is added to the
 catalyst phase and the total volume of the catalyst phase is made up to 60
 ml. The preformation and hydroformylation conditions are identical to
 Example 1g). The yield of hydroformylation product is 84.0% and the n/iso
 ratio is 95:5. The organic phase contains 0.09 ppm of Rh (Example 1l) in
 Table 1)
 Examples 1g), 1k) and 1l) show that use of different compounds of the
 formula (1) gives comparable results in respect of yield of
 hydroformylation products, selectivity and rhodium content of the organic
 phase.
 EXAMPLE 1m)
 Use of a Compound of the Formula H(OCH.sub.2 CH.sub.2).sub.3 OH
 (triethylene glycol)
 The procedure of Example 1g) is repeated, except that, in place of 5 ml of
 polyethylene glycol 400 (PEG 400), the same volume of triethylene glycol
 is used and the total volume of the catalyst phase is made up to 60 ml.
 The preformation and hydroformylation conditions are identical to Example
 1g). The yield of hydroformylation product is 79.8% and the n/iso ratio is
 94:6. The organic phase contains 0.06 ppm of Rh (Example 1m) in Table 1)
 EXAMPLE 1n)
 Use of a Compound of the Formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n
 OCH.sub.3 (n=3 to 6)
 The procedure of Example 1g) is repeated, except that, in place of 5 ml of
 polyethylene glycol 400 (PEG 400), the same volume of a compound of the
 formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OCH.sub.3 (n=3 to 6,
 polyethylene glycol dimethyl ether) is used and the total volume of the
 catalyst phase is made up to 60 ml. The preformation and hydroformylation
 conditions are identical to Example 1g). The yield of hydroformylation
 product is 85.9% and the n/iso ratio is 95:5 (Example 1n) in Table 1)
 Experiments using compounds of the formula (4) as triarylphosphine ligands
 containing two phosphorus atoms
 EXAMPLE 1o)
 Comparative Example to Examples 1p) and 1q) without Addition of a Compound
 of the Formula (I)
 I Preparation of the Catalyst Phase and Preformation
 The catalyst phase is made up from 7.5 mg (0.028 mmol) of rhodium(III)
 acetate, 1.8 ml of a 0.162 molar solution of sulfonated
 2,2'-bis(diphenylphosphinomethyl)-1,1'-binaphthalene (Na-BINAS)
 corresponding to formula (4) and having a mean number of sulfonate groups
 of from 4 to 7, corresponding to a molar ratio of rhodium to ligand of
 1:10, and 58 ml of degassed distilled water and introduced under a stream
 of nitrogen into a 200 ml steel autoclave. This catalyst solution is
 heated at 125.degree. C. under 25 bar synthesis gas pressure (CO/H.sub.2
 =1/1) for 3 hours while stirring.
 II Hydroformylation
 The hydroformylation reation is carried out under a synthesis gas pressure
 of 50 bar and the work-up and analysis of the organic phase is carried out
 using a method similar to experiment 1f). The yield of hydroformylation
 products is 76.1% and the n/iso ratio is 98:2 (Example 1o) in Table 1)
 EXAMPLE 1p)
 The procedure of Example 1o) is repeated, except that 5 ml of degassed
 polyethylene glycol 400 are added to the catalyst phase and the total
 volume of the catalyst phase is made up to 60 ml. The yield of
 hydroformylation product is 76.1% and the n/iso ratio is 98:2 (Example 1p)
 in Table 1)
 EXAMPLE 1q)
 The procedure of Example 1o) is repeated, except that 10 ml of a compound
 of the formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH, n=9 to 13
 (commercial product of Hoechst, designation M 500) are added to the
 catalyst phase and the total volume of the catalyst phase is made up to 60
 ml. The yield of hydroformylation product is 75.7% and the n/iso ratio is
 98:2 (Example 1q) in Table 1)
 2. Hydroformylation of 1-butene
 EXAMPLE 2a)
 Comparative Experiment to Examples 2b) to 2g) without Addition of an
 Additive of the Formula (1)
 I Preparation of the Catalyst Phase and Preformation
 60 mg (0.233 mmol) of rhodium(III) acetate are dissolved in 39 ml of a 0.6
 M aqueous solution of trisodium tri(m-sulfophenyl)phosphine (Na-TPPTS),
 corresponding to a molar ratio of rhodium to ligand of 1:100, and 21 ml of
 degassed distilled water and introduced under a stream of nitrogen into a
 200 ml steel autoclave. The catalyst solution thus prepared is heated at
 125.degree. C. under 25 bar synthesis gas pressure (CO/H.sub.2 =1/1) for 3
 hours while stirring, with the solution acquiring a yellow color.
 II Hydroformylation
 12.46 g (224 mmol) of liquid 1-butene are added to the preformed catalyst
 solution from 1 at a reaction pressure of 30 bar and at 125.degree. C. via
 an upstream 200 ml steel autoclave using slight overpressure. (The precise
 amount is determined by difference weighing.) The ratio of olefin to
 rhodium is 950:1. The hydroformylation reaction is started by switching on
 the magnetic stirrer. During a reaction time the temperature is held at
 125.degree. C. and the reaction pressure is kept constant within a
 pressure band of .+-.2 bar by manual addition of synthesis gas. The
 reaction is stopped after 120 minutes since no more synthesis gas is
 absorbed. The stirrer and the heating are switched off, the autoclave is
 cooled to from 40 to 50.degree. C. and the upper product phase is
 separated from the catalyst phase in a separating funnel. The yield of
 hydroformylation products is determined by weighing and
 gas-chromatographic analysis of the organic phase; the ratio of n-pentanal
 to iso-pentanal (2-methylbutanal) is likewise determined by gas
 chromatography.
 In this series of examples, the duration of the hydroformylation reaction
 is a measure of the hydroformylation rate. In this example, it is 120
 minutes. The yield of hydroformylation products is 88.1% and the n/iso
 ratio is 96:4. The organic phase contains 0.07 ppm of Rh. (Example 2a) in
 Table 2)
 EXAMPLE 2b)
 I Preparation of the Catalyst Phase and Preformation
 60 mg (0.233 mmol) of rhodium(III) acetate are dissolved in 39 ml of a 0.6
 M aqueous solution of trisodium tri(m-sulfophenyl)phosphine (Na-TPPTS). 3
 ml of degassed polyethylene glycol 400 are added to this solution and the
 solution is made up to a total volume of 60 ml. This catalyst phase is
 introduced under a stream of nitrogen into a 200 ml steel autoclave and
 preformed at 125.degree. C. under 25 bar synthesis gas pressure
 (CO/H.sub.2 =1/1) for 3 hours while stirring.
 II Hydroformylation
 15.56 g (277 mmol) of 1-butene are added to the preformed catalyst solution
 from I, corresponding to a ratio of olefin to rhodium of 1186:1. The
 hydroformylation is carried out using a method similar to Example 2a) at
 125.degree. C. under 30 bar of synthesis gas. No further decrease in
 pressure occurs after 2 hours. The yield of hydroformylation product is
 87.2% and the n/iso ratio is 96:4. The organic phase contains 0.07 ppm of
 Rh. Thus, with the amount of 1-butene increased by 23.6%, 22% more
 1-butene is converted into hydroformylation products in the same reaction
 time without the n/iso selectivity being changed or the rhodium content of
 the organic phase rising. (Example 2b) in Table 2)
 EXAMPLE 2c)
 The catalyst phase is prepared and preformed using a method similar to
 Example 2a), except that 6 ml of degassed water are replaced by 6 ml of
 degassed polyethylene glycol. After the preformation, 13.34 g (238 mmol)
 of 1-butene are added, corresponding to a ratio of olefin to rhodium of
 1017:1. The reaction is complete after only 90 minutes. The yield of
 hydroformylation product is 85.9% and the n/iso ratio is 96:4. Thus,
 taking into account the increased amount of 1-butene and the decreased
 reaction time compared to Example 2a), 38% more 1-butene are converted
 into hydroformylation products per unit time than in Example 2a). (Example
 2c) in Table 1)
 Example 2d)
 The catalyst phase is prepared and preformed using a method similar to
 Example 2a), except that 9 ml of degassed water are replaced by 9 ml of
 degassed polyethylene glycol. After the preformation, 13.89 g (247 mmol)
 of 1-butene are added, corresponding to a ratio of olefin to rhodium of
 1058:1. The hydroformylation reaction is complete after only 60 minutes.
 The yield of hydroformylation product is 89.3% and the n/iso ratio is
 94:6. Thus, taking into account the increased amount of 1-butene and the
 decreased reaction time compared to Example 2a), 2.2 times as much
 1-butene is converted into hydroformylation products per unit time than in
 Example 2a). The rhodium content of the organic phase is 0.2 ppm (Example
 2d) in Table 2)
 EXAMPLE 2e)
 The catalyst phase is prepared and preformed using a method similar to
 Example 2a), except that 12 ml of degassed water are replaced by 12 ml of
 degassed polyethylene glycol 400. After the preformation, 13.57 g (242
 mmol) of 1-butene are added, corresponding to a ratio of olefin to rhodium
 of 1034:1. The hydroformylation reaction is complete after only 45
 minutes. The yield of hydroformylation product is 88.3% and the n/iso
 ratio is 94:6. Thus, taking into account the increased amount of 1-butene
 and the reduced reaction time compared Example 2a), 2.9 times as much
 1-butene is converted into hydroformylation products per unit time than in
 Example 2a). (Example 2e) in Table 2)
 EXAMPLE 2f)
 Use of a Compound of the Formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH,
 n=9 to 13
 The catalyst phase is prepared and preformed using a method similar to
 Example 2d), except that, in place of 9 ml of degassed polyethylene glycol
 400, the same volume of a compound of the formula CH.sub.3 (OCH.sub.2
 CH.sub.2).sub.n OH, n =9 to 13 (commercial product of Hoechst, designation
 M 500) is used. After the preformation, 13.52 g (241 mmol) of 1-butene are
 added, corresponding to a ratio of olefin to rhodium of 1031:1. The
 hydroformylation reaction is complete after 60 minutes. The yield of
 hydroformylation product is 87.1% and the n/iso ratio is 95:5. Thus,
 taking into account the increased amount of 1-butene and the reduced
 reaction time compared to Example 2a), 2.13 times as much 1-butene is
 converted into hydroformylation products per unit time than in Example
 2a). (Example 2f) in Table 2)
 EXAMPLE 2g)
 Use of a Compound of the Formula CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n
 OCH.sub.3, n=3 to 6
 The catalyst phase is prepared and preformed using a method similar to
 Example 2d), except that, in place of 9 ml of degassed polyethylene glycol
 400, the same volume of a compound of the formula CH.sub.3 (OCH.sub.2
 CH.sub.2).sub.n OCH.sub.3, n=3 to 6, is used. After the preformation,
 12.41 g (221 mmol) of 1-butene are added, corresponding to a ratio of
 olefin to rhodium of 946:1. The hydroformylation reaction is complete
 after 50 minutes. The yield of hydroformylation product is 85.9% and the
 n/iso ratio is 95:5. Thus, taking into account the reduced reaction time,
 40.0% more 1-butene is converted into hydroformylation products per unit
 time than in Example 2a). (Example 2g) in Table 2)
 3. Hydroformylation of Propene
 3.1 Description of the Experimental Apparatus
 The reaction apparatus used for the continuous hydroformylation of propene
 comprises a reactor (volume: 1l), a high-pressure separator connected
 downstream of the reactor and a phase separation vessel connected
 downstream of the high-pressure separator. During the hydroformylation,
 the reactor contains aqueous catalyst solution, unreacted propene,
 reaction products and synthesis gas. A stirrer installed in the reactor
 ensures good mixing.
 Propene and water are metered in through an immersed tube projecting into
 the reactor. The addition of water serves to replace the amounts of water
 which are carried off with the hydroformylation product and removed from
 the aqueous catalyst solution. The reaction mixture is removed from the
 reactor through an immersed tube dipping into the reactor and is fed to a
 high-pressure separator. In the high-pressure separator, the reaction
 mixture is separated into gaseous and liquid constituents. The gaseous
 constituents containing essentially unreacted synthesis gas, small amounts
 of propene and reaction products are discharged from the high-pressure
 separator and, after cooling, separated from the organic products in a
 further, downstream separator. The unreacted synthesis gas freed of the
 organic materials is, after recompression, returned to the reaction. The
 liquid constituents containing essentially the aqueous catalyst solution
 and the reaction mixture are taken from the high-pressure separator and
 fed to the phase separation vessel connected downstream of the
 high-pressure separator. In the phase separation vessel, separation of
 reaction product and aqueous catalyst solution occurs. The reaction
 product which forms the upper phase is separated off and subsequently
 distilled. The lower phase comprising the aqueous catalyst solution is
 taken from the phase separation vessel and returned to the reactor by
 means of a pump. In this way, the aqueous catalyst solution is circulated.
 3.2. Experimental Procedure
 EXAMPLE 3.2.a)
 Comparative Experiment without Addition of polyethylene glycol 400
 The aqueous catalyst solution comprises 200 ppm of rhodium, trisodium
 tri(m-sulfophenyl)phosphine (Na-TPPTS) and rhodium in a molar ratio of
 100:1. It is prepared by dissolving the corresponding amount of
 rhodium(III) acetate in an aqueous Na-TPPTS solution and preforming the
 catalyst solution at 122.degree. C. under the conditions of the
 hydroformylation in the presence of synthesis gas (CO/H.sub.2 =1/1). The
 reactor (volume: 1) equipped with a stirrer is 65% full of catalyst
 solution (650 ml) in the operating state. The total volume of catalyst
 solution is 850 ml, i.e. 200 ml of catalyst solution are present in the
 circulation system (high-pressure separator, phase separation vessel and
 lines) connected downstream of the reactor 83.5 g/h of propene and 0.0955
 standard cubic meters per hour of synthesis gas are fed continuously to
 the reactor. The pressure is 50 bar and the reaction temperature is
 122.degree. C. The contents of the reactor are mixed vigorously by means
 of the stirrer. The mean residence time of the catalyst solution is 0.43
 h.sup.-1. The catalyst solution separated off in the phase separation
 vessel (1.5 l/h) is returned to the reactor. The propene conversion is
 90%. This corresponds to a productivity of 0.2 kg of crude
 hydroformylation product per l of catalyst solution and hour (0.2 kg/(l of
 cat..times.h)). The ratio of n-butyraldehyde to 2-methylpropanal is 93:7.
 EXAMPLE 3.2.b)
 Hydroformylation of Propene with Addition of polyethylene glycol 400
 The procedure of Comparative Experiment 3.2.a) is repeated, except that the
 aqueous catalyst solution contains 9.5% by weight of polyethylene glycol
 having a mean molecular weight of 400 (PEG 400), the propene feed is
 increased to 100 g/h and the amount of synthesis gas is increased to 0.102
 standard cubic meters per hour.
 The propene conversion is now from 95% to 96%. This corresponds to a
 productivity of 0.25 kg of crude hydroformylation product per l of
 catalyst solution and hour (0.25 kg/(l of cat..times.h)). The ratio of
 n-butyraldehyde to 2-methylpropanal is 91:9.
 TABLE 1
 Hydroformylation of 1-pentene
 Constant conditions: T = 125.degree. C., 240 mmol of olefin, total volume
 of catalyst phase = 60 ml
 Additive
 Pressure Yield Rh
 Example Olefin:Rh Ligand Type Amount [ml] % by weight.sup.1 P:Rh
 [bar] T [.degree. C.] t [min] % n/iso.sup.2 [ppm].sup.3
 1a) 1039 TPPTS -- -- -- 100:1 30 125
 180 49.4 96:4 0.05
 1b) 1039 TPPTS .sup. PEG.sup.4 5 8.7
 100:1 30 125 180 70.1 96:4 n.d.
 1c) 1039 TPPTS PEG 7 12.2 100:1 30
 125 180 81.1 96:4 0.16
 1d) 1039 TPPTS PEG 10 17.2 100:1 30
 125 210 88.0 95:5 0.08
 1e) 1039 TPPTS PEG 21 35.0 100:1 30
 125 180 87.3 91:9 0.85
 1f) 1039 TPPTS PEG -- -- 100:1 50 125
 180 74.8 96:4 &lt;0.03
 1g) 1039 TPPTS PEG 5 8.7 100:1 50
 125 180 84.9 95:5 n.d.
 1h) 1039 TPPTS PEG 5 8.7 100:1 50
 125 240 88.4 96:4 0.09
 1i) 1039 TPPTS PEG 7 12.2 100:1 50
 125 180 84.8 95:5 n.d.
 1j) 1039 TPPTS PEG 10 17.2 100:1 50
 125 180 87.5 94:6 0.28
 1k) 1039 TPPTS M 350.sup.5 5 8.7 100:1
 50 125 180 84.3 95:5 0.07
 1l) 1039 TPPTS 450 PR.sup.6 5 8.7 100:1
 50 125 180 84.0 95:5 0.09
 1m) 1039 TPPTS TEG.sup.7 5 8.7 100:1 50
 125 180 79.8 94:6 0.06
 1n) 1039 TPPTS DMPEG.sup.8 5 8.7 100:1
 50 125 180 76.3 95:05:00 n.d.
 1o) 5000 BINAS PEG -- -- 10:1 50 125
 180 59.5 99:1 n.d.
 1p) 5000 BINAS PEG 5 10:1 50
 125 180 76.1 98:2 n.d.
 1q) 5000 BINAS M 500.sup.9 10 10:1 50
 125 180 75.7 98:2 n.d.
 .sup.1 % by weight of additive based on the catalyst phase
 .sup.2 Ratio of n-hexanal to 2-methylpentanal (iso-hexanal)
 .sup.3 Rhodium content of the organic phase
 .sup.4 PEG = PEG 400 = H(OCH.sub.2 CH.sub.2).sub.n OH; n = 7 to 10
 .sup.6 450 PR = CH.sub.3 CHOHCH.sub.2 (OCH.sub.2 CH.sub.2).sub.n, n = 8 to
 14
 .sup.7 TEG = H(OCH.sub.2 CH.sub.2).sub.3 OH
 .sup.8 DMPEG = CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OCH.sub.3 ; n = 3 to 6
 .sup.9 M 500 = CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH; n = 9 to 13
 TABLE 2
 Hydroformylation of 1-butene
 Constant conditions: pressure = 50 bar, T = 125.degree. C.,
 use of TPPTS as ligand in a TPPTS:Rh ratio of 100:1, total volume of
 catalyst phase = 60 ml
 Additive
 Rh R.sub.r
 Example 1-butene [mmol] Olefin:Rh Type Amount [ml] % by weight.sup.1
 t [min] Yield % n/iso.sup.2 [ppm].sup.3 [mmol/min].sup.4
 2a) 224 950:1 -- -- -- 120 88.1 96:4
 0.07 1644
 2b) 277 1186:1 .sup. PEG.sup.5 3 5
 120 87.2 96:4 0.07 2013
 2c) 238 1017:1 PEG 6 10 90
 85.9 96:4 0.1 2272
 2d) 247 1058:1 PEG 9 16 60
 89.3 94:6 0.2 3676
 2e) 242 1034:1 PEG 12 21 45
 88.3 94:6 0.16 4746
 2f) 241 1030:1 M 500.sup.6 9 16
 60 87.1 95:5 n.d. 3545
 2g) 221 946:1 DMPEG.sup.7 9 16 50
 85.9 95:6 n.d. 2308
 .sup.1 % by weight of additive based on the catalyst phase
 .sup.2 Ratio of n-pentanalto 2-methylbutanal (iso-pentanal)
 .sup.3 Rhodium content of the organic phase
 .sup.4 Mean reaction rate defined as mmol of aldehyde formed per minute of
 reaction time.
 .sup.5 PEG = PEG 400 = H(OCH.sub.2 CH.sub.2).sub.n OH; n = 7 to 10
 .sup.6 M 500 = CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OH; n = 9 to 13
 .sup.7 DMPEG = CH.sub.3 (OCH.sub.2 CH.sub.2).sub.n OCH.sub.3 ; n = 3 to 6