DE10260797A1 - Heterocyclic monopnicogen compounds, useful as ligands for metal complex catalysts e.g. for hydroformylation, particularly production of 2-propylheptanol are new - Google Patents

Abstract

Heterocyclic monopnicogen compounds (I) are new. Heterocyclic monopnicogen compounds of formula (I) are new : R1-Pn(R2)-(O)a-Y-OR3 (I) Pn = a pnicogen atom, i.e. phosphorus, arsenic or antimony; R1 = pyrrole bound to Pn through the N atom; R2 = alkyl, alkoxy, aryl, aryloxy, (hetero)cycloalkyl, (hetero)cycloalkoxy, pyrrole bound to Pn through the N atom or a different heteroaryl, or R1 and R2 are together a divalent heteroatom-containing group that includes at least one pyrrole bound to Pn through the N atom; a = 0 or 1; Y = divalent bridging group of 2-10 atoms; R3 = hydrogen, alkyl, aryl, (hetero)cycloalkyl, heteroaryl or silyl. Independent claims are also included for; (1) A catalyst (A) comprising a complex of a metal of subgroup VIII that contains at least one (I) as ligand; (2) A method for hydroformylation of ethylenically unsaturated compounds by reaction with carbon monoxide and hydrogen in presence of (A); (3) A method for preparing 2-propylheptanol by converting a butene (or C4 fraction containing it) as in (2), then aldol condensation of the n-valeraldehyde formed and catalytic hydrogenation; and (4) A method for preparing an ester mixture by reacting the alcohol mixture from (3) with at least one acid.

Description

The present invention relates to new monopnicogen compounds, catalysts that have at least one Complex of a metal of subgroup VIII with at least one such monopnicogen compound as ligands, a method for hydroformylation and a process for the preparation of 2-propylheptanol using these catalysts and other uses of these Catalysts.

Hydroformylation or oxo synthesis is an important large-scale Process and used for the production of aldehydes from olefins, Carbon monoxide and hydrogen. These aldehydes can optionally be in the same Work with hydrogen to the corresponding oxo alcohols be hydrogenated. The reaction itself is highly exothermic and generally runs under elevated Pressure and at elevated Temperatures in the presence of catalysts. As catalysts become Co, Rh, Ir, Ru, Pd or Pt compounds or complexes used for activity and / or influencing selectivity can be modified with N- or P-containing ligands. at the hydroformylation reaction of olefins with more than two carbon atoms it can because of the possible CO addition to each of the two carbon atoms of a double bond for formation come from mixtures of isomeric aldehydes. In addition, it can be used of olefins with at least four carbon atoms also to one Double bond isomerization will occur, i.e. H. to a shift internal double bonds to a terminal position and vice versa.

Because of the much larger technical Meaning of α-aldehydes will achieve optimization of the hydroformylation catalysts one if possible high hydroformylation activity at the same time if possible low tendency to form non-α-permanent Double bonds sought. Thus there is a need for hydroformylation catalysts which also starting from internal linear olefins or olefin mixtures, which contain internal olefins in sufficient yields to α-and especially n-standing Lead aldehydes. Here, the catalyst must both establish an equilibrium between internal and terminal double bond isomers as well preferably selectively enable the hydroformylation of the terminal olefins.

For example, for the production of ester plasticizers with good performance properties, there is a need for plasticizer alcohols with about 6 to 12 carbon atoms, which are branched to a small extent (so-called semi-linear alcohols) and for corresponding mixtures thereof. These include, in particular, 2-propylheptanol and alcohol mixtures containing it. For their preparation, for example, C ₄ -hydrocarbon mixtures which contain butenes or butenes and butanes can be subjected to hydroformylation and subsequent aldol condensation. When using hydroformylation catalysts with insufficient n-selectivity, hydroformylation can easily lead not only to the formation of n-valeraldehyde but also to undesired product aldehydes, which economically disadvantages the entire process. Another requirement that is placed on hydroformylation catalysts is good stability, both under the hydroformylation conditions and during workup, since catalyst losses have a particularly negative effect on the economy of the corresponding process.

It is known in low pressure rhodium hydroformylation phosphorus-containing ligands for stabilization and / or activation of the catalyst metal. Suitable phosphorus-containing ligands are z. B. phosphines, phosphinites, phosphonites, phosphites, phosphoramidites, Phospholes and phosphabenzenes. The most widely used at the moment Ligands are triarylphosphines, such as. B. triphenylphosphine and sulfonated triphenylphosphine, as this under the reaction conditions sufficient stability have. A disadvantage of these ligands, however, is that in general only very high ligand excesses satisfactory Deliver yields in particular of linear aldehydes.

WO 00/56451 relates to the phosphorus atom including cyclic oxaphosphorines substituted with pyrrole derivatives and the use of these as ligands in hydroformylation catalysts.

WO 01/58589 describes compounds of phosphorus, arsenic and antimony based on diaryl-fused Bicyclo [2.2.2] foundations and Catalysts that contain these as ligands.

The DE-A-100 23 471 describes a process for hydroformylation using a hydroformylation catalyst which comprises at least one phosphine ligand which has two triarylphosphine groups, one aryl radical of each of the two triarylphosphine groups being bonded via a single bond to a non-aromatic 5- to 8-membered carbocyclic or heterocyclic bridging group. The phosphorus atoms can also have, among other things, hetaryl groups as further substituents.

The DE-A-100 46 026 describes a hydroformylation process in which a catalyst is used Complex based on a phosphorus, arsenic or antimony-containing compound is used as the ligand, this compound each having two groups having a P, As or Sb atom and at least two further heteroatoms, bonded to a xanthene-like molecular structure ,

The unpublished international application PCT / EP02 / 09455 describes a hydroformylation process using a catalyst complex which has as ligands at least one pyrrole-phosphorus compound in which a substituted and / or pyrrole group integrated in a fused ring system is covalently linked to the phosphorus atom via its pyrrole nitrogen atom.

The unpublished German patent application P 102 05 361.8 describes phosphorus chelate compounds in which three nitrogen atoms, which are themselves part of an aromatic ring system, are covalently bonded to the two phosphorus atoms and their use as ligands for hydroformylation catalysts.

The unpublished German patent application P 102 43 138.8 describes pnicogen compounds which have two pnicogen atoms, heteroatoms which are themselves bound to both pnicogen atoms and which are themselves part of a ring system and where both pnicogen atoms are bonded to a bridging group via C ₁ fragments.

The international registration PCT / EP02 / 03543 describes, inter alia, a process for the hydroformylation of olefins using a hydroformylation catalyst which comprises a complex of a metal from subgroup VIII with at least one pnicogen chelate compound as ligand. These ligands have two groups containing pnicogen atoms which are connected to one another via a xanthene-like or triptycene-like molecular structure and where at least one pyrrole group is covalently bonded to each pnicogen atom via its nitrogen atom.

W. Goertz et al. describe in J. Chem. Soc., Dalton Trans., 1998, pp. 2981-2988 chelate ligands with xanthene-like backbones, which among other things have two phosphonite groups covalently bonded to the backbone and their use for the nickel-catalyzed hydrocyanation of Styrene.

WO 98/43935 describes monodentate and bidentate phosphonite ligands and their use in hydroformylation catalysts. Phosphorus chelate compounds in which the phosphorus atoms are connected to one another via a bridge group with at least one cyclic structural element and both phosphorus atoms are bonded to the bridge group on the one hand via optionally substituted methylene groups (C ₁ groups) and on the other hand two heteroatoms are bonded to both phosphorus atoms, which are themselves Are part of a ring system are not described in this document.

In "Applied Homogeneous Catalysis with Organometallic Compounds ", volume 1, pp. 86-87, VCH Weinheim, the use of (2,2'-bis (dibenzophospholylmethyl) -1,1'-biphenyl) and (2,2'-bis (dibenzophospholylmethyl) -5,5'-di-tert-butyl-1 , 1'-biphenyl) as ligands described for hydroformylation.

The US 4,774,362 describes chelate phosphines with 1,2-dialkylene benzene backbones and their use as ligands for hydroformylation catalysts.

The US 4,904,808 describes chelate phosphines with 2,2'-bismethylene-1,1'-biphenyl backbones and their use as ligands in catalysts for low-pressure hydroformylation.

The US 5,288,912 describes a process for the preparation of alkyl (diaryl) phosphine compounds, which can also be bridged.

The US 5,347,045 describes sulfonated 2,2'-bis (diphenylphosphinomethyl) -1,1'-binaphthylenes and their use as ligands in hydroformylation catalysts.

The US 6,043,398 describes water-soluble, sulfonated, bridged aryldiphosphines and catalysts which contain these as ligands.

The DE-A-195 32 393 describes a process for the hydroformylation of olefinically unsaturated compounds in a homogeneous phase in a polar organic solvent and in the presence of a catalyst system which consists of a rhodium carbonyl compound and the salt of a sulfonated or carboxylated organic phosphine. These phosphines preferably have 2,2'-bismethylene-1,1'-biphenyl or 2,2'-bismethylene-1,1'-binaphthyl backbones.

The present invention lies based on the task of making new pnicogen compounds available represent themselves as ligands for transition metal complexes of metals of subgroup VIII. are suitable for new catalysts based on these metal complexes. Preferably these ligands should be easy to prepare and / or their complexes under the reaction conditions of the reactions to be catalyzed preferably be stable and have good catalytic activity. It should at the hydroformylation of olefins with internal double bonds or of olefin mixtures containing such olefins, preferably one if possible high proportion of n-aldehydes or alcohols (n-selectivity) can be achieved.

gefunden, worin
Pn für ein Pnicogenatom, ausgewählt aus den Elementen Phosphor, Arsen oder Antimon steht,
R¹ für eine über das pyrrolische Stickstoffatom an das Pnicogenatom gebundene Pyrrolgruppe steht,
R² für Alkyl, Alkoxy, Aryl, Aryloxy, Cycloalkyl, Cycloalkoxy, Heterocycloalkyl, Heterocycloalkoxy, eine über das pyrrolische Stickstoffatom an das Pnicogenatom gebundene Pyrrolgruppe oder eine davon verschiedene Hetarylgruppe steht, oder
R¹ gemeinsam mit R² eine zweibindige heteroatomhaltige Gruppe bildet, die wenigstens eine über das pyrrolische Stickstoffatom an das Pnicogenatom gebundene Pyrrolgruppe enthält,
a die Zahl 0 oder 1 bedeutet,
Y für eine zweiwertige verbrückende Gruppe mit 2 bis 10 Brückenatomen zwischen den flankierenden Bindungen steht, und
R³ für Wasserstoff, Alkyl, Aryl, Cycloalkyl, Heterocycloalkyl, Hetaryl oder Silyl steht.Accordingly, monopnicogen compounds of the general formula I

found what
Pn stands for a pnicogen atom selected from the elements phosphorus, arsenic or antimony,
R ^{1 represents} a pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom,
R ^{2 represents} alkyl, alkoxy, aryl, aryloxy, cycloalkyl, cycloalkoxy, heterocycloalkyl, heterocycloalkoxy, a pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom or a hetaryl group different therefrom, or
R ¹ together with R ² forms a double-bonded heteroatom-containing group which contains at least one pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom,
a means the number 0 or 1,
Y represents a divalent bridging group with 2 to 10 bridge atoms between the flanking bonds, and
R ^{3 represents} hydrogen, alkyl, aryl, cycloalkyl, heterocycloalkyl, hetaryl or silyl.

In addition, the present concerns Invention catalysts comprising complexes with a metal of VIII. Subgroup of the Periodic Table of the Elements, which are at least ligands contain a monopnicogen compound of the general formula I.

The present invention further provides a process for the hydroformylation of compounds which contain at least one ethylenically unsaturated double bond and, in particular, a process for the preparation of aldehydes and / or alcohols by the hydroformylation of C ₃ -C ₂₀ -olefins, preferably of C ₄ - C ₂₀ olefins, at elevated pressure and elevated temperature by means of CO / H ₂ mixtures in the presence of a metal complex compound of a metal from VIII. Subgroup homogeneously dissolved in the reaction medium. Subgroup of the Periodic Table of the Elements as catalyst and free ligand, in which pnicogen complexes and uses monopnicogen compounds of the general formula I as free ligands.

Another object of the invention is a process for the preparation of 2-propylheptanol that undergoes hydroformylation of butene, an aldol condensation of the hydroformylation products thus obtained and the subsequent one Hydrogenation of the condensation products comprises, being as a hydroformylation catalyst a complex of a metal of subgroup VIII with at least one Monopnicogen compound of general formula I used as ligands becomes.

For the purpose of explaining the present invention, the term "alkyl" includes straight-chain and branched alkyl groups. These are preferably straight-chain or branched C ₁ -C ₂₀ alkyl, preferably C ₁ -C ₁₂ alkyl, particularly preferably C ₁ -C ₈ alkyl and very particularly preferably C ₁ -C ₄ alkyl groups Examples of alkyl groups are in particular methyl, ethyl, propyl, isopropyl, n-butyl, 2-butyl, sec-butyl, tert-butyl, n -Pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 2-hexyl, 2-methylpentyl, 3 -Methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl , 1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, n-heptyl, 2-heptyl, 3-heptyl, 2-ethylpentyl, 1-propylbutyl, n-octyl, 2nd -Ethylhexyl, 2-propylheptyl, nonyl, decyl.

The term “alkyl” also includes substituted alkyl groups which generally have 1, 2, 3, 4 or 5, preferably 1, 2 or 3 and particularly preferably 1, substituents selected from the groups cycloalkyl, aryl, hetaryl, halogen, NE ¹ E ² , NE ¹ E ² E ³⁺ , carboxyl, carboxylate, -SO ₃ H and sulfonate, preferred substituted alkyl radicals are also perfluoroalkyl radicals, especially trifluoromethyl.

The term “alkylene” in the sense of the present invention stands for straight-chain or branched alkanediyl groups with 1 to 4 carbon atoms.

For the purposes of the present invention, the term “cycloalkyl” embraces unsubstituted and substituted cycloalkyl groups, preferably C ₅ -C ₇ cycloalkyl groups, such as cyclopentyl, cyclohexyl or cycloheptyl, which, in the case of a substitution, are generally 1, 2, 3, 4 or 5 , preferably 1, 2 or 3 and particularly preferably 1 substituents selected from the groups alkyl, alkoxy and halogen.

The term “heterocycloalkyl” in the context of the present invention encompasses saturated, cycloaliphatic groups with generally 4 to 7, preferably 5 or 6 ring atoms, in which 1 or 2 of the ring carbon atoms are replaced by heteroatoms selected from the elements oxygen, nitrogen and sulfur and which may optionally be substituted, where in the event of a substitution these heterocycloaliphatic groups 1, 2 or 3, preferably 1 or 2, particularly preferably 1, selected from alkyl, aryl, COOR ^f , COO ^- M ⁺ and NE ¹ E ² Examples of such heterocycloaliphatic groups are pyrrolidinyl, piperidinyl, 2,2,6,6-tetramethyl-piperidinyl, imidazolidinyl, pyrazolidinyl, oxazolidinyl, morpholidinyl, thiazolidinyl, isothiazolidinyl, isoxazolidinyl, piperazinyl, tetrahydrothiophenyl Tetrahydropyranyl, called dioxanyl.

For the purposes of the present invention, the term “aryl” comprises unsubstituted and substituted aryl groups, and preferably stands for phenyl, tolyl, xylyl, mesityl, duryl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl or naphthacenyl, particularly preferably for phenyl or naphthyl, where these Aryl groups in the case of substitution generally 1, 2, 3, 4 or 5, preferably 1, 2 or 3 and particularly preferably 1 substituents selected from the groups alkyl, alkoxy, carboxyl, carboxylate, trifluoromethyl, -SO ₃ H, sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² , nitro, cyano or halogen.

For the purposes of the present invention, the term “hetaryl” encompasses unsubstituted or substituted heterocycloaromatic groups, preferably the groups pyridyl, quinolinyl, acridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, and also the subgroup of the “pyrrole group”, these heterocycloaromatic groups being substituted in the Generally 1, 2 or 3 substituents selected from the groups alkyl, alkoxy, carboxyl, carboxylate, -SO ₃ H, sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² , trifluoromethyl or halogen.

For the purposes of the present invention, the term “pyrrole group” stands for a series of unsubstituted or substituted, heterocycloaromatic groups which are structurally derived from the pyrrole backbone and contain a pyrrolic nitrogen atom in the heterocycle which can be covalently linked to other atoms, for example a pnicogen atom The term "pyrrole group" thus includes the unsubstituted or substituted groups pyrrolyl, imidazolyl, pyrazolyl, indolyl, purinyl, indazolyl, benzotriazolyl, 1,2,3-triazolyl, 1,3,4-triazolyl and carbazolyl, which in the case of substitution in general 1, 2 or 3, preferably 1 or 2, particularly preferably 1 substituent, selected from the groups alkyl, alkoxy, acyl, carboxyl, carboxylate, -SO ₃ H, sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² , trifluoromethyl or halogen.

als Beispiel für eine Bispyrrolgruppe, die zwei direkt verknüpfte Pyrrolgruppen, in diesem Falle Indolyl, enthält, oder die Bispyrroldiylmethan-Gruppe der Formel

als Beispiel für eine Bispyrrolgruppe, die zwei über eine Methylengruppe verknüpfte Pyrrolgruppen, in diesem Falle Pyrrolyl, enthält. Wie die Pyrrolgruppen können auch die Bispyrrolgruppen unsubstituiert oder substituiert sein und im Falle einer Substitution pro Pyrrolgruppeneinheit im Allgemeinen 1, 2 oder 3, vorzugsweise 1 oder 2, insbesondere 1 Substituenten, ausgewählt aus Alkyl, Alkoxy, Carboxyl, Carboxylat, -SO₃H, Sulfonat, NE¹E², Alkylen-NE¹E², Trifluormethyl oder Halogen, tragen, wobei bei diesen Angaben zur Anzahl möglicher Substituenten die Verknüpfung der Pyrrolgruppeneinheiten durch direkte chemische Bindung oder durch die mittels der vorstehend genannten Gruppen vermittelte Verknüpfung nicht als Substitution betrachtet wird.Accordingly, the term “bispyrrole group” in the context of the present invention includes double-bonded groups of the formula Py-I-Py, wherein Py stands for a pyrorole group, as defined in the introduction, which contain two linked pyrrole groups, such as the bisindoldiyl group of the formula, which are linked by direct chemical bonding or alkylene, oxa, thio, imino, silyl or alkylimino groups

as an example of a bispyrrole group which contains two directly linked pyrrole groups, in this case indolyl, or the bispyrroldiylmethane group of the formula

as an example of a bispyrrole group which contains two pyrrole groups linked via a methylene group, in this case pyrrolyl. Like the pyrrole groups, the bispyrrole groups can also be unsubstituted or substituted and, in the case of substitution per pyrrole group unit, generally 1, 2 or 3, preferably 1 or 2, in particular 1, substituents selected from alkyl, alkoxy, carboxyl, carboxylate, -SO ₃ H, Sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² , trifluoromethyl or halogen, wear, with this information on the number of possible substituents, the linkage of the pyrrole group units by direct chemical bond or by the linkage mediated by the above groups is not considered a substitution becomes.

In the context of this invention, carboxylate and sulfonate preferably represent a derivative of a carboxylic acid function or a sulfonic acid function, in particular a metal carboxylate or sulfonate, a carboxylic acid or sulfonic acid ester function or a carboxylic acid or sulfonic acid amide function. These include e.g. B. the esters with C ₁ -C ₄ alkanols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert-butanol.

The above explanations of the terms "alkyl", "cycloalkyl", "aryl", "heterocycloalkyl" and "hetaryl" apply accordingly for the Terms "alkoxy", "cycloalkoxy", "aryloxy", "heterocycloalkoxy" and "hetaryloxy".

The term "acyl" is used for the purposes of the present invention for alkanoyl or aroyl groups with generally 2 to 11, preferably 2 to 8 carbon atoms, for example for the acetyl, propanoyl, Butanoyl, pentanoyl, hexanoyl, heptanoyl, 2-ethylhexanoyl, 2-propylheptanoyl, benzoyl or naphthoyl group.

The groups NE ¹ E ² , NE ⁴ E ⁵ , NE ⁶ NE ⁷ and NE ⁹ NE ¹⁰ preferably represent N, N-dimethylamino, N, N-diethylamino, N, N-dipropylamino, N, N-diisopropylamino, N, N-di-n-butylamino, N, N-di-tert-butylamino, N, N-dicyclohexylamino or N, N-diphenylamino.

Halogen stands for fluorine, chlorine, bromine and iodine, preferred for Fluorine, chlorine and bromine.

The term "silyl" stands for triple substituted silicon atom groups, preferably trialkylsilyl, such as trimethylsilyl, and triarylsilyl, such as triphenylsilyl.

M ⁺ stands for a cation equivalent, ie for a monovalent cation or the part of a multivalent cation corresponding to a positive single charge. The cation M ⁺ serves only as a counterion for the neutralization of negatively charged substituent groups, such as the COO ^- or the sulfonate group, and can be found in the prin zip can be chosen arbitrarily. Alkali metal ions, in particular Na ⁺ , K ⁺ , Li ⁺ ions or onium ions, such as ammonium, mono-, di-, tri-, tetraalkylammonium, phosphonium, tetraalkylphosphonium or tetraarylphosphonium ions are therefore preferably used.

The same applies to the anion equivalent X ^- , which only serves as a counterion of positively charged substituent groups, such as the ammonium groups, and can be chosen arbitrarily from monovalent anions and the proportions of a multivalent anion corresponding to a negative single charge.

The values for x represent a whole Number from 1 to 240, preferably for an integer from 3 to 120.

Condensed ring systems can Annulation linked (Condensed) aromatic, hydroaromatic and cyclic compounds his. Condensed ring systems consist of two, three or more than three rings. A distinction is made depending on the type of link in the case of condensed ring systems between ortho annulation, i.e. H. each ring has one edge or two with each neighboring ring Atoms common, and a peri-annulation, in which a carbon atom listened to more than two rings. Preferred among the condensed ring systems are ortho-condensed ones Ring systems.

It was found that pnicogen compounds, which contains a group containing pnicogen atoms and additionally a group containing oxygen atoms Have group, both at different terminal ends of one bridging Group, are particularly advantageously suitable as ligands for hydroformylation catalysts, especially for Catalysts for the isomerizing hydroformylation of olefins with internal Double bonds. They are preferably pnicogen compounds, where at least two of the bridge atoms the bridging Group Y are part of an alicyclic or aromatic group.

Pn stands for an atom from the pnicogen group, selected from phosphorus, arsenic or antimony. Pn particularly preferably represents phosphorus.

The pnicogen atom Pn of the monopnicogen compounds according to the invention is in each case connected to the substituents R ¹ and R ² via two covalent bonds, where R1 represents a pyrrole group bonded to the picnicogen atom via the pyrrolic nitrogen atom and R ^{2 represents} alkyl, alkoxy, aryl, aryloxy, cycloalkyl, Cycloalkoxy or a hetaryl group. The substituent R ² advantageously also represents a pyrrole group bonded to the pnicogen atom Pn via the pyrrolic nitrogen atom.

worin
Alk eine C₁-C₄-Alkylgruppe ist,
R^α eine C₁-C₄-Alkylgruppe oder eine Arylgruppe ist, und
R^g, R^h, Rⁱ und R^k unabhängig voneinander für Wasserstoff, C₁-C₄-Alkyl, C₁-C₄-Alkoxy, Acyl, Halogen, Trifluormethyl, C₁-C₄-Alkoxycarbonyl oder Carboxyl stehen.At least one of the radicals R ¹ and R ^{2 is} preferred, and preferably R ¹ and R ^{2 are} both independently selected from groups of the formulas Ia to Ik:

wherein
Alk is a C ₁ -C ₄ alkyl group,
R ^{α is} a C ₁ -C ₄ alkyl group or an aryl group, and
R ^g , R ^h , R ⁱ and R ^k independently represent hydrogen, C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, acyl, halogen, trifluoromethyl, C ₁ -C ₄ alkoxycarbonyl or carboxyl.

Some advantageous pyrrole groups are listed below for illustration purposes:

The 3-methylindolyl group is particularly advantageous (Skatolyl group) of formula I.fl. hydroformylation based on ligands containing one or two 3-methylindolyl group (s) have bound to the phosphorus atom, are characterized by a particularly high stability and thus a particularly long catalyst life.

In a further advantageous embodiment of the present invention, the substituent R ¹ together with the substituent R ² can contain a divalent group of the formula containing pyrrole group bonded to the pnicogen atom Pn via the pyrrolic nitrogen atom Py-IW form,
wherein
Py is a pyrrole group
I represents a chemical bond or O, S, SiR ^ε R ^ζ , NR ^η or optionally substituted C ₁ -C ₁₀ alkylene, preferably CR ^λ R ^μ ,
W represents cycloalkyloxy or amino, aryloxy or amino, hetaryloxy or amino and
R ^ε , R ^ζ , R ^η , R ^λ and R ^μ independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
the designations used here have the meaning explained at the beginning.

Preferred divalent groups of the formula Py-IW are z. B.

bildet, worin
I für eine chemische Bindung oder für O, S, SiR^εR^ζ,NR^η oder gegebenenfalls substituiertes C₁-C₁₀-Alkylen, bevorzugt CR^λR^μ, steht, worin R^ε, R^ζ, R^η, R^λ und R^μ unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl oder Hetaryl stehen,
R⁵, R^5', R⁶, R^6', R⁷, R^7', R⁸ und R^8' unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl, Hetaryl, WCOOR^°, WCOO^–M⁺, W(SO₃)R^°, W(SO₃)^–M⁺, WPO₃(R^°)(R^p), W(PO₃)^2–(M⁺)₂, WNE¹E², W(NE¹E²E³)⁺X^–, WOR^°, WSR^°, (CHR^°CH₂O)_xR^°, (CH₂NE¹)_xR^°, (CH₂CH₂NE¹)_xR^°, Halogen, Perfluoralkyl, vorzugsweise Trifluormethyl, Nitro, Acyl oder Cyano stehen, worin
W für eine Einfachbindung, ein Heteroatom, eine Heteroatom-haltige Gruppe oder eine zweiwertige verbrückende Gruppe mit 1 bis 20 Brückenatomen steht,
R^°, E¹, E², E³ jeweils gleiche oder verschiedene Reste, ausgewählt unter Wasserstoff, Alkyl, Cycloalkyl oder Aryl bedeuten,
R_p für Wasserstoff, Methyl oder Ethyl steht,
M⁺ für ein Kationäquivalent steht,
X^– für ein Anionäquivalent steht und
x für eine ganze Zahl von 1 bis 240 steht,
wobei jeweils zwei benachbarte Reste R⁵ und R⁶ und/oder R^5' und R^6' zusammen mit den Kohlenstoffatomen des Pyrrolrings, an die sie gebunden sind, auch für ein kondensiertes Ringsystem mit 1, 2 oder 3 weiteren Ringen stehen können.Preferred are pnicogen compounds in which the substituent R ¹ together with the substituent R ^{2 is} a bispyrrole group of the formula II.a or II.b

forms what
I stands for a chemical bond or for O, S, SiR ^ε R ^ζ , NR ^η or optionally substituted C ₁ -C ₁₀ alkylene, preferably CR ^λ R ^μ , where R ^ε , R ^ζ , R ^η , R ^λ and R ^μ independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
R ⁵ , R ^{5 '} , R ⁶ , R ^6' , R ⁷ , R ^{7 '} , R ⁸ and R ^8' independently of one another for hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, WCOOR ^° , WCOO ^- M ⁺ , W (SO ₃ ) R ^° , W (SO ₃ ) ^- M ⁺ , WPO ₃ (R ^° ) (R ^p ), W (PO ₃ ) ^2– (M ⁺ ) ₂ , WNE ¹ E ² , W (NE ¹ E ² E ³ ) ⁺ X ^- , WOR ^° , WSR ^° , (CHR ^° CH ₂ O) _x R ^° , (CH ₂ NE ¹ ) _x R ^° , (CH ₂ CH ₂ NE ¹ ) _x R ^° , halogen, Perfluoroalkyl, preferably trifluoromethyl, nitro, acyl or cyano, in which
W represents a single bond, a hetero atom, a hetero atom-containing group or a divalent bridging group with 1 to 20 bridge atoms,
R ^° , E ¹ , E ² , E ³ each represent the same or different radicals selected from hydrogen, alkyl, cycloalkyl or aryl,
R _{p represents} hydrogen, methyl or ethyl,
M ^{+ stands} for a cation equivalent,
X ^{- stands} for an anion equivalent and
x represents an integer from 1 to 240,
where two adjacent radicals R ⁵ and R ⁶ and / or R ^{5 '} and R ^6' together with the carbon atoms of the pyrrole ring to which they are attached can also represent a condensed ring system with 1, 2 or 3 further rings.

I is preferably a chemical bond or a C ₁ -C ₄ alkylene group, particularly preferably a methylene group.

To illustrate, some advantageous "bispyrrolyl groups" are listed below:

The radical R ³ is preferably selected from hydrogen, C ₁ -C ₆ -alkyl, tri-C ₁ -C ₄ -alkylsilyl, in particular trimethylsilyl, triarylsilyl, in particular triphenylsilyl, and phenyl. If the radical R ^{3 is} C ₁ -C ₆ alkyl, then in particular methyl, ethyl, isopropyl or tert-butyl.

worin
R^I, R^I', R^II, R^II', R^III, R^III', R^IV, R^IV', R^V, R^VI, R^VII, R^VIII, R^IX R^X, R^XI und R^XII unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl, Hetaryl, Hydroxy, Thiol, Polyalkylenoxid, Polyalkylenimin, Alkoxy, Halogen, SO₃H, Sulfonat, NE⁶E⁷, Alkylen-NE⁶E⁷, Trifluormethyl, Nitro, Alkoxycarbonyl, Carboxyl, Acyl oder Cyano stehen, worin E⁶ und E⁷ jeweils gleiche oder verschiedene Reste, ausgewählt unter Wasserstoff, Alkyl, Cycloalkyl und Aryl bedeuten,
Z für O, S, NR¹⁵ oder SiR¹⁵R¹⁶ steht, wobei R¹⁵ und R¹⁶ unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl oder Hetaryl stehen,
oder Z für eine C₁-C₄-Alkylenbrücke steht, die eine Doppelbindung und/oder einen Alkyl-, Cycloalkyl-, Heterocycloalkyl-, Aryl- oder Hetaryl-Substituenten aufweisen kann,
oder Z für eine C₂-C₄-Alkylenbrücke steht, die durch 0, S oder NR¹⁵ oder SiR¹⁵R¹⁶ unterbrochen ist,
wobei in den Gruppen der Formel III.a zwei benachbarte Reste R⁺ bis R^VI gemeinsam mit den Kohlenstoffatomen des Benzolkerns, an die sie gebunden sind, auch für ein kondensiertes Ringsystem mit 1, 2 oder 3 weiteren Ringen stehen können,
wobei in den Gruppen der Formeln III.g bis III.m zwei geminale Reste R^I, R^I'; R^II, R^II'; R^III, R^III' und/oder R^IV, R^IV' auch für Oxo oder ein Ketal davon stehen kann,
A¹ und A² unabhängig voneinander für O, S, SiR^aR^b, NR^c oder CR^dR^e stehen, wobei
R^a, R^b und R^c unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl oder Hetaryl stehen,
R^d und R^e unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Heterocycloalkyl, Aryl oder Hetaryl stehen oder R^d und R^e gemeinsam für Oxo oder ein Ketal davon stehen oder die Gruppe R^d gemeinsam mit einer weiteren Gruppe R^d oder die Gruppe R^e gemeinsam mit einer weiteren Gruppe R^e eine intramolekulare Brückengruppe D bilden,
D eine zweibindige Brückengruppe, vorzugsweise ausgewählt aus den Gruppen

ist, in denen
R⁹, R^9', R¹⁰ und R^10' unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Aryl, Halogen, Trifluormethyl, Carboxyl, Carboxylat oder Cyano stehen oder miteinander zu einem 3- bis 6-gliedrigen nichtaromatischen Carbocyclus verbunden sind,
R¹¹, R¹², R¹³ und R¹⁴ unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Aryl, Halogen, Trifluormethyl, COOH, Carboxylat, Cyano, Alkoxy, SO₃H, Sulfonat, NE⁶E⁷, Alkylen-NE⁶E⁷E⁸⁺X^–, Acyl oder Nitro stehen,
c 0 oder 1 ist.According to a preferred embodiment, the bridging group Y is selected from groups of the formulas III.a to III.t.

wherein
R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV , R ^IV' , R ^V , R ^VI , R ^VII , R ^VIII , R ^IX R ^X , R ^XI and R ^XII independently of one another for hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, hydroxy, thiol, polyalkylene oxide, polyalkyleneimine, alkoxy, halogen, SO ₃ H, sulfonate, NE ⁶ E ⁷ , alkylene-NE ⁶ E ⁷ , trifluoromethyl, nitro, alkoxycarbonyl , Carboxyl, acyl or cyano, in which E ⁶ and E ⁷ each denote the same or different radicals selected from hydrogen, alkyl, cycloalkyl and aryl,
Z represents O, S, NR ¹⁵ or SiR ¹⁵ R ¹⁶ , where R ¹⁵ and R ¹⁶ independently represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
or Z represents a C ₁ -C ₄ alkylene bridge which can have a double bond and / or an alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl substituent,
or Z represents a C ₂ -C ₄ alkylene bridge which is interrupted by 0, S or NR ¹⁵ or SiR ¹⁵ R ¹⁶ ,
where in the groups of the formula III.a two adjacent radicals R ⁺ to R ^VI together with the carbon atoms of the benzene nucleus to which they are attached can also represent a condensed ring system with 1, 2 or 3 further rings,
where in the groups of the formulas III.g to III.m two geminal radicals R ^I , R ^{I '} ; R ^II , R ^{II '} ; R ^III , R ^{III '} and / or R ^IV , R ^{IV' can} also represent oxo or a ketal thereof,
A ¹ and A ² independently of one another represent O, S, SiR ^a R ^b , NR ^c or CR ^d R ^e , where
R ^a , R ^b and R ^c independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
R ^d and R ^e independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl or R ^d and R ^e together represent oxo or a ketal thereof or the group R ^d together with a further group R ^d or the group R ^e together with another group R ^{e form} an intramolecular bridge group D,
D is a double-bonded bridge group, preferably selected from the groups

is where
R ⁹ , R ^{9 '} , R ¹⁰ and R ^10' independently of one another represent hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, carboxyl, carboxylate or cyano or are connected to one another to form a 3- to 6-membered non-aromatic carbocycle,
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ independently of one another for hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, COOH, carboxylate, cyano, alkoxy, SO ₃ H, sulfonate, NE ⁶ E ⁷ , alkylene-NE ⁶ E ⁷ E ⁸⁺ X ^- , acyl or nitro,
c is 0 or 1.

In the event that c = 0, the groups A ¹ and A ^{2 are} not linked to one another by a single bond connected.

The bridge group Y is preferably a group of the formula III.a. In group III.a, groups A ¹ and A ^{2 can} generally be independently of one another for O, S (only for c = 0), SiR ^a R ^b ,
NR ^c or CR ^d R ^e (for c = 0 or 1), where the substituents R ^a , R ^b and R ^{c can} in general independently of one another be hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, whereas the Groups Rd and Re independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl or Rd and Re together represent oxo or a ketal thereof or the group Rd together with another group Rd or the group Re together with another group Re can form an intramolecular bridge group D.

in denen R⁹, R^9', R¹⁰ und R^10' unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Aryl, Halogen, Trifluormethyl, Carboxyl, Carboxylat oder Cyano stehen oder miteinander zu einem 3- oder 6-gliedrigen nichtaromatischen Carbocyclus verbunden sind und R¹¹, R¹², R¹³ und R¹⁴ unabhängig voneinander für Wasserstoff, Alkyl, Cycloalkyl, Aryl, Halogen, Trifluormethyl, COOH, Carboxylat, Cyano, Alkoxy, SO₃H, Sulfonat, NE¹E², Alkylen-NE¹E²E³⁺X^–, Aryl oder Nitro stehen können. Vorzugsweise stehen die Gruppen R⁹, R^9', R¹⁰ und R^10' für Wasserstoff, C₁-C₁₀-Alkyl oder Carboxylat und die Gruppen R¹¹, R¹², R¹³ und R¹⁴ für Wasserstoff, C₁-C₁₀-Alkyl, Halogen, insbesondere Fluor, Chlor oder Brom, Trifluormethyl, C₁-C₄-Alkoxy, Carboxylat, Sulfonat oder C₁-C₈-Aryl. Besonders bevorzugt stehen R⁹, R^9', R¹⁰, R^10', R¹¹, R¹², R¹³ und R¹⁴ für Wasserstoff. Für den Einsatz in einem wässrigen Reaktionsmedium sind solche Pnicogenchelatverbindungen bevorzugt, in denen 1, 2 oder 3, vorzugsweise 1 oder 2, insbesondere 1 der Gruppen R¹¹, R¹², R¹³, und/oder R¹⁴ für eine COO^–M⁺, eine SO₃ ^–M⁺ oder eine (NE¹E²E³)⁺X^–-Gruppe stehen, wobei M⁺ und X^– die vorstehend genannte Bedeutung haben.D is a double-bonded bridging group, which is preferably selected from the groups

in which R ⁹ , R ^{9 '} , R ¹⁰ and R ^10' independently of one another represent hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, carboxyl, carboxylate or cyano or are connected to one another to form a 3- or 6-membered non-aromatic carbocycle and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ independently of one another for hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, COOH, carboxylate, cyano, alkoxy, SO ₃ H, sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² E ³⁺ X ^- , aryl or nitro. The groups R ⁹ , R ^{9 '} , R ¹⁰ and R ^10' are preferably hydrogen, C ₁ -C ₁₀ alkyl or carboxylate and the groups R ¹¹ , R ¹² , R ¹³ and R ^{14 are} hydrogen, C ₁ -C ₁₀ alkyl, halogen, in particular fluorine, chlorine or bromine, trifluoromethyl, C ₁ -C ₄ alkoxy, carboxylate, sulfonate or C ₁ -C ₈ aryl. R ⁹ , R ^{9 '} , R ¹⁰ , R ^10' , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are particularly preferably hydrogen. For use in an aqueous reaction medium, pnicogen chelate compounds are preferred in which 1, 2 or 3, preferably 1 or 2, in particular 1 of the groups R ¹¹ , R ¹² , R ¹³ and / or R ¹⁴ for a COO ^- M ⁺ , are a SO ₃ ^- M ⁺ or a (NE ¹ E ² E ³ ) ⁺ X ^- group, where M ⁺ and X ^{- have} the meaning given above.

die 1,2-Phenylengruppe

die Norbornan-2,3-diylgruppe

und die Cyclopentan-1,2-diylgruppe

Particularly preferred bridge groups D are the ethylene group

the 1,2-phenylene group

the norbornane-2,3-diyl group

and the cyclopentane-1,2-diyl group

If R ^d forms an intramolecular bridging group D with another group R ^d or R ^e with another group R ^e , ie the index c in this case is 1, it is inevitable that both A ¹ and A ² together form one bridging group, preferably a CR ^d R ^e group, and are the bridging group Y of the formula III.a preferably in this case, a triptycene like or ethanoanthracene-like carbon skeleton has.

Preferred linking groups Y of formula III.a are other than those with a triptycene-like carbon skeleton, those in which the subscript c is 0, and selected the groups A ¹ and A ² are selected from the groups O, S, and CR ^d R ^e, in particular O, S, the methylene group (R ^d = R ^e = H), the dimethylmethylene group (R ^d = R ^e = CH ₃ ), the diethylene group (R ^d = R ^c = C ₂ H ₅ ), the di-n-propyl -methylene group (R ^d = R ^e = n-propyl) or the di-n-butylmethylene group (R ^d = R ^e = n-butyl). In particular, those bridging groups Y are preferred in which A ¹ is different from A ² , where A ^{1 is} preferably a CR ^d R ^e group and A ^{2 is} preferably an O or S group, particularly preferably an oxa group O.

Also preferred are bridge groups Y of the formula III.a, in which A ^{1 is} CR ^d R ^e , where R ^d and R ^e together are oxo (A ¹ is C = O). A ^{2 is} then preferably O or S. Preferred bridge groups Y are therefore also those which are composed of a xanthone (A ² : O) or thioxanthone-like (A ² : S) structure.

Linking groups Y of formula III.a Particularly preferred are thus those which like triptycene of a, ethanoanthracene-like or xanthene type (A ^1: CR ^d R ^e, A ^2: O) backbone are constructed.

In the bridging groups Y of the formula III.a, the substituents R ^I , R ^II , R ^III , R ^IV , R ^V , R ^{VI are} preferably selected from hydrogen, alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl and hetaryl. According to a first preferred embodiment, R ^I , R ^II , R ^III , R ^IV , R ^V and R ^{VI are} hydrogen. According to a further preferred embodiment, R ^I and R ^{VI are} independently of one another C ₁ -C ₄ alkyl or C ₁ -C ₄ alkoxy. R ^I and R ^VI are preferably selected from methyl, ethyl, isopropyl, tert-butyl and methoxy. In these compounds, R ^II , R ^III , R ^IV and R ^V are preferably hydrogen. According to a further preferred embodiment, R ^II and R ^V independently of one another are C ₁ -C ₄ alkyl or C ₁ -C ₄ alkoxy. R ^II and R ^V are preferably selected from methyl, ethyl, isopropyl and tert-butyl. R ^I , R ^III , R ^IV and R ^VI in these compounds are preferably hydrogen.

If two adjacent radicals in the bridge groups Y of the formula III.a, selected from R ^I , R ^II , R ^III , R ^IV , R ^V and R ^VI , stand for a fused-on, ie fused, ring system, it is preferably benzene - or naphthalene rings. Fused benzene rings are preferably unsubstituted or have 1, 2 or 3, in particular 1 or 2, substituents which are selected from alkyl, alkoxy, halogen, SO ₃ H, sulfonate, NE ¹ E ² , alkylene-NE ¹ E ² , trifluoromethyl, Nitro, COOR ^f , alkoxycarbonyl, acyl and cyano. Fused naphthalene rings are preferably unsubstituted or have a total of 1, 2 or 3, in particular 1 or 2, of the substituents mentioned above for the fused benzene rings in the non-fused ring and / or in the fused ring.

Y is preferably a group of the formula III.b, in which R ^IV and R ^V independently of one another are C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^IV and R ^V are preferably selected from methyl, ethyl, isopropyl, tert-butyl and methoxy. In these compounds, R ^I , R ^II , R ^III , R ^VI , R ^VII and R ^VIII are preferably hydrogen.

Y is furthermore preferably a group of the formula III.b, in which R ^I and R ^VIII independently of one another are C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I and R ^VIII are particularly preferably tert-butyl. In these compounds, R ^II , R ^III , R ^IV , R ^V , R ^VI , R ^VII are particularly preferably hydrogen. Furthermore, in these compounds R ^III and R ^VI are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^III and R ^VI are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy.

Y is furthermore preferably a group of the formula III.b, in which R ^II and R ^{VII are} hydrogen. In these compounds, R ^I , R ^III , R ^IV , R ^V , R ^VI and R ^VIII are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I , R ^III , R ^IV , R ^V , R ^VI and R ^VIII are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy.

Y is furthermore preferably a group of the formula III.c, in which Z is a C ₁ -C ₄ -alkylene group, in particular methylene. In these compounds, R ^IV and R ^V are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^IV and R ^V are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy. The radicals R ^I , R ^II , R ^III , R ^VI , R ^VII and R ^VIII are preferably hydrogen.

Y is furthermore preferably a group of the formula III.c, in which Z represents a C ₁ -C ₄ -alkylene bridge which has at least one alkyl, cycloalkyl or aryl radical. Z particularly preferably represents a methylene bridge which has two C ₁ -C ₄ -alkyl radicals, in particular two methyl radicals. In these compounds, the radicals R ^I and R ^VIII are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I and R ^VIII are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy.

Y is furthermore preferably a group of the formula III.d, in which R ^I and R ^XII independently of one another are C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. In particular, R ^I and R ^{XII are} independently selected from methyl, ethyl, isopropyl, tert-butyl, methoxy and alkoxycarbonyl, preferably methoxycarbonyl. In these compounds, the radicals R ^II to R ^XI are particularly preferably hydrogen.

Y is furthermore preferably a group of the formula III.e, in which R ^I and R ^XII independently of one another are C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. In particular, R ^I and R ^{XII are} independent of one another selected from methyl, ethyl, isopropyl, tert-butyl and methoxy. In these compounds, the radicals R ^II to R ^XI are particularly preferably hydrogen.

Y is further preferably a group of the formula III.f, where Z is a C ₁ -C ₄ -alkylene group which has at least one alkyl, cycloalkyl or aryl substituent. Z particularly preferably represents a methylene group which has two C ₁ -C ₄ -alkyl radicals, especially two methyl radicals. In these compounds, the radicals R ^I and R ^VIII are particularly preferably, independently of one another, C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. In particular, R ^I and R ^{VIII are} independently selected from methyl, ethyl, isopropyl, tert-butyl and methoxy. The radicals R ^II , R ^III R ^IX , R ^V , R ^VI and R ^VII are preferably hydrogen.

Y is furthermore preferably a group of the formula III.g, where R ^I , R ^{I '} , R ^II , R ^II' , R ^III and R ^{III 'are} hydrogen.

Y is furthermore preferably a group of the formula III.g, in which R ^II and R ^{II '} together represent an oxo group or a ketal thereof and the other radicals represent hydrogen.

Y is furthermore preferably a group of the formula III.h, in which R ^I , R ^{I '} , R ^II , R ^II' , R ^III and R ^{III 'are} hydrogen.

Y is furthermore preferably a group of the formula III.h, in which R ^II and R ^{II '} together represent an oxo group or a ketal thereof and the other radicals represent hydrogen.

Y is furthermore preferably a group of the formula III.i in which R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV and R ^{IV' are} hydrogen.

Furthermore, Y preferably represents a group of the formula III.k, in which R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV and R ^{IV' are} hydrogen.

Y is further preferably a group of the formula III.1, where R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV and R ^{IV' are} hydrogen.

Y is furthermore preferably a group of the formula III.m, in which R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV and R ^{IV' are} hydrogen.

Y is furthermore preferably a group of the formula III.n, in which one of the radicals R ^I to R ^{IV is} C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. At least one of the radicals R ^I to R ^IV is then particularly preferably methyl, ethyl, isopropyl, tert-butyl or methoxy.

Y is furthermore preferably a group of the formula III.o in which one of the radicals R ^I , R ^II , R ^III or R ^{IV is} H, C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. One of the radicals R ^I to R ^IV is then particularly preferably methyl, ethyl, tert-butyl or methoxy.

Y is furthermore preferably a group of the formula III.p, in which R ^I and R ^VI independently of one another are H, C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I and R ^VI are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy. In these compounds, R ^II , R ^III , R ^IV and R ^V are particularly preferably hydrogen. Furthermore, in the compounds III.p R ^I , R ^III , R ^IV and R ^VI are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I , R ^III , R ^IV and R ^{VI are} then particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy.

Y is furthermore preferably a group of the formula III.q, where R ^I and R ^VI independently of one another are C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^I and R ^VI are particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy. In these compounds, R ^II , R ^III , R ^IV and R ^V are particularly preferably hydrogen. Furthermore, in these compounds R ^III and R ^IV are preferably independently of one another C ₁ -C ₄ -alkyl or C ₁ -C ₄ -alkoxy. R ^III and R ^{IV are} then particularly preferably selected independently of one another from methyl, ethyl, isopropyl, tert-butyl and methoxy.

Furthermore, Y preferably represents a group of the formula III.r, III.s or III.t, in which Z represents CH ₂ , C ₂ H ₂ or C ₂ H ₄ .

In the compounds of formulas III.r, III.s and III.t are alike for the shown bonds to the bridged groups endo and exo position possible.

Me = Methyl
Et = Ethyl
R^g = H, Carbonsäuremethylester
R^h = H, CarbonsäuremethylesterA few advantageous compounds are listed below only to illustrate the pnicogen compounds according to the invention:

Me = methyl
Et = ethyl
R ^g = H, carboxylic acid methyl ester
R ^h = H, carboxylic acid methyl ester

The preparation of the pnicogen compounds according to the invention can expediently start from compounds of the general formula IV L- (O) _a -YOR ³ (IV) take place in which Y, R ³ and a have the abovementioned meaning and L represents a leaving group. In this case, for the preparation of the ligand with an electrophilic pnicogen compound z. B. HalPnR ¹ R ² implemented. Suitable leaving groups L, if a is the number 0, are, for example, alkali metals or alkaline earth metal halides, such as, for. B. Li or MgBr. Suitable leaving groups L, if a stands for the number 1, are, for example, hydrogen and salts, for. B. the Li, Na, K ammonium salts. In this case, for the preparation of the ligand with an electrophilic pnicogen compound z. B. HalPnR ¹ R ² implemented.

To link the PnR ¹ R ^{2 groups} , the compounds of the general formula IV are advantageously reacted with a halogen compound of the formula HalPnR ¹ R ² in the presence of a base. Hal is preferably chlorine or bromine.

Compounds HalPnR ¹ R ² , in which R ¹ and R ^{2 represent} pyrrole groups as defined above, can be used, for example, in analogy to the method of Petersen et al., J. Am. Chem. Soc. 117, 7696 (1995) by reacting the pyrrole compound in question, e.g. B. pyrrole, indole, benzotriazole, carbazole, 2,2'-dipyrrolmethane, 2,2'-bisindole, with the pnicogen trihalide in question, e.g. B. phosphorus trichloride, in the presence of a tertiary amine, e.g. B. triethylamine, are obtained, the stoichiometry of this reaction being observed.

The preparation of pnicogen compounds according to the invention, in which Y represents a bridge group of the xanthene type, can be carried out, for example, according to the following scheme:

The preparation of the starting compounds with triptycene-like carbon skeleton can in a known manner from the corresponding anthraquinone derivatives via the corresponding anthracene precursors (For production see e.g. J. Org. Chem. 45, 1807 (1980); J. Org. Chem. 38, 1167 (1973); Bull Chem. Soc. Jm. 44, 1649 (1971); J. Am. Chem. Soc. 34: 3089 (1969); J. Org. Chem. 39, 770 (1974); Chem. Ber. 124, 333 (1991); J. Org. Chem. 51, 921 (1986)) by their Diels-Alder reaction with the corresponding olefins, acetylenes or Arines are done. Information on the implementation of these Diels-Alder reactions can be found in Chem. Ber. 119: 1016 (1986) and J.C.S. Chem. Comm. 961 (1999).

Another object of the invention is a catalyst comprising at least one complex of a metal VIII. Subgroup with at least one compound according to the invention of formula I as previously defined.

The catalysts according to the invention and used according to the invention can have one or more of the compounds of the general formula I as ligands. In addition to the ligands of the general formula I described above, you can also at least one further ligand, which is selected from halides, amines, carboxylates, acetylacetonate, aryl or alkyl sulfonates, hydride, CO, olefins, dienes, cycloolefins, nitriles, N-containing Heterocycles, aromatics and heteroaromatics, ethers, PF ₃ , phospholes, phosphabenzenes and monodentate, bidentate and multidentate phosphine, phosphinite, phosphonite, phosphoramidite and phosphite ligands. Combinations with those in the are preferred PCT / EP02 / 03543 described ligands.

It is preferably the Metal of subgroup VIII around cobalt, ruthenium, rhodium, palladium, Platinum, osmium or iridium and in particular cobalt, nickel, Rhodium, ruthenium and iridium.

In general, under hydroformylation conditions, catalytically active species of the general formula H _x M _y (CO) _z L _{q are} formed from the catalysts or catalyst precursors used in each case, in which M is a metal of subgroup VIII, L is a phosphorus-containing compound of the formula I and q , x, y, z are integers, depending on the valency and type of the metal and the binding nature of the ligand L. Preferably, z and q are independently at least 1, such as. B. 1, 2 or 3. The sum of z and q is preferably from 1 to 5. The complexes can, if desired, additionally have at least one of the further ligands described above.

According to a preferred embodiment the hydroformylation catalysts are used in situ for the hydroformylation reaction reactor used. If desired, the catalysts of the invention however, also produced separately and isolated by customary methods become. For in situ production of the catalysts according to the invention can you e.g. B.

at least one general connection Formula I, a compound or a complex of a metal of VIII. Subgroup, possibly at least one additional one Ligands and optionally an activating agent in an inert solvent implement under the hydroformylation conditions.

Suitable rhodium compounds or complexes are e.g. B. rhodium (II) and rhodium (III) salts, such as rhodium (III) chloride, Rhodium (III) nitrate, rhodium (III) sulfate, potassium rhodium sulfate, Rhodium (II) or rhodium (III) carboxylate, rhodium (II) and rhodium (III) acetate, Rhodium (III) oxide, salts of rhodium (III) acid, trisammonium hexachlororhodate (III) etc. Also suitable are rhodium complexes, such as rhodium biscarbonylacetylacetonate, Acetylacetonatobisethylene rhodium (I) etc. Rhodium biscarbonylacetylacetonate are preferred or rhodium acetate used.

Ruthenium salts or compounds are also suitable. Suitable ruthenium salts are, for example, ruthenium (III) chloride, ruthenium (IV), ruthenium (VI) or ruthenium (VIII) oxide, alkali metal salts of ruthenium oxygen acids such as K ₂ RuO ₄ or KRuO ₄ or complex compounds, such as, for. B. RuHCl (CO) (PPh ₃ ) ₃ . The metal carbonyls of ruthenium such as trisruthenium dodecacarbonyl or He xaruthenium octadecacarbonyl, or mixed forms in which CO is partially replaced by ligands of the formula PR ₃ , such as Ru (CO) ₃ (PPh ₃ ) ₂ , are used in the process according to the invention.

Suitable cobalt compounds are for example cobalt (II) chloride, cobalt (II) sulfate, cobalt (II) carbonate, Cobalt (II) nitrate, its amine or hydrate complexes, cobalt carboxylates, such as cobalt acetate, cobalt ethyl hexanoate, cobalt naphthanoate, and the cobalt-caproat complex. The carbonyl complexes of cobalt can also be found here such as dicobalt octacarbonyl, tetracobalt dodecacarbonyl and hexacobalt hexadecacarbonyl be used.

The above and other suitable ones Compounds of cobalt, rhodium, ruthenium and iridium are known in principle and adequately described in the literature or they can prepared by a person skilled in the art in analogy to the already known compounds become.

Suitable activating agents are e.g. B. Brönsted acids, Lewis acids, such as. B. BF ₃ , AlCl ₃ , ZnCl ₂ , and Lewis bases.

The solvents used are preferably the aldehydes which are formed in the hydroformylation of the respective olefins, and their higher-boiling secondary reaction products, for. B. the products of aldol condensation. Likewise suitable solvents are aromatics, such as toluene and xylenes, hydrocarbons or mixtures of hydrocarbons, also for diluting the above-mentioned aldehydes and the secondary products of the aldehydes. Other solvents are esters of aliphatic carboxylic acids with alkanols, for example ethyl acetate or Texanol ^™ , ethers such as tert-butyl methyl ether and tetrahydrofuran. If the ligands are sufficiently hydrophilized, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ketones such as acetone and methyl ethyl ketone etc. can also be used. So-called "ionic liquids" can also be used as solvents. These are liquid salts, for example N, N'-dialkylimidazolium salts such as the N-butyl-N'-methylimidazolium salts, tetraalkylammonium salts such as the tetra-n-butylammonium salts, N-alkylpyridinium salts such as the n-butylpyridinium salts, tetradecyl) phosphonium salts, e.g. B. the tetrafluoroborates, acetates, tetrachloroaluminates, hexafluorophosphates, chlorides and tosylates.

Furthermore, it is also possible to implement the reactions in water or aqueous solvent systems which, in addition to water, contain a water-miscible solvent, for example an alcohol such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, a ketone such as acetone and methyl ethyl ketone contain another solvent. For this purpose, ligands of the formula I are used which are modified with polar groups, for example ionic groups such as SO ₃ M, CO ₂ M with M = Na, K or NH ₄ or like N (CH ₃ ) ₄ ⁺ . The reactions then take the form of two-phase catalysis, the catalyst being in the aqueous phase and feedstocks and products forming the organic phase. The implementation in the "Ionic Liquids" can also be designed as a two-phase catalysis.

The molar ratio of phosphorus Ligand to metal of subgroup VIII generally lies in one Range from about 1: 1 to 1000: 1.

As substrates for the hydroformylation process according to the invention In principle, all connections come into consideration, which one or several ethylenically unsaturated Double bonds included. These include e.g. B. olefins, such as α-olefins, internal straight chain and internal branched olefins. Suitable α-olefins are z. B. ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-non, 1-decene, 1-undecene, 1-dodecene etc.

Suitable branched, internal olefins are preferably C ₄ -C ₂₀ olefins, such as 2-methyl-2-butene, 2-methyl-2-pentene, 3-methyl-2-pentene, branched, internal heptene mixtures, branched, in ternary octene mixtures, branched, internal non-mixtures, branched, internal decene mixtures, branched, internal undecene mixtures, branched, internal dodecene mixtures etc.

Suitable olefins to be hydroformylated are furthermore C ₅ -C ₈ cycloalkenes, such as cyclopentene, cyclohexene, cycloheptene, cyclooctene and their derivatives, such as, for. B. their C ₁ -C ₂₀ alkyl derivatives with 1 to 5 alkyl substituents. Suitable olefins to be hydroformylated are furthermore vinyl aromatics, such as styrene, α-methylstyrene, 4-isobutylstyrene etc. Suitable olefins to be hydroformylated are furthermore α, β-ethylenically unsaturated mono- and / or dicarboxylic acids, their esters, half-esters and amides, such as acrylic acid, methacrylic acid acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, methyl 3-pentenoate, methyl 4-pentenoate, methyl oleate, methyl acrylate, methyl methacrylate, unsaturated nitriles such as 3-pentenenitrile, 4-pentenenitrile, acrylonitrile, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl, etc., C ₁ -C ₂₀ alkenols, alkene diols and alkadienols, such as 2,7-octadienol-1. Suitable substrates are further di- or polyenes with isolated or conjugated double bonds. These include e.g. B. 1,3-butadiene, 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene, vinylcyclohexene, dicyclopentadiene, 1,5,9-cyclooctatriene and butadiene homo- and copolymers.

The unsaturated compound used for the hydroformylation is preferably selected from internal linear olefins and olefin mixtures which contain at least one internal linear olefin. Suitable linear (straight-chain) internal olefins are preferably C ₄ -C ₂₀ olefins, such as 2-butene, 2-pentene, 2-hexene, 3-hexene, 2-heptene, 3-heptene, 2-octene, 3-octene, 4-octene etc. and mixtures thereof.

Is preferred in the hydroformylation process according to the invention an industrial scale vehicle accessible Olefin mixture used, in particular at least one internal contains linear olefin.

• – thermisches Cracken (Steamcracken),
• – katalytisches Dehydrieren und
• – chemisches Dehydrieren durch Chlorieren und Dehydrochlorieren.

These include e.g. B. the Ziegler olefins obtained by targeted ethene oligomerization in the presence of alkyl aluminum catalysts. These are essentially unbranched olefins with a terminal double bond and an even number of carbon atoms. These also include the olefins obtained by ethene oligomerization in the presence of various catalyst systems, e.g. B. the predominantly linear α-olefins obtained in the presence of alkyl aluminum chloride / titanium tetrachloride catalysts and the α-olefins obtained in the presence of nickel-phosphine complex catalysts according to the Shell Higher Olefin Process (SHOP). Ge suitable technically accessible olefin mixtures are still in the paraffin dehydrogenation of corresponding petroleum fractions, for. B. the so-called petroleum or diesel oil fractions obtained. Essentially three processes are used to convert paraffins, primarily n-paraffins to olefins:

• - thermal cracking (steam cracking),
• - catalytic dehydration and
• - chemical dehydration by chlorination and dehydrochlorination.

Thereby thermal cracking predominantly leads to α-olefins, while the other variants give olefin mixtures that generally also larger proportions on olefins with internal Have double bond. Suitable olefin mixtures are also the olefins obtained in metathesis or telomerization reactions. These include z. B. the olefins from the Phillips triolefin process, a modified SHOP process from ethylene oligomerization, double bond isomerization and followed by Metathesis (ethenolysis).

Suitable technical olefin mixtures which can be used in the hydroformylation process according to the invention are also selected from dibutenes, tributenes, tetrabutenes, dipropenes, tripropenes, tetrapropenes, mixtures of butene isomers, in particular raffinate II, dihexenes, dimers and oligomers from the Dimersol ^® process from IFP, Octolprocess ^® from Hüls , Polygas process etc.

A method is preferred which characterized in that the hydroformylation catalyst in is produced in situ, wherein at least one compound of Formula I, a compound or a complex of a metal of VIII. Subgroup and optionally an activating agent in an inert solvent brings to reaction under the hydroformylation conditions.

The hydroformylation reaction can continuously, semi-continuously or discontinuously.

Suitable reactors for continuous Implementation are known to the expert and are, for. B. in Ullmanns encyclopedia der Technische Chemie, Vol. 1, 3rd edition, 1951, p. 743 ff.

Suitable pressure-resistant reactors are also known to the skilled person and z. B. in Ullmann's encyclopedia of technical chemistry, vol. 1, 3rd edition, 1951, pp. 769 ff. Generally, for the inventive method an autoclave is used, if desired with a stirrer and can be provided with an inner lining.

The composition of the in the inventive method Synthetic gas used from carbon monoxide and hydrogen can vary widely. The molar ratio of carbon monoxide to Is hydrogen usually around 5:95 to 70:30.

The temperature in the hydroformylation reaction is generally in a range of about 20 to 180 ° C, preferred about 50 to 150 ° C. Generally the pressure is in the range of about 1 to 700 bar, preferably 1 to 600 bar, in particular 1 to 300 bar. The reaction pressure can be dependent from the activity of the hydroformylation catalyst used according to the invention can be varied. In general, the catalysts of the invention allow based on phosphorus-containing compounds Low pressure range, such as in the range of 1 to 100 bar.

The hydroformylation catalysts used according to the invention and the hydroformylation catalysts according to the invention can be classified according to the usual processes known to those skilled in the art of discharging the hydroformylation reaction sever and can generally again for the hydroformylation can be used.

The catalysts described above can also in a suitable manner, e.g. B. by connection via suitable as anchor groups functional groups, adsorption, grafting, etc. to a suitable Carrier, z. B. made of glass, silica gel, synthetic resins, polymers etc., immobilized become. They are then also suitable for use as solid-phase catalysts.

Catalysts based on ligands of the formula I surprisingly show good yields of α-aldehydes or alcohols and in particular also of n-aldehydes or alcohols in the hydroformylation of internal linear olefins (isomerizing hydroformylation). Furthermore, these catalysts generally have a high stability under the hydroformylation conditions, so that they generally achieve a longer catalyst service life than with catalysts based on conventional chelate ligands known from the prior art. This applies in particular to ligands of the formula I in which R ¹ and / or R ^{2 represents} substituted or integrated pyrrole groups in a fused ring system which are covalently linked to the pnicogen atom via their pyrrolic nitrogen atom. The 3-methylindolyl group (skatolyl group) is particularly advantageous. Advantageously, the catalysts according to the invention and used according to the invention continue to have a high activity, so that the corresponding aldehydes are generally obtained in good yields. In the hydroformylation of α-olefins and of internal, linear olefins, they also show a very low selectivity for the hydrogenation product of the olefin used.

• a) Buten oder ein Buten enthaltendes C₄-Kohlenwasserstoffgemisch in Gegenwart eines Katalysators, wie zuvor definiert, mit Kohlenmonoxid und Wasserstoff unter Erhalt eines n-Valeraldehyd enthaltenden Hydroformylierungsprodukts hydroformyliert,
• b) gegebenenfalls das Hydroformylierungsprodukt einer Auftrennung unter Erhalt einer an n-Valeraldehyd angereicherten Fraktion unterzieht,
• c) das in Schritt a) erhaltene Hydroformylierungsprodukt oder die in Schritt b) erhaltene an n-Valeraldehyd angereicherte Fraktion einer Aldolkondensation unterzieht,
• d) die Produkte der Aldolkondensation mit Wasserstoff katalytisch zu Alkoholen hydriert, und
• e) gegebenenfalls die Hydrierprodukte einer Auftrennung unter Erhalt einer an 2-Propylheptanol angereicherten Fraktion unterzieht.

Another object of the invention is a process for the preparation of 2-propylheptanol, in which

• a) butene or a butene-containing C ₄ -hydrocarbon mixture in the presence of a catalyst, as previously defined, hydroformylated with carbon monoxide and hydrogen to give a hydroformylation product containing n-valeraldehyde,
• b) optionally subjecting the hydroformylation product to separation to obtain a fraction enriched in n-valeraldehyde,
• c) subjecting the hydroformylation product obtained in step a) or the fraction enriched in n-valeraldehyde obtained in step b) to an aldol condensation,
• d) the products of the aldol condensation are hydrogenated catalytically to give alcohols, and
• e) optionally subjecting the hydrogenation products to separation to obtain a fraction enriched in 2-propylheptanol.

a) Hydroformylation

Suitable starting materials for the hydroformylation are both essentially pure 1-butene and mixtures of 1-butene with 2-butene and technically available C ₄ hydrocarbon streams which contain 1-butene and / or 2 butene. C ₄ cuts, which are available in large quantities from FCC plants and from steam crackers, are preferably suitable. These consist essentially of a mixture of the isomeric butenes and butane.

Suitable feedstock C ₄ hydrocarbon streams include e.g. B. 50 to 99, preferably 60 to 90 mol% of butenes and 1 to 50, preferably 10 to 40 mol% of butanes. The butene fraction preferably comprises 30 to 60 mol% of 1-butene, 20 to 30 mol% of 2-butene and less than 5 mol%, in particular less than 3 mol%, of isobutene (based on the butene fraction). The so-called raffinate II, which is an isobutene-depleted C _{4 cut} after butadiene separation from an FCC system or a steam cracker, is used as a particularly preferred feedstock.

Hydroformylation catalysts Basis of the used according to the invention Phosphorus chelate compounds as ligands advantageously have high n selectivity, also when using 2-butene and hydrocarbon mixtures containing 2-butene as input material. So you can in the method according to the invention such feedstocks can also be used economically since the desired n-valeraldehyde results in good yields.

b) separation

According to a suitable process variant the one obtained in step a) after separation of the catalyst system product-enriched fraction of a further separation for preservation one enriched in n-valeraldehyde Fraction subjected. The separation of the hydroformylation product into an n-valeraldehyde-enriched fraction and an n-valeraldehyde depleted fraction is carried out according to the usual, known to the expert Method. Distillation using known ones is preferred Separators, such as distillation columns, e.g. B. tray columns, the desired ones with bells, sieve plates, sieve plates, Valves etc. equipped could be, Evaporators, such as thin film evaporators, Falling film evaporator, wiper blade evaporator etc.

c) aldol condensation

Two molecules of C ₅ aldehyde can be condensed to form α, β-unsaturated C ₁₀ aldehydes. The aldol condensation takes place in a manner known per se, for. B. by the action of an aqueous base such as sodium hydroxide solution or potassium hydroxide solution. Alternatively, a heterogeneous basic catalyst, such as magnesium and / or aluminum oxide, can also be used (cf. e.g. the EP-A 792 862 ). The condensation of two molecules of n-valeraldehyde results in 2-propyl-2-heptenal. If the hydroformylation product obtained in step a) or after the separation in step b) has further C ₅ aldehydes, such as 2-methylbutanal and optionally 2,2-dimethylpropanal, these also undergo aldol condensation, the condensation products of all possible then Aldehyde combinations result, for example 2-propyl-4-me thyl-2-hexenal. A portion of these condensation products, e.g. B. of up to 30 wt .-%, an advantageous further processing to 2-propylheptanol-containing C ₁₀ alcohol mixtures suitable as plasticizer alcohols does not conflict.

d) hydrogenation

The products of the aldol condensation can be catalytically hydrogenated with hydrogen to C ₁₀ alcohols, such as in particular 2-propylheptanol.

For the hydrogenation of the C ₁₀ aldehydes to the C ₁₀ alcohols, the catalysts of the hydroformylation are in principle also generally suitable at higher temperatures; however, more selective hydrogenation catalysts are generally preferred, which are used in a separate hydrogenation stage. Suitable hydrogenation catalysts are generally transition metals, such as. B. Cr, Mo, W, Fe, Rh, Co, Ni, Pd, Pt, Ru etc. or mixtures thereof, which increase the activity and stability on supports such. B. activated carbon, aluminum oxide, diatomaceous earth, etc. can be applied. To increase the catalytic activity, Fe, Co and preferably Ni, also in the form of the Raney catalysts, can be used as a metal sponge with a very large surface area. The C ₁₀ aldehydes are hydrogenated as a function of the activity of the catalyst, preferably at elevated temperatures and elevated pressure. The hydrogenation temperature is preferably about 80 to 250 ° C., and the pressure is preferably about 50 to 350 bar.

The crude hydrogenation product can by conventional methods, e.g. B. by distillation to the C ₁₀ alcohols.

e) separation

If desired, the Hydrogenation products of a further separation to obtain one 2-Propylheptanol enriched fraction and a 2-Propylheptanol depleted fraction. This separation can according to usual, the person skilled in the art such. B. by distillation.

Hydroformylation catalysts which have a complex of at least one metal from transition group VIII of the Periodic Table and which have at least one monopnicogen compound of the general formula I as ligands are advantageously suitable for use in a process for the preparation of 2-propylheptanol. The catalysts have a high n-selectivity, so that both when using essentially pure 1-butene and when using 1-butene / 2-butene-containing hydrocarbon mixtures, such as C ₄ cuts, a good yield of n -Valeraldehyde is obtained. Furthermore, the catalysts used according to the invention are also suitable for double bond isomerization from an internal position to a terminal position, so that n-valeraldehyde is obtained in good yields even when using 2-butene and higher concentrations of 2-butene-containing hydrocarbon mixtures. Advantageously, the catalysts used according to the invention based on monopnicogen compound show essentially no decomposition under the hydroformylation conditions, ie in the presence of aldehydes. Advantageously, substantially no decomposition products are formed even in the presence of atmospheric oxygen and / or light and / or acids and / or at room temperature and elevated temperatures, such as up to about 150 ° C., so that complex measures are taken to stabilize the hydroformylation catalyst used , especially in the processing, can be dispensed with.

Another object of the invention is the use of catalysts comprising at least one Complex of a metal of subgroup VIII with at least one Compound of general formula I, as described above, for Hydroformylation, hydrocyanation, carbonylation and for hydrogenation.

The invention is based on the following, not restrictive Examples closer explained.

Example 1:

In a 1 liter four-necked flask equipped with a KPG stirrer, thermometer and dropping funnel, 19.05 g of 3-methylindole (Skatol) were dissolved in 700 ml of absolute toluene under argon and cooled to -75 ° C. 100 ml of absolute triethylethylamine were added and then 6.7 ml of phosphorus trichloride in 100 ml of absolute toluene were added dropwise to the reaction mixture at -75 ° C. After the addition was complete, the cooling bath was removed, the reaction mixture was slowly brought to room temperature and then stirred at 90 ° C. for 12 h. The colorless precipitate was separated off under a protective gas over a frit and washed with a little absolute toluene. The mother liquor was then concentrated to 100 ml in vacuo at 80 ° C. (Reaction control solution A: ³¹ P-NMR (toluene: δ = 103)).

In a 1 liter four-necked flask with KPG stirrer, thermometer and dropping funnels were 23.52 g of 4,5-dihydroxy-2,7-di-tert-butyl-9,9-dimethylxanthene dissolved in 500 ml of absolute tetrahydrofuran under argon at 50 ° C, then cooled to -20 ° C. To this solution were within 30 min. 22 ml of a 15% n-butyllithium solution (hexane) dilute with 50 ml abs. Toluene added dropwise. Then the reaction mixture 3 h at 50 ° C touched.

The toluene solution A was added to this solution by means of a dropping funnel within 30 min. added dropwise at room temperature and, after the addition was complete, stirred at 50 ° C. for 4 h. The resulting colorless solid was filtered off using a protective gas frit and the mother liquor was then evaporated to dryness in vacuo at 80 ° C. This was followed by extraction with dichloromethane and chromatographic separation on silica gel with dichloromethane as the mobile phase. 11.5 g of a colorless solid were obtained.
¹ H-NMR (C ₆ D ₆ , 360.1 MHz, 298 K):
δ = 1.07 (s, tBu, 9H), 1.20 (s, tBu, 9H), 1.51 (s, C (CH ₃ ) ₂ , 6H), 2.10 (s, CH ₃ , 6H) ), 5.49 (s, OH, 1H), 6.90 (s, Ar-H, 1H), 6.94 (d, J = 2 Hz, Ar-H, 1H), 6.99 (d, J = 2 Hz, Ar-H, 1H), 7.14-7.18 (m, superimposed by CD ₅ H signal), 7.34 (s, Ar-H, 2H), 7.47-7, 50 (m, Ar-H, 2H), 7.88-7.90 (m, Ar-H, 2H).
³¹ P (C ₆ D ₆ , 145.8 MHz, 298K): δ = 109 (s).

Example 2: Synthesis of Ligand II:

3.6 g of 3-methylindole (Skatol) were placed in a 250 ml 3-necked flask with thermometer and magnetic stirrer. dissolved in 200 ml of absolute (abs.) tetrahydrofuran (THF) under argon and cooled to -75 ° C. 18 ml of abs. Triethylethylamine added and then 1.3 ml of phosphorus trichloride added dropwise at -75 ° C to the reaction mixture. After the addition was complete, the cooling bath was removed, the reaction mixture was slowly brought to room temperature and then stirred at room temperature for 12 h. The colorless precipitate was separated off using a protective gas frit and with a little abs. Washed THF. Then the reaction mixture was concentrated to about 20 ml in vacuo and then with 10 ml abs. Triethylethylamine added. 2.27 g of 2,2'-dihydroxy-3,3 ', 5,5'-tetra-tert-butyl-6,6'-dimethylbiphenol were dissolved in 30 ml of abs. THF was added dropwise between 0 and -20 ° C within 3 h using a dropping funnel. After the addition was complete, the mixture was stirred at room temperature for 2 days. The resulting colorless solid was filtered off using a protective gas frit and the mother liquor was then evaporated to dryness in vacuo at 40 ° C. The residue was slurried in hexane and the insoluble solid was filtered off through a protective gas frit and dried in vacuo. 0.9 g of a colorless solid were obtained.
¹ H-NMR (C ₆ D ₆ , 360.1 MHz, 298K)
δ = 1.04 (s, tBu, 9H), 1.20 (s, tBu, 9H), 1.32 (s, tBu, 9H), 1.63 (s, tBu, 9H), 1.91 ( s, CH ₃ , 3H), 2.11 (s, CH ₃ , 3H), 2.13 (s, CH ₃ , 3H), 2.14 (s, CH ₃ , 3H), 5.16 (s, OH, 1H), 6.95-7.12 (m, Ar-H, 5H), 7.32-7.42 (m, Ar-H, 4H), 7.53 (d, J = 7.9 Hz, Ar-H, 1H), 7.63 (s, Ar-H, 1H), 8.01 (d, J = 7.9 Hz, Ar-H, 1H).
³¹ P (C ₆ D ₆ , 145.8 MHz, 298K): δ = 98 (s).
HMS (ESI) (C ₄₈ H ₆₁ N ₂ O ₂ P + H): m / z = 729.4549 (calculated); m / z = 729.4585 (found)

Hydroformylation of 2-butene with ligand I:

Example 3:

5.2 mg Rh (CO) ₂ acac (acac = acetylacetonate) and 66 mg Ligand I were weighed separately, dissolved in 7.5 g absolute toluene, mixed and mixed at 110 ° C with 10 bar synthesis gas (CO: H ₂ = 1: 1) fumigated. After 30 min. 4.9 g of trans-2-butene were added by means of a pressure lock, and a total pressure of 20 bar was set with synthesis gas (CO: H ₂ = 1: 1) and hydroformylated for 4 h at 110 ° C. (105 ppm Rh, ligand: Rh = 5: 1). After cooling to room temperature, the reactor was depressurized via a cold trap and the reactor discharge and the contents of the cold trap were analyzed by means of gas chromatography. The conversion was 35%, the aldehyde yield was 34% and the n component was 58% (n component = quotient from n-aldehyde to total aldehydes x 100).

Example 4:

5.0 mg Rh (CO) ₂ acac and 68 mg Ligand I were weighed out separately, in 7.5 g abs. Toluene dissolved, mixed and gassed at 110 ° C with 10 bar synthesis gas (CO: H ₂ = 1: 2). After 30 min. 4.7 g of trans-2-butene were added by means of a pressure lock, and a total pressure of 20 bar was set using synthesis gas (CO: H ₂ = 1: 2). The gas supply was then switched to CO: H ₂ = 1: 1 and hydroformylated for 4 h at 110 ° C. (102 ppm Rh, ligand: Rh = 5: 1). After cooling to room temperature, the reactor was depressurized via a cold trap and the reactor discharge and the contents of the cold trap were analyzed by means of gas chromatography. The conversion was 69%, the aldehyde yield 67% and the n content 74%.

Hydroformylation of a Butane / butene mixture with ligand I:

Example 5:

5.2 mg Rh (CO) ₂ acac and 68 mg Ligand I were weighed out separately, in 7.5 g abs. Toluene dissolved, mixed and gassed at 110 ° C with 10 bar synthesis gas (CO: H ₂ = 1: 1). After 30 min. 4.8 g of butene / butane mixture (2-butene 44%, 1-butene 39%, isobutene 3%, butanes 14%) were added by means of a pressure lock, with synthesis gas (CO: H ₂ = 1: 1) Total pressure set at 20 bar and hydroformylated for 4 h at 110 ° C (103 ppm Rh, ligand: Rh = 5: 1). After cooling to room temperature, the reactor was depressurized via a cold trap and the reactor discharge and the contents of the cold trap were analyzed by means of gas chromatography. The conversion of the butenes was 80%, the aldehyde yield 79% and the n content 64%.

Example 6:

5.7 mg Rh (CO) ₂ acac and 70 mg Ligand I were weighed in separately, in 7.5 g abs. Toluene dissolved, mixed and gassed at 110 ° C with 10 bar synthesis gas (CO: H ₂ = 1: 2). After 30 min. 5.3 g of butene / butane mixture (2-butene 44%, 1-butene 39%, isobutene 3%, butanes 14%) were added by means of a pressure lock, and with synthesis gas (CO: H ₂ = 1: 2) a total pressure of 20 bar is set. Then the gas supply was turned on CO: H ₂ = 1: 1 changed over and hydroformylated for 4 h at 110 ° C (111 ppm Rh, ligand: Rh = 5: 1). After cooling to room temperature, the reactor was depressurized via a cold trap and the reactor discharge and the contents of the cold trap were analyzed by means of gas chromatography. The conversion of the butenes was 84%, the aldehyde yield 80% and the n content 81%.

Example 7:

4.8 mg of Rh (CO) ₂ acac, 67 mg of ligand I were weighed separately, added to each 3.5 g of Texanol ^®, and mixed at 110 ° C and 10 bar of synthesis gas (CO 2: H ₂ = 1), gassed , After 30 min. 11.0 g of butene / butane mixture (2-butene 44%, 1-butene 39%, isobutene 3%, butanes 14%) were added by means of a pressure lock, and with synthesis gas (CO: H ₂ = 1: 2) a total pressure of 20 bar is set. The gas supply was then switched to CO: H ₂ = 1: 1 and hydroformylated for 4 h at 110 ° C. (106 ppm Rh, ligand: Rh = 5: 1). After cooling to room temperature, the reactor was depressurized via a cold trap and the reactor discharge and the contents of the cold trap were analyzed by means of gas chromatography. The conversion of the butenes was 74%, the aldehyde yield 66% and the n content 77%.

Claims (12)

Monopnicogen compounds of the general formula I

wherein Pn represents a pnicogen atom selected from the elements phosphorus, arsenic or antimony, R ^{1 represents} a pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom, R ^{2 represents} alkyl, alkoxy, aryl, aryloxy, cycloalkyl, cycloalkoxy, heterocycloalkyl, heterocycloalkoxy , a pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom or a hetaryl group different therefrom, or R ¹ together with R ^{2 forms} a divalent heteroatom-containing group which contains at least one pyrrole group bonded to the pnicogen atom via the pyrrolic nitrogen atom, a the number 0 or 1 means Y represents a divalent bridging group with 2 to 10 bridging atoms between the flanking bonds, and R ^{3 represents} hydrogen, alkyl, aryl, cycloalkyl, heterocycloalkyl, hetaryl or silyl. Compounds according to claim 1, wherein at least one of the radicals R ¹ and R ^{2 is} selected from groups of the formulas Ia to Ik

wherein Alk is a C ₁ -C ₄ alkyl group, R ^{α is} a C ₁ -C ₄ alkyl group or an aryl group, and R ^g , R ^h , R ⁱ and R ^k independently of one another for hydrogen, C ₁ -C ₄ - Alkyl, C ₁ -C ₄ alkoxy, acyl, halogen, trifluoromethyl, C ₁ -C ₄ alkoxycarbonyl or carboxyl. Compounds according to claim 2, wherein at least one of the radicals R ¹ and R ^{2 represents} a 3-alkylindolyl group, preferably a 3-methylindolyl group. Compounds according to claim 1, wherein R ¹ together with R ^{2 is} a group of formula II.a or II.b

forms what I stands for a chemical bond or for O, S, SiR ^ε RS ^ζ NR ^η or optionally substituted C ₁ -C ₁₀ alkylene, preferably CR ^λ R ^μ , where R ^ε , R ^ζ , R ^η , R ^λ and R ^μ independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, R ⁵ , R ^{5 '} , R ⁶ , R ^6' , R ⁷ , R ^{7 '} , R ⁸ and R ^8' independently of one another represent hydrogen, alkyl , Cycloalkyl, heterocycloalkyl, aryl, hetaryl, WCOOR ^° , WCO ^O -M ⁺ , W (SO ₃ ) R ^° , W (SO ₃ ) ^- M ⁺ , WPO ₃ (R ^° ) (R ^p ), W (PO ₃ ) ^2– (M ⁺ ) ₂ , WNE ¹ E ² , W (NE ¹ E ² E ³ ) ⁺ X ^- , WOR ^° , WSR ^° , (CHR ^p CH ₂ O) _x R ^° , (CH ₂ NE ¹ ) _x R ^° , (CH ₂ CH ₂ NE ¹ ) _x R ^° , halogen, perfluoroalkyl, preferably trifluoromethyl, nitro, acyl or cyano, where W is a single bond, a heteroatom, a heteroatom-containing group or a divalent bridging group 1 to 20 bridge atoms, R ^° , E ¹ , E ² , E ³ each have the same or different radicals, selected below he is hydrogen, alkyl, cycloalkyl, acyl or aryl, R ^{p is} hydrogen, methyl or ethyl, M ^{+ is} a cation equivalent, X ^{- is} an anion equivalent and x is an integer from 1 to 240, two in each case neighboring radicals R ⁵ and R ⁶ and / or R ^{5 '} and R ^6' together with the carbon atoms of the pyrrole ring to which they are attached can also represent a condensed ring system with 1, 2 or 3 further rings. Compounds according to any one of the preceding claims, wherein R ^{3 is} selected from hydrogen, C ₁ -C ₆ alkyl, silyl and phenyl. Compound according to one of the preceding claims, wherein in the formula I the bridging group Y is selected from groups of the formulas III.a to III.t

wherein R ^I , R ^{I '} , R ^II , R ^II' , R ^III , R ^{III '} , R ^IV , R ^IV' , R ^V , R ^VI , R ^VII , R ^VIII , R ^IX , R ^X , R ^XI and R ^XII independently of one another for hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, hydroxy, thiol, polyalkylene oxide, polyalkyleneimine, alkoxy, halogen, SO ₃ H, sulfonate, NE ⁶ E ⁷ , alkylene-NE ⁶ E ⁷ , trifluoromethyl, nitro , Alkoxycarbonyl, carboxyl, acyl or cyano, in which E ⁶ and E ⁷ each represent the same or different radicals selected from hydrogen, alkyl, cycloalkyl and aryl, Z represents O, S, NR ¹⁵ or SiR ¹⁵ R ¹⁶ , where R ¹⁵ and R ¹⁶ independently of one another represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or Z represents a C ₁ -C ₄ alkylene bridge which has a double bond and / or an alkyl, cycloalkyl, heterocycloalkyl, aryl - Or can have hetaryl substituents, or Z represents a C ₂ -C ₄ alkylene bridge which is interrupted by O, S or NR ¹⁵ or SiR ¹⁵ R ¹⁶ , in which Groups of the formula III.a two adjacent radicals R ^I to R ^VI together with the carbon atoms of the benzene nucleus to which they are attached can also represent a condensed ring system with 1, 2 or 3 further rings, the groups of the formulas III .g to III.m two geminal residues R ^I , R ^{I '} ; R ^II , R ^{II '} ; R ^III , R ^{III '} and / or R ^IV , R ^{IV' can} also represent oxo or a ketal thereof, A ¹ and A ² independently of one another represent O, S, SiR ^a R ^b , NR ^c or CR ^d R ^e , where R ^a , R ^b and R ^c independently represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, R ^d and R ^e independently represent hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl or R ^d and R ^e together represent oxo or a ketal thereof, or the group R ^d together with another group R ^d or the group R ^e together with another group R ^{e form} an intramolecular bridging group D, D is a double-bonded bridging group, preferably selected from the groups

is in which R ⁹ , R ^{9 '} , R ¹⁰ and R ^10' independently of one another represent hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, carboxyl, carboxylate or cyano or together to form a 3- to 6-membered non-aromatic carbocycle are connected, R ¹¹ , R ¹² , R ¹³ and R ¹⁴ independently of one another for hydrogen, alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, COOH, carboxylate, cyano, alkoxy, SO ₃ H, sulfonate, NE ⁶ E ⁷ , alkylene NE ⁶ E ⁷ E ⁸⁺ X ^- , acyl or nitro, c is 0 or 1. Catalyst comprising at least one complex with a metal of subgroup VIII of the periodic table, which as Ligands at least one compound of formula I, as in one of the Expectations Defined 1 to 6 contains. The catalyst of claim 7, wherein the metal is selected made of cobalt, nickel, rhodium, ruthenium or iridium. Process for the hydroformylation of compounds, which contain at least one ethylenically unsaturated double bond by reaction with carbon monoxide and hydrogen in the presence of a Hydroformylation catalyst as in one of claims 7 or 8 defined. Process for the preparation of 2-propylheptanol, in which a) butene or a butene-containing C4-hydrocarbon mixture in the presence of a catalyst as defined in one of claims 7 or 8, with carbon monoxide and hydrogen to give an n-valeraldehyde hydroformylation product containing hydroformylated, b) optionally subjecting the hydroformylation product to a separation to obtain a fraction enriched in n-valeraldehyde, c) subjecting the hydroformylation product obtained in step a) or the fraction enriched in n-valeraldehyde obtained in step b) to an aldol condensation, d) the products of the aldol condensation are hydrogenated catalytically to give alcohols, and e) if appropriate, the hydrogenation products are subjected to a separation to obtain a fraction enriched in 2-propylheptanol. Process for the preparation of an ester mixture, wherein to obtain an alcohol mixture by a method as defined in claim 10, with at least an acid, the selected is among aliphatic di- and tricarboxylic acids, aromatic mono-, di- and tricarboxylic acids, phosphoric acid and derivatives and mixtures thereof. Use of a catalyst as in one of the Expectations 7 or 8 defined, for hydroformylation, carbonylation, hydrocyanation or hydrogenation.