MXPA06007882A - Continuous method for the production of linear pentene nitriles - Google Patents

Abstract

The invention relates to a method for continuous hydrocyanation of 1,3-butadiene in the presence of at least one nickel(0)-catalyst with chelate ligands, wherein 1,3-butadiene and cyanohydrogen are used in a molar ratio of 1,6 - 1,1 to 1.

Description

CONTINUOUS PROCEDURE FOR THE PREPARATION OF LINEAR PENTENONITRILS Description The present invention relates to a process for the continuous hydrocyanation of 1,3-butadiene in the presence of a nickel (0) catalyst.

Adiponitrile, an important intermediate in the production of nylon, is prepared by double hydrocyanation of 1,3-butadiene. In this case, 1,3-butadiene is first reacted with hydrocyanic acid in the presence of nickel (0), which is stabilized with phosphorus ligands, in pentenonitrile. Here a mixture of linear 3-pentenenitrile and branched pentenenitrile (2-methyl-3-butenonitrile) is formed. In a second process step, the branched pentenonitrile is isomerized in general in linear pentenonitrile. Finally, 3-pentenenitrile is hydrocyanated in the presence of a Lewis acid in adiponitrile.

Nickel-catalyzed (0) hydrocyanation of 1,3-butadiene in pentenonitriles in the absence of Lewis acids and the isomerization of 2-methyl-3-butenonitrile in 3-pentenenitrile with the aid of nickel (0), which is stabilized with ligands of phosphorus, is itself known.

Also the hydrocyanation catalysed with nickel (0) of 1,3-butadiene in pentenonitriles in the presence of Lewis acids is known. However, a non-selective formation of linear and branched dihitriles such as adiponitrile and methylglutardinitrile (WC Séidel, CA Toleman; York Academy of Science, Volume 415, Catalytic Transition Metal Hydrides, pages 201-221, 1983).

For the execution of a technical procedure, the selectivity of the different partial stages has a great economic and ecological importance, since, for example, the costs of the inputs used generally amount to 70% of production costs. The fact that the known methods achieve, despite the first non-selective hydrocyanation, total selectivities of more than 85%, thus being able to be executed in a technical and economic, lies mainly in the fact that the first hydrocyanation of 1,3-butadiene is stopped in the presence of Lewis acids in the hydrocyanate stage of the pentenenitriles and the unwanted branched pentenenitrile isomer can be transformed into the linear isomer wanted .

For the continuous synthesis of pentenonitriles from 1,3-butadiene and hydrocyanic acid, it is advantageous to use 1,3-butadiene to hydrocyanic acid in molar ratio of 1: 1, so that it is not necessary to recirculate 1, 3-but diene However, in this case it was found that, with such a method, the formation of undesired methylglutardinitrile is too great for an economical process.

In this way, it is an object of the present invention to provide a simple, selective, catalyst-protecting and continuous process for the hydrocyanation of 1,3-butadiene, in which the formation of methylglutardinitrile can be restricted to an acceptable amount.

This object is fulfilled by means of a procedure for. the continuous hydrocyanation of 1,3-butadiene in presence of at least one nickel (0) catalyst with chelate ligands. The process according to the invention is thus characterized in that 1, 3-butadiene and hydrocyanic acid can be used in a molar ratio of 1.6 to 1.1 to 1, preferably 1.6 to 1.3 to 1.

It was found according to the invention that by using nickel (0) catalysts with the ligands described below, a surplus of 1,3-butadiene restricts the formation of methylglutardinitrile. This test is contrary to the doctrine of Comparative Example 1 of WO 98/27054, where the use of a greater surplus of 1,3-butadiene leads to a lower selectivity of 1,3-butadiene.

As a catalyst in the process according to the invention, a homogeneously dissolved catalyst is preferably used. With special preference, nickel (0) catalysts dissolved homogeneously are used. The nickel (0) catalysts of particular preference are stabilized with phosphorus chelate ligands.

The chelate ligands are selected, with particular preference, from the group consisting of phosphites, phosphines, phosphonites, phosphinites and bidentate phosphinit phosphites.

The chelate ligands have, with special preference, the general formula (I) in which X11, X12, X13, X21, X22, X23 mean, independently of each other, oxygen or a single bond, R11, R12 signify, independently of one another, identical or different organic radicals, simple or compound bridged, R1, R2 signify, independently of one another, identical or different organic radicals, simple or compound bridged, And it means a bridge group.

By compound I is meant, for the purposes of the present invention, a simple compound or a mixture of various compounds of the above-mentioned formula.

In a preferred embodiment, X11, X12, X13, X21, X22, X23 can represent oxygen. In this case, the bridge group Y is linked with phosphite groups.

In another preferred embodiment, X11 and X12 may represent oxygen 'X13, a single bond, or X11 and X13 represent oxygen and X12, a single bond, so that the phosphorus atom surrounded by X11, X12 and X13 is the oxygen atom. central atom of a phosphonite. In this case, X21, X22 and X23 can represent oxygen, either X21 and X22 represent oxygen and X23 a single bond, or X21 and X23 represent oxygen and X22 a single bond, or X23 represent oxygen and X21 and X22 represent a link simple, or X21 represent oxygen and X22 and X23 a single bond, or X21, X22 and X23 represent a single bond, so that the phosphorus atom surrounded by X21, X22 and X23 is the central atom of a phosphite, a phosphonite, a phosphinite or a phosphine, preferably a phosphonite.

In another preferred embodiment, X13 can represent oxygen and X11 and X12 represent a single bond, or X11 represent oxygen and X12 and X13 represent a single bond, so that the phosphorus atom surrounded by X11, X12 and X13 is the central atom of a phosphonite. In such a case, X21 ', X22 and X may represent oxygen, or X23 represent oxygen and X21 and X22 a single bond, or X21 represent oxygen and X22 and X23 a single bond, or X21, X22 and X23 represent a link simple, so that the phosphorus atom surrounded by X21, X22 and X23 is the central atom of a phosphite, a phosphinite or a phosphine, preferably a phosphinite.

In another preferred embodiment, X11, X12 and X13 may represent a single bond, such that the phosphorus atom surrounded by X11, X12 and X13 is the central atom of a phosphine. In this case, X21, X22 and X23 can represent oxygen, or X21, X22 and X23 represent a single bond, so that the phosphorus atom surrounded by X21, X22 and X23 is the central atom of a phosphite or a phosphine , preferably of a phosphine.

As the bridge group Y, preference is given to aryl groups substituted, for example, with Ci-C4 alkyl, halogen such as fluorine, chlorine, bromine, halogenated alkyl such as trifluoromethyl, aryl such as phenyl, or unsubstituted aryl groups , preferably those having from 6 to 20 carbon atoms within the aromatic system, in particular pyrocatechol, bis (phenol) or bis (naphthol).

The radicals R11 and R12 can represent, independently of one another, identical or different organic residues. It is considered advantageous that as radicals R11 and R12 aryl radicals are taken into account, preferably those having from 6 to 10 carbon atoms, and which can be unsubstituted or substituted once or several times, in particular with Ci-C4 alkyl, halogen as fluorine, chlorine, bromine, halogenated alkyl as trifluoromethyl, aryl as phenyl, or with unsubstituted aryl groups.

The radicals R21 and R22 can represent, independently of one another, identical or different organic residues. It is considered advantageous that, as radicals R21 and R22, aryl radicals, preferably those having 6 to 10 carbon atoms, and which may be unsubstituted or substituted one or more times, in particular with C?-C4 alkyl, are considered. , halogen as fluorine, chlorine, bromine, halogenated alkyl as trifluoromethyl, aryl as phenyl, or with unsubstituted aryl groups.

The radicals R11 and R12 can be simple or compounds bridged. Also the radicals R and R can be simple or compounds linked by bridges. The radicals R11, R12, R21 and R22 may all be simple, two compounds joined by bridges and two simple, or all compounds bridged together, in the manner in which it has been described.

In a particularly preferred embodiment, the compounds of the formulas I, II, are taken into account, III, IV and V mentioned in US 5,723,641. In a particularly preferred embodiment, the compounds of the formulas I, II, III, IV, V, VI and VII mentioned in US 5,512,696, in particular, those applied therein in examples 1 to 31. In a particularly preferred embodiment, the compounds of the formulas I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV and XV mentioned in US 5,821,378, in particular, those applied there in Examples 1 to 73.

In a particularly preferred embodiment, the compounds of the formulas I, II, III, IV, V and VI mentioned in US Pat. No. 5,512,695, in particular those applied therein in examples 1 to 6. In a particularly preferred embodiment, the compounds of formulas I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII and XIV are taken into account mentioned in US 5,981,772, in particular, those applied there in Examples 1 to 66.

In a particularly preferred embodiment, the compounds mentioned in US 6,127,567 and applied therein in examples 1 to 29 are taken into account. In a particularly preferred embodiment, the compounds of the formulas I are taken into account , II, III, IV, V, VI, VII, VIII, IX and X mentioned in US 6,020,516, in particular, those applied therein in examples 1 to 33. In a particularly preferred embodiment, they are into account the compounds mentioned in US Pat. No. 5,959,135, and applied therein in Examples 1 to 13.

In a particularly preferred embodiment, the compounds of the formulas I, II and III mentioned in document 5,847,191 are taken into account. In a particularly preferred embodiment, the compounds mentioned in US Pat. No. 5,523,453 are taken into account, especially the compounds represented therein in formulas 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 and 21. In a particularly preferred embodiment, the compounds mentioned in WO 01/14392 are taken into account, preferably the compounds represented in formulas V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XXI, XXII, XXIII.

In a particularly preferred embodiment, the compounds mentioned in WO 98/27054 are taken into account. In a particularly preferred embodiment, the compounds mentioned in WO 99/13983 are taken into account. In a particularly preferred embodiment, the compounds mentioned in WO 99/64155 are taken into account.

In a particularly preferred embodiment, the compounds mentioned in the German patent application DE 100 380 37 are taken into account. In a particularly preferred embodiment, the compounds mentioned in the German patent application DE are taken into account 100 460 25. In a particularly preferred embodiment, the compounds mentioned in the German patent application DE 101 502 85- are taken into account.

In a particularly preferred embodiment, the compounds mentioned in the German patent application DE 101 502 86 are taken into account. In a particularly preferred embodiment, they are taken into account the compounds mentioned in the German patent application DE 102 071 65. In another particularly preferred embodiment of the present invention, the ligands of phosphorus chelates mentioned in US 2003/0100442 Al are taken into account.

In another particularly preferred embodiment of the present invention, the phosphorus chelate ligands mentioned in the previously published German patent application DE 103 50 999.2 are taken into account. /30/2003.

These compounds (I) and their preparation are known per se.

As the phosphorus ligand, mixtures containing the compounds (I) can also be used.

Hydrocyanation can also be carried out optionally in the presence of additional monodentate phosphorus ligands. These monodentate phosphorus ligands are preferably selected from the group consisting of phosphines, phosphites, phosphinites and phosphonites.

These monodentate phosphorus ligands preferably have the formula (II) P ^ R1) (X2R2) (X3R3) (II) By compound II is meant, in the sense of the present invention, a single compound or a mixture of various compounds of the above formula.

According to the invention, X1, X2, X3 are, independently of one another, oxygen or a single bond. In case all the groups X1, X2 and X3 represent simple bonds, the compound II represents a phosphine of the formula P (RZR2R3) with the meanings given to R1, R2 and R3 in this description.

In case two of the groups X1, X2 and X3 represent simple bonds and one represents oxygen, the compound II represents a phosphinite of the formula PIR1) (R2) (R3) or P (RX) (OR2) (R3) or P (R1) (R2) (OR3) with the meanings indicated for R1, R2 and R3 below.

In case one of the groups X1, X2 and X3 represents n single bond and two represent oxygen, compound II represents a phosphonite of the formula PÍOR1) (OR2) (R3) or P (RX) (OR2) (OR3) or P (ORx) (R2) (OR3) with the meanings given for R1, R2 and R3 in this description.

In a preferred embodiment, all groups X1, X2 and X3 should represent oxygen, so that compound II profitably represents a phosphite of the formula P (OR1) (OR2) (OR3) with the meanings indicated for R1 , R2 and R3 later.

According to the invention, R1, R2 and R3 represent, independently of one another, identical or different organic radicals. As R.sub.1, R.sub.2 and R.sub.3 are independently selected from each other, alkyl radicals, preferably having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, aryl groups, such as phenyl, o-tolyl, m-tolyl, p-tolyl, 1-naphthyl, 2-naphthyl, or hydrocarbyl, preferably with 1 to 20 carbon atoms, such as 1 , l'bifenol, 1, l'binaftol. The groups R1, R2 and R3 can be linked together directly with one another, ie not through the central phosphorus atom. Preferably, the groups R1, R2 and R3 are not directly linked to one another.

In a preferred embodiment, radicals selected from the group consisting of phenyl, o-tolyl, m-tolyl and p-tolyl are taken into account as groups R1, R2 and R3. In a particularly preferred embodiment, they should, in such a case, be phenyl groups at most two of the groups R1, R2 and R3.

In another preferred embodiment, in such a case, at least two of the groups R1, R2 and R3 should be o-tolyl groups.

As particularly preferred compounds II, those of the formula Il-a can be applied (o-tolyl-O-) w (m-tolyl-O-) x (p-tolyl-O-) and (phenyl-O-) z P (II- a) meaning w, x, y and z a natural number and the following conditions are in force: w + x + y + z = 3 y, z 2- Compounds II a of that kind are for example (p-tolyl-O-) (phenyl-O-) 2P, (m-tolyl-O) (phenyl-O-) 2P, (o-tolyl-0-) (phenyl) -O-) 2P, (p-tolyl-O-) 2 (phenyl-O-) P, (m-tolyl-0-) 2 (phenyl-0-) P, (o-tolyl-O-) 2 ( phenyl-O-) P, (m-tolyl-O-) (p- tolyl-O-) (phenyl-O-) P, (o-tolyl-O-) (p-tolyl-O-) (phenyl-O) P, (o-tolyl-O-) (m-tolyl-O -) (phenyl-O-) P, (p-tolyl-O-) 3P, (m-tolyl-O-) (p-tolyl-O-) 2P, (o-tolyl-O-) (p-tolyl -O-) 2P, (m-tolyl-0-) 2 (p-toluyl-0-) P, (o-tolyl-O-) 2 (p-tolyl-O-) P, (o-tolyl-O) -) (m-tolyl-O-) (p-tolyl-O) P, (m-tolyl-O) 3P, (o-tolyl-0-) (m-tolyl-O) 2P (o-tolyl-O) ) 2 (m-tolyl-O) P, or mixtures of those compounds.

Mixtures containing (m-tolyl-O-) 3P, (m-tolyl-O-) 2 (p-tolyl-O-) P, (m-tolyl-0-) (p-tolyl-O-) 2P, and (p-tolyl-O-) 3P can be obtained, for example, by reacting a mixture containing m-cresol and p-cresol, in particular, in a 2: 1 molar ratio, such as is produced in the distillation process of petroleum, with a phosphorus trihalogenide, such as phosphorus trichloride.

In another, equally preferred embodiment, the phosphites of the formula IIb described in more detail in DE-A 199 53 058 are considered as phosphorus ligands: P (O-R1) (0-R2) and (0-R3) z (0-R4) p (II b) being R1: an aromatic radical with a C? -C? 8 alkyl substituent, in position or with respect to the oxygen atom linking the phosphorus atom with the aromatic system, or with an aromatic substituent in position or with respect to the oxygen atom that joins the phosphorus atom with the aromatic system, or with an aromatic system condensed in position or with respect to the oxygen atom that joins the phosphorus atom with the aromatic system, R2: an aromatic radical with an alkyl substituent C? -C? 8, in position m with respect to the oxygen atom joining the phosphorus atom with the aromatic system, or with an aromatic substituent in position m with respect to the oxygen atom which joins the phosphorus atom with the aromatic system, or with an aromatic system condensed in position m with respect to the oxygen atom that joins the phosphorus atom with the aromatic system, carrying the "aromatic radical in position or with respect to the atom of oxygen that binds the phosphorus atom with the aromatic system, a hydrogen atom, R3: an aromatic radical with a C1-C8 alkyl substituent, in position p with respect to the oxygen that joins the phosphorus atom with the aromatic system, or with an aromatic substituent in position p with respect to the oxygen atom that joins the phosphorus atom with the aromatic system, carrying the aromatic radical in position or with respect to the atom of oxygen that binds the phosphorus atom with the aromatic system, a hydrogen atom, R4: an aromatic radical that carries, in position 10 o, ni and p with respect to the oxygen atom linking the phosphorus atom with the aromatic system, other substituents than those defined for R1, R2 and R3, carrying the aromatic radical in position or with respect to the oxygen atom that joins the phosphorus atom with the aromatic system, a hydrogen atom, X: 1 or 2, Y i z, p: independently of each other, 0, l or 2, with the proviso that x + y + z + p = 3.

Preferred phosphites of formula II b can be seen in DE-A 199 53 058. As radical R 1, o-tolyl, o-ethyl-phenyl groups advantageously come into account, o-n-propyl-phenyl, o-isopropyl-phenyl, o-n-butyl-phenyl, o-sec-butyl-phenyl, o-tert-butyl-phenyl, (o-phenyl) -phenyl or 1-naphthyl.

As radical R2, m-tolyl, m-ethyl phenyl, mn-propyl-phenyl, m-isopropyl-phenyl, mn-butyl-phenyl, m-sec-butyl-phenyl, m-tert-butyl-phenyl, (m-phenyl) -phenyl or 2-naphthyl.

As radical R3, p-tolyl, p-ethyl-phenyl, pn-propy1-phenyl, p-isopropyl-phenyl, p-butyl-phenyl, p-sec-butyl-phenyl, p-tert-butyl-phenyl, advantageously enter. or (p-phenyl) -phenyl.

The radical R is preferably phenyl. Preferably, p is equal to 0. For the indices x, y, z and p in compound II b the following possibilities are given: Preferred phosphites of formula II b are those in which p is equal to zero and R1, R2 and R3 are, independently of one another, selected from o-isopropyl-phenyl, m-tolyl and p-tolyl, and R4 It is phenyl.

Particularly preferred phosphites of the formula II b those in which R1 is the o-isopropyl-phenyl radical, R2 is the m-tolyl radical and R3 is the p-tolyl radical, with the indices indicated in the table above; in addition they are those in which R1 is the o-tolyl radical, R2 is the m-tolyl radical and R3 is the p-tolyl radical, with the indices indicated in the table; also those in which R1 is the 1-naphthyl radical, R2 is the m-tolyl radical and R3 is the p-tolyl radical, with the indices indicated in the table; also those in which R1 is the o-tolyl radical, R2 is the 2-naphthyl radical and R3 is the p-tolyl radical, with the indices indicated in the table; and finally those in which R1 is the o-isopropyl-phenyl radical, R2 is the 2-naphthyl radical and R3 is the p-tolyl radical, with the indices indicated in the table; as well as mixtures of those phosphites.

The phosphites of the formula II b can be obtained a) by reacting a phosphorus trihalogenide with an alcohol selected from the group consisting of R 10 H, R 20 H, R 30 H and R 4 OH, or mixtures thereof, thus obtaining a monoester of dihalogeno-phosphorous acid, b) by reacting said monoester of dihalogeno-phosphorous acid with an alcohol selected from the group consisting of R ^ H, R2OH, R30H and R40H, or mixtures of these, thereby obtaining a diester of monohalo-phosphorous acid, and c) by reacting said diester of monohalo-phosphorous acid with an alcohol selected from the group consisting of R x H, R 2 OH, R 30 H and R 40 H, or mixtures of these, thereby obtaining a phosphite of the formula Il-b.

The reaction can be carried out in three separate steps. Likewise, two of these three steps can be combined, that is a) with b) or b) with c). As an alternative, the three steps a), b) e) can be combined.

By doing so, appropriate parameters and appropriate amounts of alcohols selected from the group consisting of R 1 OH, R 2 OH, R 3 OH and ROH, or mixtures thereof, can be easily determined by some simple preliminary tests.

As a phosphorus trihalogenide, all phosphorus trihalogenides are taken into account, preferably those in which they are applied, such as halide, Cl, Br, I, in particular Cl, as well as mixtures of these. It is also possible to use, as phosphorus trihalide, mixtures of halogen-substituted phosphines in the same or different manner. PC13 is particularly preferred. Further details regarding the reaction conditions in the preparation of the phosphites II b and in terms of processing are given in DE-A 199 53 058.

The phosphites II b can also be used as a mixture of various phosphites II b as ligands. A mixture of this kind can occur, for example, in the preparation of phosphites II b.

In a particularly preferred embodiment of the process according to the invention, the phosphorus ligand additional monodentate of the nickel (0) complex and / or the additional monodentate free phosphorus ligand is selected from tritolylphosphite, as well as the phosphites of the formula IIb P (O-R ^ x (0-R2) (0-R3) z (0-R4) p (II b) wherein R1, R2 and R3 are selected, independently from each other, of o-isopropyl-phenyl, m-tolyl and p-tolyl, R4 is phenyl; x is = l or 2, e y, z, p are, independently of each other, 0, 1 or 2, with the proviso that x + y + z + p = 3; and its mixtures.

The compounds I, II, II a and II b described, as well as their preparation, are known per se. As a further monodentate phosphorus ligand, in addition to a chelate ligand of the formula I or a mixture of several chelate ligands of the formula I, mixtures containing at least two of the compounds II, II a and II b can also be used.

Hydrocyanation can be carried out in the presence or absence of a solvent. When a solvent is used, it must be liquid at the given reaction temperature and the reaction pressure given and inert to the unsaturated compounds and at least one catalyst. In Generally, hydrocarbons are used as solvents, for example, benzene or xylene, or nitriles, for example, acetonitrile or benzonitrile. However, as a solvent, a ligand is preferably used. It is also possible to use several ligands, such as two or three.

The catalysts used in the process according to the invention can be prepared, for example, by reductive synthesis of catalysts. For this purpose, a nickel (II) source is reacted with the ligand according to methods of general knowledge, as described for example in US 6,127,567 and the references cited therein, as well as the German patent applications DE 103 51 000.1, DE 103 51 002.8 and DE 103 51 003.6 of the company BASF AG, in the nickel complex (0).

A preferred embodiment of the reductive synthesis of nickel catalysts is described in the German patent application DE 103 51 000.1 prior to the previously not previously published priority entitled "Verfahren zur Herstellung von Nickel (0) -Phosphorligand-Komplexen" of the company BASF AG. Accordingly, the preparation of the nickel (0) catalyst is carried out by reducing an adduct of nickel (II) -ether in the presence of minus a phosphorus ligand. The nickel (II) -ether adduct to be used for this purpose is preferably prepared by dissolving a nickel halide in water, mixing with an ether and an organic nitrile, optionally under stirring and subsequently separating the water and optionally the ether. The nickel (II) -ether adduct is preferably anhydrous and contains, in a preferred embodiment, a nickel halide. Nickel chloride, nickel bromide and nickel iodide are considered as nickel halide. Nickel chloride is preferred. The nickel (II) -ether adduct used preferably comprises an ether containing oxygen, sulfur or a mixture of oxygen and sulfur. It is preferably selected from the group consisting of tetrahydrofuran, dioxane, diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, di-sec-butyl ether, ethylene glycol alkyl ether, diethylene glycol alkyl ether and triethylene glycol alkyl ether. Ethylene glycol dimethyl ether (1,2-dimethoxyethane, glyme) and ethylene glycol diethyl ether are preferred as ethylene glycol alkyl ether. As diethylene glycol alkyl ether, it is preferred to use diethylene glycol dimethyl ether (diglyme). As triethylene glycol alkyl ether, it is preferred to use triethylene glycol dimethyl ether (triglyme).

The reducing agent used to prepare the nickel (0) complex is preferably selected from the group consisting of metals that are more electropositive than nickel, metal alkyls, electric current, complex hydrides and hydrogen.

In another embodiment, the nickel (0) catalyst can be prepared by means of a process which is described in the German patent application DE 103 51 002.8 prior to the previously not previously published priority entitled "Verfahren zur Herstellvon Nickel ( 0) -Phosphorligand-Komplexen "from BASF AG. Accordingly, the preparation of the nickel complex (0) is carried out by reducing a nickel (II) source, which contains nickel bromide, nickel iodide or mixtures thereof, in the presence of at least one phosphorus ligand. In this case, the nickel (II) source is preferably used without special pre-drying. It is preferred that the preparation be carried out in this case preferably in a solvent which is selected from the group consisting of organic nitriles, aromatic or aliphatic hydrocarbons or their mixtures. As reducing agents, metals which are more electropositive than nickel are preferably used. In the same way, it is also possible to use metal alkyls, electric current, complex hydrides or hydrogen.

Beyond this, the nickel (0) catalyst used in the process according to the invention can also be prepared according to a process that is described in the German patent application DE 103 51 003.6 prior to the previously not previously published priority entitled " Einsatz von azeotrop-getrocknetem Nickel (II) -Halogenide " of the company BASF AG. Accordingly, the preparation of the nickel-complex (0) is carried out by reducing a hydrated nickel (II) halide dried by azeotropic distillation in the presence of at least one phosphorus ligand. The nickel halide (II) is preferably selected of the group consisting of nickel (II) chloride, nickel (II) bromide and nickel (II) iodide. The nickel halide (II) dried by azeotropic distillation is preferably prepared by a process for removing water from the corresponding nickel halides hydrated, Wherein the mixture is combined with a diluent whose boiling point in the case of the non-azeotropic formation of the aforementioned diluent with water under the pressure conditions of the aforementioned distillation is greater than the boiling point of the water and which is in liquid state j¡- at this boiling point of water or forming a azeotrope or heteroaztrope with water under the conditions of pressure and temperature of the distillation mentioned later, and the mixture containing the hydrolyzed nickel (II) halide and the diluent is distilled, under separation of the aforementioned azeotrope or aforementioned heteroazeotrope from this mixture and obtaining an anhydrous mixture containing nickel (II) halide and said diluent. The diluent used is preferably an organic diluent with at least one nitrile group. The reduction to prepare the corresponding nickel (0) complex is preferably produced by metals that are more electropositive than nickel. Alternatively, it is also possible to use metallic alkylene, electric current, metal hydrogen hydrides.

The ligand used in the processes according to the patent applications described DE 103 51 000.1, DE 103 51 002.8 and DE 103 51 003.6 may also exist in a solution of ligands that has already been applied as a catalyst solution in hydrocyanation reactions and thus is impoverished in nickel (0).

Hydrocyanation can be carried out in any appropriate device, known to the skilled person. For In this way, the conventional equipment is taken into account, as described, for example, in: Kirk-Othmer, Encyclopedia of Chemical Technology, 4th Ed., Vol. 20, John Wiley & Sons, New York, 1996, pages 1040 to 1055, such as agitation boiler reactors, bubble reactors with loop circulation, reactors with gas circulation, bubble columns or tubular reactors, in each case eventually with devices to dissipate the heat of the reaction. The reaction can be carried out in several teams, such as in two or three.

In a preferred embodiment of the method according to the invention, reactors with a characteristic of remixing or cascades of reactors with characteristics of remixing were advantageous. The cascades of reactors with a remixing characteristic that are operated with a transverse current with respect to the dosage of hydrocyanic acid were particularly advantageous.

Preferably, the hydrocyanation is carried out continuously in one or several process steps under agitation. If several process steps are used, then it is preferred that the process steps be connected in series. In this case, the product is passed directly from one stage of the procedure to the next procedure stage. The hydrocyanic acid can be added directly in the first stage of the process or between the various stages of the process.

The reaction is preferably carried out at absolute pressures from 0, -1 to 500 MPa, particularly preferably 0.5 to 50 MPa, especially 1 to 5 MPa. The reaction is preferably carried out at temperatures of 273 to 473 K, with particular preference 313 to 423 K, in particular 333 to 393 K. In this case, average waiting times of the liquid phase of the reactor in the range of 0.001 to 100 hours, preferably from 0.05 to 20 hours, with special preference from 0.1 to 5 hours, in each case per reactor.

The reaction can be carried out in a liquid phase embodiment in the presence of a gas phase and optionally a suspended solid phase. In this case, the starting substances can be hydrocyanic acid and 1,3-butadiene, in each case in a liquid or gaseous state.

The reaction can be carried out in another embodiment in liquid phase, wherein the pressure in the reactor is measured in such a way that they are added in the state All the educts, such as 1,3-butadiene, hydrocyanic acid and at least one catalyst, are liquid and are in the reaction mixture in the liquid phase. In this case there can be a solid phase suspended in the reaction mixture which can also be dosed together with at least one catalyst, for example, composed of degradation products of the catalyst system containing, among others, nickel compounds (II). ).

In a preferred embodiment, the process according to the invention is characterized in that the continuous hydrocyanation is carried out in the presence of at least one Lewis acid.

According to the invention it was found that, by using an excess of 1,3-butene, the presence of a Lewis acid does not lead to the formation of dinitriles known in the literature for monophosphite complexes in the form of methylglutardinitrile. The results obtained with the process according to the invention are comparable with those without the addition of Lewis acid.

The method according to the invention is characterized in a preferred embodiment by the following < - stages of procedure: (a) continuous hydrocyanation of 1,3-butadiene in the presence of at least one nickel (0) catalyst with chelate ligands and optionally in the presence of at least one Lewis acid, wherein 1,3-butadiene and hydrocyanic acid in a ratio of 1.6 to 1.1 to 1, preferably 1.6 to 1.3 to 1, and a mixture 1 is obtained which contains 3-pentenenitrile and 2-methyl-3-butenonitrile; . (c) continuous isomerization of 2-methyl-3-butenonitrile, which is contained in mixture 1, in at least one isomerization catalyst dissolved or dispersed in 3-pentenenitrile, resulting in mixture 2.

According to the invention, isomerization is carried out in the presence of a system comprising a) nickel (0), b) a compound complexed with nickel (0) as a ligand, containing triple-bond phosphorus and eventually c) a Lewis acid.

The preparation of catalyst systems containing nickel (0) can be carried out according to processes known per se.

As ligands for the isomerization catalyst, the same phosphorus ligands as for the hydrocyanation catalyst can be used. Thus, in a preferred embodiment of the method according to the invention, the isomerization catalyst used in process step (c) is the nickel (0) catalyst with chelate ligands used in the process step (a) .

In addition, the system optionally contains a Lewis acid. The use of a Lewis acid in the isomerization of 2-methyl-3-butenenitrile leads to an increase in the reaction rate. With this, the reduction of the reaction temperature is allowed and thus the thermal load of the catalyst is reduced.

In the sense of the present invention, Lewis acid is understood as a single Lewis acid or a mixture of several Lewis acids, such as two, three or four.

As Lewis acid, account is taken, in this case, of inorganic or organic metal compounds, in which the cation is selected from the group consisting of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron. , aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium and tin. Examples are ZnBr2, ZnL2, ZnCl2, ZnS0, CuCl2, CuCl, Cu (03SCF3) 2, CoCl2, CoI2, Fel2, FeCl3, FeCl2, FeCl2 (THF) 2, TiCl4 (THF) 2, TIC14, TiCl3, ClTi (0- i-propyl) 3, MnCl2, ScCl3, A1C13, (C8H17) A1C12, (C8H17) 2A1C1, (I-C4H9) 2A1C1, (CdH5) 2AlCl, (CSH5) A1C12, ReCl5 / ZrCl4, NbCl5, VC13, CrCl2, M0Cl5, YCl3, CdCl2, LaCl3, Er (03SCF3) 3, Yb (02CCF3) 3, SmCl3, B (CeH5) 3, TaCl5, as described for example in US 6,127. 567, US 6,171,996 and US 6,380,421. In addition, metal salts such as ZnCl2, CoI2 and SnCl2 are taken into account, as well as organometallic compounds such as RA1C12, R2A1C1, RSn03SCF3 and R3B, where R is an alkyl or aryl group, as described for example in US Pat. 3,496,217, US 3,496,218 and US 4,774,353. On the other hand, a metal in cationic form, selected from the group consisting of zinc, cadmium, beryllium, aluminum, gallium, indium, thallium, titanium, zirconium, hafnium, erbium, can be used as a promoter in the form of a promoter. , germanium, tin, vanadium, niobium, scandium, chromium, molybdenum, tungsten, manganese, rhenium, palladium, thorium, iron and cobalt, preferably zinc, cadmium, titanium, tin, chromium, iron and cobalt, wherein the anionic part of the compound can be selected from the group consisting of halides, such as fluoride, chloride, bromide and iodide, anions of lower fatty acids with to 7 carbon atoms, HP032", H3P02 ', CF3C00 ~, C7H? 50S02 ~ or S042X Also mentioned in US 3,773,809 as suitable promoters borhydrides, organoborhydrides and boric acid esters of the formula R3B and B (OR ) 3, wherein R is selected from the group consisting of hydrogen, aryl radicals with 6 to 18 carbon atoms, aryl radicals substituted with alkyl groups with 1 to 7 carbon atoms and aryl radicals substituted with alkyl groups substituted with cyano with 1 at 7 carbon atoms, advantageously triphenylboron. In addition, as described in US 4,874,884, synergistic efficacy combinations of Lewis acids can be employed in order to raise the activity of the catalyst system. Suitable promoters can be selected from the group consisting of CdCl2, FeCl2, ZnCl2, B (CSH5) 3 and (CsH5) 3SnX, with X = CF3S03, CH3CsH4S03 or (CSH5) 3BCN, where for the ratio of promoter to nickel an interval is mentioned preferably from about 1:16 to about 50: 1.

For the purposes of the present invention, the term "Lewis acid" also includes the promoters mentioned in US 3,496,217, US 3,496,218, US 4,774,353, US 4,874,884, US 6,127,567, US 6,171,996. and US 6,380,421.

Particularly preferred Lewis acids are metal halides, especially fluorides, chlorides, bromides, iodides, especially chlorides, which are particularly preferred, in particular, especially metal salts, especially metal halides. , zinc chloride, iron (II) chloride and iron (III) chloride.

The isomerization can be carried out in the presence of a liquid diluent, - for example a hydrocarbon, such as hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, decahydronaphthalene - for example an ether, such as diethyl ether, tetrahydrofuran, dioxane, glycol dimethyl ether, anisole, - for example an ester, such as ethyl acetate, methyl benzoate, or - for example a nitrile, such as acetonitrile, benzonitrile, or - mixtures of these diluents.

In a particularly preferred embodiment, isomerization is taken into account in the absence of such a liquid diluent.

In addition, it was found advantageous when the isomerization and / or the hydrocyanation are carried out in an atmosphere of non-oxidizing effect, for example under an atmosphere of nitrogen shielding gas or a noble gas, for example argon. In this case, isomerization and / or hydrocyanation are preferably carried out under the exclusion of moisture.

The isomerization can be carried out in any appropriate device, known to the skilled person. For isomerization, conventional equipment is thus taken into account as described, for example, in: Kirk-Othmer, Encyclopedia of Chemical Technology, 4th Ed., Vol. 20, John Wiley & Sons, New York, 1996, pages 1040 to 1055, such as agitator boiler reactors, bubble reactors with loop circulation, reactors with gas circulation, bubble columns or tubular reactors. The reaction can be carried out in several teams, such as in two or three.

In a preferred embodiment of the method according to the invention, the isomerization is carried out in a compartmentalized tubular reactor.

In another preferred embodiment of the method according to the invention, the isomerization is carried out in at least two reactors connected in series, wherein the first reactor has essentially a characteristic of a stirring boiler and the second reactor is designed in such a way that it presents essentially characteristic of tube.

In a particularly preferred embodiment of the process according to the invention, the isomerization is carried out in a reactor, wherein the reactor has the characteristic of a cascade of stirring boilers which is equivalent to 2 to 20 stirring boilers, in particular 3 to 10 stirring boilers.

The isomerization is preferably carried out at an absolute pressure of 0.1 mbar at 100 bar, particularly preferably 1 mbar at 16 bar, especially 10 mbar at 6 bar. The temperature is in this case preferably 80 to 125 ° C, especially preferably 85 to 120 ° C, especially 90 to 115 ° C.

In a particularly preferred embodiment of the method according to the invention, the following process step (b) is carried out between process steps (a) and (c): (b) Distillative separation of 1,3-butadiene from mixture 1.

According to the invention it was found that 1,3-butadiene acts as an inhibitor in the isomerization of 2-methyl-3-butenonitrile. "Therefore, it is particularly preferred from the process that 1,3-butadiene is separated before isomerization.

In a particularly preferred embodiment of the process according to the invention, the 3-pentenenitrile obtained by the process according to the invention in process step (c), optionally after an isomerization of the 2-methyl-3-butenonitrile obtained in parallel according to the embodiment described above is subjected to further hydrocyanation in the presence of at least one Lewis acid in adiponitrile. The procedural conditions that must be applied in this case are known per se. Also in this hydrocyanation a nickel (0) catalyst with phosphorus ligands is used. Thus it is offered for an economic process to connect the circuits of the catalysts used in the different hydrocyanations with one another, so that the same catalyst system as in the first hydrocyanation is also used in the second hydrocyanation. A corresponding mode of procedure is described in DE-A-102 004 004 682. Since the process according to the invention allows a hydrocyanation of 1,3-butadiene with Lewis acid, an expensive quantitative separation of the acid is not necessary. of Lewis predicted hitherto from the second hydrocyanation of 3-pentenenitrile prior to the use in the first hydrocyanation of 1,3-butadiene by applying an excess of 1,3-butadiene. Thus, a simple extraction for the separation of the dinitrile after the second hydrocyanation is preferably sufficient in the present invention.

In case an isomerization is carried out, it is especially preferred that in the first and in the second hydrocyanation as in the isomerization that the same catalyst system be used. By the possibility of admitting a Lewis acid in the first hydrocyanation without loss of selectivity, the extraction of the catalysts can be reduced.

The present invention is explained in more detail by means of the following exemplary embodiments.

Example: Continuous Hydrocyanation of BD in 2M3BN / 3PN In the examples the following abbreviations are used: HCN: 3PN hydrocyanic acid: 3-pentenenitrile MGN: methylglutardinitrile 2M3BN: 2-methyl-3-butenonitrile BD: 1,3-butadiene THF: tetrahydrofuran Ligando 1 Example 1: (BD / HCN ratio = l / l) C. 1.65 mol of 1,3-butadiene, 1.65 mol of HCN and 4 mmol of Ni are introduced per hour in the form of a catalyst solution, composed of 1 mmol of Ni (0), 2 mmol of ligand 1 and 4 mmol of m- / p-tolylphosphite, dissolved in 3-pentenenitrile, in a pressure reactor (pressure: 15 bar, internal temperature 90 ° C, waiting time: '40 min / reactor). The production of HCN is quantitative according to the volumetric analysis (titration according to Vollhardt). The 2M3BN / 3PN ratio of the product of the reaction is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 0.76. The yield for HCNes is 87.7% pentenenitrile, 10.4% MGN, 1.7% 2M2BN.

Example 2: (BD / HCN ratio = 1.25 / 1) Hourly 1.9 mol of 1,3-butadiene, 1.5 mol of HCN and 5.4 mmol of Ni are introduced in the form of a catalyst solution, composed of 1 mmol of Ni (0), 2 mmol of ligand 1 and 4 mmol of m- / p-tolylphosphite, dissolved in 3-pentenenitrile, in a pressure reactor (pressure: 15 bar, internal temperature 90 ° C, waiting time: 40 min / reactor). The production of HCN is quantitative according to the volumetric analysis (titration according to Vollhard). The 2M3BN / 3PN ratio of the reaction product is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 0.73. The yield for HCN is 94.6% pentenenitrile, 4.0% MGN, 1.3% 2M2BN.

Example 3: (BD / HCN ratio = 1.5 / 1) Per hour, 2.45 mol of 1,3-butylene, 1.65 mol of HCN and 4 mmol of Ni are introduced in the form of a catalyst solution, composed of 1 mmol of Ni (0), 2 mmol of ligand 1 and 4 mmol of m- / p-tolylphosphite, dissolved in 3-pentenenitrile, in a pressure reactor (pressure: 15 bar, internal temperature 90 ° C, waiting time: 33 min / reactor). The production of HCN is quantitative according to the volumetric analysis (titration according to Vollhard). The 2M3BN / 3PN ratio of the product of the reaction is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 0.73. The yield for HCN is 95.9% pentenenitrile, 1.3% MGN, 2.1% 2M2BN.

Example: Synthesis and isomerization of a continuous reactor product Example 4: (without butadiene separation) From a catalyst solution composed of 0.56% Ni (0), 62.2% of 3PN and 37.24% of ligand 1, 2 mmol of Ni (0) are extracted, mixed with 611 mmol of BD, filled at 25 ° C in a glass autoclave and heated to 90 ° C. They are now dosed for 81 min. 400 mmol of HCN in THF is stirred for a further 60 min. at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The 2M3BN / 3PN ratio is also determined by gas chromatography (percentage by GC surface). The ratio '2M3BN / 3PN is 1 / 1.36.

The entire batch is then heated to 115 ° C for 120 min, in order to isomerize the 2M3BN directly into 3PN. A sample is taken and the relationship determined 2M3BN / 3PN by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 3.3.

Example 5: (with butadiene separation) From a catalyst solution composed of 0.56% of Ni (0), 62.2% of 3PN and 37.24% of ligand 1, 2 mmol of Ni (0) are extracted, mixed with 705 mmol of BD, It is filled at 25 ° C in a glass autoclave and heated to 90 ° C. They are dosed now for 72 min. 411 mmol of HCN in THF, shake for another 60 min. at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The excess BD is now distilled at 100 mbar and 50 ° C and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 1.4.

The entire batch is then heated to 115 ° C for 120 min, in order to isomerize 2M3BN directly into 3PN. A sample is extracted and the relationship is determined 2M3BN / 3PN by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 13.2.

Example 6: (without butadiene separation) ligand 2 6 mmol of ligand 2 are mixed with 2 mmol of Ni (COD) 2 and 81 mmol of BD in THF, at 25 ° C they are autoclaved glass and heated up to 90 ° C. During 85 min. 407 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). In addition, the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 0.55.

The whole batch is then heated to 115 ° C for 120 min, in order to isomerize 2M3BN directly into 3PN A sample is extracted and the relationship is determined 2M3BN / 3PN by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 1.2.

Example 7: (with butadiene separation) 6 mmol of ligand 2 are mixed with 2 mmol of Ni (COD) 2 and 583 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. During 105 min. 411 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The excess BD is now distilled at 100 mbar and 50 ° C and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by CG area). The 2M3BN3PN ratio is 1 / 0.6. - then the whole batch is heated to 115 ° C for 120 min, in order to isomerize 2M3BN directly into 3PN. A sample is extracted and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 8.9.

Example 8: (without butadiene separation) ligand 3 6.3 mmol of ligand 3 are mixed with 2 mmol of Ni (COD) 2 and 581 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. During 85 min. 407 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The excess BD is now distilled at 100 mbar and 50 ° C and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN3PN ratio is%, 4.

The whole batch is then heated to 115 ° C for 120 min, in order to isomerize 2M3BN directly into 3PN A sample is extracted and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is%, 3.

Example 9: (with butadiene separation) 6 mmol of ligand 3 are mixed with 2 mmol of Ni (COD) 2 and 606 mmol of BD in THF, at 25 ° C are placed in a glass autoclave and heated to 90 ° C. For 76 min. 400 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The excess BD is now distilled at 100 mbar and 50 ° C and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN3PN ratio is 1 / 2.8.

The whole batch is then heated to 115 ° C for 120 min, in order to ispmerize 2M3BN directly into 3PN. A sample is extracted and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1/20.

Example 10: (without butadiene separation) ligand 4 2.6 mmol of ligand 4 are mixed with 0.84 mmol of Ni (COD) 2 and 612 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. For 80 min. 389 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). BD is distilled now at 100 mbar and 50 ° C surplus and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN3PN ratio is 1 / 1.3.

The entire batch is then heated to 115 ° C for 120 min, in order to isomerize 2M3BN directly into 3PN. A sample is extracted and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1 / 5,2.

Example 11: (with butadiene separation) 2.7 mmol of ligand 3 are mixed with 0.89 mmol of Ni (COD) 2 and 655 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. During 70 min. 414 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). The excess BD is now distilled at 100 mbar and 50 ° C and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN3PN ratio is 1.3 / 1.

The whole batch is then heated to 115 ° C for 65 min., In order to isomerize 2M3BN directly into 3PN A sample is extracted and the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by GC surface). The 2M3BN / 3PN ratio is 1/20.

Example: BD hydrocyanation in the presence of an S Example 12: 1.64 mmol of ligand 3 are mixed with 0.55 mol of Ni (COD) 2, 0.55 mmol of ZnCl2 and 380 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. For 100 min. 253 mmol of HCN in THF are now dosed, stirred for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). In addition, the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by weight of GC, int standard: ethylbenzene). The 2M3BN / 3PN ratio is 1 / 1.1. 0.2% MGN was formed.

Example 13: 1.72 mmol of ligand 4 are mixed with 0.56 mol of Ni (COD) 2, 0.57 mmol of ZnCl2 and 402 mmol of BD in THF, at 25 ° C they are placed in a glass autoclave and heated to 90 ° C. During 52 min. 259 mmol of HCN are now dosed in THF, stir for 60 min. more at 90 ° C and a sample is taken. The production of HCN is quantitative (volumetric analysis according to Vollhard). In addition, the 2M3BN / 3PN ratio is determined by gas chromatography (percentage by weight of GC, int standard: ethylbenzene). The 2M3BN / 3PN ratio is 1.5 / 1. MGN was not formed.

Claims (13)

1. Process for the continuous hydrocyanation of 1,3-butadiene in the presence of at least one catalyst, characterized in that catalysts are nickel (0) catalysts stabilized with phosphorus chelate ligands, 1,3-butadiene and hydrocyanic acid in a molar ratio from 1.6 up to 1.1 to 1.

2. Process according to claim 1, characterized in that the nickel (0) catalyst is saturated with phosphorus chelate ligands, wherein the phosphorus chelate ligands are selected from the group consisting of bidentate phosphites, phosphines, phosphonites, phosphinites and phosphinit phosphites

3. Process according to claim 1 or 2, characterized in that the continuous hydrocyanation is carried out additionally in the presence of at least one acid of Lewis.

4. Process according to one of claims 1 to 3, characterized by the following process steps: (a) continuous hydrocyanation of 1,3-butadiene in the presence of at least one nickel (0) catalyst with chelate ligands and optionally in the presence of at least one Lewis acid, where 1,3-butadiene and acid are used hydrocyanic in a molar ratio of 1.6 to 1.1 to 1 and a mixture 1 is obtained which contains 3-pentenenitrile and 2-methyl-3-butenonitrile; (c) Continuous isomerization of. 2-methyl-3-butenonitrile, which is contained in mixture 1, in at least one isomerization catalyst dissolved or dispersed in 3-pentenenitrile, resulting in a mixture 2.

5. Process according to claim 4, characterized in that the 3-pentenenitrile obtained in process step (c) is hydrogenated in the presence of at least one nickel (0) catalyst with phosphorus ligands.

6. Process according to claim 4 or 5, characterized in that the isomerization in the process step (c) is carried out by heating the mixture 1 between 80 and 125 ° C.

7. Process according to one of claims 4 to 6, characterized in that the continuous isomerization carried out in process step (c) is carried out in the presence of at least one 5 Lewis acid.

8. Process according to one of claims 4 to 7, characterized in that between process step (a) and process step (c) is 10 performs the following process step (b): (b) .distillative separation of 1,3-butadiene from mixture 1.

9. Procedure according to one of the 15 claims 4 to 8, characterized in that the isomerization catalyst used in process step (c) is the nickel (0) catalyst used in the process step (a) with chelate ligands.

10. Process according to claims 1 to 9, characterized in that the hydrocyanuration is carried out in the presence of additional monodentate phosphorus ligands, selected from the group consisting of phosphines, phosphites, phosphinites and phosphonites. , 25

11. Process according to claim 10, characterized in that a ligand of the formula II is used as an additional monodentate phosphorus ligand. PÍX ^ -R1) (X2R2 (X3R3) (II) where X1 / X2, X3 mean, the one independently of the other, oxygen or a simple bond, and R1, R2, R3 mean, each independently of the other, identical or different organic radicals, or their mixtures.

The method according to claims 10 and 11, characterized in that compounds of the formula Ha are used (o-tolyl-O-) w (m-tolyl-O-) x (p-tolyl-O-) and (phenyl-O-) ZP (Ha) where w, x, y and z represent a natural number and are worth the following conditions: w + x + y + z = 3 y, z 2.

13. Process according to claims 10 to 12, characterized in that the additional monodentate phosphorus ligand of the nickel complex (0) and the free additional monodentate phosphorus ligand is selected from tritolyl phosphite, as well as the phosphites of the formula Ilb where R1, R2 and R3 mean, each independently of the other, o-isopropyl-phenyl, m-tolyl and p-tolyl, R4 is phenyl; x is 1 or 2, e y, z, p mean, each independently of the other, 0, 1 or 2, being precise, that x + y + z + p = 3, and their mixtures.