Process and catalyst system for the trimerization of acetylene and acetylene compounds.

p0001It is known that one can cyclize acetylene and acetylene compounds to benzene and the corresponding benzene derivatives. After Reppe arises from propargyl alcohol in the presence of Ni (CO) ₂ [P (C₆H₅) ₃] ₂ as catalyst in nearly quantitative yield a mixture of 1,3,5 and 1,2,4-tris (hydroxymethyl) benzene. This reaction is so rough that they can be practically carried out only in high dilution and slow addition of Acetylenkomponente. Even then the product remains contaminated by difficult separable byproducts. Another disadvantage of the catalyst is that can be trimerized few acetylene excluding acetylene.

p0002In the DE-PS 11 59 951 are carbonylfreie phosphite or thiophosphite containing nickel (0) described complex compounds by the reaction of nickel (0) bis-acrylonitrile, nickel (0) bis-acrolein or nickel (0) -to-duroquinone be synthesized. These compounds can be achieved partly excellent yields under mild reaction conditions. Particularly good results are obtained with aryl phosphite ligands to the oxygen atom carrying bulky substituents in the o-position. The disadvantage of this method resides in that the nickel compounds employed ultimately from Ni (CO) ₄ must be prepared.

p0003In the patents DE-PS 20 46 200 and DE-PS 20 56 555 forthe trimerization of 3-methyl-1-in-3-ol are given the use of nickel carbonyl in combination with Triarylphospiten which also achieved excellent results in this case be when bulky substituents are present in the o-position.

p0004Under present security aspects methods are using nickel carbonyl for industrial use is no longer in question. There is therefore an interest in a process in which one can use an easily manageable, technically safe catalyst component.

p0005The resultant object is solved according to the claims.

p0006A carbonyl ligand-free nickel (0) compound is the tetrakis (triphenylphosphite) nickel. From this nickel complex is one part diegeringe air and temperature sensitivity, on the other hand, the inertness and the associated limited use in the nickel chemistry known.

p0007It has now been found, surprisingly, that it is possible acetylenic compounds in the presence of tetrakis (triphenylphosphite) nickel (0) trimerize catalytically if at least one Wider phosphite compound is present and the reaction is optionally in an inert solvent and at a temperature of 20 to 120 ° C, preferably 50 to 100 ° C, in particular 70 to 90 ° C, is performed.

p0008Suitable inert solvents such as. For example, hexane, n-octane, isooctane, cyclohexane, cyclooctane, benzene, toluene and xylene are aliphatic, aromatic and araliphatic hydrocarbons, are suitable.

p0009With this catalyst system, many different acetylene, which may be substituted in addition to the carbon-carbon triple bond in addition mitgesättigten or unsaturated groups trimerized. Of the suitable compounds which may be mentioned: methyl acetylene, phenylacetylene, 3-methyl-3-en-1-in, 4-methoxybut-3-en-1-in, propargyl, Propargylethylether, 3-methyl-1-in-3 ol, 3-methylpent-1-in-3-ol, but-2-yne-1,4-diol.

p0010The best results are achieved by combining tetrakis (triphenylphosphite) nickel (0) with such phosphite compounds, preferably phosphorous carrying bulky substituents in the o-position to the heteroatom. As phosphites also Thiophosphites suitable.

p0011Phosphites of this type are, for. Example, tris (2-isopropyl-5-methylphenyl) phosphite, tris (2,6-dimethylphenyl) phosphite, tris (2-tert-butyl-5-methylphenyl) phosphite, tris (2-sec .-butylphenyl) phosphite, tris (2-tert-butyl-4-methylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2-tert-butylphenyl) phosphite, tris (2-diphenylyl ) phosphite.

p0012, The reaction of the nickel (0) compound with the phosphites for the preparation of the catalyst preferably in an inert solvent and at a temperature of 20 ° C to 120 ° C, preferably 50 to 100 ° C, in particular from 70 to 90 ° C through by both components in a molar ratio of 1: 1 to 1: 5, preferably 1: 1.5 to 1: 2.5, preferably in an inert gas are mixed under stirring for some time.

p0013Suitable solvents are aliphatic and aromatic and araliphatic hydrocarbons, such as. For example, n-hexane, n-octane, isooctane, cyclohexane, cyclooctane, benzene, toluene and xylene.

p0014Method according to the invention is carried out by bringing the starting compound into contact with the catalyst. It is preferable to apply 1 to 10 weight percent catalyst, more preferably 5 to 8 weight percent, based on the starting material, to. The reaction is conducted at a temperature of 20 to 120 ° C, preferably from 50 to 100 ° C, in particular from 70 to 90 ° C, carried out preferably in a solvent which was used for the preparation of the catalyst. The preparation of the catalyst and the trimerization is preferably carried out in one stage.

p0015The procedure is generally carried out under atmospheric pressure, higher pressures are particularly employed when the reaction temperature is above the boiling point of acetylene and / or the selected solvent. The reaction can be carried out batchwise and continuously. The products obtained by the process are useful intermediates for the preparation of polyfunctional benzene derivatives.

example 1

p0016In a round bottom flask 0.5 g of tetrakis (triphenylphosphite) nickel (0), 0.3 g of tris (2-tert-butylphenyl) phosphite and 10 ml of 3-methylbut-1-in-3-ol in 10 ml of toluene and heated with stirring to 100 ° C. For working up the mixture is cooled to 5 hours at room temperature, filtered the crystallized solid, washed with toluene and ether and dried in a vacuum. According to the NMR spectrum, the product of 1,3,5-tris (alpha-hydroxyisopropyl) is benzene. The yield is 60% of theory.

example 2

p0017In the manner described in Example 1, 0.5 g of tetrakis (triphenylphosphite) nickel (0), 0.18 g of tris (2-sec-butylphenyl) phosphite and 10 ml of methylbutynol in 15 ml n-heptane at reaction temperatures of 90 ° C implemented. The yield is 60% of theory.

example 3

p00180.5 g of tetrakis (triphenylphosphite) nickel (0) and 0.18 g of tris (2-sec-butylphenyl) phosphite are heated in 15 ml of n-heptane at reflux temperature (98 ° C). 29 g Methylbutynol be dosed within one hour to this mixture. After 5 hours of reaction, allowed to cool and operates as in Example 1, on. The yield is 41% of theory.

example 4

p0019In a round bottom flask 0.5 g of tetrakis (triphenylphosphite) nickel (0), 0.18 g of tris (2-sec-butylphenyl) phosphite and 10 ml phenylacetylene heated with stirring to 100 ° C. For working up, distilled under reduced pressure from unreacted phenylacetylene and the residue is recrystallized from ethanol. The product consists of 1,3,5-triphenyl-. The yield is 40% of theory.

Comparative Example A

p0020If the reaction is, as described in Example 1, without the addition of tris (2-tert-butylphenyl) phosphite by, it can be after cooling no 1,3,5-tris (alpha-hydroxyisopropyl) isolate benzene.