GB2036011A - Cyano-substituted Aldehydes and Alcohols - Google Patents

Abstract

A process for the production of a cyano-substituted aldehyde and/or alcohol by reacting an alkenenitrile with carbon monoxide and hydrogen in the presence of a cobalt catalyst. The product may be hydrogenated in one step to the diamine e.g. 3- pentenenitrile may be converted in two stages to hexamethylene diamine.

Description

SPECIFICATION Cyano-substituted Aldehydes and Alcohols The present invention relates to cyanosubstituted aldehydes and/or alcohols.

In our British patent No. 1,497,046 we have described a process for the manufacture of cyanosubstituted aliphatic carboxylic esters in which an alkenenitrile having at least 3 carbon atoms in the alkene residue is reacted with carbon monoxide and an alcohol under pressure in the presence of a catalyst which is preferably a known carbonylation catalyst e.g. a transition metal.

The alkenenitriles which are singled out in British patent No. 1,497,046 as being particularly useful in the process therein described are those of formula CnH2n~,CN where n is 4 or 5 e.g. 3- pentenenitrile which, on carbonylation with methanol for example, gives methyl d- cyanovalerated said to be convertible to adiponitrile by reaction with ammonia in the presence of a dehydrating catalyst, the adiponitrile in turn being capable of hydrogenation to hexamethylene diamine which is an important polymer intermediate.

The process described in British patent No.

1,497,046 takes two stages to convert the cyano ester to hexamethylere diamine. We have now devised a process for the production from an alkenenitrile of a cyano-substituted product which may be converted in one step to hexamethylene diamine and under milder conditions than those required by the process of the British patent.

According to one aspect of the invention a cyano-substituted aldehyde and/or alcohol is produced by reacting an alkenenitrile having at least 3 carbon atoms in the alkene residue with carbon monoxide and hydrogen under pressure in the presence of a cobalt catalyst.

According to a further aspect of the invention the cyano-substituted aldehyde and/or alcohol is converted to the corresponding diamine by hydrogenation with molecular hydrogen in the presence of ammonia and a hydrogenation catalyst.

The aikenenitriles which are the starting materials for the process according to the invention include compounds of the formula CnH2n~,CN where n is an integer of 3 or more. In particular, compounds in which n is 3 to 10 especially 4 or 5 give valuable products when used in the process for example 3-butenenitrile, 2-methyl-3-butenenitrile, 4-pentenenitrile, 5- hexenenitrile and, in particular, 3-pentenenitrile.

The latter compound may be conveniently obtained by the hydrocyanation of butadiene e.g.

as described in our British patent No. 1,429,651.

The cobalt catalyst is preferably used in the process in the form of one of its compounds particularly as the carbonyl or carboxylate. The carboxylate may be aliphatic or aromatic in nature, e.g. cobalt benzoate or cobalt naphthenate or a cobalt salt of a C1 to C25 alkanoic acid such as cobalt acetate or cobalt stearate. The cobalt is present in the reaction in catalytic amounts, e.g. 1 to 2,000 preferably 50 to 500 parts per million. A biphyllic trivalent phosphorus-containing ligand may also be included in the reaction medium. The ligand may be a phosphite, phosphonite or phosphinite but is preferably a phosphine particularly a trialkylphosphine in which the alkyl groups each contain 1 to 6 carbon atoms. The presence of the ligand tends to produce a more linear cyanoaldehyde and/or cyano-alcohol than is produced in its absence.

The process is carried out at an elevated pressure which is suitably provided by the carbon monoxide and hydrogen. Preferably the pressure is 25 to 500 bars more preferably 50 to 300 bars.

The mole ratio of carbon monoxide to hydrogen is preferably 1:1 but may vary in the range 1:3 to 3:1.

The temperature under which the process is carried out suitably lies in the range 500 to 3000C particularly 1000 to 20012C.

The process may conveniently be carried out in the presence of a solvent which should be liquid under the reaction conditions and which should be chemically inert with respect to the reactants.

Thus, preferred solvents are hydrocarbon in nature e.g. saturated aliphatic hydrocarbons such as hexane or cyclohexane or aromatic hydrocarbons e.g. benzene, toluene or xylene.

Alternatively the solvent may be a ketone e.g.

acetone or an ether or ester.

The product of the process may be the aldehyde, alcohol or a mixture of the two. For subsequent conversion to the diamine it is preferred that the aldehyde level be as high as possible. The cyano-aldehyde or cyano-alcohol or mixture of the two may be reductively aminated to the corresponding diamine by means of molecular hydrogen and ammonia using a hydrogenation catalyst.

The reductive amination may be carried out under conditions conventional for this type of reaction. Thus the catalyst may be a copper or nickel catalyst e.g. "Copel" and the reaction may be carried out at elevated temperature and pressure e.g. 1000 to 6000C and 5 to 500 bar. A solvent may be used if desired, particularly one of the hydrocarbon solvents listed above.

The invention will now be described with reference to the following Examples: Example 1 3-pentenenitrile 8.4 9 (0.104 moles) in acetone (30 ml) was heated in an autoclave at 1 200C and at 200 bar pressure (CO:H2 ratio 1:1) for 3 hours at a cobalt concentration of 300 ppm.

Distillation of the product at 1 mm pressure gave 9.5 g of the cyano valeraldehyde bp 72-760C.

This consisted of a 1:1:1 mixture of the P, y and 8-cyanoaldehydes.

Example 2 3-pentenenitrile 21 g (0.26 mole) in toluene (20 ml, containing tri-n-butyl phosphine (0.54 g) was heated in an autoclave at 1 700C and 120 bar pressure (CO:H2 ratio 1:1) for 1 hour at a cobalt concentration of 1,500 ppm. Distillation at 1 mm pressure gave 2 g of the cyano valeraldehyde mixture.

Example 3 3-pentenenitrile 10 mls (0.10 mole) in toluene (30 mls) was heated in an autoclave at 1 700C and 250 bar working pressure for 2 hours at a cobalt concentration of 400 ppm. Analysis of the product showed a selectivity to S- cyanovaleraldehyde of 65% at 60% conversion.

Example 4 Product from the preceding Examples consisting of a mixture of cyanovaleraldehydes (5.2 g, 0.047 mole) which contained 60% of - cyanovaleraldehyde was placed in an autoclave with a solution of ammonia (8.4 g, 0.49 mole) in methanol (23 g) and Raney nickel catalyst (0.25 g). The autoclave was heated at 1000C for 2 hours under a hydrogen pressure of 140 atmospheres. Gas chromatographic analysis of the product showed a 25% conversion of the - cyanovaleraldehyde to hexamethylene diamine.

Claims (17)

Claims

1. A process for the production of a cyanosubstituted aldehyde and/or alcohol in which an alkenenitrile having at least 3 carbon atoms in the alkene residue is reacted with carbon monoxide and hydrogen under pressure in the presence of a cobalt catalyt.

2. A process according to Claim 1 in which the alkene has the formula CnH2n~,CN where n is an integer between 3 and 10.

3. A process according to Claim 2 in which the alkenenitrile is 3-pentenenitrile.

4. A process according to any one of the preceding Claims in which the cobalt catalyst is cobalt carbonyl or cobalt carboxylate.

5. A process according to any one of the preceding Claims in which the cobalt is present in an amount of 1 to 2000 ppm of the reaction medium.

6. A process according to any one of the preceding Claims in which the alkene nitrile is reacted in a medium containing a biphyllic trivalent phosphorus-containing ligand.

7. A process according to Claim 6 in which the ligand is a trialkylphosphine in which the alkyl groups each contain 1 to 6 carbon atoms.

8. A process according to any one of the preceding Claims in which the pressure is 25 to 500 bars.

9. A process according to any one of the preceding Claims in which the mole ratios of carbon monoxide to hydrogen lies between 1:3 and 3:1.

10. A process according to any one of the preceding Claims in which the temperature lies in the range 500 to 3000C.

11. A process according to any one of the preceding Claims which is carried out in a hydrocarbon, ketone, ether or ester solvent.

12. A process according to Claim 1 in which the cyano-substituted aldehyde and/or alcohol is converted to the corresponding diamine by hydrogenation with molecular hydrogen in the presence of ammonia and a hydrogenation catalyst.

13. A process according to Claim 12 in which the hydrogenation catalyst is a copper or nickel catalyst.

14. A process according to Claim 12 or Claim 13 in which the temperature of the hydrogenation is 1000 to 6000C.

1 5. A process according to any one of Claims 12 to 14 in which the pressure in the hydrogenation is 5 to 500 bar.

16. A process for the production of a cyanosubstituted aldehyde and/or alcohol substantially as described in any one of Examples 1 to 3.

1 7. A process for the production of a diamine substantially as described in Example 4.

1 8. Cyano-substituted aldehydes and/or alcohols whenever produced by a process according to any one of Claims 1 to 11 and 16.

1 9. Diamines whenever produced by a process according to any one of Claims 12 to 15 and

17.