CA1082224A

CA1082224A - Organic nitriles

Info

Publication number: CA1082224A
Application number: CA262,363A
Authority: CA
Inventors: Dhafir Y. Waddan; Robert J. Benzie
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1975-10-01
Filing date: 1976-09-30
Publication date: 1980-07-22
Also published as: ES452037A1; IT1075030B; JPS5936905B2; NL7610820A; DE2642449A1; DE2642449C3; JPS5248624A; DE2642449B2; FR2326412B1; FR2326412A1

Abstract

ABSTRACT OF THE DISCLOSURE

Process for the manufacture of dicyanobutene which comprises reacting butadiene with hydrogen cyanide and oxygen or an oxygen-containing gas in the presence of a catalyst comprising copper ions and halide ions and of a solvent for the catalyst.

Description

H.28239 /287Lr~
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THIS INVENTION relates to organic nitriles, more speci~ically to dicyanobutene and to a method for its manufacture from butadiene.
It has already been proposed to manufacture dicy-anobu-tene from butadiene by a two-s-tage process in which butadiene is chlorinated to give dichlorobutene, and -the dichlorobutene is then reacted with hydrogen cyanide or an alkali metal cyanide to give dicyanobu-tene. Apart from the fact that two stages are involved, the me-thod involves the introduc-tion of chlorine and its subsequent removal. It has also been proposed to react butadiene with hydrogen cyanide in presence of a catalyst, for example a zerovalent nickel catalyst, as described, for example, in British P~tent Specification No. 1,104,140, but commercially known methods introduce only one cyano group to give a mixture of pentene-nitriles and me-thyl-butenenitriles. The pentenenitriles may subsequently be reacted with ~urther hydrogen cyanide in a separate stage to give adiponitrile, but the latter compound cannot be obtained by this method from butadiene in a single stage in significant yield.
We have now found a method by which two cyano groups may be introduced into the molecule of butadiene in a single stage to give dicyanobutene.
Our invention provides a process for the manufacture of dicyanobutene which comprises reacting butadiene with hydrogen cyanide an(i oxygen or an oxygen-containing gas in the presence of a catalyst comprising copper ions and ,. ~

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H,2~239 /28748 :1~8~Z2~

halide ions and of a solvent for -the ca-talyst.
The copper ions in the catalyst used in the process of our invention may be added in the cuprous or cupric form. Under the influence of the oxygen used in the process cuprous ions tend to be oxidised to cupric, whereas the hydrocyanation reaction tends to cause the cupric ions to be reduced to cuprous.
The copper may be added to the reaction mixture as a halide, for example as cuprous or cupric chloride, bromide or iodide (or as any mixture thereof) since this will ensure the presence of halide in addition to copper, but this is not essential. Other copper salts may be used, especially the salts o~ organic acidsj more especially the sal-ts of aliphatic carboxylic acids and particularly the salts of alkane carboxylic acids having from 2 to 6 carbon atoms. As examples of such copper salts there may be mentioned copper formate, acetate, propionate, bu-tyrate, lactate, l~;lycollate, acetylacetonate, naphthenate, stearate and benzoate. Moreover, other sources of halide ion may be used for example alkali metal and ammonium chloride, bromide and iodide as well as hydrogen chloride, bromide ~nd iodi~le and chlorine, bromine and iodine themselves. ~ur-ther, organic chlorine, bromine and iodine compounds may be used as the halide source, for example tetrabromoethane, chloracetic acid, bromoacetic acid, acetylbromide, dichlorobutene and dibromobutene, as well as hydrochlorides, hydrobromides and hydriodides "

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of organic bases and quaternary amm~nium bromides and iodides. It is advantageous also for there -to be present an alkali metal salt, for example a sodium, potassium or especially a lithium salt, or an 5 alkaline earth metal salt, for example a beryllium, -magnesium, calcium or barium salt. Such a salt is preferably a chloride, bromide or iodide, but may be, for example, an organic acid salt, especially a salt with one of the organic acids specified above as forming suitable copper salts. As examples of such salts there may be mentioned, lithium chloride, lithium bromide, lithium iodide, lithium acetate, lithium propionate, sodium bromide, sodium iodide, sodium acetate, potassium bromide, potassium iodide, potassillm acetate and magnesium bromide.
Preferably the halide ion in the catalyst ~ -consists of a mixture of chloride and/or bromide ion with iodide ion, since this gives a more active catalyst.
Mixtures of bromide with iodide ion are particularly suitable. The uptake of oxygen may be assisted by the presence of oxygen carriers, for example, manganese compounds, e.g. manganese gluconate.
As solvents for the catalyst there may be used a wide variety of compounds. The basic reciuirements are that -the catalys-t components shall dissolve to a greater or less extent in -the solvent and that the solvent shall not interfere with the reaction and shall not itself be . . .

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extensively changed by the reaction. Thus olefinically unsaturated compounds which react with hydrogen cyanide under the reaction conditions are unsuitable, as are solvents, for example mercaptans, which would be oxidised by -the oxygen-containing gas under the reaction conditions. The solvent should preferably be liquid at the reaction temperature and pressure. However, compounds which are normally solid under the reaction conditions may be used dissolved in another solvent.
Water is a suitable solvent as are many organic compounds. Particularly suitable classes of organic compounds include nitriles, alcohols, phenols, ethers, acids, ketones and amides. Suitable nitriles include aliphatic, cycloaliphatic, araliphatic and aromatic 15 nitriles, More especially they include alkyl nitriles and alkylene dinitriles, particularly those having from 1 to 6 carbon atoms in the alkyl or alkylene residue, for example acetonitrile, propionitrile, butyronitrile, hexanonitrile, glutarodinitri~e adiponitrile, dicyano-2~ butene and succindinitrile, alkenyl nitriles, for exampleacrylonitrile, methacrylonitrile, butenenitriles, methyl butenenitriles and pentenenitriles, higher polynitriles, for example tetracyanoethylene, cycloalkyl nitriles, for example cyclohexyl cyanide, aralkyl nitriles, for 25 example ben%yl cyanide and ~ xylylene dinitrile and aryl nitriles, for example benzonitriles, tolunitriles, phthalodinitrile and terephthalodinitrile. Particularly .', ~; ' - 5 - `

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~ 2~239/28748 2~

suitable nitriles include acetonitrile, propioni-trile and adiponitrile.
Suitable alcohols include aliphatic, cycloaliph-atic and araliphatic alcohols. More especially they include alkanols, particularly those having from 1 to 6 carbon atoms, for example methanol, ethanol, n-propanol, isopropanol, butanols, pentanols and hexanols, alkandiols, particularly those having from l to 6 carbon atoms, for example ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-l,L~-diol, pen-tane-diols and hexanediols, alkane-polyols, for example glycerol and trimethylolpropane, aralkanols, for example benzyl alcohol and 2-phenylethanol, and cycloalkanols, for example cyclopentanol, methylcycl-15 opentanols, cyclohexanol and methylcyclohexanols. -Par-ticularly suitable alcohols include ethanol and isopropanol.
Suitable phenols include phenol i-tself, alkyl-phenols, for example cresols, ethylphenols and xylenols, and halogenophenols, especially chlorophenols and di- and tri-chlorophenols. m-Cresol is a particul-arly suitable phenol.
Suitable e-thers include aliph~tic ethe~ aral-iphatic ethers, aromatic ethers and cyclic ethers.
More especially they include dialkyl ethers, for example di-isopropyl ether and methyl butyl ether, bis-ethers and polyethers for example 1,2-dimethoxy-ethane, 1,2-dimethyoxypropane and diethyleneglycol .

~3 H. 28~9/287L~8 ~82:Z~4 dimethyl ether (diglyme ), cyclic ethers, for example tetrahydrofuran, tetrahydropyran, dioxan, diphenylene oxide and crown e-ther (6, 7, 9, 10, 17, 18, 20, 21 -octahydrodibenzo (b, k) (1, 4, 7, 10, 13, 16) ~
hexaoxacyclooctadecene), alkyl aryl ethers, for example anisole and phenetole, diaralkyl ethers, for example dibenzyl ether, and diaryl ethers for example diphenyl oxide. Dimethyoxyethane, diglyme and tetra-hydrofuran are p(srticularly suitable ethers.
Suitable organic acids are especially the carboxylic acids. Suitable carboxylic acids include aliphatic, cycloaliphatic, araliphatic and aromatic carboxylic acids. More especially they include alkane carboxylic acids, particularly those having from 2 to 6 carbon atoms in the alkane residue, for example acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid or caproic acid, cycloalkane carboxylic acids, for example cyclohexane carboxylic acid and cyclohexylacetic acid, aralkyl carboxylic acids, for example phenylacetic acid, aryl carboxylic acids, for example benzoic acid, toluic acids and anisic acids, and napthenic flcids. Acetic acid is particularly suitable.
Suitable ketones include aliphatic, cycloaliphatic, araliphatic, aroma-tic and cyclic ketones. More especially they include dialkyl ketones, particularly ~ -those having from 1 to 6 carbon atoms in the alkyl residues, for example acetone, methyl ethyl ketone H.28239 ~28748 ~3222~

and methyl isobutyl ketone, diketones, for exarnple acetylacetone, cyclic ketones, for example cyclo-pentanone, methylcyclopen-tanone, cyclohexanone and methylcyclohexanone, alkyl aryl ketones, for example acetophenone, and diaryl ketones, for example benzophenone. Acetone and ace-tylacetone are particularly suitable ketones. ~-Suitable amides include in particular aliphatic carboxylic amides and their N-substituted derivatives.
More especially they include alkane carboxylic amides, particularly those having from 1 to 4 carbon atoms, and their N-alkyl and N,N-dialkyl derivatives -especially those having from 1 to 4 carbon atoms in the alkyl residues, for example formamide, N-methyl-formamide, N,N-dimethylformamide, acetamide, N,N-dim-ethylacetamide and propionamide. They also include cyclic amides for example N-methyl-2-pyrrolidone.
Dime-thyl~ormamide is a particularly suitable amide. -Suitable solvents also include compounds which contain two or more of the functional groups whichcharacterise, respectively, the said nitriles, alcohols, phenols, ethers, acids, ke-tones and amides, or contain one or more of the said functional groups in combination with some other group. Such compounds include, for example, ether-alcohols, for example ethylene glycol monomethyl and monoethyl ether, nitrile-acids, for example cyanoacetic acid and ~-cyanovaleric acid, .'. , , ' ~ .:
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- H.282 39! 287L

~ 4 halogeno-acids, for example chloroace-tic acid, dichlor-oacetic acid and trichloroacetic acid, and nitrile-esters, for example ethyl cyanoacetate.
Other suitable solvents include es-ters, especially the esters formed from the alcohols and acids already described as suitable solvents. Particularly suitable esters are the lower alkylesters (e.g. where lower alkyl has from 1 to 4 Carbon atoms) of aliphatic mono-or di-carboxylic acids especially -those having from 1 to 6 carbon atoms, for example methyl acetate, ethyl ~cetate, iso-propyl ~ceta-te, ethyl propionate, methyl butyra-te, dimethyl succinate, dimethyl glu-tarate and diethyl adipate.
Other suitable solvents include hyurocarbons and halogenated hydrocarbons. Such solvents include both aliphatic, cycloaliphatic and aromatic hydrocarbons, and their halogenated derivatives, for example hexane, cyclohexane, benzene, toluene, xylene, chloroform, carbon tetrachloride, trichloroethylene, tetrachlorethane, dibromoethane, chlorobenzene, bromobenzene, dichlorobenzene trichlorobenzene and diphenyl. ;
Other suitable solvents include thioethers, that is sulphides,including cyclic sulphides, for example dimethyl sulphide, diethyl sulphide, dipropyl sulphide, dibu-tyl sulphide, diamyl sulphide, dihexyl sulphide, methyl ethyl sulphide, thiophen, tetrahydrothiophen, pentamethylene sulphide, dicyclohexyl sulphide, dibenzyl sulphide, diphenyl sulphide, ditolyl sulphide and thiodiglycol.

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H.28239/28748 Other suitable solven-ts include sulphoxides and sulphones, especially dialkyl sulphoxides and sulphones, particularly where the alkyl group has from 1 to 6 carbon atoms, and cyclic sulphoxides and sulphones, for example dimethyl sulphoxide, diethyl sulphoxide, diethyl sulphone, dime-thyl sulphone, tetra-methylene sulphoxide, tetrame-thylene sulphone (sulpholane ) and pentamethylene sulphoxide and pentamethylene sulphone.
The solvents may be used singly or in admixture with each other in any convenient proportions. More-over the solvents may be used in admixture with other organic compounds which are not in themselves solvents for the catalyst.
The oxygen may be used as such or in admixture with non-re~ctive gases such as nitrogen. Air is a particularly sui-table oxygen-containing gas, but mixtures of oxygen and nitrogen with a higher or lower proportion of oxygen than that of the air may also be 20 used.
The reaction is conveniently carried out at temperatures within the range 10 to 150C, preferably from 35 to 110C. The reaction may be carried ou-t at atmospheric pressure or at pressures above or below that ; -25 of the atmosphere. The process may advantageouslybe operated under pressure, and pressures may, for example, be up to about 50 bar. Pressures in the range 2 to 10 bar~
absolute are very suitable.

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The reaction may conveniently be carried out by passing butadiene and hydrogen cyanide in vapour form together with oxygen or an oxygen-containing gas through a liquid comprising the catalyst and solvent under the selected tempera-t;ure and pressure conditions.
Alternatively, the butadiene and hydrogen cyanide may be kept in the liquid phase under pressure with the catalyst and solvent, and the oxygen or oxygen-containing gas passed through. It is not essential, however, for ~;
the oxygen or oxygen-containing gas to be con-tacted simultaneously with the catalyst and solvent. It is possible, for example, to pass butadiene and hydrogen cyanide on the one hand and oxygen-containing gas on the ;~
other hand alternately through the liquid comprising the ; 15 catalyst and solvent. Passage of oxygen or oxygen-cont- ;
aining gas in these circumstances leads to a change in the colour of the liquid to dark brown.
The butadiene used in the process of our invention may contain other constituents. For example the bu-tadiene may be admixed with other C4 hydrocarbons for example butenes and butane. Instead of using bu-tadiene itself, a crude CL~ stream from a cracker containing possibly less than 50% of butadiene may be used as the feed in our process to produce dicyanobutene.
Water is formed in the process of our invention, and it may be desirable, for example when using organic solvents, to remove the water from the reaction system.
The water is usually taken up into the reactant gas - 11 - .

~8239 /28748 Z~9~

stream and is preferably condensed ou-t from the effluent gas stream at least in par-t, prior to any recycle.
In carrying out the process of our invention the molar ratio of hydrogen cyanide -to butadiene may vary widely, for example over the range 1:10 to 10:1, but preferably over the range 1:2 to 4:1. The oxygen is preferably used in molar excess in relation to whichever of the hydrogen cyanide and butadiene is 10 used in the smaller molar amount.
The catalyst is used in catalytic amount.
The amoun-t of copper ion may vary, for example, from 0.001 mole to 0.2 mole per mole of butadiene, although higher proportions are not excluded. The amount of ;
15 halide ion in total may vary, for example, wi-thin the same molar range, although we prefer that there is at least one mole of halide ion per mole of copper ion.
Where, as we prefer, the halide ions consists of a mixture of chloride and/or bromide ion with iodide 20 ion the relative proportions of iodide to chloride and/or bromide may vary within wide limits, for example -the iodide may vary from 0.1% to 90% of the combined chloride, bromide and iodide on a molar basis, but we prefer the iodide proportion to be 25 between 1% and 10%. The amount of solvent used may vary widely. There should preferably be at least one mole of solvent per mole of copper ion, and amounts between 5 moles and 100 moles are convenient. When ' .
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H ~8239 '/28748 an alkali metal or alk;~line earth metal compound is present it may be used in amounts up to several times the molar amount of copper, for example in amounts of from 0.5 to 15 moles per mole of copper.
The dicyanobutene obtained as the product of our process is normally present in the liquid reaction mixture and may be separated therefrom by conventional methods, for example by fractional distillation under :, reduced pressure, by extraction with solvents, or by a combination of such methods.
The process of our invention is particularly -adapted to continuous operation. I-t may be convenient to take the reaction to only partial completion, to separate at least some of the product and to recycle unchanged material. For this reason times of contact with the catalyst may vary widely. Such times may vary from a few minutes, for example 5 minutes, up to many hours, for example 50 hours.
The dicyanobutene product of our process is principally 1,4-dicyanobutene. This is a valuable intermediate, since it may, by hydrogenation of the double bond, be converted to adiponitrile which itself, on ;~
hydrogenation of the nitrile groups, give hexamethylene diamine, an intermediate useful in the manufac-ture of polymers, for example polyurethanes and especially polyamides, in particular polyamides made by polycond-ensation with dicarboxylic acids, for example with adipic acid to give polyhexamethylene adipamide (nylon 6.6) ~

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H~ 2823~/287L~8 useful for the manufacture of mouldings and for melt-spinning into synthetic fibres.
The invention is illustrated but not limited by the following Examples.
ExamE~
Into a solution of 3g cupric bromide and 0.75g li-thium bromide in 30g propionitrile maintained at 50C
there was passed butadiene at a rate of 2.5 l/hour into which had been evaporated liquid hydrogen cyanide at a 10 rate of 4 ml/hour. After 1 hour the passage of the butadiene/hydrogen cyanide mixture was stopped and oxygen was passed through the solution at a rate of

3.5 l/hour for 1 hour when the mixture had become dark brown. The cycle was then repeated. After a total 15 reaction time of 46 hours the reaction mixture was found to contain 2.22g of 1,4-dicyanobutene with no significant amounts of other unsaturated nitriles. The product was isolated by evaporation of the solvent and extraction of the residue with hot toluene.
Example 2 Example 1 was repeated except that a solution of 3g of cupric bromide in 30g of propionitrile was used as the catalyst solution. After 46 hours the reaction mixture was found to contain 1.26g of 1,4-dicyanobutene, -5 and after 160 hours 2.56g of 1,4-dicyanobutene.
Example 3 Butadiene at a rate of 6000 parts by volume per hour and oxygen at a rate of 6000 parts by volume per _ 14 _ hour were passed together through liquid hydrogen cyanide, which was thereby evaporated into the gas stream, and the resulting gas stream was passed through a mixture of 20 parts of cupric acetate and 42 parts of lithium bromide in 200 parts by volume of glacial acetic acid held at 90 -to 100C for a period of 9 hours, during which 44 parts by volume of liquid -hydrogen cyanide were evaporated into the gas ~tream.
The reaction mixture was diluted with water, extracted 10 with toluene, and the toluene evaporated from the extract. The residue consisted of 9.8 parts, 5% of ;~ ~;
which was 1,4-dicyanobutene-2 and 91% partly converted i ma-terial capable of further conversion to dicyanobutene. :
Example.s 4 - 7 For operation at atmospheric pressure the ;
reactor consisted of a heated, efficiently stirred vessel with a reflux condenser cooled to -6C. The initial charge contained:

propionitrile 77 parts by weight cupric bromide 8 parts by weight lithium bromide 2 parts by weight and iodine compounds as shown in Table 1 and was maintained at 50C.
The reactants butadiene 7 parts by wt. per hr.
hydrogen cyanide 6 parts by wt. per hr.
oxygen 8 parts by wt. per hr.

were fed -to the re~ctor. The excess gas can be recovered for recycle.
.

;":'''' - . ~ . . -H.28239/28748 When steady reactlon conditions had been achieved trans-l,L~dicyanobutene-2 was formed at the rates :
indicated in Table 1~ which rates were higher when iodine compounds were present than when they were absent. Moreover, the rates of formation of by-product cyanogen, also indicated in Table 1, were less when :
iodine compounds were present.

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28239~/28748 Example 8 To a solution of 4 parts by weight of cupric bromide, 2 parts of cuprous iodide and l part o~ thium bromide in 40 parts of propibnitrile held a-t 50C in a hot 5 water jacketed tubular reac-tor at atmospheric pressure was added a vapour phase mixture of hydrogen cyanide (1.15 parts by weight per hour), bu-tadiene (5.8 parts/
hour) and oxygen (3.4 parts/hour) via a gas bubbler.
After 78 hours, passage of gas was stopped and lOthe liquid reaction mix-ture was evaporated to dryness and the residue extracted with toluene from which 15.8 parts of trans-1,4-dicyanobutene-2 crystallised out on cooling to 0C, a yield of 5.25 moles per mole of copper present in the reaction mixture.
Example_9 The mixture prbpionitrile16 parts by weight cupric bromide 4 parts by weight lithium bromide l parts by weigh-t sodium iodide0.5 parts by weight butadiene6.2 parts by weight hydrogen cyanide 6.9 parts by weight was charged to a suitable pressure vessel and the pressure adjusted to L~. 5 bar absolute with air. After heating and maintaining the temperature at ~0C for l hour the reactor was cooled and the excess gas vented.

From the product 0.74 parts by weight of trans-1,4-dicyanobutene-2 was obtained equivalent to a rate of 0.174 mol/litre/hour based on the volume of reaction mixture.

H28239`/28748 2fl~

Example 10 Example 9 was repeated except that pure oxygen -~
was used instead of air. 2.04 parts by weight of trans-1,4-dicyanobutene-2 were obtained equivalent to a production rate of 0.480 mol/litre/hour based on the volume of reaction mixture.
Example 11 A mixture consisting of:

propionitrile 20 ml cuprous bromide 2 g cuprous iodide 1 g lithium bromide 1.5 g butadiene 10 ml hydrogen cyanide 15 ml cyanoacetic acid 1 g acetone 1 ml triphenylphosphine 0.1 g was stirred in a pressure vessel and charged with oxygen at 4.5 bar absolute then heated at 60C for 5.5 hr.
After releasing pressure the contents were analysed by G.L.C.(gas/liquid chromatography) and found to contain 11.84 g trans-l J 4-dicyanobutene-2.
Exampl~s12 - 16 Reaction mixtures containing in each case propioni-trile 20 ml.
cupric bromide 2 g.
cuprous iodide 1 g.
lithium bromide 0.5 g.
oxygen 4.5 bar absolute and the constituents shown in Table 2 were reacted at the temperatures for the times shown in Table 2. The -production of dicyanobutene shown in the Table is up to : - :

H.2g23g/28748 Z~

6 mols/mol copper for Examples 12 to 14 and approxim-a-tely 9 mols!mol copper for Examples 15 and 16.

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- H.28239/28748 2Z;~4 Example 17 A mixture consisting of:

propionitrile 18 ml ~
crown ether 6 ml : -cuprous bromide 2 g cuprous iodide 1 g lithium bromide 0.5 g butadiene 6 ml hydrogen cyanide10 ml was stirred in a pressure vessel and charged with oxygen at 4.5 bar absolute, then heated at 50C for ~;

4 hours, The product contained 6.8 g. of trans-1,4-dicyanobutene-2.
Example 18 15This example shows the use of a crude C4 s-tream from a cracker (containing 41.7% of butadiene) ` :
A mixture consisting of:

propionitrile 20 ml cuprous bromide 2 g cuprous iodide 1 g lithium bromide 0.5 g A C4 stream containing 41.7% of butadiene10 ml hydrogen cyanide10 ml was stirred in a pressure vessel and charged with oxygen at 4.5 bar absolute then heated at 50C for 15 hours. The product contained 3~44 g of trans-1,4-dicyanobutene 2.
Example 19 The effect of various solvents was examined by charging the following mixture to a pressure vessel ,.' , ' .. ' .

~-28239/28748 , :
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equipped wi-th a stirrer.

Solvent 20 parts by vol.
Cupric bromide 4 par-ts by weight Lithium bromicle 0.5 parts by weight sodium iodide 0.5 parts by weight Butadiene 10 parts by volume Hydrogen cyanide 10 parts by volume :
Oxygen (4.5 bar absolute equivalent to) .045 parts by weight 10 The reactor and contents were heated to 50C and this temperature maintained for 2 hours before cooling and venting excess gas. The residue was dissolved in solven-t and the amount of trans-1,4-dicyanobutene-2 in parts by weight was de-termined by G.~.C. The 15 results are summarised in the Table. _ _ ``,- .

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', ;, ' , H.28239/28748 r Solven-t Trans-1,4-dicyano-, _ _ butene-2 Water 0.68 Methanol 0.73 Ethanol 2.17 isopropanol 3.20 t-butanol .95 2 Phenylethanol .22 Ethylene glycol .23 Propane-1,2-diol .23 m-cresol 6.52 Tetrahydrofuran 2.42 Tetrahydropyran 1.16 Dioxan .56 1,2-Dimethoxyethane 3.91 Diglyme 2.54 Anisole .45 Acetic acid 1.55 Naphthenic acid .07 Methyl acetate .97 Diethyl adipate .41 Acetone 3.89 Cyclohexanone .17 Acetophenone 1.61 Acetylacetone 3.39 Ethyl cyanoacetate 1.17 N-Methylformamide 1.79 Dimethyl fprmamide 2.21 N-Methyl-2-pyrrolidone .43 n-hexane .17 Toluene .93 Brombenzene .52 Dichloromethane 1.03 Tetrachlorethane .90 ._ _ 24 -H,28239/28748 h~Z~

E,xample 20 :.
Example 19 was repeated, except that the reaction mixture was heated for 5 hours 9 using .
the following compounds as solvent and the quantity of trans-1,4 dicyanobu-tene-2 indicated (in parts by weight) was obtained. ~ .
.

. _ _.
Solvent Trans-1,4-dicyano-butene-2 ..
_ _ _ _ Benzonitrile 4.11 :
10 Adiponi-trile 6.24 ~:
Sulpholane - 5.02 :~
.
~ ç~_2 A gas stream consisting of butadiene at a -~
rate of 3 l/hr and oxygen at a rate of 6 l/hr and :;.
15 into which liquid hydrogen cyanide at a rate of --:: 8 ml/hr was fed was passed through a mix-ture of;

Benzonitrile 100 ml .
Cupric bromide 7.9 g -Lithium bromide 2 g 20 at 50C stirred at atmospheric pressure for 11 hours. Trans-1,4-dicyanobutene-2 was formed at a rate of 10.7 millimoles per li-tre of reaction mixture per hour. :~
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Claims

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A process for the manufacture of dicyano-butene which comprises reacting butadiene with hydrogen cyanide and oxygen or an oxygen-containing gas in the presence of a catalyst comprising copper ions and halide ions and of a solvent for the catalyst.

2. A process as claimed in Claim 1 in which the copper is added to the reaction mixture as a cuprous or cupric halide.

3. A process as claimed in Claim 1 in which the copper is added to the reaction mixture as a copper salt of an organic acid.

4. A process as claimed in Claim 1 in which an alkali metal or ammonium halide, a hydrogen halide, a halogen or an organic halogen compound is included in the reaction mixture to yield halide ion.

5. A process as claimed in Claim 1 in which the halide is chloride, bromide or iodide,

6. A process as claimed in Claim 1 in which the halide ion is a mixture of chloride and/or bromide ion with iodide ion.

7. A process as claimed in Claim 1 in which an alkali metal or alkaline earth metal salt is included in the reaction mixture.

8. A process as claimed in Claim 7 in which the metal salt is a lithium salt.

9. A process as claimed in Claim 1 in which the solvent is an organic solvent.

10. A process as claimed in Claim 9 in which the organic solvent is a nitrile.

11. A process as claimed in Claim 9 in which the organic solvent is an acid.

12. A process as claimed in Claim 9 in which the organic solvent is an alcohol, a phenol, an ether, a ketone or an amide.

13. A process as claimed in Claim 10 in which the organic solvent is an alkyl nitrile or alkylene dinitrile having from 1 to 6 carbon atoms in the alkyl or alkylene residue.

14. A process as claimed in Claim 13 in which the organic solvent in acetonitrile, propionitrile or adiponitrile.

15. A process as claimed in Claim 12 in which the organic solvent is an alkanol having from 1 to 6 carbon atoms.

16. A process as claimed in Claim 12 in which the organic solvent is m-cresol.

17. A process as claimed in Claim 11 in which the organic solvent is an alkane carboxylic acid having from 2 to 6 carbon atoms.

18. A process as claimed in Claim 17 in which the organic solvent is acetic acid.

19. A process as claimed in Claim 12 in which the organic solvent is a dialkyl ketone having from 1 to 6 carbon atoms in the alkyl residue or acetylacetone.

20. A process as claimed in Claim 12 in which the organic solvent is an alkane carboxylic amide having from 1 to 4 carbon atoms or an N-alkyl or N,N-dialkyl derivative thereof having from 1 to 4 carbon atoms in the alkyl residues.

21. A process as claimed in Claim 9 in which the organic solvent is an ester, a thioether, a sulphoxide or sulphone, or a hydrocarbon or halogenated hydrocarbon,

22. A process as claimed in Claim 1 in which the solvent is water.

23. A process as claimed in Claim l in which the oxygen-containing gas is air.

24. A process as claimed in Claim 1 in which the butadiene is introduced into the reaction mixture as a crude C4 stream containing butadiene.

25, A process as claimed in Claim 1 carried out at a temperature within the range 10° to 150°C.

26. A process as claimed in Claim 25 carried out at a temperature within the range 35° to 110°C.

27. A process as claimed in Claim 1 carried out at above atmospheric pressure.

28. A process as claimed in Claim 1 effected by passing butadiene and hydrogen cyanide in vapour form together with oxygen or an oxygen-containing gas through a liquid comprising the catalyst and solvent.

29. A process as claimed in Claim 6 in which the amount of iodide is from 1% to 10% of the combined chloride, bromide and iodide on a molar basis.