US3489789A - Process for the reductive dimerization of alpha,beta-olefinicallyunsaturated nitriles or esters - Google Patents

Process for the reductive dimerization of alpha,beta-olefinicallyunsaturated nitriles or esters Download PDF

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US3489789A
US3489789A US446430A US3489789DA US3489789A US 3489789 A US3489789 A US 3489789A US 446430 A US446430 A US 446430A US 3489789D A US3489789D A US 3489789DA US 3489789 A US3489789 A US 3489789A
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acrylonitrile
water
reaction
amalgam
adiponitrile
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Robert Alfred Dewar
Volker Elmar Maier
Margaret Anthea Riddolls
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Orica Ltd
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ICI Australia Ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/34—Esters of acyclic saturated polycarboxylic acids having an esterified carboxyl group bound to an acyclic carbon atom
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/34—Esters of acyclic saturated polycarboxylic acids having an esterified carboxyl group bound to an acyclic carbon atom
    • C07C69/44—Adipic acid esters

Definitions

  • This invention relates to a process for the manufacture of dicarboxylates, dinitriles and dicarboxamides in particular it relates to the manufacture of dinitriles and especially to the manufacture of adiponitrile from acrylonitrile.
  • the hydrodimerisation of acrylonitrile to adiponitrile according to the schematic equation has been disclosed by Knunyants and Vyazankin (Bull. Acad. Science U.S.S.R., 1957, pp. 238-240 who used as the reducing agent an amalgam of mercury and an alkali metal and strong hydrochloric acid as the medium containing the acrylonitrile in dilute solution. With this system adiponitrile was formed, but a considerable part of the acrylonitrile was converted to propionitrile and this has made the process uneconomic.
  • propionitrile can be depressed if a process of actual electrochemical reduction is employed which is characterised in that an electric current is passed from a separate anode through a solution of acrylonitrile in contact with a cathode having a hydrogen overvoltage greater than copper under specified conditions of hydrogen ion concentration and at concentrations of acrylonitrile in excess of 10%. It is advantageous to use in the specified direct electrolytic process, certain aliphatic and heterocyclic amine salts, quaternary ammonium salts and other salts. This is in clear contradistinction to the indirect methods as preparing sodium amalgam by electrochemical reduction of sodium salts followed by mere contacting of a solution of the olefin with the sodium amalgam.
  • the invention is especially useful for acrylonitrile and alkyl substituted acrylonitriles (as hereinafter defined).
  • the olefinic compounds are monoolefins.
  • salts capable of forming alkylated cations in aqueous media we mean salts forming e.g. ammonium, phosphonium or sulphonium cations such as tetraalkylammonium salts, tetraalkyl-phosphonium salts, trialkylsulphonium salts.
  • salts forming e.g. ammonium, phosphonium or sulphonium cations such as tetraalkylammonium salts, tetraalkyl-phosphonium salts, trialkylsulphonium salts.
  • One of the benefits of the addition of these salts is the depression of the undesired full hydrogenation of the double bond.
  • quaternary ammonium salts Particularly effective are the quaternary ammonium salts. Accordingly we also provide a process as described characterised by the presence of a quaternary ammonium salt.
  • the nature of the substituents on the oninm cation aifects the efficacy of our process in regard to the degree of suppression of the undesired full hydrogenation reaction such as the undesired formation of propionitrile from acrylonitrile.
  • certain pyridinium salts are considerably less effective in this respect than tetraethylammonium salts or saturated heterocyclic quaternary compounds such as piperidinium or piperazinium salts.
  • tetraethylammonium and cetyltrimethylammonium ions can be shown by means of molecular models to be capable of close packing on a surface, while tetra n-butyl and methyl tri-n-butylammonium ions which we found to be less effective appear to leave spaces between adjacent ions large enough for the access of hydrated hydrogen ions to the surface because of the three or more long butyl chains.
  • the more effective cations are to be found among the tetraalkylammonium compounds bearing at least two short alkyl radicals, which may be the same or different, where the short alkyl radical is selected from the group consisting of methyl, ethyl, propyl, isopropyl and isobutyl.
  • Said remaining two alkyl radicals may have one to twenty-four or more carbon atoms where the upper limit of chain length is given by the requirement that the resulting compound must remain appreciably soluble in the aqueous medium.
  • alkyl we may include alkenyl and alkynyl, particularly alkenyl radicals having one double bond in positions other than vicinal to the quaternary nitrogen. However, no special benefit is derived from unsaturation and alkyl is therefore preferred.
  • quaternary ammonium salts defined above substantially improve the ratio of adiponitrile to propionitrile formed over that obtained in the absence of a quaternary ammonium salt as defined, it remains a desirable target to reduce the formation of propionitrile to a level so low that in technical practice it can be discarded, i.e. does not require recovering or recycling or can even be disregarded as an impurity in the final product. Hence conversions to propionitrile less than 20% and approaching 1% are particularly desirable. We have found that particularly low propionitrile conversions are obtained in the presence of quaternary ammonium compounds having certain proportions of short, medium and long chain alkyl substituents.
  • a particularly preferred process comprises the reductive dimerisation of acrylonitrile, alkyl substituted acrylonitriles and (1, 8 olefinic acid esters and carboxamides as defined above respectively wherein in a medium capable of providing hydrogen and preferably maintained at neutral to alkaline conditions the reduction is carried out by reacting an alkali metal amalgam or an alkaline earth metal amalgam with said medium in the presence of a quaternary ammonium compound of the formula RIRIIRIIIRIVNX wherein R and R which may be the same or difierent, are selected from the group consisting of methyl, ethyl, isopropyl, n-propyl and isobutyl, R is alkyl including cycloalkyl, R is alkyl and X is an anion and wherein, optionally, any two alkyl radicals selected from the group consisting of R R and R may be linked directly or, optionally, through at least one further hetero atom selected from the group consisting of nitrogen, oxygen
  • alkyl we may include here again alkenyl and alkynyl, particularly alkenyl radicals having one double bond in positions other than vicinal to the quaternary nitrogen. However, no special benefit is derived from unsaturation and alkyl is therefore preferred.
  • alkyl radicals R and/or R which may be the same or different, may be short or long, say C to C and more where the upper limit, again, is given by the requirement that the compound must remain appreciably soluble in the reaction medium.
  • the alkyl group may be branched and may furthermore carry certain non-alkyl substituents in the carbon chain.
  • aromatic substituents must not be in the alpha position to the quaternary nitrogen; thus benzyl is unsuitable as R or R but (u-methyl-B-phenyDethyl is acceptable.
  • no further improvement is achieved by substitution in R or R and among the substituents the less polar groups, closer in character to the straight chain alkyl group, are better than polar groups.
  • acetyl choline is more effective than choline itself.
  • Solubility either in water or in acrylonitrile of thesalt capable of forming alkylated cations is desirable and high solubility is preferred; with higher amounts of Water an on of inorg nic acids g. ch o ide or b omide a satisfactory.
  • the organic anions, e.g. p-toluene sulphonate, which are more soluble in acrylonitrile, are more convenient.
  • a particularly suitable salt is tetraethylammonium ptoluene sulphonate.
  • Other preferred salts are trirnethylcetylamrnonium bromide, tetramethylammoniurn ptoluene sulphonate and trimethyl(ethyl)ammonium bromide.
  • the operative amount of the salt capable of forming alkylated cations in the reaction medium varies over wide ranges. While the benefit of the invention i.e. the depression of the formation of the nitriles and esters of the undesired fully hydrogenated alkanoic acids is appreciable at concentrations as low as 0.5 part and as high as 50 parts by weight of alkylated cationic salt per parts of acrylonitrile, concentrations between 10 and 30 parts of alkylated cationic salt per 100 parts of reaction mixture are most effective and are therefore preferred.
  • promoters are e.g. chromium compounds such as chromic chloride or sodium chromate.
  • the amount of promoter used may vary over a wide range e.g. between 1 to 50 parts per million parts of reaction mixture. However, We have established in separate experiments, e.g. Experiment No. 23, by careful removal of all analytically measurable quantities of the promoters, that the presence of promoters is not essential for the successful operation of our process.
  • the medium capable of forming hydrogen with an alkali metal amalgam is preferably water; however, the use of those lower alcohols which themselves do not react with acrylonitrile to form undesired by-products and/or mixtures of water and alcohols is within the scope of the invention.
  • the use of further polar inert solvents added e.g. so as to increase the solubility of the cation-yielding salts and/or the monomer is within our invention.
  • Suitable solvents are e.g. dioxane, acetone, dimethylforrnamide or ethylene glycol.
  • the amount of Water again, may vary over Wide ranges: relatively small amounts of water e.g.
  • the aqueous phase may separate from the organic acrylonitrile/adiponitrile phase; this does not prevent the reaction from proceeding and it further facilitates separation of the inorganic neutralisation product e.g. sodium bicarbonate from the reaction mixture as well as temperature control because the water excess assists in absorbing ny un esire sud nly evolved he t of reac ion.
  • the amount of water is not narrowly critical for the operation of the process.
  • a weak acid may be used, the alkali or alkaline earth salt of which is not so basic as to lead to the undesired pH above 9.5.
  • inorganic weak acids are preferred.
  • a well-known convenient method of pro ducing a weak acid is the addition of a strong acid to a buffer, e.g. the addition of phosphoric acid to a sodium dihydrogen-phosphate/disodium-hydrogen phosphate buffer system.
  • a convenient and preferred method of controlling the pH between 7 and 9.5 is the addition of carbon dioxide by maintaining in the reaction vessel a suitable concentration of the gas and promoting the rate of solution of the gas in the reaction liquid e.g. by agitation of the liquid.
  • An atmosphere of pure carbon dioxide is preferred because it avoids the complications resulting from recovery of gaseous acrylonitrile from a large inert gas stream. Slightly superatmospheric pressure is convenient, but higher and even reduced pressures may be used.
  • the bicarbonate of the alkali metal is formed and precipitated. Conveniently it may be separated e.g. by intermittent filtration or by continuous filtration e.g. by circulating part of the reaction mixture through a filter, so as to avoid the contamination of the reaction mixture with large amounts of the neutralisation product.
  • alkali metal amalgams it is possible to use the amalgams of the alkaline earths. In normal commercial practice, however, sodium or potassium amalgams are preferred since these are readily available from large scale processes and the corresponding neutrallsation byproducts are of commercial value.
  • the content of alkali or alkaline earth metal in the amalgam may also vary over wide ranges from saturation point to minute concentrations; since under our process conditions the amalgam decomposes rapidly the actual concentration in operation is not easily assayed. Depending on reaction conditions lower concentrations, e.g. below 0.1% of sodium in mercury, are convenient when excessive evolution of heat is to be avoided.
  • Ambient temperatures between 10 and 35 C. are suitable for the reaction and are preferred, but both lower and higher temperatures may be used.
  • temperatures above 35 C. may be desirable so as to reduce the formation of higher molecular weight hydrooligomers as well as for chemical engineering reasons; since an appreciable temperature differential between reactants and cooling water is necessary for heat transfer, operation above 35 C. may be desirable to avoid the need to use refrigeration for cooling.
  • the temperature range preferred on technical scale is therefore wider, between the freezing point of the aqueous medium and 60 C.
  • Suitable inhibitors are the polymerisation inhibitors known from the technology of polymerisation of vinyl monomers.
  • a particularly suitable, preferred inhibitor is N,N-dimethyl p-nitrosoaniline.
  • N,N-dimethyl p nitrosoaniline is effective in suppressing the formation of polymer.
  • the reactor may e.g. consist of a closed vessel, preferably provided with a relatively fiat bottom, permitting the formation of a large surface area for the amalgam; an inlet or inlets for the liquid reactants and water together with promoter, if used, cationic salt and polymerisation inhibitor; an inlet for the acidifying substance which, when carbon dioxide is used, conveniently may be a dip tube with a porous gas distributor immersed in the water-monomer phase; a cooling coil or jacket in contact with the aqueous and/ or amalgam phase; a stirrer which may be adjusted to agitate the aqueous phase and/or amalgam phase or a separate stirrer for either phase; an outlet for the reactants and, preferably, a separate outlet for the aqueous phase and for removal of the precipitated neutralisation product e.g. sodium bicarbonate.
  • the reactor may e.g. consist of a closed vessel, preferably provided with a relatively fiat bottom, permitting the formation of a large surface area for the amalgam; an inlet or
  • the reactants are fed continuously, in the proportions of the desired steady state reaction; a proportion of the acrylonitrile/water phase, containing the precipitated salt is removed continuously, the salt is separated e.g. by centrifuging and the filtrate is recycled to the reactor. Another portion or alternatively a fraction of said filtrate, is discharged and worked up to yield the desired hydrodimer and the unconsumed raw materials.
  • the two phases may flow lengthwise horizontally through the reactor, which may be a pipe or trough, from inlet to outlet is avoided; consequently there is a falling concentration gradient of alkali metal in the amalgam and a rising concentration gradient of acrylonitrile dimer from the entry to the outlet of the reactor.
  • the product is worked up by separation of the liquid phases e.g. by decantation, removal of solid salt as described, fractional distillation or solvent extraction of the aqueous monomer/hydrodimer/cationic salt phase in a manner known per se and the unreacted raw material is recovered.
  • alkyl substituted acrylonitriles throughout this specification, we mean acrylonitrile hearing at least one alkyl substituent having up to 4 carbon atoms in the a or ⁇ 3 carbon atoms joined by the double bond.
  • alkyl we may wish to include alkenyl and alkynyl where the unsaturated bond is not adjacent to the 11,,8 double bond of the acrylonitrile.
  • alkyl we may wish to include alkenyl and alkynyl where the unsaturated bond is not adjacent to the 11,,8 double bond of the acrylonitrile.
  • the 0a, ⁇ ? mono-olefinic mono-or di-carboxylates are equivalent to the corresponding nitriles.
  • One advantage of our invention is the high yield of the hydrodimer attainable, up to of the monomer used.
  • the actual yield of the hydrodimerisation reaction itself may be even higher, as the losses in the laboratory experiment occur principally during the work-up and are likely to be reduced on technical scale.
  • a further advantage resides in the high conversion of acrylonitrile attainable.
  • Yet another advantage resides in the fact that the reaction occurs in the absence of an external electrical circuit. This is a useful result as the amalgam can be formed separately at high electrochemical efficiency and low voltage, no diaphragm is required and the anode reaction may be used for some other useful purpose such as the manufacture of chlorine, as e.g. in the large scale caustic/ chlorine manufacture in mercury cells. In addition the sodium or other alkali metal from the decomposition of the amalgam can be converted into yet another useful byproduct.
  • EXAMPLE 1 The reactor consisted of a closed 250 ml. Erlenmayer flask, fitted with a Quick-fit dropping funnel; a sealedin tube for the introduction of carbon dioxide and a water bath, used to keep the reaction temperature at approximately 20 C.
  • a solution was prepared containing 15.17 g. acrylonitrile, 6.86 g. tetraethylammonium p-toluene sulphonate, 1.07 g. water, 0.43 g. chromic chloride (CrCl -6H O) and 20 microgrammes N,N-dimethyl p-nitrosoaniline. This was added to the reactor containing 20 ml. mercury which reactor had been flushed out with carbon dioxide. A slight positive pressure of carbon dioxide was maintained in the vessel during the reaction.
  • 60 ml. of sodium amalgam was prepared by electroylsing a 40% w./v. aqueous solution of sodium hydroxide between a platinum foil anode of cylindrical shape having a surface area of 1 in. and a mercury pool cathode of a surface area of 4 in. at a current flow of 4 amps.
  • the amalgam was run from the cell and dried. A portion of this amalgam was found by hydrogen evolution to give 1.22 mg. of hydrogen per ml. of amalgam. 25.6 ml. of amalgam was added to the reaction vessel over a period of 20 minutes. During this time and for an extra 7 minutes after the addition the flask was shaken vigorously by hand.
  • the unreacted acrylonitrile was distilled from the vessel under reduced pressure.
  • the weight of recovered acrylonitrile was 13.11 g.
  • the reaction vessel was washed out three times with 20 ml. of water per washing, followed by five washings with 8 ml. methylene chloride per washing.
  • the aqueous phase was extracted seven times with 8 ml. of methylene chloride each time.
  • the combined methylene chloride washings were extracted twice with 15 mls. of water, then the methylene chloride was evaporated off over a water bath.
  • the residue after evaporation was heated to 130 C. for 10 minutes to drive off any residue of water.
  • the weight of the residue was 1.64 g.
  • EXAMPLE 2 To the reactor as described in Example 1, which had been flushed out with carbon dioxide, were added two solutions; the first solution contained 4.0 g. of trimethylcetylammonium bromide, 0.43 mg. of chromic chloride (Cr.Cl 6H O) in 10.10 g. of water; the second solution contained 20 microgrammes of N,N-dimethyl p-nitrosoaniline in 8.17 g. of acrylonitrile; furthermore 20 ml. of mercury was added to the reactor.
  • the first solution contained 4.0 g. of trimethylcetylammonium bromide, 0.43 mg. of chromic chloride (Cr.Cl 6H O) in 10.10 g. of water
  • the second solution contained 20 microgrammes of N,N-dimethyl p-nitrosoaniline in 8.17 g. of acrylonitrile; furthermore 20 ml. of mercury was added to the reactor.
  • ml. of sodium amalgam was prepared in a cell identical to that in Example 1. A current of 4.3 amperes was passed through the cell for 82 minutes. The amalgam was run from the cell, dried and stored in the dropping funnel under an atmosphere of nitrogen. A portion of this amalgam was found by hydrogen evolution to give 2.57 mg. of hydrogen per ml. of amalgam. 41.5 ml. of this amalgam was added to the reaction vessel over a period of 33 minutes. During this time and for a further 5 minutes after the addition the flask was shaken vigorously by hand. The temperature was maintained at about 20 C. by partial immersion of the flask in a bath of tap water.
  • the amalgam dropping funnel was removed, 20 ml, of water was added to the flask and a Dean and Starke apparatus was fitted to the flask. The flask was heated and 2.95 ml., i.e. 2.36 g. of unreacted acrylonitrile was recovered in the Dean and Starke apparatus. The contents of the flash were transferred to a separating funnel.
  • the reaction vessel was Washed out three times with 10 ml. of methylene chloride.
  • the aqueous phase was extracted six times with 10 ml. of methylene chloride.
  • the combined methylene chloride was evaporated from the combined extracts and the residue obtained from this was heated to 130 C. for 10 minutes to drive 01f any residue of water.
  • the weight of the residue was 5.65 g. 'On infrared and gas chromatographic analysis this appeared to be substantially pure adiponitrile free from propionitrile, but subsequently oligomeric impurities were detected in the crude product by liquid chromatographic analysis.
  • the purpose of the experiments was to establish to what extent the range of the principal experimental parameters is critical; the product as obtained was analysed by gas chromatography and the main effect, namely the relative proportion of adiponitrile to propionitrile was determined, i.e. the depression of the propionitrile formation was assayed and the formation of impurities and/or polymer was observed. The amount of oligomeric impurities formed from acrylonitrile was not determined.
  • Results are summarised in Table 1.
  • concentrations of the reactants are expressed as molar percent, 100% being the sum of water, acrylonitrile and the cationic salt; the concentration of acrylonitrile-not shown-is the balance to 100%.
  • the relative proportions of the two principal reaction products, adiponitrile and propionitrile, are expressed as Weight percent.
  • Examples 3 and 4 demonstrate yields obtainable outside this invention and indicate the large amount of propionitrile formed.
  • Examples 5, 6 and 7 demonstrate the depression of the formation of propionitrile in the presence of quite small amounts of cationic salts according to this invention.
  • Examples 8 to 16 demonstrates the suppression of propionitrile formation in the presence of several quaternary ammonium salts at varying concentration of quaternary salt, water, aerylonitrile, promoter and polymerisation inhibitor.
  • Examples 8 and 9 approach the lower limit of water concentration at which exhaustion of water during the reaction with the concomitant formation of a yellow by-product can be conveniently avoided.
  • Examples 17 to 19 demonstrate the suppression of propionitrile at somewhat lower acrylonitrile/water ratios i.e. at higher water concentrations which facilitated the removal of sodium bicarbonate. In Example 19 the reaction mixture consisted of two phases, an aqueous phase containing essentially all the sodium bicarbonate and an organic acrylonitrile/adiponitrile phase which readily of the sodium bicarbonate.
  • Example 20 demonstrates very high water content.
  • the reactor consisted of 5 l. three-necked round bottom Pyrex glass flask having an outlet fitted with a tap in the bottom.
  • the flask was provided with a sealed in dip-tube reaching near the bottom of the inside of the flask, so that during operation its outlet was well submerged in the reaction mixture, and connected to a source of carbon dioxide.
  • a sealedgland glass stirrer was fitted; to the second neck a 500 ml. separating funnel serving as reservoir for the amalgam was connected and the third neck used as the gas exit line was connected to two liquid traps immersed in Dry Ice/acetone and was then vented to atmosphere.
  • a ring shaped distributor was mounted around the top half of the flask, so that an adjustable flow of cooling water could be passed over the outside of the flask,
  • the reaction mixture consisting of:
  • the solution remaining in the flask was transferred to a 1 l. separating funnel and approximately 1 l. of water was added. This solution was extracted five times with ml. lots of methylene chloride. The two phases separated out in approximately 1 hour in the first extraction. However, in later extractions, more and more stable emulsions were formed. It became necessary to centrifuge these emulsions for a considerable time to achieve phase separation. The methylene chloride extract was washed four times with small lots of water, and was then transferred to a weighed flask.
  • the remaining liquid in the flask was transferred to a separating funnel, and the aqueous and organic phases were separated.
  • the organic phase was washed three times with 25 ml. lots of saturated brine, then dissolved in -1S0 ml. methylene chloride and washed twice with 50 ml. lots of water. The washings were added to the aqueous phase.
  • the methylene chloride extract was transferred to a weighed flask. The volatile materials were stripped off under reduced pressure (70 C. at 20 mm. Hg.) and the remaining non-volatile liquid was weighed.
  • the aqueous layer was transferred to a 3 l. beaker and the volume was brought up to 1500 ml. with water.
  • the pH was adjusted to approximately 7 using concentrated ammonia.
  • a solution of 100 g. Na Cr O containing a quantity of Celite 535 filter aid (registered trademark) was added slowly while stirring vigorously.
  • the precipitated complex (Cetavlon 3Na Cr O see Ref. I. Renard J. Pharm. Belg. 7, 403-8 (1952)) was filtered off, and washed once with water.
  • the precipitate was dissolved in 300 ml. hot acetone and reprecipitated by adding it slowly while stirring to approximately 2 1. water. This precipitate was filtered oif.
  • the quaternary ammonium compound was purified by two recrystallisations; once-distilled water water and acrylonitrile were purified by distillation.
  • Mercury of Analar purity was purified further by passing it three times in fine droplets through a 3 ft. high column of 20 nitric acid (analytical grade).
  • reaction mixture was made up from the purified reagents as:
  • the reaction vessel consisted of a 250 ml. three-necked flask having an outlet in the bottom. A dip-tube was provided as carbon dioxide gas inlet. The carbon dioxide gas outlet connected to two traps immersed in a carbon dioxide/acetone bath and a glass stirrer were also fitted, all as described in Example 22.
  • the vessel was flushed out with carbon dioxide. Stirring of the aqueous/ organic phase was commenced and amalgam was slowly added to the vessel from a dropping funnel. The flask was placed in a water bath for cooling. The temperature of the reaction was kept below 35 C. Amalgam addition was stopped when the amount of precipitated sodium bicarbonate made the etficient stirring of the solution difficult. The carbon dioxide inlet was removed and concentrated hydrochloric acid was slowly added to the solution from a dropping funnel until the sodium bicarbonate had been destroyed. The spent amalgam was run off, and the remaining contents of the vessel were transferred to a flask. This was connected for distillation and the unreacted acrylonitrile was distilled over.
  • the liquid remaining in the flask was transferred to a separating funnel and the organic layer was separated off. This was washed four times with a saturated sodium chloride solution and the washings were added to the aqueous layer. The volatile materials were stripped from the washed organic layer under reduced pressure, and the remaining non-volatile matter was weighed.
  • the pH of the aqueous layer was adjusted to 7 with ammonia, and distilled water was added to bring the volume to about 400 ml.
  • a solution of 10 g. Na Cr O in 50 ml. of water containing Celite filter aid was added slowly with stirring.
  • the precipitate formed was filtered off and washed several times with water. It was then dissolved in approximately 40 ml. of acetone and reprecipitated by the addition of 500 ml. of water.
  • the precipitate was filtered olf and washed a number of times. The filtrates and washings were combined and extracted six times with 50 ml. lots of methylene chloride.
  • the reaction mixture was worked up as described in Example 1 and the adiponitrile was analysed by gas liquid chromatography. No propionitrile was detected; the yield of the crude product on acrylonitrile was better than 99%, purity of the crude adiponitrile was better than 70%, i.e. the yield of pure adiponitrile was about 70%.
  • EXAMPLE 25 A magnesium amalgam was prepared by shaking mercury with an excess of magnesium filings in a separating funnel and running out the amalgam so formed. The amalgam was prepared and handled under an atmosphere of nitrogen. This amalgam was then substituted for the sodium amalgam in a hydrodimerisation reaction of acry-' lonitrile as described in experiments 3 to 20 inclusive.
  • the quaternary ammonium salt was cetyltrimethylammonium bromide (1 mole percent), water content was 16 mole percent, N,N-dimethylparanitrosoaniline was 1 p.p.m., Cr+++ content was 5 p.p.m.
  • EXAMPLES 2668 A further series of small scale experiments as described for Examples 3 to 20 was carried out to determine the etfectiveness of other compounds capable of forming alkylated cations. Results are given in Table II and are expressed in the same manner as described for Examples 3 to 20.
  • the experimental arrangement was as described for Example 23 using, however, commercial grade, unpurified chemicals.
  • the reaction mixture consisted of:
  • EXAMPLE 71 The reactor described in Example 1 was charged with 20 mls. of mercury, flushed with carbon dioxide and then 0 a mixture was added consisting of g. of ethyl acrylate,
  • the reaction was conducted in a closed jacketed 3-necked glass vessel of 350 ml. capacity, fitted with a glass stirrer.
  • Amalgam as prepared in Example 1 flowed through the vessel at a controlled rate by means of inlet and outlet tubes in the base of the reactor, the depth of mercury being maintained at a level of 0.5 cm.
  • Temperature was 32:3 C.
  • Examples 73, 76 and 79 demonstrate the reaction in the absence of a quaternary salt; Examples 74, 77 and 80 demonstrate the reaction in the presence of 30 g. of triethylmethylammonium p-toluene sulphonate and Examp es 75 78 and 81 demonstrate the reaction in the pres- 17 once of 30 g. of trimethylcetylammonium bromide.
  • the following further reagents were added: 13.2 g. of acrylonitrile, 0.012 mg.
  • Experiments 82, 83 and 84 apparatus, conduct of the experiment, work-up and analysis were as described in Example 81 using, however, 100 g. of water, g. of cetyltrimethylammonium bromide, 0.015 mg. of N,N-dimethyl p-nitrosoaniline and acrylonitrile in the molar proportions indicated in Table IV.
  • Experiments 85, 86 and 87 were conducted essentially in a similar manner on semi-technical scale in a continuous (steady state) glass reactor where the collected reaction mixture after completion of the run was about 5 1. volume. Results, indicating the reduced proportion of higher hydro-oligomers at higher water/acrylonitrile ratios, are g1ven 1n Table IV.
  • liquid medium contains in solution therein from 0.1 to 10 mole percent of a quaternary ammonium salt as the source of said alkylated onium cations, and the molar ratio of acrylonitrile to water in said liquid medium is within the range of from 10:1 to 1:70.
  • liquid medium further contains dimethyl formamide.
  • salt is a quaternary ammonium salt which is soluble in said medium, said salt having the formula:
  • R R R R NX wherein X is an anion, R and R separately, are selected from the group consisting of methyl, ethyl, propyl, isopropyl and isobutyl, R is selected from the group consisting of alkyl of from 1 to 24 carbon atoms, cyclopentyl and cyclohexyl, and R separately represents alkyl of from 1 to 24 carbon atoms, or R and R together form with the quaternary nitrogen atom a saturated heterocyelic ring optionally containing in the ring, in addition to the said nitrogen atom and carbon atoms, a single nitrogen, oxygen or sulphur atom.
  • R R and R are selected from the group consisting of methyl and ethyl.
  • a process for the hydrodimerization of acrylonitrile to form adiponitrile which comprises intimately contacting a preformed sodium amalgam with an aqueous solution of acrylonitrile having dissolved therein an alkylated quaternary ammonium salt, the cation of which is selected from the group consisting of tetramethyl ammonium, tetraethyl ammonium, methyl triethyl ammonium and cetyl trimcthyl ammonium and the anion of which is selected from the group consisting of toluene sulphonate, bromide and chloride, at a temperature of 10 to 60 C., maintaining the pH of said solution between 7.0 and 9.5 during said contact and recovering the resulting adiponitrile, said solution containing from 0.5 to 50 parts by weight of said quaternary ammonium salt per 100 parts of acrylonitrile and the molar ratio of acrylonitrile to water therein being in the range of 10:1 to 1:20.

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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US446430A 1964-04-16 1965-04-07 Process for the reductive dimerization of alpha,beta-olefinicallyunsaturated nitriles or esters Expired - Lifetime US3489789A (en)

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AU43311/64A AU279319B2 (es) 1964-04-16
AU48630/64A AU292745B2 (en) 1964-08-27 Amalgam hydrodimerisation process of olefinic nitriles and esters

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US3489789A true US3489789A (en) 1970-01-13

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US (1) US3489789A (es)
BE (1) BE662661A (es)
CH (1) CH504401A (es)
DE (1) DE1543062B1 (es)
GB (1) GB1063497A (es)
NL (1) NL140514B (es)
SE (1) SE329839B (es)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855269A (en) * 1972-07-27 1974-12-17 Phillips Petroleum Co Apparatus and method for separating tetraalkylammonium salt
US3890365A (en) * 1965-06-30 1975-06-17 Ici Ltd Organic reduction process
US10614010B2 (en) 2015-11-16 2020-04-07 International Business Machines Corporation Handling queued interrupts in a data processing system based on a saturate value

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140276A (en) * 1961-07-11 1964-07-07 Exxon Research Engineering Co Continuous electrolytic polymerization process
FR1366081A (fr) * 1963-05-24 1964-07-10 Rhone Poulenc Sa Dicyano-2, 4 butène-1
US3193477A (en) * 1962-04-20 1965-07-06 Monsanto Co Electrolytic hydrodimerization process and extraction procedure
US3193480A (en) * 1963-02-01 1965-07-06 Monsanto Co Adiponitrile process
US3225083A (en) * 1963-08-15 1965-12-21 Shell Oil Co Dimerization process of preparing 1,4-dicyano-1-butene from acrylonitrile
US3245889A (en) * 1963-02-25 1966-04-12 Monsanto Co Electrolytic method for preparing low weight polymers of acrylonitrile
US3250690A (en) * 1963-12-23 1966-05-10 Monsanto Co Electrolytic reductive coupling of cyano compounds
FR1472033A (fr) * 1965-03-18 1967-03-10 Rhone Poulenc Sa Procédé de dimérisation linéaire de l'acrylonitrile

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1289071A (fr) * 1961-05-04 1962-03-30 Procédé de préparation de l'adiponitrile par dimérisation de l'acrylonitrile
FR1325977A (fr) * 1962-05-23 1963-05-03 Knapsack Ag Procédé de préparation de dérivés d'acides dicarboxyliques aliphatiques

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140276A (en) * 1961-07-11 1964-07-07 Exxon Research Engineering Co Continuous electrolytic polymerization process
US3193477A (en) * 1962-04-20 1965-07-06 Monsanto Co Electrolytic hydrodimerization process and extraction procedure
US3193480A (en) * 1963-02-01 1965-07-06 Monsanto Co Adiponitrile process
US3245889A (en) * 1963-02-25 1966-04-12 Monsanto Co Electrolytic method for preparing low weight polymers of acrylonitrile
FR1366081A (fr) * 1963-05-24 1964-07-10 Rhone Poulenc Sa Dicyano-2, 4 butène-1
US3225083A (en) * 1963-08-15 1965-12-21 Shell Oil Co Dimerization process of preparing 1,4-dicyano-1-butene from acrylonitrile
US3250690A (en) * 1963-12-23 1966-05-10 Monsanto Co Electrolytic reductive coupling of cyano compounds
FR1472033A (fr) * 1965-03-18 1967-03-10 Rhone Poulenc Sa Procédé de dimérisation linéaire de l'acrylonitrile

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3890365A (en) * 1965-06-30 1975-06-17 Ici Ltd Organic reduction process
US3855269A (en) * 1972-07-27 1974-12-17 Phillips Petroleum Co Apparatus and method for separating tetraalkylammonium salt
US10614010B2 (en) 2015-11-16 2020-04-07 International Business Machines Corporation Handling queued interrupts in a data processing system based on a saturate value

Also Published As

Publication number Publication date
CH504401A (de) 1971-03-15
GB1063497A (en) 1967-03-30
NL6504863A (es) 1965-10-18
SE329839B (es) 1970-10-26
DE1543062B1 (de) 1972-11-16
NL140514B (nl) 1973-12-17
BE662661A (es)

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