DE1468411A1 - Process for the preparation of dimers of acrylonitrile compounds - Google Patents

Description

D R.-1N G. WA LTE R A BITZ 8 Munich 27, Pienzenauerstraße

DR. DIETER MORF Telephone 483225 and 486415

Telegrams: Chemindus Munich Patent attorneys

August 1st l ⁽ jt>'<~> A-53 108 / H 24

p 14 68 411. 8 1468411

New documents

NATIONAL UZSTZLISRS AND CHEMICAL CORPORATION 99 Park Avenue, New York 16, N.Y., V.St.A.

Process for the preparation of dinners from Aory! Nitro compounds

Thermal processes for the dimerization of acrylonitrile compounds are known. Thus, in German Patent 855,544 and US Patent 2,232,785 mentions, Aerylnitrilverblndungen to higher temperatures, preferably above 200 ⁰ C to heat. According to the teaching of US Patent 2,566,203 eieren temperatures of 300 to be applied to 400 ⁰ C for dimer!. Also known are catalytic "processes for polymerizing acrylonitrile compounds. These known processes do not, however, produce dimers, but rather higher molecular weight polymers". US Pat. The molecular weight can be reduced by adding water. However, dimeric products are not obtained as a result. After the in Journ. At the. Che. Soc, Vol. 84, (1962), pages 489 to 491, is obtained as the product of the polymerization of acrylonitrile in the presence of triphenylphoaphine and an alcohol, mainly hexaeric acrylonitrile.

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Ee has now become a catalytic process for dimerizing Acrylonitrile compounds found in which unsaturated dinitrile in practical yields arise which lead to diamines, which are particularly valuable in the field of synthetic fibers let reduce.

The purpose of the invention is to provide a process for converting acrylonitrile compounds into dinate unsaturated dinitriles while avoiding the formation of high molecular weight polymers in substantial quantities. Another purpose of the invention iat the production van linear dining of Aeryloau ^ eaitril, especially 2-ITrithy3 anglutarsäuren! _Tril? in practical yields.

6omäs8 of the invention are acrylonitrile compounds in one Solvent at moderate temperatures to unsaturated Dinitrile dimorized, with tertiary phosphines as catalysts of the addition products of tertiary phosphines and of Nickel carbonyl derived zero valent nickel catalysts can be used.

All starting materials in the process according to the invention particularly suitable acrylonitrile compounds have the general formula

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in which R ₁ , R ₂ and R »together or individually can denote hydrogen atoms, alkyl or aryl radicals; preferably H ^ is a hydrogen atom. The preferred compound is acrylic acid nitrile. Other acrylonitrile compounds are methacrylonitrile, phenyl acrylonitrile, ethyl acrylonitrile, ziete acid nitrile, fumaric acid nitrile, 2-cyano-3-methylbutene-2, etc.

Depending on the catalyst and the reaction conditions, branched-chain, linear or cyolic dimeric dinitriles are formed in the process according to the invention. If you start from aoryl nitrile, the branched-chain dimer 2-methylenglutaronitrile (bp _c __. «

OH ₂ ^5MI

103 C) of the formula NC-CH ₂ -CH ₂ -O-CN together with smaller amounts of other dimers and some polymer.

Tertiary phosphines that can be used as catalysts include the trialkylphosphines, the triarylphosphines and the mixed ones Alkylarylphosphines The aryl group can also be a hetero be rocyclisoher remainder. Examples of such tertiary phosphines are trimethylphosphine, triethylphosphine, tri- (n-propyl) - phosphine, tri- (isopropyl) -phosphine, tri- (n-butyl) -phoephine,

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Tri = (n-oetyl) -phosphine, triphenylphosphine, tricyclohexylphosphine, Ethyldiphenylphosphine, dichlorophenylphoaphine and the like. The preferred phosphines are the trialkylphosphines or die. Mischten Dialkylarylphoephine, in which the alkyl group contains about 4 to 8 carbon atoms, and special Tri- (n-bu-fcyX) -phosphine, Sri- (n-octyl) -phosphine and di- (n-ootyl) -phenylphosphine.

Zero-valent nickel addition compounds of the tertiary Phos _r phine can also be used as catalysts of the invention genäse be used. These catalysts include compounds of the general formula derived from nickel carbonyl

in which R denotes an alkyl, aryl radical or a heterocyclic bed and η has the value 1 or 2.

Suitable catalysts are also the zero-valent nickel catalysts of the general formula

in which A is a tertiary phosphine (R ₅ P) as defined above and B is aoryl nitrile, cinnamonitrile, funaric acid nitrile or acrolein.

Compounds of the above general structural formula in which A is zero (the parent compounds) were used in the

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Production of a group of complex compounds of the general formula Ni (ligand) ₂ and the ligand is acrylonitrile, cinnamonitrile or acrolein. These compounds are obtained, for example, by heating nickel carbonyl with the ligand for several hours in an anhydrous solvent or in a large volume of the ligand participating in the reaction at reflux temperature.

The addition links are made by using the parent V link in a solution of the various tertiary phosphines under an inert atmosphere at reflux temperature is heated until a clear change in color occurs, the reaction times being about 4 to 20 hours. The monoadition connection arises when the ratio of parent compound to ligand is 1; 1 is. The bis addition compound is generally only acceptable if the ligand is in a considerable amount Excess is present. It is required under exclusion to work from atmospheric oxygen, and therefore all work, such as loading the reaction vessel, becomes »that Filtration, drying and chasing of the complex compounds under an inert atmosphere.

The yield of aoryl nitrilization varies with the concentration of the catalyst. The catalyst is in a concentration * tv tion from about 0.1 to K; Weight percent aoryl nitrile compound

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applied. At higher catalyst concentrations, a large amount of dimer does not appear to be formed, but in in this case increase the amount of polymer. The best concentration depends on the phosphine used.

Alcohols can be used as auxiliary catalysts together with the tertiary phosphine. Certain alcohols are more effective than others. Alcohols of 5 to about 18 carbon atoms are preferred, with alcohols of 3 to 10 carbon atoms likely to give the best results. The aliphatic alcohols can be primary, secondary or tertiary, third-octave chain or straight-chain and also contain unsaturated carbon-carbon bonds. The preferred alcohol for this purpose is isopropanol. Examples of suitable alcohols are isopropyl alcohol, n-butyl alcohol, beta-butyl alcohol, tert-butyl alcohol, isoamyl alcohol, tert-amyl alcohol, benzyl alcohol, triphenyloarbinol, allyl alcohol, 1,1,5-H-octafluoropentanol-1,2-methylpentanol, 2 , 2 ^I -Dimethylpentanol, n-hexyl alcohol, 2-A "thylhexanol, Hexadecy! alcohol, cyclohexanol, menthol and the like. the presence of the alcohol can reduce the forming polymer the amount.

The particular concentration of alcohol added is unimportant and can range from about 1 to 20 pounds.

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With tertiary phosphines as catalysts, slightly different results are obtained with the nickel addition compounds of the tertiary phorphines, although the two types of catalysts can be equally effective under suitable working conditions. In general, less undesirable polymer is obtained with the nickel addition compounds, and these catalysts can be used in higher concentrations. At concentrations of the nickel addition compound of more than 3 t, based on the solvent, increasing amounts of polymer can form, while the amount of dimeram does not noticeably increase. On the other hand, can cause the Aoryloäurenitrils concentrations of trialkylphosphine of greater than about 1 i "ZVx immediate and violent polymerization. Possibly the release of the phosphine is controlled by the nickel addition compound and thereby the polymerization is inhibited and only the dimerization is catalyzed.

The yield of the dimer varies with temperature. the Dimerization reaction can take place at temperatures below 0 ° C, e.g. up to about -40 ° C, and up to about 100 ° C. The preferred temperature range is about 20 to 60 ° C. With certain phosphines, the reaction takes place at temperatures from 0 ° C to room temperature quickly, with others there is some heat input necessaryο

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You can work for the Yerechiedeneten Druck. E.g. can the dimerization according to the invention at atmospheric pressure be performed. On the other hand, you can also work at high pressures of 100 at.

The dimerization reaction can be carried out in coal water flow, such as benzene or xylene, or in solvents that do not split off protons, such as dimethylformamide, dimethylacetamide, Aoeton or acetonitrile »can be carried out. Acetonitrile is preferred as a solvent. In solution in hydrocarbons so the addition of small amounts of alcohol is beneficial.

act, although a certain amount of the alcohol prefers an equilibrium cyanoethylation reaction before the dimerization suffers.

A polymerization inhibitor, such as p-tert-butyl catechol, can also be added. The preferred amount is in the range from about 0.1 to 5 parts by weight of the acrylonitrile. if less than 0.05 # inhibitor is used, forms eioh sunny a small amount of polymer in the aoryl nitrile.

The aoryleonitrile. is preferably slow, alone or im Mixture with a solvent to a rapidly stirred dilute Added catalyst solution. The addition should be about 0.5 take up to 2 hours. During this time, the temperature should be kept constant by dissipating or adding heat.

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When the reaction has ended, the catalyst is treated with acid » preferably an organic acid »such as propionic acid» neutralized. At this point in the process, additional inhibitor can be added to suppress further polymerization. Bas solvent and the unreacted acrylonitrile are distilled off, the temperature being kept below about 100.degree. The rest of the acetonitrile can by means of azeotropic distillation, e.g. with benzene. The Pho sphoni urn ale is made from the raw dinners duroh extraction removed with dilute acid. The inner and the Solvents used for the azeotropic distillation containing organic solution are diluted with water and with Washed vatriun bicarbonate solution. Then the solvent is distilled off. The crude diner is made by vacuum distillation won.

The catalyst is extracted from the aqueous solution after adding alkali with benzene or another solvent and circulated.

At BPi e 1 1

Two 10 nl stainless steel pressure tubes with a valve one end is nit a reaction mixture from 0.5g frisoh ground Oaloiunoarbld, 0.3 nl of an 8.5 Jllgen solution of Tri- (n-butyl) phosphine in xylene and eohliesslioh nit 3.0 nl

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Aoryleonitrile, which contains 0.1 56 p-tert-butylpyrocatechol as a stabilizer, is charged. 0.15 oil of tert-butyl alcohol is added to a tube. After charging the reactants, the tubes are purged with nitrogen and then saueretofffreien in an oil bath for 3 hours at 70 ° C, then heated for 4 hours at 70 ° C for 2 1/2 hours at 110 ⁰ C and sohliesslioh 16 hours 70 ° C. Samples are taken after each of the above reaction periods and analyzed by vapor phase chromatography. The results can be found in the table below.

I a b e C. 1.1 I Dimers, i » Educated without alcohol with alcohol 2.6 3.2 5.4 4.0 7.0 8.1 8.7 13.5

3 hours at 70 ° 0 7 hours at 70 ° 0 + 2 1/2 hours at 110 ° C + 16 hours at 70 ° C

About 50 % of the acrylonitrile are recovered unchanged.

Example 2

A 10 ml pressure tube fitted with a valve at one end stainless steel becomes old a reaction mixture 0.5 g of freshly ground calcium carbide, 6.0 oil of aoryleic acid nitrile,

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0.1 # ρ-tert.Butylbrenzcatechin ale Stabilisiernittel contain 1.0 Ieopropanol al and 0.6 ml of xylene containing bending _i / ^ ri- (n-butyl) -phoBphin7-nickeldioarbonyl. After filling in the reactants, the tubes are flushed with oxygen-free nitrogen and then heated to 80 ° C. in an oil bath for 2 hours. The following concentrations of diners are found:

Table II

Catalyst-
concentration, £ Yield to
Dinerem, £ 0.1 1.3 0.5 2.0 1.0 5.2 2.0 11.0

About 70 1 · the original acrylic acids! Trils have remained unchanged at the end of the reaction.

Example 3

0.5 al tri-n-butylphosphine are placed in a flask under nitrogen Dissolved in 50 nl acetonitrile. The solution is stirring at 45 ° C at a rate of about 20 nl / hour. from a dropping triohter with a solution of equal parts of aoryl acid nitrile, welohee nit 0.1 p-tert-butylbrensoateohln

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stabilized 1st, and acetonitrile added. Pie implementation is running rapidly forming the dinar, with eioh the solution discolored. After adding 25 to 30 nl of solution (about 1 1/2 hours) the dimerization stops. (The zueats of excess Äcrylaäurenitril is harmless).) The catalyst is nit 0.5 »1 propionic acid neutralized.

Most of the acetonitrile and the unreacted acryleonitrile are distilled off at a temperature below 100.degree. The remainder of the acetonitrile is removed by adding 100 αϊ benzene and distilling off the azeotropic Geaisches (bp β 71 ° C; 34 1 » acetonitrile). The crude product is in solution in benzene along with the phosphonium salts. The latter is separated from the crude product by extraction with dilute aqueous sulfuric acid. Then the bensol solution is washed with water and dilute vatric acid bicarbonate solution. The benzene is distilled off and the crude product obtained by vacuum distillation; KpK _00n * 100 ° C.

The aqueous acidic solution of the phosphine can be mixed with alkali under an inert atmosphere and extracted with benzene are »to recover the phosphine for circulation.

The yields of diners using the above process, catalyst, solvent and the specified temperature can be found in Table IXI. , -

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a b e 1 1 e III

JtÖMXXÜRBWQ.

(50Λ)

middle

Xylene

Acetonitrile

M.
Il

Diaethylformaid

Xylene

Acetonitrile

of the
talyea-
Katalyeator gates, nl 10 rature,
⁰ O Spoil
to die- Triethylphoephine 2 0 rieat Tri- (n-butyl) phoephine 2.5 40 4.2 Tri- (n-ootyl) phoephine 2.5 0 4.0 N W N 0.5 80 11.0 η η m 10 40 4.0 Diphenylethylphoephine 10 0 2.0 it η ν 0.3 60 16.0 Triethylphoephine 2.0 40 3.7 Tri- (n-toutyl) phoephine 0.9 40 4.5 Tri- (n-ootyl) phoephine 0.4 40 3.7 Diphenylethylphoephine 0.6 60 4.0 Di- (n-ootyl) -phenyl-
phoephin 0.9 50 5.8 Tri- (n-ootyl) phoephine 2.0 40 2.8 Triethylphoephine
liokeltrioarbonyl 2.6 50 1.1 Tri- (n-butyl) -phoephine-
Niokeldioarbonyl 2.6 40 2.2 • do η 40 7.2 - 13 - 8AD ORIGINAL 809811/1127

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The yield under these conditions is 3.7 g DiDieross per 0.3.5 triethylphosphine or 40 moles of product per mole of catalyst. The Uniwaadlungagrad is 35% with a selectivity for the dimes?! © atisn of about 70 Me 75 i » and for the polymerization τοη 25 to 30 #.

! as T ^ iäüylplioephii-Üiickültricarbonyl and the bending / tri (n-butyXj-päosphin / ^ niekoläioarbonyl be on. durcL known manner blurring toi solutions Niejielcarbonyl with solutions dos Ldg ^ r'üiiii Xm VerUält ^ ia 1 t ί odor 1: 2 produced at room temperature, with an erosion of one or two carbon monocyte groups taking place. The rate of the reaction is recognized by the flux of the carbon monocyte development after the mixture of carbon monocytes has been left to stand overnight in connection with a Blaeenis counter The solvent is driven off in a rotating evaporator and the product remains in quantitative yield »

Aorolein and acrylonitrile are preventative before use distilled and stabilized with hydroquinone. Before heating to reflux temperature, use the atmospheric Oxygen by flushing out the reaction vessel old nitrogen removed. The amount of nickel carbonyl used is in the range from 0.05 to 0.10 mol, that of the ligand in the range τοη 0.06 to 0.20 mol; on every jail

-H-

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however, the ratio of hiokeloarbonyl sun ligands is 1: 2. When heated to reflux temperature, eioh develops Carbon monoxide, which can be measured to determine whether the reaction proceeded quantitatively. The complex compounds form in crystalline form. They are filtered off, washed with a solvent such as methanol and ether and placed under nitrogen, e.g. on a glass frit filter, getrookne ^.

Example 4

Paa X) imere is produced in larger quantities by the method of Example 3 and by. Vacuum distillation obtained. It has the following properties: Molecular weight by maneuver spectrography 106? Bp ^^ »103 ° C; Pp «* -9» 57 ° 0 |

n ^ _M 1.4 ^ 453; ΐψ «0.9756.

AnaJ.ys®

Found "C" 68.06 ^ i H "5.74 i \ H" 26.36 i>. Calculated: C = 67.90 fa H - 5.70 fa N - 26.40 L.

The infrared absorption spectrum shows two Kitrilinaxlaa, a conjugated thereof, and an unsaturated methylene bond conjugated with a nitrile group * NMR spectroscopy shows the Absence of methyl groups. The sample is hydrolyzed to the known 2-methyleneglutaric acid (mp * 132 ° C). The spectroscopyohe Analysis of this compound shows the presence of the

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Methylene group. Reduction with hydrogen produces 2-methylglutaric acid obtain; Mp * 76 ° C; no lowering of grades when mixed with an authentic sample of 2-methylglutaric acid; identical ultrared absorption spectrum, measured on a pill made of potassium bromide. The IMR spectroscopes sessends the presence of a methyl group. The original dinere is therefore 2-methyleneglutaronitrile

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Eg 15

Acrylonitrile is made using various catalysts and solvent dimerized according to the following procedure: The acrylonitrile and the solvent are mixed in a brownish bottle, the bottle is flushed with nitrogen, and then the catalyst is introduced, taking 1 ml of a solution of the catalyst in benzene can be used on 50 ml of the acrylonitrile solution. The mixture stayed in after being briefly stirred initially stand in a water bath. After 24 hours, the solution was then subjected to injection phase chromatography for the content of 2-methylene glutaric acid nitrile and acrylonitrile analyzed The Difference between the sum of these two levels and the initial one Acylnitrile helped the formation of polymeric product attributed to. The catalysts and solvents used j as? the legal conditions and results are in the compiled in the following table.

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Solvent (vol .- {6; host acrylonitrile) TrleycXohexylphoaphlri Catalytic concentrate. (g / l00 ml) Temperature ί C) Conversion (g / g catalyst) Yield (g / g catalyst)

2-methylenglutaronitrile polymers!

Tri (R-

-Thoaphin

Catalog concentration. (g / l00 ml) temperature ( C)
Conversion (g / g catalyst) Auabeut "Tg / g catalyst) to 2-methyleneglutaronitrile polymers"

Trlcyolopentylphoaphin Katäl.-Concentrate, (g / 100 ml) Temperature '(C) Conversion (g / g catalyst) Yield (g / g catalyst) of 2-methylenglutaronitrile polymer

Tricyoloheptylphosphine Catal. Concentrate. (g / l00 ml) Temperature (C) Conversion (g / g catalyst) Yield (g / g catalyst)

2-methyleneglutaronitrile polymer

Benzene p-xylene oil acetone t-butanol t-butanol benzene (7b Vol. #) (7Ö Vol.Ji) (70 Vol. ^) (78 Vol. *) {15 Vol.Jt; j (70

Benzol * ^r ol. %

■ (55

0.2 25

36

24 12

0.2

25 7Ö

51 27

0.046
25th
193 0.048
25th
151 0 C6
2i>
257 0.048
25th
112 139
54 103
47 100
12th 0.35
25th
12th 9.0
3

_jsungsraittel (Vol.-Ji; remainder aor "aitrile)

go

00
O
CD
OO

Benzene p-xyloI acetone t-butanol t-butanol benzene

(78 Vol.Jg) (7b Vol.Sfi) (70 Vol.Ji) (78 Vol. %) (15 Vol. #) :( 7G ^ o

Bensol (55 Vol. #)

TricyolooctylphoBphln catalog concentrate (C)

Temperature {C) Conversion (g / g catalyst) Yield (g / g catalyst)

2-methylenglutaric acid nitrll

Polymer

IdI- (n-batyl) -phoai

_a . n

Catal. Concentrate. (g / iOOml) Temperature (C) Conversion (g / g catalyst) Yield (g / g catalyst)

2-Nethylene Glutaric Acid Trile

Polymer

Phenyl lloyolohexylphosphine

Katal.-Kencentral.lg / l00 ml)

Temperature (C) Conversion (g / g catalyst) Yield (g / g catalyst)

2-Methylengltttarsäurenitrll

Polymer

Phenyldl- (n-ootyl) -

there

(g / 100 ml)

Catal. Concentrate
Temperature (C) conversion (g / g catalyst) Yield (g / g catalyst) of 2-methyleneglutarsaurenitrile polymer

0.067

VJI

CC

0.186

25 25

21 4

0.048 25

68

Claims (1)

Claims 1 * Process for the division of dimers from acrylonitrile compounds, marked with it! that Aorylsäurenitril "Methacrylsäurenitriltfci'henylacrylsäurenitril, Äthylacryleüurenitril, cinnamonitrile,? umaraäurenitril or 2-cyano-3-methylbutene" 2 in a solvent at temperatures of about -40 to ⁰ 4-100 C in the presence of a trialkyl, triaryl, or mixed tertiary Alkylarylphosphina or a zero-valent nickel additive compound of the general formula (R) _n Ni (CO) ₄ ^ _n , in which S denotes the heat of a trialkyl-, triaryl or mixed tertiary alkylarylphosphine and η is 1 or 2, are dimerized as a catalyst _e where the catalyst is used in a narrow range of about 0.1 to 10 parts by weight of the acrylonitrile compound ο 2 «Yerfahren according to claim 1, characterized in that in addition an alcohol is used as an auxiliary catalyst, 3ο method according to Anepruoh 2, characterized in that ale ¹ ΐ Alcohol isopropanol or tertο Buty! Alcohol use ^, will .. "■. · 20« «0981 1/1 127 A-53108 Process according to claim 1 to 3 »characterized in that tri ~ (n ~ octyl) -phoephine _f tri- (n-butyl) -pho8phine, di- (H-Oe ty I) -phenyl phosphine or tri- ( n-butyl) -phoephine-Hiekeldicarbonyl is used o BATH ORIGINAL - 21 - ■ 80981 1/1127