SU670215A3 - Method of producing mixture of 1,4-dicyanogen butene cys-transisomers - Google Patents

Description

may be soluble or insoluble, better soluble. Insoluble catalysts should be dispersed in the reaction mixture in finely divided form. When working in the vapor phase, it is desirable to apply the catalyst to a suitable carrier, for example coke, charcoal, aluminosilicates, silica gel, etc. / Excess amount of hydrogen cyanide but compared to stoichiometrically. Provides the greatest degree of conversion of 2-methylene glutaronitrile, resulting in The amount of 2-methyleneglutane ronitrile to be recycled is minimized. Unreacted hydrogen cyanide can be reused in the process. The main components of the obtained product are cis and trans-1,4-dicyanbutenes-1. Together with them, 77 d "c-1,4-dianbutenes-2" are also obtained. All of these compounds are feedstock for the preparation of adipynitrile. Example I. Dehydrocyanation 1,2, 4-tricyanbutane. A vertical stainless steel tube with a diameter of 6.35 mm and a length of 508.0 mm, provided with an inlet section in the upper part and an outlet section in the lower part, is heated in an electric furnace. A layer of stainless steel fibers is placed on the bottom of the tube, onto which the catalyst is dehydrated (5 ml of activated carbon, on which surface 15% by weight of potassium cyanide is applied). A layer of 152.4 mm high glass beads is placed on top of the catalyst bed. A thermocouple is used to measure the temperature in the reaction zone. Slowly melted 1,2,4-tricyanbutane 1,2,4-Tricyanbutane is fed into the upper part of the tube by passing a carrier gas — nitrogen — in contact with hot glass beads into pairs that are exposed to the reaction temperature. The reaction products condensed in a glass condenser after passing through the outlet section of the tube are collected in collections cooled by a mixture of solid carbon dioxide (dry ice) with acetone. As a result of the process, produced at a temperature of 350, a feed rate of 0.25 mol of 1,2,4-tricyanbutane in 1 h and 0.75 mol of nitrogen in 1 h, about 25% of tricyanbutane reacted. According to the gas-liquid chromatographic analysis, the resulting reaction product has the following composition: 55 wt.% 1,4-dicyan-1-butene (DCB) (trans-cis-), 5 wt.% 1,4-dician2-butene (trans-, cis-) and 40% by weight of 2-methyleneglutaronitrile. The yield of the ICP is 59% (3.9 g / h). PRI mme R 2. A. Dimeriz / di acrylonitrile. A mixture of 160 g of acrylonitrile, 10 g of hydroquinone and 600 ml of dioxane is heated under reflux at a pressure of 1 atm in an atmosphere of previously purified argon. A solution containing 6 g of tricyclohexylphosphine in 200 ml of dioxane is gradually added over 20 minutes. The mixture is heated for an additional 20 minutes under refluxing by a refrigerator for an additional 20 minutes, then using a 2.54 cm diameter column containing 20 plates, 90 g of 2-methyleneglutaronitrile (purity 95%) are obtained in the form of a distillation boiling in the range of 138-142 ° With a residual pressure of 16 mm Hg. Art. B. Preparation of 1,2,4-tricyanbutane .. In a glass bottle, for carrying out the reaction, equipped with a magnetic stirrer, a reflux condenser and a gas supply device, 64 g of 2-methylene glutaronitrile, 60 ml of propionitrile and 1 g of triethylamine are placed. The mixture is cooled to. -80 ° C, after which 16.2 g (0.6 mol) of hydrogen cyanide are fed to the cooled mixture. The resulting mixture is left to stand until its temperature rises to room temperature, then it is re-stirred for 48 hours at 25 ° C. The reaction mixture is analyzed by gas-liquid chromatography. After completion of the hydrocyanation of 2-methylene glutaronitrile, the solvent (propionitrile), catalyst (triethylamine) and unreacted 2-methylene 1-lutarinitrile are separated from the reaction product by single distillation under reduced pressure. 69 g of 1,2,4-tricyanbutane are obtained. It is further purified by treatment with activated carbon and crystallization from absolute ethanol. Get 60 g of pure white crystalline substance, so pl. 53-54 ° C. IR spectroscopy shows that the product is identical to 1,2,4-tricyanbutane, obtained by a known method. B. Dehydrocyanation of 1,2,4-tricyanbutane in the liquid phase. 100 g of a mixture (50:50 suspension) of 1,2,4-tricyanbutane (example 1) and propionitrile are slowly (approximately at a rate of I g / min) 20 g of cyano-sodium in 50 ml of eicosane in a 50 ml mixture is added to the vigorously stirred flask and heated to 300 ± 10 ° C. The flask in which the reaction is carried out is equipped with a small Vigre column as a reflux condenser connected to a water cooled condenser and a product collector cooled by a mixture of solid carbon dioxide and acetone. During the reaction, a slow argon current is passed through the reactor, the column reflux condenser and the condensation system. A stoichiometric mixture of dehydrocyanation products (1,4-dicyanbutenes and 2-methyleneglutaronitrile) with hydrogen truncate is obtained. The yield of 45% .;

According to gas-liquid chromatography, the product has the following composition; 60 wt.% 1,4-dtsian-1-6 outen (face-, cis-), 5 wt.%

1,4-dicyan-2-butene (trans-, cis-) to 35% by weight of 2-methyleneglutaronitrile. The reaction product in the form of a mixture is subjected to fractionated distillation on a column having 20 plates, while four fractions are selected: the first at 25-35 ° C and a pressure of 1 at (hydrogen cyanide); the second at 35-100 ° C and a pressure of 1 atm (propionitrile as a solvent), the third at 138-142 ° C and a residual pressure of 16 mm Hg. st, (2-methylenephosphonate) and fourth at 142-170 ° C and a residual pressure of 16 mm RT. Art. (1,4-dicyanbutenes). Yield 30% (11.9 g).

Hydrogen cyanide, obtained in the form of the first fraction, and 2-methylene glutaronitrile, obtained in the form of the fourth fraction, are converted into 1,2, 4-tricyanbutane using triethylamine (TEA) as a catalyst in accordance with the procedure described in Example 1. Thus obtained by tricyanbutane, in physical and chemical terms, is identical to 1,2,4-tricyanbutane obtained from 2-methyleneglutaronitrile. Example 3. Preparation of 1,2,4-tricyanbutane.

A mixture consisting of 2.5 g of 2-methyleneglutaronitrile (2-MGN), 1.27 g of a 50% aqueous solution of hydrocyanic acid in propionitrile, and 0.025 g of tri-n-butylphosphine (TBP) is placed in a thick-walled glass ampoule 30 ml, which is sealed in an argon atmosphere, corresponds to the molar ratio of hydrogen cyanide: 2-methklenglutaronitrile 1: 1 in the presence of 1 wt.% Of the catalyst. The ampoule is placed in a water bath having a temperature of 50 ° C for 2 hours, after which the ampoule is cooled and opened, 0.2 ml acetic acid is added to the contents of the ampoule. catalyst deactivation. After that, the liquid reaction mixture is analyzed by titration and gas-liquid chromatography. The hydrogen cyanide conversion was 93.3%, and the methylene glutarointryl conversion was 99.6%, essentially all hydrogen cyanide was converted to 1,2,4-tricyanbutene. 1,2,4-Tritzianbuten is converted into a mixture of cis, trans-. Isomers of 1,4-dicyanbuten by dehydrocyanation, the yield is close to the yield obtained in example 1.

Example 4. A series of experiments were carried out using various catalysts and propionitrile as a solvent according to a procedure similar to that shown in Example 3. In each case, the starting materials were placed in thick-walled glass reactors, sealed in argon atmosphere and heated at 50 ° C B for 2 hours. Then the reactors are cooled, and their contents are analyzed by titration and gas chromatography methods to determine the conversion of hydrogen cyanide and 2-methylene glutaronitrile. The coincidence of the data characterizing the degree of conversion indicates that in each case, severity with respect to 1,2,4-tricyanbutane is about 95% or more. The resulting 1,2,4-tricyanbutane is converted into DCC by dehydrocyanation, the yield is that DCD is close to the result obtained in Example 1. The results of the experiment are shown in Table. one.

Claims (3)

Table 1 At 30 ° C. The reaction time is 1 hour. Basic, ion-exchange, see Example 5. A 1-liter autoclave loaded with 500 cm of 1,2,4-tricyanbutane is purged with nitrogen and heated to 60 ° C. Then liquid 2-methylene glutaronitrile is fed to the reactor at a rate of 108 g / h. The 2-methylene glutaronitrile supplied contains 0.33% by weight of tri-n-butylphosphine as a catalyst. Hydrogen cyanide gas is bubbled into the autoclave at a rate of 28.9 g / h. The constant liquid level in the reactor is maintained by withdrawing liquid at a rate of about 150. The process is carried out for 4 hours. During this time, the reaction conditions stabilize, which is noted by the stability of the analytical indicators of the liquid phase leaving the reactor. A sample of the effluent is collected for 1 hour. The composition of the sample: 92% by weight of tricyanbutane and 3.9% by weight of 2-methylglutaronitrile. This corresponds to a 95% conversion of the 2-methyleneglutaronitrile supplied and a degree of selective action with respect to 1,2,4-tricyanbutane 98%. 1,2,4-Tricyanbutane is converted to 1,4-dicyanbuten by dehydrocyanation, the yield is approximately equal to the yield in Example 1. Example 6. Dehydrocyanation of 1,2,4-three cyanbutane in a static reactor. 40 g of 1,2,4-tricyanb-tan (TCB) are placed in a 100 ml glass reactor equipped with a stirrer and heated while moving at 240 ° C. Then 0.013 g of lithium acetate is added as a catalyst. Argon gas is passed through the liquid reaction mixture at a rate of 100 ml / min. Argon is passed at the same rate through a 250 ml flask containing 125 ml of stirred 0.2 M ammonia solution. In this flask, hydrogen cyanide is absorbed, which is the product of the reaction. The solution is titrated with 1N. silver nitrate. During the reaction, four samples of the reaction mixture (2 ml each) are taken and analyzed for the content of 1,4-dicyanbugenes (1,4-DTSB) and 2-methylene glutaronitrile (2-MGN). The conversion is calculated based on the amount hydrogen cyanide, determined by analysis. The results are shown in the table, they show the relationship between the concentration of 1,4-dic1-anbutenes + 2-methylene glutaronitrile and the selectivity of the reaction. Table 2 TCB (mol) 1,4-DCB + 2-MGN formed (mol) TCB reacted (mol) Example 7. The procedure of Example 4 was repeated, but adiponitrile was used as the solvent and lithium hydroxide as the catalyst. 4.9 g of 1,2,4-triacianbutane and 39 g of adiponitrile are placed in the reactor and heated to 250 ° C. To ensure the onset of dehydrocyanation, 0.002 g of lithium oxide hydrate is added as a catalyst. The conversion of 1,2,4-tricyanbutane is followed by analyzing the reaction mixture by gas-liquid chromatography (conversion I) and the hydrogen cyanide content in the composition of the exhaust gas (conversion II) .. The results are shown in Table. 3. T. bl. Ct TSB (mol), 4-DBTs + 1-MH-formation (mol) ..X1V / V CBC reacted (mol) Example 8. Continuous dehydrocyanation of 1,2,4-tricyanbutium. Continuous dehydrocyanation of 1,2,4-tricyanbutane is carried out using a glass unit with a rotating layer of a monomolecular liquid, equipped with a jacket. The internal scientific research institute condenser is cooled circulating in doy, having a temperature of 25 ° С, and the external workpiece is heated with dimethyl phthalate vapor, having a temperature of 284 ° С. A vacuum of 45 ± 5 mm Hg is created in the film reactor. Art. and preheated argon in the amount of 300 ml / min is passed through the bottom to the reactor. The reaction products leaving the upper part of the reactor are captured at the temperature of a mixture of solid carbon dioxide with acetone (-80 ° C). 300 g / h of 1,2,4-tricyanbutane mixed with 3 g / h of lithium tetarate preheated to 150 ° C are fed to the reactor. Products condensed during the reaction are collected from the external condenser, as well as from a trap cooled with dry ice. Unrecovered 1,2,4-trish1anbutan ,. which did not evaporate during the reaction, is collected as a residue, together with some by-products and a catalyst. The reaction time is 1 hour. The combined quantities of products collected are collected from the upper part of the reactor and from the trap. The products have the following composition: 7.3 g of hydrogen cyanide, 9.4 g of 2-methigl glutaronitrile, 9.1 g of 1,4-dicyanyl butene-1 (grins), 9.1 g of 1,4-dicyanbuten-1 (cis -) and 235 g of 1,2,4-tricyanbutane. According to the analysis, the residue has the following composition: 1.1 g of by-product, 3 g of catalyst, 28.8 g of 1.7 4 -T11 cyanbutane and less than 1 mol. % 2-methylene glycol; 1 po1stryl and 1,4-dicyanbutenes. . Based on the data obtained, the conversion of 1,2,4-tritsnanbutan (12%) and the selectivity of the dehydrocyanating process (96) are calculated. The yield of securities of 11.5% (18.2 g). Example 9. The procedure described in example 6 is repeated at a pressure of 740 mm Hg. At this pressure, a reduced amount of boil-off products is obtained as compared with example 6. The relative concentration of 2-methylene glutaronitrile and 1,4-dicyanbutenes in the residue is according to the analysis of 5 mol.%. Selectivity of the reaction, calculation at 13%. Versions of 1,2,4-tricyanbutane, 507 °. The output of the securities market + 2-MGN 6.5%. PRI me R 10. Continuous dehydrocyanation. 70 g / h of 1,2,4-tricyanbutane and 3 g / h of lithium etearate, preheated to 150 ° C, are fed continuously to a stainless steel reactor (evaporator), operating according to the principle of a falling film. The inner diameter of the reactor is 50.8 mm, the evaporation area is 322.6 m. The upper part of the reactor is directly connected to a fractionation column, having about 5 theoretical plates, the column has a device for refluxing, located in the upper part and corresponding to a vacuum system, ensuring it has a residual pressure of 45 mm Hg. Art. The reactor is heated with vanilla salt, the temperature is maintained at 285 ° C ± 3 ° C. 300 ml / min (at 25 ° C) of argon, preheated to 285 ° C from the bottom, is passed through the reactor in countercurrent to the falling reaction mixture. During the test, the product is continuously sampled at a reflux ratio of 1: 4. The unreacted 1,2-, 4-tricyanbutane together with the catalyst, high-boiling by-products and some of the main product are withdrawn from the bottom of the reactor. After 1 hour of reaction, the following results are obtained: go) the juvenile product contains 26 g of 2-methylenphenyluthenyl and 1,4-dicyanbutenes, 3 g of 1,2,4-trisch | anbutane and 7.9 g of w-1anns1O) of hydrogen the product taken from the bottom of the reactor contains 30 g: 1,2,4-tricyanbutane, 3 g of lithium etearate, 2.5 g of high-boiling products, 0.6 g of 2-methyleneglutaronitrile and 1,4-dicyanbutenes in the amount, corresponding relative endtitash {n 2.5 mol.%. The calculated conversion value of 1.2,4-three y1anbutan is 55.7%. The specific reaction selectivity is 92%. B: the course of the cerebral palsy-i-2 MGN 51.2%. 11 The top product was fractionated with a 40-plate column and 3 g of unreacted 2-methynglutaronitrile was isolated as a fraction boiling at 131--33 ° C / 10 mm Hg. Art. The 2-methylenegluranitrile is again converted to 1,2,4-tricyanbutane by reaction with hydrogen cyanide (see Example 2B). Claim I. Investigation of a mixture of cis-, trans-neomers of 1,4-dicyanbuten, in a few tons, so that, in order to increase the selective process, 2-methylene glutonitripe is reacted with cyanide with hydrogen at 25–250 ° C and a molar ratio of the reagents of 12 1: 2–2: 1, followed by dehydration with the obtained 1,2,4-trIl-11butane in the presence of a catalyst at 250–450 ° C. 2. The method according to claim 1, wherein tl and h and y and so, as a catalyst using salts of aliphatic carboxylic acids, salts or hydroxides of alkali metals or trialkylamines, or trialkylphosphine, taken in an amount of 0.01 -3 wt.%. 3. The method according to paragraphs. 1 and 2, that is, that the process is carried out in an organic solvent medium. Sources of information taken into account in the examination of j US Patent N 3225083, cl. 260-465, 1965.