269results about "Preparation by carboxylic acid amide dehydration" patented technology

The invention provides a method and device for preparing 6-amino-capronitrile from caprolactam by adopting a liquid phase method. In the method for preparing the 6-amino-capronitrile, the caprolactamis taken as a raw material; the method for preparing the 6-amino-capronitrile comprises the following step: S1: mixing the caprolactam, an organic solvent and a catalyst at a certain mass ratio, so asto obtain a mixed solution, adding the mixed solution into a reaction kettle and stirring and heating the mixed solution; S2: when the mixed solution in step S1 reaches certain temperature, introducing ammonia gas into the mixed solution for a reaction; S3, after the reaction in step S2 is ended, rectifying and purifying a reaction product, so as to obtain pure 6-amino-capronitrile. In the methodfor preparing the 6-amino-capronitrile, the caprolactam is taken as the raw material, the reaction conversion rate is comparatively high, and the preparation process is simple.

The invention discloses an aromatic diamine containing o-phthalonitrile side group. The structure formula of the aromatic diamine is shown as the right formula. The invention also discloses a method for preparing the aromatic diamine and polyimide and daiamid which are prepared by taking the aromatic diamine containing the o-phthalonitrile side group as one of raw materials. The o-phthalonitrile side group in the aromatic diamine is positioned on the side chain, thereby adjusting the degree of crosslinking with adjusting the polymer molecular weight and widening the application of the polyimide and the daiamid in a thick-wall composite material or a composite material element with a complicated shape and the fields of membrane material and fiber.

The invention discloses a preparation method of perfluoronitrile. The preparation method comprises the following steps: a, performing a gas-phase addition reaction on perfluoroolefin R1R2C=CR3R4 and carbonyl fluoride to obtain acyl fluoride R1R2(COF)C-CFR3R4 (R1, R2, R3 and R4 have a general formula of a -CnF2n+1 group and n is a nonnegative integer set); b, aminating and dehydrating the acyl fluoride R1R2(COF)C-CFR3R4, acyl fluoride and alkali metal amide or an amine compound R-NH2 (R is lithium, sodium, potassium, rubidium, cesium or a -CmH2m+1 group and m is a nonnegative integer set) to obtain the perfluoronitrile R1R2(CN)C-CFR3R4. By the preparation method, a reaction route is short, the perfluoroolefin and the carbonyl fluoride are easy to obtain and low in price, the overall yield of the perfluoronitrile is high and the route is easy to industrialize.

The invention provides a separation method of an ammoniation dehydration product of caprolactam and a synthesis method of hexamethylenediamine. The separation method comprises the following steps: S1,carrying out ammoniation and dehydration reaction on caprolactam and ammonia gas to obtain a product system; S2, carrying out primary condensation treatment on the product system to obtain a caprolactam-containing fraction and a primary gas-phase component; and S3, carrying out secondary condensation treatment on the primary gas-phase component to obtain a 6-aminocapronitrile fraction and a secondary gas-phase component, wherein the temperature of the secondary condensation treatment is lower than that of the primary condensation treatment. According to the separation method, the product system obtained through the reaction is directly subjected to condensation treatment, secondary heating is not needed, continuous operation of the reaction and product separation can be achieved, waste heat can be fully utilized, the separation efficiency is high, the production intensity is high, the separation energy consumption is low, and therefore the whole process is more energy-saving.

Bio-based materials, e.g., epoxide starting material, a beta-lactone starting material and/or a beta-hydroxy amide starting material, may be used as feedstocks in processes for making and using acrylonitrile and acrylonitrile derivatives to produce, among other products, carbon fibers and carbon black.

The invention discloses a perfluoro nitrile preparation method. The perfluoro nitrile preparation method comprises the following steps: an addition reaction is performed on perfluoroolefine R1R2C=CR3R4 and carbonyl fluoride to obtain acyl fluoride R1R2(COF)C-CFR3R4(the general formula of R1,R2,R3 and R4 is -CnF(2n+1) group, and n is a nonnegative integer set); b, performing a reaction on acyl fluoride R1R2(COF)C-CFR3R4, acyl fluoride and an alkali metal amide or an amino compound R-NH2(R is Li, Na, K, Rb, Cs or -CmH(2m+1) group, and m is a nonnegative integer set) to obtain amide R1R2(CONH2)C-CFR3R4; and c, performing a dehydration reaction on amide R1R2(CONH2)C-CFR3R4 to obtain perfluoro nitrile R1R2(CN)C-CFR3R4. The perfluoro nitrile preparation method has a short reaction path, can easily obtain perfluoroolefine and carbonyl fluoride, is low in cost and high in overall yield of perfluoro nitrile, and the reaction path is easy to industrialize.

Process for preparing nitriles by reacting N-alkylcarboxamides (RCO—NHR¹) or ammonium salts of carboxylic acids (RCOO—NH₃R¹⁺) or carboxylic acids in the presence of alkylamines or ammonium salts (RCOOH+NH²R¹, RCOOH+NH₃R¹⁺), respectively, R being an arbitrarily substituted linear or branched C₁-C₁₂-alkyl radical, a C₃-C₁₂ cycloalkyl radical or an alkenyl, alkynyl or aryl or heteroaryl radical and R¹ being an arbitrary substituted, linear or branched C₂-C₁ alkyl radical, a C₃-C₁₂ cycloalkyl radical or an alkenyl or alkynyl radical, with phosphonic anhydrides in the presence of an optional base in an organic solvent at a temperature in the range from −30 to 180° C. In advantageous embodiments, the phosphonic anhydride is a 2,4,6-substituted 1,3,5,2,4,6-trioxatriphosphinane 2,4,6-trioxide of the formula (I)

2-Hydroxybenzonitrile is prepared by passing 2-hydroxybenzamide in the gas phase over a heterogeneous catalyst thereby effecting dehydration of the 2-hydroxybenzamide to produce 2-hydroxybenzonitrile.

The invention provides a method for producing a hexamethylenediamine key intermediate 6-aminocapronitrile by a continuous gas-phase two-step method. The method comprises the following steps: S1, mixing caprolactam and water in a gas phase state to carry out continuous hydrolysis or mixing caprolactam and ammonia water in a gas phase state to carry out continuous hydrolysis ammoniation reaction toobtain a first product system containing 6-aminocaproic acid, 6-aminocaproic acid ammonium salt and/or 6-aminocaproamide; and S2, carrying out continuous gas-phase catalytic ammoniation and dehydration reaction on the first product system and ammonia gas to obtain a second product system containing 6-aminocapronitrile. According to the patent of the invention, the problem that water generated by reaction in a one-step process promotes polymerization reaction of the raw material caprolactam is reduced from the source, and the selectivity of aminocapronitrile is improved; and the problems of catalyst deactivation and pressure drop rise caused by polymerization and coking of caprolactam in the reactor are effectively reduced, the stability of the device is improved, and the service life of the catalyst is prolonged.

The invention discloses a method for preparing perfluorinated nitrile through gas phase catalysis. The method comprises the following steps: a, in the absence of a catalyst, enabling acyl fluoride R1COF or perfluor substituted ethylene oxide Cyclo-CF2-CR2R3-O- to perform a gas phase amination reaction with an ammonia gas or a primary amine compound, to obtain amide of which a general formula is R1CONH2 or CR2R3FCONH2, wherein general formulas of R1, R2 and R3 are CnF[2n+1], CxF[2x+1], and CyF[2y+1], wherein x and y are non-negative integer sets, x+y=n, and n is a positive integer set; and b, in the presence of the catalyst, dehydrating the amide R1CONH2, to obtain the perfluorinated nitrile R1CN. The method is short in reaction route, and the perfluor substituted ethylene oxide or the acylfluoride is easily obtained. A total yield of the perfluorinated nitrile is high, and the route is easy for continuous industrialization.

The invention provides a method for preparing terephthalic benzonitrile. The method comprises the steps of taking biphenyl and trichloro-acetic chloride as raw materials and preparing theterephthalic benzonitrile through acylation, aminolysis and dehydration reaction. The method overcomes the disadvantages that the prior art is expensive in raw materials, high in intermediate toxicity, harsh in reaction conditions, low in reaction yield, poor in purity and the like, provides a terephthalic benzonitrile synthesizing process which is easy to industrialize, convenient to operate, high in yield and high in product purity, and provides a key raw material intermediate for producing the pigment red 264 with bright color and high quality.

The invention relates to a manufacturing method of nitrile. Compared with the prior art, the manufacturing method has the characteristics of significantly reduced using amount of an ammonia source, low environmental pressure, low energy consumption, low production cost, high purity and yield of a nitrile product and the like, and nitrile with a more complex structure can be obtained. The invention also relates to a method for manufacturing corresponding amine from nitrile.

The invention relates to a malononitrile synthesis method and belongs to the technical field of malononitrile synthesis. The malononitrile synthesis method comprises the following steps of 1, adding methanol or ethanol into a reactor, feeding ammonia gas into the reactor at a temperature of -20 to 50 DEG C, dropwisely adding methyl cyanoacetate or ethyl cyanoacetate into the reactor at a temperature of -20 to 50 DEG C, after dropwise addition, carrying out heat-preservation stirring, carrying out reduced pressure degasification until a temperature is reduced to below -10 DEG C and carrying out filtration and drying to obtain cyanoacetamide, and 2, mixing a dehydrant, a catalyst, cyanoacetamide and a solvent, heating the mixture for a reflux reaction lasting for 6h, carrying out cooling and filtration, removing the solvent to obtain a crude product, and carrying out reduced pressure rectification to obtain a malononitrile product. The preparation method has less reaction processes, can be operated simply, has a high yield and good product purity, utilizes cheap and easily available raw materials, greatly reduces a production cost, is free of an adsorbent, has a less phosphorous oxychloride use amount, greatly reduces three wastes, realizes easy recovery and recycle of the solvent, is suitable for industrial production and solves the problems of the existing a malononitrile synthesis method.

The invention discloses a synthesis method of perfluoroisobutyronitrile, comprising the following steps of: (1) carrying out a reaction between oxalyl chloride monoester and fluoride salt in a solventto obtain oxalyl fluoride monoester; (2) carrying out a reaction between oxalyl fluoride monoester and hexafluoropropylene in a solvent by taking fluoride salt as a catalyst to prepare heptafluoro-2-carbonyl-3-methylbutyrate; (3) carrying out catalytic decarbonylation on heptafluoro-2-carbonyl-3-methylbutyrate in a solvent through cesium fluoride, so as to obtain heptafluoroisobutyrate; and (4) carrying out a reaction between heptafluoroisobutyrate and ammonia, and dehydrating to obtain perfluoroisobutyronitrile. The synthetic method has the advantages of easily available raw materials, mildreaction conditions, high raw material conversion rate and product yield, safe and simple process operation, and easy realization of industrial production.

The invention provides a method for preparing a hexamethylenediamine key intermediate 6-aminocapronitrile by a two-step method. The method comprises the following steps: step S1, in a first reactor, after caprolactam is subjected to a hydrolysis reaction in an aqueous solution, introducing first hot ammonia gas into the first reactor to obtain an aminocaproamide crude product, the temperature of the first hot ammonia gas being 150-250 DEG C; S2, performing catalytic dehydration on the aminocaproamide crude product and second hot ammonia gas in a second reactor to obtain aminocapronitrile, wherein the temperature of the second hot ammonia gas ranges from 200 DEG C to 300 DEG C. According to the invention, the polymerization of the hydrolysate is effectively controlled in the step S1 so thatpolymerization of the polymer on the surface of the catalyst when the aminocaproamide crude product participates in the catalytic dehydration reaction in the step S2 is effectively relieved, coking of the catalyst is avoided, the service life of the catalyst is prolonged, and then lasting high-conversion-rate and high-selectivity preparation of 6-aminocapronitrile from caprolactam is guaranteed.

The invention discloses a method and a device for producing hexamethylenediamine from caprolactam, ammonia gas and caprolactam are subjected to ammoniation and dehydration reaction under the action of a catalyst, and the obtained ammoniation and dehydration reaction product is subjected to three-stage condensation separation; caprolactam obtained through secondary condensation and 6-aminocapronitrile condensate are subjected to a hydrogenation reaction under the action of a catalyst, a mixture containing hexamethylenediamine and caprolactam obtained through the reaction is separated to obtain hexamethylenediamine, and water accounting for 5%-500% of the total weight of the condensate is added in the hydrogenation reaction process to serve as a hydrogenation reaction diluent. According to the method, the caprolactam aqueous solution is used as the 6-aminocapronitrile hydrogenation reaction diluent, ethanol does not need to be added as the diluent, and generation of by-products N-Et-HMD, BHT and tar is reduced. The ammoniation dehydration reaction liquid is not subjected to rectification separation, so that the energy consumption is reduced.

The invention relates to a preparation method of nitrile. Compared with the prior art, the preparation method has the characteristics of obvious reduction of the usage amount of ammonia sources, low environmental pressure, low energy consumption, low production cost, high purity and yields of nitrile products, and the like, and can be used for obtaining nitrile with a more complex structure. The invention also relates to a method for preparing corresponding amine with nitrile.