CN109280020B - Method for recovering hexanenitrile and cyclohexanone oxime from light impurity components of cyclohexanone oxime gas phase Beckmann rearrangement product - Google Patents
Method for recovering hexanenitrile and cyclohexanone oxime from light impurity components of cyclohexanone oxime gas phase Beckmann rearrangement product Download PDFInfo
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Abstract
The invention discloses a method for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime gas-phase Beckmann rearrangement product. The method comprises the following steps: 1) distilling and separating the light impurity components to obtain tower top fraction; 2) carrying out hydrogenation reaction on the tower top fraction to obtain a hydrogenation reaction product; 3) performing cyclohexanone ammoximation reaction on the hydrogenation reaction product to obtain an ammoximation reaction product; 4) distilling and separating the ammoximation reaction product to obtain capronitrile and cyclohexanone oxime; wherein the total content of hexanenitrile, cyclohexanone, 5-cyano-1-pentene in the overhead fraction is more than 90% of the total weight of the overhead fraction. The method provided by the invention can be used for obtaining high-purity hexanenitrile with high added value and cyclohexanone oxime which can be repeatedly used as a raw material for the cyclohexanone oxime gas-phase Beckmann rearrangement reaction, and can improve the economy of a gas-phase rearrangement process.
Description
Technical Field
The invention relates to the field of production of epsilon-caprolactam, in particular to a method for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime gas-phase Beckmann rearrangement product.
Background
Epsilon-caprolactam is one of important raw materials for synthetic fibers and synthetic resins, and is mainly used for the production of polyamide fibers (nylon 6), resins, films, and the like. In the early industrial production of epsilon-caprolactam, fuming sulfuric acid was used as catalyst and solvent, and liquid phase Beckmann rearrangement of cyclohexanone oxime was carried out. The process has the defects of equipment corrosion, environmental pollution, poor economic benefit and the like, and can generate a large amount of ammonium sulfate. The cyclohexanone oxime gas phase Beckmann rearrangement reaction on the all-silicon molecular sieve is a new process for realizing sulfur-free ammonification of epsilon-caprolactam, has the problems of no equipment corrosion, no environmental pollution and the like, and greatly simplifies the separation and purification of products, so the new process for the gas phase Beckmann rearrangement reaction without ammonium sulfate receives great attention.
However, in the case of the gas phase Beckmann rearrangement reaction of cyclohexanone oxime, since the reaction temperature is high, epsilon-caprolactam obtained contains various impurities up to about 4%. As is known, epsilon-caprolactam is a raw material for preparing polyamide, has high quality requirement on epsilon-caprolactam products used for preparing polyamide and further manufacturing synthetic fibers and synthetic resin, and impurities in the mu g/g grade can influence the subsequent polymerization reaction of the epsilon-caprolactam and are not easy to form filaments. Therefore, it is required to obtain high purity epsilon-caprolactam by various refining methods, and thus the high purity epsilon-caprolactam can be used for the production of synthetic fibers, synthetic resins, films and the like.
The existing refining method comprises the steps of recovering solvent, removing light impurities, removing heavy impurities, crystallizing, hydrogenating, dehydrating, distilling and the like, wherein low-boiling-point impurities accounting for about 2/3 of the total amount of the impurities can be separated in the step of removing the light impurities, the impurities are various and have different contents, and some high value-added impurities exist, and if the high value-added impurities can be recovered, the economic efficiency of the gas phase rearrangement process can be improved.
Disclosure of Invention
The invention aims to overcome one of the problems in the prior art and provides a method for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime gas phase Beckmann rearrangement product, so as to improve the economy of a gas phase rearrangement process.
In order to achieve the above object, in the present invention, there is provided a process for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime vapor phase beckmann rearrangement product, the process comprising: 1) distilling and separating the light impurity components to obtain tower top fraction; 2) carrying out hydrogenation reaction on the tower top fraction to obtain a hydrogenation reaction product; 3) performing cyclohexanone ammoximation reaction on the hydrogenation reaction product to obtain an ammoximation reaction product; 4) distilling and separating the ammoximation reaction product to obtain capronitrile and cyclohexanone oxime; wherein the total content of hexanenitrile, cyclohexanone, 5-cyano-1-pentene in the overhead fraction is more than 90% of the total weight of the overhead fraction.
In order to improve the economy of the gas phase Beckmann rearrangement reaction of cyclohexanone oxime, the inventors of the present invention conducted extensive studies on by-products produced in the step of purifying caprolactam, and found that various by-products having a lower boiling point than caprolactam, such as by-products having a higher content of capronitrile, cyclohexanone, 5-cyano-1-pentene, cyclohexenone, anilines, N-methylcaprolactam, etc., are enriched in the light impurity fraction discharged from the top of the light impurity removal step; wherein, the capronitrile is used as a basic chemical raw material and can be used for the organic synthesis of pesticides, the market price is about 30000 yuan/ton, and the economic value is much higher than that of caprolactam; it would be advantageous to improve the economics of the gas phase rearrangement process if the capronitrile could be recovered.
To this end, in the present invention, a process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product is provided. The method provided by the invention can be used for obtaining high-purity hexanenitrile with the purity of more than 95 percent, and the high-purity hexanenitrile can be directly sold as a basic raw material so as to improve the economic benefit and the economy of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction. Meanwhile, cyclohexanone oxime can be directly obtained by applying the method provided by the invention, and the cyclohexanone oxime can be repeatedly used as a raw material for the gas-phase Beckmann rearrangement reaction of the cyclohexanone oxime, so that the cost of the raw material for producing epsilon-caprolactam is reduced.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In order to improve the economy of the cyclohexanone oxime vapor phase Beckmann rearrangement reaction, the invention provides a method for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime vapor phase Beckmann rearrangement product, which comprises the following steps: 1) distilling and separating the light impurity components to obtain a fraction containing the top of the tower; 2) Carrying out hydrogenation reaction on the tower top fraction to obtain a hydrogenation reaction product; 3) performing cyclohexanone ammoximation reaction on the hydrogenation reaction product to obtain an ammoximation reaction product; 4) distilling and separating the ammoximation reaction product to obtain capronitrile and cyclohexanone oxime; wherein the total content of hexanenitrile, cyclohexanone, 5-cyano-1-pentene in the overhead fraction is more than 90%, preferably more than 95%, based on the total weight of the overhead fraction.
According to the present invention, there is provided a process wherein the light impurity components are distilled for the purpose of separating lower boiling point hexanenitrile, cyclohexanone, and 5-cyano-1-pentene from other components to obtain an overhead fraction having a total content of hexanenitrile, cyclohexanone, and 5-cyano-1-pentene of 90 wt% (preferably 95 wt%) or more. Wherein there may be no particular requirement for the conditions of the distillation. However, in order to obtain a faster and better separation effect, it is preferable that the step of distillative separation of the light impurity component is performed under reduced pressure, for example, a pressure of less than 100kPa, preferably less than 50kPa, more preferably less than 20kPa, and particularly preferably less than 10 kPa. In a preferred embodiment of the present invention, the conditions of the step of subjecting the light impurity component to distillation separation include: the pressure is 1-5kPa, and the distillation temperature is 70-120 ℃. Preferably, in the step of distilling and separating the light impurity component in actual operation, the reflux ratio of the top of the column is 1 to 10: 1.
according to the present invention, there is provided a process wherein the overhead fraction is subjected to hydrogenation for the purpose of converting the by-product 5-cyano-1-pentene into hexanenitrile, to increase the content of the target by-product hexanenitrile. The hydrogenation reaction in the present invention takes place in the presence of a hydrogenation catalyst, wherein the catalyst used may have no special requirements, and may be selected appropriately according to the aforementioned reaction requirements. The optional hydrogenation catalyst in the invention can be one or more selected from nickel hydrogenation catalyst, palladium hydrogenation catalyst and platinum hydrogenation catalyst. Preferably, the nickel-based hydrogenation catalyst is an amorphous nickel catalyst, and preferably, the weight ratio of the 5-cyano-1-pentene in the overhead fraction to the hydrogenation catalyst is 50-500: 1, preferably 100-: 1.
According to the method provided by the invention, the conditions of the hydrogenation reaction can be not particularly required, and the conditions are reasonably selected according to the reaction requirements, however, in order to improve the conversion rate of the 5-cyano-1-pentene, the conditions of the hydrogenation reaction preferably comprise: the temperature is 80-200 ℃, preferably 100-150 ℃, the pressure is 0.5-6.0MPa, more preferably 2.0-5.0MPa, and the time is 0.5-3h, preferably 1-2 h.
The process according to the invention is provided wherein the purpose of the cyclohexanone ammoximation reaction is, as its name implies, to promote the reaction of cyclohexanone to form cyclohexanone oxime. The method for performing cyclohexanone ammoximation reaction in the present invention can refer to the conventional reaction of cyclohexanone to form cyclohexanone oxime, for example, adding cyclohexanone (hydrogenation reaction product), ammoximation catalyst, ammonia and hydrogen peroxide to a solvent in a certain proportion to perform contact reaction under the condition of cyclohexanone ammoximation reaction.
According to the method provided by the invention, the ammoximation catalyst adopted in the cyclohexanone ammoximation reaction is a titanium silicalite molecular sieve catalyst; preferably, the average particle size of the ammoximation catalyst is 0.1-0.5 μm, preferably 0.1-0.3 μm; preferably, the ammoximation catalyst is used in an amount of 1 to 10%, preferably 2 to 8% by weight based on the total weight of the reaction slurry comprising the hydrogenation reaction product, ammonia, hydrogen peroxide and a solvent.
According to the method provided by the invention, the solvent adopted in the cyclohexanone ammoximation reaction can be one or more selected from water, benzene, toluene and lower alcohol, preferably methanol, ethanol, propanol, butanol or pentanol, and more preferably tertiary butanol; wherein the dosage of the solvent is 30-50% of the total weight of the reaction slurry.
According to the method provided by the invention, in the step of subjecting the hydrogenation reaction product to cyclohexanone ammoximation reaction, the molar ratio of hydrogen peroxide to cyclohexanone in the hydrogenation reaction product is 0.5-2.0: 1, the molar ratio of ammonia to cyclohexanone in the hydrogenation reaction product is 0.5-3: 1; the cyclohexanone ammoximation reaction conditions comprise: the reaction temperature is 50-80 ℃, and the reaction time is 0.5-3 h. In which ammonia is NH3It is suggested that ammonia may be fed as both gaseous and liquid ammonia, and is therefore referred to herein simply as ammonia.
According to the method provided by the invention, the ammoximation reaction product is subjected to distillation separation for separating the hexanenitrile and the cyclohexanone oxime. Wherein there may be no particular requirement for the conditions of the distillation. However, in order to obtain a faster and better separation effect, it is preferable that the step of subjecting the ammoximation reaction product to distillation separation is carried out under reduced pressure, the pressure being less than 100kPa, preferably less than 50kPa, more preferably less than 20kPa, particularly preferably 1 to 10kPa, and the distillation temperature being 80 to 130 ℃. Preferably, in the step of subjecting the ammoximation reaction product to distillation separation in actual practice, the overhead reflux ratio is from 1 to 10: 1.
according to the method provided by the invention, in order to obtain high-purity hexanenitrile and cyclohexanone oxime suitable for being used as a raw material, the light impurity components preferably comprise hexanenitrile, cyclohexanone, 5-cyano-1-pentene, aniline and homologues thereof and N-methyl caprolactam, and the content of the components accounts for more than 90 percent of the total weight of the light impurity components; more preferably, the light impurity mixture comprises, based on its total weight: 3-10% by weight of hexanenitrile, 5-15% by weight of cyclohexanone, 10-35% by weight of 5-cyano-1-pentene, 10-15% by weight of aniline and its homologues, 10-30% by weight of N-methylcaprolactam and 5-10% by weight of impurities.
According to the method, high-purity hexanenitrile with the purity of over 95 percent can be obtained, and the high-purity hexanenitrile can be directly sold as a basic raw material so as to improve the economic benefit and the economy of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction. Meanwhile, cyclohexanone oxime can be directly obtained by applying the method provided by the invention, and the cyclohexanone oxime (obtained by distillation and separation) can be repeatedly used as a raw material for the gas-phase Beckmann rearrangement reaction of the cyclohexanone oxime, so that the cost of the raw material for producing epsilon-caprolactam is reduced.
The advantageous effects of the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention will be further illustrated with reference to the following specific examples.
In the following examples and comparative examples, ammonia, hydrogen peroxide in an amount of 30 wt% and t-butanol in an amount of 90 wt% were all commercially available as chemically pure reagents, and the ammoximation catalyst used was an HTS-2 titanium silicalite molecular sieve available from Jian corporation of Hunan province and having a particle size distribution of 0.1 to 0.3. mu.m.
In the following examples and comparative examples, the employed cyclohexanone oxime gas phase beckmann rearrangement product light impurity component was analyzed by Agilent GC7890 gas chromatography (flame ionization detector (FID), Innowax capillary chromatography column, column length 30m), and the composition thereof included the following: 9.2% by weight of hexanenitrile, 12.4% by weight of cyclohexanone and 31.2% by weight of 5-cyano-1-pentene, 12.3% by weight of aniline homologues, 28.9% by weight of N-methylcaprolactam and 6% by weight of other impurities.
In the following examples and comparative examples, the reaction products of the respective steps were analyzed by gas chromatography (flame ionization detector (FID), OV-1 capillary column, column length 30m) of the Agilent GC7890 type.
Example 1
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) distilling 200.0g of light component raw material in a rectifying tower under reduced pressure, wherein the reduced pressure is 1.3kPa, and the reflux ratio of the tower top is 5: 1, the distillation temperature was 110 ℃ until substantially no distillate was distilled off, to obtain 93.2g of an overhead fraction. As a result of analyzing the overhead fraction by chromatography, it was found that the content of hexanenitrile was 16.8% by weight, the content of cyclohexanone was 22.6% by weight, the content of 5-cyano-1-pentene was 56.9% by weight and the content of the remaining impurities was 3.6% by weight.
2) The overhead fraction was placed in a 300ml hydrogenation vessel, to which was added 0.53g of amorphous nickel catalyst (SRNA-4, available from Jianchang, Hunan), heated to about 120 ℃ and then replaced with hydrogen for 5 times, the hydrogen pressure was maintained at 5MPa, the stirring rate was 300r/min, and the reaction was carried out for 2 hours. A hydrogenated reaction product was obtained, in which the content of hexanenitrile was 73.3% by weight, the content of cyclohexanone was 23.5% by weight, the residual content of 5-cyano-1-pentene was 0.3% by weight, and the content of the remaining impurities was 2.9% by weight, based on the total weight of the reaction product, as seen by chromatography analysis.
3) Putting 90.0g (containing 21.15g of cyclohexanone and 0.216mol) of the obtained hydrogenation reaction product into a reaction kettle, and adding a proper amount of the titanium silicalite molecular sieve, hydrogen peroxide, liquid ammonia and tert-butyl alcohol (wherein the molar ratio of the hydrogen peroxide to the cyclohexanone in the hydrogenation reaction product is 1.5: 1, the molar ratio of ammonia to cyclohexanone in the hydrogenation reaction product is 2.0: 1, the weight ratio of the titanium silicalite molecular sieve to the reaction slurry is 0.08: 1, the use amount of tertiary butanol is 40 wt% of the total weight of reaction slurry, and the reaction slurry comprises a hydrogenation reaction product, ammonia, hydrogen peroxide and a solvent); heating to about 70 ℃, stirring at a speed of 300r/min, and reacting for 1.5 hours to obtain a reaction product; the reaction product was distilled to remove excess ammonia and t-butanol as a solvent to obtain 83.5g of a bottom mixture, and the bottom mixture was analyzed by chromatography, wherein the content of hexanenitrile was 73.6 wt%, the content of cyclohexanone was 0.1 wt%, the content of cyclohexanone oxime was 23.4 wt%, and the content of the remaining impurities was 2.9 wt%.
4) Distilling 80.0g of the mixture at the bottom of the kettle in a rectifying tower under reduced pressure, wherein the pressure is 5kPa, the kettle temperature is lower than 130 ℃, and the reflux ratio at the top of the tower is 2:1, an overhead fraction (58.5g) and a pot bottom material (19.5g) were obtained. The content of hexanenitrile in the overhead fraction was 99.1% by weight, as determined by chromatography; the content of cyclohexanone oxime in the bottom material was 95.2% by weight.
Example 2
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) an overhead fraction was obtained in the same manner as in example 1.
2) The hydrogenation reaction was carried out in accordance with the corresponding method as in example 1, except that the temperature in the hydrogenation reaction was 100 ℃ and the pressure was 3MPa, to obtain a hydrogenation reaction product; as a result of analyzing the hydrogenation reaction product by chromatography, it was found that the content of hexanenitrile was 73.0% by weight, the content of cyclohexanone was 23.7% by weight, the content of 5-cyano-1-pentene residue was 0.5% by weight, and the content of the remaining impurities was 2.8% by weight.
3) The ammoximation reaction was carried out in accordance with the corresponding method as in example 1, except that the cyclohexanone ammoximation reaction was carried out under conditions such that the molar ratio of hydrogen peroxide to cyclohexanone in the product of the hydrogenation reaction was 1.2: 1, the molar ratio of ammonia to cyclohexanone in the hydrogenation reaction product is 1.0: 1, the weight ratio of the titanium silicalite molecular sieve to the reaction slurry is 0.06: 1; heating to about 60 ℃, stirring at a speed of 300r/min, and reacting for 2 hours to obtain a reaction product. Distilling the reaction product to remove excessive ammonia and solvent tert-butyl alcohol to obtain a kettle bottom mixture (ammoximation reaction product); the bottom mixture was analyzed by chromatography to find that the content of hexanenitrile was 73.2 wt%, the content of cyclohexanone was 0.2 wt%, the content of cyclohexanone oxime was 23.5 wt%, and the content of the remaining impurities was 3.1 wt%.
4) And (3) distilling the kettle bottom mixture (ammoximation reaction product) by using a rectifying tower under reduced pressure, wherein the pressure is 5kPa, the kettle temperature is lower than 130 ℃, and the reflux ratio of the top of the tower is 2:1, an overhead fraction and a bottoms fraction were obtained, and it was found by chromatography that the content of capronitrile in the overhead fraction was 98.5% by weight and cyclohexanone oxime in the bottoms fraction was 94.6% by weight.
Example 3
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) an overhead fraction was obtained in the same manner as in example 1.
2) Placing the overhead fraction into a 300ml hydrogenation kettle, adding 0.18g of 5% Pd/C catalyst (commercially available from Seisan Kaili chemical Co., Ltd., wherein the content of Pd accounts for 5 wt% of the catalyst), heating to about 150 ℃, introducing hydrogen for replacement for 5 times, maintaining the hydrogen pressure at 2MPa, stirring at the speed of 300r/min, and reacting for 1.5 hours to obtain a hydrogenation reaction product; the hydrogenation reaction product was analyzed by chromatography to obtain 72.8 wt% of capronitrile, 23.5 wt% of cyclohexanone, 0.7 wt% of 5-cyano-1-pentene residue, and 3.0 wt% of the remaining impurities;
3) the ammoximation reaction was carried out in accordance with the corresponding method as in example 1, except that the cyclohexanone ammoximation reaction was carried out under conditions such that the molar ratio of hydrogen peroxide to cyclohexanone in the product of the hydrogenation reaction was 1.0: 1, the molar ratio of ammonia to cyclohexanone in the hydrogenation reaction product is 1.5: 1, the weight ratio of the titanium silicalite molecular sieve to the reaction slurry is 0.04: 1; heating to about 70 ℃, stirring at a speed of 300r/min, reacting for 1 hour to obtain a reaction product, and distilling the reaction product to remove excessive ammonia and solvent tert-butyl alcohol to obtain a kettle bottom mixture (ammoximation reaction product); the bottom mixture was analyzed by chromatography to find that the content of hexanenitrile was 73.0 wt%, the content of cyclohexanone was 0.1 wt%, the content of cyclohexanone oxime was 23.2 wt%, and the content of the remaining impurities was 3.4 wt%.
4) Carrying out reduced pressure distillation on the kettle bottom mixture (ammoximation reaction product) by using a rectifying tower, wherein the pressure is 5kPa, the kettle temperature is lower than 130 ℃, the reflux ratio of the top of the tower is 2:1, so as to obtain a top fraction and a bottom material of the kettle, and the content of the capronitrile in the top fraction is 98.6 wt% as can be seen through chromatographic analysis; the content of cyclohexanone oxime in the kettle bottom material is 94.2 wt%.
Example 4
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) an overhead fraction was obtained in the same manner as in example 1.
2) Placing the overhead fraction into a 300ml hydrogenation kettle, adding 0.27g of 3% Pt/C catalyst (Yurui chemical Co., Ltd.), heating to about 120 ℃, introducing hydrogen for replacement for 5 times, keeping the hydrogen pressure at 5MPa, stirring at a speed of 300r/min, and reacting for 1 hour to obtain a hydrogenation reaction product; as a result of analyzing the hydrogenation reaction product by chromatography, the content of hexanenitrile was 72.5% by weight, the content of cyclohexanone was 23.2% by weight, the content of 5-cyano-1-pentene residue was 1.0% by weight, and the content of the remaining impurities was 3.3% by weight.
3) The ammoximation reaction was carried out in accordance with the corresponding method as in example 1, except that the cyclohexanone ammoximation reaction was carried out under conditions such that the molar ratio of hydrogen peroxide to cyclohexanone in the product of the hydrogenation reaction was 1.5: 1, the molar ratio of ammonia to cyclohexanone in the hydrogenation reaction product is 2:1, the weight ratio of the titanium silicalite molecular sieve to the reaction slurry is 0.02: 1; heating to about 80 ℃, stirring at the speed of 300r/min, and reacting for 1.5 hours. Obtaining a reaction product, and distilling the reaction product to remove excessive ammonia and solvent tert-butyl alcohol to obtain a kettle bottom mixture (ammoximation reaction product); the bottom mixture was analyzed by chromatography to find that the content of hexanenitrile was 72.8 wt%, the content of cyclohexanone was 0.2 wt%, the content of cyclohexanone oxime was 23.0 wt%, and the content of the remaining impurities was 4.0%.
4) And (3) distilling the kettle bottom mixture (ammoximation reaction product) by using a rectifying tower under reduced pressure, wherein the pressure is 3kPa, the kettle temperature is lower than 120 ℃, and the reflux ratio of the top of the tower is 2:1, obtaining an overhead fraction and a kettle bottom material, wherein the content of the hexanenitrile in the overhead fraction is 98.1 weight percent through chromatographic analysis. The total cyclohexanone oxime in the kettle bottom material is 94.0 wt%.
Example 5
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) an overhead fraction was obtained in the same manner as in example 1;
2) the hydrogenation reaction was carried out according to the corresponding method in example 1, except that the temperature in the hydrogenation reaction was 180 ℃ and the pressure was 6MPa, to obtain a hydrogenation reaction product; as a result of analyzing the hydrogenation reaction product by chromatography, the content of hexanenitrile was 71.5% by weight, the content of cyclohexanone was 22.5% by weight, the content of 5-cyano-1-pentene residue was 0.1% by weight, and the content of the remaining impurities was 5.9% by weight.
3) Carrying out an ammoximation reaction on the hydrogenation reaction product obtained in the step 2) according to the corresponding method in the example 1 to obtain a kettle bottom mixture (an ammoximation reaction product); as can be seen from the chromatographic analysis of the bottom mixture, the content of hexanenitrile was 71.7% by weight, the content of cyclohexanone was 0.1% by weight, the content of cyclohexanone oxime was 22.4% by weight, and the content of the remaining impurities was 5.8% by weight;
4) the still bottom mixture obtained in step 3) above was subjected to reduced pressure distillation in accordance with the corresponding method in example 1 to obtain an overhead fraction and a still bottom material. As can be seen from the chromatographic analysis, the content of hexanenitrile in the overhead fraction was 97.8% by weight, and the content of cyclohexanone oxime in the bottom product was 93.2% by weight.
Example 6
Illustrating the process for recovering hexanenitrile and cyclohexanone oxime from the light impurity components of the cyclohexanone oxime vapor phase Beckmann rearrangement product according to the present invention. The method comprises the following steps:
1) an overhead fraction was obtained in the same manner as in example 1.
2) Hydrogenation was carried out in the same manner as in example 1 to obtain a hydrogenation product.
3) The ammoximation reaction was carried out according to the corresponding method in example 1, with the difference that the cyclohexanone ammoximation reaction conditions were such that the molar ratio of hydrogen peroxide to cyclohexanone was 2.3: 1, the molar ratio of ammonia to cyclohexanone is 3.2: 1, heating to about 90 ℃, stirring at a speed of 300r/min, and reacting for 1.5 hours to obtain a kettle bottom mixture (an ammoximation reaction product); as can be seen from the chromatographic analysis of the bottom mixture, the content of hexanenitrile was 73.2 wt%, the content of cyclohexanone was 0.4 wt%, the content of cyclohexanone oxime was 23.1 wt%, and the content of the remaining impurities was 3.3 wt%;
4) the still bottom mixture obtained in step 3) was subjected to reduced pressure distillation in accordance with the corresponding method in example 1 to obtain an overhead fraction and a still bottom material, and it was confirmed by chromatography that the content of capronitrile in the overhead fraction was 98.3% by weight and the content of cyclohexanone oxime in the still bottom material was 93.8% by weight.
As is apparent from the above-mentioned contents of examples 1 to 6 according to the present invention, the major components of the overhead fraction obtained after distillation separation of the light impurity components from the cyclohexanone oxime vapor phase Beckmann rearrangement product are hexanenitrile, cyclohexanone, 5-cyano-1-pentene; the boiling points of the components are relatively low and close, and the three components are difficult to separate in a distillation mode except under the severe distillation condition; under the circumstances, the inventors of the present invention have creatively proposed that this part of the overhead fraction is subjected to hydrotreating to convert 5-cyano-1-pentene therein to hexanenitrile to simplify the components while increasing the content of high-value-added hexanenitrile and to adapt to the scheme of subsequent separation. For the hydrogenation reaction product, the main components are capronitrile and cyclohexanone, the boiling points of the two components are more similar, and the two components cannot be separated at all even under the conditions of 1.3kPa and 100 ℃; in this case, the inventors of the present invention have again creatively proposed that the portion of the hydrogenation reaction product is subjected to an ammoximation reaction so that cyclohexanone therein is converted into cyclohexanone oxime; at this time, the difference between the boiling points of the hexanenitrile and the cyclohexanone oxime is relatively large, and the separation can be carried out under simple distillation separation conditions.
The method provided by the invention can be used for obtaining high-purity hexanenitrile with high added value and cyclohexanone oxime which can be repeatedly used as a raw material for the cyclohexanone oxime gas-phase Beckmann rearrangement reaction, and can improve the economy of a gas-phase rearrangement process.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (25)
1. A process for recovering hexanenitrile and cyclohexanone oxime from a light impurity component of a cyclohexanone oxime vapor phase Beckmann rearrangement product, the process comprising:
1) distilling and separating the light impurity components to obtain tower top fraction;
2) carrying out hydrogenation reaction on the tower top fraction to obtain a hydrogenation reaction product;
3) performing cyclohexanone ammoximation reaction on the hydrogenation reaction product to obtain an ammoximation reaction product;
4) distilling and separating the ammoximation reaction product to obtain capronitrile and cyclohexanone oxime;
wherein the total content of hexanenitrile, cyclohexanone, 5-cyano-1-pentene in the overhead fraction is more than 90% of the total weight of the overhead fraction.
2. The process according to claim 1, wherein the total content of hexanenitrile, cyclohexanone, 5-cyano-1-pentene in the overhead fraction is more than 95% by weight based on the total weight of the overhead fraction.
3. The process of claim 1 or 2, wherein the step of distillative separation of the light impurity components is carried out under reduced pressure, the pressure being less than 100 kPa.
4. The method of claim 3, wherein the pressure is less than 50 kPa.
5. The method of claim 3, wherein the pressure is less than 20 kPa.
6. The method of claim 3, wherein the pressure is less than 10 kPa.
7. The process according to claim 3, wherein the pressure is 1-5kPa and the distillation temperature is 70-120 ℃.
8. The method of claim 1, wherein the hydrogenation reaction occurs in the presence of a hydrogenation catalyst, and the hydrogenation catalyst is one or more selected from nickel-based dehydrogenation catalysts, palladium-based dehydrogenation catalysts and platinum-based dehydrogenation catalysts.
9. The method of claim 8, wherein the nickel-based dehydrogenation catalyst is an amorphous nickel catalyst.
10. The process of claim 8, wherein the weight ratio of 5-cyano-1-pentene to hydrogenation catalyst in the overhead fraction is 50-500: 1.
11. The process as claimed in claim 10, wherein the weight ratio of 5-cyano-1-pentene to the hydrogenation catalyst in the overhead fraction is 100-300: 1.
12. The process according to any one of claims 1 and 8 to 11, wherein the hydrogenation reaction is carried out at a temperature of 80 to 200 ℃, a pressure of 0.5 to 6.0MPa and a time of 0.5 to 3 hours.
13. The method as claimed in claim 12, wherein the hydrogenation reaction is carried out at a temperature of 100 ℃ and 150 ℃, a pressure of 2.0 to 5.0MPa, and a time of 1 to 2 hours.
14. The process of claim 1, wherein the cyclohexanone ammoximation reaction occurs in the presence of an ammoximation catalyst, the ammoximation catalyst being a titanium silicalite catalyst.
15. The method of claim 14, wherein the ammoximation catalyst has an average particle size of 0.1-0.5 μm.
16. The method of claim 15, wherein the ammoximation catalyst is used in an amount of 1-10% by weight based on the total reaction slurry comprising the hydrogenation reaction product, ammonia, hydrogen peroxide, and a solvent.
17. The method of claim 16, wherein the ammoximation catalyst is used in an amount of 2-8% by weight based on the total weight of the reaction slurry.
18. The process of any one of claims 1 and 14-17, wherein the step of subjecting the hydrogenation reaction product to a cyclohexanone ammoximation reaction comprises: mixing and contacting the hydrogenation reaction product, an ammoximation catalyst, ammonia, hydrogen peroxide and a solvent, wherein the molar ratio of the hydrogen peroxide to the cyclohexanone in the hydrogenation reaction product is 0.5-2.0: 1, and the molar ratio of the ammonia to the cyclohexanone in the hydrogenation reaction product is 0.5-3: 1; the temperature of the cyclohexanone ammoximation reaction is 50-80 ℃, and the time is 0.5-3 h.
19. The process of claim 1, wherein the step of distillative separation of the cyclohexanone ammoximation reaction product is performed under reduced pressure, said pressure being less than 100 kPa.
20. The method of claim 19, wherein the pressure is less than 50 kPa.
21. The method of claim 19, wherein the pressure is less than 20 kPa.
22. The process of claim 19, wherein the pressure is 1-10kPa and the distillation temperature is 80-130 ℃.
23. The process of claim 1, wherein the light impurities component consists of capronitrile, cyclohexanone, 5-cyano-1-pentene, aniline and its homologues, N-methyl caprolactam and impurities, and the total content of the capronitrile, cyclohexanone, 5-cyano-1-pentene, aniline and its homologues, and N-methyl caprolactam is greater than 90% by weight of the total light impurities component.
24. The method of claim 23, wherein the light impurity component comprises, based on total weight of the light impurity component: 3-10% by weight of hexanenitrile, 5-15% by weight of cyclohexanone, 10-35% by weight of 5-cyano-1-pentene, 10-15% by weight of aniline and its homologues, 10-30% of N-methylcaprolactam and 5-10% by weight of impurities.
25. The process according to claim 1, wherein the cyclohexanone oxime separated by distillation is recycled as a starting material for the cyclohexanone oxime vapor phase Beckmann rearrangement reaction.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101274902A (en) * | 2007-03-29 | 2008-10-01 | 住友化学株式会社 | Method for recovering cyclohexanone oxime |
| CN101429148A (en) * | 2007-11-08 | 2009-05-13 | 中国石油化工股份有限公司 | Process for production of Epsilon-hexanolactam |
| CN106146374A (en) * | 2015-04-02 | 2016-11-23 | 中国石油化工股份有限公司 | A kind of method recycling cyclohexanone-oxime vapour phase rearrangement product fractionation weight residual liquid |
-
2017
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101274902A (en) * | 2007-03-29 | 2008-10-01 | 住友化学株式会社 | Method for recovering cyclohexanone oxime |
| CN101429148A (en) * | 2007-11-08 | 2009-05-13 | 中国石油化工股份有限公司 | Process for production of Epsilon-hexanolactam |
| CN106146374A (en) * | 2015-04-02 | 2016-11-23 | 中国石油化工股份有限公司 | A kind of method recycling cyclohexanone-oxime vapour phase rearrangement product fractionation weight residual liquid |
Non-Patent Citations (2)
| Title |
|---|
| 浅谈己内酰胺产品中的杂质;罗晓强等;《化工时刊》;20120731;第26卷(第7期);第38-41页 * |
| 环己酮肟气相贝克曼重排反应产物己内酰胺的精制研究;谢丽等;《石油炼制与化工》;20150531;第46卷(第5期);第7-11页 * |
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