CN103420913A - Crystallization refining method and preparation method of caprolactam - Google Patents

Abstract

A crystallization refining method of caprolactam is characterized by comprising a contact processing step of an epsilon-caprolactam crude product containing solution and seed crystal, the contact processing is performed in a metastable region of the epsilon-caprolactam crude product containing solution, and the seed crystal is a caprolactam particle of 2-80 mesh. Large-particle complete-crystalline-form crystals are obtained by the method, more than 90% of particles are in a particle region of 0.5-3 mm, and the crystals are conducive to industrial separation.

Description

A kind of crystal refining method of hexanolactam and preparation method

Technical field

The present invention relates to the crystal refining method of the thick product of a kind of ε-caprolactam and the preparation method of hexanolactam.

Background technology

ε-caprolactam is one of important raw material of synthon and synthetic resins, mainly for the manufacture of tynex (nylon 6), resin and film etc.At present, the method for industrial production hexanolactam is to adopt oleum to make catalysts and solvents, cyclohexanone-oxime generation liquid phase Beckmann rearrangement.This technique exists the deficiencies such as etching apparatus, contaminate environment and economic benefit be undesirable the relatively large ammonium sulfate of by-product.

Cyclohexanone-Oxime Gas Phase Beckmann Rearrangement on solid acid catalyst is to realize the novel process of ε-caprolactam without the sulphur ammonium, have without problems such as equipment corrosion, non-environmental-pollutions, the separating-purifying of product also will be simplified greatly, therefore without the vapor phase beckmann rearrangement reaction novel process of sulphur ammonium, receive insider's very big concern.

For development is applicable to the solid acid catalyst of vapor phase beckmann rearrangement reaction, the investigator carried out a large amount of research to main catalyzer of two classes such as oxide compound (composite oxides), zeolite molecular sieves both at home and abroad, all can prepare ε-caprolactam.

Yet the ε-caprolactam that these methods obtain contains plurality of impurities.As everyone knows, ε-caprolactam is the raw material that is used to prepare polymeric amide, requirement has very high specification of quality for the preparation of polymeric amide the further ε-caprolactam product of manufacturing synthon and synthetic resins, the impurity of μ g/g level all can affect the polyreaction of follow-up ε-caprolactam, is difficult for forming long filament.Therefore, adopt the method for various separating-purifyings to obtain crude epsi-caprolactam, then adopt various refining methods finally to make highly purified ε-caprolactam, highly purified like this ε-caprolactam could be for the manufacture of products such as synthon, synthetic resins and films.

The separating-purifying of liquid phase Beckmann rearrangement ε-caprolactam need to pass through following operation: reset neutralization, the extraction of sulphur ammonium and stripping, benzene extraction, water extraction, ion-exchange, hydrogenation, triple effect evaporation, distillation etc., the separating-purifying operation of reaction product is more, and the existence of partly cause inorganic salt ammonium sulfate causes.

Can not fully remove the impurity with the ε-caprolactam chemical properties similar with the separating and purifying method of extraction, distillation, ion-exchange, or the by product that is close of boiling point and ε-caprolactam.At this moment, taking the method for hydrogenation is a kind of effectively means.On the one hand, by hydrogenation reaction, can make tetrahydroazepine-2-ketone and structure isomeride thereof be converted into ε-caprolactam; On the other hand, can effectively improve the potassium permanganate absorption value in product by hydrogenation reaction.

In sum, common separating and purifying method, as single means or multiple means combinations such as distillation, rectifying, extraction, ion-exchange, absorption and hydrogenation, might not obtain the ε-caprolactam of industrial required purity.

Preparing highly purified chemical substance with crystallization method is the most ancient and one of effective separation method, and polymer level CPL is heat-sensitive substance, requires again foreign matter content low, utilizes the crystallization process separating-purifying to cause the extensive concern of each large caprolactam production company.Bayer　Bitterfeld　GmbH, Switzerland INVENT, Dutch DSM, SUMITOMO CHEMICAL etc. were all developed the caprolactam refining technique relevant to crystallization in succession, crystallization method comprises water, organic solvent crystallization and solventless crystalline, the solventless crystalline product particle is little, fouling is serious, cause the industrial continuous operation that is difficult to, hindered its development.

The separating-purifying process for purification of CN 101070298A and the disclosed ε-caprolactam of CN 101070299A, the method is included in the step containing crystallization ε-caprolactam in the ethereal solution of crude epsi-caprolactam or halohydrocarbon solution.Described separating-purifying process for purification is that the alcoholic solution of the ε-caprolactam that will obtain through vapor phase beckmann rearrangement reaction is distilled, and removes alcohol, lower-boiling impurity and high-boiling-point impurity, obtains crude epsi-caprolactam; The molten state crude epsi-caprolactam is dissolved in ether or halohydrocarbon, carry out crystallisation by cooling and carry out centrifugation and separate and obtain the ε-caprolactam crystal through solvent wash, and under hydrogenation catalyst exists, make ε-caprolactam contact and carry out hydrogenation reaction with hydrogen, thereby the extinction value, volatility base number and the potassium permanganate absorption value that obtain ε-caprolactam meet the ε-caprolactam product that Industrial products require.

CN1332158A has reported the separating and purifying method of the crude caprolactam obtained by vapor phase beckmann rearrangement reaction, and the method comprises: the important procedures such as distillation, recrystallization and hydrofining.

The ubiquitous problem of aforesaid method is the hexanolactam particle obtained little (being less than 600 μ m), and the solid-liquid separation difficulty particularly can exist solid-liquid conveying, solid-difficulties such as liquid separation in the engineering amplification process, affects the continuous production problem of hexanolactam.

Summary of the invention

One of purpose of the present invention is on the basis of existing technology, provide a kind of simple and effective, can access even macrobead, be conducive to the new crystallization method of the thick product of ε-caprolactam of industrial applicability.

Two of purpose of the present invention is that a kind of preparation method who meets the hexanolactam that Industrial products require is provided on new crystallization method basis.

The present inventor is surprised to find that on the basis of great many of experiments, in the operation steps of the crystallization at crystallisation process, while throwing in the solution of the thick product of hexanolactam in a small amount of hexanolactam particle Zai Jiewen district, certain Tc can obtain larger particle degree and the complete hexanolactam crystal of crystalline form in interval, is beneficial to industrial separation.Based on this, complete the present invention.

Therefore, the crystal refining method of hexanolactam provided by the invention, it is characterized in that the method comprises the step that the solution containing the thick product of ε-caprolactam is contacted to processing with crystal seed, said contact is processed and is being carried out containing in the solution De Jiewen district of the thick product of ε-caprolactam, and said crystal seed is 2～80 purpose hexanolactam particles.

The present invention also provides a kind of preparation method of hexanolactam, comprise that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of the thick product of ε-caprolactam through distillation, the step of crystallization, solvent wash after crystallization, separate the step that obtains the ε-caprolactam crystal, at hydrogenation catalyst, exist, the step that ε-caprolactam is contacted with hydrogen, and the step that finally obtains the ε-caprolactam finished product, it is characterized in that in the step of said crystallization, comprise the process that crystal seed is contacted with the solution of the thick product of ε-caprolactam in the Jie Wen district, said crystal seed is 2～80 purpose hexanolactam particles.。

The crystallization method of the thick product of ε-caprolactam provided by the invention, can obtain the complete and oarse-grained crystal of crystalline form, and in its crystal obtained, 90% above particle, between 0.5～3mm pars granulosa, is particularly conducive to industrial separation.The preparation method of hexanolactam provided by the invention, can obtain purity at the hexanolactam finished product more than 99.995%, meets the Industrial products requirement.

The accompanying drawing explanation

Fig. 1 is saturation solubility curve and the supersaturation solubility curve schematic diagram of hexanolactam in solvent.

Fig. 2 is particle size distribution figure, wherein, and the size distribution curve of the ε-caprolactam crystal grain that curve 1 obtains for Comparative Examples 1, the size distribution curve of the ε-caprolactam crystal grain that curve 2 obtains for embodiment 1.

Fig. 3 is particle size distribution figure, wherein, and the size distribution curve of the ε-caprolactam crystal grain that curve 1 obtains for Comparative Examples 3, the size distribution curve of the ε-caprolactam crystal grain that curve 2 obtains for embodiment 8.

Fig. 4 is particle size distribution figure, wherein, and the size distribution curve of the ε-caprolactam crystal grain that curve 1 obtains for Comparative Examples 5, the size distribution curve of the ε-caprolactam crystal grain that curve 2 obtains for embodiment 15.

Embodiment

Regional Wei Jiewen district between saturation solubility curve and supersaturation solubility curve, Fig. 1 has shown saturation solubility curve and the supersaturation solubility curve of hexanolactam in solvent of experimental determination.The present inventor finds, if do not add crystal seed in the Zai Jiewen district or be not subject to other conditioned stimulus, and crystallize out automatically not, if add crystal seed, solute can be separated out and grow up on crystal seed.For industrial operation, there is important meaning in the ，Jie Wen district.The contriver further finds, crystallisation process is controlled to the Jie Wen district and, in lower supersaturation solubleness, can only has in a long time a small amount of nucleus to produce, and be mainly to add growing up of crystal seed, so can obtain granularity crystalline product greatly and uniformly; If, and crystallisation process is in sphere of instability, in higher supersaturation solubleness, can breaks out nucleation, the crystalline product particle obtained is very little, is unfavorable for very much the solid-liquid separation of hexanolactam, to engineering, amplifies and causes very large difficulty.Therefore, if in crystallisation process, add a small amount of crystal seed in the Zai Jiewen district, control Precipitation Temperature well, make hexanolactam in low degree of supersaturation scope, the growth that can be conducive to crystal with grow up, thereby obtain macrobead, crystalline product uniformly.

The crystal refining method of hexanolactam provided by the invention, it is characterized in that the method comprises the step that the solution containing the thick product of ε-caprolactam is contacted with crystal seed, said contact is being carried out containing in the solution De Jiewen district of the thick product of ε-caprolactam, and said crystal seed is 2～80 purpose hexanolactam particles.

Wherein, said containing in the solution of the thick product of ε-caprolactam, the part by weight of the thick product of ε-caprolactam and organic solvent is 1:1～10, and said crystal seed accounts for 1～15 heavy % of the thick product of ε-caprolactam, and said contact is carried out in 45～62 ℃ of temperature in said Jie Wen district.Said organic solvent can but be not limited to be selected from one or more the mixture in the organic solvents commonly used such as straight chain aliphatic hydrocarbon, a chain aliphatic hydrocarbon, cycloaliphatic hydrocarbon, straight-chain halogenated hydrocarbon, side chain halohydrocarbon, dihalo hydrocarbon, three halohydrocarbon, linear, branched chain ether, diether, alcohol ether and alkene ether; Further, said organic solvent is selected from one or more in normal hexane, normal heptane, octane, positive nonane, n-decane, methyl hexane, octane-iso, hexanaphthene, methylcyclopentane, methylcyclohexane, positive chloropropane, different chloropropane, n-propylcarbinyl chloride, secondary chlorobutane, different chlorobutane, three grades of chlorobutanes, n-Propyl Bromide, different N-PROPYLE BROMIDE, 1-n-butyl bromide, 2-n-butyl bromide, ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

The present invention goes for the crystal refining process of the thick product of hexanolactam that different process obtains.Preferably, the thick product of said ε-caprolactam is that the zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtain after distilling out reaction solvent.In the thick product of described ε-caprolactam, usually contain the hexanolactam that purity is 99.0～99.6%, and a small amount of tetrahydroazepine-2-ketone, hexanal, pimelinketone,, other weight impurity such as cyclonene, 2-heptanone, cyclohexanone-oxime, n-valeramide, n-caproamide, adipimide, dimethyl-aniline, N-methyl-hexanolactam, octahydro acridine, octahydro azophenlyene, tetrahydro naphthylamine, tetrahydro carbazole.

In the inventive method, the step of the solution of the thick product of ε-caprolactam in said crystal seed Yu Jiewen district contact can be carried out once, also can carry out repeatedly.

In a specific embodiment of the present invention, to using the organic solvent of ether as the thick product of hexanolactam,, comprise crystal seed is added to the step in the ethereal solution of the thick product of ε-caprolactam in the Jie Wen district, wherein said ether is selected from one or more in linear, branched chain ether, diether, alcohol ether and alkene ether, and said crystal seed is 2～80 purpose hexanolactam particles.

In more detail, the crystallization method of ε-caprolactam provided by the invention, is characterized in that the method comprises the thick product of ε-caprolactam is dissolved in said ether, obtains the ethereal solution of the thick product of ε-caprolactam; Carry out thermostatical crystallization with the ethereal solution contact of the thick product of ε-caprolactam of 45～62 ℃ of temperature in said crystal seed Yu Jiewen district again, obtain the hexanolactam crystal grain, then, through solid-liquid separation, reclaim the hexanolactam crystal.

In method provided by the invention, preferably with the ethereal solution contact of the thick product of ε-caprolactam of 50～60 ℃ of temperature ranges in said crystal seed Yu Jiewen district, carry out thermostatical crystallization, substantially keep this temperature range to make the hexanolactam of large crystal grain form gradually; Then cool the temperature to crystallization final temperature (generally at 35～45 ℃), carry out solid-liquid separation, obtain the hexanolactam crystal of 90% above particle between 0.5～3mm pars granulosa in crystal.

In the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1: 1～10; Further preferred, in the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1: 1.2～8; Further preferred, in the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1: 2～5.

The thick product of said ε-caprolactam preferably but to be not limited to be that zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtains after distilling out reaction solvent.In the thick product of described ε-caprolactam, usually contain the hexanolactam that purity is 99.0～99.6%, and a small amount of tetrahydroazepine-2-ketone, hexanal, pimelinketone,, other weight impurity such as cyclonene, 2-heptanone, cyclohexanone-oxime, n-valeramide, n-caproamide, adipimide, dimethyl-aniline, N-methyl-hexanolactam, octahydro acridine, octahydro azophenlyene, tetrahydro naphthylamine, tetrahydro carbazole.

In method provided by the invention, said crystal seed is the hexanolactam particle, and its order number is 2～80 orders.Said order number in the present invention, its concept refers in the length of 1 inch (25.4mm), arrange in total how many holes, is exactly how many orders.For example, 10 orders are illustrated in the length of 1 inch, are arranged with altogether 10 holes; And 40 orders are illustrated in the length of 1 inch, be arranged with altogether 40 holes, 80 orders are illustrated in the length of 1 inch, are arranged with altogether 80 holes.The implication of said 2～80 purpose hexanolactam particles refers to and can leak and the hexanolactam particle that can not leak from 80 purpose mesh from 2 purpose mesh.

In method provided by the invention, said crystal seed is 2～80 purpose hexanolactam particles, preferably accounts for 1～15 heavy % of the thick product of ε-caprolactam.The order numerical example of said crystal seed, as be 10～20 orders, can be also 20～40 orders, can also be 30～60 orders, or can be 40～80 orders.According to the difference of the order number of crystal seed size interval range, the part by weight of crystal seed and the thick product of ε-caprolactam is also differentiated.For example, at 40～60 purpose crystal seeds, can account for 1～5 heavy % of the thick product of ε-caprolactam, preferably 2～4 weigh %; 20～40 purpose crystal seeds, can account for 5～10 heavy % of the thick product of ε-caprolactam, preferably 6～9 weigh %; 6～20 purpose crystal seeds, can account for 10～15 heavy % of the thick product of ε-caprolactam, preferably 11～14 weigh %.

In method provided by the invention, said ether is selected from one or more the mixture in linear, branched chain ether, diether, alcohol ether or alkene ether.Said ether has the boiling range of 30～150 ℃; Further preferably, said ethereal solution has the boiling range of 50～100 ℃; Further preferred, said ethereal solution has the boiling range of 60～90 ℃.Under the prerequisite of the boiling range that meets above-mentioned said ether, further, the concrete example of said ether can be selected from but be not limited to one or more in ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

In the inventive method, the treatment step contacted in the ethereal solution of said crystal seed and the thick product of ε-caprolactam in the Jie Wen district can carry out once, also can carry out repeatedly.

The present invention is on the basis of the crystallization method of the above-mentioned thick product of ε-caprolactam, a kind of preparation method of hexanolactam also is provided, comprise that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of the thick product of ε-caprolactam through distillation, the step of crystallization, solvent wash after crystallization, separate the step that obtains the ε-caprolactam crystal, at hydrogenation catalyst, exist, the step that ε-caprolactam is contacted with hydrogen, and the step that finally obtains the ε-caprolactam finished product, it is characterized in that in the step of said crystallization, comprise the process that crystal seed is contacted with the solution of the thick product of ε-caprolactam in the Jie Wen district, said crystal seed is 2～80 purpose hexanolactam particles.Wherein, said containing in the solution of the thick product of ε-caprolactam, the part by weight of the thick product of ε-caprolactam and organic solvent is preferably 1: 1～and 10, said crystal seed preferably accounts for 1～15 heavy % of the thick product of ε-caprolactam, and said contact is preferably carried out in 45～62 ℃ of temperature in said Jie Wen district.Said organic solvent can but be not limited to be selected from one or more the mixture in the organic solvents commonly used such as straight chain aliphatic hydrocarbon, a chain aliphatic hydrocarbon, cycloaliphatic hydrocarbon, straight-chain halogenated hydrocarbon, side chain halohydrocarbon, dihalo hydrocarbon, three halohydrocarbon, linear, branched chain ether, diether, alcohol ether and alkene ether; Further, said organic solvent is selected from one or more in normal hexane, normal heptane, octane, positive nonane, n-decane, methyl hexane, octane-iso, hexanaphthene, methylcyclopentane, methylcyclohexane, positive chloropropane, different chloropropane, n-propylcarbinyl chloride, secondary chlorobutane, different chlorobutane, three grades of chlorobutanes, n-Propyl Bromide, different N-PROPYLE BROMIDE, 1-n-butyl bromide, 2-n-butyl bromide, ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

In a specific embodiment of the present invention, using ether as solvent.This scheme comprises that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of the thick product of ε-caprolactam through distillation, the step of crystallization, solvent wash after crystallization, separate the step that obtains the ε-caprolactam crystal, at hydrogenation catalyst, exist, the step that ε-caprolactam is contacted with hydrogen, and the step that finally obtains the ε-caprolactam finished product, it is characterized in that in the step of said crystallization, comprise the process that crystal seed is contacted with the ethereal solution of the thick product of ε-caprolactam in the Jie Wen district, wherein said ether is selected from the straight chain aliphatic hydrocarbon, one or more in chain aliphatic hydrocarbon and cycloaliphatic hydrocarbon, said crystal seed is 2～80 purpose hexanolactam particles.

In the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1:1～10; Preferably, the part by weight of the thick product of said ε-caprolactam and ether is 1: 1.2～8; Preferred, the part by weight of the thick product of said ε-caprolactam and ether is 1: 2～5.

The thick product of said ε-caprolactam preferably but to be not limited to be that zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtains after distilling out reaction solvent.The thick product of said ε-caprolactam refers to the hexanolactam obtained through simple distillation.In the thick product of said ε-caprolactam, usually contain the hexanolactam that purity is 99.0～99.6%, and tetrahydroazepine-2-ketone, hexanal, pimelinketone,, other weight impurity such as cyclonene, 2-heptanone, cyclohexanone-oxime, n-valeramide, n-caproamide, adipimide, dimethyl-aniline, N-methyl-hexanolactam, octahydro acridine, octahydro azophenlyene, tetrahydro naphthylamine, tetrahydro carbazole.

Wherein, said crystal seed is 2～80 purpose hexanolactam particles; Preferably, said crystal seed is 20～60 purpose hexanolactam particles; Preferred, said crystal seed is 20～40 purpose hexanolactam particles.

In method provided by the invention, said crystal seed is 10～80 purpose hexanolactam particles, 1～15 heavy % that its add-on is the thick product of ε-caprolactam.The order numerical example of said crystal seed, as be 10～20 orders, can be also 20～40 orders, can also be 30～60 orders, or can be 40～80 orders.Count the difference of scope according to the order of crystal seed, the part by weight of crystal seed and the thick product of ε-caprolactam is also differentiated.For example, at 40～60 purpose crystal seeds, can account for 1～5 heavy % of the thick product of ε-caprolactam, preferably 2～4 weigh %; 20～40 purpose crystal seeds can account for 5～10 heavy % of the thick product of ε-caprolactam, preferably 6～9 weigh %; The crystal seed that 20 orders are following, can account for 10～15 heavy % of the thick product of ε-caprolactam, preferably 11～14 weigh %.

In method provided by the invention, said ether is selected from one or more in linear, branched chain ether, diether, alcohol ether or alkene ether.Said ether has the boiling range of 30～150 ℃; Further preferably, said ethereal solution has the boiling range of 50～100 ℃; Further preferred, said ethereal solution has the boiling range of 60～90 ℃.Meeting under the prerequisite of above-mentioned boiling range, further, the concrete example of said ether can be selected from but be not limited to one or more in ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

In the step of said crystallization, crystal seed is contacted to the process of processing with the ethereal solution of the thick product of ε-caprolactam in the Jie Wen district and carry out repeatedly.

In the step of said crystallization, crystallization mode can be considered the modes such as crystallisation by cooling, evaporative crystallization, vacuum insulation crystallization; Crystallizer can adopt general crystallizer, as FC type crystallizer, Oslo type crystallizer, DTB type crystallizer, DP type crystallizer, Messo type crystallizer etc.

In the preparation method of hexanolactam provided by the invention, also include and comprise that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of crude epsi-caprolactam through distillation.Wherein, said reaction solvent is alcohol, and said alcohol is preferably methyl alcohol and/or ethanol.Said distillation, by reaction solvent recycling use after distillation, obtain the water-epsilon-caprolactam mixture that contains water, light impurity component, heavy seeds component simultaneously, progressively distillation is dewatered again, remove light constituent and heavy seeds component, the thick product of ε-caprolactam that acquisition purity is 99.0～99.6%.

In the preparation method of hexanolactam provided by the invention, also include solvent wash after crystallization and separate the step that obtains the ε-caprolactam crystal, said solvent wash is generally selected the compound identical with recrystallisation solvent, such as haloalkane, ether or other hydro carbons.The consumption of solvent wash and hexanolactam crystal is generally 0.8～1.5:1, at room temperature stirs certain hour, can adopt afterwards whizzer to carry out the solid-liquid separation, obtains the hexanolactam crystal, as hydrogenating materials.

In the preparation method of hexanolactam provided by the invention, also include under hydrogenation catalyst exists the step of the hydrogenation that ε-caprolactam is contacted with hydrogen.We know, with the separating and purifying method of extraction, distillation, ion-exchange, can not fully remove the impurity with the ε-caprolactam chemical properties similar, or the by product that is close of boiling point and ε-caprolactam.At this moment, taking the method for hydrogenation is a kind of effectively means.On the one hand, by hydrogenation reaction, can make tetrahydroazepine-2-ketone and structure isomeride thereof be converted into ε-caprolactam; On the other hand, can effectively improve the potassium permanganate absorption value in product by hydrogenation reaction.Hexanolactam hydrofining can adopt aqueous solution hydrogenation, also can adopt the molten state hexanolactam to carry out hydrogenation; The reactor types of hexanolactam hydrofining is not particularly limited, as adopt magnetically stabilized bed reactor device, fixed-bed reactor or slurry bed reactor all can, fixed-bed reactor can select molten state hexanolactam or caprolactam water solution to carry out hydrofining; Catalyzer can be nickel catalyst, can be also the precious metal palladium series catalysts.Hydroconversion condition generally carries out under 80～150 ℃, 2～15atm pressure.

In the preparation method of hexanolactam provided by the invention, also include the step that obtains the ε-caprolactam finished product, if the product that hexanolactam hydrofining obtains contains relatively large water, need to carry out triple effect evaporation and (decompression) distillation, finally obtain qualified caprolactam product; If hexanolactam hydrofining is to adopt the molten state hexanolactam, directly carries out (decompression) distillation and can obtain qualified caprolactam product.

Below by embodiment, the invention will be further described, but therefore do not limit content of the present invention.

In embodiment, by the purity of 6890 type gas chromatographs (Agilent company) analyzing crystal; Characterize crystal boundary with 40 times of enlargement ratios of opticmicroscope (SG2-6XB-PC type).

The desk-top centrifugal filter of TD5LG type, Saite Hunan, Hunan Instrument Ltd..

S7401-II type stepless time adjustment electric mixer, Juancheng, Shandong Yongxing instrument plant.

Mastersizer-2000 type particles distribution instrument.

Embodiment 1

Cyclohexanone-Oxime Gas Phase Beckmann Rearrangement is carried out in the 80ml fixed-bed reactor, the internal diameter of reactor is 28mm, the molecular sieve catalyst loadings of high silica alumina ratio MFI structure is 9.45g(Φ 1.8mm bar shaped catalyst), reaction pressure 0.1MPa, 365 ℃-385 ℃ of catalyst bed reaction temperature, carrier gas flux is 3.0L/gcat/hr, and cyclohexanone-oxime WHSV is 2h ^-1, the dividing potential drop scope of mixture: cyclohexanone-oxime 5.5kPa-11.6kPa, methyl alcohol (solvent) 36.9kPa-70.6kPa, nitrogen (carrier gas) 19.4kPa-52.6kPa.Reaction product is collected by-5 ° of C ethylene glycol solution circulating coolings, obtains the reaction product containing ε-caprolactam.

At first adopt the method for simple distillation to be distilled this reaction mixture, remove methyl alcohol, lower-boiling impurity and high-boiling-point impurity, finally obtain crude epsi-caprolactam.On Agilent company 6890 type gas chromatographs, (hydrogen flame ionization sensor, PEG20M capillary chromatographic column, column length 50m) analyzed crude epsi-caprolactam, and its chief component is: 99.2% ε-caprolactam.

Get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, then add 130g isopropyl ether recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 54 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.5g16～40 mesh sieve mesh numbers in there-necked flask, at 50～57 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 45 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve is shown in the curve 2 of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 104.5g99.96% hexanolactam crystal and centrifuge mother liquor isopropyl ether, and yield reaches 79%.Centrifuge mother liquor isopropyl ether solvent can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add 100g isopropyl ether cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.985% ε-caprolactam crystal and isopropyl ether solvent, yield reaches 95% left and right.The isopropyl ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 160s, E value<0.5.

Hydrogenation reaction: get the 99.985% hexanolactam crystal of 100g after the isopropyl ether solvent wash, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42600s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Comparative Examples 1

This Comparative Examples illustrates under same crystallization condition, impact crystal size distributed without crystal seed.

Condition is with embodiment 1, and difference is not add crystal seed.Resulting caprolactam product quality, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.Although this quality product is no problem, the hexanolactam particle of crystallization gained is thin, there is no intensity, industrial, is difficult to carry out the solid-liquid separation.

The crystal size distribution curve of products obtained therefrom is shown in the curve 1 of Fig. 2.

Find out from the crystal size distribution curve of Fig. 2, adding with not add the crystal size distributional difference obtained under the crystal seed condition obvious.In Comparative Examples 1, do not add the most probable of crystal size after seeded crystallization and be distributed in 550 μ m places, and embodiment 1 most probable of crystal size after adding seeded crystallization is distributed in 950 μ m places, crystal grain obviously increases, most probable distributes has increased by 400 μ m, and wherein large crystal grain reaches 2500 μ m left and right.Illustrate that the Zai Jiewen district adds crystal seed crystallisation process can be controlled to low degree of supersaturation zone, be conducive to control the number of nucleus, more be conducive to the growth of crystal.

Comparative Examples 2

Condition, with embodiment 2, adds 3.0g80～120 purpose crystal seeds, because seed particles is too thin, dissolved very soon, and does not add coming to the same thing of crystal seed.

Embodiment 2

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g methyl tertiary butyl ether recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 56 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 35 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 114g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 86%.The centrifuge mother liquor methyl tert-butyl ether solvent can be carried out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add 120g methyl tertiary butyl ether cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.98% ε-caprolactam crystal and washing mother liquor, yield reaches 92% left and right.The methyl tertiary butyl ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 120s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 100g after the methyl tert-butyl ether solvent washing, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 40000s, E value<0.04, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 3

As described in Example 1, get the crude epsi-caprolactam that 65g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g isopropyl ether recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 54 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 35 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 60.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 89%.Centrifuge mother liquor isopropyl ether solvent can carry out recycling.60g hexanolactam crystal is turned back in the 500ml there-necked flask, add 60g isopropyl ether cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.97% ε-caprolactam crystal and washing mother liquor, and yield reaches 95% left and right.The isopropyl ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 150s, E value<0.6.

Hydrogenation reaction: get the 99.97% hexanolactam crystal of 40g after the isopropyl ether solvent wash, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7a tm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 4

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g ether recrystallisation solvent solution, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 55 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 10g6～10 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 37 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 116.8g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 84%.The centrifuge mother liquor ether solvent can carry out recycling.110g hexanolactam crystal is turned back in the 500ml there-necked flask, add the 110g ether solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.96% ε-caprolactam crystal and washing mother liquor, and yield reaches 90% left and right.The ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 120s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 100g after the ether solvent washing, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 36000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 5

As described in Example 1, get the crude epsi-caprolactam that 90g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g isopropyl ether recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53 ℃ of left and right from 70 ℃, adds 5.2g40～60 purpose hexanolactam crystal in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 80g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 84% left and right.Centrifuge mother liquor isopropyl ether solvent can carry out recycling.70g hexanolactam crystal is turned back in the 500ml there-necked flask, add 90g isopropyl ether cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.98% ε-caprolactam crystal and washing mother liquor, and yield reaches 92% left and right.The isopropyl ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 180s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 40g after the isopropyl ether solvent wash, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 6

As described in Example 1, get the crude epsi-caprolactam that 70g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 260g isopropyl ether recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 8.0g6～10 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 64g99.96% hexanolactam crystal and centrifuge mother liquor, and yield reaches 83% left and right.Centrifuge mother liquor isopropyl ether solvent can carry out recycling.60g hexanolactam crystal is turned back in the 500ml there-necked flask, add 60g isopropyl ether cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.99% ε-caprolactam crystal and washing mother liquor, and yield reaches 93% left and right.The isopropyl ether cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 240s, E value<0.6.

Hydrogenation reaction: get the 99.99% hexanolactam crystal of 40g after the isopropyl ether solvent wash, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7a tm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 7

As described in Example 1, get the crude epsi-caprolactam that 90g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the isopropyl ether: normal heptane=1:3) recrystallisation solvent that adds again 130g isopropyl ether and normal heptane, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 52.5 ℃ of left and right from 70 ℃, adds 3.0g20～40 purpose hexanolactam crystal in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 45 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 features of Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 76g99.97% hexanolactam crystal and centrifuge mother liquor, and yield reaches 82% left and right.The mixture of centrifuge mother liquor isopropyl ether and normal heptane can carry out recycling.70g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the isopropyl ether: normal heptane=1:3) that adds 70g isopropyl ether and normal heptane, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain 99.98% ε-caprolactam crystal and washing mother liquor, yield reaches 94.5% left and right.The mixture of isopropyl ether and normal heptane is reclaimed.The PM value of the ε-caprolactam obtained is 180s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 40g after the mixture washing of isopropyl ether and normal heptane, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 8

Cyclohexanone-Oxime Gas Phase Beckmann Rearrangement is carried out in the 80ml fixed-bed reactor, the internal diameter of reactor is 28mm, the molecular sieve catalyst loadings of high silica alumina ratio MFI structure is 9.45g(Φ 1.8mm bar shaped catalyst), reaction pressure 0.1MPa, 365 ℃-385 ℃ of catalyst bed reaction temperature, carrier gas flux is 3.0L/gcat/hr, and cyclohexanone-oxime WHSV is 2h ^-1, the dividing potential drop scope of mixture: cyclohexanone-oxime 5.5kPa-11.6kPa, methyl alcohol (solvent) 36.9kPa-70.6kPa, nitrogen (carrier gas) 19.4kPa-52.6kPa.Reaction product is collected by-5 ° of C ethylene glycol solution circulating coolings, obtains the reaction product containing ε-caprolactam.

At first adopt the method for simple distillation to be distilled this reaction mixture, remove methyl alcohol, lower-boiling impurity and high-boiling-point impurity, finally obtain crude epsi-caprolactam.On Agilent company 6890 type gas chromatographs, (hydrogen flame ionization sensor, PEG20M capillary chromatographic column, column length 50m) analyzed crude epsi-caprolactam, and its chief component is: 99.2% ε-caprolactam.

Get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds again 130g hexanaphthene and normal heptane, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 57 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.5g16～40 mesh sieve mesh numbers in there-necked flask, at 50～57 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 43 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 105.4g99.96% hexanolactam crystal and centrifuge mother liquor ether, and yield reaches 81%.The centrifuge mother liquor solvent can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds 100g hexanaphthene and normal heptane, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain the mixture of 99.985% ε-caprolactam crystal and hexanaphthene and normal heptane, yield reaches 94% left and right.The admixture solvent of hexanaphthene and normal heptane is reclaimed.The PM value of the ε-caprolactam obtained is 160s, E value<0.5.

Hydrogenation reaction: get the 99.985% hexanolactam crystal of 100g after the mixture once washing of hexanaphthene and normal heptane, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Comparative Examples 3

This Comparative Examples illustrates under same crystallization condition, impact crystal size distributed without crystal seed.

Condition is with embodiment 8, and difference is not add crystal seed.Resulting caprolactam product quality, the PM value is 46000s, E value<0.03.This quality product is no problem, but particle is thin, there is no intensity, industrial, is difficult to carry out the solid-liquid separation.

The crystal size distribution curve of products obtained therefrom is shown in the curve 1 of Fig. 2.

Find out from the crystal size distribution curve of Fig. 3, adding with not add the crystal size distributional difference obtained under the crystal seed condition obvious.In Comparative Examples 3, do not add the most probable of crystal size after seeded crystallization and be distributed in 600 μ m places, and embodiment 8 most probable of crystal size after adding seeded crystallization is distributed in 900 μ m places, crystal grain obviously increases, most probable distributes has increased by 300 μ m, and wherein large crystal grain approaches 2000 μ m.Illustrate that the Zai Jiewen district adds crystal seed crystallisation process can be controlled to low degree of supersaturation zone, be conducive to control the number of nucleus, more be conducive to the growth of crystal.

Comparative Examples 4

Condition is with embodiment 8, adds the above crystal seed of 80 orders, because seed particles is too thin, dissolved very soon, and do not add coming to the same thing of crystal seed.

Embodiment 9

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again the 130g n-heptane solution, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 56 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 35 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 121g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 90%.The centrifuge mother liquor normal heptane solvent can be carried out recycling.120g hexanolactam crystal is turned back in the 500ml there-necked flask, add the 120g n-heptane solution, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.96% ε-caprolactam crystal and normal heptane washing mother liquor, yield reaches 95% left and right.The normal heptane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 126s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 100g after the normal heptane washing, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 40000s, E value<0.04, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 10

As described in Example 1, get the crude epsi-caprolactam that 65g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds again 130g hexanaphthene and normal heptane, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 54 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 45 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 50.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 75%.The mixture of centrifuge mother liquor hexanaphthene and normal heptane can carry out recycling.50g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds 50g hexanaphthene and normal heptane, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain 99.98% ε-caprolactam crystal and washing mother liquor, yield reaches 94% left and right.The mixture cleaning solvent of hexanaphthene and normal heptane is reclaimed.The PM value of the ε-caprolactam obtained is 150s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 40g after the mixture washing of hexanaphthene and normal heptane, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 11

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again the 130g n-heptane solution, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 57 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 10g6～10 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 45 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 106g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 75%.The centrifuge mother liquor normal heptane solvent can be carried out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add 100g normal heptane cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.96% ε-caprolactam crystal and normal heptane washing mother liquor, yield reaches 95% left and right.The normal heptane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 120s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 80g after the normal heptane washing, be added in the 500ml reactor, add water 200g, then add 0.4g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7a tm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 12

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the hexanaphthene: octane-iso=1:5) that adds again 130g hexanaphthene and octane-iso, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 56 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 113.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 85% left and right.The mixture of centrifuge mother liquor hexanaphthene and octane-iso can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the hexanaphthene: octane-iso=1:5) that adds 80g hexanaphthene and octane-iso, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain 99.96% ε-caprolactam crystal and washing mother liquor, yield reaches 72% left and right.The mixture cleaning solvent of hexanaphthene and octane-iso is reclaimed.The PM value of the ε-caprolactam obtained is 120s, E value<0.8.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 80g after the mixture washing of hexanaphthene and octane-iso, be added in the 500ml reactor, add water 200g, then add 0.4g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7a tm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 36000s, E value<0.05, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 13

As described in Example 1, get the crude epsi-caprolactam that 90g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds again 130g hexanaphthene and normal heptane, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53.5 ℃ of left and right from 70 ℃, adds 5.2g40～60 purpose hexanolactam crystal in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 74.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 78% left and right.The mixture of centrifuge mother liquor hexanaphthene and normal heptane can carry out recycling.70g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds 90g hexanaphthene and normal heptane, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain 99.98% ε-caprolactam crystal and washing mother liquor, yield reaches 92% left and right.The mixture cleaning solvent of hexanaphthene and normal heptane is reclaimed.The PM value of the ε-caprolactam obtained is 180s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 40g after the mixture washing of hexanaphthene and normal heptane, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 44000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 14

As described in Example 1, get the crude epsi-caprolactam that 70g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds again 260g hexanaphthene and normal heptane, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53.5 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 8.0g16～10 mesh sieve mesh numbers in there-necked flask, at 54～60 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 42 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 3.Stop stirring, take out there-necked flask, centrifugation, obtain 59g99.96% hexanolactam crystal and centrifuge mother liquor, and yield reaches 76% left and right.The mixture of centrifuge mother liquor hexanaphthene and normal heptane can carry out recycling.50g hexanolactam crystal is turned back in the 500ml there-necked flask, mixture (the hexanaphthene: normal heptane=1:3) that adds 65g hexanaphthene and normal heptane, at room temperature agitator treating is 10 minutes, and then carry out centrifugation, obtain 99.99% ε-caprolactam crystal and washing mother liquor, yield reaches 92% left and right.The mixture cleaning solvent of hexanaphthene and normal heptane is reclaimed.The PM value of the ε-caprolactam obtained is 240s, E value<0.6.

Hydrogenation reaction: get the 99.99% hexanolactam crystal of 40g after the mixture washing of hexanaphthene and normal heptane, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 46000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 15

Cyclohexanone-Oxime Gas Phase Beckmann Rearrangement is carried out in the 80ml fixed-bed reactor, the internal diameter of reactor is 28mm, the molecular sieve catalyst loadings of high silica alumina ratio MF I structure is 9.45g(Φ 1.8mm bar shaped catalyst), reaction pressure 0.1MPa, 365 ℃-385 ℃ of catalyst bed reaction temperature, carrier gas flux is 3.0L/gcat/hr, and cyclohexanone-oxime WHSV is 2h ^-1, the dividing potential drop scope of mixture: cyclohexanone-oxime 5.5kPa-11.6kPa, methyl alcohol (solvent) 36.9kPa-70.6kPa, nitrogen (carrier gas) 19.4kPa-52.6kPa.Reaction product is collected by-5 ° of C ethylene glycol solution circulating coolings, obtains the reaction product containing ε-caprolactam.

At first adopt the method for simple distillation to be distilled this reaction mixture, remove methyl alcohol, lower-boiling impurity and high-boiling-point impurity, finally obtain crude epsi-caprolactam.On Agilent company 6890 type gas chromatographs, (hydrogen flame ionization sensor, PEG20M capillary chromatographic column, column length 50m) analyzed crude epsi-caprolactam, and its chief component is: 99.2% ε-caprolactam.

Get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, then add 130g n-propylcarbinyl chloride recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.5g16～40 mesh sieve mesh numbers in there-necked flask, at 50～57 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 45 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve is shown in the curve 2 of Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 106.6g99.96% hexanolactam crystal and centrifuge mother liquor ether, and yield reaches 81%.Centrifuge mother liquor n-propylcarbinyl chloride solvent can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add 100g n-propylcarbinyl chloride cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.97% ε-caprolactam crystal and n-propylcarbinyl chloride cleaning solvent, yield reaches 94.5% left and right.The n-propylcarbinyl chloride cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 160s, E value<0.5.

Hydrogenation reaction: get the 99.97% hexanolactam crystal of 100g after the n-propylcarbinyl chloride solvent wash, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Comparative Examples 5

This Comparative Examples illustrates under same crystallization condition, impact crystal size distributed without crystal seed.

Condition is with embodiment 15, and difference is not add crystal seed.Resulting caprolactam product quality, the PM value is 46000s, E value<0.03.This quality product is no problem, but particle is thin, there is no intensity, industrial, is difficult to carry out the solid-liquid separation.

The crystal size distribution curve of products obtained therefrom is shown in the curve 1 of Fig. 4.

Find out from the crystal size distribution curve of Fig. 4, adding with not add the crystal size distributional difference obtained under the crystal seed condition obvious.In Comparative Examples 5, do not add the most probable of crystal grain after seeded crystallization and be distributed in 650 μ m places, and embodiment 15 most probable of crystal size after adding seeded crystallization is distributed in 950 μ m places, crystal grain obviously increases, most probable distributes has increased by 300 μ m, and wherein large crystal grain is greater than 2000 μ m.Illustrate that the Zai Jiewen district adds crystal seed crystallisation process can be controlled to low degree of supersaturation zone, be conducive to control the number of nucleus, more be conducive to the growth of crystal.

Comparative Examples 6

Condition is with embodiment 15, adds the above crystal seed of 80 orders, because seed particles is too thin, dissolved very soon, and do not add coming to the same thing of crystal seed.

Embodiment 16

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again the different chlorobutane recrystallisation solvent of 130g, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 53 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 35 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 114g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 86%.The different chlorobutane solvent of centrifuge mother liquor can carry out recycling.110g hexanolactam crystal is turned back in the 500ml there-necked flask, add the different chlorobutane cleaning solvent of 110g, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.96% ε-caprolactam crystal and washing mother liquor, yield reaches 95% left and right.Different chlorobutane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 126s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 100g after different chlorobutane solvent wash, be added in the 500ml reactor, add water 250g, then add 0.5g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 40000s, E value<0.04, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 17

As described in Example 1, get the crude epsi-caprolactam that 65g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g trichloromethane recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 52 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 43 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 52g99.94% hexanolactam crystal and centrifuge mother liquor, and yield reaches 79%.Centrifuge mother liquor trichloromethane solvent can carry out recycling.50g hexanolactam crystal is turned back in the 500ml there-necked flask, add 50g trichloromethane cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.96% ε-caprolactam crystal and washing mother liquor, and yield reaches 92% left and right.The trichloromethane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 120s, E value<0.7.

Hydrogenation reaction: get 99.96% hexanolactam crystal after 40g trichloromethane solvent wash, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 36000s, E value<0.05, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 18

As described in Example 1, get the crude epsi-caprolactam that 130g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again the different chlorobutane recrystallisation solvent of 130g, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 54 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 10g6～10 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 44 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 113g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 81%.The different chlorobutane solvent of centrifuge mother liquor can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add the different chlorobutane cleaning solvent of 80g, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.96% ε-caprolactam crystal and washing mother liquor, and yield reaches 95% left and right.Different chlorobutane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 150s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 80g after different chlorobutane solvent wash, be added in the 500ml reactor, add water 200g, then add 0.4g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 19

As described in Example 1, get the crude epsi-caprolactam that 90g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g n-propylcarbinyl chloride recrystallisation solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 52 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 2.6g16～40 mesh sieve mesh numbers in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 113.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 84% left and right.Centrifuge mother liquor n-propylcarbinyl chloride solvent can carry out recycling.100g hexanolactam crystal is turned back in the 500ml there-necked flask, add 80g n-propylcarbinyl chloride cleaning solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtain 99.97% ε-caprolactam crystal and washing mother liquor, yield reaches 90% left and right.N-propylcarbinyl chloride solvent wash solvent is reclaimed.The PM value of the ε-caprolactam obtained is 150s, E value<0.8.

Hydrogenation reaction: get the 99.97% hexanolactam crystal of 80g after the n-propylcarbinyl chloride solvent wash, be added in the 500ml reactor, add water 200g, then add 0.4g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 42000s, E value<0.04, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 20

As described in Example 1, get the crude epsi-caprolactam that 90g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again 130g trichloromethane solvent, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 51.5 ℃ of left and right from 70 ℃, adds 5.2g40～60 purpose hexanolactam crystal in there-necked flask, at 50～58 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 40 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 4 similar characteristics with Fig. 2.Stop stirring, take out there-necked flask, centrifugation, obtain 76.3g99.95% hexanolactam crystal and centrifuge mother liquor, and yield reaches 80% left and right.Centrifuge mother liquor trichloromethane solvent can carry out recycling.70g hexanolactam crystal is turned back in the 500ml there-necked flask, add 70g trichloromethane solvent, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.96% ε-caprolactam crystal and washing mother liquor, and yield reaches 92% left and right.Trichloromethane solvent wash solvent is reclaimed.The PM value of the ε-caprolactam obtained is 150s, E value<0.6.

Hydrogenation reaction: get the 99.96% hexanolactam crystal of 60g after the trichloromethane solvent wash, be added in the 300ml reactor, add water 150g, then add 0.3g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 40000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Embodiment 21

As described in Example 1, get the crude epsi-caprolactam that 70g obtains by above-mentioned simple distillation method, add in the 500ml there-necked flask, add again the different chlorobutane recrystallisation solvent of 260g, be heated to 60～70 ℃, stir 10 minutes, ε-caprolactam is dissolved in this solvent fully.Continue coolingly while stirring, temperature is cooled to 51 ℃ of left and right from 70 ℃, adds the hexanolactam crystal of 8.0g6～10 mesh sieve mesh numbers in there-necked flask, at 50～56 ℃, maintains 15 minutes, and stirring velocity remains unchanged, and has the macrobead hexanolactam to generate; Continue coolingly while stirring, to 35 ℃ of left and right, the macrobead hexanolactam is separated out fully, and gained crystal size distribution curve has curve 2 similar characteristics with Fig. 4.Stop stirring, take out there-necked flask, centrifugation, obtain 67.1g99.96% hexanolactam crystal and centrifuge mother liquor, and yield reaches 86% left and right.The different chlorobutane solvent of centrifuge mother liquor can carry out recycling.50g hexanolactam crystal is turned back in the 500ml there-necked flask, add the different chlorobutane cleaning solvent of 65g, at room temperature agitator treating is 10 minutes, and then carries out centrifugation, obtains 99.98% ε-caprolactam crystal and washing mother liquor, and yield reaches 94% left and right.Different chlorobutane cleaning solvent is reclaimed.The PM value of the ε-caprolactam obtained is 180s, E value<0.6.

Hydrogenation reaction: get the 99.98% hexanolactam crystal of 40g after different chlorobutane solvent wash, be added in the 200ml reactor, add water 100g, then add 0.2g amorphous nickel hydrogenation catalyst (the industrial trade mark is SRNA-4, and Hunan Jianchang Petrochemical Co., Ltd produces), be heated to 90 ℃ of left and right, pass into hydrogen, hydrogen flowing quantity is controlled at 0.6L/min, and reaction pressure maintains 7atm, the epsilon-caprolactam water solution that crystallization is gone out contacts with hydrogen, reacts 1 hour.Triple effect evaporation, and underpressure distillation under about 1mmHg condition, obtain caprolactam product.The caprolactam product quality that analysis obtains, the PM value is 45000s, E value<0.03, be purity at the hexanolactam finished product more than 99.995%, meet the Industrial products requirement.

Claims (49)

1. the crystal refining method of a hexanolactam, it is characterized in that the method comprises the step that the solution containing the thick product of ε-caprolactam is contacted to processing with crystal seed, said contact is processed and is being carried out containing in the solution De Jiewen district of the thick product of ε-caprolactam, and said crystal seed is 2～80 purpose hexanolactam particles.

2. according to the method for claim 1, wherein, said containing in the solution of the thick product of ε-caprolactam, the part by weight of the thick product of ε-caprolactam and organic solvent is 1: 1～10, said crystal seed accounts for 1～15 heavy % of the thick product of ε-caprolactam, and said contact is processed and carried out in 45～62 ℃ of temperature in said Jie Wen district.

3. according to the method for claim 1 or 2, wherein, the thick product of said ε-caprolactam is that the zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtain after distilling out reaction solvent.

4. according to the method for claim 1 or 2, wherein, in the thick product of said ε-caprolactam, hexanolactam purity is 99.0～99.6 heavy %.

5. the crystal refining method of a hexanolactam, it is characterized in that the method comprises the step that the solution containing the thick product of ε-caprolactam is contacted with crystal seed, said contact is being carried out containing in the solution De Jiewen district of the thick product of ε-caprolactam, said crystal seed is 2～80 purpose hexanolactam particles, the ethereal solution that wherein solution of the thick product of said ε-caprolactam is the thick product of ε-caprolactam, said ether is selected from one or more in linear, branched chain ether, diether, alcohol ether or alkene ether, and said crystal seed is 2～80 purpose hexanolactam particles.

6. according to the method for claim 5, it is characterized in that the method comprises the thick product of ε-caprolactam is dissolved in said ether, obtain the ethereal solution of the thick product of ε-caprolactam; Carry out thermostatical crystallization with the ethereal solution contact of the thick product of ε-caprolactam of 45～62 ℃ of temperature in said crystal seed Yu Jiewen district again, obtain the hexanolactam crystal grain, then, through solid-liquid separation, reclaim the hexanolactam crystal.

7. according to the method for claim 5 or 6, wherein, in the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1: 1～10.

8. according to the method for claim 7, wherein, the part by weight of the thick product of said ε-caprolactam and ether is 1: 1.2～8.

9. according to the method for claim 8, wherein, the part by weight of the thick product of said ε-caprolactam and ether is 1: 2～5.

10. according to the method for one of claim 5～9, wherein, the thick product of said ε-caprolactam is that the zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtain after distilling out reaction solvent.

11., according to the method for one of claim 5～9, wherein, in the thick product of said ε-caprolactam, hexanolactam purity is 99.0～99.6 heavy %.

12., according to the method for claim 5 or 6, wherein, said crystal seed is 10～60 purpose hexanolactam particles.

13., according to the method for claim 5 or 6, wherein, said crystal seed is 20～40 purpose hexanolactam particles.

14., according to the method for claim 5 or 6, wherein, said crystal seed accounts for 1～15 heavy % of the thick product of ε-caprolactam.

15. according to the method for claim 5 or 6, wherein, said crystal seed is 40～60 purpose hexanolactam particles, accounts for 1～5 heavy % of the thick product of ε-caprolactam.

16., according to the method for claim 15, wherein, said crystal seed accounts for 2～4 heavy % of the thick product of ε-caprolactam.

17. according to the method for claim 5 or 6, wherein, said crystal seed is 20～40 purpose hexanolactam particles, accounts for 5～10 heavy % of the thick product of ε-caprolactam.

18., according to the method for claim 17, wherein, said crystal seed accounts for 6～9 heavy % of the thick product of ε-caprolactam.

19. according to the process of claim 1 wherein, said crystal seed is 6～20 purpose hexanolactam particles, accounts for 10～15 heavy % of the thick product of ε-caprolactam.

20., according to the method for claim 19, wherein, said crystal seed accounts for 11～14 heavy % of the thick product of ε-caprolactam.

21., according to the method for claim 5, wherein, said ether has the boiling range of 30～150 ℃.

22., according to the method for claim 21, wherein, said ether has the boiling range of 50～100 ℃.

23., according to the method for claim 22, wherein, said ether has the boiling range of 60～90 ℃.

24., according to the method for claim 21, wherein, said ether is selected from one or more in ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

25., according to the method for claim 5, wherein, the said step that will contact with crystal seed containing the solution of the thick product of ε-caprolactam is carried out repeatedly.

26. the preparation method of a hexanolactam, comprise that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of the thick product of ε-caprolactam through distillation, the step of crystallization, solvent wash after crystallization, separate the step that obtains the ε-caprolactam crystal, at hydrogenation catalyst, exist, the step that ε-caprolactam is contacted with hydrogen, and the step that finally obtains the ε-caprolactam finished product, it is characterized in that in the step of said crystallization, comprise the process that crystal seed is contacted with the solution of the thick product of ε-caprolactam in the Jie Wen district, said crystal seed is 2～80 purpose hexanolactam particles.

27. the method according to claim 26, wherein, said containing in the solution of the thick product of ε-caprolactam, the part by weight of the thick product of ε-caprolactam and organic solvent is 1: 1～10, said crystal seed accounts for 1～15 heavy % of the thick product of ε-caprolactam, and said contact is carried out in 45～62 ℃ of temperature in said Jie Wen district.

28. according to the method for claim 26 or 27, wherein, the thick product of said ε-caprolactam is that the zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtain after distilling out reaction solvent.

29., according to the method for claim 26 or 27, wherein, in the thick product of said ε-caprolactam, hexanolactam purity is 99.0～99.6 heavy %.

30. the preparation method of a hexanolactam, comprise that ε-caprolactam that Beckmann rearrangement is obtained and the mixed solution of reaction solvent obtain the step of the thick product of ε-caprolactam through distillation, the step of crystallization, solvent wash after crystallization, separate the step that obtains the ε-caprolactam crystal, at hydrogenation catalyst, exist, the step that ε-caprolactam is contacted with hydrogen, and the step that finally obtains the ε-caprolactam finished product, it is characterized in that in the step of said crystallization, comprise the process that crystal seed is contacted with the ethereal solution of the thick product of ε-caprolactam in the Jie Wen district, wherein said ether is selected from the straight chain aliphatic hydrocarbon, one or more in chain aliphatic hydrocarbon and cycloaliphatic hydrocarbon, said crystal seed is 2～80 purpose hexanolactam particles.

31., according to the method for claim 30, wherein, in the ethereal solution of the thick product of said ε-caprolactam, the part by weight of the thick product of ε-caprolactam and ether is 1: 1～10.

32., according to the method for claim 31, wherein, the part by weight of the thick product of said ε-caprolactam and ether is 1: 1.2～8.

33., according to the method for claim 32, wherein, the part by weight of the thick product of said ε-caprolactam and ether is 1: 2～5.

34. according to the method for claim 30, wherein, the thick product of said ε-caprolactam is that the zeolite [molecular sieve by cyclohexanone-oxime and MFI topology carries out vapor phase beckmann rearrangement reaction, then obtain after distilling out reaction solvent.

35., according to the method for claim 30, wherein, in the thick product of said ε-caprolactam, hexanolactam purity is 99.0～99.6 heavy %.

36., according to the method for claim 30, wherein, said crystal seed is 20～60 purpose hexanolactam particles.

37., according to the method for claim 30, wherein, said crystal seed is 20～40 purpose hexanolactam particles.

38., according to the method for claim 30, wherein, said crystal seed accounts for 1～15 heavy % of the thick product of ε-caprolactam.

39. according to the method for claim 30, wherein, said crystal seed is 40～60 purpose hexanolactam particles, accounts for 1～5 heavy % of the thick product of ε-caprolactam.

40., according to the method for claim 39, wherein, said crystal seed accounts for 2～4 heavy % of the thick product of ε-caprolactam.

41. according to the method for claim 39, wherein, said crystal seed is 20～40 purpose hexanolactam particles, accounts for 5～10 heavy % of the thick product of ε-caprolactam.

42., according to the method for claim 41, wherein, said crystal seed accounts for 6～9 heavy % of the thick product of ε-caprolactam.

43. according to the method for claim 30, wherein, said crystal seed is 6～20 purpose hexanolactam particles, accounts for 10～15 heavy % of the thick product of ε-caprolactam.

44., according to the method for claim 43, wherein, said crystal seed accounts for 11～14 heavy % of the thick product of ε-caprolactam.

45., according to the method for claim 30, wherein, said ether has the boiling range of 30～150 ℃.

46., according to the method for claim 45, wherein, said ether has the boiling range of 50～100 ℃.

47., according to the method for claim 46, wherein, said ether has the boiling range of 60～90 ℃.

48., according to the method for claim 45, wherein, said ether is selected from one or more in ether, positive propyl ether, isopropyl ether, n-butyl ether, methyl-n-butyl ether, b-butyl ether, glycol dimethyl ether, Vinyl Ether, methyl tertiary butyl ether, Ethyl Tertisry Butyl Ether.

49., according to the method for claim 30, wherein, said crystal seed is carried out repeatedly with the process that the ethereal solution of the thick product of ε-caprolactam in the Jie Wen district contacts.

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