CN111825540A

CN111825540A - Method for preparing 2-alkyl anthraquinone by catalytic oxidation of 2-alkyl anthracene obtained by alkylation of anthracene

Info

Publication number: CN111825540A
Application number: CN201910300813.5A
Authority: CN
Inventors: 郑博; 费建奇; 潘智勇; 朱振兴; 毛俊义; 宗保宁
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-04-15
Filing date: 2019-04-15
Publication date: 2020-10-27
Anticipated expiration: 2039-04-15
Also published as: CN111825540B

Abstract

The invention relates to the field of preparation of 2-alkyl anthraquinone, and particularly discloses a method for preparing 2-alkyl anthraquinone by performing catalytic oxidation on 2-alkyl anthracene obtained by alkylating anthracene, which comprises the following steps: contacting anthracene with an alkylating agent for alkylation reaction to prepare a reaction product containing alkyl anthracene, wherein the alkylating reaction solvent is a combination of a solvent A with a dielectric constant of 1-10 at 20 ℃ and a solvent B with a dielectric constant of more than 10 and less than or equal to 50 at 20 ℃; separating anthracene from a reaction product containing alkyl anthracene through melt crystallization and separating 2-alkyl anthracene through distillation; 2-alkyl anthracene is contacted with an oxidant to carry out oxidation reaction. The alkylation combined solvent and the catalyst adopted in the invention ensure that the selectivity of the 2-alkyl anthracene is high; the separation method can obviously reduce the separation operation difficulty and has high product purity; the adopted oxidation system is simple and efficient, the catalyst is low in cost and easy to recover.

Description

Method for preparing 2-alkyl anthraquinone by catalytic oxidation of 2-alkyl anthracene obtained by alkylation of anthracene

Technical Field

The invention relates to a preparation method of an organic matter, in particular to a method for preparing 2-alkyl anthraquinone by catalyzing and oxidizing 2-alkyl anthracene obtained by alkylation of anthracene.

Background

Hydrogen peroxide is an important green basic chemical, has high industrial relevance, and has become the first major country for hydrogen peroxide production since 2008, and the consumption amount is over 1000 million t/a (calculated by 27.5%) in 2015. At present, the technology for producing hydrogen peroxide at home and abroad is mainly an anthraquinone method. The 2-alkyl anthraquinone in the process is used as a 'carrier' of the process, and the quality and the yield of the hydrogen peroxide are directly influenced. The phthalic anhydride process is the primary method for producing 2-alkylanthraquinones, but this process suffers from serious contamination problems. 1.76 tons of anhydrous AlCl is required to be added for producing 1 ton of 2-ethyl anthraquinone₃And 4.2 tons of fuming H₂SO₄(20%) and the recovery of both is difficult. Therefore, it is very important to develop a green production process of 2-alkylanthraquinone from the viewpoint of environmental protection and clean production.

US 4255343 discloses a method for synthesizing 2-tert-amyl anthracene, which comprises uniformly mixing anthracene, trichlorobenzene and methanesulfonic acid under certain temperature and pressure conditions, and introducing olefin into the system to perform alkylation reaction with anthracene. The solid product was mainly the remaining anthracene and the series of alkyl anthracene products, with 42 wt% anthracene and 47 wt% 2-alkyl anthracene, with the remainder being anthracene disubstituted product and other by-products.

TW 200623958 discloses anthracene catalyzed by ionic liquidAlkylation process, which refers to an alkylation reaction with a catalytic system comprising a mixture of 60 to 93.7% by weight of ionic liquid and 1 to 8% by weight of aluminium chloride. In the examples, BmimPF₆As solvent, and adding proper AlCl₃When the alkylation reaction of anthracene and tert-butyl chloride is catalyzed at 70 ℃, the yield of the product 2, 6-tert-butyl anthracene is 90%.

Perezromero et al used H₂O₂Oxidizing anthracene or 2-alkyl anthracene to prepare anthraquinone with Cu-containing Tp as catalyst^xCu (NCMe), after reacting for 2h at 80 ℃, the conversion rate of anthracene is 95%, and the selectivity of anthraquinone is 98%.

The use of H is disclosed in US 3953482₂O₂A process for preparing 2-alkylanthraquinone by oxidizing 2-alkylanthraquinone. Using fatty alcohol as solvent, concentrated hydrochloric acid as catalyst and H₂O₂(60%) is an oxidant, and the reaction is carried out for 60min at the normal pressure of 40-100 ℃, so that a better reaction effect can be obtained. The conversion rate of the 2-pentylanthracene is 94 percent, and the selectivity of the 2-pentylanthraquinone is as high as 97 percent.

As can be seen, no complete set of process technology for preparing 2-alkylanthraquinone from anthracene is reported at present.

Disclosure of Invention

The invention aims to provide a novel method for preparing 2-alkyl anthraquinone by catalyzing and oxidizing 2-alkyl anthracene obtained by alkylation of anthracene based on the prior art, namely an integral process for preparing 2-alkyl anthraquinone by alkylation reaction-separation of anthracene serving as a raw material and preparing 2-alkyl anthracene by oxidation reaction of the 2-alkyl anthracene.

The invention provides a method for preparing 2-alkyl anthraquinone by catalyzing and oxidizing 2-alkyl anthracene obtained by alkylating anthracene, wherein the preparation method comprises the following steps:

(1) contacting anthracene with an alkylating agent under alkylation conditions in the presence of an alkylation reaction solvent and a catalyst to carry out alkylation reaction to prepare a reaction product containing alkyl anthracene, wherein the alkylation reaction solvent is a combination of a solvent A with a dielectric constant of 1-10 at 20 ℃ and a solvent B with a dielectric constant of more than 10 and less than or equal to 50 at 20 ℃;

(2) separating the reaction product containing alkyl anthracene obtained from step (1), the separation method comprising: melting crystallization separation of anthracene and distillation separation of 2-alkyl anthracene;

(3) contacting the 2-alkyl anthracene obtained in the step (2) with an oxidizing agent, which is hydrogen peroxide, under oxidizing conditions and in the presence of an oxidizing reaction solvent and a catalyst, wherein the catalyst is one or more selected from the group consisting of an oxide of an alkaline earth metal, a hydroxide of an alkaline earth metal, an oxygen-containing compound of a transition metal, and an oxygen-containing compound of a lanthanide metal.

The whole technical route of preparing the 2-alkyl anthraquinone by the 2-alkyl anthracene obtained by the alkylation of the anthracene and then carrying out catalytic oxidation is reasonable and feasible, and opens up a new direction for the green preparation of the 2-alkyl anthraquinone. According to the method provided by the invention, the combined solvent is adopted as a reaction medium in the alkylation reaction process, so that the property of the reaction solvent can be effectively regulated and controlled, the solvation effect is exerted, the solubility of anthracene is improved, and the alkylation reaction is promoted to be carried out. The method provided by the invention can obviously reduce the operation difficulty in the separation process of the anthracene-alkyl anthracene product and improve the purity and the total yield of the intermediate target product 2-alkyl anthracene by a melt crystallization-distillation coupling separation technology.

In the method provided by the invention, the constructed 2-alkyl anthracene catalytic oxidation system is simple and efficient, the catalyst is low in separation and recovery difficulty and free from corrosivity, the equipment investment and the post-treatment cost of the oxidation waste liquid are reduced, and the conversion of the 2-alkyl anthracene can be effectively realized.

Preferably, in the method provided by the invention, a combined solvent system is adopted in the reaction process of preparing the anthraquinone by oxidizing the 2-alkyl anthracene, so that the oxidation reaction of the 2-alkyl anthracene can be enhanced by adjusting the property of the solvent, and the reaction selectivity and the product yield are improved.

In addition, the method provided by the invention also has the advantages of simple process, high efficiency and small pollution.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a flow diagram of one embodiment of a process for preparing 2-alkylanthraquinones by alkylating anthracene to 2-alkylanthraanthracene and then catalytically oxidizing the 2-alkylanthraquinone according to the present invention;

FIG. 2 is a diagram of an embodiment of the present invention for the isolation of an anthracene alkylation product, melt crystallization-multi-step vacuum distillation coupling process;

FIG. 3 is a diagram of an embodiment of the present invention for the isolation of an anthracene alkylation product, melt crystallization-multi-step vacuum distillation coupling process;

FIG. 4 is a flow diagram of the melt crystallization step in the present invention providing for the isolation of the anthracene alkylation product, melt crystallization-vacuum distillation process.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, 2-alkylanthraquinone means 2-alkyl-9, 10-anthraquinone, hereinafter referred to as 2-alkylanthraquinone.

According to the invention, the method for preparing 2-alkyl anthraquinone by catalytic oxidation of 2-alkyl anthracene obtained by anthracene alkylation comprises the following steps:

According to the invention, the anthracene ring structure-containing substance in the reaction product obtained in step (1) comprises the remaining anthracene, 2-alkyl anthracene and other series alkyl anthracene products. It is well known to those skilled in the art that if the starting anthracene is not completely converted, the reaction product will also contain residual anthracene. If the alkyl anthracene is not a single species, the alkyl anthracene may also be a mixture. Therefore, the production of alkyl anthracene-containing reaction products from a starting anthracene typically contains anthracene, 2-alkyl anthracene, and other series of alkyl anthracene products.

According to the present invention, as shown in fig. 1, the method for producing a reaction product containing an alkyl anthracene from anthracene in step (1) includes: the alkylation reaction is carried out by contacting anthracene with an alkylating agent under alkylation conditions and in the presence of an alkylation solvent and a catalyst.

The mode of contacting anthracene with an alkylating agent and a catalyst according to the present invention can be any of various modes capable of producing alkyl anthracene by alkylation of anthracene. Preferably, for more complete reaction, the contacting is carried out in the following manner: the raw material liquid containing anthracene, catalyst and alkylation reaction solvent is contacted with alkylation reagent to make alkylation reaction. Specifically, in order to ensure better alkylation reaction, the anthracene, the catalyst and the alkylation reaction solvent are prepared into a raw material solution of the anthracene-catalyst-alkylation reaction solvent, and then an alkylation reagent is added for alkylation reaction. Preferably, the preparation temperature of the raw material liquid of the anthracene-catalyst-alkylation reaction solvent is 100-250 ℃, more preferably 120-200 ℃.

The inventors of the present invention have found that, in the alkylation reaction in step (1), a solvent a having a dielectric constant of 1 to 10 at 20 ℃ and a solvent B having a dielectric constant of more than 10 to 50 or less at 20 ℃ is used as the alkylation reaction solvent, and that the solvent properties can be specifically controlled, whereby the dissolution of the starting material anthracene and the occurrence of the alkylation reaction can be enhanced and the conversion of anthracene can be enhanced by the solvation.

According to the invention, preferably, the solvent A is C₆Above, more preferably C₆-C₁₂One or more of paraffins, naphthenes and aromatics; wherein the aromatic hydrocarbon is substituted or unsubstituted, preferably one or more of monobasic or polybasic substituted substances of benzene, more preferably one or more of polybasic substituted substances of benzene, and the substituted group is preferably C₁-C₄And one or more of an alkyl group and a halogen element. Further preferably, the solvent A is one or more of polyalkyl substituents of benzene, and most preferably, the solvent A is one or more selected from 1,3, 5-trimethylbenzene, 1,2,3, 5-tetramethylbenzene, 1,3,4, 5-tetramethylbenzene, 1,3,5, 6-tetramethylbenzene, and 2,3,5, 6-tetramethylbenzene.

According to the invention, the solvent B is preferably an N-alkyl-substituted amide in which the number of alkyl substituents is from 1 to 2 and each alkyl substituent is independently C₁-C₄Alkyl groups of (a); more preferably, the solvent B is selected from one or more of N, N-dimethylformamide, N-dimethylacetamide and N, N-dimethylpropionamide, and most preferably, the solvent B is N, N-dimethylformamide.

According to the present invention, the alkylation reaction solvent of step (1) can achieve the object of the present invention as long as it is a combination of solvent A and solvent B, but in order to better achieve the object of the present invention of enhancing the alkylation reaction by controlling the solvent properties, the volume ratio of solvent A to solvent B is 0.01 to 100, more preferably 0.1 to 10.

According to the present invention, in the step (1), the amount of the alkylation reaction solvent is not particularly limited, and the amount of the alkylation reaction solvent may be used so long as it is ensured that the anthracene is sufficiently dissolved to provide a good reaction medium. Preferably, the anthracene is present in an amount of from 5 to 60 weight percent, preferably from 8 to 50 weight percent, based on the total weight of anthracene and alkylation reaction solvent.

According to the present invention, in step (1), the anthracene alkylation reaction may be carried out under other conditions, in addition to the alkylation reaction solvent being the combination solvent provided herein, in a manner conventional in the art.

According to the present invention, in step (1), the alkylating agent may be any alkylating agent known to those skilled in the art capable of introducing an alkyl group into an anthracycline to prepare an alkyl anthracene, for example, the alkylating agent may be one or more of an olefin, an alcohol, a halogenated hydrocarbon, and an ether having 2 to 8 carbon atoms, preferably one or more of an olefin, an alcohol, a halogenated hydrocarbon, and an ether having 4 to 6 carbon atoms, and more preferably a monoolefin having 4 to 6 carbon atoms.

According to the invention, in step (1), the alkylating agent is used in an amount that enables the introduction of alkyl groups into the anthracycline to produce alkyl anthracenes, preferably in a molar ratio of anthracene to alkylating agent of from 0.2:1 to 20:1, more preferably from 0.5:1 to 5: 1.

According to the present invention, in step (1), the alkylation reaction conditions generally comprise: the reaction temperature can be 100-250 ℃, preferably 120-200 ℃; the reaction time can be 0.01-48h, preferably 0.5-24 h; the reaction pressure may be from 0 to 1MPa, preferably from 0.05 to 0.5 MPa.

According to the present invention, in step (1), in order to enable the alkylation reaction to be more easily performed, the alkylation reaction is performed in the presence of a catalyst. In particular, the catalyst can be any form and kind of acid catalyst capable of catalyzing the alkylation of anthracene, for example, the catalyst is a solid acid catalyst.

Wherein the solid acid comprises zeolite and zeolite-like catalyst, clay, metal oxide and metal mixed oxide, supported acid, sulfated oxide, layered transition metal oxide, metal salt, heteropoly acid and resin catalyst, and the solid acid is preferably selected from one or more of zeolite-like catalyst, supported acid, heteropoly acid and resin catalyst. For example, for zeolite-based catalysts, the solid acid catalyst contains an active molecular sieve and a binder. The content of the active molecular sieve and the binder in the solid acid catalyst is not particularly limited, so long as the amount of the binder is sufficient to form the active molecular sieve and have a certain strength, and the content of the active molecular sieve is sufficient to realize a catalytic effect. Generally, the active molecular sieve may be present in an amount of 1 to 99 wt% and the binder may be present in an amount of 1 to 99 wt%, based on the total weight of the solid acid catalyst. From the viewpoint of balancing the strength and catalytic activity of the catalyst, the content of the active molecular sieve is 30 to 95 mass% and the content of the binder is 5 to 70 mass% based on the total weight of the solid acid catalyst.

The types of the active molecular sieve and the binder are not particularly limited in the present invention, and may be conventionally selected in the art. Generally, the active molecular sieve may be selected from one or more of an X molecular sieve, a Y molecular sieve, a beta molecular sieve, a ZSM-5 molecular sieve, a SAPO molecular sieve and a mesoporous molecular sieve, preferably a Y-type molecular sieve. The binder may be an inorganic binder or an organic binder, preferably an inorganic binder. The inorganic binder may be a refractory inorganic oxide and/or silicate, for example the binder may be one or more of alumina, silica, titania, magnesia, zirconia, thoria, beryllia and clay, more preferably alumina.

The catalyst may also be used in an amount of 0.01 to 50 wt%, preferably 0.5 to 30 wt%, based on the total weight of the raw material solution containing anthracene, the alkylation reaction solvent and the catalyst, with reference to amounts conventionally used in the art.

In the present invention, the shape of the solid acid catalyst is not particularly limited, and may be selected conventionally in the art. For example, it may be spherical, strip-shaped, annular, clover-shaped, etc., and spherical particles are preferable for convenience of packing, and the particle size of the spherical particles may be in the range of 10 μm to 1000 μm, more preferably 20 to 300 μm.

According to the present invention, the process for preparing alkyl anthracene from raw material anthracene in step (1) requires the use of a catalyst, and the catalyst after reaction may be separated after step (1) and before step (2) by a separation method that is conventional in the art according to the nature of the catalyst.

According to physical analysis, the boiling point of anthracene is 340 ℃, and the alkyl anthracene product and the anthracene homologue have a boiling point difference, and the product can be separated by a reduced pressure distillation technology. But the technical difficulty is that the melting point of anthracene is as high as 215 ℃, anthracene with a high solidifying point is separated by adopting a vacuum distillation technology alone, the operation difficulty is high, once the pipeline has a problem in heat preservation, the phenomenon of blockage is easy to occur, and the continuous and stable operation of the process is seriously influenced. In addition, anthracene is very easily sublimed, and sublimation temperature is difficult to control, and the chance that the pipeline takes place to block up is showing to increase. Thus, it is impractical to use solely vacuum distillation techniques to achieve separation of the anthracene-alkyl anthracene product.

Therefore, the inventors of the present invention propose to separate anthracene and alkyl anthracene products using a melt crystallization-distillation separation method. The alkyl anthracene destroys the high regularity of an anthracene ring structure due to the existence of a side chain substituent group, so that the melting point of an alkyl anthracene product is obviously reduced, for example, the melting point range of a low-carbon alkyl anthracene product (1< the carbon number j1<8 of an alkyl side chain of anthracene) is 130-150 ℃, the melting point range of a high-carbon alkyl anthracene product (7< the carbon number j2<18 of an alkyl side chain of anthracene) is 150-190 ℃, the melting points are obviously lower than the melting point 215 ℃ of anthracene, and a large melting point difference exists between the alkyl anthracene and the anthracene. For this reason, the inventor of the present invention proposes to first use the melt crystallization technique to separate and remove the anthracene which has the highest melting point and is most difficult to separate by crystallization, and then use one or more reduced pressure distillation techniques to further separate the anthracene from the alkyl anthracene mixture with high boiling point according to the difference of the boiling points.

Based on this, according to the present invention, the reaction product containing alkyl anthracene obtained through step (1) contains anthracene and a series of alkyl anthracene products containing 2-alkyl anthracene; the step (2) comprises the following steps:

(2-2) heating the reaction product containing the alkyl anthracene obtained in the step (1) to a molten state, cooling and crystallizing, separating to obtain an anthracene crystal and a feed liquid containing a series of alkyl anthracene products of 2-alkyl anthracene, heating the anthracene crystal for sweating, and separating the sweating liquid and the anthracene crystal;

(2-3) separating 2-alkyl anthracene from a series of alkyl anthracene products containing 2-alkyl anthracene by one or more distillation steps.

According to one embodiment of the present invention, as shown in FIG. 4, the melt crystallization step can be carried out in a melt crystallization system in which the crystalline separation of anthracene from the reaction product mixture can be achieved. The melt crystallization system includes an intermediate melt tank and a melt crystallizer. The melted product containing anthracene and serial alkyl anthracene products heated and melted in the distillation tower is sent into an intermediate melting tank and then is introduced into a melting crystallizer. The apparatus for implementing the melt crystallization process is a melt crystallizer, the crystallization process can be lamellar crystallization or suspension crystallization, and the operation mode can be batch operation or continuous operation, but the invention is not limited to the method, but the batch operation lamellar crystallization mode is more preferable. The temperature increase and decrease in the melt crystallizer is achieved by introducing a heat exchange medium into the melt crystallizer. After the heated and melted material enters the melting crystallizer, the cooling medium is used for cooling, so that the anthracene with a high melting point is crystallized and separated out, and further, the separation of the anthracene and a series of alkyl anthracene products is realized.

According to the present invention, in the melt crystallization step of (2-2), in order to better achieve the crystal separation of anthracene, the melting temperature is controlled to 200-270 ℃, preferably 210-250 ℃.

According to the invention, the melt crystallization process essentially comprises three steps of cooling crystallization, sweating and preferably warming remelting of the anthracene crystals.

According to the present invention, the temperature for cooling crystallization can be 180-210 ℃, preferably 190-200 ℃. In order to better realize the crystal separation of anthracene, the cooling rate of the cooling crystal can be 0.1-10 ℃/h, preferably 0.5-5 ℃/h, and the cooling crystallization time, namely the crystal growth time can be controlled to be 1-5h, preferably 1.5-4 h.

According to the present invention, in order to increase the crystallization rate, in the cooling crystallization process, it is preferable to further include a step of adding seed anthracene, which may be added in an amount according to the details of the cooling crystallization process, and it is further preferable to add the seed anthracene in an amount of 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on the mass of the molten mixture.

According to the present invention, in order to further increase the purity of the crystalline anthracene, it is necessary to further perform a sweating operation on the anthracene crystal. After the crystal layer is formed, the temperature of the crystal layer is slowly close to the equilibrium temperature by controlling the rising rate of the temperature of the crystal layer, and the local crystal containing more impurities is low in melting point due to uneven distribution of the impurities in the crystal layer and can be firstly melted and separated from the crystal in a sweating mode.

According to the present invention, in the melt crystallization step, the temperature increase rate at which the anthracene crystal undergoes sweating is controlled to 0.1 to 8 deg.C/h, preferably 0.2 to 4 deg.C/h, from the viewpoint of further improving the purity of the crystal and the separation accuracy. The temperature raised to the temperature at which sweating stops cannot melt the crystallized anthracene crystal, and therefore, the temperature raised to the temperature at which sweating stops must be lower than the melting temperature of the anthracene crystal, preferably the temperature raised to the temperature at which sweating stops is 210 ℃ or lower, more preferably, the temperature raised to 5 to 15 ℃ higher than the cooling crystallization temperature, and the sweating stops below 210 ℃. The sweating end temperature may be 190-210 deg.C, more preferably 195-205 deg.C, under the principle of following the above-mentioned sweating stop temperature. In order to further increase the purity of the crystalline anthracene, the amount of perspiration can also be controlled so that the amount of perspiration is 5 to 40% by weight, more preferably 10 to 30% by weight, of the mass of the crystal.

According to the present invention, in order to further improve the separation accuracy, the collected sweat is recycled, that is, the sweat is recycled to the melting and crystallizing step, and the melting and cooling crystallization is carried out by heating together with the reaction product containing alkyl anthracene, that is, the mixture containing anthracene and the series of alkyl anthracene products.

According to the invention, after sweating is finished, the temperature of the separated anthracene crystal can be increased to over 215 ℃, and the crystal anthracene is collected and recycled after being completely melted into liquid.

After melt crystallization according to the process of the present invention, the non-crystallized material collected, i.e., the feed solution of the 2-alkyl anthracene-containing series of alkyl anthracene products consisting essentially of the series of alkyl anthracene products (substantially free of anthracene), is collected.

According to the invention, the boiling points of the serial alkyl anthracene products containing 2-alkyl anthracene are all higher than that of anthracene (340 ℃), so that the distillation technology is needed to further realize the purpose of serial alkyl anthracene product separation. Thus, 2-alkyl anthracenes can be separated from a series of alkyl anthracene products containing 2-alkyl anthracenes by one or more distillation steps.

According to the present invention, in the step (2-3), when the alkyl anthracene product of the series containing 2-alkyl anthracene is a mixture of two substances, or a mixture of three or more substances, the boiling point of 2-alkyl anthracene is the lowest or the highest; then a one-step distillation is performed to separate the 2-alkyl anthracene. In the step (2-3), when the serial alkyl anthracene products containing the 2-alkyl anthracene are a mixture of more than three substances, and the boiling point of the 2-alkyl anthracene is between the substance with the highest boiling point and the substance with the lowest boiling point in the mixture; a multi-step distillation is performed.

According to an embodiment of the present invention, in the step (2-3), the multi-step distillation method comprises:

mode 1: as shown in fig. 2, a feed liquid of a series of alkyl anthracene products containing 2-alkyl anthracene is subjected to first distillation and separated to obtain a distillate containing light component Cj 1-anthracene and a bottom product containing heavy component Cj 2-anthracene; subjecting the distillate containing the light component C1 j-anthracene to second distillation to obtain a distillate containing the light component Cj 3-anthracene and a bottom product containing the target product Ci-anthracene;

wherein, the light component Cj 1-anthracene is an alkyl anthracene product with the total carbon number j1 of an alkyl side chain being an integer which is more than 1 and less than j1 and less than i +1, the heavy component Cj 2-anthracene is an alkyl anthracene product with the total carbon number j2 of the alkyl side chain being an integer which is more than i and less than j2 and less than 41, and the light component Cj 3-anthracene is an alkyl anthracene product with the total carbon number j3 of the alkyl side chain being an integer which is more than 1 and less than j3 and less than i;

wherein, in the target product Ci-anthracene, i represents the total carbon number of an alkyl side chain, i is an integer of 4-7, the substitution position is at 2 position, namely 2-alkyl anthracene, and the total carbon number of the alkyl side chain is 4-7.

The conditions of the first distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-. More preferably, the pressure at the top of the column is 0.1 to 10KPa, the temperature at the bottom of the column is 210-340 ℃, the number of theoretical plates is 30 to 75, and the reflux ratio at the top of the column is 1 to 7. Further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-320 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 3. Under this operating condition, the bottoms were predominantly Cj 2-anthracene product (total alkyl side chain carbon number j2 is an integer of i < j2< 41), and the overheads were Cj 1-anthracene product (total alkyl side chain carbon number j1 is an integer of 1< j1< i + 1).

The conditions of the second distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-330 ℃, the number of theoretical plates is 20-90, and the reflux ratio at the top of the distillation tower is 0.5-8. More preferably, the pressure at the top of the column is from 0.1 to 10KPa, the temperature at the bottom of the column is from 200 ℃ to 310 ℃, the number of theoretical plates is from 30 to 75, and the reflux ratio at the top of the column is from 1 to 7. Further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-300 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 5. Under the operating conditions, the bottom product is Ci-anthracene (2-alkyl anthracene, the total carbon number of alkyl side chain is 4-7), and the overhead product is Cj 3-anthracene (the total carbon number of alkyl side chain j3 is an integer of 1< j3 < i).

For example, as shown in FIG. 2, the alkyl anthracene mixture is a continuous homolog mixture of C2-anthracene to C20-anthracene, while C5-anthracene is the isolated target product. Through the first distillation, light components including C2-anthracene to C5-anthracene are obtained at the top of the tower, and heavy components including C6-anthracene to C20-anthracene are obtained at the bottom of the tower. The mixture of C2-anthracene to C5-anthracene is subjected to second distillation, light components obtained at the top of the tower comprise the mixture of C2-anthracene to C4-anthracene, and a target product of C5-anthracene is obtained at the bottom of the tower.

Or,

mode 2: as shown in fig. 3, the feed liquid of the series alkyl anthracene product containing 2-alkyl anthracene is subjected to third distillation to obtain distillate containing light component Cm 1-anthracene and a bottom product containing heavy component Cm 2-anthracene; carrying out fourth distillation on the bottom product containing the heavy component Cm 2-anthracene to obtain a distillate containing the target product Ci-anthracene and a bottom product containing the heavy component Cm 3-anthracene;

wherein the light component Cm 1-anthracene is an alkyl anthracene product with the total carbon number m1 of an alkyl side chain being an integer of more than 1 and less than m and i, the heavy component Cm 2-anthracene is an alkyl anthracene product with the total carbon number m2 of the alkyl side chain being an integer of more than i and less than m2 and less than 41, and Cm 3-anthracene is an alkyl anthracene product with the total carbon number m3 of the alkyl side chain being an integer of more than i and less than m3 and less than 41;

The conditions of the third distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-. More preferably, the pressure at the top of the column is 0.1 to 10KPa, the temperature at the bottom of the column is 210-340 ℃, the number of theoretical plates is 30 to 75, and the reflux ratio at the top of the column is 1 to 7. Further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-320 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 3. Under this operating condition, the bottoms product was predominantly Cm 2-anthracene product (total alkyl side chain carbon number m2 is an integer from i-1 < m 2< 41), and the overhead product was Cm 1-anthracene product (total alkyl side chain carbon number m1 is an integer from 1< m < i).

The conditions of the fourth distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-330 ℃, the number of theoretical plates is 20-90, and the reflux ratio at the top of the distillation tower is 0.5-8. More preferably, the pressure at the top of the column is from 0.1 to 10KPa, the temperature at the bottom of the column is from 200 ℃ to 310 ℃, the number of theoretical plates is from 30 to 75, and the reflux ratio at the top of the column is from 1 to 7. Further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-300 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 5. Under the operating conditions, the overhead product is Ci-anthracene (2-alkyl anthracene, the total carbon number of the alkyl side chain is 4-7) which is the target product, and the bottom product is Cm 3-anthracene (the total carbon number of the alkyl side chain is m3 which is an integer of i < m3 < 41).

For example, as shown in FIG. 3, the alkyl anthracene mixture is a continuous homolog mixture of C2-anthracene to C20-anthracene, while C5-anthracene is the isolated target product. Through the third distillation, light components including C2-anthracene to C4-anthracene are obtained at the top of the tower, and heavy components including C5-anthracene to C20-anthracene are obtained at the bottom of the tower. And (3) carrying out fourth distillation on a mixture of C5-anthracene to C20-anthracene, obtaining a target product C5-anthracene at the tower top, and obtaining a heavy component from the tower bottom, wherein the heavy component comprises C6-anthracene to C20-anthracene.

According to the present invention, the specific operating conditions of each of the vacuum distillations in the multi-step vacuum distillations can be appropriately selected within the operating temperature and pressure ranges thereof according to the different distillation ranges of the overhead product and the bottom product in each vacuum distillation.

According to the present invention, the multi-step vacuum distillation may employ various vacuum distillation apparatuses known in the art, for example: a sieve tray column or a packed column, more preferably a packed column.

According to the present invention, depending on the process and operating conditions of the reaction of step (1), other substances having a boiling point lower than that of anthracene, such as reaction solvents and other by-products (e.g., alkylating agent remaining after the alkylation reaction), may be entrained or generated, and are referred to as light components. Therefore, the reaction product containing an alkyl anthracene obtained via step (1) also contains a reaction solvent. The method further comprises a step (2-1) of separating the reaction solvent before the separation of anthracene by melt crystallization and the separation of 2-alkyl anthracene by distillation. The method of separating the solvent may be removed using a separation method that is conventional in the art. Preferably, the reaction solvent in the mixed solution containing the alkyl anthracene product is separated by atmospheric distillation from the viewpoint of further improving the separation efficiency and simplifying the operation. According to a specific embodiment of the present invention, the separation method of (2-1) comprises: and (2) distilling the reaction product containing the alkyl anthracene obtained in the step (1) in a distillation tower to obtain a distillate containing the reaction solvent and a tower bottom product containing anthracene and a series of alkyl anthracene products containing 2-alkyl anthracene. In addition, the separated reaction solvent may be recycled or collected for disposal as required for the reaction. In addition, other by-product separation methods can also be in the separation of anthracene alkyl anthracene before separation, can pass through conventional separation methods to remove, such as distillation.

Preferably, in the step (2-1), the distillation conditions include: the bottom temperature of the distillation column is 100-300 ℃, preferably 150-200 ℃, and the pressure at the top of the distillation column is normal pressure.

According to the invention, the intermediate product 2-alkyl anthracene is obtained by separation, and can be used for preparing 2-alkyl anthraquinone through reaction. The method for producing 2-alkylanthraquinone from 2-alkylanthraquinone obtained via step (2) may be any single reaction or a combination of multiple reactions for producing 2-alkylanthraquinone from 2-alkylanthraquinone.

According to the present invention, in the step (3), the 2-alkylanthraquinone is produced from the 2-alkylanthraquinone obtained through the step (2) by subjecting the 2-alkylanthraquinone to an oxidation reaction to produce the 2-alkylanthraquinone. Specifically, in the step (3), the process for producing 2-alkylanthraquinone from 2-alkylanthraquinone obtained via the step (2) comprises: contacting the 2-alkyl anthracene obtained in the step (2) with an oxidizing agent, which is hydrogen peroxide, under oxidizing conditions and in the presence of an oxidizing reaction solvent and a catalyst, wherein the catalyst is one or more selected from the group consisting of an oxide of an alkaline earth metal, a hydroxide of an alkaline earth metal, an oxygen-containing compound of a transition metal, and an oxygen-containing compound of a lanthanide metal.

According to the invention, in the step (3), the oxidant hydrogen peroxide is combined with one or more catalysts selected from the oxides of alkaline earth metals, hydroxides of alkaline earth metals, oxygen-containing compounds of transition metals and oxygen-containing compounds of lanthanide metals, so that the conversion of 2-alkyl anthracene can be effectively realized, the 2-alkyl anthracene catalytic oxidation system is simple and efficient, the separation and recovery difficulty of the catalyst is low, no corrosivity exists, and the equipment investment and the post-treatment cost of the oxidation waste liquid are reduced.

Preferably, in step (3), the catalyst is selected from one or more of group IIA, group IVB, group VB, group VIB, group VIIB, group VIII metals and oxygen-containing compounds of lanthanide metals. For example, the IIA group can Be oxygen-containing compounds of Be, Mg, Ca, Sr and Ba, the IVB group can Be oxygen-containing compounds of Ti and Zr, the VB group can Be oxygen-containing compounds of V, Nb and Ta, the VIB group can Be oxygen-containing compounds of Cr, Mo and W, the VIIB group can Be oxygen-containing compounds of Mn and Re, the VIII group can Be oxygen-containing compounds of Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt, and the lanthanide group can Be oxygen-containing compounds of La, Ce, Pr, Nd, Pm, Sm, Gd, Eu, Dy, Ho, Er, Tm, Yb and Lu. More preferably, the catalyst is selected from one or more of the group consisting of oxygen-containing compounds of Ca, Ba, Ti, Zr, V, Cr, Mo, W, Mn, Ru, Co, Ni, La and Ce. Most preferably, the catalyst is selected from one or more of calcium hydroxide, barium hydroxide, tetravalent titanium oxygenates including metatitanic acid, tetravalent zirconium oxygenates including zirconium dioxide and zirconyl nitrate, pentavalent vanadium oxygenates including sodium metavanadate, hexavalent chromium oxygenates including potassium chromate and chromium trioxide, hexavalent molybdenum oxygenates including sodium molybdate, ammonium molybdate and molybdenum trioxide, hexavalent tungsten oxygenates including sodium tungstate, trivalent manganese and tetravalent manganese oxygenates including manganese dioxide and manganese dioxide, tetravalent ruthenium oxygenates including ruthenium dioxide, trivalent cobalt oxygenates including cobaltous oxide, divalent nickel and trivalent nickel oxygenates including nickel oxide and nickel trioxide, trivalent lanthanum oxygenates including lanthanum nitrate and lanthanum trioxide, tetravalent cerium oxygenates including cerium dioxide.

According to the present invention, in step (3), for convenience of operation, hydrogen peroxide as the oxidizing agent is preferably used in the form of an aqueous hydrogen peroxide solution, the concentration of which is not particularly limited and can be selected by referring to the routine in the art.

According to the present invention, the amount of the oxidizing agent and the catalyst used in step (3) can be selected from a wide range, and preferably, the molar ratio of the oxidizing agent to the catalyst is 0.01:1 to 100:1, more preferably 0.1:1 to 30:1, in order to better achieve the object of the present invention.

According to the present invention, the mode of contacting the 2-alkylanthracene with the oxidizing agent and the catalyst may be various modes capable of achieving the oxidation production of the 2-alkylanthracene to obtain the 2-alkylanthracene. Preferably, for more complete reaction, the contacting is carried out in the following manner: a raw material liquid containing a 2-alkylanthracene, a catalyst and an oxidation reaction solvent is brought into contact with an oxidizing agent to carry out an oxidation reaction.

According to the present invention, in step (3), the conditions and method of the oxidation reaction may be performed in a manner conventional in the art, except for the combination of the above-mentioned hydrogen peroxide oxidizing agent with a specific catalyst.

According to the present invention, in step (3), the oxidizing agent is used in an amount that enables oxidation of 2-alkylanthracene to produce 2-alkylanthracene, preferably in a molar ratio of the oxidizing agent to 2-alkylanthracene of from 0.01:1 to 100:1, more preferably from 1:1 to 50: 1.

According to the present invention, in step (3), the oxidation reaction is generally carried out under conditions including: the reaction temperature can be 10-200 ℃, and preferably 20-120 ℃; the reaction time can be 0.01-48h, preferably 0.5-24 h; the reaction pressure may be from 0 to 1MPa, preferably from 0 to 0.5 MPa.

According to the present invention, in the step (3), the oxidation reaction solvent is an inert organic solvent capable of dissolving the 2-alkylanthracene.

According to a specific embodiment of the present invention, the oxidation reaction solvent is a solvent having a dielectric constant of greater than 2.8 at 20 ℃, preferably, the oxidation reaction solvent is a solvent having a dielectric constant of greater than 2.8 to less than or equal to 50 at 20 ℃; more preferably, the oxidation reaction solvent is one or more of aliphatic alcohol having 1 to 4 carbon atoms, tetrahydrofuran, acetone, N-alkyl substituted amide and N-alkyl pyrrolidone. Wherein the aliphatic alcohol having 1 to 4 carbon atoms may be a monohydric alcohol or a polyhydric alcohol. In the N-alkyl substituted amide, the number of alkyl substituents is 1-2, and each alkyl substituent is independently C₁-C₄Alkyl group of (1). Most preferably, the oxidation reaction solvent is selected from one or more of methanol, t-butanol, acetone, N-dimethylformamide, N-dimethylacetamide, N-dimethylpropionamide, N-methylpyrrolidone, and N-ethylpyrrolidone. The amount of the oxidation reaction solvent is only required to ensure that the 2-alkyl anthracene can be fully dissolved so as to achieve the effect of providing a good reaction medium. Preferably, the 2-alkylanthracene is present in an amount of 0.1 to 80 wt%, preferably 5 to 50 wt%, based on the total weight of the 2-alkylanthracene and the oxidation reaction solvent.

According to another embodiment of the present invention, the oxidation reaction solvent is a combination of a solvent A having a dielectric constant of 1 to 10 at 20 ℃ and a solvent B having a dielectric constant of more than 10 to 50 or less at 20 ℃. The inventors of the present invention have found that, in the oxidation reaction in step (3), a combination solvent of a solvent a having a dielectric constant of 1 to 10 at 20 ℃ and a solvent B having a dielectric constant of more than 10 to 50 or less at 20 ℃ is used as the oxidation reaction solvent, and that the solvent properties can be specifically controlled, and the dissolution of 2-alkylanthracene and the promotion of the oxidation reaction can be enhanced by solvation, and the conversion of 2-alkylanthracene can be improved.

According to the invention, in step (3), in order to better achieve the invention purpose of enhancing the oxidation reaction by regulating the solvent property, the volume ratio of the solvent A to the solvent B is 0.01-100, and more preferably 0.05-10.

According to the second embodiment, the oxidation reaction solvent is used in the step (3) in an amount sufficient to ensure that the 2-alkylanthracene is sufficiently soluble to provide a good reaction medium. Preferably, the 2-alkylanthracene is present in an amount of 0.1 to 80 wt%, preferably 5 to 50 wt%, based on the total weight of the 2-alkylanthracene and the oxidation reaction solvent.

According to the present invention, in the step (3), the preparation of 2-alkylanthraquinone from 2-alkylanthracene requires the use of a catalyst, and the catalyst after the reaction can be separated by a separation method which is conventional in the art according to the nature of the catalyst. The 2-alkylanthraquinone in the product is the target product, if other substances including the residual 2-alkylanthraquinone, solvent and generated by-products exist, the 2-alkylanthraquinone can be removed or purified respectively by adopting a conventional separation method or a combined separation method according to the difference of the properties of the substances.

The present invention will be described in detail below by way of examples.

The material composition data are obtained by chromatographic analysis.

The chromatographic analysis method comprises the following steps: agilent 7890A, column DB-1(50 m.times.0.25 mm. times.0.25 μm). Sample inlet temperature: 330 ℃, sample introduction: 0.2 mu L, the split ratio of 20:1, nitrogen as carrier gas, the flow rate of constant flow mode of 0.7mL/min, temperature programming: keeping the temperature at 110 ℃ for 10min, then increasing the temperature to 320 ℃ at the speed of 5 ℃/min, and keeping the temperature for 18 min. FID detector: temperature 350 ℃, hydrogen flow: 35mL/min, air flow: 350mL/min, tail gas blowing is nitrogen, and the flow is as follows: 25 mL/min.

Defining the conversion rate of anthracene as X in the alkylation reaction of step (1)₁The substance selectivity calculated on a molar basis is S (mol%). The mass fraction was expressed as a percentage of the chromatographic peak area of each substance, and the fraction W (% by mol) based on the molar amount of each substance was calculated in combination with the molar mass.

AN is used for representing anthracene, Ci-AN represents 2-alkyl anthracene, and Cj-AN represents other alkyl anthracene.

The conversion of anthracene is shown in formula 1:

the 2-alkyl anthracene selectivity is shown in formula 2:

(II) in the separation process of the step (2), the purity B of a certain substance is the mass fraction of the substance, and the purity of the separated anthracene is B₁The purity of the separated 2-alkyl anthracene is B₂Calculated based on chromatographic data. The anthracene and alkyl anthracene mixture to be separated was chromatographed. Preparing external standard mark by adopting high-purity 2-alkyl anthracene and mesityleneAnalyzing curve, quantitatively calculating the content of 2-alkyl anthracene in the mixture of anthracene and 2-alkyl anthracene, and recording as W₀And g. The amount of 2-alkylanthracene actually isolated according to the process proposed by the invention is denoted W₁And g. The yield Y of the separation process is calculated as shown in formula 3 below.

(III) in the oxidation reaction of the step (3), the conversion rate of Ci-AN is defined as X₂The substance selectivity calculated on a molar basis is S (mol%). The mass fraction was expressed as a percentage of the chromatographic peak area of each substance, and the fraction W (% by mol) based on the molar amount of each substance was calculated in combination with the molar mass.

Ci-AN is adopted to represent 2-alkyl anthracene, Ci-AO is adopted to represent 2-alkyl anthraquinone, and Ci-X is adopted to represent other byproducts.

The 2-alkyl anthracene conversion is shown as formula 4:

the 2-alkylanthraquinone selectivity is shown in formula 5:

the following examples 1-17 are provided to illustrate the preparation of the 2-alkylanthraquinones provided by the present invention.

Example 1

And (I) alkylation reaction.

The 2-pentylanthracene, the mesitylene and the N, N-dimethylformamide are prepared by alkylating anthracene and isoamylene and are used as a combined solvent, the catalyst is a spherical catalyst containing an active Y-type molecular sieve, alumina is used as a binder, the total weight of the catalyst is used as a reference, the content of the active Y-type molecular sieve is 82 wt%, the content of the binder is 18 wt%, and the average particle size of catalyst particles is 100 mu m. 460g of anthracene, 640ml of mesitylene, 160ml of N, N-dimethylformamide and 205g of catalyst were added to a 2L stirred tank at room temperature. After sealing, the temperature is raised to 165 ℃ at the rotation speed of 1000 rpm, and the pressure is 0.3 MPa. 151g of isoamylene was added to the kettle by means of a plunger pump at a feed rate of 6.6 g/min. When the feeding of the isoamylene is finished, the reaction is continued for 270min while the reaction conditions are kept unchanged, and then the reaction is stopped. Reacting for 10 batches under the same condition, separating the catalyst, and uniformly collecting the alkylation reaction product as the raw material for separating the alkyl anthracene.

(II) separating.

The alkylation reaction product is sent to a normal pressure distillation system, the temperature is raised to 165 ℃ under normal pressure, and the remaining light components with boiling points lower than that of anthracene, such as isoamylene, mesitylene, N-dimethylformamide and the like, can be separated out in sequence. The rest is a solid mixture of anthracene-alkyl anthracene, the mixture is heated to 220 ℃ and is in a molten state and sent into an intermittent melting crystallization system, the melting crystallizer is a tubular crystallizer, and cooling medium is introduced to start temperature reduction and crystallization. The cooling rate is 0.5 ℃/h, the cooling crystallization temperature is 200 ℃, the amount of the seed crystal anthracene added is 0.5 weight percent of the mass of the molten mixture, and the crystal growth time is controlled to be 2 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating up and sweating the crystals in the crystallizer, wherein the heating up rate is 0.2 ℃/h, the sweating finishing temperature is 205 ℃, the sweating amount is 25 weight percent of the mass of the crystals, and the sweating liquid circulates and is contacted with the materials entering the melt crystallizer to be crystallized together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1KPa, the temperature at the bottom of the tower is 259 ℃, the number of theoretical plates is 65, and the reflux ratio at the top of the tower is 1.5. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 248 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 3. And collecting a product 2-pentylanthracene at the bottom of the tower.

(III) oxidation reaction.

The 2-amyl anthracene is oxidized in a liquid phase to prepare the 2-amyl anthraquinone. Into an 8L glass kettle were added 3000ml of methanol, 150g of 2-pentylanthracene, and 156g of potassium chromate. The reaction is carried out at the normal pressure of 65 ℃, 1368g of hydrogen peroxide (the content of hydrogen peroxide is 30 weight percent) is added into the kettle by a peristaltic pump, and the feeding rate is 2 g/min. After the feeding is finished, the reaction is continued for 2 hours while the conditions are maintained. After the reaction is finished, transferring the materials in the kettle into a 20L glass stirring kettle, adding 2000ml of mesitylene and 3000ml of deionized water for extraction and washing, standing, separating out the mesitylene phase containing 2-amylanthraquinone on the upper layer, and distilling to obtain the final product 2-amylanthraquinone. The lower aqueous phase is distilled, and after water is separated, the catalyst can be obtained again.

Conversion rate X of anthracene in the step (I)₁Selectivity of 2-pentylanthracene_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-pentylanthracene purity B₂The total yield of the 2-pentylanthracene separation process is Y, and the conversion rate of the 2-pentylanthracene in the step (III) is X₂And 2-amylanthraquinone-selective S_Ci-AOAs shown in table 1.

Comparative example 1

2-Alkylanthraquinone was prepared according to the method of example 1, except that mesitylene alone was used as the reaction solvent in step (one); after distilling off light components with boiling points lower than that of anthracene in the step (II), anthracene is separated by a method of direct reduced pressure distillation instead of a method of melt crystallization. The distillation tower for separating anthracene is marked as anthracene-separating reduced pressure distillation system, the pressure at the top of the tower is 8KPa, the distillation temperature is 275 ℃, the number of theoretical plates is 20, and the reflux ratio at the top of the tower is 0.7. The bottom product was subjected to the first vacuum distillation and the second vacuum distillation under the same conditions as in example 1.

In step (III), 3000ml of methanol, 150g of 2-pentylanthracene, and 307g of 36 wt% hydrochloric acid were charged in a 5L glass vessel. The reaction was carried out at atmospheric pressure and 65 ℃ with a peristaltic pump feeding 342g of hydrogen peroxide (30 wt% hydrogen peroxide) into the kettle at a feed rate of 2 g/min. After the feeding is finished, the reaction is continued for 2 hours while the conditions are maintained. After the reaction is finished, transferring the materials in the kettle into a 20L glass stirring kettle, adding 2000ml of mesitylene and 3000ml of deionized water for extraction and washing, standing, separating out the mesitylene phase containing 2-amylanthraquinone on the upper layer, and distilling to obtain the final product 2-amylanthraquinone.

Example 2

2-Alkylanthraquinone was prepared according to the method of example 1, except that in the second step, the temperature lowering rate was 5.0 ℃/h, the crystallization temperature was 190 ℃, the amount of anthracene added as a seed crystal was 4% by weight based on the mass of the molten mixture, and the crystal growth time was controlled to 4 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating up and sweating the crystals in the crystallizer, wherein the heating up rate is 4 ℃/h, the sweating finishing temperature is 195 ℃, the sweating amount is 10 weight percent of the mass of the crystals, and the sweating is circulated and contacted with the materials entering the melt crystallizer, and then the crystallization operation is carried out together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1KPa, the temperature at the bottom of the tower is 259 ℃, the number of theoretical plates is 65, and the reflux ratio at the top of the tower is 1.5. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 248 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 3. And collecting a product 2-pentylanthracene at the bottom of the tower.

Example 3

2-Alkylanthraquinone was prepared according to the method of example 1, except that in the step (II), the uncrystallized alkylanthracene mixture was fed to a vacuum distillation system to conduct a third vacuum distillation at a head pressure of 1KPa, a bottom temperature of 252 ℃ C., a theoretical plate number of 65 and a head reflux ratio of 1.5. And carrying out fourth reduced pressure distillation on the distillate at the tower bottom, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 264 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 3. And collecting a product 2-pentylanthracene at the top of the tower.

Conversion of Anthracene in step (I)Conversion rate X₁Selectivity of 2-pentylanthracene_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-pentylanthracene purity B₂The total yield of the 2-pentylanthracene separation process is Y, and the conversion rate of the 2-pentylanthracene in the step (III) is X₂And 2-amylanthraquinone-selective S_Ci-AOAs shown in table 1.

Example 4

2-Alkylanthraquinone was prepared according to the method of example 1, except that in the second step, the temperature lowering rate was 2 ℃/h, the crystallization temperature was 192 ℃, the amount of anthracene added as a seed crystal was 2% by weight of the mass of the molten mixture, and the crystal growth time was controlled to 3 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating and sweating the crystals in the crystallizer, wherein the heating rate is 2.0 ℃/h, the sweating finishing temperature is 197 ℃, the sweating amount is 15 weight percent of the mass of the crystals, and the sweating is circulated and contacted with the materials entering the melt crystallizer to be crystallized together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1KPa, the temperature at the bottom of the tower is 259 ℃, the number of theoretical plates is 40, and the reflux ratio at the top of the tower is 1.5. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 248 ℃, the number of theoretical plates is 40, and the reflux ratio at the tower top is 3. And collecting a product 2-pentylanthracene at the bottom of the tower.

Example 5

2-Alkylanthraquinone was prepared according to the method of example 1, except that in the second step, the temperature lowering rate was 1 ℃/h, the crystallization temperature was 197 ℃, the amount of anthracene added as a seed crystal was 1% by weight of the mass of the molten mixture, and the crystal growth time was controlled to 1.5 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating and sweating the crystals in the crystallizer, wherein the heating rate is 0.6 ℃/h, the sweating finishing temperature is 202 ℃, the sweating amount is 20 weight percent of the mass of the crystals, and the sweating is circulated and contacted with the materials entering the melt crystallizer to be crystallized together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 0.8KPa, the temperature at the bottom of the tower is 239 ℃, the number of theoretical plates is 75, and the reflux ratio at the top of the tower is 2. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1.2KPa, the temperature at the tower bottom is 274 ℃, the number of theoretical plates is 75, and the reflux ratio at the tower top is 4. And collecting a product 2-pentylanthracene at the bottom of the tower.

Example 6

2-Alkylanthraquinone was prepared according to the method of example 1, except that in the second step, the temperature lowering rate was 1.5 ℃/h, the crystallization temperature was 195 ℃, the amount of anthracene added as a seed crystal was 1.5% by weight based on the mass of the molten mixture, and the crystal growth time was controlled to 2.5 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating up and sweating the crystals in the crystallizer, wherein the heating up rate is 1 ℃/h, the sweating finishing temperature is 199 ℃, the sweating amount is 30 weight percent of the mass of the crystals, and the sweating is circulated and contacted with the materials entering the melt crystallizer, and then the crystallization operation is carried out together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1.2KPa, the temperature at the bottom of the tower is 279 ℃, the number of theoretical plates is 65, and the reflux ratio at the top of the tower is 1. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 0.8KPa, the temperature at the tower bottom is 236 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 1. And collecting a product 2-pentylanthracene at the bottom of the tower.

Example 7

When 2-butylanthraquinone was used as a target product, the other materials and reaction conditions were the same as in example 1 except that in the step (I), 2-methyl-2-butene was changed to isobutylene in an amount of 121g, and the alkylation reaction was carried out in the same manner as in example 1. In the second step, the cooling rate is 0.5 ℃/h, the cooling crystallization temperature is 200 ℃, the amount of the seed crystal anthracene added is 0.5 weight percent of the mass of the molten mixture, and the crystal growth time is controlled to be 2 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating up and sweating the crystals in the crystallizer, wherein the heating up rate is 0.2 ℃/h, the sweating finishing temperature is 205 ℃, the sweating amount is 25 weight percent of the mass of the crystals, and the sweating liquid circulates and is contacted with the materials entering the melt crystallizer to be crystallized together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1KPa, the temperature at the bottom of the tower is 250 ℃, the number of theoretical plates is 65, and the reflux ratio at the top of the tower is 1.5. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 238 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 3. Collecting the product 2-butylanthracene at the bottom of the tower. In the third step, the oxidation reaction solvent was a mixture of 300ml of 1,3, 5-trimethylbenzene and 2700ml of N, N-dimethylformamide. The catalyst was zirconium dioxide, 79 g. 1453g of hydrogen peroxide and the reaction temperature is 95 ℃.

Conversion rate X of anthracene in the step (I)₁Selectivity of 2-butylanthracene S_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-butylanthracene purity B₂The total yield of the 2-butylanthracene separation process is Y, and the conversion rate of the 2-butylanthracene in the step (III) is X₂And 2-butylanthraquinone Selective S_Ci-AOAs shown in table 1.

Example 8

When 2-hexylanthracene was used as a target product, the other materials and reaction conditions were the same as in example 1, except that in the step (I), 2-methyl-2-butene was changed to 2-methyl-2-pentene in an amount of 181g, and the alkylation was carried out in the same manner as in example 1. In the second step, the cooling rate is 0.5 ℃/h, the cooling crystallization temperature is 200 ℃, the amount of the seed crystal anthracene added is 0.5 weight percent of the mass of the molten mixture, and the crystal growth time is controlled to be 2 h. After the crystallization process is finished, discharging the feed liquid which is not crystallized and sending the feed liquid into a reduced pressure distillation system. Slowly heating up and sweating the crystals in the crystallizer, wherein the heating up rate is 0.2 ℃/h, the sweating finishing temperature is 205 ℃, the sweating amount is 25 weight percent of the mass of the crystals, and the sweating liquid circulates and is contacted with the materials entering the melt crystallizer to be crystallized together. Sending the uncrystallized alkyl anthracene mixture into a reduced pressure distillation system for first reduced pressure distillation, wherein the pressure at the top of the tower is 1KPa, the temperature at the bottom of the tower is 273 ℃, the number of theoretical plates is 65, and the reflux ratio at the top of the tower is 1.5. And carrying out second reduced pressure distillation on the distillate at the tower top, wherein the pressure at the tower top is 1KPa, the temperature at the tower bottom is 261 ℃, the number of theoretical plates is 70, and the reflux ratio at the tower top is 3. Collecting the bottom product 2-hexyl anthracene. In the third step, the oxidation reaction solvent was a mixture of 300ml of 1,3, 5-trimethylbenzene and 2700ml of N, N-dimethylformamide. The catalyst was metatitanic acid, 224 g. 1298g of hydrogen peroxide and 95 ℃ of reaction temperature.

Conversion rate X of anthracene in the step (I)₁S selectivity to 2-hexyl anthracene_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-hexyl anthracene purity B₂The total yield of the separation process of the 2-hexyl anthracene is Y, and the conversion rate of the 2-hexyl anthracene in the step (III) is X₂And 2-hexylanthraquinone-selective S_Ci-AOAs shown in table 2.

Example 9

Step (one) was the same as in example 1 except that the combined solvent was changed to 640ml of 2,3,5, 6-tetramethylbenzene and 160ml of N, N-dimethylformamide.

Step (ii) is the same as in example 1.

Step (III) was the same as in example 1, except that the amount of 2-pentylanthracene used was 266g, and the oxidation reaction solvent was a mixture of 2700ml of 1,3, 5-trimethylbenzene and 300ml of N, N-dimethylformamide. The catalyst was lanthanum nitrate hexahydrate, 116 g. 607.5g of hydrogen peroxide and 120 ℃ of reaction temperature.

Conversion rate X of anthracene in the step (I)₁Selectivity of 2-pentylanthracene_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-pentylanthracene purity B₂The total yield of the 2-pentylanthracene separation process is Y, and the conversion rate of the 2-pentylanthracene in the step (III) is X₂And 2-amylanthraquinone-selective S_Ci-AOAs shown in table 2.

Example 10

Step (one) was the same as in example 1 except that the combined solvent was changed to 640ml of 1,3, 5-trimethylbenzene and 160ml of N, N-dimethylacetamide.

Step (ii) is the same as in example 1.

Step (III) was the same as in example 1, except that the amount of 2-pentylanthracene used was 600g, and the oxidation reaction solvent was a mixture of 1500ml of 1,3, 5-trimethylbenzene and 1500ml of N, N-dimethylformamide. The catalyst was lanthanum nitrate hexahydrate, 262 g. 1370g of hydrogen peroxide and 120 ℃ of reaction temperature.

Example 11

Step (one) was the same as in example 1 except that the combined solvent was changed to 720ml of 1,3, 5-trimethylbenzene and 80ml of N, N-dimethylformamide.

Step (ii) is the same as in example 1.

Step (III) was the same as in example 1, except that the oxidation reaction solvent was a mixture of 300ml of 2,3,5, 6-tetramethylbenzene and 2700ml of N, N-dimethylacetamide. The catalyst was zirconium dioxide, 74 g. 1368g of hydrogen peroxide and 95 ℃ of reaction temperature.

Conversion rate X of anthracene in the step (I)₁Selection of 2-pentylanthraceneSex S_Ci-ANAnd (II) separating the obtained anthracene in the step (II) to obtain the anthracene with the purity B₁Intermediate 2-pentylanthracene purity B₂The total yield of the 2-pentylanthracene separation process is Y, and the conversion rate of the 2-pentylanthracene in the step (III) is X₂And 2-amylanthraquinone-selective S_Ci-AOAs shown in table 2.

Example 12

Step (one) was the same as in example 1 except that the combined solvent was changed to 80ml of mesitylene and 720ml of N, N-dimethylacetamide.

Step (ii) is the same as in example 1.

Step (three) was the same as in example 1, except that the oxidation reaction solvent was 3000ml of 1,3, 5-mesitylene. The catalyst was sodium molybdate, 124 g. 1368g of hydrogen peroxide and 95 ℃ of reaction temperature.

Example 13

And (I) alkylation reaction.

The 2-pentylanthracene, the mesitylene and the N, N-dimethylformamide are prepared by alkylating anthracene and isoamylene and are used as a combined solvent, the catalyst is a spherical catalyst containing an active Y-type molecular sieve, alumina is used as a binder, the total weight of the catalyst is used as a reference, the content of the active Y-type molecular sieve is 82 wt%, the content of the binder is 18 wt%, and the average particle size of catalyst particles is 100 mu m. 76g of anthracene, 640ml of mesitylene, 160ml of N, N-dimethylformamide and 333.6g of a catalyst were added to a 2L stirred tank at room temperature. After sealing, the temperature is raised to 110 ℃ at the rotating speed of 1000 rpm, and the pressure is 0.15 MPa. 60g of isoamylene was added to the kettle by means of a plunger pump at a feed rate of 3 g/min. When the feeding of the isoamylene is finished, the reaction is continued for 270min while the reaction conditions are kept unchanged, and then the reaction is stopped. Reacting for 10 batches under the same condition, separating the catalyst, and uniformly collecting the alkylation reaction product as the raw material for separating the alkyl anthracene.

The step (ii) and the step (iii) are the same as in example 1.

Example 14

And (I) alkylation reaction.

The 2-pentylanthracene, the mesitylene and the N, N-dimethylformamide are prepared by alkylating anthracene and isoamylene and are used as a combined solvent, the catalyst is a spherical catalyst containing an active Y-type molecular sieve, alumina is used as a binder, the total weight of the catalyst is used as a reference, the content of the active Y-type molecular sieve is 82 wt%, the content of the binder is 18 wt%, and the average particle size of catalyst particles is 100 mu m. To a 2L stirred tank was added 229g of anthracene, 640ml of mesitylene, 160ml of N, N-dimethylformamide, and 4.68g of a catalyst at room temperature. After sealing, the temperature is raised to 130 ℃ at the rotation speed of 1000 rpm, and the pressure is 0.15 MPa. 18g of isoamylene was added to the kettle by means of a plunger pump at a feed rate of 2 g/min. When the feeding of the isoamylene is finished, the reaction is continued for 270min while the reaction conditions are kept unchanged, and then the reaction is stopped. Reacting for 10 batches under the same condition, separating the catalyst, and uniformly collecting the alkylation reaction product as the raw material for separating the alkyl anthracene.

The step (ii) and the step (iii) are the same as in example 1.

Example 15

Both the step (one) and the step (two) were the same as in example 1. Except that, in the step (III), 2-pentylanthracene was used in an amount of 150g, and the oxidation reaction solvent was 3000ml of N, N-dimethylformamide. The catalyst was zirconium dioxide, 74 g. 1368g of hydrogen peroxide and 95 ℃ of reaction temperature.

Example 16

Both the step (one) and the step (two) were the same as in example 1. Except that, in the step (III), 2-pentylanthracene was used in an amount of 150g, and the oxidation reaction solvent was 3000ml of N, N-dimethylformamide. The catalyst was sodium molybdate, 124 g. 1368g of hydrogen peroxide and 95 ℃ of reaction temperature.

Example 17

Both the step (one) and the step (two) were the same as in example 1. Except that, in the step (III), 2-pentylanthracene was used in an amount of 150g, and the oxidation reaction solvent was 3000ml of N, N-dimethylformamide. The catalyst was iron oxide, 97 g. 1368g of hydrogen peroxide and 95 ℃ of reaction temperature.

The results in table 1 show that, in the method for preparing 2-alkylanthraquinone by catalytic oxidation of 2-alkylanthraquinone obtained by alkylation of anthracene, the alkylation reaction can be strengthened and the conversion of anthracene can be improved by using the combined solvent as the reaction medium in the alkylation reaction process, which is more beneficial to the generation of the target product. Through a melt crystallization-distillation coupling separation technology, the purity of the crystal anthracene obtained by separation, the purity of the intermediate product 2-pentylanthracene (2-butylanthracene, 2-hexylanthracene) and the total yield of the separation process of the 2-pentylanthracene (2-butylanthracene, 2-hexylanthracene) are obviously improved compared with the prior art, and the total yield of the finally obtained 2-alkylanthraquinone is also improved.

Compared with the prior art, the 2-alkyl anthracene oxidation technology provided by the invention has the advantages of low efficiency, simple system, no corrosivity, no generation of chlorine-containing wastewater, easy recovery of the catalyst, and simple and clean process. The developed combined solvent system can enhance the conversion of the 2-alkyl anthracene and improve the selectivity of the 2-alkyl anthraquinone by adjusting the solvent property.

Therefore, the method provided by the invention opens up a new direction for the green preparation of the 2-alkylanthraquinone.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method for preparing 2-alkyl anthraquinone by catalytic oxidation of 2-alkyl anthracene obtained by alkylation of anthracene is characterized by comprising the following steps:

2. The production method according to claim 1, wherein, in the step (1),

the solvent A is C₆Above, preferably C₆-C₁₂One or more of paraffins, naphthenes and aromatics; wherein the aromatic hydrocarbon is substituted or unsubstituted, preferably one or more of monobasic or polybasic substituted substances of benzene, more preferably one or more of polybasic substituted substances of benzene, and the substituent is C₁-C₄One or more of alkyl and halogen elements of (a);

more preferably, the solvent A is one or more of polyalkyl substituents of benzene, and most preferably, the solvent A is selected from one or more of 1,3, 5-trimethylbenzene, 1,2,3, 5-tetramethylbenzene, 1,3,4, 5-tetramethylbenzene, 1,3,5, 6-tetramethylbenzene and 2,3,5, 6-tetramethylbenzene;

the solvent B is N-alkyl substituted amide, wherein the number of alkyl substituents is 1-2, and each alkyl substituent is independently C₁-C₄Alkyl groups of (a); more preferably, the solvent B is selected from one or more of N, N-dimethylformamide, N-dimethylacetamide and N, N-dimethylpropionamide, and most preferably, the solvent B is N, N-dimethylformamide.

3. The production method according to claim 1 or 2, wherein the volume ratio of the solvent a to the solvent B in the step (1) is 0.01 to 100, preferably 0.1 to 10.

4. The production method according to any one of claims 1 to 3, wherein in the step (1), the content of anthracene is 5 to 60% by weight, preferably 8 to 50% by weight, based on the total weight of anthracene and the alkylation reaction solvent.

5. The preparation method according to claim 1, wherein in step (1), the alkylating reagent is one or more of olefins, alcohols, halogenated hydrocarbons and ethers having 2 to 8 carbon atoms, preferably one or more of olefins, alcohols, halogenated hydrocarbons and ethers having 4 to 6 carbon atoms, and more preferably mono-olefins having 4 to 6 carbon atoms.

6. The production process according to claim 1 or 5, wherein in the step (1), the molar ratio of anthracene to the alkylating agent is from 0.2:1 to 20:1, preferably from 0.5:1 to 5: 1.

7. The production method according to claim 1, wherein in the step (1), the contacting is carried out by: the raw material liquid containing anthracene, catalyst and alkylation reaction solvent is contacted with alkylation reagent to make alkylation reaction.

8. The production method according to claim 7, wherein in the step (1), the catalyst is a solid acid catalyst containing an active molecular sieve and a binder, the active molecular sieve is contained in an amount of 30 to 95 mass% and the binder is contained in an amount of 5 to 70 mass%, based on the total weight of the solid acid catalyst, and the active molecular sieve is selected from one or more of an X-type molecular sieve, a Y-type molecular sieve, a beta molecular sieve, a ZSM-5 molecular sieve, a SAPO molecular sieve and a mesoporous molecular sieve, preferably a Y-type molecular sieve; the binder is an inorganic binder, and the inorganic binder is a heat-resistant inorganic oxide and/or silicate, preferably alumina;

the content of the catalyst is 0.01 to 50% by weight, preferably 0.5 to 30% by weight, based on the total weight of the raw material liquid containing anthracene, the catalyst and the alkylation reaction solvent.

9. The preparation method according to claim 1, wherein in the step (1), the alkylation reaction conditions include: the reaction temperature is 100-250 ℃, preferably 120-200 ℃; the reaction pressure is 0-1MPa, preferably 0.05-0.5 MPa; the reaction time is 0.01-48h, preferably 0.5-24 h.

10. The production method according to any one of claims 1 to 9, wherein the reaction product containing alkyl anthracene obtained through step (1) contains anthracene and a series of alkyl anthracene products containing 2-alkyl anthracene;

the step (2) comprises the following steps:

(2-3) separating 2-alkyl anthracene from the series of alkyl anthracene products containing 2-alkyl anthracene by one or more distillation steps.

11. The preparation method according to claim 10, wherein, in the step (2-2), the melting temperature is 200-.

12. The preparation method according to claim 10 or 11, wherein in the step (2-2), the cooling crystallization temperature is 180-210 ℃, the cooling rate of the cooling crystallization is 0.1-10 ℃/h, and the cooling crystallization time is 1-5 h; preferably, the cooling crystallization temperature is 190-.

13. The production method according to claim 12, wherein in the step (2-2), in the cooling crystallization, a step of adding seed anthracene in an amount of 0.1 to 10% by weight, preferably 0.2 to 5% by weight, based on the mass of the molten mixture is further included.

14. The production method according to claim 10 or 11, wherein in the step (2-2), the temperature increase rate at which the anthracene crystal is subjected to sweating is 0.1 to 8 ℃/h, preferably 0.2 to 4 ℃/h; raising the temperature to a temperature lower than the melting temperature of the anthracene crystal to stop sweating, preferably raising the temperature to a temperature lower than or equal to 210 ℃ to stop sweating, more preferably raising the temperature to a temperature 5 to 15 ℃ higher than the cooling crystallization temperature and stopping sweating below 210 ℃; further preferably, the sweating completion temperature is 190-210 ℃, and most preferably 195-205 ℃.

15. The production method according to claim 14, wherein the amount of perspiration is 5 to 40% by weight, preferably 10 to 30% by weight, based on the mass of the anthracene crystal.

16. The method of claim 14, further comprising recycling sweat back to the melt crystallization step for melt crystallization with the reaction product containing alkyl anthracene.

17. The production method according to claim 10, wherein, in the step (2-3), when the series of alkyl anthracene products containing 2-alkyl anthracene is a mixture of two substances, or a mixture of three or more substances, and the boiling point of 2-alkyl anthracene is the lowest or the highest; then a one-step distillation is performed to separate the 2-alkyl anthracene.

18. The production method according to claim 10, wherein, in the step (2-3), when the series of alkyl anthracene products containing 2-alkyl anthracene is a mixture of three or more substances, and the boiling point of 2-alkyl anthracene is between the substance with the highest boiling point and the substance with the lowest boiling point in the mixture; then a multi-stage distillation is performed, the multi-stage distillation method comprising:

mode 1:

carrying out first distillation on feed liquid of a series of alkyl anthracene products containing 2-alkyl anthracene, and separating to obtain distillate containing a light component Cj 1-anthracene and a bottom product containing a heavy component Cj 2-anthracene; subjecting the distillate containing the light component Cj 1-anthracene to second distillation to obtain a distillate containing the light component Cj 3-anthracene and a bottom product containing the target product Ci-anthracene;

or,

mode 2:

carrying out third distillation on feed liquid of a series of alkyl anthracene products containing 2-alkyl anthracene to obtain distillate containing a light component Cm 1-anthracene and a bottom product containing a heavy component Cm 2-anthracene; carrying out fourth distillation on the bottom product containing the heavy component Cm 2-anthracene to obtain a distillate containing the target product Ci-anthracene and a bottom product containing the heavy component Cm 3-anthracene;

wherein the light component Cm 1-anthracene is an alkyl anthracene product with the total carbon number of the alkyl side chain m1 being an integer of 1< m 1< i, the heavy component Cm 2-anthracene is an alkyl anthracene product with the total carbon number of the alkyl side chain m2 being an integer of i-1 < m 2< 41, and Cm 3-anthracene is an alkyl anthracene product with the total carbon number of the alkyl side chain m3 being an integer of i < m3 < 41;

wherein, in the target product Ci-anthracene, i represents the total carbon number of an alkyl side chain, and i is an integer of 4-7.

19. The production method according to claim 18, wherein in the multi-step reduced pressure distillation step, mode 1, the conditions of the first reduced pressure distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-; more preferably, the pressure at the top of the tower is 0.1-10KPa, the temperature at the bottom of the tower is 210-340 ℃, the number of theoretical plates is 30-75, and the reflux ratio at the top of the tower is 1-7; further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-320 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 3.

20. The production method according to claim 18 or 19, wherein in the multi-step reduced pressure distillation step, mode 1, the conditions of the second reduced pressure distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-330 ℃, the number of theoretical plates is 20-90, and the reflux ratio at the top of the distillation tower is 0.5-8; more preferably, the pressure at the top of the tower is 0.1-10KPa, the temperature at the bottom of the tower is 200-310 ℃, the number of theoretical plates is 30-75, and the reflux ratio at the top of the tower is 1-7; further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-300 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 5.

21. The production method according to claim 18, wherein in the multi-step reduced pressure distillation step, mode 2, the conditions of the third reduced pressure distillation include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-; more preferably, the pressure at the top of the tower is 0.1-10KPa, the temperature at the bottom of the tower is 210-340 ℃, the number of theoretical plates is 30-75, and the reflux ratio at the top of the tower is 1-7; further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-320 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 3.

22. The production method according to claim 18 or 21, wherein in the multi-step reduced pressure distillation step, mode 2, the fourth reduced pressure distillation conditions include: the pressure at the top of the distillation tower is 0.01-20KPa, the temperature at the bottom of the distillation tower is 180-330 ℃, the number of theoretical plates is 20-90, and the reflux ratio at the top of the distillation tower is 0.5-8; more preferably, the pressure at the top of the tower is 0.1-10KPa, the temperature at the bottom of the tower is 200-310 ℃, the number of theoretical plates is 30-75, and the reflux ratio at the top of the tower is 1-7; further preferably, the pressure at the top of the distillation column is 0.5 to 2KPa, the temperature at the bottom of the distillation column is 220-300 ℃, the number of theoretical plates is 40 to 75, and the reflux ratio at the top of the distillation column is 1 to 5.

23. The production method according to any one of claims 10 to 22, wherein the reaction product containing an alkyl anthracene obtained through step (1) further contains an alkylation reaction solvent;

the step (2) further comprises: a step (2-1) of separating the alkylation reaction solvent prior to the separation of anthracene by melt crystallization and the separation of 2-alkyl anthracene by distillation;

(2-1) the separation method comprising: and (2) distilling the reaction product containing the alkyl anthracene obtained in the step (1) in a distillation tower to obtain a distillate containing an alkylation reaction solvent and a tower bottom product containing anthracene and a series of alkyl anthracene products containing 2-alkyl anthracene.

24. The production method according to claim 23, wherein in the step (2-1), the conditions of distillation include: the bottom temperature of the distillation column is 100-300 ℃, preferably 150-200 ℃, and the pressure at the top of the distillation column is normal pressure.

25. The process according to claim 1, wherein in the step (3), the catalyst is one or more selected from the group consisting of oxygen-containing compounds of group IIA, group IVB, group VB, group VIB, group VIIB, group VIII metals and lanthanoid metals.

26. The production method according to claim 25, wherein the catalyst is selected from one or more of oxygen-containing compounds of Ca, Ba, Ti, Zr, V, Cr, Mo, W, Mn, Ru, Co, Ni, La, and Ce.

27. The method of claim 26, wherein the catalyst is selected from one or more of calcium hydroxide, barium hydroxide, metatitanic acid, zirconium dioxide, zirconyl nitrate, sodium metavanadate, potassium chromate, chromium oxide, sodium molybdate, ammonium molybdate, molybdenum trioxide, sodium tungstate, manganese oxide, manganese dioxide, ruthenium dioxide, cobaltous oxide, nickel trioxide, lanthanum nitrate, lanthanum trioxide, and cerium dioxide.

28. The method of claim 1, wherein the contacting is by: a raw material liquid containing a 2-alkylanthracene, a catalyst and an oxidation reaction solvent is brought into contact with an oxidizing agent to carry out an oxidation reaction.

29. The production method according to any one of claims 1 and 25 to 28, wherein the molar ratio of the oxidizing agent to the catalyst is 0.01:1 to 100:1, preferably 0.1:1 to 30: 1.

30. The production method according to any one of claims 1 and 25 to 28, wherein the conditions of the oxidation reaction include: the reaction temperature is 10-200 ℃, and preferably 20-120 ℃; the reaction pressure is 0-1MPa, preferably 0-0.5 MPa; the reaction time is 0.01-48h, preferably 0.5-24 h.

31. The production method according to any one of claims 1, 25 to 28, wherein the hydrogen peroxide is used in the form of an aqueous hydrogen peroxide solution; the molar ratio of oxidant to 2-alkyl anthracene is 0.01:1 to 100:1, preferably 1:1 to 50: 1.

32. The production method according to any one of claims 1 and 25 to 28, wherein the oxidation reaction solvent is a solvent having a dielectric constant of more than 2.8 at 20 ℃, preferably a solvent having a dielectric constant of more than 2.8 to 50 or less at 20 ℃; more preferably, the oxidation reaction solvent is one or more of aliphatic alcohol with carbon number of 1-4, tetrahydrofuran, acetone, N-alkyl substituted amide and N-alkyl pyrrolidone; wherein the number of alkyl substituents is 1-2, each alkyl substituent is independently C₁-C₄Alkyl groups of (a); most preferably, the oxidation reaction solvent is selected from one or more of methanol, t-butanol, acetone, N-dimethylformamide, N-dimethylacetamide, N-dimethylpropionamide, N-methylpyrrolidone, and N-ethylpyrrolidone;

the total content of the 2-alkylanthracene is 0.1 to 80% by weight, preferably 5 to 50% by weight, based on the total weight of the 2-alkylanthracene and the oxidation reaction solvent.

33. The production method according to any one of claims 1 and 25 to 28, wherein the oxidation reaction solvent is a combination of a solvent a having a dielectric constant of 1 to 10 at 20 ℃ and a solvent B having a dielectric constant of more than 10 to 50 or less at 20 ℃;

the solvent A is C₆Above, preferably C₆-C₁₂Alkane, ring ofOne or more of alkanes and aromatic hydrocarbons; wherein the aromatic hydrocarbon is substituted or unsubstituted, preferably one or more of monobasic or polybasic substituted substances of benzene, more preferably one or more of polybasic substituted substances of benzene, and the substituent is C₁-C₄One or more of alkyl and halogen elements of (a); further preferably, the solvent A is one or more of polyalkyl substituents of benzene, and most preferably, the solvent A is one or more selected from 1,3, 5-trimethylbenzene, 1,2,3, 5-tetramethylbenzene, 1,3,4, 5-tetramethylbenzene, 1,3,5, 6-tetramethylbenzene and 2,3,5, 6-tetramethylbenzene;

the solvent B is N-alkyl substituted amide, wherein the number of alkyl substituents is 1-2, and each alkyl substituent is independently C₁-C₄Alkyl groups of (a); more preferably, the solvent B is selected from one or more of N, N-dimethylformamide, N-dimethylacetamide and N, N-dimethylpropionamide, and most preferably, the solvent B is N, N-dimethylformamide;

34. The method according to claim 33, wherein the volume ratio of solvent a to solvent B is 0.01 to 100, preferably 0.05 to 10.