CN111825512B

CN111825512B - Process for preparing 2-alkyl anthraquinone

Info

Publication number: CN111825512B
Application number: CN201910300514.1A
Authority: CN
Inventors: 郑博; 宗保宁; 费建奇; 潘智勇; 郄思远; 张月琴; 朱振兴; 毛俊义
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: 2021-07-09
Anticipated expiration: 2039-04-15
Also published as: CN111825512A

Abstract

The invention relates to the field of preparation of 2-alkylanthraquinone, and particularly discloses a preparation method of 2-alkylanthraquinone, wherein the preparation method comprises the following steps: (1) preparing a reaction product containing an alkyl anthracene from an anthracene; (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) preparing 2-alkylanthraquinone from the 2-alkylanthraquinone obtained in step (2). The method provided by the invention opens up a new direction for the green preparation of the 2-alkylanthraquinone, can obviously reduce the separation operation difficulty of a high-boiling point and high-melting point mixture system, and has high separation efficiency, the product purity is 99.5 percent, and the yield is 94.23 percent.

Description

Process for preparing 2-alkyl anthraquinone

Technical Field

The invention relates to a preparation method of an organic matter, in particular to a preparation method of 2-alkylanthraquinone.

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 a method for alkylating anthracene by using ionic liquid catalysis, and the catalytic system of the alkylation reaction is a mixture containing 60-93.7 wt% of ionic liquid and 1-8 wt% of aluminum 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%.

In US3953482 a process for the preparation of a catalyst using H is disclosed₂O₂A 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 preparation method of 2-alkyl anthraquinone based on the prior art, namely an integral process for preparing reaction products containing alkyl anthracene by using anthracene as a raw material through reaction, namely separating and preparing the 2-alkyl anthracene, and preparing the 2-alkyl anthraquinone from the 2-alkyl anthracene through reaction.

The invention provides a preparation method of 2-alkylanthraquinone, wherein the preparation method comprises the following steps:

(1) preparing a reaction product containing an alkyl anthracene from an anthracene;

(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) preparing 2-alkylanthraquinone from the 2-alkylanthraquinone obtained in step (2).

The whole technical route for preparing the 2-alkylanthraquinone by the anthracene is reasonable and feasible, and opens up a new direction for the green preparation of the 2-alkylanthraquinone. The method provided by the invention can obviously reduce the operation difficulty of 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, and has high separation efficiency, so that the total yield of the 2-alkyl anthraquinone is also 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 chart of a process for producing 2-alkylanthraquinone according to one embodiment of 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 preparation method of the 2-alkylanthraquinone comprises the following steps:

According to the present invention, the starting material anthracene can be reacted to produce an anthracene containing an alkyl group. The method of producing an alkyl anthracene-containing reaction product from anthracene can be any single reaction or a combination of multiple steps to introduce an alkyl group into an anthracycline to produce an alkyl anthracene. Substances containing anthracene ring structures in the reaction products obtained in the step (1) comprise residual anthracene, 2-alkyl anthracene and other series alkyl anthracene products. It is well known to those skilled in the art that, depending on the reaction method, if the starting anthracene is not completely converted, the reaction product may 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 one embodiment of the present invention, as shown in fig. 1, the method for preparing 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.

According to the present invention, the conditions and methods of the anthracycline reaction in step (1) may be performed 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 the step (1), the alkylation reaction solvent is an inert organic solvent capable of dissolving anthracene. Specifically, the alkylation reaction solvent is a solvent having a dielectric constant of 1 to 10 at 20 ℃, and more specifically, the alkylation reaction solvent is C₆Above, preferably C₆-C₁₂And one or more of paraffins, naphthenes, and aromatics. Wherein the aromatic hydrocarbon is substituted or unsubstituted, preferably one or more of mono-or multi-substituted benzene; more preferably one or more of benzene multi-substituted compounds, the substituent is C₁-C₄And one or more of an alkyl group and a halogen element. Further preferably, the alkylation reaction solvent is one or more of polyalkyl substituents of benzene. Most preferably, the alkylation reaction solvent 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 amount of the alkylation reaction solvent is only required to ensure that the anthracene can be fully dissolved so as to achieve the effect of providing 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 the step (1), the mode of contacting the anthracene with the alkylating agent under the alkylation conditions and in the presence of the alkylation reaction solvent and the catalyst is not particularly limited, and preferably, in order to ensure that the alkylation reaction can be carried out more favorably, the anthracene, the catalyst and the alkylation reaction solvent are prepared as a raw material solution of the anthracene-catalyst-alkylation reaction solvent, and then the alkylating agent is added to carry out the 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 ℃.

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 may be any form and kind of acid catalyst capable of catalyzing the alkylation of anthracene, for example, the catalyst is selected from one or more of liquid acids, preferably methanesulfonic acid and/or p-toluenesulfonic acid; 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 the amount conventionally used in the art.

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 260 ℃ to 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 220-305 ℃, 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.

Alternatively, the first and second electrodes may be,

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 260 ℃ to 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 220-305 ℃, 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 one embodiment of the present invention, as shown in FIG. 1, in the step (3), the process for producing 2-alkylanthraquinone from 2-alkylanthraquinone obtained via the step (2) is preferably a process for producing 2-alkylanthraquinone by subjecting 2-alkylanthraquinone to oxidation reaction. 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 oxidant under oxidation conditions and in the presence of an oxidation reaction solvent and a catalyst to perform an oxidation reaction.

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 the step (3), the conditions and method of the oxidation reaction may be performed in a manner conventional in the art.

According to the present invention, in the step (3), the oxidizing agent may be various oxidizing agents known to those skilled in the art capable of oxidizing 2-alkylanthracene to produce 2-alkylanthraquinone, for example, the oxidizing agent may be selected from one or more of nitric acid, potassium dichromate, cerium ammonium nitrate, hydrogen peroxide, ozone, oxygen and tert-butyl hydrogen peroxide, preferably from one or more of hydrogen peroxide, ozone, oxygen and tert-butyl hydrogen peroxide, more preferably hydrogen peroxide, the hydrogen peroxide is preferably used in the form of an aqueous hydrogen peroxide solution, the concentration of the aqueous hydrogen peroxide solution is not particularly limited and may be selected conventionally in the art.

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, preferably from 1:1 to 50: 1.

According to the present invention, in the step (3), the oxidation reaction solvent is an inert organic solvent capable of dissolving the 2-alkylanthracene, and preferably, the oxidation reaction solvent is selected from one or more aliphatic alcohols having a carbon number of 1 to 4, preferably methanol. 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 the present invention, in step (3), the oxidation reaction is generally carried out under conditions including: the reaction temperature can be 10-150 ℃, and preferably 20-100 ℃; 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), in order to enable the oxidation reaction to proceed more easily, the oxidation reaction is performed in the presence of a catalyst. Specifically, the catalyst may be one or more of compounds containing a halogen element, and is preferably hydrogen chloride, which is preferably used in the form of an aqueous hydrogen chloride solution, the concentration of which is not particularly limited and may be selected by referring to the routine choice in the art. The amount of catalyst may also be referred to the amounts conventionally used in the art, for example, the molar ratio of oxidant to catalyst is from 0.01:1 to 20:1, preferably from 0.1:1 to 10: 1.

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 an external standard analysis curve by adopting high-purity 2-alkyl anthracene and mesitylene, quantitatively calculating the content of 2-alkyl anthracene in the mixture of anthracene and 2-alkyl anthracene, and marking 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:

examples 1-12 below serve to illustrate the preparation of the 2-alkylanthraquinones provided by the present invention.

Example 1

And (I) alkylation reaction.

The 2-pentylanthracene is prepared by alkylating anthracene and isoamylene, mesitylene is used as a solvent, and methanesulfonic acid is used as a catalyst. 460g of anthracene, 800ml of mesitylene and 42g of methanesulfonic acid 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 light components with boiling points lower than that of anthracene, such as residual isoamylene, mesitylene and the like can be separated out successively. 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 300 ℃, 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 240 ℃, 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 a 5L glass kettle were added 3000ml of methanol, 150g of 2-pentylanthracene, and 307g of 36 wt% hydrochloric acid. 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-tert-amylanthraquinone on the upper layer, and distilling to obtain the final product 2-amylanthraquinone.

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 procedure of example 1, except that after distilling off light components having a boiling point lower than that of anthracene, anthracene was separated not by melt crystallization but directly by distillation under reduced pressure. 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.

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 300 ℃, 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 240 ℃, 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 290 ℃ C., a theoretical plate number of 65 and a head reflux ratio of 1.5. And carrying out fourth reduced pressure distillation on the tower bottom distillate, wherein the tower top pressure is 1KPa, the tower bottom temperature is 305 ℃, the theoretical plate number is 70, and the tower top reflux ratio is 3. And collecting a product 2-pentylanthracene at the top of the tower.

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 300 ℃, 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 240 ℃, 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 280 ℃, 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 overhead distillate, wherein the overhead pressure is 1.2KPa, the bottom temperature is 266 ℃, the number of theoretical plates is 75, and the overhead reflux ratio 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 320 ℃, 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 228 ℃, 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 291 ℃, 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 221 ℃, 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 dosage of the 36 wt% hydrochloric acid is changed to 325g, and the dosage of the hydrogen peroxide (the content of the hydrogen peroxide is 30 wt%) is changed to 363 g.

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 310 ℃, 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 251 ℃, 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 dosage of 36 wt% hydrochloric acid is changed to 290g, and the dosage of hydrogen peroxide is changed to 324g (the content of hydrogen peroxide is 30 wt%).

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 1.

Example 9

And (I) alkylation reaction.

The 2-pentylanthracene is prepared by alkylating anthracene and isoamylene, mesitylene is used as a solvent, and methanesulfonic acid is used as a catalyst. 76g of anthracene, 800ml of mesitylene and 12g of methanesulfonic acid 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.

Both the step (two) and the step (three) were the same as in example 1.

Example 10

And (I) alkylation reaction.

The 2-pentylanthracene is prepared by alkylating anthracene and isoamylene, mesitylene is used as a solvent, and methanesulfonic acid is used as a catalyst. To a 2L stirred tank, 229g of anthracene, 800ml of mesitylene, and 40g of methanesulfonic acid were added at room temperature. After sealing, the temperature is raised to 130 ℃ at the rotation speed of 1000 rpm, and the pressure is 0.2 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.

Both the step (two) and the step (three) were the same as in example 1.

Example 11

Both the step (one) and the step (two) were the same as in example 1. Except that, in step (three), 3000ml of methanol, 266g of 2-pentylanthracene, and 217g of 36 wt% hydrochloric acid were charged into a 10L glass vessel. The reaction was carried out at atmospheric pressure and 65 ℃ and 1216g (30 wt% hydrogen peroxide content) of hydrogen peroxide was added to the kettle by a peristaltic pump 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-tert-amylanthraquinone on the upper layer, and distilling to obtain the final product 2-amylanthraquinone.

Example 12

Both the step (one) and the step (two) were the same as in example 1. Except that, in the third step, 3000ml of methanol, 600g of 2-pentylanthracene, and 490g of 36 wt% hydrochloric acid were charged into a 5L glass vessel. The reaction was carried out at atmospheric pressure and 65 ℃ with a peristaltic pump feeding 274g 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-tert-amylanthraquinone on the upper layer, and distilling to obtain the final product 2-amylanthraquinone.

The results in table 1 show that, in the preparation method of 2-alkylanthraquinone provided by the present invention, by using the melt crystallization-distillation coupling separation technology, the purity of the separated crystal anthracene, the purity of the intermediate product 2-pentylanthracene (2-butylanthracene, 2-hexylanthracene), and the total yield of the separation process of 2-pentylanthracene (2-butylanthracene, 2-hexylanthracene) are significantly improved compared with the prior art, and the total yield of the finally obtained 2-alkylanthraquinone is also improved. 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 preparation method of 2-alkyl anthraquinone, which is characterized by comprising the following steps:

2. The production method according to claim 1, wherein, in the step (1), the method for producing the reaction product containing the alkyl anthracene from the anthracene 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.

3. The method of claim 2, wherein the contacting is performed by: the raw material liquid containing anthracene, catalyst and alkylation reaction solvent is contacted with alkylation reagent to make alkylation reaction.

4. The preparation method according to claim 2 or 3, wherein the alkylating agent is one or more of olefins having 2 to 8 carbon atoms, alcohols, halogenated hydrocarbons and ethers.

5. The preparation method according to claim 4, wherein the alkylating agent is one or more of olefins containing 4 to 6 carbon atoms, alcohols, halogenated hydrocarbons and ethers.

6. The process of claim 5 wherein the alkylating agent is a mono-olefin having from 4 to 6 carbon atoms.

7. The production method according to any one of claims 2,3,5 and 6, wherein in the step (1), the molar ratio of anthracene to the alkylating agent is from 0.2:1 to 20: 1.

8. The production process according to claim 7, wherein in the step (1), the molar ratio of anthracene to the alkylating agent is from 0.5:1 to 5: 1.

9. The production process according to claim 4, wherein in the step (1), the molar ratio of anthracene to the alkylating agent is from 0.2:1 to 20: 1.

10. The production method according to claim 9, wherein in the step (1), the molar ratio of anthracene to the alkylating agent is 0.5:1 to 5: 1.

11. The production process according to claim 2 or 3, wherein in the step (1), the alkylation reaction solvent is a solvent having a dielectric constant of 1 to 10 at 20 ℃, and the alkylation reaction solvent is C₆One or more of the above paraffins, naphthenes and aromatics; wherein the aromatic hydrocarbon is substituted or unsubstituted, and the substituent is C₁-C₄One or more of alkyl and halogen elements of (a);

based on the total weight of anthracene and alkylation reaction solvent, the content of anthracene is 5-60 wt%.

12. The method of claim 11, wherein the alkylation reaction solvent is C₆-C₁₂One or more of paraffins, naphthenes and aromatics;

based on the total weight of anthracene and alkylation reaction solvent, the content of anthracene is 8-50 wt%.

13. The method of claim 12, wherein the aromatic hydrocarbon is one or more of a mono-or multi-substituted benzene.

14. The method of claim 13, wherein the aromatic hydrocarbon is one or more of a poly-substituted benzene.

15. The process of claim 14 wherein the alkylation reaction solvent is one or more of a polyalkyl substituent of benzene.

16. The method of claim 15, wherein the alkylation reaction solvent 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.

17. The production method according to any one of claims 2,3,5,6, 8 to 10 and 12 to 16, wherein in the step (1), the alkylation reaction conditions include: the reaction temperature is 100-250 ℃; the reaction pressure is 0-1 MPa; the reaction time is 0.01-48 h.

18. The method according to claim 17, wherein in the step (1), the alkylation reaction conditions include: the reaction temperature is 120-200 ℃; the reaction pressure is 0.05-0.5 MPa; the reaction time is 0.5-24 h.

19. The preparation method according to claim 4, wherein in the step (1), the alkylation reaction conditions include: the reaction temperature is 100-250 ℃; the reaction pressure is 0-1 MPa; the reaction time is 0.01-48 h.

20. The method of claim 7, wherein the alkylation reaction conditions comprise: the reaction temperature is 100-250 ℃; the reaction pressure is 0-1 MPa; the reaction time is 0.01-48 h.

21. The method of claim 11, wherein the alkylation reaction conditions comprise: the reaction temperature is 100-250 ℃; the reaction pressure is 0-1 MPa; the reaction time is 0.01-48 h.

22. The production method according to any one of claims 19 to 21, wherein in the step (1), the alkylation reaction conditions include: the reaction temperature is 120-200 ℃; the reaction pressure is 0.05-0.5 MPa; the reaction time is 0.5-24 h.

23. The production method according to any one of claims 2,3,5,6, 8 to 10 and 12 to 16, wherein, in the step (1), the catalyst is selected from one or more of liquid acids; the catalyst content is 0.01-50 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

24. The production method according to claim 23, wherein, in the step (1), the catalyst is methanesulfonic acid and/or p-toluenesulfonic acid; the catalyst content is 0.5-30 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

25. The production method according to claim 4, wherein, in the step (1), the catalyst is selected from one or more of liquid acids; the catalyst content is 0.01-50 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

26. The production method according to claim 7, wherein, in the step (1), the catalyst is selected from one or more of liquid acids; the catalyst content is 0.01-50 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

27. The production method according to claim 11, wherein, in the step (1), the catalyst is selected from one or more of liquid acids; the catalyst content is 0.01-50 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

28. The production method according to any one of claims 25 to 27, wherein in step (1), the catalyst is methanesulfonic acid and/or p-toluenesulfonic acid; the catalyst content is 0.5-30 wt% based on the total weight of the raw material liquid containing anthracene, catalyst and alkylation reaction solvent.

29. The production method according to any one of claims 1 to 3,5,6, 8 to 10, 12 to 16, 18 to 21, and 24 to 27, 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.

30. The production method according to claim 4, 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:

31. The production method according to claim 7, 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:

32. The production method according to claim 11, 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:

33. The production method according to claim 17, 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:

34. The production method according to claim 22, 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:

35. The production method according to claim 23, 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:

36. The production method according to claim 28, 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:

37. The preparation method as claimed in claim 29, wherein, in the step (2-2), the melting temperature is 200-270 ℃.

38. The preparation method as claimed in claim 37, wherein, in the step (2-2), the melting temperature is 210-250 ℃.

39. The production method according to any one of claims 30 to 36, wherein, in the step (2-2), the melting temperature is 200 ℃ and 270 ℃.

40. The preparation method as claimed in claim 39, wherein, in the step (2-2), the melting temperature is 210-250 ℃.

41. The preparation method as claimed in any one of claims 30 to 38 and 40, wherein, in the step (2-2), the cooling crystallization temperature is 180 ℃ to 210 ℃, the cooling rate of the cooling crystallization is 0.1 to 10 ℃/h, and the cooling crystallization time is 1 to 5 h.

42. The preparation method as claimed in claim 41, wherein, in the step (2-2), the cooling crystallization temperature is 190-200 ℃, the cooling rate of the cooling crystallization is 0.5-5 ℃/h, and the cooling crystallization time is 1.5-4 h.

43. The method as claimed in claim 29, 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.

44. The preparation method as claimed in claim 39, 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.

45. The preparation method as claimed in claim 43 or 44, wherein, in the step (2-2), the cooling crystallization temperature is 190-200 ℃, the cooling rate of the cooling crystallization is 0.5-5 ℃/h, and the cooling crystallization time is 1.5-4 h.

46. The production method according to any one of claims 42 to 44, wherein in the step (2-2), during the cooling crystallization, a step of adding seed anthracene in an amount of 0.1 to 10% by weight based on the mass of the molten mixture is further included.

47. The production method according to claim 46, wherein the seed anthracene is added in an amount of 0.2 to 5 wt% based on the mass of the molten mixture.

48. The production method according to claim 41, wherein in the step (2-2), in the cooling crystallization, a step of adding seed anthracene in an amount of 0.1 to 10 wt% based on the mass of the molten mixture is further included.

49. The production method according to claim 45, wherein in the step (2-2), in the cooling crystallization, a step of adding seed anthracene in an amount of 0.1 to 10 wt% based on the mass of the molten mixture is further included.

50. The production method according to claim 48 or 49, wherein the seed anthracene is added in an amount of 0.2 to 5 wt% based on the mass of the molten mixture.

51. The production method according to any one of claims 30 to 38 and 40, 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; the temperature is raised to a temperature at which sweating stops and is lower than the melting temperature of the anthracene crystal.

52. The production process according to claim 51, wherein in the step (2-2), the temperature increase rate at which the anthracene crystal is subjected to sweating is 0.2 to 4 ℃/h; the temperature is raised to a temperature of less than or equal to 210 ℃ at which sweating ceases.

53. The production process according to claim 52, wherein in the step (2-2), the sweating is stopped when the temperature is raised to 5 to 15 ℃ higher than the cooling crystallization temperature and lower than 210 ℃.

54. The method as set forth in claim 53, wherein the sweating completion temperature is 190-210 ℃.

55. The method as claimed in claim 54, wherein the sweating completion temperature is 195-205 ℃.

56. The production method according to claim 29, 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; the temperature is raised to a temperature at which sweating stops and is lower than the melting temperature of the anthracene crystal.

57. The production process according to claim 39, 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; the temperature is raised to a temperature at which sweating stops and is lower than the melting temperature of the anthracene crystal.

58. The production method according to claim 56 or 57, wherein in the step (2-2), the temperature increase rate at which the anthracene crystal is subjected to sweating is 0.2 to 4 ℃/h; the temperature is raised to a temperature of less than or equal to 210 ℃ at which sweating ceases.

59. The production process according to claim 58, wherein in the step (2-2), the sweating is stopped when the temperature is raised to 5 to 15 ℃ higher than the cooling crystallization temperature and lower than 210 ℃.

60. The method as claimed in claim 59, wherein the sweating end temperature is 190-210 ℃.

61. The method as claimed in claim 60, wherein the sweating completion temperature is 195-205 ℃.

62. The production method according to any one of claims 52 to 57 and 59 to 61, wherein the amount of perspiration is 5 to 40% by weight based on the mass of the anthracene crystal.

63. The method according to claim 62, wherein the amount of perspiration is 10 to 30 wt% based on the mass of the anthracene crystal.

64. The production method according to claim 51, wherein the amount of perspiration is 5 to 40% by weight based on the mass of the anthracene crystal.

65. The production method according to claim 58, wherein the amount of perspiration is 5 to 40% by weight based on the mass of the anthracene crystal.

66. The production method according to claim 64 or 65, wherein the amount of perspiration is 10 to 30% by weight based on the mass of the anthracene crystal.

67. The production method of any one of claims 52 to 57 and 59 to 61, wherein the method further comprises circulating sweat back to the melt crystallization step to perform melt crystallization together with the reaction product containing alkyl anthracene.

68. The method of claim 51, wherein the method further comprises recycling sweat back to the melt crystallization step for melt crystallization with the reaction product comprising alkyl anthracene.

69. The method of claim 58, further comprising recycling sweat back to the melt crystallization step for melt crystallization with the reaction product comprising alkyl anthracene.

70. The production method according to claim 29, 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.

71. The production method according to any one of claims 30 to 36, 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.

72. The production method according to claim 29, 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 having the highest boiling point and the substance having the lowest boiling point in the mixture; then carrying out multi-step reduced pressure distillation, wherein the multi-step reduced pressure distillation method comprises the following steps:

mode 1:

carrying out first reduced pressure 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; carrying out second reduced pressure distillation on the distillate containing the light component Cj 1-anthracene to obtain a distillate containing the light component Cj 3-anthracene and a bottom product containing the target product Ci-anthracene;

alternatively, the first and second electrodes may be,

mode 2:

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

73. The production method according to any one of claims 30 to 36, 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 having the highest boiling point and the substance having the lowest boiling point in the mixture; then carrying out multi-step reduced pressure distillation, wherein the multi-step reduced pressure distillation method comprises the following steps:

mode 1:

alternatively, the first and second electrodes may be,

mode 2:

74. The production method according to claim 72, 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-.

75. The production method according to claim 74, 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 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.

76. The production process according to claim 75, wherein in the multi-step vacuum distillation step, mode 1, the conditions of the first vacuum distillation include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 260-320 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-3.

77. The production method according to claim 73, 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-.

78. The production method according to claim 77, 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 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.

79. The production method according to claim 78, 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 0.5-2KPa, the temperature at the bottom of the distillation tower is 260-320 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-3.

80. The production method according to any one of claims 72 and 74 to 79, wherein in the multi-step reduced pressure distillation step, the conditions of the second reduced pressure distillation in mode 1 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.

81. The production method according to claim 80, wherein in the multi-step reduced pressure distillation step, the conditions of the second reduced pressure distillation in mode 1 include: 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.

82. The production process according to claim 81, 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 0.5-2KPa, the temperature at the bottom of the distillation tower is 220-305 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-5.

83. The production method according to claim 73, wherein in the multi-step reduced pressure distillation step, the conditions of the second reduced pressure distillation in mode 1 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.

84. The production method according to claim 83, 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 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.

85. The production process according to claim 84, wherein, in the multi-step reduced pressure distillation step, the conditions of the second reduced pressure distillation in mode 1 include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 220-305 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-5.

86. The production process according to claim 72, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum 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-.

87. The production process according to claim 86, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum distillation include: 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.

88. The production process according to claim 87, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum distillation include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 260-320 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-3.

89. The production process according to claim 73, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum 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-.

90. The production process according to claim 89, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum distillation include: 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.

91. The production process according to claim 90, wherein in the multi-step vacuum distillation step, mode 2, the conditions of the third vacuum distillation include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 260-320 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-3.

92. The production method according to any one of claims 72 and 86 to 91, 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.

93. The production method according to claim 92, 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 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.

94. The production process according to claim 93, wherein in the multi-step vacuum distillation step, mode 2, the fourth vacuum distillation conditions include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 220-305 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-5.

95. The production method according to claim 73, wherein in the multi-step reduced pressure distillation step, mode 2, the fourth reduced pressure distillation condition includes: 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.

96. The production process according to claim 95, wherein, in the multi-step vacuum distillation step, mode 2, the fourth vacuum distillation conditions include: 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.

97. The production process according to claim 96, wherein, in the multi-step vacuum distillation step, mode 2, the fourth vacuum distillation conditions include: the pressure at the top of the distillation tower is 0.5-2KPa, the temperature at the bottom of the distillation tower is 220-305 ℃, the number of theoretical plates is 40-75, and the reflux ratio at the top of the distillation tower is 1-5.

98. The production method according to any one of claims 30 to 38, 40, 42 to 44, 47 to 49, 52 to 57, 59 to 61, 63 to 65, 68 to 70, 72, 74 to 79, 81 to 91, and 93 to 97, wherein the reaction product containing an alkylanthracene obtained through step (1) further contains a reaction solvent;

the step (2) further comprises: a step (2-1) of separating the 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 the reaction solvent and a tower bottom product containing anthracene and a series of alkyl anthracene products containing 2-alkyl anthracene.

99. The production method according to claim 29, wherein the reaction product containing an alkyl anthracene obtained through step (1) further contains a reaction solvent;

100. The production method according to claim 39, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

101. The production method according to claim 41, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

102. The production method according to claim 45, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

103. The production method according to claim 46, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

104. The production method according to claim 50, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

105. The production method according to claim 51, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

106. The production method according to claim 58, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

107. The production method according to claim 62, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

108. The production method according to claim 66, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

109. The production method according to claim 67, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

110. The production method according to claim 71, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

111. The production method according to claim 73, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

112. The production method according to claim 80, wherein the reaction product containing an alkyl anthracene obtained through the step (1) further contains a reaction solvent;

113. The production method according to claim 92, wherein the reaction product containing an alkyl anthracene obtained through step (1) further contains a reaction solvent;

114. The production method according to claim 98, wherein in the step (2-1), the conditions of distillation include: the bottom temperature of the distillation tower is 100-300 ℃, and the pressure of the top of the distillation tower is normal pressure.

115. The method as recited in claim 114, wherein the distillation column bottom temperature is 150-200 ℃.

116. The production method according to any one of claims 99 to 113, wherein in the step (2-1), the distillation conditions include: the bottom temperature of the distillation tower is 100-300 ℃, and the pressure of the top of the distillation tower is normal pressure.

117. The method as recited in claim 116, wherein the distillation column bottom temperature is 150-200 ℃.

118. The production method according to claim 1, wherein, in the step (3), the method 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 oxidant under oxidation conditions and in the presence of an oxidation reaction solvent and a catalyst to perform an oxidation reaction.

119. The method of claim 118, 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.

120. The production method according to claim 118 or 119, wherein in the step (3), the oxidation reaction conditions include: the reaction temperature is 10-150 ℃; the reaction pressure is 0-1 MPa; the reaction time is 0.01-48 h.

121. The method according to claim 120, wherein in the step (3), the oxidation reaction conditions include: the reaction temperature is 20-100 ℃; the reaction pressure is 0-0.5 MPa; the reaction time is 0.5-24 h.

122. The method according to any one of claims 118, 119 and 121, wherein in step (3), the oxidizing agent is selected from one or more of nitric acid, potassium dichromate, cerium ammonium nitrate, hydrogen peroxide, ozone, oxygen, and tert-butyl hydroperoxide; the molar ratio of the oxidant to the 2-alkyl anthracene is 0.01:1-100: 1.

123. The method according to claim 122, wherein in the step (3), the oxidizing agent is one or more selected from hydrogen peroxide, ozone, oxygen and tert-butyl hydroperoxide; the molar ratio of the oxidant to the 2-alkyl anthracene is 1:1-50: 1.

124. The production method according to claim 123, wherein, in step (3), the oxidizing agent is hydrogen peroxide, and the hydrogen peroxide is used in the form of an aqueous hydrogen peroxide solution.

125. The method according to claim 120, wherein in the step (3), the oxidizing agent is one or more selected from nitric acid, potassium dichromate, ammonium cerium nitrate, hydrogen peroxide, ozone, oxygen, and tert-butyl hydroperoxide; the molar ratio of the oxidant to the 2-alkyl anthracene is 0.01:1-100: 1.

126. The method according to claim 125, wherein in the step (3), the oxidizing agent is one or more selected from hydrogen peroxide, ozone, oxygen and tert-butyl hydroperoxide; the molar ratio of the oxidant to the 2-alkyl anthracene is 1:1-50: 1.

127. The production method according to claim 126, wherein, in the step (3), the oxidizing agent is hydrogen peroxide, and the hydrogen peroxide is used in the form of an aqueous hydrogen peroxide solution.

128. The production method according to any one of claims 118, 119 and 121, wherein in the step (3), the oxidation reaction solvent is selected from one or more of aliphatic alcohols having a carbon number of 1 to 4; the content of 2-alkylanthracene is 0.1 to 80% by weight based on the total weight of the 2-alkylanthracene and the oxidation reaction solvent.

129. The process according to claim 128, wherein in the step (3), the solvent for the oxidation reaction is methanol; the content of 2-alkylanthracene is 5 to 50% by weight based on the total weight of 2-alkylanthracene and the oxidation reaction solvent.

130. The production process according to claim 120, wherein in the step (3), the oxidation reaction solvent is one or more selected from aliphatic alcohols having a carbon number of 1 to 4; the content of 2-alkylanthracene is 0.1 to 80% by weight based on the total weight of the 2-alkylanthracene and the oxidation reaction solvent.

131. The process according to claim 130, wherein in the step (3), the oxidation reaction solvent is methanol; the content of 2-alkylanthracene is 5 to 50% by weight based on the total weight of 2-alkylanthracene and the oxidation reaction solvent.

132. The production method according to any one of claims 118, 119 and 121, wherein in the step (3), the catalyst is hydrogen chloride, the hydrogen chloride is used in the form of an aqueous hydrogen chloride solution, and the molar ratio of the oxidizing agent to the catalyst is from 0.01:1 to 20: 1.

133. The method of claim 132, wherein the molar ratio of oxidant to catalyst is from 0.1:1 to 10: 1.

134. The process of claim 120, wherein in step (3), the catalyst is hydrogen chloride, the hydrogen chloride is used in the form of aqueous hydrogen chloride solution, and the molar ratio of oxidant to catalyst is from 0.01:1 to 20: 1.

135. The method of claim 134, wherein the molar ratio of oxidant to catalyst is from 0.1:1 to 10: 1.