Production method of coal-based linear alkylbenzene

Abstract

The invention provides a production method of coal-based linear alkylbenzene. The method comprises the following steps: cutting the Fischer-Tropsch synthesis stable heavy oil to obtain distillate oil of C10-C13 and / or distillate oil of C16-C18; and mixing the distillate oil with benzene, adding a chloroaluminate ionic liquid catalyst, carrying out a synthetic reaction to obtain a synthetic feed liquid, and carrying out post-treatment to obtain the coal-based linear alkylbenzene. The distillate oil obtained by cutting the coal-based stable heavy oil fraction is used as the coal-based raw material, a new raw material source is provided, and the product composition is enriched; the chloroaluminate ionic liquid catalyst is used, so that the catalytic efficiency is high, the olefin conversion rate is high, the risks of strong toxicity and strong corrosivity in the production of the linear alkylbenzene in the traditional industry are reduced, the reaction condition is mild, the operation is convenient, the linear alkylbenzene is not easy to inactivate and good in stability, and the service life can be prolonged; the synthesized linear alkylbenzene product has a large density difference from the catalyst, the product layering is obvious, and the separation method is simple and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of coal chemical industry, and in particular to a method for producing coal-based linear alkylbenzene. Background Art

[0002] Linear alkylbenzene is an important intermediate in chemical production, 95% of which is used in the production of surfactants. The alkylbenzene sulfonate generated after sulfonation and neutralization has excellent processability, compatibility and good biodegradability. Alkylbenzene sulfonate has long been widely used as the main component of household and industrial detergents. The synthesis of linear alkylbenzene mainly has four synthetic routes, namely dehydrogenation, chlorination, paraffin cracking and propylene oligomerization, depending on the source of the alkylating agent.

[0003] The alkylbenzenes produced by paraffin cracking are mostly 2-phenylalkane, which is the main component of detergents and has unsatisfactory washing effects. The alkylbenzenes produced by propylene oligomerization are mostly branched alkylbenzenes with poor biodegradability. Currently, the chlorination and dehydrogenation routes using kerosene as the source are the most widely used. Commonly used alkylation catalysts include Lewis acid catalysts, protonic acids or acidic oxides, among which hydrofluoric acid and aluminum chloride are the most widely used catalysts for the production of alkylbenzenes in industry.

[0004] In industry, linear alkylbenzenes are mainly produced by the dehydrogenation-HF method. The raw material is kerosene, which is hydrorefined to remove impurities such as sulfur, nitrogen, oxygen, and metals. The refined oil is dewaxed by molecular sieves to separate normal alkanes, and the normal alkanes are dehydrogenated to obtain monoolefins. The monoolefins react with benzene in the presence of a hydrofluoric acid catalyst, and the alkylated products are distilled to obtain alkylbenzene products at the top of the tower and heavy alkylbenzene products at the bottom of the tower.

[0005] Although hydrofluoric acid and aluminum chloride catalysts have the advantages of mild reaction conditions, simple reactors, and low raw material molar ratios, aluminum chloride catalysts have problems such as low product yield, poor selectivity, and difficulty in separating products, which hinder their use in the alkylbenzene industry. The dehydrogenation-HF method has a long process flow, high requirements for raw materials, and severe corrosion of equipment by hydrofluoric acid catalysts, and it is difficult to separate the product from the catalyst.

[0006] Chinese patent CN108341735A discloses a method for producing linear alkylbenzene, which uses normal alkane olefins containing 2 to 20 carbon atoms in Fischer-Tropsch synthetic oil as raw materials, performs cutting and dealcoholization pretreatment to improve the conversion rate and yield of olefins, and uses a bulkhead tower to react benzene with olefins under certain conditions to obtain C10-C13 alkylbenzene. Chinese patent CN202111625579.7 discloses a method for preparing alkylbenzene, which causes benzene and olefin raw materials to undergo alkylation reaction under the action of a solid acid catalyst to obtain alkylbenzene.

[0007] However, although the solid catalyst used in the above solid acid catalyzed alkylbenzene synthesis scheme has high activity, it is still highly toxic and corrosive, relatively poor in stability, and easily loses activity or is contaminated during the reaction process. Once contaminated, its catalytic activity will decrease rapidly, and it is difficult to regenerate after contamination, and its service life is relatively short. Therefore, the above scheme still cannot solve the above-mentioned problems. Summary of the invention

[0008] The main purpose of the present invention is to provide a method for producing coal-based linear alkylbenzene to solve the problems of limited raw material sources, high catalyst toxicity and corrosiveness, short catalyst service life and difficult product separation in the prior art.

[0009] In order to achieve the above-mentioned object, according to one aspect of the present invention, there is provided a method for producing coal-based linear alkylbenzene, comprising the following steps: step S1, cutting Fischer-Tropsch synthesis stable heavy oil to obtain distillate oil, wherein the distillate oil comprises C10-C13 distillate oil and / or C16-C18 distillate oil; step S2, mixing the distillate oil with benzene to obtain a mixed raw material; step S3, adding a chloroaluminate-type ionic liquid catalyst to the mixed raw material to carry out a synthesis reaction to obtain a synthetic feed liquid; step S4, post-treating the synthetic feed liquid to obtain coal-based linear alkylbenzene.

[0010] Furthermore, the cutting temperature of C10-C13 distillate oil is 180-240°C; and / or in C10-C13 distillate oil, the weight percentage of normal olefins is 35-68%, the weight percentage of normal paraffins is 24-57%, and the balance is other hydrocarbons and oxygen-containing compounds; and / or the cutting temperature of C16-C18 distillate oil is 280-330°C; and / or in C16-C18 distillate oil, the weight percentage of α-olefins is 25-47%, the weight percentage of normal paraffins is 43-65%, and the balance is other hydrocarbons and oxygen-containing compounds.

[0011] Furthermore, step S1 also includes the following steps: adsorbing and deoxygenating the distillate oil to obtain deoxygenated distillate oil; preferably, the adsorbent for adsorption and deoxygenation is one or more of activated carbon, basic alumina, silica gel, kaolin and diatomaceous earth; preferably, the weight ratio of distillate oil to adsorbent is (3-10):1; preferably, the weight percentage of olefins in the deoxygenated distillate oil is 65-75%.

[0012] Furthermore, the chloroaluminate-type ionic liquid catalyst is prepared from the hydrochloride of a quaternary ammonium salt cation and anhydrous aluminum chloride; preferably, the hydrochloride of a quaternary ammonium salt cation is mixed with anhydrous aluminum chloride, and refluxed and stirred under nitrogen protection and water bath conditions to obtain the chloroaluminate-type ionic liquid catalyst; more preferably, the temperature of the water bath is 70 to 90° C., and the reflux stirring time is 2.5 to 3.5 hours.

[0013] Furthermore, the quaternary ammonium salt cation includes one or more of trimethylamine, triethylamine, imidazoles and pyridines; and / or the molar ratio of the hydrochloride of the quaternary ammonium salt cation to anhydrous aluminum chloride is 1:(1-4).

[0014] Furthermore, the molar ratio of olefins in the distillate oil to the chloroaluminate type ionic liquid catalyst is 1:(0.06-0.08).

[0015] Furthermore, the molar ratio of olefins to benzene in the distillate oil is 1:(2-12).

[0016] Furthermore, the synthesis reaction temperature is 20-50° C., and the time is 15-300 min. Preferably, the synthesis reaction is carried out under stirring, and the stirring speed is 500-2000 rpm.

[0017] Furthermore, in step S3, a chloroaluminate-type ionic liquid catalyst is added dropwise to the mixed raw material at a dropping speed of 1 to 10 mL / min.

[0018] Further, the post-treatment includes: step B1, allowing the synthetic liquid to stand and separate to obtain an oil phase; adding water to the oil phase for quenching, alkali washing to neutrality, and drying to obtain a mixture of alkylbenzene sulfonate and benzene; step B2, sequentially distilling and optionally vacuum distilling the mixture of alkylbenzene sulfonate and benzene to obtain coal-based linear alkylbenzene; preferably, the temperature for distilling benzene is 78 to 90°C, the temperature for distilling alkanes is 160 to 240°C; and / or the cutting temperature for vacuum distillation is 280 to 350°C, and the vacuum pressure is 10 to 15 kPa.

[0019] The technical scheme of the present invention is applied, coal-based stable heavy oil is used as raw material, and fraction cutting is performed to obtain fraction oil as coal-based raw material for synthesizing alkylbenzene, which provides a new raw material source and enriches the product composition; chloroaluminate type ionic liquid catalyst is used to catalyze the synthesis of alkylbenzene, which has high catalytic efficiency and high olefin conversion rate, reduces the risk of strong toxicity and strong corrosiveness in the production of linear alkylbenzene in traditional industry, mild reaction conditions, convenient operation, and the above catalyst is not easy to deactivate, has good stability, and can extend the service life; the synthesized linear alkylbenzene product has a large difference in density with the catalyst, the product is clearly stratified, and the separation method is simple and reliable. The present invention provides a method for producing coal-based linear alkylbenzene, which can produce coal-based linear alkylbenzene products with a purity of not less than 97%, meeting the index requirements of linear alkylbenzene in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A production route diagram of coal-based linear alkylbenzene according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] Unless otherwise specified, all materials in the present invention can be prepared by conventional methods in the art or purchased from the market.

[0024] As described in the background of the present invention, the existing technology has the problems of limited raw material sources, high catalyst toxicity and corrosiveness, short catalyst service life, and difficult product separation in the production of coal-based linear alkylbenzene. In order to solve the above problems, in a typical embodiment of the present invention, a method for producing coal-based linear alkylbenzene is provided, comprising the following steps: step S1, cutting the Fischer-Tropsch synthesis stable heavy oil to obtain distillate oil, the distillate oil includes C10-C13 distillate oil and / or C16-C18 distillate oil; step S2, mixing the distillate oil with benzene to obtain a mixed raw material; step S3, adding a chloroaluminate type ionic liquid catalyst to the mixed raw material to carry out a synthesis reaction to obtain a synthetic feed liquid; step S4, post-treating the synthetic feed liquid to obtain coal-based linear alkylbenzene.

[0025] Specifically, the Fischer-Tropsch stable heavy oil is first cut to obtain C10-C13 fraction oil and / or C16-C18 fraction oil; then the fraction oil is mixed with benzene, and a chloroaluminate type ionic liquid catalyst is added to carry out a synthesis reaction, and the synthetic liquid is post-treated to obtain coal-based linear alkylbenzene. In the synthesis process, the Lewis acidity of the chloroaluminate type ionic liquid catalyst and its performance as a catalyst play a role in the alkylation reaction. When Lewis acid is used as a catalyst for the synthesis of alkylbenzene, first, the Lewis acid and olefin form a complex, then it is attacked by the benzene ring to form an unstable intermediate, and finally decomposes to form alkylbenzene. The reaction mechanism is as follows, where R is the alkyl group corresponding to the carbon number in the fraction oil:

[0026]

[0027] The invention uses coal-based stable heavy oil as a raw material, cuts the distillate oil obtained by a real boiling point distillation instrument as a coal-based raw material for synthesizing alkylbenzene, provides a new raw material source, and enriches the product composition; uses a chloroaluminate type ionic liquid catalyst to catalyze the synthesis of alkylbenzene, has high catalytic efficiency, high olefin conversion rate, reduces the risk of strong toxicity and strong corrosiveness in the production of linear alkylbenzene in traditional industry, has mild reaction conditions, is easy to operate, and the catalyst is not easy to deactivate, has good stability, and can extend the service life.

[0028] Moreover, in the present invention, the reactants C10-C13, C16-C18 and other fractions and benzene are two mutually soluble organic liquids, the ionic liquid catalyst is an aqueous phase, and is immiscible with the above organic liquids, i.e., a heterogeneous reaction system, the synthesized linear alkylbenzene product has a large difference in density from the catalyst, the product is clearly stratified after standing, and the separation method is simple and reliable. The present invention provides a method for producing coal-based linear alkylbenzene, which can produce a coal-based linear alkylbenzene product with a purity of not less than 97%, meeting the index requirements of industrial linear alkylbenzene.

[0029] In a preferred embodiment, the cutting temperature of C10-C13 distillate oil is 180-240°C; and / or in C10-C13 distillate oil, the weight percentage of normal olefins is 35-68%, the weight percentage of normal paraffins is 24-57%, and the balance is other hydrocarbons and oxygen-containing compounds; and / or the cutting temperature of C16-C18 distillate oil is 280-330°C; and / or in C16-C18 distillate oil, the weight percentage of α-olefins is 25-47%, the weight percentage of normal paraffins is 43-65%, and the balance is other hydrocarbons and oxygen-containing compounds.

[0030] The present invention can further increase the content of normal olefins and normal alkanes in the raw materials by precisely controlling the cutting temperature of C10-C13 distillate oil and C16-C18 distillate oil, effectively solve the problem of limited raw material sources, and improve the utilization efficiency of coal-based raw materials. Selecting normal olefins and normal alkanes with a specific content as raw materials can not only increase the reactive components, but also reduce the occurrence of side reactions, thereby improving the yield and purity of linear alkylbenzene.

[0031] In order to further improve the purity of the raw materials, in a preferred embodiment, step S1 also includes the following steps: adsorbing and deoxygenating the distillate oil to obtain deoxygenated distillate oil, so as to remove oxygen-containing compounds therein, and other impurities are also partially removed, which is beneficial to further improve the olefin conversion rate; preferably, the adsorbent for adsorption and deoxygenation is one or more of activated carbon, basic alumina, silica gel, kaolin and diatomaceous earth; preferably, the weight ratio of distillate oil to adsorbent is (3-10):1; preferably, the weight percentage of olefins in the deoxygenated distillate oil is 65-75%.

[0032] In the above process, by using a specific adsorbent and treating with a suitable raw material to adsorbent weight ratio, oxygen-containing compounds and other impurities in the distillate oil can be removed, so that the olefin content in the deoxygenated distillate oil is as high as 65-75%. This high-concentration olefin raw material can not only directly increase the reaction activity, but also reduce side reactions, improve the olefin conversion rate and the yield of linear alkylbenzene. In addition, the use of high-purity raw materials can also reduce the requirements for catalysts, creating conditions for the use of ionic liquid catalysts with less toxicity and corrosiveness, thereby further reducing damage to equipment and potential health risks to operators. Moreover, the use of high-purity olefin raw materials can well reduce the content of complex components in the product, and the stratification of the product and the ionic liquid catalyst is more obvious. Through static stratification and subsequent treatment, the separation process of the product can be further simplified and the separation efficiency can be improved.

[0033] In a preferred embodiment, the chloroaluminate-type ionic liquid catalyst is prepared from the hydrochloride of a quaternary ammonium salt cation and anhydrous aluminum chloride; preferably, the hydrochloride of a quaternary ammonium salt cation is mixed with anhydrous aluminum chloride, and refluxed and stirred under nitrogen protection and water bath conditions to obtain the chloroaluminate-type ionic liquid catalyst; more preferably, the temperature of the water bath is 70 to 90° C., and the reflux stirring time is 2.5 to 3.5 hours.

[0034] By using the chloroaluminate type ionic liquid catalyst synthesized by the hydrochloride of quaternary ammonium salt cation and anhydrous aluminum chloride, the efficiency and stability of the catalyst can be further improved. Compared with traditional hydrofluoric acid or aluminum chloride catalyst, the use of ionic liquid catalyst can greatly reduce the toxicity and corrosiveness in the production process, protecting the safety of equipment and operators. Moreover, the ionic liquid catalyst prepared by the above method is more conducive to forming a heterogeneous reaction system with the reactant. After the reaction is completed, the product and the catalyst can be simply separated by standing and stratifying, and the complicated separation steps in the traditional process can be omitted, reducing energy consumption and cost, and improving the purity of the product. At the same time, it is also conducive to the recovery and reuse of the catalyst, further reducing the consumption of raw materials, and improving the economy and environmental protection of the production process.

[0035] By optimizing the type of quaternary ammonium salt cations and regulating the weight ratio of its hydrochloride to anhydrous aluminum chloride, the problems of limited raw material sources, high catalyst hazard and difficult product separation in the production of coal-based linear alkylbenzene can be effectively solved. In a preferred embodiment, the quaternary ammonium salt cations include one or more of trimethylamine, triethylamine, imidazoles and pyridines; and / or the molar ratio of the hydrochloride of the quaternary ammonium salt cation to anhydrous aluminum chloride is 1: (1 to 4).

[0036] The introduction of the above-mentioned quaternary ammonium salt cationic hydrochloride is conducive to the construction of novel ionic liquid catalyst, and compared to traditional catalysts, it can significantly reduce toxicity and corrosivity while maintaining efficient catalytic activity. Moreover, by optimizing the weight ratio of quaternary ammonium salt cationic hydrochloride and anhydrous aluminum chloride, the stability and activity of the catalyst can be further improved, olefin conversion is promoted, and the productive rate of linear alkylbenzene is improved. In addition, the acidity of the ionic liquid catalyst can be regulated by changing the addition of anhydrous aluminum chloride according to actual needs. The hydrochloride of anhydrous aluminum chloride and quaternary ammonium salt cationic is easily hydrolyzed in humid air, and needs to be stored in a glass desiccator to avoid its hydrolysis.

[0037] In a preferred embodiment, the molar ratio of olefins in the distillate oil to the chloroaluminate-type ionic liquid catalyst is 1:(0.06-0.08). The above-mentioned catalyst dosage can not only further improve the selectivity and conversion rate of the reaction, promote the production of high-yield linear alkylbenzenes, but also effectively reduce the side reactions and increased energy consumption caused by excessive catalysts, and improve the utilization efficiency of raw materials. Within the above-mentioned catalyst molar ratio range, the ionic liquid catalyst exhibits more excellent catalytic performance, as well as the characteristics of lower toxicity and lower corrosiveness, which is conducive to improving the production environment and protecting the safety of equipment and operators. In addition, the appropriate molar ratio can also promote good phase separation between the product and the catalyst, simplify the product separation step in the post-processing process, reduce separation energy consumption and cost, and improve product purity.

[0038] In order to better improve the selectivity and conversion rate of the reaction, promote the efficient generation of linear alkylbenzene, reduce the formation of by-products, and optimize the purity and yield of the product, in a preferred embodiment, the molar ratio of olefins to benzene in the distillate oil is 1: (2 to 12), preferably 1: (6 to 12). Within the above range, it is also beneficial to make full use of coal-based raw materials, reduce the corrosion of the catalyst to the equipment and the toxicity of the operating environment through dilution, and improve production conditions. In the product separation stage, the appropriate molar ratio helps to form a clearer two-phase stratification of the product and the catalyst, simplify the product separation process, and reduce the separation energy consumption. At the same time, the activity and stability of the catalyst are better maintained under the above reaction conditions, which is conducive to recycling, reducing raw material consumption, and reducing production costs.

[0039] In a preferred embodiment, the temperature of the synthesis reaction is 20 to 50°C, and the time is 15 to 300 min; preferably, the synthesis reaction is carried out under stirring at a stirring speed of 500 to 2000 rpm. The mild reaction temperature is conducive to reducing the material requirements for the equipment and reducing energy consumption, and can also reduce the potential harm of the catalyst to the environment. The above reaction time is conducive to improving the reaction conversion rate and reducing side reactions and resource waste caused by too long reaction time. Stirring conditions are conducive to promoting uniform mixing of reactants, improving reaction efficiency and product purity, and at the same time helping to form a stable and easily separable heterogeneous system. At the above stirring speed, the stratification of the product and the catalyst is more obvious, which is conducive to further simplifying the subsequent product purification and catalyst recovery process, reducing separation costs, and improving the continuity and economy of the production process.

[0040] Since the reaction of the present invention is an exothermic reaction, it is preferred that the ionic liquid is slowly dripped into the reaction system, and the temperature of the reaction system is controlled to be not higher than the reaction temperature. In a preferred embodiment, in step S3, a chloroaluminate-type ionic liquid catalyst is dripped into the mixed raw material, and the dripping rate is 1-10 mL / min. The slow dripping of the catalyst can achieve effective management of the heat release of the exothermic reaction, reduce the side reactions and safety hazards caused by the sudden rise in temperature, make the reaction proceed under mild and controllable conditions, reduce corrosion to the equipment, and provide a safer working environment for the operator. In addition, the precise dripping rate helps to maintain the stability of the reaction system, promotes uniform contact of the reactants, improves the conversion rate of olefins and the selectivity of linear alkylbenzenes, thereby further improving product quality.

[0041] In a preferred embodiment, the post-treatment comprises: step B1, allowing the synthetic feed liquid to stand for stratification to obtain an oil phase; adding water to the oil phase for quenching, alkali washing to neutrality, and drying to obtain a mixture of alkylbenzene sulfonate and benzene; step B2, distilling the mixture of alkylbenzene sulfonate and benzene and optionally performing vacuum distillation in sequence to obtain coal-based linear alkylbenzene; preferably, the temperature for distilling benzene is 78 to 90°C; the temperature for distilling alkanes is 160 to 240°C; and / or the cutting temperature for vacuum distillation is 280 to 350°C, and the reduced pressure is 10 to 15 kPa. Wherein, when only C10 to C13 fraction oil is used, or when C10 to C13 fraction oil and C16 to C18 fraction oil are used simultaneously, alkylbenzene products and part of heavy alkylbenzene products are obtained after distillation, and then the C10 to C13 alkylbenzene products are separated by vacuum distillation cutting, and the bottom of the kettle is heavy alkylbenzene by-products.

[0042] The post-treatment of the present invention includes the steps of stratification, quenching, alkali washing, drying and distillation. By stratification combined with water quenching and alkali washing in the oil phase, the effective separation of the product and the catalyst can be achieved, the separation process can be simplified, the energy consumption can be reduced, and the pollution of the catalyst residue to the product can be reduced, thereby improving the product quality. The drying step is conducive to improving the stability of the product and provides convenience for subsequent treatment. The above-mentioned distillation and vacuum distillation cutting temperatures can further reduce the side reactions and energy consumption caused by high temperature, and improve the purity and yield of linear alkylbenzene. The present invention can significantly improve the raw material conversion efficiency and simplify the product separation process by optimizing the post-treatment steps, thereby providing strong technical support for the green and efficient production of coal-based linear alkylbenzene.

[0043] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0044] Example 1

[0045] The production route of coal-based linear alkylbenzene is shown in Figure 1 .

[0046] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then activated carbon is used for deoxygenation (the weight ratio of fraction to adsorbent is 6:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 70%.

[0047] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:3): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 80°C, and refluxed and stirred for 3 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0048] (3) Benzene and C10-C13 distillate oil were mixed in a reaction kettle at a molar ratio of 6:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.06 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system was controlled not to exceed 50° C. After the dropwise addition was completed, the reaction system was heated to 50° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 30 minutes.

[0049] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0050] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 80°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-315°C fraction is cut out by vacuum distillation, and the vacuum pressure is 12 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is heavy alkylbenzene by-products.

[0051] Example 2

[0052] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then activated carbon is used for deoxygenation (the weight ratio of fraction to adsorbent is 6:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 70%.

[0053] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:3): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 80°C, and refluxed and stirred for 3 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0054] (3) Benzene and C10-C13 distillate oil were mixed in a reaction kettle at a molar ratio of 8:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.06 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system was controlled not to exceed 50° C. After the dropwise addition was completed, the reaction system was heated to 50° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 30 minutes.

[0055] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0056] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 80°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-315°C fraction is cut out by vacuum distillation, and the vacuum pressure is 12 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is heavy alkylbenzene by-products.

[0057] Example 3

[0058] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then activated carbon is used for deoxygenation (the weight ratio of fraction to adsorbent is 6:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 70%.

[0059] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:3): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 80°C, and refluxed and stirred for 3 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0060] (3) Benzene and C10-C13 distillate oil were mixed in a reaction kettle at a molar ratio of 10:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.06 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system was controlled not to exceed 50° C. After the dropwise addition was completed, the reaction system was heated to 50° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 30 minutes.

[0061] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0062] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 80°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-315°C fraction is cut out by vacuum distillation, and the vacuum pressure is 12 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is heavy alkylbenzene by-products.

[0063] Example 4

[0064] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then activated carbon is used for deoxygenation (the weight ratio of fraction to adsorbent is 6:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 70%.

[0065] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:3): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 80°C, and refluxed and stirred for 3 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0066] (3) Benzene and C10-C13 distillate oil were mixed in a reaction kettle at a molar ratio of 10:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.08 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system was controlled not to exceed 50° C. After the dropwise addition was completed, the reaction system was heated to 50° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 30 minutes.

[0067] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0068] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 80°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-315°C fraction is cut out by vacuum distillation, and the vacuum pressure is 12 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is heavy alkylbenzene by-products.

[0069] Example 5

[0070] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 280-330°C in a real boiling point distiller to obtain C16-C18 fractions. Then activated carbon is used for deoxygenation (the weight ratio of fraction to adsorbent is 6:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 70%.

[0071] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:3): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 80°C, and refluxed and stirred for 3 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0072] (3) Benzene and C16-C18 distillate oil were mixed in a reactor at a molar ratio of 10:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.06 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system was controlled not to exceed 30° C. After the addition was completed, the reaction system was heated to 30° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 15 minutes.

[0073] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0074] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 80°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-315°C fraction is cut out by vacuum distillation, and the vacuum pressure is 12 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is C16-C18 heavy alkylbenzene products.

[0075] Example 6

[0076] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then, deoxygenation is performed using basic alumina (the weight ratio of fraction to adsorbent is 3:1) to remove impurities such as oxides from the fraction. The weight percentage of olefins in the deoxygenated fraction is about 65%.

[0077] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:1): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 90°C, and reflux and stir for 3.5 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0078] (3) Benzene and C10-C13 distillate oil were mixed in a reaction kettle at a molar ratio of 6:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.07 (molar ratio of catalyst to olefins in distillate oil) at a rate of 1 mL / min, and the temperature of the reaction system was controlled not to exceed 50° C. After the dropwise addition was completed, the reaction system was heated to 50° C., the stirring speed was controlled to 2000 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 300 min.

[0079] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0080] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the mixture of unreacted alkanes, alkylbenzene sulfonate and benzene in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 78°C, and the temperature of the second stage is 160-240°C). The benzene in the first stage is recovered and reused, and the alkanes distilled out in the second stage are used as by-products. The remaining products are alkylbenzene products and part of heavy alkylbenzene products. Then, a 280-350°C fraction is cut out by vacuum distillation, and the vacuum pressure is 15 kPa, and C10-C13 alkylbenzene products are separated, and the bottom of the kettle is heavy alkylbenzene by-products.

[0081] Example 7

[0082] (1) Stabilized heavy oil from Fischer-Tropsch synthesis is first cut at 180-240°C in a real boiling point distiller to obtain C10-C13 fractions. Then, silica gel is used for deoxygenation (the weight ratio of fraction to adsorbent is 10:1) to remove impurities such as oxides in the fraction. The weight percentage of olefins in the deoxygenated fraction is about 75%.

[0083] (2) Preparation of chloroaluminate-type ionic liquid catalyst using trimethylammonium hydrochloride and anhydrous aluminum chloride (the molar ratio of the two is 1:4): trimethylammonium hydrochloride is added to a 500 mL three-necked flask equipped with a reflux condenser, the water bath temperature is controlled at 40°C, anhydrous AlCl3 is added to the flask in batches and stirred, and after all the anhydrous AlCl3 is added, the water bath temperature is adjusted to 70°C, and refluxed and stirred for 2.5 hours under nitrogen protection to obtain a chloroaluminate-type ionic liquid catalyst.

[0084] (3) Benzene and C10-C13 distillate oil were mixed in a reactor at a molar ratio of 12:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst was slowly dripped into the reaction system at a molar ratio of 0.07 (molar ratio of catalyst to olefins in distillate oil) at a rate of 10 mL / min, and the temperature of the reaction system was controlled not to exceed 20° C. After the dropwise addition was completed, the reaction system was heated to 20° C., the stirring speed was controlled to 500 rpm, so that it reached thermodynamic equilibrium, and the product was obtained after isothermal reaction for 15 minutes.

[0085] (4) The product is allowed to stand for stratification, and the ionic liquid catalyst in the lower layer is separated. A certain amount of water is added to the upper oil phase to quench the reaction, and the upper oil phase component is washed with a 10% NaOH solution until neutral. Anhydrous magnesium sulfate is added to dry the upper oil phase component. The dark liquid in the lower layer is the ionic liquid catalyst, and the transparent liquid in the upper layer is a mixture of unreacted alkanes, product alkylbenzene sulfonate, and benzene.

[0086] (5) The lower layer of ionic liquid catalyst is recovered and reused, and the unreacted alkane, alkylbenzene sulfonate and benzene mixture in the upper layer is distilled by a distillation apparatus (the temperature of the first stage is 90°C, and the temperature of the second stage is 160-240°C), and the benzene in the first stage is recovered and reused, and the alkane distilled from the second stage is used as a by-product, and the remaining products are alkylbenzene products and part of the heavy alkylbenzene products. Then, the 280-350°C fraction is cut out by vacuum distillation, and the vacuum pressure is 10kPa, and the C10-C13 alkylbenzene products are separated, and the bottom of the kettle is the heavy alkylbenzene by-product.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that the catalyst is hydrofluoric acid.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that in step (3), benzene and C10-C13 distillate oil are mixed in a reaction kettle in a molar ratio of 6:1 (molar ratio of benzene to olefins in distillate oil), and an ionic liquid catalyst is slowly dripped into the reaction system at a molar ratio of 0.04 (molar ratio of catalyst to olefins in distillate oil) at a rate of 2 mL / min, and the temperature of the reaction system is controlled not to exceed 50° C. After the dropwise addition is completed, the reaction system is heated to 50° C., the stirring speed is controlled to 500 rpm, so that it reaches thermodynamic equilibrium, and the product is obtained after isothermal reaction for 30 minutes.

[0091] The composition of the distillate oil, olefin conversion rate and alkylbenzene content in the coal-based linear alkylbenzene in the above examples and comparative examples are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] As can be seen from the above, compared with the comparative example, each embodiment of the present invention uses coal-based stable heavy oil as raw material, and obtains distillate oil as coal-based raw material for synthesizing alkylbenzene after fraction cutting, which provides a new raw material source and enriches the product composition; uses chloroaluminate type ionic liquid catalyst to catalyze alkylbenzene synthesis, with high catalytic efficiency and high olefin conversion rate, reduces the risk of strong toxicity and strong corrosiveness in the production of linear alkylbenzene in traditional industry, mild reaction conditions, convenient operation, and the above catalyst is not easy to deactivate, has good stability, and can extend the service life; the synthesized linear alkylbenzene product has a large difference in density with the catalyst, the product is obviously layered, and the separation method is simple and reliable. The present invention provides a method for producing coal-based linear alkylbenzene, which can produce coal-based linear alkylbenzene products with a purity of not less than 97%, meeting the index requirements of linear alkylbenzene in industry.

[0096] In addition, it can be seen that when each process parameter is within the preferred range of the present invention, the overall effect is better.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for producing coal-based linear alkylbenzene, characterized in that: The following steps are involved: Step S1, cutting the Fischer-Tropsch synthesis stable heavy oil to obtain distillate oil, wherein the distillate oil includes C10-C13 distillate oil and / or C16-C18 distillate oil; Step S2, mixing the distillate oil with benzene to obtain a mixed raw material; Step S3, adding a chloroaluminate-type ionic liquid catalyst to the mixed raw material to perform a synthesis reaction to obtain a synthetic feed solution; Step S4, post-treating the synthetic liquid to obtain the coal-based linear alkylbenzene.

2. The production method according to claim 1, characterized in that The cutting temperature of the C10-C13 distillate oil is 180-240° C.; and / or in the C10-C13 distillate oil, the weight percentage of normal olefins is 35-68%, the weight percentage of normal paraffins is 24-57%, and the balance is other hydrocarbons and oxygen-containing compounds; and / or The cutting temperature of the C16-C18 distillate oil is 280-330° C.; and / or in the C16-C18 distillate oil, the weight percentage of α-olefins is 25-47%, the weight percentage of normal alkanes is 43-65%, and the balance is other hydrocarbons and oxygen-containing compounds.

3. The production method according to claim 1 or 2, characterized in that: The step S1 further comprises the following steps: adsorbing and deoxygenating the distillate oil to obtain deoxygenated distillate oil; Preferably, the adsorbent for adsorption and deoxidation is one or more of activated carbon, basic alumina, silica gel, clay and diatomaceous earth; Preferably, the weight ratio of the distillate oil to the adsorbent is (3-10):1; Preferably, the weight percentage of olefins in the deoxygenated distillate oil is 65-75%.

4. The production method according to any one of claims 1 to 3, characterized in that The chloroaluminate-type ionic liquid catalyst is prepared from hydrochloride of quaternary ammonium salt cations and anhydrous aluminum chloride; Preferably, the hydrochloride of the quaternary ammonium salt cation is mixed with the anhydrous aluminum chloride, and refluxed and stirred under nitrogen protection and water bath conditions to obtain the chloroaluminate type ionic liquid catalyst; More preferably, the temperature of the water bath is 70-90° C., and the reflux stirring time is 2.5-3.5 h.

5. The production method according to claim 4, characterized in that: The quaternary ammonium salt cation includes one or more of trimethylamine, triethylamine, imidazoles and pyridines; and / or the molar ratio of the hydrochloride of the quaternary ammonium salt cation to the anhydrous aluminum chloride is 1:(1-4).

6. The production method according to any one of claims 1 to 5, characterized in that The molar ratio of the olefins in the distillate oil to the chloroaluminate type ionic liquid catalyst is 1:(0.06-0.08).

7. The production method according to any one of claims 1 to 6, characterized in that The molar ratio of the olefins in the distillate oil to the benzene is 1:(2-12).

8. The production method according to any one of claims 1 to 7, characterized in that The temperature of the synthesis reaction is 20-50°C and the time is 15-300min; Preferably, the synthesis reaction is carried out under stirring at a stirring speed of 500 to 2000 rpm.

9. The production method according to any one of claims 1 to 8, characterized in that In the step S3, the chloroaluminate-type ionic liquid catalyst is added dropwise to the mixed raw material at a dropping speed of 1 to 10 mL / min.

10. The production method according to any one of claims 1 to 9, characterized in that The post-processing includes: Step B1, standing the synthetic feed solution for stratification to obtain an oil phase; adding water to the oil phase for quenching, alkali washing to neutrality, and drying to obtain a mixture of alkylbenzene sulfonate and benzene; Step B2, sequentially distilling and optionally distilling under reduced pressure the mixture of the alkylbenzene sulfonate and benzene to obtain the coal-based linear alkylbenzene; Preferably, the temperature for distilling benzene is 78-90°C, the temperature for distilling alkanes is 160-240°C; and / or the cutting temperature for the vacuum distillation is 280-350°C, and the vacuum pressure is 10-15 kPa.

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