Organosilica zeolite catalysts and methods for making the same, methods for making heavy alkylbenzenes

Abstract

The application relates to the field of catalysts, and discloses a silicic zeolite catalyst, a preparation method thereof, and a preparation method of heavy alkylbenzene, which comprises the following steps: (1) mixing a silicon source, an aluminum source, an alkali source, a template agent and water to obtain a mixture; the silicon source comprises an organic silicon source and an inorganic silicon source; (2) performing hydrothermal crystallization on the mixture, filtering and drying to obtain a solid product; (3) modifying the solid product by using a cation exchange resin in the presence of a solvent to obtain H-type silicic zeolite, wherein the content of alkali metal in the H-type silicic zeolite is not more than 0.1% by weight; and (4) mixing the H-type silicic zeolite with a binder and / or a binder precursor to form a shape, and performing drying and calcination to obtain the silicic zeolite catalyst. The silicic zeolite catalyst has strong coke capacity and good stability, and in the process of catalyzing the alkylation reaction of linear alkylbenzene and linear olefin to prepare heavy alkylbenzene, the product has high linearity, and the catalyst has a long service life.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to an organosilicon zeolite catalyst and its preparation method, and a method for preparing heavy alkylbenzenes. Background Technology

[0002] Heavy alkylbenzenes are primarily a byproduct of long-chain alkylbenzene plants used in detergents and can be used as lubricating oil additives, heat transfer oils, enhanced oil recovery (EOR) agents, and rubber fillers. In existing technologies, the catalysts used in long-chain alkylbenzene plants mainly employ HF acid and aluminum trichloride. During the alkylation reaction of straight-chain olefins with benzene, several side reactions occur, such as polymerization, isomerization, chain scission disproportionation, and dialkylation. The products of these side reactions are heavy alkylbenzenes. Typically, the yield of heavy alkylbenzenes accounts for only 5% of the total product. Currently, alkylbenzene plants in China all use the HF method. Because HF is toxic, it causes equipment corrosion and poses a significant environmental hazard, making the operation and maintenance of these plants quite complicated. Compared to liquid acid catalysts, solid acid catalysts have higher activity and selectivity for various chemical reactions, are non-toxic, do not easily corrode equipment, are regenerable and recyclable, are environmentally friendly, and have broad industrial application prospects. Therefore, using solid acid catalysts to prepare heavy alkylbenzenes has become a solution to this problem.

[0003] Due to the high toxicity of benzene, Europe has banned the use of heavy alkylbenzenes produced from benzene, and the production of heavy alkylbenzenes using toluene and xylene will become the main production method. CN113578354A proposes the use of macroporous SO4 / ZrO2-SiO2 / Al2O3 catalysts to produce alkylbenzenes from toluene or xylene with straight-chain olefins, where the straight-chain olefins are C24-C42-O3. 15 -C 25 Straight-chain olefins. These solid superacid catalysts, while exhibiting good initial catalytic activity, have an active component, SO42-. 2- It is easily lost during the reaction, which still poses a problem for industrial applications. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low yield and short catalyst life of existing technologies, and to provide an organosilicon zeolite catalyst and its preparation method, as well as a method for preparing heavy alkylbenzenes. The organosilicon zeolite catalyst has high catalytic activity and long life.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing an organosilicon zeolite catalyst, comprising the following steps:

[0006] (1) A mixture is obtained by mixing a silicon source, an aluminum source, an alkali source, a template agent and water; wherein the silicon source includes an organosilicon source and an inorganic silicon source;

[0007] (2) The mixture is subjected to hydrothermal crystallization, filtered and dried to obtain a solid product;

[0008] (3) In the presence of a solvent, the solid product is modified with a cation exchange resin to obtain H-type organosilicon zeolite, wherein the alkali metal content in the H-type organosilicon zeolite does not exceed 0.1% by weight.

[0009] (4) The H-type organosilicon zeolite is mixed with a binder and / or a binder precursor, and then dried and calcined to obtain the organosilicon zeolite catalyst.

[0010] The second aspect of the present invention provides an organosilicon zeolite catalyst prepared by the above preparation method.

[0011] A third aspect of the present invention provides a method for preparing heavy alkylbenzene, wherein a straight-chain alkylbenzene is contacted with a straight-chain olefin in the presence of a catalyst to carry out an alkylation reaction to obtain the heavy alkylbenzene;

[0012] The catalyst is the organosilicon zeolite catalyst mentioned above.

[0013] The beneficial effects obtained by the present invention through the above technical solution are as follows:

[0014] (1) The method for preparing the organosilicon zeolite catalyst provided by the present invention, on the one hand, uses cation exchange resin for modification treatment to obtain H-type organosilicon zeolite in one step, avoiding the subsequent ammonium exchange process; on the other hand, it increases the activity of the catalyst, enhances its coke-holding capacity, and further improves the stability of the catalyst. At the same time, the cation exchange resin after the reaction can be recycled and regenerated, which is beneficial to reducing production costs and is environmentally friendly.

[0015] (2) The method for preparing heavy alkylbenzene provided by this invention uses straight-chain alkylbenzene and straight-chain olefins as raw materials. The production process has low environmental impact, high product selectivity, high product linearity, long catalyst life, and is easy to regenerate. The reaction can be carried out in a fixed-bed reactor, the catalyst will not corrode the equipment, and the process is simple and environmentally friendly. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] The first aspect of this invention provides a method for preparing an organosilicon zeolite catalyst, comprising the following steps:

[0018] (1) A mixture is obtained by mixing a silicon source, an aluminum source, an alkali source, a template agent and water; wherein the silicon source includes an organosilicon source and an inorganic silicon source;

[0019] (2) The mixture is subjected to hydrothermal crystallization, filtered and dried to obtain a solid product;

[0020] (3) In the presence of a solvent, the solid product is modified with a cation exchange resin to obtain H-type organosilicon zeolite, wherein the alkali metal content in the H-type organosilicon zeolite does not exceed 0.1 wt%.

[0021] (4) The H-type organosilicon zeolite is mixed with a binder and / or a binder precursor, and then dried and calcined to obtain the organosilicon zeolite catalyst.

[0022] Traditional methods for preparing H-type molecular sieves often require the use of excessive ammonium salts, resulting in the discharge of large amounts of wastewater with high ammonia nitrogen content, posing significant challenges to wastewater treatment and consuming substantial water resources. In this invention, the combined use of organosilicon and inorganic silicon sources helps optimize the layer structure of organosilicon zeolite, improving the catalytic performance and stability of the catalyst in the synthesis of heavy alkylbenzenes. Furthermore, the use of cation exchange resin to obtain H-type organosilicon zeolite can, on the one hand, regulate the acid properties and acid distribution of the organosilicon zeolite catalyst, increasing the total amount of Brønsted acid; on the other hand, it removes amorphous substances from the pores of the organosilicon zeolite, fully exposing the previously covered active centers, thus modifying the molecular sieve pores. This increases the activity of the organosilicon zeolite catalyst, enhances its coke-holding capacity, and improves its stability.

[0023] Meanwhile, no additional ions are generated during the modification process, and the cation exchange resin can be recycled, saving a large amount of exchange waste liquid and environmental pollution.

[0024] Preferably, the method provided by the present invention does not include ammonium exchange.

[0025] In this invention, the alkali metal content is tested by ICP.

[0026] In this invention, there are no special limitations on the specific operation and conditions of the modification treatment, and conventional methods in the art can be used, as long as the alkali metal content in the organosilicon zeolite can be reduced to below 0.1 wt%. Adjustments can be made according to experimental and production requirements. For example, the solid product can be directly impregnated in a solution containing cation exchange resin, or the solid product obtained in step (2) and the cation exchange resin can be placed on both sides of a porous membrane in the presence of a solvent for modification treatment.

[0027] According to the present invention, the pore size of the porous membrane can be adjusted according to actual needs, as long as it allows solvents and cations to pass through while blocking solid product particles from the cation exchange resin. Preferably, the pore size of the membrane is 0.01-10 μm.

[0028] In this invention, preferably, the amount of cation exchange resin used relative to 1g of the solid product is such that the total acid content of the cation exchange resin is not less than 1mmol, more preferably not less than 2mmol, and even more preferably 2-12mmol.

[0029] In this invention, in order to further reduce the alkali metal content in H-type organosilicon zeolite, the modification treatment can be repeated two to three times until the alkali metal content of the molecular sieve is less than 0.1%.

[0030] According to a preferred embodiment of the present invention, the conditions for the modification treatment include: a reaction temperature of 10-90°C, preferably 20-50°C; and a reaction time of 0.5-4h, preferably 0.5-1h.

[0031] The preferred embodiments described above are beneficial for sodium ion exchange and for maintaining the pore structure of the molecular sieve.

[0032] According to the present invention, there is no particular limitation on the specific type of cation exchange resin, and any conventional choice in the art can be made. For example, the cation exchange resin can be a strong acid cation exchange resin and / or a weak acid cation exchange resin, preferably a strong acid cation exchange resin; the strong acid cation exchange resin is a cation exchange resin having a strong acid group, such as sulfonic acid group -SO3H, etc.

[0033] Preferably, the strongly acidic cation exchange resin is a strongly acidic styrene-based cation exchange resin and / or a strongly acidic acrylic-based cation exchange resin.

[0034] In this invention, the solvent can be selected from any conventional solvent in the art, and preferably, the solvent is water.

[0035] In this invention, preferably, in the modification treatment, the mass ratio of the solvent to the cation exchange resin is 1-20:1, more preferably 1.5-5:1; adopting the above preferred embodiments is beneficial to the exchange of alkali metal ions and the maintenance of the pore structure.

[0036] According to the present invention, preferably, step (3) further includes washing, solid-liquid separation and drying of the modified product to obtain the modified zeolite molecular sieve.

[0037] The separation and washing processes described above are conventional operations in the art and are well known to those skilled in the art. The present invention does not specifically limit the particular operation of these processes. For example, the separation can be performed by standing or by filtration; the washing liquid in the washing process can be water.

[0038] In this invention, the drying process during the modification treatment can be carried out using conventional operations and conditions in the art. Preferably, the drying temperature is 100-200℃, more preferably 120-160℃; and the drying time is 2-48h, more preferably 12-24h.

[0039] Preferably, step (3) does not include a calcination process. By adopting the above-described preferred embodiment, the preparation process can be shortened, while avoiding the increase in pore volume of the organosilicon zeolite caused by calcination.

[0040] According to the present invention, the amount of each component in step (1) can be adjusted according to actual needs. Preferably, the molar ratio of silicon source, aluminum source, alkali source, template agent and water in step (1) is 10:(0.2-2):(5-30):(0.6-10):(20-300), more preferably 10:(0.6-0.9):(14-18):(1-3):(40-200), wherein the silicon source is calculated as SiO2, the aluminum source is calculated as Al2O3, and the alkali source is calculated as OH-; under the above preferred conditions, it is conducive to the formation of the organosilicon zeolite layered structure.

[0041] According to the present invention, there are no special requirements for the mixing method in step (1). Those skilled in the art can make appropriate selections according to the actual situation, as long as the uniform mixing of each component can be achieved. For example, mixing can be carried out by stirring. Preferably, the mixing temperature in step (1) is 0-40℃, more preferably 4-15℃. The above preferred embodiment is beneficial to the control of grain size.

[0042] According to the present invention, the selection range of the silicon source, aluminum source, alkali source and template agent is relatively wide, and they can be conventional choices in the art.

[0043] In this invention, to further improve the catalytic performance of the catalyst, preferably, the molar ratio of the organosilicon source to the inorganic silicon source, based on silicon elemental composition, is 0.005-0.2:1; more preferably, it is 0.008-0.1:1. The introduction of an appropriate amount of organosilicon source helps optimize the structure of the organosilicon zeolite, obtains suitable pore volume, and helps to further improve the catalytic activity and stability of the organosilicon zeolite catalyst.

[0044] According to the present invention, the specific types of the organosilicon source and inorganic silicon source are selected from a wide range and can be conventional choices in the art. Preferably, the organosilicon source is selected from at least one of halosilanes, silazanes, and alkoxysilanes; more preferably, the halosilane is selected from at least one of trimethylchlorosilane, dimethyldichlorosilane, triethylchlorosilane, diethyldichlorosilane, dimethylchlorobromosilane, and dimethylethylchlorosilane; more preferably, the silazane is selected from at least one of hexamethyldisilazane, heptamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, and diphenyltetramethyldisilazane; more preferably, the alkoxysilane is selected from at least one of trimethylethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, dimethyldimethoxysilane, and trimethoxyphenylsilane; preferably, the inorganic silicon source is selected from at least one of solid silicon oxide, silicate esters, silica sol, and water glass, more preferably silica sol and / or water glass.

[0045] In this invention, there are no special limitations on the specific types of the aluminum source, alkali source, and template agent; all are conventional choices in the art. Preferably, the aluminum source is selected from at least one of metal aluminates, metal metaaluminates, aluminum powder, kaolin, montmorillonite, and alumina.

[0046] Preferably, the alkali source is an inorganic alkali; more preferably, it is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and calcium hydroxide.

[0047] Preferably, the template agent is an organic amine template agent, and more preferably at least one selected from ethylenediamine, hexamethylenediamine, cyclohexylamine, hexamethyleneimine, heptamethyleneimine, pyridine, hexahydropyridine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine, or octadecylamine.

[0048] According to a preferred embodiment of the present invention, in step (2), the conditions for hydrothermal crystallization include: a hydrothermal crystallization temperature of 100-200℃, preferably 120-190℃; and a hydrothermal crystallization time of 5-200h, preferably 30-120h. Under the above preferred embodiment, it is beneficial to the nucleation and crystallization of zeolite.

[0049] According to the present invention, the filtration and drying in step (2) can be carried out using conventional techniques in the art, and the present invention does not have any particular limitations on this. Preferably, the drying temperature is 100-200°C, and the drying time is 10-48 hours.

[0050] According to a preferred embodiment of the present invention, in step (4), the weight ratio of the organosilicon zeolite to the binder and / or binder precursor is (5-9):(1-5), more preferably (6-8):(2-3). In the above preferred embodiment, this helps ensure that the catalyst strength is suitable for the requirements of a fixed-bed reaction; preferably, the catalyst strength is greater than 50 N / cm, which is more beneficial for industrial production.

[0051] According to the present invention, the range of choices for the binder is relatively wide, and it can be a conventional choice in the art. Preferably, the binder is selected from at least one of alumina, silica, kaolin, bentonite, montmorillonite, and sepiolite, and more preferably alumina. The binder precursor can be any substance that can be obtained by calcination, and will not be described in detail here.

[0052] According to the present invention, the molding in step (2) can be carried out by conventional technical means in the art, and the present invention does not have any particular limitation. Preferably, the molding is extrusion molding.

[0053] According to a preferred embodiment of the present invention, the drying conditions in step (2) include: a temperature of 100-200°C and a time of 10-48h.

[0054] According to a preferred embodiment of the present invention, the calcination conditions include: a calcination temperature of 400-700℃ and a calcination time of 1-48h; preferably, the calcination temperature is 500-600℃ and the calcination time is 6-36h. Excessively high calcination temperatures may damage the layered structure of the catalyst; excessively low calcination temperatures make it difficult to remove residual template agents. The above-mentioned preferred calcination conditions help to increase the pore volume of the catalyst and further improve its catalytic performance.

[0055] The second aspect of the present invention provides an organosilicon zeolite catalyst prepared by the above preparation method.

[0056] According to a preferred embodiment of the present invention, the organosilicon zeolite catalyst is an H-type organosilicon zeolite catalyst, and preferably, the alkali metal content in the organosilicon zeolite catalyst does not exceed 0.1 wt%. It is understood that when the alkali metal content in the H-type organosilicon zeolite does not exceed 0.1 wt%, the alkali metal content in the organosilicon zeolite catalyst will certainly not exceed 0.1 wt%.

[0057] In this invention, preferably, the organosilicon zeolite catalyst comprises organosilicon zeolite and a binder.

[0058] According to a preferred embodiment of the present invention, the pore volume of the organosilicon zeolite is 0.09-0.7 mL / g, preferably 0.1-0.5 mL / g, and more preferably 0.4-0.5 mL / g. Under these preferred conditions, it is beneficial to improve the catalytic performance of the catalyst.

[0059] In this invention, the pore volume of the organosilicon zeolite is measured by the BET method.

[0060] The third aspect of the present invention provides a method for preparing heavy alkylbenzene, wherein a straight-chain alkylbenzene is contacted with a straight-chain olefin in the presence of a catalyst to carry out an alkylation reaction to obtain heavy alkylbenzene;

[0061] The catalyst is the organosilicon zeolite catalyst mentioned above.

[0062] According to the present invention, the raw materials used in the preparation method of the heavy alkylbenzene are straight-chain alkylbenzenes and straight-chain olefins. The straight-chain alkylbenzenes can be obtained from the alkylation of straight-chain olefins with benzene or directly purchased from alkylbenzene plants. The straight-chain olefins can be obtained from the dehydrogenation of straight-chain alkanes or from Fischer-Tropsch reaction products. Compared with the prior art, the raw materials used in the present invention are more readily available, and the production process has less environmental impact, higher product selectivity, higher product linearity, and a simpler process flow, making it environmentally friendly. The use of the organosilicon zeolite catalyst in the reaction results in a longer catalytic lifetime.

[0063] According to the present invention, the organosilicon zeolite catalyst does not corrode equipment, and the alkylation reaction can be carried out in a conventional reactor. Preferably, the alkylation reaction is carried out in a fixed-bed reactor. Preferably, the method for preparing the heavy alkylbenzene includes: first mixing a straight-chain alkylbenzene raw material with a straight-chain olefin to form a mixture; then feeding the mixture into a fixed-bed reactor; and carrying out an alkylation reaction under the action of the organosilicon zeolite catalyst. After the reaction is completed, the unreacted phenyl raw material is separated to obtain the heavy alkylbenzene. Preferably, the heavy alkylbenzene is C14-C14. 26 -C 32 Alkylbenzene.

[0064] In this invention, the straight-chain alkylbenzene refers to the alkylbenzene generated after the reaction of a straight-chain olefin with benzene; preferably, the straight-chain alkylbenzene is C14-24-3 ... 14 -C 20 The linear alkylbenzene; the linear olefin refers to a linear olefin with 8 or more carbon atoms, preferably C9-C6. 14 Straight-chain olefins. In the preferred embodiments described above, it is advantageous to prepare heavy alkylbenzenes with a suitable number of carbon atoms.

[0065] According to a preferred embodiment of the present invention, the molar ratio of the linear alkylbenzene to the linear olefin is 5-25:1, preferably 8-20:1. This preferred embodiment is beneficial for the long-term stability of the catalyst.

[0066] According to a preferred embodiment of the present invention, the conditions for the alkylation reaction include: a reaction temperature of 120-300°C, a reaction pressure of 1-5 MPa, and a mass hourly space velocity (HHSV) of 0.1-2 h⁻¹ for the straight-chain olefin. -1 Preferably, the reaction temperature is 150-230℃, the reaction pressure is 1-2 MPa, and the mass hourly space velocity (WHSV) of the straight-chain olefin is 0.1-0.5 h⁻¹. -1 If the reaction temperature is too low, the conversion rate will be low, requiring the separation and recycling of raw materials, which increases investment and operating costs; if the reaction temperature is too high, additional cracking will occur, the catalyst coking rate will be accelerated, the catalyst single-pass life will be shortened, and regeneration will be frequent.

[0067] According to a preferred embodiment of the present invention, the method further includes: regenerating the catalyst after the reaction.

[0068] In this invention, the catalyst after reaction corresponds to the fresh catalyst and refers to the catalyst after a period of reaction. It can be a completely deactivated catalyst, a partially deactivated catalyst, or a catalyst with deteriorated performance. The specific definition and selection can be made according to actual production needs.

[0069] According to the present invention, during the production process, catalyst coking should be minimized. Preferably, when the catalyst is partially deactivated, its activity can be restored by in-situ regeneration. More preferably, the catalyst is regenerated after the reaction has been carried out for 100-2000 hours.

[0070] According to a preferred embodiment of the present invention, the regeneration includes: in-situ regeneration of the catalyst in the presence of a linear alkylbenzene. During the regeneration process, there is no need to disassemble the equipment, introduce other materials, or perform material return procedures, making the method simple.

[0071] According to a preferred embodiment of the present invention, the in-situ regeneration temperature is 20-50°C higher than the alkylation reaction temperature; preferably, the conditions for the in-situ regeneration include: a temperature of 140-350°C, a reaction pressure of 1-5 MPa, a time of 10-100 h, and a mass hourly space velocity (WHSV) of 3-20 h⁻¹ for the linear alkylbenzene. -1 Further preferably, the in-situ regeneration conditions include: a temperature of 210-300℃, a reaction pressure of 1-2 MPa, a time of 10-40 h, and a mass hourly space velocity (WHSV) of 5-10 h⁻¹ for the linear alkylbenzene. -1The preferred embodiments described above are beneficial for improving the activity of the regenerated catalyst and the selectivity of heavy alkylbenzenes.

[0072] According to a particularly preferred embodiment of the present invention, a linear alkylbenzene is contacted with a linear olefin in the presence of an organosilicon zeolite catalyst to carry out an alkylation reaction to obtain a heavy alkylbenzene; the molar ratio of the linear alkylbenzene to the linear olefin is 5-25:1; the reaction temperature is 120-300°C, the reaction pressure is 1-5 MPa, and the mass hourly space velocity of the linear olefin is 0.1-2 h⁻¹. -1 Then, in the presence of linear alkylbenzenes, the organosilicon zeolite catalyst after 100-2000 h of reaction is regenerated in situ. The conditions for in-situ regeneration include: 210-300 °C, 10-40 h, and a mass hourly space velocity (WHSV) of 5-10 h⁻¹ for the linear alkylbenzenes. -1 The organosilicon zeolite catalyst is prepared by the following method:

[0073] (1) Mix silicon source, aluminum source, alkali source, template agent and water to obtain a mixture; wherein the molar ratio of silicon source, aluminum source, alkali source, template agent and water is 10:(0.2-2):(5-30):(0.6-10):(20-300), silicon source is calculated as SiO2, aluminum source is calculated as Al2O3, and alkali source is calculated as OH. - The silicon source includes an organosilicon source and an inorganic silicon source, and the molar ratio of the organosilicon source to the inorganic silicon source is 0.005-0.2:1.

[0074] (2) The mixture is subjected to hydrothermal crystallization, filtered and dried to obtain a solid product; the temperature of hydrothermal crystallization is 120-190℃ and the time of hydrothermal crystallization is 30-120h.

[0075] (3) In the presence of a solvent, the solid product is modified with a cation exchange resin to obtain H-type organosilicon zeolite, wherein the alkali metal content in the H-type organosilicon zeolite does not exceed 0.1 wt%; the exchange conditions include: a reaction temperature of 60-80℃ and a reaction time of 0.5-1h.

[0076] (4) The H-type organosilicon zeolite is mixed with a binder and / or a binder precursor, molded, dried, and calcined to obtain the organosilicon zeolite catalyst. The calcination temperature is 500-600℃, and the calcination time is 6-36h.

[0077] The present invention will be described in detail below through embodiments.

[0078] In the following examples, the linear alkylbenzene and linear olefin raw materials are commercially available products from Nanjing Alkylbenzene Plant.

[0079] The following examples illustrate the preparation of organosilicon zeolite catalysts.

[0080] Example 1

[0081] (1) A mixture of silicon source, sodium aluminate, sodium hydroxide, hexamethyleneimine, and water at a molar ratio of 10:0.7:16:2:100 was obtained at 10°C. The silicon source was calculated as SiO2, the aluminum source as Al2O3, and the alkali source as OH. - The silicon source includes trimethylethoxysilane and silica sol. The molar ratio of trimethylethoxysilane to silica sol is 0.1:1, calculated based on elemental silicon.

[0082] (2) The mixture was hydrothermally crystallized at 160°C for 30 h, filtered, and dried at 120°C for 24 h to obtain a solid product;

[0083] (3) 10g of the above solid product was impregnated in an aqueous solution containing 20g of a strong acid styrene-based cation exchange resin (model D001, commercially available, with an exchange capacity ≥1.8mmol / g) for modification treatment. The mass ratio of water to cation exchange resin was 2:1, and the total acidity of the cation exchange resin relative to 1g of the solid product was 3.6mmol. Ion exchange was performed at 20℃ for 1h, followed by filtration, washing, and drying at 130℃ for 20h to obtain H-type organosilicon zeolite. The alkali metal content was tested by ICP, and the results of the alkali metal content and pore volume of H-type organosilicon zeolite are shown in Table 1.

[0084] The H-type organosilicon zeolite was mixed with alumina and shaped into a product with a mass ratio of 7:3. After drying at 150°C for 20 hours, the product was calcined at 550°C for 24 hours to obtain the organosilicon zeolite catalyst A1.

[0085] Example 2

[0086] (1) A mixture of silicon source, alumina, sodium hydroxide, ethylenediamine, and water was prepared at 5°C in a molar ratio of 10:0.65:17:2:150 to obtain a mixture, wherein the silicon source was calculated as SiO2, the aluminum source as Al2O3, and the alkali source as OH. - The silicon source includes dimethyldiethoxysilane and silica sol. The molar ratio of dimethyldiethoxysilane to silica sol is 0.05:1, calculated based on elemental silicon.

[0087] (2) The mixture was hydrothermally crystallized at 140°C for 40 h, filtered, and dried at 150°C for 20 h to obtain a solid product;

[0088] (3) 10g of the above solid product was impregnated in an aqueous solution containing 15g of a strong acid acrylic cation exchange resin (model 011, with a total volume exchange capacity of ≥1.5mmol / g, commercially available) in a total volume of 40g. The mass ratio of water to cation exchange resin was 2.7:1, and the total acidity of the cation exchange resin relative to 1g of the solid product was 2.25mmol. The treatment was carried out at 40℃ for 1.5h, followed by filtration, washing, and drying at 130℃ for 20h to obtain H-type organosilicon zeolite. The alkali metal content was tested by ICP, and the alkali metal content and pore volume of H-type organosilicon zeolite are shown in Table 1.

[0089] The H-type organosilicon zeolite was mixed with alumina and shaped into a product with a mass ratio of 6:4. After drying at 120°C for 24 hours, the product was calcined at 500°C for 28 hours to obtain the organosilicon zeolite catalyst A2.

[0090] Example 3

[0091] (1) A mixture of silicon source, alumina, sodium hydroxide, hexadecylamine, and water at a molar ratio of 10:0.68:16:2:120 was obtained at 15°C. The silicon source was calculated as SiO2, the aluminum source as Al2O3, and the alkali source as OH. - The silicon source includes dimethyldichlorosilane and water glass. The molar ratio of dimethyldichlorosilane to water glass is 0.008:1, calculated based on silicon element.

[0092] (2) The mixture was hydrothermally crystallized at 130°C for 50 h, filtered, and dried at 100°C for 36 h to obtain a solid product;

[0093] (3) 10g of the above solid product was impregnated in a solution containing 40g of 25g of a strongly acidic styrene-based cation exchange resin (model D001, with a total volumetric exchange capacity of ≥1.8mmol / g, commercially available) for modification treatment. The mass ratio of water to cation exchange resin was 1.6:1, and the total acidity of the cation exchange resin relative to 1g of the solid product was 4.5mmol. Ion exchange was performed at 70℃ for 1h, followed by filtration, washing, and drying at 130℃ for 20h to obtain H-type organosilicon zeolite. The alkali metal content was tested by ICP, and the alkali metal content and pore volume of H-type organosilicon zeolite are shown in Table 1.

[0094] The H-type organosilicon zeolite was mixed with alumina and shaped into a product with a mass ratio of 6.5:3.5. After drying at 150°C for 24 hours, the product was calcined at 540°C for 24 hours to obtain organosilicon zeolite catalyst A3.

[0095] Example 4

[0096] The method was followed in Example 1, except that the modification conditions were: reaction temperature of 100°C and reaction time of 1 hour. The alkali metal content and pore volume of the H-type organosilicon zeolite are shown in Table 1, and the obtained organosilicon zeolite catalyst is designated as A4.

[0097] Example 5

[0098] The method of Example 1 was followed, except that the molar ratio of trimethylethoxysilane to silica sol was 0.001:1 based on silicon element. The alkali metal content and pore volume of the H-type organosilicon zeolite are shown in Table 1. The obtained organosilicon zeolite catalyst is denoted as A5.

[0099] Example 6

[0100] The method of Example 1 was followed, except that the catalyst calcination temperature was 400°C. The alkali metal content and pore volume of the H-type organosilicon zeolite are shown in Table 1. The obtained organosilicon zeolite catalyst is denoted as A6.

[0101] Comparative Example 1

[0102] The method of Example 1 is different except that no modification treatment is performed. The solid product obtained in step (2) is organosilicon zeolite. The alkali metal content and pore volume results are shown in Table 1. The obtained organosilicon zeolite catalyst is denoted as DA1.

[0103] Comparative Example 2

[0104] The method was followed in Example 1, except that the mass of the strongly acidic styrene-based cation exchange resin was 3 g, the mass ratio of water to cation exchange resin was 13.3:1, and the total acidity of the cation exchange resin was 0.54 mmol relative to 1 g of the solid product. The alkali metal content and pore volume of the H-type organosilicon zeolite are shown in Table 1, and the obtained organosilicon zeolite catalyst is designated as DA2.

[0105] Table 1

[0106]

[0107] The following test examples illustrate the preparation method of heavy alkylbenzenes.

[0108] The catalyst single-pass usage time refers to the reaction time experienced when the conversion rate of olefins in the feedstock decreases to 70% of the initial conversion rate.

[0109] Test Example 1

[0110] Take 5g of the above organosilicon zeolite catalyst A1 in a fixed-bed reactor, and add linear alkylbenzene (C 14 -C 20 ) and straight-chain olefins (C9-C) prepared by alkane dehydrogenation 14The feedstock was prepared by mixing the ingredients at a molar ratio of 10:1, and the composition of the feedstock is shown in Table 2. The reaction was carried out at a temperature of 190℃, a pressure of 2 MPa, and a linear olefin mass hourly space velocity of 0.2 h⁻¹. -1 The reaction was carried out under specific conditions, and the product was analyzed by chromatography. The reaction results and the single-pass usage time of the catalyst are shown in Table 3.

[0111] Catalyst regeneration was carried out after 500 hours of reaction. During regeneration, the linear olefin feed was stopped, and the reaction was conducted at 235°C, 2 MPa, and a linear alkylbenzene mass hourly space velocity (WHSV) of 5 h⁻¹. -1 Regeneration was carried out under the specified conditions for 24 hours, which was considered as completing one regeneration process. The temperature was then lowered to 190℃ and the pressure to 2 MPa, and straight-chain olefins were introduced again. The above reaction and regeneration process were repeated, and the olefin conversion rate after each regeneration was calculated. The stability was also examined, and the results are shown in Table 4.

[0112] Test Example 2-6

[0113] Following the method of Test Example 1, except that the organosilicon zeolite catalysts were replaced with A2-A6 respectively, the products were analyzed by chromatography, and the reaction results and the single-pass usage time of the catalysts are shown in Table 3.

[0114] Test Example 7

[0115] The method was the same as in Test Example 1, except that the reaction temperature was 160℃, the pressure was 2.0 MPa, and the mass hourly space velocity (HHSV) of the straight-chain olefin was 1.0 h⁻¹. -1 The product was analyzed by chromatography, and the reaction results and the single-pass usage time of the catalyst are shown in Table 3.

[0116] Test Example 8

[0117] Following the method of Test Example 1, the difference is that linear alkylbenzenes (C... 14 -C 20 ) and straight-chain olefins (C9-C) prepared by alkane dehydrogenation 14 The raw materials were mixed at a molar ratio of 3:1. The product was analyzed by chromatography, and the reaction results and the single-pass usage time of the catalyst are shown in Table 3.

[0118] Comparative Test Cases 1-2

[0119] The method was the same as in Test Example 1, except that the organosilicon zeolite catalyst was replaced with DA1 and DA2. The product was analyzed by chromatography, and the reaction results and the single-pass usage time of the catalyst are shown in Table 3.

[0120] Table 2 Raw Material Composition

[0121] linear alkylbenzene C14 3％ C15 9％ C16 18％ C17 24％ C18 25％ C19 16％ C20 5％ straight-chain olefins C9 10％ C10 19％ C11 24％ C12 25％ C13 16％ C14 6％

[0122] Table 3

[0123]

[0124]

[0125] Table 4

[0126] Olefin conversion 99.8％ 99.8％ 99.7％ 99.7％ 99.6％ 99.6％ heavy alkylbenzene selectivity 99.9％ 99.6％ 99.2％ 98.9％ 98.6％ 98.4％

[0127] Based on the results in Tables 1 and 3, and through test examples 1-7 and comparative test examples 1-2, it can be seen that the catalyst provided by this invention, combined with specific reaction conditions and raw material ratios, exhibits significantly better performance in the preparation of heavy alkylbenzene.

[0128] Examples 1-5 show that the organosilicon zeolite catalyst prepared by the method of this invention can be modified with cation exchange resin to obtain H-type organosilicon zeolite in one step. The alkali metal content in the H-type organosilicon zeolite is less than 0.1 wt%, avoiding the subsequent ammonium exchange process, increasing catalyst activity, increasing olefin conversion rate, and increasing heavy alkylbenzene selectivity. A comparison of Examples 1 and 5 shows that introducing an appropriate amount of organosilicon source during the preparation of the organosilicon zeolite catalyst helps to further improve the catalyst's catalytic performance. Examples 1 and 6 show that if the catalyst forming temperature is too low, the template agent introduced during the preparation of the zeolite molecular sieve may be difficult to remove completely, resulting in incomplete exposure of the active centers of the catalyst and thus poor catalytic effect.

[0129] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing heavy alkylbenzene, characterized in that, In the presence of a catalyst, straight-chain alkylbenzene is contacted with a straight-chain olefin to carry out an alkylation reaction to obtain a heavy alkylbenzene; the method further includes: in-situ regeneration of the catalyst in the presence of straight-chain alkylbenzene; The catalyst is an organosilicon zeolite catalyst prepared by the following method; Includes the following steps: (1) A mixture is prepared by mixing a silicon source, an aluminum source, an alkali source, a template agent and water; wherein the silicon source includes an organosilicon source and an inorganic silicon source; The molar ratio of silicon source, aluminum source, alkali source, template agent, and water is 10:(0.6-0.9):(14-18):(1-3):(40-200), where the silicon source is calculated as SiO2, the aluminum source as Al2O3, and the alkali source as OH-. - The molar ratio of the organic silicon source to the inorganic silicon source, calculated as elemental silicon, is 0.008-0.1:

1. (2) The mixture is subjected to hydrothermal crystallization, filtered and dried to obtain a solid product; (3) In the presence of a solvent, the solid product is modified with a cation exchange resin to obtain H-type organosilicon zeolite, wherein the alkali metal content in the H-type organosilicon zeolite is not more than 0.1% by weight; the cation exchange resin is a strong acid styrene-based cation exchange resin and / or a strong acid acrylic-based cation exchange resin, and the amount of cation exchange resin used relative to 1g of the solid product is such that the total acid content of the cation exchange resin is not less than 1mmol; (4) The H-type organosilicon zeolite is mixed with a binder and / or a binder precursor, and then dried and calcined to obtain the organosilicon zeolite catalyst.

2. The method for preparing heavy alkylbenzene according to claim 1, wherein, The conditions for the modification treatment include: a reaction temperature of 10-90℃ and a reaction time of 0.5-4h.

3. The method for preparing heavy alkylbenzene according to claim 2, wherein, The conditions for the modification treatment include: a reaction temperature of 10-40℃ and a reaction time of 0.5-1h.

4. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The solvent is water.

5. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, In the modification treatment, the mass ratio of the solvent to the cation exchange resin is 1-20:

1.

6. The method for preparing heavy alkylbenzene according to claim 5, wherein, In the modification treatment, the mass ratio of the solvent to the cation exchange resin is 1.5-5:

1.

7. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The amount of cation exchange resin used relative to 1g of the solid product is such that the total acid content of the cation exchange resin is not less than 2mmol.

8. The method for preparing heavy alkylbenzene according to claim 1, wherein, The mixing temperature in step (1) is 0-40℃.

9. The method for preparing heavy alkylbenzene according to claim 8, wherein, The mixing temperature in step (1) is 4-15℃.

10. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The organosilicon source is selected from at least one of halosilanes, silazanes, and alkoxysilanes; The inorganic silicon source is selected from at least one of solid silicon oxide, silicate ester, silica sol, and water glass.

11. The method for preparing heavy alkylbenzene according to claim 10, wherein, The halosilane is selected from at least one of trimethylchlorosilane, dimethyldichlorosilane, triethylchlorosilane, diethyldichlorosilane, dimethylchlorobromosilane, and dimethylethylchlorosilane; Alternatively, the silazane is selected from at least one of hexamethyldisilazane, heptamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, and diphenyltetramethyldisilazane; Alternatively, the alkoxysilane is selected from at least one of trimethylethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, dimethyldimethoxysilane, and trimethoxyphenylsilane.

12. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The aluminum source is selected from at least one of metallic aluminate, metallic aluminate, aluminum powder, kaolin, montmorillonite, and alumina.

13. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The alkali source is an inorganic alkali.

14. The method for preparing heavy alkylbenzene according to claim 13, wherein, The alkali source is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and calcium hydroxide.

15. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The template agent is an organic amine template agent.

16. The method for preparing heavy alkylbenzene according to claim 15, wherein, The template agent is selected from at least one of ethylenediamine, hexamethylenediamine, cyclohexylamine, hexamethyleneimine, heptamethyleneimine, pyridine, hexahydropyridine, butylamine, hexamine, octylamine, decylamine, dodecylamine, hexadecylamine, and octadecylamine.

17. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, In step (2), the conditions for hydrothermal crystallization include: the temperature of hydrothermal crystallization is 100-200℃ and the time of hydrothermal crystallization is 5-200h.

18. The method for preparing heavy alkylbenzene according to claim 17, wherein, In step (2), the conditions for hydrothermal crystallization include: the temperature of hydrothermal crystallization is 120-160℃; and the time of hydrothermal crystallization is 30-120h.

19. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, In step (4), the weight ratio of the organosilicon zeolite to the binder and / or binder precursor is (5-9):(1-5).

20. The method for preparing heavy alkylbenzene according to claim 19, wherein, In step (4), the weight ratio of the organosilicon zeolite to the binder and / or binder precursor is (6-8):(2-3).

21. The method for preparing heavy alkylbenzene according to any one of claims 1-3, wherein, The binder is selected from at least one of alumina, silica, kaolin, bentonite, montmorillonite, and sepiolite.

22. The method for preparing heavy alkylbenzene according to claim 21, wherein, The adhesive is aluminum oxide.

23. The method for preparing heavy alkylbenzene according to claim 1, wherein, The alkali metal content in the organosilicon zeolite catalyst does not exceed 0.1% by weight.

24. The method for preparing heavy alkylbenzene according to claim 1, wherein, The organosilicon zeolite catalyst comprises organosilicon zeolite and a binder.

25. The method for preparing heavy alkylbenzene according to claim 1, wherein, In the organosilicon zeolite catalyst, the pore volume of the organosilicon zeolite is 0.1-0.5 mL / g.

26. The method for preparing heavy alkylbenzene according to claim 1, wherein, The straight-chain alkylbenzene is C 14 -C 20 A straight-chain alkylbenzene, wherein the straight-chain olefin is C9-C6. 14 Straight-chain olefins.

27. The method for preparing heavy alkylbenzene according to claim 1, wherein, The molar ratio of the linear alkylbenzene to the linear olefin is 5-25:

1.

28. The method for preparing heavy alkylbenzene according to claim 27, wherein, The molar ratio of the linear alkylbenzene to the linear olefin is 8-20:

1.

29. The method for preparing heavy alkylbenzene according to claim 1, wherein, The alkylation reaction conditions include: a reaction temperature of 120-300℃, a reaction pressure of 1-5 MPa, and a mass hourly space velocity (HHSV) of 0.1-2 h⁻¹ for the straight-chain olefin. -1 .

30. The method for preparing heavy alkylbenzene according to claim 29, wherein, The alkylation reaction conditions include: a reaction temperature of 150-230℃, a reaction pressure of 1-2 MPa, and a mass hourly space velocity (HHSV) of 0.1-0.5 h⁻¹ for the straight-chain olefin. -1 .

31. The method for preparing heavy alkylbenzene according to claim 1, wherein, The conditions for in-situ regeneration include: a temperature of 140-350℃, a time of 10-100 h, and a mass hourly space velocity (MSV) of 3-20 h⁻¹ for linear alkylbenzenes. -1 .

32. The method for preparing heavy alkylbenzene according to claim 31, wherein, The conditions for in-situ regeneration include: a temperature of 210-300℃, a time of 10-40 h, and a mass hourly space velocity (MSV) of 5-10 h⁻¹ for linear alkylbenzenes. -1 .

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