A process for the preparation of cumene and the cumene obtained thereby

Abstract

The application discloses a method for preparing cumene and the cumene obtained by using the method, and the method comprises the following steps: (1) reacting cumene peroxide-containing material with propylene, and separating the reaction product to obtain propylene oxide-containing material and alpha,alpha-dimethyl benzyl alcohol-containing material; (2) performing conversion treatment on the alpha,alpha-dimethyl benzyl alcohol-containing material to obtain cumene material; wherein, the alpha,alpha-dimethyl benzyl alcohol-containing material is treated after step (1) and before step (2), and the total content of titanium element, silicon element and aluminum element in the alpha,alpha-dimethyl benzyl alcohol-containing material is controlled to be less than or equal to 1 ppm. By strictly controlling the titanium element, silicon element and aluminum element in the raw material entering the DMBA conversion process, the DMBA conversion rate can be ensured not to be obviously reduced under long-time operation without affecting the DMBA conversion activity.

Description

TECHNICAL FIELD

[0001] The present application relates to the preparation of cumene, in particular to the preparation of cumene in the process of preparing propylene oxide by cumene hydroperoxide (CHP) method. BACKGROUND

[0002] Propylene oxide (PO) is an important organic chemical product as a downstream product of propylene, which can be used to produce polyether polyols, the precursors of polyurethane materials. The CHP method for preparing PO developed by Sumitomo Chemical Company of Japan has no by-products and is environmentally friendly and clean, and has low investment. The CHP method for preparing PO includes the processes of cumene oxidation, propylene epoxidation and DMBA hydrogenolysis.

[0003] In the propylene oxidation unit, titanium-silicon type catalysts are mostly used. For example, patent CN1500004 discloses a catalyst similar to Ti / MCM-41 for preparing PO by epoxidizing propylene. Similarly, patents CN105367520A and CN104437618A also disclose titanium-silicon catalysts for the process of epoxidizing propylene. However, in the process of preparing PO by selective oxidation of propylene by CHP, side reactions inevitably occur to generate acidic substances such as formic acid, acetic acid and phenol. The acidic substances can easily cause the loss of titanium and silicon elements in the titanium-silicon catalyst, which not only causes the deactivation of the epoxidation catalyst, but also causes the enrichment of the lost titanium and silicon elements on the DMBA hydrogenolysis catalyst in the downstream process, thereby causing 1) the deactivation of the DMBA hydrogenolysis catalyst and 2) the increase of the bed pressure drop.

[0004] In the process of preparing cumene by DMBA hydrogenolysis, the existing technology pays more attention to the modification of the catalyst to improve the activity and selectivity of the hydrogenolysis of α,α-dimethylbenzyl alcohol and the process technology, and less attention to the technical problems of how to realize stable operation of the device in the design and development of the hydrogenolysis process. SUMMARY

[0005] In order to overcome the problems in the prior art, the present application provides a method for preparing cumene and the obtained cumene, which improves the stability of the catalyst in the hydrogenolysis of α,α-dimethylbenzyl alcohol (DMBA) by controlling the total content of titanium elements, silicon elements and aluminum elements in the α,α-dimethylbenzyl alcohol (DMBA) raw material without changing the catalyst, so as to ensure that the conversion rate of α,α-dimethylbenzyl alcohol (DMBA) does not decrease significantly during long-term operation.

[0006] One of the purposes of the present application is to provide a method for preparing cumene, which comprises:

[0007] (1) The material containing cumene peroxide reacts with propylene, and the reaction products are separated to obtain the material containing propylene oxide and the material containing α,α-dimethylbenzyl alcohol, respectively.

[0008] (2) The material containing α,α-dimethylbenzyl alcohol is converted to obtain cumene material;

[0009] The material containing α,α-dimethylbenzyl alcohol is processed after step (1) and before step (2) to control the total content of titanium, silicon and aluminum in the material to be less than 1 ppm (preferably not including 1 ppm).

[0010] For example, the total content of titanium, silicon and aluminum in the material is controlled to be 0 ppm, 0.1 ppm, 0.2 ppm, 0.3 ppm, 0.4 ppm, 0.5 ppm, 0.6 ppm, 0.7 ppm, 0.8 ppm, 0.9 ppm or 0.95 ppm.

[0011] Step (1) of this invention is the reaction process of CHP oxidizing propylene to PO, using a silicon-titanium catalyst (e.g., silicon-titanium molecular sieve) as the catalyst. In this reaction process, side reactions are unavoidable, generating acidic substances such as formic acid, acetic acid, and phenol. Acidic substances can easily cause the loss of titanium, silicon and other elements in the titanium-silicon catalyst used in this reaction process. Thus, (A) it will not only cause the epoxidation catalyst to be deactivated, but also cause the lost titanium, silicon and other elements to be carried downstream with the materials, such as the α,α-dimethylbenzyl alcohol conversion process in step (2); (B) the lost titanium, silicon and other elements will be enriched on the benzyl alcohol conversion catalyst in step (2) (the catalyst surface removed by the inventors has a lot of powder enrichment, and after analysis, it was found to contain titanium, or at least one of silicon and aluminum, especially titanium). Over time, this will cause the deactivation of the benzyl alcohol conversion catalyst in step (2) and the increase of the bed pressure drop in step (2), and even blockage of the reaction tube, affecting the conversion rate of benzyl alcohol under long-term operation.

[0012] In a preferred embodiment, the total content of titanium, silicon and aluminum in the material containing α,α-dimethylbenzyl alcohol in step (2) is controlled to be less than 0.6 ppm.

[0013] In a further preferred embodiment, the total content of titanium, silicon and aluminum in the material containing α,α-dimethylbenzyl alcohol in step (2) is less than 0.3 ppm, preferably less than 0.1 ppm.

[0014] In the α,α-dimethylbenzyl alcohol hydrogenolysis (DMBA) process, the titanium, silicon, and aluminum elements in the material are mainly due to the loss of titanium, silicon, and aluminum elements from the titanium-silicon catalyst and / or alumina catalyst in step (1). Through extensive experimental research, the inventors discovered that the total content of titanium, silicon, and aluminum elements (especially titanium) in the material entering the hydrogenolysis unit should be controlled below 1 ppm (preferably below 0.3 ppm, more preferably below 0.1 ppm). Otherwise, they will accumulate on the catalyst used in step (2), such as the hydrogenolysis catalyst, causing degradation of the catalyst, a decrease in catalyst activity and lifespan, and affecting the stable operation of the device. This is because elements such as titanium accumulate on the catalyst (e.g., alumina dehydration catalyst and / or metal-based catalysts such as Pd / Cu / Ni), covering active sites and causing a decrease in catalyst performance.

[0015] For example, when the epoxidation catalyst in step (1) is a titanium-silicon catalyst, the resulting material containing α,α-dimethylbenzyl alcohol may contain titanium and / or silicon; and the resulting material containing α,α-dimethylbenzyl alcohol may contain aluminum.

[0016] In a preferred embodiment, in step (1), the reaction temperature is controlled at 25-200°C and the reaction pressure is controlled at 0.1-10 MPa.

[0017] In a further preferred embodiment, in step (1), the reaction temperature is controlled at 50 to 150°C and the reaction pressure is controlled at 0.4 to 8 MPa.

[0018] For example, in step (1), the reaction temperature is controlled at 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 120℃, 140℃, 160℃, 180℃ or 200℃, and the reaction pressure is controlled at 0.1-10 MPa.

[0019] In a preferred embodiment, in step (1), the molar ratio of propylene to cumene peroxide is controlled to be (2-30):1, preferably (4-20):1, and more preferably (6-15):1.

[0020] For example, in step (1), the molar ratio of propylene to cumene peroxide is controlled to be 2:1, 5:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 28:1 or 30:1.

[0021] Step (1) can be carried out in the form of a slurry bed or a fixed bed. Considering industrial applications, the fixed bed form is preferred.

[0022] In a preferred embodiment, step (1) is carried out in the presence of a solid catalyst, the solid catalyst comprising a support and an active component supported on the support, preferably, the support being selected from silicon oxide and / or aluminum oxide, and the active component being titanium.

[0023] In a further preferred embodiment, the solid catalyst is selected from at least one of titanium-containing silicon oxide, titanium-containing aluminum oxide, and titanium-containing silicon-aluminum oxide; preferably, the titanium-containing silicon oxide can be a titanium-containing porous silica catalyst, more preferably, the titanium-containing porous silica catalyst is selected from at least one of titanium-containing mesoporous silica catalysts (such as Ti-HMS, Ti-MCM-41), titanium-containing macroporous silica catalysts (Ti-SiO2), and titanium-containing composite porous silica catalysts.

[0024] The titanium-containing aluminum oxide mainly refers to a catalyst supported on alumina and loaded with titanium; the titanium-containing silicon-alumina oxide can be a catalyst supported on alumina-silica and loaded with titanium, or a catalyst supported on silica, with alumina as a binder or other additives and loaded with titanium, or a catalyst supported on alumina, with silica as a binder or other additives and loaded with titanium.

[0025] In a further preferred embodiment, the weight content of titanium in the titanium-containing silicon oxide, titanium-containing aluminum oxide, and titanium-containing silicon-aluminum oxide is independently 0.05%-10%, preferably 0.1%-5.0%; and / or, the weight content of titanium in the titanium-containing aluminum oxide is 0.05%-10%, preferably 0.1%-5.0%.

[0026] For example, the weight content of titanium in the titanium-containing silicon oxide, titanium-containing aluminum oxide, and titanium-containing silicon-aluminum oxide is independently 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0027] The titanium-containing silicon oxides and titanium-containing aluminum oxides mentioned above can all be produced using existing titanium-containing silicon dioxide catalysts and titanium-containing aluminum oxide catalysts.

[0028] In step (1), the epoxidation reaction is carried out by contacting propylene and cumene peroxide with a catalyst, and the reaction can be carried out in a liquid phase using a solvent. The solvent used in the epoxidation reaction must be liquid within the reaction temperature and pressure range, and must be substantially inert relative to the reactants and products, preferably cumene.

[0029] In a preferred embodiment, in step (1), the reactants are distilled to obtain propylene oxide-containing material and α,α-dimethylbenzyl alcohol-containing material, respectively.

[0030] In step (1), the process of distilling and separating propylene oxide and α,α-dimethylbenzyl alcohol can be carried out using existing technologies.

[0031] In a preferred embodiment, the conversion process in step (2) is carried out as follows: first dehydration followed by hydrogenation, or direct hydrogenolysis; preferably direct hydrogenolysis.

[0032] In a preferred embodiment, the dehydration and hydrogenation processes are performed as follows:

[0033] (2.1) Dehydration treatment: In the presence of a catalyst, the material containing α,α-dimethylbenzyl alcohol is subjected to a dehydration reaction to obtain the material containing α-methylstyrene;

[0034] (2.2) Hydrogenation treatment: In the presence of a catalyst, the material containing α-methylstyrene is reacted with hydrogen to obtain cumene material.

[0035] In a further preferred embodiment, the reaction temperature in the dehydration treatment is 50–400°C, preferably 150–250°C; and / or the reaction pressure is 0.1–6 MPa, preferably 0.5–4 MPa, more preferably 1–3 MPa.

[0036] For example, in the dehydration process, the reaction temperature is 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, or 400°C; and / or, the reaction pressure is 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, or 6 MPa.

[0037] In a further preferred embodiment, in the hydrogenation treatment, the molar ratio of hydrogen to α-methylstyrene is (1-15):1, preferably (1-10):1, more preferably (1-5):1; and / or, the reaction temperature is 0-500°C, preferably 30-400°C, more preferably 50-300°C; and / or, the reaction pressure is 0.1-10 MPa, preferably 0.5-4 MPa, more preferably 1-3 MPa.

[0038] For example, in the hydrogenation process, the molar ratio of hydrogen to α-methylstyrene is 1:1, 2:1, 5:1, 8:1, 10:1, 12:1, or 15:1; the reaction temperature is 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, or 400°C; and the reaction pressure is 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa.

[0039] In a preferred embodiment, in the dehydration process, the catalyst is selected from solid acid catalysts, preferably at least one of alumina, amorphous silica-alumina oxide, acidic clay, and zeolite molecular sieve.

[0040] The dehydration reaction is carried out by contacting α,α-dimethylbenzyl alcohol with a catalyst, and the reaction can be conducted in a liquid phase using a solvent. The solvent used in the dehydration reaction must be substantially inert relative to the reactants and products, and is preferably cumene.

[0041] In a preferred embodiment, in the hydrogenation process, the catalyst comprises a support and a metal component supported on the support.

[0042] In a further preferred embodiment, the carrier is selected from at least one of alumina, silicon dioxide, and activated carbon, with alumina being preferred.

[0043] In a further preferred embodiment, the metal component is selected from at least one metal from Group VIII and Group IB, preferably from at least one of nickel, palladium, platinum and copper.

[0044] The hydrogenation reaction is carried out by contacting α-methylstyrene with a hydrogen catalyst, and the reaction can be carried out in a liquid or gas phase environment using a solvent. The solvent used in the dehydration reaction must be substantially inert relative to the reactants and products, and is preferably cumene.

[0045] In this invention, the catalysts for dehydration and hydrogenation are in slurry or fixed-bed form, with a fixed-bed form preferred industrially. The production methods for dehydration and hydrogenation include batch, semi-continuous, and continuous processes. During production, dehydration and hydrogenation can be performed in a single reactor or in separate reactors.

[0046] In a preferred embodiment, the direct hydrogenolysis process is carried out as follows: in the presence of a catalyst, the material containing α,α-dimethylbenzyl alcohol is mixed with hydrogen gas and reacted to obtain cumene material.

[0047] In a further preferred embodiment, in the direct hydrogenolysis treatment, the molar ratio of hydrogen to α,α-dimethylbenzyl alcohol is (2-15):1, preferably (3-9):1; and / or, the reaction temperature is 0-300°C, preferably 40-200°C, more preferably 150-200°C; and / or, the reaction pressure is 0-5 MPa, preferably 0.1-2.0 MPa; and / or, the space velocity of the material containing α,α-dimethylbenzyl alcohol is 0.5-2 h⁻¹. -1 Preferably 0.8-1.5h -1 .

[0048] For example, in the direct hydrogenolysis process, the molar ratio of hydrogen to α,α-dimethylbenzyl alcohol is 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or 15:1; the reaction temperature is 20°C, 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 250°C, or 300°C; the reaction pressure is 0 MPa, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, or 5 MPa; and the space velocity of the material containing α,α-dimethylbenzyl alcohol is 0.5 h⁻¹. -1 0.8h -1 1h -1 1.2h -1 1.5h -1 1.8h -1 or 2h -1 .

[0049] The hydrogenolysis process can be carried out in a liquid or gas phase environment using a solvent. The solvent used in the reaction must be substantially inert relative to the reactants and products, preferably cumene.

[0050] In a preferred embodiment, in the direct hydrogenolysis process, the catalyst may be a hydrogenolysis catalyst disclosed in the prior art, preferably but not limited to the catalyst comprising a support and a metal component supported on the support.

[0051] In a further preferred embodiment, the carrier is selected from at least one of alumina, silicon dioxide, and activated carbon, with alumina being preferred.

[0052] In a further preferred embodiment, the metal component is selected from at least one metal from Group VIII and Group IB, preferably from at least one of nickel, palladium, platinum and copper.

[0053] In a preferred embodiment, the material containing cumene peroxide in step (1) is obtained as follows:

[0054] (1') The material containing cumene is oxidized to obtain the material containing cumene peroxide.

[0055] In a preferred embodiment, in step (1'), the oxidation treatment is carried out at 50–200°C and 0–5 MPa.

[0056] In a further preferred embodiment, in step (1'), the oxidation treatment is carried out at 60–180°C and 0.01–2 MPa.

[0057] For example, in step (1'), the temperature of the oxidation treatment is 50°C, 80°C, 100°C, 150°C or 200°C; the pressure of the oxidation treatment is 0MPa, 1MPa, 2MPa, 3MPa, 4MPa or 5MPa.

[0058] In a preferred embodiment, in step (1'), the oxidation process is carried out under an oxygen-containing gas, preferably air, oxygen, or oxygen-enriched air.

[0059] The oxygen-containing gas is selected from air, oxygen, or oxygen-enriched air, preferably with an oxygen content of 21-50%. The oxidation treatment is carried out in an oxidation reactor, and more preferably, the volume content of O2 in the tail gas of the oxidation reactor is controlled to be no more than 6%.

[0060] In a further preferred embodiment, in step (1'), an alkaline washing treatment is performed during or after the oxidation process.

[0061] In a further preferred embodiment, in step (1'), the oxidation treatment is carried out in an alkaline environment; or, after obtaining the cumene peroxide (CHP) oxidizing solution through oxidation treatment, the alkaline solution is added to the cumene peroxide (CHP) oxidizing solution.

[0062] In a further preferred embodiment, in step (1'), a water wash is performed after the alkaline wash.

[0063] Therefore, oxidation treatment can be carried out directly in an alkaline solution, or it can be performed without adding an alkaline solution, but then adding one after oxidation. During the oxidation step, organic acid byproducts are inevitably generated. After oxidation treatment, an alkaline solution is used to remove the acidic substances (e.g., organic acids). Deacidification removes the organic acids from the cumene peroxide oxidation solution produced during the oxidation step. Organic acids can be removed by washing with an aqueous solution of alkali metal, alkaline earth metal, or ammonia hydroxide or carbonate (generally an aqueous solution of Na₂CO₃ or NaOH). The purpose of water washing after alkaline washing is to remove metal ions (e.g., sodium ions) introduced during alkaline washing.

[0064] In a preferred embodiment, the alkaline solution is selected from an aqueous solution of at least one of alkali metal hydroxides (e.g., NaOH, KOH), alkaline earth metal hydroxides (e.g., Mg(OH)2, Ca(OH)2), alkali metal carbonates, and alkali metal ammonium carbonates.

[0065] While existing technologies can reduce the metal ion content through subsequent water washing, the content will still remain at a high level after washing.

[0066] In a further preferred embodiment, the concentration of the alkaline solution is 1-10 wt%, preferably 2-5 wt%.

[0067] For example, the concentration of the alkaline solution is 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0068] In a further preferred embodiment, when alkali is added during the oxidation process, the ratio of alkali to cumene is controlled to be (3-0.1):1, preferably (1-0.2):1; or, when alkali is added after the oxidation process, the ratio of alkali to cumene peroxide is controlled to be (3-0.1):1, preferably (1-0.2):1.

[0069] In order to control the concentration of metal ions (such as sodium ions) at a low level after water washing, it is necessary to minimize the addition of alkali solution during the oxidation process. After reducing the amount of alkali solution, to achieve the desired washing effect, the washing process is enhanced by increasing agitation and extending contact time to strengthen contact and material exchange.

[0070] In a preferred embodiment, in the water washing step (1'), the volume ratio of water to the oxidizing liquid after alkaline washing is (2-0.1):1, preferably (1.2-0.3):1.

[0071] In a further preferred embodiment, the water washing in step (1') is performed at 25–150°C, preferably at 30–90°C.

[0072] The solution after alkali washing is washed with water, and then the oil phase is collected after standing.

[0073] In a preferred embodiment, the oxidizing solution is concentrated after step (1') and before step (1) to obtain an oxidizing solution with a cumene hydroperoxide concentration of 40-70 wt%.

[0074] In a preferred embodiment, the material containing α,α-dimethylbenzyl alcohol is subjected to water washing and / or adsorption treatment before the conversion treatment in step (2) to remove titanium, silicon and aluminum elements therein.

[0075] In a preferred embodiment, when the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2), the weight ratio of water to the material containing α,α-dimethylbenzyl alcohol is (2-0.1):1, preferably (1-0.2):1.

[0076] For example, when the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2), the weight ratio of water to the material containing α,α-dimethylbenzyl alcohol is 2:1, 1.5:1, 1.2:1, 1:1, 0.8:1, 0.6:1, 0.5:1, 0.4:1, 0.3:1, 0.2:1 or 0.1:1.

[0077] In a further preferred embodiment, when the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2), the washing is carried out at 0-50°C and 0-1MPa, preferably at room temperature and pressure.

[0078] For example, when the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2), the washing temperature is 0°C, 10°C, 20°C, 25°C, 30°C, 35°C, 40°C or 50°C; and the washing pressure is 0MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa or 1MPa.

[0079] In a preferred embodiment, when the material containing α,α-dimethylbenzyl alcohol is subjected to adsorption treatment after step (1) and before step (2), the adsorption treatment is carried out in the presence of an adsorbent selected from at least one of the following adsorbent materials: alumina, activated carbon, silica, diatomaceous earth, cordierite, zeolite, and ion exchange resin.

[0080] For example, the adsorbent can be industrially mature modified alumina.

[0081] In a further preferred embodiment, the adsorption is carried out at 40-200℃ and 0.1-2.0 MPa, preferably at 50-100℃ and 0.1-1 MPa.

[0082] For example, the adsorption temperature is 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 120℃, 150℃, 180℃ or 200℃; the adsorption pressure is 0MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa or 1MPa.

[0083] In a further preferred embodiment, the adsorption treatment is carried out using an adsorbent bed, wherein the mass hourly space velocity (HHSV) of α,α-dimethylbenzyl alcohol in the adsorbent bed is 0.1–10 h⁻¹. -1 Preferably 0.3 to 5 hours -1 .

[0084] For example, the adsorption treatment is carried out using an adsorbent bed, wherein the mass hourly space velocity (HHSV) of α,α-dimethylbenzyl alcohol in the adsorbent bed is 0.1 h⁻¹. -1 0.5h -1 1h -1 2h -1 3h -1 4h -1 5h -1 6h -1 7h -1 0.1h -1 8h -1 9h -1 or 10h -1 .

[0085] Preferably, before step (2), the material containing α,α-dimethylbenzyl alcohol first passes through an adsorption bed filled with the adsorbent.

[0086] The specific removal methods are not limited to washing and adsorption, as long as they can control the titanium, silicon and aluminum elements in the DMAB material to below 1 ppm (preferably not including 1 ppm).

[0087] The second objective of this invention is to provide cumene obtained by the preparation method described in the first objective of this invention.

[0088] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; 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. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0089] Compared with the prior art, the present invention has the following beneficial effects: by strictly controlling the titanium, silicon and aluminum elements in the raw materials entering the DMBA conversion process, the present invention can ensure that the DMBA conversion rate will not decrease significantly during long-term operation without affecting the DMBA conversion activity. Detailed Implementation

[0090] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0091] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0092] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0093] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0094] The superhydrophobic titanium-containing porous silica catalyst used in the examples and comparative examples is the one described in Example 1 of CN104437618A. The preparation method of the titanium-containing porous silica / alumina catalyst is described in Example 8.

[0095] The elemental contents in the examples and comparative examples were detected by atomic emission spectrometry (ICP).

[0096]

Example 1

[0097] Oxidation process: Under the conditions of 105℃, 0.4MPa, and controlling the oxygen volume content of the tail to be less than 5%, the cumene stream is oxidized with air to obtain a hydrogen peroxide cumene (CHP) oxidized liquid with a weight concentration of 20-24%.

[0098] The cumene hydrogen peroxide oxidation solution was washed with a 2% NaOH aqueous solution, with a volume ratio of 3:1 between the oxidizing solution and the alkaline solution, to remove the organic acids.

[0099] The oxidation solution was then washed with deionized water at 40°C to remove residual Na from the alkaline washing.+ The volume ratio of the oxidizing solution to deionized water was 1:1. After washing with water, the oil phase was collected after standing.

[0100] To meet the requirements of the epoxidation reaction, the solution was vacuum concentrated at 75°C to obtain an oxidizing solution with a cumene hydroperoxide concentration of 50% by weight. During the concentration process, residual water from washing was also removed to some extent. After treatment, the cumene hydroperoxide oxidizing solution contained 200 ppm of organic acids, 200 ppm of H₂O, and Na₂O. + The weight content is 1 ppm.

[0101] Epoxidation process: The above-mentioned cumene hydroperoxide oxidant (CHP concentration of 50 wt%) was subjected to a selective redox reaction with propylene in a fixed-bed reactor in the presence of a superhydrophobic titanium-containing porous silica catalyst to produce propylene oxide and α,α-dimethylbenzyl alcohol. The reaction conditions for propylene and cumene hydroperoxide were: reaction temperature of 150℃, reaction absolute pressure of 8.0 MPa, molar ratio of propylene to cumene hydroperoxide of 15, cumene hydroperoxide feed concentration of 90 wt%, and cumene hydroperoxide weight hourly space velocity of 15 h⁻¹. -1 .

[0102] The reaction mixture is passed into a propylene recovery tower to recover excess propylene for recycling. The propylene recovery tower operates at atmospheric pressure, with a top temperature of -4.5°C and a bottom temperature of 150°C. The bottom material containing propylene oxide, α,α-dimethylbenzyl alcohol, and cumene, etc., enters a propylene oxide separation tower, which operates at atmospheric pressure, with a top temperature of 66°C and a bottom temperature of 160°C.

[0103] Before contacting hydrogen, the cumene solution containing α,α-dimethylbenzyl alcohol (containing 55% α,α-dimethylbenzyl alcohol) obtained from the bottom of the propylene oxide separation tower was washed with deionized water at 40°C to remove titanium from the material. The weight ratio of water to the cumene solution containing α,α-dimethylbenzyl alcohol was 1:1. After washing, the titanium content of the cumene solution containing α,α-dimethylbenzyl alcohol was 0.1 ppm, and the total content of titanium, silicon and aluminum was less than 0.3 ppm.

[0104] DMBA conversion process: At a reaction temperature of 160℃ and a pressure of 2.0MPa, the molar ratio of H2 / DMBA is 6:1, and the mass hourly space velocity (HHSV) of DMBA is 1 h⁻¹. -1 After 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%.

[0105]

Example 2

[0106] Oxidation process: Same as in Example 1

[0107] Epoxidation process: Same as in Example 1.

[0108] An adsorption bed containing alumina inert ceramic balls is set up before the DMBA conversion process. An isopropylbenzene solution containing α,α-dimethylbenzyl alcohol is introduced into this adsorption bed at a space velocity of 2 h⁻¹. -1 At a temperature of 100℃ and a pressure of 1.0MPa, after treatment, the titanium content in the cumene solution containing α,α-dimethylbenzyl alcohol was 0ppm, and the total content of titanium, silicon and aluminum was less than 0.1ppm.

[0109] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%.

[0110]

Example 3

[0111] Oxidation process: Same as in Example 1

[0112] Epoxidation process: Same as in Example 1.

[0113] An adsorption bed containing alumina inert ceramic balls is set up before the DMBA conversion process. A cumene solution containing α,α-dimethylbenzyl alcohol is introduced into this adsorption bed at a space velocity of 0.5 h⁻¹. -1 At a temperature of 100℃ and a pressure of 1.0MPa, after treatment, the titanium content in the cumene solution containing α,α-dimethylbenzyl alcohol was 0ppm, and the total content of titanium, silicon and aluminum was less than 0.1ppm.

[0114] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%.

[0115]

Example 4

[0116] Oxidation process: Same as in Example 1

[0117] Epoxidation process: Same as in Example 1.

[0118] An adsorption bed containing alumina inert ceramic balls is set up before the DMBA conversion process. An isopropylbenzene solution containing α,α-dimethylbenzyl alcohol is introduced into this adsorption bed at a space velocity of 5 h⁻¹. -1At a temperature of 100℃ and a pressure of 1.0MPa, after treatment, the Ti content in the cumene solution containing α,α-dimethylbenzyl alcohol was 0.1ppm, and the total content of titanium, silicon and aluminum was less than 0.2ppm.

[0119] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%.

[0120]

Example 5

[0121] Oxidation process: Same as in Example 1

[0122] Epoxidation process: Same as in Example 1.

[0123] An adsorption bed containing alumina inert ceramic balls is set up before the DMBA conversion process. An isopropylbenzene solution containing α,α-dimethylbenzyl alcohol is introduced into this adsorption bed at a space velocity of 10 h⁻¹. -1 At a temperature of 100℃ and a pressure of 1.0MPa, after treatment, the total content of titanium, silicon and aluminum in the cumene solution containing α,α-dimethylbenzyl alcohol is less than 1ppm.

[0124] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 98.0%, and the cumene selectivity was greater than 99.85%.

[0125]

Example 6

[0126] The process of Example 1 was repeated, except that when the material containing α,α-dimethylbenzyl alcohol was washed with water, the weight ratio of water to cumene solution containing α,α-dimethylbenzyl alcohol was 0.2:1, and the water temperature was 50°C.

[0127] After treatment, the total content of titanium, silicon and aluminum in the cumene solution containing α,α-dimethylbenzyl alcohol is less than 1 ppm.

[0128] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 98.0%, and the cumene selectivity was greater than 99.85%.

[0129]

Example 7

[0130] The process of Example 1 was repeated, except that when the material containing α,α-dimethylbenzyl alcohol was washed with water, the weight ratio of water to cumene solution containing α,α-dimethylbenzyl alcohol was 0.5:1, and the water temperature was 30°C.

[0131] After treatment, the total content of titanium, silicon and aluminum in the cumene solution containing α,α-dimethylbenzyl alcohol is less than 1 ppm.

[0132] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 98.0%, and the cumene selectivity was greater than 99.85%.

[0133]

Example 8

[0134] Oxidation process: Same as in Example 1.

[0135] Epoxidation process: Same as in Example 1, except that the epoxidation catalyst used is a titanium-containing porous silica / alumina catalyst. The preparation method of the titanium-containing porous silica / alumina catalyst is as follows:

[0136] Titanium-containing porous silica catalyst raw powder was prepared according to Example 1 of CN104437618A; 80g of titanium-containing porous silica catalyst raw powder and 10g of alumina raw powder were mixed, and 1g of guar gum powder, 1g of 5% PVA aqueous solution, 0.1g of nitric acid and 0.1g of acetic acid were added, kneaded and extruded using a φ2.2mm mold, dried at 100℃ overnight, and calcined at 900℃ for 4h to obtain titanium-containing porous silica / alumina catalyst.

[0137] DMBA raw material processing procedure: Same as in Example 2. After processing, the titanium content in the cumene solution containing α,α-dimethylbenzyl alcohol is 0 ppm, and the total content of titanium, silicon and aluminum is less than 0.1 ppm.

[0138] DMBA conversion process: Same as Example 1, after 100 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%. After 200 hours of operation, the DMBA conversion rate was greater than 99.0%, and the cumene selectivity was greater than 99.85%.

[0139] Comparative Example 1

[0140] Oxidation process: Same as in Example 1.

[0141] Epoxidation process: Same as in Example 1.

[0142] The cumene solution containing α,α-dimethylbenzyl alcohol (containing 55% α,α-dimethylbenzyl alcohol) obtained from the bottom of the propylene oxide separation tower was not subjected to detitanium treatment before contacting with hydrogen.

[0143] DMBA conversion process: Same as Example 1. The titanium content of this material is 1-5 ppm (initially, the detected Ti content is around 1 ppm, but as the running time increases, the Ti content gradually increases, reaching 5 ppm). After 100 hours of operation, the DMBA conversion rate is greater than 99.0%, and the cumene selectivity is greater than 99.85%. After 200 hours of operation, the DMBA conversion rate is greater than 97.7%, and the cumene selectivity is greater than 99.85%.

[0144] The comparative example was the same as in Example 1, but without DMBA feedstock treatment and with a higher titanium content. It was found that the DMBA conversion rate decreased after long-term operation. The possible reasons are: (1) the lost titanium elements are enriched on the DMBA conversion catalyst, resulting in: (1) decreased catalyst activity; (2) increased bed pressure drop or even blockage of the reaction tube.

[0145] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for preparing cumene, comprising: (1) The material containing cumene peroxide is reacted with propylene, and the reaction products are separated to obtain the material containing propylene oxide and the material containing α,α-dimethylbenzyl alcohol respectively; step (1) is carried out in the presence of a solid catalyst, wherein the solid catalyst is selected from at least one of titanium-containing silicon oxide, titanium-containing aluminum oxide, and titanium-containing silicon-aluminum oxide. (2) The material containing α,α-dimethylbenzyl alcohol is converted to obtain cumene material; In this process, after step (1) and before step (2), the material containing α,α-dimethylbenzyl alcohol is subjected to water washing and / or adsorption treatment to control the total content of titanium, silicon and aluminum in the material to be less than 1 ppm; the adsorption treatment is carried out in the presence of an adsorbent, which is selected from at least one of alumina, activated carbon, silica, diatomaceous earth, cordierite, zeolite and ion exchange resin.

2. The preparation method according to claim 1, characterized in that, The total content of titanium, silicon and aluminum in the material containing α,α-dimethylbenzyl alcohol described in step (2) is less than 0.6 ppm.

3. The preparation method according to claim 1, characterized in that, The total content of titanium, silicon and aluminum in the material containing α,α-dimethylbenzyl alcohol described in step (2) is less than 0.3 ppm.

4. The preparation method according to claim 1, characterized in that, In step (1): The reaction temperature is controlled at 25–200℃, and the reaction pressure is controlled at 0.1–10 MPa; and / or The molar ratio of propylene to cumene peroxide is controlled at (2–30):1; and / or The reactants were subjected to distillation to obtain materials containing propylene oxide and materials containing α,α-dimethylbenzyl alcohol.

5. The preparation method according to claim 1, characterized in that, In step (1): The reaction temperature is controlled at 50–150℃, and the reaction pressure is controlled at 0.4–8 MPa; and / or The molar ratio of propylene to cumene peroxide is controlled to be (4-20):

1.

6. The preparation method according to claim 1, characterized in that, The conversion process in step (2) is carried out as follows: first dehydration treatment followed by hydrogenation treatment.

7. The preparation method according to claim 6, characterized in that, The dehydration and hydrogenation processes are performed as follows: (2.1) Dehydration treatment: In the presence of a catalyst, the material containing α,α-dimethylbenzyl alcohol is subjected to a dehydration reaction to obtain the material containing α-methylstyrene; (2.2) Hydrogenation treatment: In the presence of a catalyst, the material containing α-methylstyrene is reacted with hydrogen to obtain cumene material.

8. The preparation method according to claim 7, characterized in that, The dehydration and hydrogenation processes are performed as follows: In the dehydration process, the reaction temperature is 50–400°C; and / or the reaction pressure is 0.1–6 MPa. In the hydrogenation process, the molar ratio of hydrogen to α-methylstyrene is (1-15):1; and / or, the reaction temperature is 0-500°C; and / or, the reaction pressure is 0.1-10 MPa.

9. The preparation method according to claim 6, characterized in that, In the dehydration process, the catalyst is selected from solid acid catalysts; and / or In the hydrogenation process, the catalyst comprises a support and a metal component supported on the support.

10. The preparation method according to claim 9, characterized in that, In the dehydration process, the catalyst is at least one selected from alumina, amorphous silica-alumina oxide, acidic clay, and zeolite molecular sieve; and / or The carrier is selected from at least one of alumina, silica, and activated carbon, and / or the metal component is selected from at least one metal of Group VIII and Group IB.

11. The preparation method according to claim 1, characterized in that, The conversion process described in step (2) is a direct hydrogenolysis process; The direct hydrogenolysis process is carried out as follows: in the presence of a catalyst, the material containing α,α-dimethylbenzyl alcohol is mixed with hydrogen gas, and the reaction yields cumene.

12. The preparation method according to claim 11, characterized in that, In the direct hydrogenolysis process, the reaction temperature is 0–300°C, and / or the reaction pressure is 0–5 MPa, and / or the space velocity of the material containing α,α-dimethylbenzyl alcohol is 0.5–2 h⁻¹. -1 .

13. The preparation method according to claim 11, characterized in that, In the direct hydrogenolysis process, the molar ratio of hydrogen to α,α-dimethylbenzyl alcohol is (2–15):1; and / or In the direct hydrogenolysis process, the catalyst comprises a support and a metal component supported on the support.

14. The preparation method according to claim 13, characterized in that, In the direct hydrogenolysis process, the molar ratio of hydrogen to α,α-dimethylbenzyl alcohol is (3–9):1; and / or The carrier is selected from at least one of alumina, silica, and activated carbon, and / or the metal component is selected from at least one metal of Group VIII and Group IB.

15. The preparation method according to claim 1, characterized in that, The material containing cumene peroxide in step (1) is obtained as follows: (1') The material containing cumene is subjected to oxidation treatment to obtain the material containing cumene peroxide. In step (1'): The oxidation treatment is carried out at 50–200°C and 0–5 MPa; and / or, The oxidation treatment is carried out under oxygen-containing gas; and / or, Alkali washing is performed during or after the oxidation process.

16. The preparation method according to claim 15, characterized in that, After the alkaline washing, a water wash is performed.

17. The preparation method according to claim 1, characterized in that, When the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2): The weight ratio of water to the material containing α,α-dimethylbenzyl alcohol is (2–0.1):1; and / or, The water washing is carried out at 0-50℃ and 0-1MPa.

18. The preparation method according to claim 1, characterized in that, When the material containing α,α-dimethylbenzyl alcohol is washed with water after step (1) and before step (2): The weight ratio of water to the material containing α,α-dimethylbenzyl alcohol is (1–0.2):1; and / or, The water washing is carried out at normal temperature and pressure.

19. The preparation method according to claim 1, characterized in that, The adsorption was carried out at 40-200℃ and 0.1-2.0 MPa. The adsorption treatment is carried out using an adsorbent bed, wherein the mass hourly space velocity (HHSV) of α,α-dimethylbenzyl alcohol in the adsorbent bed is 0.1–10 h⁻¹. -1 .

20. The preparation method according to claim 1, characterized in that, The adsorption was carried out at 50-100℃ and 0.1-1 MPa. The adsorption treatment is carried out using an adsorbent bed, wherein the mass hourly space velocity (HHSV) of α,α-dimethylbenzyl alcohol in the adsorbent bed is 0.3–5 h⁻¹. -1 .