A device and method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol

Abstract

The present invention relates to a device and method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the device comprising a first hydrogenation reactor, a flash separator, a second hydrogenation reactor and a deweighting device connected in sequence; an organic acid adding device is arranged at the raw material inlet of the first hydrogenation reactor; a flash separator is arranged at the reactant outlet of the first hydrogenation reactor, and a liquid phase product obtained by the flash separator flows into the second hydrogenation reactor. The method is carried out in the device, and the present invention improves the acidity of the reaction system of the first hydrogenation reaction by mixing the raw material containing α,α-dimethylbenzyl alcohol with an organic acid, so that the first hydrogenation reaction can be carried out at a lower temperature, which not only reduces the unit consumption of cumene, but also avoids the problem of increased by-products caused by increased temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of propylene oxide preparation, designs a method for preparing cumene, and particularly relates to a device and method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. Background Art

[0002] Propylene oxide (PO) is an important organic chemical raw material, mainly used to produce polyether polyols, propylene glycol, propylene glycol ether, etc. At present, the commercial production methods of PO mainly include chlorohydrin method, co-oxidation method and direct oxidation method with hydrogen peroxide (HPPO method). Among them, the chlorohydrin method has the disadvantages of serious equipment corrosion, large amount of wastewater and solid waste, and serious environmental pollution. The direct oxidation method with hydrogen peroxide (HPPO method) has the disadvantages of high cost of hydrogen peroxide and poor economic efficiency.

[0003] The co-oxidation method, also known as the co-production method or indirect oxidation method, is to generate propylene oxide through the reaction of organic peroxide and propylene, and produce organic alcohol as a by-product, mainly including PO / TBA (MTBE), PO / SM and PO / CHP. Among them, PO / TBA (MTBE) has the disadvantages of a long process and large equipment investment; PO / SM method has the disadvantages of a long process, large equipment investment and large amount of wastewater and waste gas.

[0004] The PO / CHP process is a cumene co-oxidation process, which includes three core reactions: cumene peroxidation, propylene epoxidation, and α,α-Cumyl Alcohol (CA) hydrogenolysis, as well as related refining steps. Propylene and cumene peroxidation generate PO and α,α-Cumyl Alcohol, which are then hydrogenated to generate cumene. Cumene is then refined and then peroxidized to obtain cumene hydroperoxide, thereby achieving the recycling of cumene.

[0005] Compared with other co-oxidation processes, the cumene co-oxidation process has the advantages of short process route, low equipment investment and no by-products. However, the reaction process of α,α-dimethylbenzyl alcohol liquid phase hydrogenolysis to generate cumene is difficult to control, dimethylbenzyl alcohol is easily polymerized after dehydration to generate α-methylstyrene (AMS), and there is also the defect of over-hydrogenation to generate isopropylcyclohexane and difficulty in separating the product.

[0006] CN 112473734A discloses a method for preparing cumene by reactive distillation coupled with hydrogenation reaction of dimethylbenzyl alcohol, comprising the following steps: a dimethylbenzyl alcohol stream containing cumene enters a reactive distillation tower, heavy impurities are extracted from the bottom of the tower, and the enriched dimethylbenzyl alcohol enters a reactive distillation section loaded with an acidic catalyst, and dimethylbenzyl alcohol is dehydrated in the reactive distillation section to generate AMS and water; AMS, water and cumene are rectified and separated to the top of the tower for extraction, and the AMS, water and cumene at the top of the tower are separated by a coalescer, and the stream containing cumene and AMS is hydrogenated by a hydrogenation reactor to generate cumene. The acidic catalyst is a cationic acidic resin, a metal oxide, an acidic zeolite molecular sieve, a solid heteropoly acid, or an acidic ionic liquid supported catalyst, thereby solving the problems of poor selectivity, poor stability, short life and high cost of the catalyst for direct hydrogenolysis of dimethylbenzyl alcohol.

[0007] CN 113070060A discloses a catalyst for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, and its preparation method and use. The preparation method comprises the following steps: (1) preparing an alkaline earth metal compound solution and two palladium source solutions with different pH values ​​of pH <2 and 7> pH ≥3; (2) pre-treating the activated carbon, impregnating the alkaline earth metal solution, aging, filtering, drying and roasting; (3) impregnating the two palladium source solutions in two steps, and performing aging, washing, drying and roasting steps after each impregnation. The method of impregnating the carrier in steps with different palladium sources solves the problem of low utilization rate of active components in hydrogenolysis of α,α-dimethylbenzyl alcohol, reduces the reaction temperature, inhibits the occurrence of side reactions, and improves the selectivity of the catalyst.

[0008] CN 113058628A discloses a Pd-C catalyst for preparing cumene by hydrogenolysis and a preparation method thereof. The catalyst comprises the following components by weight: a) 0.057-2.3% palladium Pd; b) 97.7-99.943% of any one or more of carrier activated carbon, zirconium dioxide or titanium dioxide. The preparation method comprises carrier treatment, active component loading, drying and roasting to prepare the catalyst. The preparation method improves the dispersion of the catalyst by controlling the particle size of the active component, inhibits the formation of cumene cyclohexane, and improves the conversion rate of dimethylbenzyl alcohol and the yield of cumene.

[0009] Although the above method can improve the conversion rate of dimethylbenzyl alcohol and the yield of cumene in the cumene co-oxidation process, the main improvements are the improvements of the catalyst used, and do not involve the improvement of the relevant processes in the cumene co-oxidation process. Therefore, a process improvement is provided to improve the conversion rate of dimethylbenzyl alcohol and the yield of cumene, which can further reduce the cost of preparing cumene by the cumene co-oxidation process. Summary of the invention

[0010] The object of the present invention is to provide a device and method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. The method performs two-stage hydrogenolysis on α,α-dimethylbenzyl alcohol, wherein the first stage hydrogenolysis can be performed at a relatively low temperature, thereby reducing the energy consumption of the hydrogenolysis, and then cooperates with the second stage hydrogenolysis to ensure the conversion rate of the α,α-dimethylbenzyl alcohol, thereby reducing the unit consumption of cumene as a whole and improving the economy of the cumene co-oxidation circulation process.

[0011] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a device for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the device comprising a first hydrogenation reactor, a flash separator, a second hydrogenation reactor and a deweighting device connected in sequence.

[0013] An organic acid adding device is provided at the raw material inlet of the first hydrogenation reactor.

[0014] A flash separator is arranged at the reactant outlet of the first hydrogenation reactor, and the liquid phase product obtained by the flash separator flows into the second hydrogenation reactor.

[0015] The α,α-dimethylbenzyl alcohol is subjected to a first hydrogenation reaction in a first hydrogenation reactor, and a second hydrogenation reaction is carried out in a second hydrogenation reactor. The product of the first hydrogenation reaction is separated from water and organic acid in a flash separator. The second hydrogenation product is subjected to a de-heaving treatment in a de-heaving device to obtain a heavy component containing bibenzyl and a light component cumene.

[0016] The present invention provides an organic acid adding device at the raw material inlet of the first hydrogenation reactor, thereby improving the acidity of the reaction system in the first hydrogenation reactor, thereby reducing the temperature required for the first hydrogenation reaction, not only reducing the unit consumption of isopropylbenzene, but also reducing the generation of by-product benzene ring hydrogenation products.

[0017] Preferably, the heavy component outlet of the deweighting device is connected to the feed inlet of the second hydrogenation reactor.

[0018] The second hydrogenation product is subjected to a de-weighting treatment in a de-weighting device to obtain a heavy component containing 15-45wt% of bibenzyl. The outlet of the heavy component is connected to the feed port of the second hydrogenation reactor to achieve the recycling of the bibenzyl. The bibenzyl is converted into cumene through the second hydrogenation reaction, thereby reducing the consumption of cumene caused by the generation of by-products.

[0019] Preferably, a first catalyst is arranged in the first hydrogenation reactor; the first catalyst is a Pd-A / SiO2-Al2O3 catalyst, wherein A is any one of B2O3, La2O3, CeO2 or MnO2 or a combination of at least two thereof, typical but non-limiting combinations include a combination of B2O3 and La2O3, a combination of La2O3 and CeO2, a combination of CeO2 and MnO2, a combination of B2O3, La2O3 and CeO2, a combination of La2O3, CeO2 and MnO2, or a combination of B2O3, La2O3, CeO2 and MnO2.

[0020] The SiO2-Al2O3 in the first catalyst has strong acidity, and the acidity of the first catalyst can be further improved by adding the auxiliary agent A, thereby cooperating with the organic acid provided by the organic acid adding device to enable the first hydrogenation reactor to react at a lower hydrogenation temperature.

[0021] Preferably, based on the mass percentage of the first catalyst as 100wt%, the mass percentage of Pd is 0.05-2wt%, for example, it can be 0.05wt%, 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt% or 2wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, based on the mass percentage of the first catalyst as 100wt%, the mass percentage of A is 1-4wt%, for example, it can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt% or 4wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, based on the mass percentage of the first catalyst as 100wt%, the mass percentage of the carrier SiO2-Al2O3 is 94-98.95wt%, for example, it can be 94wt%, 94.5wt%, 95wt%, 96wt%, 97wt%, 98wt% or 98.95wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] The sum of the mass percentages of Pd, A and the carrier SiO2-Al2O3 in the first catalyst is 100wt%.

[0025] Preferably, SiO2 in the carrier SiO2-Al2O3 is 30-65wt% of the total mass of the carrier, for example, it can be 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt% or 65wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, and the balance is Al2O3.

[0026] The preparation method of the first catalyst Pd-A / SiO2-Al2O3 catalyst of the present invention comprises the following steps:

[0027] (a) mixing an aluminum source, a silicon source and an organic solvent, heating the mixture to 40-60° C., then adding an auxiliary agent A for hydrolysis, dropping a pH regulator during the hydrolysis process to control the pH to 8-10, and aging the mixture after the hydrolysis to obtain an aged slurry;

[0028] (b) filtering, drying and calcining the aged slurry obtained in step (a) to obtain a carrier containing additive A;

[0029] (c) The support containing the additive A obtained in step (b) is impregnated into a Pd source solution, and then dried and calcined to obtain the first catalyst.

[0030] The aluminum source in step (a) includes but is not limited to aluminum isopropoxide; the silicon source in step (a) includes but is not limited to ethyl silicate; the pH adjuster in step (a) includes but is not limited to aqueous ammonia.

[0031] Preferably, the hydrolysis temperature in step (a) is 40-60°C, for example, 40°C, 42°C, 45°C, 48°C, 50°C, 54°C, 56°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the hydrolysis time in step (a) is 0.5-2 h, for example, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.6 h, 1.8 h or 2 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, ultrasonic treatment is used during the hydrolysis process in step (a). Ultrasonic treatment allows the auxiliary agent A to be evenly dispersed, thereby helping to improve the hydrolysis effect.

[0034] Preferably, the aging temperature in step (a) is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the aging time in step (a) is 2-4 h, for example, 2 h, 2.5 h, 3 h, 3.5 h or 4 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] The platinum source in step (c) is a conventional soluble platinum source in the art, including but not limited to chloroplatinic acid.

[0037] The impregnation in step (c) is carried out under reflux conditions, the impregnation temperature is 60-80°C, for example, it can be 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time is 2-4h, for example, it can be 2h, 2.5h, 3h, 3.5h or 4h, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0038] After the impregnation in step (c) is completed, the catalyst is air-dried, washed, and then dried and calcined to obtain the first catalyst.

[0039] Preferably, a second catalyst is arranged in the second hydrogenation reactor; the second catalyst is a Pd / C catalyst.

[0040] Preferably, based on the mass percentage of the second catalyst as 100wt%, the mass percentage of Pd is 0.05-2wt%, for example, it can be 0.05wt%, 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt% or 2wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; the mass percentage of carrier C is 98-99.95wt%, for example, it can be 98wt%, 98.5wt%, 99wt%, 99.5wt% or 99.95wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0041] The sum of the mass percentages of Pd and carrier C in the second catalyst is 100 wt %.

[0042] The preparation method of the second catalyst Pd / C of the present invention comprises the following steps:

[0043] (I) mixing activated carbon and nitric acid, reflux heating, washing and drying to obtain a modified carrier;

[0044] (II) The modified support obtained in step (I) is impregnated into a Pd source solution, and then dried and calcined to obtain the second catalyst.

[0045] Preferably, the concentration of nitric acid in step (I) is 12-16wt%, for example, 12wt%, 13wt%, 14wt%, 15wt% or 16wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the reflux heating temperature in step (I) is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable; the time is 2-4h, for example, 2h, 2.5h, 3h, 3.5h or 4h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] The end point of the washing in step (I) is to make the washing solution neutral.

[0048] The platinum source in step (II) is a conventional soluble platinum source in the art, including but not limited to chloroplatinic acid.

[0049] Preferably, the impregnation in step (II) is carried out under reflux conditions, the impregnation temperature is 60-80°C, for example, it can be 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time is 2-4h, for example, it can be 2h, 2.5h, 3h, 3.5h or 4h, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0050] The flash separator described in the first aspect of the present invention is used to flash remove water and organic acid from the first hydrogenation product to prevent the organic acid from entering the second hydrogenation reactor. As a preferred technical solution, the organic acid obtained by the flash separator is recycled to the first hydrogenation reactor.

[0051] In a second aspect, the present invention provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0052] (1) mixing a raw material containing α,α-dimethylbenzyl alcohol with an organic acid and hydrogen, performing a first hydrogenation reaction, and flash evaporating to separate water and the organic acid to obtain a first hydrogenation product;

[0053] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen and subjected to a second hydrogenation reaction. The second hydrogenation product is subjected to a de-heavy treatment to obtain an isopropylbenzene product.

[0054] The present invention improves the acidity of the reaction system of the first hydrogenation reaction by mixing the raw material containing α,α-dimethylbenzyl alcohol with an organic acid, so that the first hydrogenation reaction can be carried out at a lower temperature, which not only reduces the unit consumption of isopropylbenzene, but also avoids the problem of increased by-products caused by increased temperature.

[0055] Preferably, the α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 18-28wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

[0056] In the α,α-dimethylbenzyl alcohol-containing raw material, the mass percentage of α,α-dimethylbenzyl alcohol is 18-28wt%, for example, it can be 18, 20, 21, 24, 25, 27 or 28, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] The mass percentage of propylene oxide in the α,α-dimethylbenzyl alcohol-containing raw material is ≤500 ppm, for example, it can be 100 ppm, 200 ppm, 300 ppm, 400 ppm or 500 ppm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0058] In the α,α-dimethylbenzyl alcohol-containing raw material, the mass percentage of cumene hydroperoxide is ≤3000ppm, for example, it can be 20ppm, 100ppm, 200ppm, 300ppm, 500ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm or 3000ppm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] In the α,α-dimethylbenzyl alcohol-containing raw material, the mass percentage of phenol is ≤2000ppm, for example, it can be 50ppm, 100ppm, 200ppm, 500ppm, 1000ppm, 1200ppm, 1500ppm, 1600ppm, 1800ppm or 2000ppm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] Preferably, the organic acid in step (1) comprises any one of benzenesulfonic acid, o-toluenesulfonic acid or p-toluenesulfonic acid or a combination of at least two thereof, and typical but non-limiting combinations include a combination of benzenesulfonic acid and o-toluenesulfonic acid, a combination of o-toluenesulfonic acid and p-toluenesulfonic acid, a combination of benzenesulfonic acid and p-toluenesulfonic acid, or a combination of benzenesulfonic acid, o-toluenesulfonic acid and p-toluenesulfonic acid.

[0061] Preferably, the amount of the organic acid added in step (1) is 0.01-0.2wt% of the raw material containing α,α-dimethylbenzyl alcohol, for example, it can be 0.01wt%, 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.15wt%, 0.18wt% or 0.2wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0062] The present invention can reduce the temperature required for the first hydrogenation reaction by adding an organic acid during the first hydrogenation reaction, thereby effectively reducing the generation of by-products. When the amount of organic acid added is small, the purpose of reducing the temperature of the first hydrogenation reaction cannot be achieved; when the amount of organic acid added is large, the temperature of the first hydrogenation reaction cannot be further reduced, and the burden of subsequent flash separation is increased.

[0063] Preferably, the catalyst used in the first hydrogenation reaction in step (1) is the first catalyst.

[0064] The first catalyst is a Pd-A / SiO2-Al2O3 catalyst, wherein A is any one of B2O3, La2O3, CeO2 or MnO2, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of B2O3 and La2O3, a combination of La2O3 and CeO2, a combination of CeO2 and MnO2, a combination of B2O3, La2O3 and CeO2, a combination of La2O3, CeO2 and MnO2, or a combination of B2O3, La2O3, CeO2 and MnO2.

[0065] The SiO2-Al2O3 in the first catalyst has strong acidity, and the addition of the auxiliary agent A can further enhance the acidity of the first catalyst, thereby cooperating with the organic acid provided by the organic acid adding device to enable the first hydrogenation reaction to proceed at a lower hydrogenation temperature.

[0066] Preferably, the gauge pressure of the first hydrogenation reaction in step (1) is 1.5-3 MPa, for example, 1.5 MPa, 1.8 MPa, 2 MPa, 2.5 MPa, 2.8 MPa or 3 MPa, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the temperature is 120-140°C, for example, 120°C, 125°C, 130°C, 135°C or 140°C, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0067] Preferably, the liquid hourly space velocity of the first hydrogenation reaction in step (1) is 1-3h -1 , for example, it can be 1h -1 , 1.5h -1 , 2h -1 , 2.5h-1 or 3h -1 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0068] Preferably, the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol in the first hydrogenation reaction in step (1) is (100-300):1, for example, it can be 100:1, 150:1, 200:1, 250:1 or 300:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0069] The volume ratio of hydrogen to α,α-dimethylbenzyl alcohol in the first hydrogenation reaction of the present invention refers to the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol in the raw material containing α,α-dimethylbenzyl alcohol. Exemplarily, if the volume ratio of hydrogen to the raw material containing α,α-dimethylbenzyl alcohol in the first hydrogenation reaction of step (1) is 100:100, and the volume concentration of α,α-dimethylbenzyl alcohol in the raw material containing α,α-dimethylbenzyl alcohol is 1%, then the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 100:1.

[0070] Preferably, the catalyst used in the second hydrogenation reaction in step (2) is a second catalyst; and the second catalyst is a Pd / C catalyst.

[0071] Preferably, the gauge pressure of the second hydrogenation reaction in step (2) is 1.5-3 MPa, for example, 1.5 MPa, 1.8 MPa, 2 MPa, 2.5 MPa, 2.8 MPa or 3 MPa, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the temperature is 150-170°C, for example, 150°C, 155°C, 160°C, 165°C or 170°C, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0072] Preferably, the liquid hourly space velocity of the second hydrogenation reaction in step (2) is 1-3h -1 , for example, it can be 1h -1 , 1.5h -1 , 2h -1 , 2.5h -1 or 3h -1 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0073] The hydrogen required for the second hydrogenation reaction in step (2) of the present invention comes from the first hydrogenation reaction.

[0074] Preferably, the light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to be mixed with the first hydrogenation product, and then subjected to a second hydrogenation reaction.

[0075] After the first hydrogenation reaction and the second hydrogenation reaction of the present invention, the heavy components obtained after the de-heavy treatment are composed of: 15-45wt% of bibenzyl and ≤0.1wt% of α-styrene polymer, and the remainder is cumene.

[0076] The invention realizes the recycling of bibenzyl by reusing the heavy components containing bibenzyl. Since bibenzyl can be hydrogenated to generate cumene, the consumption of cumene caused by the generation of by-products can be reduced.

[0077] Preferably, in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 0.01-3wt%, for example, it can be 0.01wt%, 0.05wt%, 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 2wt%, 2.5wt% or 3wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, preferably 0.1-1.5wt%.

[0078] As a preferred technical solution of the method described in the second aspect, the method comprises the following steps:

[0079] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the amount of the organic acid added is 0.01-0.2wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 1.5-3MPa, the temperature is 120-140°C, and the liquid hourly space velocity is 1-3h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is (100-300):1;

[0080] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 1.5-3 MPa, the temperature is 150-170°C, and the liquid hourly space velocity is 1-3 h -1 .

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] (1) The present invention increases the acidity of the reaction system in the first hydrogenation reactor by arranging an organic acid addition device at the raw material inlet of the first hydrogenation reactor, thereby reducing the temperature required for the first hydrogenation reaction, which not only reduces the unit consumption of isopropylbenzene, but also reduces the generation of by-product benzene ring hydrogenation products;

[0083] (2) The present invention realizes the recycling of bibenzyl by connecting the outlet of the heavy component to the feed port of the second hydrogenation reactor, converting the bibenzyl into cumene through the second hydrogenation reaction, thereby reducing the consumption of cumene caused by the generation of by-products;

[0084] (3) SiO2-Al2O3 in the first catalyst provided by the present invention has strong acidity, and the acidity of the first catalyst can be further improved by adding the auxiliary agent A, thereby cooperating with the organic acid provided by the organic acid adding device, so that the first hydrogenation reactor can react at a lower hydrogenation temperature;

[0085] (4) The present invention improves the acidity of the reaction system of the first hydrogenation reaction by mixing the raw material containing α,α-dimethylbenzyl alcohol with an organic acid, so that the first hydrogenation reaction can be carried out at a lower temperature, which not only reduces the unit consumption of isopropylbenzene, but also avoids the problem of increased by-products caused by increased temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 The present invention provides a schematic diagram of a device for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol.

[0087] Among them: 1, the first hydrogenation reactor; 11, the flash separator; 2, the second hydrogenation reactor; 3, the deweighting device. DETAILED DESCRIPTION

[0088] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0089] In order to facilitate the description of the technical solution provided by the present invention, the specific implementation mode of the present invention is carried out in the following device for hydrogenolysis of α,α-dimethylbenzyl alcohol to prepare isopropylbenzene, the structural schematic diagram of the device is as follows Figure 1 As shown, it comprises a first hydrogenation reactor 1, a flash separator 11, a second hydrogenation reactor 2 and a deweighting device 3 which are connected in sequence;

[0090] An organic acid adding device is provided at the raw material inlet of the first hydrogenation reactor 1;

[0091] A flash separator 11 is disposed at the reactant outlet of the first hydrogenation reactor 1 , and the liquid product obtained by the flash separator 11 flows into the second hydrogenation reactor 2 .

[0092] The heavy component outlet of the de-weighting device 3 is connected to the feed inlet of the second hydrogenation reactor 2 .

[0093] The α,α-dimethylbenzyl alcohol undergoes a first hydrogenation reaction in the first hydrogenation reactor 1, and a second hydrogenation reaction in the second hydrogenation reactor 2. The product of the first hydrogenation reaction is separated from water and organic acid in a flash separator 11. The second hydrogenation product is subjected to a de-heaving treatment in a de-heaving device 3 to obtain a heavy component containing bibenzyl and a light component cumene.

[0094] By setting an organic acid addition device at the raw material inlet of the first hydrogenation reactor 1, the acidity of the reaction system in the first hydrogenation reactor 1 is increased, thereby reducing the temperature required for the first hydrogenation reaction, not only reducing the unit consumption of cumene, but also reducing the generation of by-product benzene ring hydrogenation products. By connecting the heavy component outlet to the feed inlet of the second hydrogenation reactor 2, the recycling of bibenzyl is achieved, and the bibenzyl is converted into cumene through the second hydrogenation reaction, reducing the cumene material consumption caused by the generation of by-products.

[0095] The preparation method of the first catalyst Pd-A / SiO2-Al2O3 catalyst used in the first hydrogenation reactor 1 comprises the following steps:

[0096] (a) mixing with aluminum isopropoxide, ethyl silicate and anhydrous ethanol, heating to 50° C., then adding auxiliary agent A for hydrolysis, adding ammonia water dropwise during the hydrolysis process to control the pH value to 9; using ultrasonic treatment during the hydrolysis process, the hydrolysis temperature is 50° C., and the time is 1 h; after the hydrolysis is completed, aging is performed at 60° C. for 3 h to obtain an aged slurry;

[0097] (b) filtering, drying and calcining the aged slurry obtained in step (a) to obtain a carrier containing additive A;

[0098] (c) Under reflux conditions, the carrier containing the auxiliary agent A obtained in step (b) is immersed in a chloroplatinic acid solution at 70° C. for 3 hours, and then dried and calcined to obtain the first catalyst.

[0099] The preparation method of the second catalyst Pd / C catalyst used in the second hydrogenation catalyst 2 comprises the following steps:

[0100] (I) mixing activated carbon with nitric acid having a concentration of 15 wt %, heating under reflux at 70° C. for 3 h, washing and drying to obtain a modified carrier; the end point of the washing is to make the washing liquid neutral;

[0101] (II) Under reflux conditions, the modified carrier obtained in step (I) is immersed in a chloroplatinic acid solution at 70° C. for 3 hours, and then dried and calcined to obtain the second catalyst.

[0102] Example 1

[0103] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0104] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the organic acid is p-toluenesulfonic acid; the amount of the organic acid added is 0.1wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 2MPa, the temperature is 130°C, and the liquid hourly space velocity is 2h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 200:1;

[0105] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 2 MPa, the temperature is 160°C, and the liquid hourly space velocity is 2 h -1 ;

[0106] The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to be mixed with the first hydrogenation product, and then subjected to a second hydrogenation reaction; in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 1wt%.

[0107] The first catalyst is Pd-A / SiO2-Al2O3, and the auxiliary agent A is CeO2. Taking the mass percentage of the first catalyst as 100%, the mass percentage of Pd is 1wt%, the mass percentage of A is 2.5wt%, and the mass percentage of the carrier SiO2-Al2O3 is 96.5wt%; SiO2 in the carrier SiO2-Al2O3 accounts for 50wt% of the total weight of the carrier.

[0108] The second catalyst is a Pd / C catalyst. Taking the mass percentage of the second catalyst as 100%, the mass percentage of Pd is 1wt% and the mass percentage of the carrier C is 99wt%.

[0109] The α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 24wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

[0110] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤20ppm, the production of bibenzyl is ≤100ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0111] Example 2

[0112] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0113] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the organic acid is p-toluenesulfonic acid; the amount of the organic acid added is 0.05wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 2MPa, the temperature is 135°C, and the liquid hourly space velocity is 1.5h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 150:1;

[0114] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 2 MPa, the temperature is 165° C., and the liquid hourly space velocity is 1.5 h -1 ;

[0115] The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to be mixed with the first hydrogenation product, and then subjected to a second hydrogenation reaction; in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 0.5wt%.

[0116] The first catalyst is the same as the Pd-A / SiO2-Al2O3 catalyst provided in Example 1; the second catalyst is the same as the Pd / C catalyst provided in Example 1.

[0117] The composition of the α,α-dimethylbenzyl alcohol-containing raw material in step (1) is the same as that in Example 1.

[0118] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤50ppm, the production of bibenzyl is ≤150ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0119] Example 3

[0120] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0121] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the organic acid is p-toluenesulfonic acid; the amount of the organic acid added is 0.15wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 2.5MPa, the temperature is 125°C, and the liquid hourly space velocity is 2.5h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 250:1;

[0122] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 2.5 MPa, the temperature is 155° C., and the liquid hourly space velocity is 2.5 h -1 ;

[0123] The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to be mixed with the first hydrogenation product, and then subjected to a second hydrogenation reaction; in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 2wt%.

[0124] The first catalyst is the same as the Pd-A / SiO2-Al2O3 catalyst provided in Example 1; the second catalyst is the same as the Pd / C catalyst provided in Example 1.

[0125] The composition of the α,α-dimethylbenzyl alcohol-containing raw material in step (1) is the same as that in Example 1.

[0126] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤60ppm, the production of bibenzyl is ≤120ppm, the purity of cumene is ≥99.9%wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0127] Example 4

[0128] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0129] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the organic acid is p-toluenesulfonic acid; the amount of the organic acid added is 0.01wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 1.5MPa, the temperature is 140°C, and the liquid hourly space velocity is 1h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 100:1;

[0130] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 1.5 MPa, the temperature is 170°C, and the liquid hourly space velocity is 1h -1 ;

[0131] The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to mix with the first hydrogenation product, and then a second hydrogenation reaction is performed; in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 0.01wt%.

[0132] The first catalyst is the same as the Pd-A / SiO2-Al2O3 catalyst provided in Example 1; the second catalyst is the same as the Pd / C catalyst provided in Example 1.

[0133] The composition of the α,α-dimethylbenzyl alcohol-containing raw material in step (1) is the same as that in Example 1.

[0134] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤200 ppm, the bibenzyl production is ≤400 ppm, the purity of cumene is ≥99.9 wt %. In this embodiment, the conversion rate of α,α-dimethylbenzyl alcohol is ≥99%.

[0135] Example 5

[0136] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising the following steps:

[0137] (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the organic acid is p-toluenesulfonic acid; the amount of the organic acid added is 0.2 wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 3 MPa, the temperature is 120° C., and the liquid hourly space velocity is 3 h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is 300:1;

[0138] (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 3 MPa, the temperature is 150° C., and the liquid hourly space velocity is 3 h -1 ;

[0139] The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the obtained heavy component is returned to mix with the first hydrogenation product, and then subjected to a second hydrogenation reaction; in the mixture obtained by mixing the heavy component and the first hydrogenation product, the mass percentage of bibenzyl is 3wt%.

[0140] The first catalyst is the same as the Pd-A / SiO2-Al2O3 catalyst provided in Example 1; the second catalyst is the same as the Pd / C catalyst provided in Example 1.

[0141] The composition of the α,α-dimethylbenzyl alcohol-containing raw material in step (1) is the same as that in Example 1.

[0142] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤120ppm, the bibenzyl production is ≤300ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0143] Example 6

[0144] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, and the process parameters of the method are the same as those in Example 1.

[0145] The first catalyst used in the first hydrogenation reaction of this embodiment is Pd-A / SiO2-Al2O3, and the auxiliary agent A is B2O2. Taking the mass percentage of the first catalyst as 100%, the mass percentage of Pd is 0.05wt%, the mass percentage of A is 2wt%, and the mass percentage of the carrier SiO2-Al2O3 is 97.95wt%; SiO2 in the carrier SiO2-Al2O3 accounts for 30wt% of the total weight of the carrier.

[0146] The second catalyst is a Pd / C catalyst. Taking the mass percentage of the second catalyst as 100%, the mass percentage of Pd is 0.05wt%, and the mass percentage of the carrier C is 99.95wt%.

[0147] The α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 18wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

[0148] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤100 ppm, the bibenzyl production is ≤300 ppm, the purity of cumene is ≥99.9 wt %. In addition, the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0149] Example 7

[0150] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, and the process parameters of the method are the same as those in Example 1.

[0151] The first catalyst used in the first hydrogenation reaction of this embodiment is Pd-A / SiO2-Al2O3, and the auxiliary agent A is La2O3. Taking the mass percentage of the first catalyst as 100%, the mass percentage of Pd is 2wt%, the mass percentage of A is 4wt%, and the mass percentage of the carrier SiO2-Al2O3 is 94wt%; SiO2 in the carrier SiO2-Al2O3 accounts for 40wt% of the total weight of the carrier.

[0152] The second catalyst is a Pd / C catalyst. Taking the mass percentage of the second catalyst as 100%, the mass percentage of Pd is 2wt% and the mass percentage of the carrier C is 98wt%.

[0153] The α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 28wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

[0154] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤40ppm, the bibenzyl production is ≤100ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0155] Example 8

[0156] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, and the process parameters of the method are the same as those in Example 1.

[0157] The first catalyst used in the first hydrogenation reaction of this embodiment is Pd-A / SiO2-Al2O3, and the auxiliary agent A is MnO2. Taking the mass percentage of the first catalyst as 100%, the mass percentage of Pd is 0.5wt%, the mass percentage of A is 1wt%, and the mass percentage of the carrier SiO2-Al2O3 is 98.5wt%; SiO2 in the carrier SiO2-Al2O3 accounts for 65wt% of the total weight of the carrier.

[0158] The second catalyst is a Pd / C catalyst. Taking the mass percentage of the second catalyst as 100%, the mass percentage of Pd is 0.5wt% and the mass percentage of the carrier C is 99.5wt%.

[0159] The α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 25wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

[0160] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤50ppm, the production of bibenzyl is ≤200ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0161] Example 9

[0162] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, which is the same as that of Embodiment 1 except that p-toluenesulfonic acid is replaced by an equal mass of o-toluenesulfonic acid.

[0163] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤50ppm, the production of bibenzyl is ≤100ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0164] Example 10

[0165] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. The method is the same as that of Embodiment 1 except that p-toluenesulfonic acid is replaced by an equal mass of benzenesulfonic acid.

[0166] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≤50ppm, the production of bibenzyl is ≤100ppm, the purity of cumene is ≥99.9wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≥99%.

[0167] Embodiment 11

[0168] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. The method is the same as that of Embodiment 1 except that p-toluenesulfonic acid is replaced by an equal mass of oxalic acid.

[0169] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≥500ppm, the production of bibenzyl is ≥2000ppm, the purity of cumene is <99wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≤96.5%.

[0170] Example 12

[0171] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. The method is the same as that of Embodiment 1 except that p-toluenesulfonic acid is replaced by an equal mass of citric acid.

[0172] In the cumene product obtained in step (2) of this embodiment, the content of isopropylcyclohexane is ≥3500ppm, the production of bibenzyl is ≥300000ppm, the purity of cumene is <99wt%, and the conversion rate of α,α-dimethylbenzyl alcohol in this embodiment is ≤98.5%.

[0173] Embodiment 13

[0174] This embodiment provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol. The method is the same as that of Embodiment 1 except that the amount of organic acid added is 0.008 wt % of the raw material containing α,α-dimethylbenzyl alcohol.

[0175] Due to the reduced amount of organic acid added, the efficient conversion of α,α-dimethylbenzyl alcohol cannot be achieved under the 130°C condition provided in Example 1. In the cumene product obtained in step (2), the content of isopropylcyclohexane is less than 10ppm, the production of bibenzyl is ≤20ppm, and the purity of cumene is <92wt%. In addition, the conversion rate of α,α-dimethylbenzyl alcohol in this example is ≤88%.

[0176] Comparative Example 1

[0177] This comparative example provides a method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, which is the same as Example 1 except that p-toluenesulfonic acid is replaced by sulfuric acid of equal mass.

[0178] Sulfuric acid cannot be recovered by flash separation, and the presence of sulfuric acid affects the smooth progress of the second hydrogenation reaction. The impurity content in the obtained cumene product is relatively high, the content of isopropylcyclohexane is ≥300ppm, the production of bibenzyl is ≥10000ppm, and the purity of cumene is <98wt%. In addition, the conversion rate of α,α-dimethylbenzyl alcohol in this comparative example is ≤99%.

[0179] In summary, the present invention improves the acidity of the reaction system in the first hydrogenation reactor by arranging an organic acid addition device at the raw material inlet of the first hydrogenation reactor, thereby reducing the temperature required for the first hydrogenation reaction, not only reducing the unit consumption of isopropylbenzene, but also reducing the generation of by-product benzene ring hydrogenation products; the present invention realizes the recovery and utilization of bibenzyl by connecting the heavy component outlet with the feed inlet of the second hydrogenation reactor, converts bibenzyl into isopropylbenzene through the second hydrogenation reaction, and reduces the isopropylbenzene material consumption caused by the generation of by-products; the SiO2-Al2O3 in the first catalyst provided by the present invention has strong acidity, and the acidity of the first catalyst can be further improved by adding the auxiliary agent A, so that the first hydrogenation reactor can react at a lower hydrogenation temperature in combination with the organic acid provided by the organic acid addition device; the present invention improves the acidity of the reaction system of the first hydrogenation reaction by mixing the raw material containing α,α-dimethylbenzyl alcohol with the organic acid, so that the first hydrogenation reaction can be carried out at a lower temperature, which not only reduces the unit consumption of isopropylbenzene, but also avoids the problem of increased by-products caused by increased temperature.

[0180] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A device for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, characterized in that: The device comprises a first hydrogenation reactor, a flash separator, a second hydrogenation reactor and a deweighting device connected in sequence; An organic acid adding device is provided at the raw material inlet of the first hydrogenation reactor; A flash separator is arranged at the reactant outlet of the first hydrogenation reactor, and the liquid phase product obtained by the flash separator flows into the second hydrogenation reactor.

2. The device according to claim 1, characterized in that The heavy component outlet of the deweighting device is connected to the feed inlet of the second hydrogenation reactor.

3. The device according to claim 1 or 2, characterized in that: A first catalyst is arranged in the first hydrogenation reactor; the first catalyst is a Pd-A / SiO2-Al2O3 catalyst, wherein A is any one of B2O3, La2O3, CeO2 or MnO2 or a combination of at least two thereof.

4. The device according to claim 3, characterized in that Based on the mass percentage of the first catalyst being 100wt%, the mass percentage of Pd is 0.05-2wt%.

5. The device according to claim 3, characterized in that Based on the mass percentage of the first catalyst being 100wt%, the mass percentage of A is 1-4wt%.

6. The device according to claim 3, characterized in that Based on the mass percentage of the first catalyst being 100wt%, the mass percentage of the carrier SiO2-Al2O3 is 94-98.95wt%.

7. The device according to claim 6, characterized in that In the carrier SiO2-Al2O3, SiO2 accounts for 30-65wt% of the total mass of the carrier, and the balance is Al2O3.

8. The device according to claim 1, characterized in that The second hydrogenation reactor is provided with a second catalyst; the second catalyst is a Pd / C catalyst.

9. The device according to claim 8, characterized in that Based on the mass percentage of the second catalyst being 100 wt %, the mass percentage of Pd is 0.05-2 wt %, and the mass percentage of the carrier C is 98-99.95 wt %.

10. A method for preparing cumene by hydrogenolysis of α,α-dimethylbenzyl alcohol, characterized in that: The method comprises the following steps: (1) mixing a raw material containing α,α-dimethylbenzyl alcohol with an organic acid and hydrogen, performing a first hydrogenation reaction, and flash evaporating to separate water and the organic acid to obtain a first hydrogenation product; (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen and subjected to a second hydrogenation reaction. The second hydrogenation product is subjected to a de-heavy treatment to obtain an isopropylbenzene product.

11. The method according to claim 10, characterized in that The α,α-dimethylbenzyl alcohol-containing raw material in step (1) comprises: 18-28wt% of α,α-dimethylbenzyl alcohol, ≤0.05wt% of propylene oxide, ≤0.3wt% of cumene hydroperoxide, ≤0.2wt% of phenol, and the balance is cumene.

12. The method according to claim 10, characterized in that The organic acid in step (1) includes any one of benzenesulfonic acid, o-toluenesulfonic acid or p-toluenesulfonic acid, or a combination of at least two thereof.

13. The method according to claim 10, characterized in that The amount of the organic acid added in step (1) is 0.01-0.2 wt % of the raw material containing α,α-dimethylbenzyl alcohol.

14. The method according to claim 10, characterized in that The catalyst used in the first hydrogenation reaction in step (1) is the first catalyst.

15. The method according to claim 10, characterized in that The gauge pressure of the first hydrogenation reaction in step (1) is 1.5-3 MPa and the temperature is 120-140°C.

16. The method according to claim 10, characterized in that The liquid hourly space velocity of the first hydrogenation reaction in step (1) is 1-3h -1 .

17. The method according to claim 10, characterized in that Step (1) The volume ratio of hydrogen to α,α-dimethylbenzyl alcohol in the first hydrogenation reaction is (100-300):

1.

18. The method according to claim 10, characterized in that The catalyst used in the second hydrogenation reaction in step (2) is a second catalyst.

19. The method according to claim 10, characterized in that Step (2) The gauge pressure of the second hydrogenation reaction is 1.5-3 MPa and the temperature is 150-170°C.

20. The method according to claim 10, characterized in that Step (2) The liquid hourly space velocity of the second hydrogenation reaction is 1-3h -1 .

21. The method according to claim 10, characterized in that The light component obtained by the de-heavy treatment in step (2) is an isopropylbenzene product, and the heavy component obtained is returned to mix with the first hydrogenation product, and then a second hydrogenation reaction is carried out.

22. The method according to claim 21, characterized in that In the mixture obtained by mixing the heavy component with the first hydrogenation product, the mass percentage of bibenzyl is 0.01-3wt%.

23. The method according to claim 22, characterized in that In the mixture obtained by mixing the heavy component with the first hydrogenation product, the mass percentage of bibenzyl is 0.1-1.5wt%.

24. The method according to claim 10, characterized in that The method comprises the following steps: (1) A raw material containing α,α-dimethylbenzyl alcohol is mixed with an organic acid and hydrogen, a first hydrogenation reaction is performed using a first catalyst, and water and the organic acid are separated by flash evaporation to obtain a first hydrogenation product; the amount of the organic acid added is 0.01-0.2wt% of the raw material containing α,α-dimethylbenzyl alcohol; the gauge pressure of the first hydrogenation reaction is 1.5-3MPa, the temperature is 120-140°C, and the liquid hourly space velocity is 1-3h -1 , the volume ratio of hydrogen to α,α-dimethylbenzyl alcohol is (100-300):1; (2) The first hydrogenation product obtained in step (1) is mixed with hydrogen, and a second hydrogenation reaction is carried out using a second catalyst. The second hydrogenation product is subjected to a de-weighting treatment to obtain an isopropylbenzene product; the gauge pressure of the second hydrogenation reaction is 1.5-3 MPa, the temperature is 150-170°C, and the liquid hourly space velocity is 1-3 h -1 .

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