Method for preparing cumene by hydrogenation of alpha, alpha-dimethyl benzyl alcohol-containing hydrocarbon material and application thereof

Abstract

The invention discloses a method for preparing cumene through hydrogenation of a hydrocarbon material containing alpha, alpha-dimethyl benzyl alcohol and application of the cumene, and the method comprises the following steps: mixing the hydrocarbon material containing alpha, alpha-dimethyl benzyl alcohol with hydrogen, and then sequentially introducing the mixture into a first catalyst bed layer and a second catalyst bed layer which are connected in series for reaction, the first catalyst bed layer is filled with a first catalyst, the second catalyst bed layer is filled with a second catalyst, the first catalyst and the second catalyst respectively comprise a carrier I and a carrier II, and the average pore size of the carrier I is larger than that of the carrier II. According to the method, the conversion rate and selectivity of the hydrogenation reaction of the alpha, alpha-dimethyl benzyl alcohol hydrocarbon material can be improved, and long-period stable operation can be ensured.

Description

Technical Field

[0001] This invention belongs to the field of cumene preparation, and particularly relates to the preparation of cumene by hydrogenation of α,α-dimethylbenzyl alcohol and its applications. Background Technology

[0002] Propylene oxide (PO) is an important organic chemical raw material, mainly used in the production of polyether polyols, propylene glycol, and propylene glycol ethers, with polyether polyols accounting for approximately 70% of consumption. The CHP (cumene hydroperoxide) process for producing PO is a relatively safe and environmentally friendly production route. The hydrogenolysis of α,α-dimethylbenzyl alcohol to cumene is a crucial reaction unit connecting upstream and downstream processes; therefore, the activity and stability of the hydrogenolysis catalyst are essential for improving the technological advancement and economic efficiency of CHPPO.

[0003] Dimethylbenzyl alcohol can be dehydrated to AMS via acid catalysis, and then hydrogenated to cumene using Pd / Al2O3 catalysis. This latter reaction process is widely used in phenol-acetone plants. Sumitomo Chemical uses a combination of Al2O3 dehydration catalyst and Pd-based hydrogenation catalyst to convert dimethylbenzyl alcohol to cumene. Sinopec Shanghai Petrochemical Research Institute developed an acid-metal bifunctional Pd / Al2O3 catalyst to couple the dehydration and hydrogenation processes. Japanese patents JP2001-270880A and 2003-081886A reported techniques for the hydrogenolysis of α,α-dimethylbenzyl alcohol to cumene using copper-based catalysts. However, because copper catalysts have high hydrogen dissociation activation energies, the reaction needs to be carried out at relatively high temperatures, which easily triggers side reactions such as polymerization, affecting the selectivity of cumene and the stability of the catalyst. US Patent 7442843B2 discloses a process for producing cumene. This technology uses a palladium-based catalyst and α,α-dimethylbenzyl alcohol and hydrogen as raw materials to produce cumene through hydrogenolysis or dehydration hydrogenation. The hydrogen used contains 0.1-10% CO, which can significantly improve the conversion rate of dimethylbenzyl alcohol and the selectivity of cumene.

[0004] In existing technologies, there are more studies on improving the activity and selectivity of α,α-dimethylbenzyl alcohol hydrogenolysis by modifying catalysts, while there are fewer studies on improving the conversion rate and selectivity of the reaction by creating catalysts and adopting new processes, as well as maintaining high conversion rate and high selectivity under long-term operation. Summary of the Invention

[0005] To overcome the problems existing in the prior art, the present invention provides a method for preparing cumene by hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons and its application. The method can improve the conversion rate and selectivity of the hydrogenation reaction of α,α-dimethylbenzyl alcohol hydrocarbons and ensure long-term stable operation.

[0006] One objective of this invention is to provide a method for preparing cumene by hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons, comprising: mixing the α,α-dimethylbenzyl alcohol hydrocarbon with hydrogen gas and then sequentially passing it into a first catalyst bed and a second catalyst bed connected in series for reaction, wherein a first catalyst is loaded on the first catalyst bed and a second catalyst is loaded on the second catalyst bed, the first catalyst and the second catalyst respectively comprising a support I and a support II, wherein the average pore size of the support I is larger than the average pore size of the support II.

[0007] The first catalyst includes support I, and the second catalyst includes support II.

[0008] In a preferred embodiment, the first catalyst further comprises an active component I supported on a support I, wherein the active component I is selected from at least one of palladium and / or its oxides, nickel and / or its oxides, and copper and / or its oxides.

[0009] In a further preferred embodiment, the content of active component I in the first catalyst is 0.06 g / L to 30 g / L, preferably 0.2 g / L to 10 g / L, for example 0.06 g / L, 0.1 g / L, 0.5 g / L, 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L or 30 g / L.

[0010] In a preferred embodiment, the second catalyst further comprises an active component II supported on a support II, and optionally a cooperating metal and / or its oxide supported on the support II; preferably, the active component II is selected from at least one of palladium and / or its oxide, nickel and / or its oxide; more preferably, the cooperating metal is selected from at least one of cerium, lanthanum, copper, cobalt, tin and molybdenum.

[0011] In a further preferred embodiment, in the second catalyst, the content of the active component II is 0.06 g / L to 30 g / L, and the content of the auxiliary metal and / or its oxide is 0.0006 g / L to 1.0 g / L.

[0012] For example, in the second catalyst, the content of the active component II is 0.06 g / L, 0.1 g / L, 0.5 g / L, 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L or 30 g / L, and the content of the auxiliary metal and / or its oxide is 0.0006 g / L, 0.001 g / L, 0.005 g / L, 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.4 g / L, 0.6 g / L, 0.8 g / L or 1.0 g / L.

[0013] In a further preferred embodiment, in the second catalyst, the content of the active component II is 0.1 g / L to 10 g / L, and the content of the auxiliary metal and / or its oxide is 0.01 g / L to 0.5 g / L.

[0014] In a preferred embodiment, the second catalyst may further optionally contain phosphorus and / or its oxides.

[0015] In a further preferred embodiment, based on the carrier II, the content of phosphorus and / or its oxides is 0.5 to 10 wt%, preferably 1.0 to 6.0 wt%, for example 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%.

[0016] In the first and second catalysts, the support is not particularly limited and can be any material commonly used in the art. For example, but not limited to, the support may include at least one selected from alumina, silicon oxide, and activated carbon, with alumina being preferred. The source of the active component is not particularly limited. Taking palladium metal as an example, for example, but not limited to at least one of palladium chloride, palladium nitrate, chloropalladium acid, etc. The source of the auxiliary metal is not particularly limited. For example, but not limited to at least one of auxiliary metal chloride, auxiliary metal nitrate compound, auxiliary metal acetate compound, etc.

[0017] In a preferred embodiment, the carrier I has an average pore size greater than 16 nm and preferably less than 40 nm, and a specific surface area not exceeding 120 m². 2 / g and preferably greater than 50m 2 / g.

[0018] For example, the carrier I has an average pore size of 18nm, 20nm, 22nm, 25nm, 28nm, 30nm, 32nm, 35nm, 38nm or 40nm and a specific surface area of ​​52m². 2 / g、55m 2 / g、60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g, 100m 2 / g、110m 2 / g or 120m 2 / g.

[0019] In a further preferred embodiment, the carrier I has an average pore size greater than 20 nm and preferably less than 35 nm, and a specific surface area not exceeding 100 m². 2 / g and preferably greater than 50m 2 / g.

[0020] The average pore size and specific surface area of ​​carrier I were obtained by nitrogen adsorption test.

[0021] In a preferred embodiment, the carrier II has an average pore size of 8–20 nm and a specific surface area of ​​90–200 m². 2 / g.

[0022] For example, the carrier II has an average pore size of 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, or 20 nm and a specific surface area of ​​90 m². 2 / g, 100m 2 / g, 120m 2 / g, 140m 2 / g, 160m 2 / g、180m 2 / g or 200m 2 / g.

[0023] In a further preferred embodiment, the carrier II has an average pore size of 12–18 nm and a specific surface area of ​​110–180 m². 2 / g.

[0024] The average pore size and specific surface area of ​​carrier II were obtained by nitrogen adsorption test.

[0025] In a preferred embodiment, the catalyst loading amount of the first catalyst bed is less than that of the second catalyst bed.

[0026] In a further preferred embodiment, the volume ratio of the catalyst loading amount of the first catalyst bed to the catalyst loading amount of the second catalyst bed is 1:(2-8), preferably 1:(3-6), more preferably 1:(3-5), for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 or 1:8.

[0027] In a preferred embodiment, the output of the second catalyst bed is divided into three streams: the first stream is purchased externally as a product, the second stream is recycled back to the first catalyst bed, and the third stream is recycled back to the second catalyst bed.

[0028] In a further preferred embodiment, the circulation ratio of the first catalyst bed is less than or equal to 3 (preferably greater than 0), for example, 3, 2.5, 2, 1.5, 1 or 0.5.

[0029] Wherein, the (volume) circulation ratio of the first catalyst bed refers to the ratio of the volume of liquid phase returning to the inlet of the first catalyst bed to the volume of liquid phase feedstock of the first catalyst bed.

[0030] In a further preferred embodiment, the circulation ratio of the second catalyst bed is greater than or equal to 1, preferably 1 to 10, for example 1, 2, 4, 6, 8 or 10.

[0031] The (volume) circulation ratio of the second catalyst bed refers to the ratio of the volume of liquid phase returning to the inlet of the second catalyst bed to the volume of liquid phase feedstock into the second catalyst bed.

[0032] In a preferred embodiment, the inlet temperature of the first catalyst bed is controlled to be 100–200°C, the reaction pressure to be 0.01–4.0 MPa, and the fresh oil volume hourly space velocity to be 1–10 h⁻¹. -1 Fresh oil refers to materials containing α,α-dimethylbenzyl alcohol hydrocarbons, excluding the circulating liquid phase of the first bed.

[0033] For example, the inlet temperature of the first catalyst bed can be controlled at 100℃, 120℃, 140℃, 160℃, 180℃, or 200℃, the reaction pressure at 0.01MPa, 0.05MPa, 0.1MPa, 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, or 4.0MPa, and the fresh oil liquid phase volume hourly space velocity at 1 h⁻¹. -1 2h -1 3h -1 4h -1 5h -1 6h -1 7h -1 8h -1 9h -1 or 10h -1 .

[0034] After extensive experimental research, the inventors discovered that using a first catalyst with a larger average pore size in conjunction with a first catalyst bed at a temperature within the aforementioned range can significantly improve the long-term stability and hydrogenation selectivity of the hydrogenation process.

[0035] In a further preferred embodiment, the inlet temperature of the first catalyst bed is controlled at 130–170°C (preferably 135–160°C), the reaction pressure is controlled at 0.5–3.0 MPa, and the fresh oil liquid phase volume hourly space velocity is controlled at 2–6 h⁻¹. -1 .

[0036] In a preferred embodiment, the reaction pressure of the second catalyst bed is controlled to be 0.01 to 4.0 MPa.

[0037] For example, the reaction pressure of the second catalyst bed can be controlled to be 0.01 MPa, 0.05 MPa, 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa or 4.0 MPa.

[0038] In a further preferred embodiment, the reaction pressure of the second catalyst bed is controlled to be 0.5 to 3.0 MPa.

[0039] In a preferred embodiment, the volume ratio of hydrogen entering the first catalyst bed to α,α-dimethylbenzyl alcohol hydrocarbon material (i.e., fresh oil) entering the first catalyst bed is greater than or equal to 150, preferably 200 to 500, for example 160, 180, 200, 250, 300, 350, 400, 450 or 500.

[0040] In a preferred embodiment, the α,α-dimethylbenzyl alcohol hydrocarbon contains α,α-dimethylbenzyl alcohol, an optional inert solvent, and an optional impurity, wherein the impurity is methylstyrene and / or acetophenone.

[0041] The inert solvent must be substantially inactive to the reactants and products, such as long-chain alkanes (octane, dodecane) and aromatic monocyclic aromatic hydrocarbons (benzene, toluene, ethylbenzene, n-propylbenzene, n-butane, isopropylbenzene), for example, isopropylbenzene.

[0042] In a further preferred embodiment, the content of α,α-dimethylbenzyl alcohol in the α,α-dimethylbenzyl alcohol hydrocarbon material is 0 to 100 wt% and does not contain 0, preferably 0.01 to 99.999 wt%, for example 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%.

[0043] The α,α-dimethylbenzyl alcohol hydrocarbon material described in this invention can be derived from the bottom liquid of the tower after separating propylene oxide in the process of producing propylene oxide by the hydroperoxide isopropylbenzene method, or obtained by the reduction of hydroperoxide isopropylbenzene.

[0044] The hydrogenation method described in this invention can effectively improve the conversion rate of α,α-dimethylbenzyl alcohol per unit volume of catalyst, significantly improving catalyst stability while increasing cumene selectivity. For example, under the conditions of a first catalyst bed inlet temperature of 140°C and a pressure of 2.0 MPa, the conversion rate of α,α-dimethylbenzyl alcohol is greater than 99.9%, the selectivity of cumene is greater than 99.8%, and the catalyst can operate stably continuously for 200 hours, achieving good technical results and possessing broad industrial application value.

[0045] A second objective of this invention is to provide the application of the method described in one objective of this invention in the preparation of propylene oxide.

[0046] A third objective of this invention is to provide a method for preparing propylene oxide, comprising:

[0047] (1) Oxidize the material containing cumene to obtain the material containing cumene peroxide;

[0048] (2) The propylene stream containing hydrogen peroxide isopropylbenzene is reacted with the propylene, and the propylene oxide and α,α-dimethylbenzyl alcohol hydrocarbons are obtained by distillation separation.

[0049] (3) The α,α-dimethylbenzyl alcohol hydrocarbon material is hydrogenated using the method described in one of the objectives of this invention to obtain cumene.

[0050] The oxidation treatment in step (1) and the epoxidation process in step (2) can be performed using existing technologies.

[0051] 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.

[0052] Compared with the prior art, the present invention has the following beneficial effects: it can improve the conversion rate and selectivity of hydrogenation reaction of α,α-dimethylbenzyl alcohol hydrocarbons and ensure long-term stable operation, especially improving the high conversion rate and high selectivity maintained under long-term operation. Detailed Implementation

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The main components of the raw materials used in the experiment are shown in Table 1.

[0058] Table 1:

[0059] Raw material composition weight composition (wt%) Cumene 57.1 n-Propane 0.12 Methylstyrene 0.13 Acetophenone 0.65 α,α-Dimethylbenzyl alcohol 41

[0060] in:

[0061] α,α-Dimethylbenzyl alcohol conversion (%) = (W1) 0 -W1 t ) / W1 0 ×100%;

[0062] Cumene selectivity (%) = (W2) t –W2 0 ) / (W1 0 -W1 t )×100%;

[0063] W1 0 : Mass content of α,α-dimethylbenzyl alcohol in the raw material; W1 t : Mass content of α,α-dimethylbenzyl alcohol in the hydrogenation product; W2 0 : Mass content of cumene in raw materials; W2 t Mass content of cumene in the hydrogenation product.

[0064] The physical properties of the catalytic material (such as specific surface area, pore size, and pore volume) were analyzed using nitrogen physical adsorption (ASAP2020M, Micromeritics). Before analysis, the sample was degassed under vacuum at 300℃ for 3 hours to remove adsorbed impurities and moisture. The nitrogen adsorption-desorption isotherms were then analyzed in liquid nitrogen (-196℃). The specific surface area was calculated using the Brunauer-Emmett-Teller (BET) method, and the pore structure characteristics were analyzed using the Barret-Joyner-Halenda (BJH) method. The pore volume (Vp) of the sample was obtained from the volume of nitrogen adsorbed when P / P0 was 0.95.

[0065] In the embodiment: the reactor inlet temperature is the inlet temperature of the first catalyst bed, the reactor pressure is the pressure of the first catalyst bed and the second catalyst bed, and the hydrogen / fresh oil volume ratio is the volume ratio of hydrogen to fresh oil in the first catalyst bed.

[0066]

Example 1

[0067] a. Preparation of the first catalyst for the first catalyst bed

[0068] A 75 ml aqueous solution of palladium nitrate-nitric acid containing 0.3 g palladium was sprayed onto a 100 ml alumina support (Φ1.5 mm * 3) with an average pore size of 26 nm and a specific surface area of ​​82 m² using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 450°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The first catalyst was obtained.

[0069] b. The second catalyst bed is prepared using the second catalyst.

[0070] A 70 ml aqueous solution of palladium nitrate and copper nitrate containing 0.2 g palladium and 0.05 g copper was sprayed onto 100 ml of Φ2.5 mm * 3 alumina microspheres (containing 3 wt% phosphorus, with an average N2- adsorption pore size of 12 nm and a specific surface area of ​​142 m²) using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The second catalyst was obtained.

[0071] A first catalyst bed and a second catalyst bed are packed in a reactor. Both the first and second catalyst beds are topped with ceramic ball layers. Hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons is performed in a continuous top-in, bottom-out manner. The material first passes through the first catalyst bed, which is filled with the first catalyst, and then through the second catalyst bed, which is filled with the second catalyst. The volume ratio of the catalysts in the first to the second catalyst beds is 1:3. The operating conditions of the catalyst beds are as follows:

[0072] Reactor inlet temperature: 140℃

[0073] Reactor pressure: 2.0 MPa

[0074] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0075] First bed liquid phase circulation ratio: 2

[0076] Hydrogen / fresh oil volume ratio: 300

[0077] Second bed liquid phase circulation ratio: 3

[0078] The average results of the 200-hour evaluation are shown in Table 2.

[0079]

Example 2

[0080] a. Preparation of the first catalyst for the first catalyst bed

[0081] A 75 ml aqueous solution of palladium nitrate-nitric acid containing 0.3 g palladium was sprayed onto a 100 ml alumina support (Φ1.5 mm * 3) with an average pore size of 32 nm and a specific surface area of ​​65 m² using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 450°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The first catalyst was obtained.

[0082] b. The second catalyst bed is prepared using the second catalyst.

[0083] A 70 ml aqueous solution of palladium nitrate and copper nitrate containing 0.2 g palladium and 0.05 g copper was sprayed onto 100 ml of Φ2.5 mm * 3 alumina microspheres (containing 3 wt% phosphorus, with an average N2- adsorption pore size of 14 nm and a specific surface area of ​​136 m²) using an equal-volume impregnation method. 2On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The second catalyst was obtained.

[0084] A first catalyst bed and a second catalyst bed are packed in a reactor. Both the first and second catalyst beds are topped with ceramic ball layers. Hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons is performed in a continuous top-in, bottom-out manner. The material first passes through the first catalyst bed, which is filled with the first catalyst, and then through the second catalyst bed, which is filled with the second catalyst. The volume ratio of the catalysts in the first to the second catalyst beds is 1:3. The operating conditions of the catalyst beds are as follows:

[0085] Reactor inlet temperature: 140℃

[0086] Reactor pressure: 2.0 MPa

[0087] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0088] First bed liquid phase circulation ratio: 2

[0089] Hydrogen / fresh oil volume ratio: 300

[0090] Second bed liquid phase circulation ratio: 3

[0091] The average results of the 200-hour evaluation are shown in Table 2.

[0092]

Example 3

[0093] a. Preparation of the first catalyst for the first catalyst bed

[0094] A 75 ml aqueous solution of palladium nitrate-nitric acid containing 0.3 g palladium was sprayed onto a 100 ml alumina support (Φ1.5 mm * 3) with an average pore size of 22 nm and a specific surface area of ​​102 m² using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 450°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The first catalyst was obtained.

[0095] b. The second catalyst bed is prepared using the second catalyst.

[0096] A 70 ml aqueous solution of palladium nitrate and copper nitrate containing 0.2 g palladium and 0.05 g copper was sprayed onto 100 ml of Φ2.5 mm * 3 alumina microspheres (containing 3 wt% phosphorus, with an average N2- adsorption pore size of 14 nm and a specific surface area of ​​136 m²) using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The second catalyst was obtained.

[0097] A first catalyst bed and a second catalyst bed are packed in a reactor. Both the first and second catalyst beds are topped with ceramic ball layers. Hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons is performed in a continuous top-in, bottom-out manner. The material first passes through the first catalyst bed, which is filled with the first catalyst, and then through the second catalyst bed, which is filled with the second catalyst. The volume ratio of the catalysts in the first to the second catalyst beds is 1:3. The operating conditions of the catalyst beds are as follows:

[0098] Reactor inlet temperature: 140℃

[0099] Reactor pressure: 2.0 MPa

[0100] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0101] First bed liquid phase circulation ratio: 2

[0102] Hydrogen / fresh oil volume ratio: 300

[0103] Second bed liquid phase circulation ratio: 3

[0104] The average results of the 200-hour evaluation are shown in Table 2.

[0105]

Example 4

[0106] a. Preparation of the first catalyst for the first catalyst bed

[0107] A 75 ml aqueous solution of palladium nitrate-nitric acid containing 0.3 g palladium was sprayed onto a 100 ml alumina support (Φ1.5 mm * 3) with an average pore size of 32 nm and a specific surface area of ​​65 m² using an equal-volume impregnation method. 2On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 450°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The first catalyst was obtained.

[0108] b. The second catalyst bed is prepared using the second catalyst.

[0109] A 70 ml aqueous solution of palladium nitrate and copper nitrate containing 0.2 g palladium and 0.05 g copper was sprayed onto 100 ml of Φ2.5 mm * 3 alumina microspheres (containing 3 wt% phosphorus, with an average N2- adsorption pore size of 16 nm and a specific surface area of ​​112 m²) using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The second catalyst was obtained.

[0110] A first catalyst bed and a second catalyst bed are packed in a reactor. Both the first and second catalyst beds are topped with ceramic ball layers. Hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons is performed in a continuous top-in, bottom-out manner. The material first passes through the first catalyst bed, which is filled with the first catalyst, and then through the second catalyst bed, which is filled with the second catalyst. The volume ratio of the catalysts in the first to the second catalyst beds is 1:3. The operating conditions of the catalyst beds are as follows:

[0111] Reactor inlet temperature: 150℃

[0112] Reactor pressure: 2.0 MPa

[0113] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0114] First bed liquid phase circulation ratio: 2

[0115] Hydrogen / fresh oil volume ratio: 300

[0116] Second bed liquid phase circulation ratio: 3

[0117] The average results of the 200-hour evaluation are shown in Table 2.

[0118]

Example 5

[0119] a. Preparation of the first catalyst for the first catalyst bed

[0120] A 75 ml aqueous solution of palladium nitrate-nitric acid containing 0.3 g palladium was sprayed onto a 100 ml alumina support (Φ1.5 mm * 3) with an average pore size of 32 nm and a specific surface area of ​​65 m² using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 450°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The first catalyst was obtained.

[0121] b. The second catalyst bed is prepared using the second catalyst.

[0122] A 70 ml aqueous solution of palladium nitrate and copper nitrate containing 0.2 g palladium and 0.05 g copper was sprayed onto 100 ml of Φ2.5 mm * 3 alumina microspheres (containing 3 wt% phosphorus, with an average N2- adsorption pore size of 16 nm and a specific surface area of ​​112 m²) using an equal-volume impregnation method. 2 On a plate (g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium oxide-based catalyst precursor I. The above-mentioned palladium oxide-based catalyst precursor I is then reduced with hydrogen gas for 4 hours at a reduction temperature of 130°C and a hydrogen volume hourly space velocity of 100 h⁻¹. -1 The second catalyst was obtained.

[0123] A first catalyst bed and a second catalyst bed are packed in a reactor. Both the first and second catalyst beds are topped with ceramic ball layers. Hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons is performed in a continuous top-in, bottom-out manner. The material first passes through the first catalyst bed, which is filled with the first catalyst, and then through the second catalyst bed, which is filled with the second catalyst. The volume ratio of the catalysts in the first to the second catalyst beds is 1:3. The operating conditions of the catalyst beds are as follows:

[0124] Reactor inlet temperature: 160℃

[0125] Reactor pressure: 2.0 MPa

[0126] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0127] First bed liquid phase circulation ratio: 3

[0128] Hydrogen / fresh oil volume ratio: 300

[0129] Second bed liquid phase circulation ratio: 3

[0130] The average results of the 200-hour evaluation are shown in Table 2.

[0131]

Example 6

[0132] By simply changing the composition of the second catalyst bed to that of the second catalyst, 70 ml of a mixed aqueous solution of palladium nitrate and copper nitrate containing 0.3 g of palladium and 0.03 g of copper was sprayed onto 100 ml of alumina microspheres with a shape of Φ2.5 mm * 3 (containing 5 wt% phosphorus, with an average N2- adsorption pore size of 16 nm and a specific surface area of ​​112 m²) using an equal-volume impregnation method. 2 After the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium-based catalyst precursor I in oxide state. The rest is the same as in Example 5.

[0133]

Example 7

[0134] By simply changing the composition of the second catalyst bed and using a second catalyst, 70 ml of a mixed aqueous solution of palladium nitrate and copper nitrate containing 0.4 g of palladium and 0.03 g of copper was sprayed onto 100 ml of alumina microspheres with a shape of Φ2.5 mm * 3 (containing 6 wt% phosphorus, with an average N2- adsorption pore size of 16 nm and a specific surface area of ​​112 m²). 2 On / g), after the liquid has fully impregnated the alumina support, the impregnated alumina support is dried at 110°C for 8 hours and calcined at 550°C for 4 hours to obtain palladium-based catalyst precursor I in oxide state. The rest is the same as in Example 5.

[0135]

Example 8

[0136] The only change was that the volume ratio of the catalyst loading in the first catalyst bed to the second catalyst bed was 1:5, and the rest was the same as in Example 5.

[0137]

Example 9

[0138] The only change was to the operating conditions of the catalyst bed; the rest was the same as in Example 5.

[0139] Reactor inlet temperature: 160℃

[0140] Reactor pressure: 2.0 MPa

[0141] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0142] First bed liquid phase circulation ratio: 1

[0143] Hydrogen / fresh oil volume ratio: 300

[0144] Second bed liquid phase circulation ratio: 3

[0145]

Example 10

[0146] The only change was to the operating conditions of the catalyst bed; the rest was the same as in Example 5.

[0147] Reactor inlet temperature: 160℃

[0148] Reactor pressure: 2.0 MPa

[0149] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0150] First bed liquid phase circulation ratio: 3

[0151] Hydrogen / fresh oil volume ratio: 300

[0152] Second bed liquid phase circulation ratio: 5

[0153]

Example 11

[0154] The only change was to the operating conditions of the catalyst bed; the rest was the same as in Example 5.

[0155] Reactor inlet temperature: 160℃

[0156] Reactor pressure: 2.0 MPa

[0157] Reactor inlet fresh oil volumetric space velocity: 3h -1

[0158] First bed liquid phase circulation ratio: 3

[0159] Hydrogen / fresh oil volume ratio: 300

[0160] Second bed liquid phase circulation ratio: 8

[0161] Comparative Example 1

[0162] The process of Example 1 was repeated, except that the same support was used when preparing the second catalyst as when preparing the first catalyst, and other conditions remained unchanged.

[0163] Comparative Example 2

[0164] The process of Example 1 was repeated, except that the same support was used in the preparation of the first catalyst as in the preparation of the second catalyst, and other conditions remained unchanged.

[0165] Table 2: Results of hydrogenation

[0166]

[0167] 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 by hydrogenation of α,α-dimethylbenzyl alcohol hydrocarbons, comprising: A mixture of α,α-dimethylbenzyl alcohol hydrocarbons and hydrogen is sequentially introduced into a first catalyst bed and a second catalyst bed connected in series for reaction. The first catalyst bed is loaded with a first catalyst, and the second catalyst bed is loaded with a second catalyst. The first catalyst and the second catalyst are respectively supported by a support I and a support II, wherein the average pore size of the support I is larger than that of the support II.

2. The method according to claim 1, characterized in that, The first catalyst further includes an active component I supported on a support I, wherein the active component I is selected from at least one of palladium and / or its oxides, nickel and / or its oxides, and copper and / or its oxides; Preferably, in the first catalyst, the content of active component I is 0.06 g / L to 30 g / L, more preferably 0.2 g / L to 10 g / L.

3. The method according to claim 1, characterized in that, The second catalyst further comprises an active component II supported on a support II, and optionally a cooperating metal and / or its oxide supported on a support II; preferably, the active component II is selected from at least one of palladium and / or its oxide, nickel and / or its oxide; more preferably, the cooperating metal is selected from at least one of cerium, lanthanum, copper, cobalt, tin and molybdenum; Preferably, in the second catalyst, the content of the active component II is 0.06 g / L to 30 g / L, more preferably 0.1 g / L to 10 g / L; and the content of the auxiliary metal and / or its oxide is 0.0006 g / L to 1.0 g / L, more preferably 0.01 g / L to 0.5 g / L.

4. The method according to claim 3, characterized in that, The second catalyst optionally further contains phosphorus and / or its oxides; preferably, based on the support II, the content of phosphorus and / or its oxides is 0.5 to 10.0 wt%, more preferably 1.0 to 6.0 wt%.

5. The method according to claim 1, characterized in that, The average pore size of the carrier I is greater than 16 nm, preferably greater than 20 nm; and / or, The specific surface area of ​​carrier I is no higher than 120m². 2 / g, preferably not exceeding 100m 2 / g.

6. The method according to claim 1, characterized in that, The average pore size of the carrier II is 8–20 nm, preferably 12–18 nm; and / or, The specific surface area of ​​the carrier II is 90–200 m². 2 / g, preferably 110-180m 2 / g.

7. The method according to claim 1, characterized in that, The catalyst loading amount in the first catalyst bed is less than that in the second catalyst bed; Preferably, the volume ratio of the catalyst loading amount of the first catalyst bed to the catalyst loading amount of the second catalyst bed is 1:(2-8), and more preferably 1:(3-6).

8. The method according to claim 1, characterized in that, The output of the second catalyst bed is divided into three streams: the first stream is purchased externally as a product, the second stream is recycled back to the first catalyst bed, and the third stream is recycled back to the second catalyst bed. Preferably, the circulation ratio of the first catalyst bed is less than or equal to 3; Preferably, the circulation ratio of the second catalyst bed is greater than or equal to 1, and more preferably 1 to 10.

9. The method according to any one of claims 1 to 8, characterized in that, The inlet temperature of the first catalyst bed is controlled at 100–200℃, the reaction pressure at 0.01–4.0 MPa, and the fresh oil volume hourly space velocity at 1–10 h⁻¹. -1 Preferably, the inlet temperature of the first catalyst bed is controlled at 130–170°C, the reaction pressure at 0.5–3.0 MPa, and the fresh oil volume hourly space velocity at 2–6 h⁻¹. -1 ; and / or, The volume ratio of hydrogen entering the first catalyst bed to the α,α-dimethylbenzyl alcohol-containing hydrocarbon material entering the first catalyst bed is greater than or equal to 150, preferably 200 to 500; and / or, The reaction pressure of the second catalyst bed is controlled to be 0.01 to 4.0 MPa, preferably 0.5 to 3.0 MPa.

10. The method according to claim 1, characterized in that, The α,α-dimethylbenzyl alcohol hydrocarbon material contains α,α-dimethylbenzyl alcohol, optional inert solvent, and optional impurities; Preferably, the content of α,α-dimethylbenzyl alcohol in the α,α-dimethylbenzyl alcohol hydrocarbon material is 0 to 100 wt% and does not contain 0, preferably 0.01 to 99.999 wt%.

11. The application of the method according to any one of claims 1 to 10 in the preparation of propylene oxide.

12. A method for preparing propylene oxide, comprising: (1) Oxidize the material containing cumene to obtain the material containing cumene peroxide; (2) The propylene stream containing hydrogen peroxide isopropylbenzene is reacted with the propylene, and the propylene oxide and α,α-dimethylbenzyl alcohol hydrocarbons are obtained by distillation separation. (3) Hydrogenation of the α,α-dimethylbenzyl alcohol hydrocarbon material by any one of the methods described in claims 1 to 10 to obtain cumene.

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