Alpha, alpha-dimethyl benzyl alcohol hydrogenolysis method

Abstract

The invention relates to the technical field of isopropyl benzene preparation, in particular to an alpha, alpha-dimethyl benzyl alcohol hydrogenolysis method which comprises the following steps: in the presence of a hydrogenolysis catalyst, carrying out hydrogenolysis reaction on a hydrocarbon material containing alpha, alpha-dimethyl benzyl alcohol and hydrogen to obtain a product flow containing isopropyl benzene; wherein the product flow contains alpha-methylstyrene, and when the content of the alpha-methylstyrene in the product flow is not higher than 1.0 wt%, the hydrogenolysis catalyst subjected to the hydrogenolysis reaction is regenerated to obtain a regenerated catalyst. According to the method disclosed by the invention, the catalyst is regenerated at a specific time, so that a better regeneration effect is achieved, the service life of the catalyst is prolonged, then the regenerated catalyst is continuously used for hydrogenolysis reaction, and a relatively high dimethyl benzyl alcohol conversion rate can be ensured.

Description

Technical Field

[0001] This invention relates to the field of cumene preparation technology, and more specifically to a method for hydrogenolysis of α,α-dimethylbenzyl alcohol. Background Technology

[0002] Propylene oxide (PO) is an important organic chemical raw material. The cumene hydroperoxide (CHP) process for producing propylene oxide is a green PO production technology with no byproducts. It includes reaction units such as cumene oxidation, propylene epoxidation, and α,α-dimethylbenzyl alcohol hydrogenolysis (DMBA). The propylene epoxidation unit produces PO and an equal molar amount of α,α-dimethylbenzyl alcohol (DMBA), which is then converted to cumene in the hydrogenolysis unit, achieving a cumene cycle. The quality of the cumene product from the hydrogenolysis unit, mainly due to impurities such as α-methylstyrene and aromatic hydrocarbons containing the cumene structure, directly affects the operational stability of the oxidation and epoxidation units and the quality of the PO product.

[0003] Currently, copper and palladium catalysts are relatively well-studied and are recognized as having good activity and selectivity for DMBA hydrogenolysis, especially Pd catalysts, which are most widely used in industry. DMBA hydrogenolysis mainly follows an indirect reaction mechanism: first, dehydration under acid catalysis produces α-methylstyrene (AMS), and then AMS is hydrogenated at a metal center to produce cumene. Sumitomo Chemicals of Japan was the first to propose the CHP-to-PO technology route and achieve industrial application. CN109415331A proposed a reaction process using a layered packing of alumina and metal catalysts in a reactor for the catalytic hydrogenolysis of DMBA to produce cumene. CN112517059B prepared a dimethylbenzyl alcohol hydrogenolysis catalyst that combines the high low-temperature activity of noble metal catalysts with the excellent reaction selectivity of Cu-based catalysts. When used for the hydrogenolysis of dimethylbenzyl alcohol to produce cumene, it not only exhibits excellent activity and selectivity, but also achieves a conversion rate of over 99.5% and a selectivity of over 99.0% at a reaction temperature of 150℃. CN112679294B invented a Pd / Al2O3 bifunctional metal catalyst and a two-stage hydrogenation process, achieving a cumene yield of over 99.5%.

[0004] The DMBA hydrogenolysis unit has a complex feedstock composition, high reaction temperature, and generates a large amount of water, which could potentially affect the long-term stability of the catalyst. Noble metal Pd catalysts have a low hydrogen dissociation energy barrier, thus exhibiting good activity in the hydrogenolysis of dimethylbenzyl alcohol. Supports can be acidic components such as alumina, amorphous silica-alumina oxides, acidic clays, and zeolite molecular sieves, or activated carbon. Due to the strong hydrogenation activity of noble metals, side reactions such as over-hydrogenation are common, necessitating modification. The properties of the support are also crucial; excessively acidic support can lead to bimolecular etherification and polymerization, resulting in the deposition of heavy components on the catalyst surface, clogging catalyst pores or covering some active sites, thus reducing catalyst activity.

[0005] Pd is expensive, so improving the activity, selectivity, and lifespan of Pd-based catalysts is crucial for increasing the production efficiency of PO plants and reducing catalyst usage costs. Currently, research focuses more on improving catalyst activity, selectivity, and stability through catalyst or reaction process modifications, while research on catalyst deactivation during the reaction process and methods for catalyst regeneration after deactivation is limited. Summary of the Invention

[0006] As mentioned earlier, the hydrogenolysis of α,α-dimethylbenzyl alcohol to cumene in the presence of a hydrogenolysis catalyst is a common method in the chemical industry. Currently, more research focuses on improving the activity and selectivity of α,α-dimethylbenzyl alcohol hydrogenolysis by modifying the catalyst, with less attention paid to the technical issues of controlling the quality of cumene products and improving catalyst lifespan. The inventors of this invention discovered in their research that as the hydrogenolysis reaction proceeds, the content of α-methylstyrene in the product stream at the reaction outlet gradually increases. After extensive research, they proposed a method for the hydrogenolysis of α,α-dimethylbenzyl alcohol. This method mainly regenerates the hydrogenolysis catalyst based on the content of α-methylstyrene in the product stream at the reaction outlet. The regenerated hydrogenolysis catalyst can then be used for the next hydrogenolysis reaction, ensuring a high conversion rate of α,α-dimethylbenzyl alcohol, better regeneration effect, and extending the catalyst lifespan.

[0007] This invention provides a method for hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising: in the presence of a hydrogenolysis catalyst, reacting a hydrocarbon material containing α,α-dimethylbenzyl alcohol with hydrogen to obtain a product stream containing cumene; wherein the product stream contains α-methylstyrene, and when the α-methylstyrene content in the product stream is not higher than 1.0 wt%, regenerating the hydrogenolysis catalyst that has undergone the hydrogenolysis reaction to obtain a regenerated catalyst.

[0008] Through the above technical solution, the method of the present invention has a better regeneration effect and extends the service life of the catalyst by regenerating the hydrogenolysis catalyst at a specific time. Then, the hydrogenolysis reaction can be continued using the regenerated hydrogenolysis catalyst, which can ensure a high conversion rate of dimethylbenzyl alcohol. Attached Figure Description

[0009] Figure 1 This is a graph showing the change in the conversion rate of α,α-dimethylbenzyl alcohol over time when using catalyst Pre-1 in Example 1.

[0010] Figure 2 This is a comparison graph showing the change of α-methylstyrene content in the product stream containing isopropylbenzene over time when using catalyst Pre-1 from Example 1, regenerated catalyst Pre-11 from Example 1, and in the α,α-dimethylbenzyl alcohol hydrogenolysis process using Comparative Example 1. Detailed Implementation

[0011] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] This invention provides a method for hydrogenolysis of α,α-dimethylbenzyl alcohol, the method comprising: in the presence of a hydrogenolysis catalyst, reacting a hydrocarbon material containing α,α-dimethylbenzyl alcohol with hydrogen to obtain a product stream containing cumene; wherein the product stream contains α-methylstyrene, and when the α-methylstyrene content in the product stream is not higher than 1.0 wt%, regenerating the hydrogenolysis catalyst that has undergone the hydrogenolysis reaction to obtain a regenerated catalyst.

[0013] In this invention, it should be noted that during the hydrogenolysis of α,α-dimethylbenzyl alcohol, the hydrogenolysis catalyst can be a regenerated catalyst and / or a fresh catalyst. In this invention, a fresh catalyst refers to a catalyst that has been prepared but not yet used in the reaction, while a regenerated catalyst refers to a catalyst that has undergone regeneration treatment. The "catalyst for the hydrogenolysis reaction" can be either a fresh catalyst or a regenerated catalyst. The method of this invention proposes that regeneration be performed when the α-methylstyrene content in the cumene-containing product stream obtained from the hydrogenolysis reaction is not higher than 1.0 wt%, which has a better regeneration effect and extends the catalyst's lifespan. Furthermore, using the regenerated hydrogenolysis catalyst to continue the hydrogenolysis reaction ensures a high dimethylbenzyl alcohol conversion rate and cumene selectivity. Moreover, the hydrogenolysis catalyst of this invention, after undergoing the hydrogenolysis reaction, can be recycled multiple times, significantly improving the catalyst's lifespan. It can be recycled at least 5 times, while existing technologies can only be recycled 3 times.

[0014] According to a preferred embodiment of the present invention, when the α-methylstyrene content in the product stream is not higher than 0.8 wt% (e.g., 0.4 wt%, 0.62 wt%, 0.7 wt%, 0.8 wt%, or any two of the above values), the catalyst that has undergone hydrogenolysis is regenerated to obtain a regenerated catalyst. By employing the aforementioned embodiment, the catalyst deactivation rate is slowed, and its service life is increased, achieving better technical results and possessing broad industrial application value.

[0015] According to a particularly preferred embodiment of the present invention, when the α-methylstyrene content in the product stream is 0.4-0.8 wt%, the catalyst that has undergone hydrogenolysis is regenerated to obtain a regenerated catalyst. Using the aforementioned embodiment, when applied to hydrogenolysis, the conversion rate of α,α-dimethylbenzyl alcohol is high, and the α-methylstyrene content in the cumene product is low, resulting in a significant improvement in the quality of the cumene product. The catalyst deactivation rate is slow, and its service life is increased, achieving good technical results and possessing broad industrial application value.

[0016] According to a preferred embodiment of the present invention, the regeneration process is carried out in an inert atmosphere (e.g., nitrogen) with an oxygen content of 0.5-10 vol% (e.g., 0.5 vol%, 1 vol%, 2 vol%, 3 vol%, 5 vol%, 7 vol%, 8 vol%, or 10 vol%).

[0017] In this invention, an inert atmosphere with an oxygen content of 0.5-10% by volume refers to a main gas being an inert gas, which also contains 0.5-10% by volume oxygen.

[0018] According to a preferred embodiment of the present invention, the inert atmosphere further contains an organic acid. Using the aforementioned embodiment, the regenerated catalyst is used for hydrogenolysis, resulting in a high conversion rate of α,α-dimethylbenzyl alcohol, a low α-methylstyrene content in the cumene product, a significantly improved cumene product quality, a slow catalyst deactivation rate, and an increased service life. This achieves good technical results and has broad industrial application value.

[0019] In this invention, the inert atmosphere also contains organic acids. In one embodiment, the main gas is an inert gas, and it also contains 0.5-10% by volume of oxygen and organic acids.

[0020] According to a more preferred embodiment of the present invention, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid, lactic acid, and citric acid. Using the foregoing embodiments, the regenerated catalyst is used for hydrogenolysis, resulting in a high conversion rate of α,α-dimethylbenzyl alcohol and a low α-methylstyrene content in the cumene product.

[0021] According to a more preferred embodiment of the present invention, the organic acid is formic acid and / or acetic acid, preferably acetic acid. Using the aforementioned embodiments, the regenerated catalyst is used for hydrogenolysis, resulting in a high conversion rate of α,α-dimethylbenzyl alcohol and a low α-methylstyrene content in the cumene product.

[0022] According to a preferred embodiment of the present invention, the content of the organic acid in the inert atmosphere is 0.002 vol% to 0.01 vol%. Using the aforementioned embodiment, the regenerated catalyst is used for hydrogenolysis, resulting in a high conversion rate of α,α-dimethylbenzyl alcohol, a low α-methylstyrene content in the cumene product, and excellent selectivity for cumene.

[0023] According to a more preferred embodiment of the present invention, the volume content of the organic acid in the inert atmosphere is equal to the mass content of α-methylstyrene in the product stream / (80-100). Using the aforementioned embodiment, the regenerated catalyst is used for hydrogenolysis, resulting in a high conversion rate of α,α-dimethylbenzyl alcohol, a low α-methylstyrene content in the cumene product, and higher selectivity for cumene.

[0024] According to a preferred embodiment of the present invention, the conditions for the regeneration process include a regeneration temperature of 250-450°C.

[0025] According to a preferred embodiment of the present invention, the conditions for the regeneration treatment include: a gas hourly space velocity of 300-1000 h⁻¹. -1 .

[0026] According to the present invention, there is no particular limit to the endpoint of the regeneration treatment. Preferably, the regeneration treatment ends when the CO2 molar content in the reactor outlet gas is less than 0.3%, which is generally 12-48 hours.

[0027] According to the present invention, as long as it can promote the hydrogenolysis of α,α-dimethylbenzyl alcohol to prepare cumene, the specific type of hydrogenolysis catalyst is not particularly limited. According to a preferred embodiment of the present invention, the hydrogenolysis catalyst includes a support and an active component and an auxiliary agent supported on the support.

[0028] According to a preferred embodiment of the present invention, the active component includes metallic palladium and / or its oxide.

[0029] According to a preferred embodiment of the present invention, the additives include metal additives and / or their oxides.

[0030] According to a particularly preferred embodiment of the present invention, the metal additive is selected from at least one of Fe, Co, Ni, Ca, Mg and Cu.

[0031] According to a preferred embodiment of the present invention, the content of the active component in the hydrogenolysis catalyst, calculated by element, is 0.006-30 g / L.

[0032] According to a preferred embodiment of the present invention, the content of the auxiliary agent in the hydrogenolysis catalyst is 0.0001-2.0 g / L (based on elemental composition).

[0033] To further increase the diffusivity of reactants and products during use, according to a particularly preferred embodiment of the present invention, the hydrogenolysis catalyst also contains phosphorus and / or its oxides, based on the phosphorus content.

[0034] According to a particularly preferred embodiment of the present invention, the content of phosphorus and / or its oxides in the hydrogenolysis catalyst is 10-100 g / L, preferably 20-60 g / L.

[0035] In embodiments of the present invention where the catalyst contains phosphorus and / or its oxides, when preparing the corresponding hydrogenolysis catalyst, those skilled in the art can contact an aqueous solution of a phosphorus-containing compound with a support source, followed by drying and calcination to obtain a phosphorus-containing support, and then use the phosphorus-containing support with the corresponding active component source and auxiliary agent source to prepare the corresponding hydrogenolysis catalyst.

[0036] In this invention, there is no particular limitation on the concentration of the phosphorus-containing compound in the aqueous solution, as long as it can effectively react with the carrier.

[0037] According to a particularly preferred embodiment of the invention, the hydrogenolysis catalyst optionally contains silicon dioxide.

[0038] According to a particularly preferred embodiment of the present invention, the content of silicon dioxide in the hydrogenolysis catalyst is 0-600 g / L, preferably 0-400 g / L, based on silicon dioxide.

[0039] In this invention, "optionally" means that it may or may not contain.

[0040] In embodiments of the present invention where the catalyst contains silica, when specifically preparing the corresponding hydrogenolysis catalyst, those skilled in the art can contact a support source or a phosphorus-containing support with a silicon source, and then dry and calcine to obtain a silica-containing support or a phosphorus / silica-containing support. Then, the silica-containing support or the phosphorus / silica-containing support is used with the corresponding active component source and auxiliary agent source to prepare the corresponding hydrogenolysis catalyst.

[0041] According to a particularly preferred embodiment of the invention, the hydrogenolysis catalyst optionally contains a sulfur compound, preferably the sulfur compound is derived from sulfur-containing organic matter.

[0042] In embodiments of the present invention where the catalyst includes a sulfur-containing compound, when specifically preparing the corresponding hydrogenolysis catalyst, those skilled in the art can use the support and the active component on the support as the main body of the hydrogenolysis catalyst, and then load the sulfur-containing compound onto the main body of the hydrogenolysis catalyst.

[0043] According to a particularly preferred embodiment of the present invention, the content of sulfur-containing compounds in the hydrogenolysis catalyst is 0-5 g / L, preferably 0.01-1 g / L, based on the amount of sulfur element used.

[0044] The support in this invention can be any support in the field of hydrogenolysis catalysts, such as at least one of zirconium dioxide, alumina and activated carbon.

[0045] Specifically, the hydrogenolysis catalyst in this invention is prepared by the following method, which is merely an illustrative example of this invention:

[0046] S1 mixes one of the following: a support source, a phosphorus-containing support, or a phosphorus / silica-containing support, with a solution containing an active component source and an auxiliary source, and then dries and calcines to obtain a catalyst precursor.

[0047] S2 reduces the catalyst precursor, and optionally the reduced solid is mixed with a solution of sulfur-containing compounds and dried.

[0048] The preparation method of the phosphorus-containing carrier in this invention includes: mixing an aqueous solution of a phosphorus-containing compound with a carrier source, followed by drying and calcination.

[0049] The preparation method of the phosphorus / silica carrier in this invention includes: mixing the phosphorus-containing carrier with an aqueous solution of a silicon source, followed by drying and calcination.

[0050] In preparing the hydrogenolysis catalyst, the amounts of the support source, active component source, auxiliary source, phosphorus-containing compound, silicon source, and sulfur-containing compound can be selected according to the content of the support, active component, auxiliary, phosphorus and / or its oxides, silicon dioxide, and sulfur-containing compound in the final catalyst.

[0051] The carrier source described in this invention is selected from at least one of zirconium dioxide, alumina, and activated carbon.

[0052] The active component source in this invention is selected from palladium-containing compounds, such as palladium chloride, palladium nitrate, and chloropalladium acid.

[0053] The auxiliary agent source described in this invention is selected from at least one of the following: chloride of metal auxiliary agent, nitrate compound of metal auxiliary agent, and acetic acid compound of metal auxiliary agent.

[0054] The phosphorus-containing compound described in this invention is selected from at least one of phosphoric acid, potassium dihydrogen phosphate, phosphorous acid, calcium phosphate, and ammonium hydrogen phosphate.

[0055] The sulfur-containing organic compounds described in this invention are selected from at least one of tert-nonyl polysulfides, tert-butyl polysulfides, and thiophene.

[0056] The silicon source used in this invention is selected from silica gel aqueous solution.

[0057] In this invention, the solution used in the preparation of the catalyst refers to a solution formed by fully dissolving the solute in a suitable good solvent. Water is preferred as the solvent. There is no special limitation on the amount of solvent used, as long as it can fully dissolve the solute.

[0058] In the present invention, in step S1 of catalyst preparation, step S2 of catalyst preparation, preparation of phosphorus-containing support, and preparation of phosphorus / silica support, the drying described in each step can be carried out under vacuum or atmospheric pressure, preferably under atmospheric pressure, preferably at a drying temperature of 100-150°C, and preferably at a drying time of 6-12 hours.

[0059] In step S1 of the present invention, the preparation of the catalyst, the preparation of the phosphorus-containing support, and the preparation of the phosphorus / silica-containing support, the calcination temperature is preferably 400-750℃, more preferably 400-700℃; and the calcination time is preferably 2-6 hours.

[0060] In step S2 of catalyst preparation, the reduction treatment is carried out in a hydrogen atmosphere. Preferred reduction conditions include: a reduction temperature of 50-250°C, a reduction time of 12-24 h, and a hydrogen volume hourly space velocity of 300-800 h⁻¹.-1 .

[0061] In step S2 of the present invention, the solid material after reduction treatment is optionally mixed with a solution of sulfur-containing compound and dried in order to obtain a catalyst containing sulfur compound. When the catalyst does not contain sulfur compound, the catalyst is obtained by reduction treatment in step S2.

[0062] In this invention, the solvent in the solution of the sulfur-containing compound can be a conventional solvent in the art, such as cyclohexane.

[0063] According to the present invention, there is no particular limitation on the amount of hydrogen and hydrocarbon materials used in the hydrogenolysis reaction, as long as the hydrogenolysis reaction can proceed smoothly. Preferably, the molar ratio of hydrogen to α,α-dimethylbenzyl alcohol in the hydrocarbon material is (3-12):1.

[0064] According to a preferred embodiment of the present invention, the hydrogenolysis reaction is carried out using a liquid phase circulation method, preferably with a liquid phase circulation ratio of 1-10.

[0065] In this invention, the liquid phase circulation ratio is the ratio of the flow rate of the product stream containing isopropylbenzene circulating back to the inlet of the hydrogenolysis reactor to the flow rate of the hydrocarbon material containing α,α-dimethylbenzyl alcohol.

[0066] According to the present invention, the conditions for the hydrogenolysis reaction are not particularly limited as long as the objective of the present invention can be achieved. Preferably, the conditions for the hydrogenolysis reaction include: a reaction temperature of 150-250°C; a reaction pressure of 0.1-5 MPa; and a liquid hourly space velocity of 1-6 h⁻¹. -1 .

[0067] According to a preferred embodiment of the present invention, the hydrocarbon material contains 5-25 wt% α,α-dimethylbenzyl alcohol, 0-1.0 wt% α-methylstyrene, 0-2.0 wt% acetophenone, and 72-92 wt% cumene. The foregoing embodiment describes the main components of the hydrocarbon material, which may contain other components. The specific components are related to its upstream process, and will not be elaborated upon further in this invention.

[0068] The present invention will be described in detail below through examples. In the following examples, the raw materials were from a propylene oxide pilot plant. The composition of the raw materials and products was qualitatively and quantitatively analyzed using an Agilent Technologies gas chromatograph 7890. The calculation methods for the conversion rate of α,α-dimethylbenzyl alcohol and the selectivity of cumene are shown in (1) and (2).

[0069] α,α-Dimethylbenzyl alcohol conversion (%) = [(W 0 1-W t 1) / W 01]×100%; (1)

[0070] Cumene selectivity (%) = [(W t 2-W 0 2) / (W 0 1-W t 1)]×100%;(2)

[0071] w 0 1: The mass percentage of α,α-dimethylbenzyl alcohol in the raw material; w t 1: The mass percentage of α,α-dimethylbenzyl alcohol in the product;

[0072] w 0 2: The mass percentage of cumene in the raw materials; w t 2: The mass percentage of cumene in the product.

[0073] Example 1

[0074] Preparation of hydrogenolysis catalyst:

[0075] 1 L of alumina was mixed with 2000 g of an aqueous solution of chloropalladium acid-copper nitrate containing 3.0 g of palladium and 1.0 g of copper. The mixture was then dried at 110 °C for 8 hours and calcined at 500 °C for 4 hours. Finally, it was reduced in a hydrogen atmosphere for 4 hours to obtain palladium-based catalyst Pre-1. The reduction temperature was 35 °C and the hydrogen volume hourly space velocity was 300 h⁻¹. -1 .

[0076] Hydrogenolysis of α,α-dimethylbenzyl alcohol using fresh catalyst:

[0077] Hydrogenation was performed in a fixed-bed reactor loaded with catalyst Pre-1. The hydrogenation of a hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (main components: 25 wt% α,α-dimethylbenzyl alcohol, 0.1 wt% α-methylstyrene, 0.5 wt% acetophenone, 74 wt% cumene) was carried out continuously to obtain a product stream containing cumene. The hydrogenation conditions were: reaction temperature: 180℃; reaction pressure: 1.5 MPa; fresh oil volume hourly space velocity (FHSV): 2 h⁻¹. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0078] As the hydrogenation operation proceeded, the conversion rate of α,α-dimethylbenzyl alcohol over time using catalyst Pre-1 is shown in Table 1 and... Figure 1 As shown.

[0079] The changes in α-methylstyrene content over time in the product stream containing cumene are shown in Table 1 and... Figure 2 As shown.

[0080] The selectivity of cumene is shown in Table 2.

[0081] Catalyst regeneration and the use of the regenerated catalyst in the α,α-dimethylbenzyl alcohol hydrogenolysis process:

[0082] Hydrogenation is performed in a fixed-bed reactor loaded with catalyst Pre-1. Hydrogenation of hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (the same feedstock used in the α,α-dimethylbenzyl alcohol hydrogenolysis process with fresh catalyst) is carried out continuously to obtain a product stream containing cumene. When the α-methylstyrene content in the cumene product reaches 0.62 wt%, catalyst Pre-1 is regenerated for the first time to obtain regenerated catalyst Pre-11. The regenerated catalyst Pre-11 is then used to continue the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions. The benzyl alcohol hydrogenolysis process finally yields a product stream containing cumene. When the α-methylstyrene content in the cumene product is 0.62 wt%, the regenerated catalyst Pre-11 is regenerated a second time to obtain regenerated catalyst Pre-12. The regenerated catalyst Pre-12 is then used to carry out the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions, and the process is repeated in a co-cycle regeneration process (resulting in regenerated catalysts Pre-11, Pre-12, Pre-13, Pre-14, and Pre-15, respectively).

[0083] The conditions for hydrogenation operation were: reaction temperature: 180℃; reaction pressure: 1.5MPa; fresh oil volume hourly space velocity: 2h. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0084] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5% by volume was passed through the catalyst bed, the catalyst bed temperature was 450℃, and the gas hourly space velocity was 800 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 48h).

[0085] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing cumene when using regenerated catalysts Pre-11, Pre-12, and Pre-15 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0086] The selectivity of cumene is shown in Table 2.

[0087] The curve showing the change in α-methylstyrene content over time in the α,α-dimethylbenzyl alcohol hydrogenolysis process using the regenerated catalyst Pre-11 is shown below. Figure 2 As shown.

[0088] Example 2

[0089] Preparation of hydrogenolysis catalyst:

[0090] One liter of alumina was mixed with 600 grams of phosphoric acid aqueous solution containing 27 grams of phosphoric acid, dried at 110°C for 8 hours, and calcined at 400°C for 4 hours to obtain a phosphorus-containing catalyst support.

[0091] 1 L of the P-containing catalyst support was mixed with 600 g of a silica gel aqueous solution with a SiO2 mass concentration of 10%, dried at 110 °C for 8 hours and calcined at 500 °C for 4 hours to obtain a P / Si-containing support.

[0092] One liter of the P / Si-containing support was mixed with 2000 g of an aqueous solution of chloropalladium acid-copper nitrate containing 3.0 g of palladium and 1.0 g of copper. The mixture was dried at 110 °C for 8 hours, calcined at 500 °C for 4 hours, and then reduced in a hydrogen atmosphere for 4 hours to obtain catalyst Pre-2. The reduction temperature was 35 °C and the hydrogen volume hourly space velocity was 300 h⁻¹. -1 .

[0093] Hydrogenolysis of α,α-dimethylbenzyl alcohol using fresh catalyst:

[0094] Hydrogenation was performed in a fixed-bed reactor loaded with catalyst Pre-2. The hydrogenation of a hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (main components: 25 wt% α,α-dimethylbenzyl alcohol, 0.3 wt% α-methylstyrene, 0.5 wt% acetophenone, 74 wt% cumene) was carried out continuously to obtain a product stream containing cumene. The hydrogenation conditions were: reaction temperature: 180℃; reaction pressure: 1.5 MPa; fresh oil volume hourly space velocity (FHSV): 2 h⁻¹. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0095] As the hydrogenation operation proceeded, the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the cumene-containing product stream changed over time as shown in Table 1.

[0096] The selectivity of cumene is shown in Table 2.

[0097] Catalyst regeneration and the use of the regenerated catalyst in the α,α-dimethylbenzyl alcohol hydrogenolysis process:

[0098] Hydrogenation was performed in a fixed-bed reactor loaded with catalyst Pre-2. Hydrogenation of hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (the same feedstock used in the α,α-dimethylbenzyl alcohol hydrogenolysis process with fresh catalyst) was carried out continuously to obtain a product stream containing cumene. When the α-methylstyrene content in the cumene product reached 0.71 wt%, catalyst Pre-2 was regenerated for the first time to obtain regenerated catalyst Pre-21. The regenerated catalyst Pre-21 was then used to continue the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions. The benzyl alcohol hydrogenolysis process finally yields a product stream containing cumene. When the α-methylstyrene content in the cumene product is 0.71 wt%, the regenerated catalyst Pre-21 is regenerated a second time to obtain regenerated catalyst Pre-22. The regenerated catalyst Pre-22 is then used to carry out the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions, and the process is repeated in cycles (resulting in regenerated catalysts Pre-21, Pre-22, Pre-23, Pre-24, and Pre-25, respectively).

[0099] The conditions for hydrogenation operation were: 180℃; reaction pressure: 1.5MPa; fresh oil volume hourly space velocity: 2h. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0100] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5% by volume was passed through the catalyst bed, the catalyst bed temperature was 350℃, and the gas hourly space velocity was 600 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 36h).

[0101] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing isopropylbenzene when using regenerated catalysts Pre-21, Pre-22, and Pre-25 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0102] The selectivity of cumene is shown in Table 2.

[0103] Example 3

[0104] Preparation of hydrogenolysis catalyst:

[0105] One liter of alumina was mixed with 600 grams of phosphoric acid aqueous solution containing 27 grams of P, dried at 110°C for 8 hours, and calcined at 400°C for 4 hours to obtain a P-containing catalyst support.

[0106] 1 L of the P-containing catalyst support was mixed with 600 g of a silica gel aqueous solution with a SiO2 mass concentration of 10%, dried, and calcined at 500 °C to obtain a P / Si-containing support.

[0107] One liter of the P / Si-containing support was mixed with 2000 g of an aqueous solution of chloropalladium acid-copper nitrate containing 3.0 g of palladium and 1.0 g of copper. The mixture was dried at 110 °C for 8 hours and calcined at 500 °C for 4 hours to obtain an oxidized palladium-based catalyst precursor. This precursor was then reduced in a hydrogen atmosphere for 4 hours at 35 °C to obtain a reduced palladium-based catalyst precursor. The hydrogen volume hourly space velocity (HHSV) was 300 h⁻¹. -1 . ;

[0108] One liter of the above-mentioned reduced palladium-based catalyst precursor was impregnated with 550 g of cyclohexane solution containing 0.1 g of sulfur and then dried at 110 °C for 8 hours to obtain catalyst Pre-3.

[0109] Hydrogenolysis of α,α-dimethylbenzyl alcohol using fresh catalyst:

[0110] Hydrogenation was performed in a fixed-bed reactor loaded with catalyst Pre-3. The hydrogenation of a hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (main components: 25 wt% α,α-dimethylbenzyl alcohol, 0.3 wt% α-methylstyrene, 0.5 wt% acetophenone, 74 wt% cumene) was carried out continuously to obtain a product stream containing cumene. The hydrogenation conditions were: 180 °C; reaction pressure: 1.5 MPa; fresh oil volume hourly space velocity (VHSV): 2 h⁻¹. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0111] As the hydrogenation operation proceeded, the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the cumene-containing product stream changed over time as shown in Table 1.

[0112] The selectivity of cumene is shown in Table 2.

[0113] Catalyst regeneration and the use of the regenerated catalyst in the α,α-dimethylbenzyl alcohol hydrogenolysis process:

[0114] Hydrogenation was performed in a fixed-bed reactor loaded with catalyst Pre-3. Hydrogenation of hydrocarbon feedstock containing α,α-dimethylbenzyl alcohol (the same feedstock used in the α,α-dimethylbenzyl alcohol hydrogenolysis process with fresh catalyst) was carried out continuously to obtain a product stream containing cumene. When the α-methylstyrene content in the cumene product reached 0.62 wt%, catalyst Pre-3 was regenerated for the first time to obtain regenerated catalyst Pre-31. The regenerated catalyst Pre-31 was then used to continue the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions. The hydrogenolysis process yields a product stream containing cumene. When the α-methylstyrene content in the cumene product is 0.62 wt%, the regenerated catalyst Pre-31 is regenerated a second time to obtain regenerated catalyst Pre-32. The regenerated catalyst Pre-32 is then used to perform the α,α-dimethylbenzyl alcohol hydrogenolysis process under the same conditions, for a total of 5 cycles of regeneration (resulting in regenerated catalysts Pre-31, Pre-32, Pre-33, Pre-34, and Pre-35, respectively).

[0115] The conditions for hydrogenation operation were: 180℃; reaction pressure: 1.5MPa; fresh oil volume hourly space velocity: 2h. -1 Liquid phase circulation ratio: 2; Hydrogen / α,α-dimethylbenzyl alcohol molar ratio: 8.

[0116] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5% by volume was passed through the catalyst bed, the catalyst bed temperature was 250℃, and the gas hourly space velocity was 600 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 36h).

[0117] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing isopropylbenzene when using regenerated catalysts Pre-31, Pre-32, and Pre-35 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0118] The selectivity of cumene is shown in Table 2.

[0119] Example 4

[0120] The method is the same as in Example 1, except that:

[0121] In the process of catalyst regeneration and the use of regenerated catalyst in the hydrogenolysis of α,α-dimethylbenzyl alcohol:

[0122] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5 vol% and an acetic acid content of 0.006 vol% was passed through the catalyst bed, the catalyst bed temperature was 450℃, and the gas hourly space velocity was 800 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 24h).

[0123] The regenerated catalysts are sequentially designated as regenerated catalyst Pre-41, regenerated catalyst Pre-42, regenerated catalyst Pre-43, regenerated catalyst Pre-44, and regenerated catalyst Pre-45.

[0124] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing isopropylbenzene when using regenerated catalysts Pre-41, Pre-42, and Pre-45 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0125] The selectivity of cumene is shown in Table 2.

[0126] Example 5

[0127] The method is the same as in Example 2, except that:

[0128] In the process of catalyst regeneration and the use of regenerated catalyst in the hydrogenolysis of α,α-dimethylbenzyl alcohol:

[0129] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5 vol% and an acetic acid content of 0.007 vol% was passed through the catalyst bed, the catalyst bed temperature was 450℃, and the gas hourly space velocity was 800 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 24h).

[0130] The regenerated catalysts are sequentially designated as regenerated catalyst Pre-51, regenerated catalyst Pre-52, regenerated catalyst Pre-53, regenerated catalyst Pre-54, and regenerated catalyst Pre-55.

[0131] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing isopropylbenzene when using regenerated catalysts Pre-51, Pre-52, and Pre-55 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0132] The selectivity of cumene is shown in Table 2.

[0133] Example 6

[0134] The method is the same as in Example 4, except that:

[0135] In the process of catalyst regeneration and the use of regenerated catalyst in the hydrogenolysis of α,α-dimethylbenzyl alcohol:

[0136] The regeneration conditions were as follows: nitrogen gas with an oxygen content of 0.5 vol% and an acetic acid content of 0.002 vol% was passed through the catalyst bed, the catalyst bed temperature was 450℃, and the gas hourly space velocity was 800 h⁻¹. -1 Regeneration ends when the CO2 molar content in the reactor outlet gas is below 0.3% (time is 36h).

[0137] The regenerated catalysts are sequentially designated as regenerated catalyst Pre-61, regenerated catalyst Pre-62, regenerated catalyst Pre-63, regenerated catalyst Pre-64, and regenerated catalyst Pre-65.

[0138] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the product stream containing isopropylbenzene when using regenerated catalysts Pre-61, Pre-62, and Pre-65 for the hydrogenolysis process of α,α-dimethylbenzyl alcohol.

[0139] The selectivity of cumene is shown in Table 2.

[0140] Comparative Example 1

[0141] The method is the same as in Example 1, except that:

[0142] In the process of catalyst regeneration and the use of regenerated catalyst in the hydrogenolysis of α,α-dimethylbenzyl alcohol:

[0143] In each of the five regeneration cycles, the catalyst was regenerated when the α-methylstyrene content in the cumene product was 1.08 wt%. The regenerated catalysts were sequentially named Pre-D1, Pre-D2, Pre-D3, Pre-D4, and Pre-D5.

[0144] Table 1 shows the conversion rate of α,α-dimethylbenzyl alcohol and the α-methylstyrene content in the cumene-containing product stream when using regenerated catalysts Pre-D1, Pre-D2, and Pre-D5 for the α,α-dimethylbenzyl alcohol hydrogenolysis process. When using regenerated catalyst Pre-D1, the change in α-methylstyrene content in the cumene-containing product stream over time is shown in Table 1. Figure 2 As shown.

[0145] The selectivity of cumene is shown in Table 2.

[0146] Table 1

[0147]

[0148]

[0149]

[0150] Table 2

[0151]

[0152]

[0153] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for hydrogenolysis of α,α-dimethylbenzyl alcohol, characterized in that: The method includes: In the presence of a hydrogenolysis catalyst, a hydrocarbon material containing α,α-dimethylbenzyl alcohol is subjected to a hydrogenolysis reaction with hydrogen to obtain a product stream containing cumene; The product stream contains α-methylstyrene, and when the content of α-methylstyrene in the product stream is not higher than 1.0 wt %, the hydrogenolysis catalyst that has undergone hydrogenolysis reaction is regenerated to obtain a regenerated catalyst.

2. The method according to claim 1, wherein: When the content of α-methylstyrene in the product stream is not higher than 0.8 wt %, preferably 0.4-0.8 wt %, the catalyst subjected to the hydrogenolysis reaction is regenerated to obtain a regenerated catalyst.

3. The method according to claim 1 or 2, wherein: The regeneration treatment is carried out in an inert atmosphere containing 0.5-10% by volume of oxygen; Preferably, the inert atmosphere further contains an organic acid; More preferably, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid, lactic acid and citric acid, preferably formic acid and / or acetic acid; and / or The content of the organic acid in the inert atmosphere is 0.002 volume %-0.01 volume %, preferably the volume content of the organic acid in the inert atmosphere = the mass content of α-methylstyrene in the product flow / (80-100).

4. The method according to claim 3, wherein: The conditions of the regeneration process include: Regeneration temperature is 250-450°C; and / or Gas volume space velocity is 300-1000h -1 ; and / or The regeneration time is 12-48h.

5. The method according to any one of claims 1 to 4, wherein: The hydrogenolysis catalyst comprises a carrier and an active component and an auxiliary agent supported on the carrier; Preferably, the active component comprises metallic palladium and / or its oxide; and / or The additive comprises a metal additive and / or an oxide thereof, preferably the metal additive is selected from at least one of Fe, Co, Ni, Ca, Mg and Cu; and / or The hydrogenolysis catalyst contains 0.006-30 g / L of active components, calculated as elements; and / or In the hydrogenolysis catalyst, the content of the auxiliary agent is 0.0001-2.0 g / L, calculated as the element.

6. The method according to claim 5, wherein: The hydrogenolysis catalyst further contains phosphorus and / or its oxides, and the content of phosphorus and / or its oxides in the hydrogenolysis catalyst is preferably 10-100 g / L, preferably 20-60 g / L, based on the content of phosphorus element; and / or The hydrogenolysis catalyst optionally contains silicon dioxide. Calculated as silicon dioxide, the content of silicon dioxide in the hydrogenolysis catalyst is preferably 0-600 g / L, preferably 0-400 g / L.

7. The method according to claim 5 or 6, wherein: The hydrogenolysis catalyst also includes a sulfur-containing compound, and the source of the sulfur compound is preferably a sulfur-containing organic matter; Preferably, the content of sulfur-containing compounds in the hydrogenolysis catalyst is 0-5 g / L, preferably 0.01-1 g / L, based on the amount of sulfur element used; and / or The sulfur-containing organic matter is selected from at least one of tert-nonyl polysulfide, tert-butyl polysulfide and thiophene.

8. The method according to any one of claims 1 to 6, wherein: The molar ratio of hydrogen to α,α-dimethylbenzyl alcohol in the hydrocarbon material is (3-12):1; Preferably, a liquid phase circulation method is adopted when carrying out the hydrogenolysis reaction, and preferably the liquid phase circulation ratio is 1-10.

9. The method according to any one of claims 1 to 8, wherein: The conditions of the hydrogenolysis reaction include: The reaction temperature is 150-250°C; and / or Reaction pressure 0.1-5MPa; and / or Liquid phase volume space velocity 1-6h -1 .

10. The method according to any one of claims 1 to 9, wherein: The hydrocarbon material contains 5-25wt% of α,α-dimethylbenzyl alcohol, 0-1.0wt% of α-methylstyrene, 0-2.0wt% of acetophenone and 72-92wt% of isopropylbenzene.

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