阅读说明：本技术 苯酚加氢制备环己酮的方法 (Method for preparing cyclohexanone by phenol hydrogenation ) 是由 尤陈佳 王高伟 高焕新 于 2018-06-06 设计创作，主要内容包括：本发明涉及一种苯酚加氢制备环己酮的方法。所述方法包括在临氢反应条件下,使原料苯酚与催化剂接触制备环己酮的步骤；所述催化剂包含95～99.9重量％载体和0.1～5重量％Pd,相对于载体和Pd的总重量；所述载体包含至少两种晶型的氧化铝,其中γ-Al<Sub>2</Sub>O<Sub>3</Sub>的含量为60～99重量％,相对于载体和Pd的总重量。所述方法可用于苯酚加氢制备环己酮的工业生产中。(the invention relates to a method for preparing cyclohexanone by phenol hydrogenation. The method comprises the steps of contacting raw material phenol with a catalyst under the condition of hydrogen reaction to prepare cyclohexanone; the catalyst comprises 95-99.9 wt% of a carrier and 0.1-5 wt% of Pd, relative to the total weight of the carrier and Pd; the carrier comprises at least two crystal forms of alumina, wherein gamma-Al 2 O 3 The content of (b) is 60 to 99 wt% with respect to the total weight of the carrier and Pd. The method can be used for industrial production of cyclohexanone by phenol hydrogenation.)

1. A method for preparing cyclohexanone by phenol hydrogenation comprises the step of contacting raw material phenol with a catalyst under the condition of hydrogen reaction to prepare cyclohexanone;

The catalyst comprises 95-99.9 wt% of a carrier and 0.1-5 wt% of Pd, relative to the total weight of the carrier and Pd;

the carrier comprises at least two crystal forms of alumina, wherein gamma-Al₂O₃The content of (b) is 60 to 99 wt% with respect to the total weight of the carrier and Pd.

2. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein γ -Al is contained in the carrier₂O₃The content of (b) is 80 to 95 wt% with respect to the weight of the carrier.

3. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein γ -Al is removed by the carrier₂O₃in addition, it also contains alpha-Al₂O₃、β-Al₂O₃、θ-Al₂O₃、η-Al₂O₃、κ-Al₂O₃And delta-Al₂O₃At least one of the group consisting of.

4. The method for preparing cyclohexanone by hydrogenating phenol according to claim 3, wherein γ -Al is removed by the carrier₂O₃In addition, it also contains alpha-Al₂O₃、θ-Al₂O₃And delta-Al₂O₃At least one of the group consisting of.

5. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein the Pd content is 0.3-3 wt%.

6. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein the reaction conditions in the hydrogenation reaction comprise: the reaction temperature is 140-220 ℃, the reaction pressure is 0.1-3.0 MPa, and the weight space velocity of phenol is 0.1-3 hours^-1And the molar ratio of the hydrogen to the phenol is 2-10: 1.

7. The method for preparing cyclohexanone by hydrogenating phenol according to claim 6, wherein the reaction conditions in the hydrogenation reaction comprise: the reaction temperature is 150-190 ℃, the reaction pressure is 0.1-1.5 MPa, and the weight space velocity of phenol is 0.4-2 hours^-1And the molar ratio of the hydrogen to the phenol is 3-8: 1.

8. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein the raw material phenol comprises 20-90 wt% of cyclohexanone relative to the weight of the raw material phenol.

9. The method for preparing cyclohexanone by hydrogenating phenol according to claim 8, wherein the raw material phenol comprises 30-80 wt% of cyclohexanone relative to the weight of the raw material phenol.

10. The method for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein the raw material phenol is contacted with the catalyst in a fixed bed reactor.

Technical Field

The invention relates to a method for preparing cyclohexanone by phenol hydrogenation.

Background

Cyclohexanone is an important organic chemical raw material for synthesizing fiber nylon 6 and nylon 66 monomers, caprolactam and adipic acid, and has wide application in the fields of medicines, coatings, dyes and the like.

The cyclohexane oxidation method is the most common chemical process at home and abroad, but the process has the problems of low cyclohexane conversion rate, low cyclohexanone selectivity, serious three wastes in the process, low catalyst utilization rate, difficult separation and the like. The phenol hydrogenation method has the advantages of short production flow, high cyclohexanone yield, stable technology and the like, and the process is safer than the cyclohexane oxidation method, so that the method has competitive advantage in recent years. The process for preparing cyclohexanone by phenol gas-phase hydrogenation is an efficient and environment-friendly synthetic route, adopts a fixed bed device, is simple to operate and control, is easy to recover the catalyst, and can realize continuous production.

Document GB1063357A uses Pd/gamma-Al doped with alkaline earth oxides₂O₃The catalyst has the advantages that at the temperature of 100-200 ℃, the conversion rate of phenol is more than 95%, the yield of cyclohexanone is more than 92%, unconverted phenol still exists in a system, and the phenol, the cyclohexanone and cyclohexanol can form an azeotrope, so that the difficulty is increased for the separation of subsequent products. Wanghong Jing et Al reported Ba-modified Pd/Al₂O₃The influence of the catalyst on the phenol hydrogenation reaction performance, the addition of Ba increased the phenol conversion to 100% and the cyclohexanone yield to 80% (catalytic science 2009, 30, 933). Document NL7704346A describes Pd/Al₂O₃Adding Na as catalyst₂CO₃Or NaOH, cyclohexanone selectivity is 95%, phenol conversion is only 89%. Y.z.chen et al reported that Pd/magnesium aluminum hydrotalcite catalyzed a gas phase hydrogenation of phenol to cyclohexanone with a phenol conversion of only 40% and a cyclohexanone selectivity of 95% (appl.catal.a,1999,177, 1).

The reaction process for preparing cyclohexanone by phenol hydrogenation needs high reaction activity and high selectivity, so that high-purity cyclohexanone is obtained. However, the catalysts reported in the above patents and literature for the industrial production of cyclohexanone still have the disadvantages of low conversion and selectivity. Therefore, it is necessary to develop a catalyst for preparing cyclohexanone by phenol hydrogenation with high efficiency and high selectivity.

Disclosure of Invention

The present inventors have assiduously studied a system based on the prior art and found that at least one of the aforementioned problems can be solved by using a Pd catalyst comprising at least two kinds of alumina as a carrier, and thus have completed the present invention.

Specifically, the invention relates to a method for preparing cyclohexanone by phenol hydrogenation. The method comprises the steps of contacting raw material phenol with a catalyst under the condition of hydrogen reaction to prepare cyclohexanone; the catalyst comprises 95-99.9 wt% of a carrier and 0.1-5 wt% of Pd, relative to the total weight of the carrier and Pd; the carrier comprises at least two crystal forms of alumina, whereinγ-Al₂O₃The content of (b) is 60 to 99 wt% with respect to the total weight of the carrier and Pd.

According to one aspect of the invention, in the support, γ -Al₂O₃The content of (b) is 80 to 95 wt% with respect to the weight of the carrier.

According to one aspect of the invention, the support is gamma-Al-depleted₂O₃In addition, it also contains alpha-Al₂O₃、β-Al₂O₃、θ-Al₂O₃、η-Al₂O₃、κ-Al₂O₃And delta-Al₂O₃At least one selected from the group consisting of alpha-Al, preferably further containing₂O₃、θ-Al₂O₃And delta-Al₂O₃At least one of the group consisting of.

According to one aspect of the invention, the Pd is present in an amount of 0.3 to 3 wt.%.

According to one aspect of the invention, the hydro-reaction conditions include: the reaction temperature is 140-220 ℃, the reaction pressure is 0.1-3.0 MPa, and the weight space velocity of phenol is 0.1-3 hours^-1The molar ratio of hydrogen to phenol is 2-10: 1; the preferable reaction temperature is 150-190 ℃, the reaction pressure is 0.1-1.5 MPa, and the weight space velocity of phenol is 0.4-2 hours^-1And the molar ratio of the hydrogen to the phenol is 3-8: 1.

According to one aspect of the present invention, the feed phenol comprises 20 to 90 wt% cyclohexanone, preferably 30 to 80 wt% cyclohexanone, relative to the weight of the feed phenol.

According to one aspect of the invention, the starting phenol is contacted with the catalyst in a fixed bed reactor.

According to one aspect of the invention, the Pd/alumina catalyst is prepared by a well-known impregnation method, and is dried and reduced to obtain the supported Pd/alumina catalyst.

The invention has the technical effects that:

According to the method of the invention, at least gamma-Al is used₂O₃The two crystal forms of alumina are used as catalyst carriers, and the conversion rate of phenol can reach 99.5 percentAbove, the selectivity of cyclohexanone can reach more than 97%.

According to the method, the raw material phenol comprises 20-90 wt% of cyclohexanone, namely the cyclohexanone is used as a solvent, instead of water, dichloromethane, ethanol, tetrahydrofuran or 1, 4-dioxane which is used as a solvent in the prior art, no impurity is introduced, and the subsequent separation of the product is convenient, so that the economy is improved.

Detailed Description

The following detailed description of the embodiments of the present invention is provided, but it should be noted that the scope of the present invention is not limited by the embodiments, but is defined by the appended claims.

All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference in their entirety. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, including definitions, will control.

It should be expressly understood that two or more of the aspects (or embodiments) disclosed in the context of this specification can be combined with each other as desired, and that such combined aspects (e.g., methods or systems) are incorporated in and constitute a part of this original disclosure, while remaining within the scope of the present invention.

Unless otherwise expressly indicated, all percentages, parts, ratios, etc. mentioned in this specification are by weight unless otherwise not in accordance with the conventional knowledge of those skilled in the art.

[ example 1 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.1%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 1).

[ example 2 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂Impregnation in aqueous solution (w (pd) ═ g0.3%), dried and reduced to obtain the Pd/alumina catalyst (catalyst A2).

[ example 3 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.5%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 3).

[ example 4 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 1%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 4).

[ example 5 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 3%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 5).

[ example 6 ]

27 g of gamma-Al₂O₃And 3g of alpha-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 5%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 6).

[ example 7 ]

28.5 g of gamma-Al₂O₃And 1.5 g of delta-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.5%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 7).

[ example 8 ]

29.7g of gamma-Al₂O₃And 0.3g of theta-Al₂O₃Mixing the powder with PdCl₂The aqueous solution was immersed overnight (w (Pd) ═ 0.5%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst A8).

[ example 9 ]

26 g of gamma-Al₂O₃2 g of alpha-Al₂O₃And 2 g of theta-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.3%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 9).

[ example 10 ]

20 g of gamma-Al₂O₃6 g of alpha-Al₂O₃And 4 g of delta-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.3%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 10).

[ example 11 ]

27 g of gamma-Al₂O₃2 g of delta-Al₂O₃And 1 g of theta-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.3%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 11).

[ example 12 ]

18 g of gamma-Al₂O₃4 g of alpha-Al₂O₃4 g of delta-Al₂O₃And 4 g of theta-Al₂O₃Mixing the powder with PdCl₂The catalyst was impregnated with an aqueous solution (w (Pd) ═ 0.3%), dried, and reduced to obtain a Pd/alumina catalyst (catalyst a 12).

[ COMPARATIVE EXAMPLES 1 to 3 ]

30 g of gamma-Al₂O₃、α-Al₂O₃、θ-Al₂O₃The powder is respectively mixed with PdCl₂The catalyst B1 to B3 were obtained by immersing the catalyst in an aqueous solution overnight (w (pd) ═ 0.3%), followed by drying and reduction.

The synthesized catalyst is used for preparing cyclohexanone by phenol hydrogenation, and the reaction conditions are as follows:

5 g of the catalysts A1-A12 and B1-B3 were respectively loaded into a reactor for evaluation, and a raw material (raw material phenol including 70 wt% cyclohexanone) was preheated and then mixed with hydrogen, and the mixture was introduced into the reactor to contact the catalyst for reaction. Controlling the reaction temperature at 160 deg.C, the reaction pressure at 0.1MPa, and the mass space velocity of phenol at 0.6hr^-1The molar ratio of hydrogen to phenol was 5:1 and the product was collected and analyzed by gas chromatography. The results are shown in Table 1.

TABLE 1