A process for the synthesis of cyclohexene co-producing primary alcohols

Abstract

The present application belongs to the technical field of catalytic synthesis of fine chemicals, and particularly relates to a method for co-producing cyclohexene and primary alcohol. Cyclohexane and low-carbon alkylene oxide are introduced into a fixed bed reactor, and a chemical reaction occurs on a tungsten and molybdenum oxide catalyst treated by gamma rays to obtain cyclohexene and primary alcohol. The method has excellent selectivity for cyclohexene and primary alcohol, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalytic synthesis of fine chemicals, and particularly relates to a process and a catalyst for co-producing cyclohexene and primary alcohol. BACKGROUND

[0002] Cyclohexene is an important chemical raw material, which can be directly used to synthesize hexanediol, adipic acid, and polycarbonate by ring-opening polymerization with carbon dioxide. It can be widely used in organic synthesis and has a wide application prospect in chemical industry, pharmaceutical industry and petroleum industry. Primary alcohol is also an important organic compound, which has a wide application in chemical industry, medical industry, food industry, and industrial and agricultural production. For example, such compounds are used as organic solvents with excellent performance, important intermediate raw materials in chemical synthesis, and the like.

[0003] The generation of cyclohexene mainly includes benzene partial hydrogenation method and cyclohexane selective dehydrogenation method. Taking the cyclohexane selective dehydrogenation technology as an example, Chinese patent CN112844352B discloses an application of a carbon material catalyst in cyclohexane oxidative dehydrogenation. The nano diamond treated by high-temperature calcination has high selectivity in catalyzing cyclohexene product in the cyclohexane oxidative dehydrogenation reaction and effectively inhibits the combustion reaction. The selectivity of the cyclohexene product is 60%. Primary alcohol is usually prepared by aldehyde hydrogenation process. For example, Chinese patent CN113105299B discloses a method for synthesizing primary alcohol in an aqueous phase. Aldehyde is used as a raw material, and water is selected as a solvent. The aldehyde is obtained by catalytic hydrogenation reaction in the presence of a water-soluble catalyst, and the catalyst used is a metal iridium complex. SUMMARY

[0004] The purpose of the present application is to provide a method for synthesizing cyclohexene and co-producing primary alcohol.

[0005] The main feature of the present application is that a catalyst containing rich oxygen vacancies and high metal dispersion is prepared by using high-energy gamma rays. Under the action of the catalyst, cyclohexane and low-carbon alkylene oxide occur chemical reaction, and cyclohexene and primary alcohol are obtained with high selectivity.

[0006] The preparation method of the copper-based catalyst according to the present application is realized by the following technical scheme:

[0007] Cyclohexane and low-carbon alkylene oxide are introduced into a fixed bed reactor to occur chemical reaction on the catalyst to obtain cyclohexene and primary alcohol. The catalyst includes one of tungsten and molybdenum oxides.

[0008] Generally, the molar ratio of the low-carbon alkylene oxide to the cyclohexane is 1-3.

[0009] The reaction temperature is 300-600 DEG C, the pressure is normal pressure-2 MPa, the space velocity of cyclohexane gas is 1x10 4 ~1x105 h -1。

[0010] The catalyst is prepared by a sol-gel method, a mixed solution of metal precursor salt and citric acid is prepared, then the mixed solution is evaporated, calcined, granulated and molded to obtain a catalyst precursor, and the catalyst precursor is placed in a particle bombardment box and treated under gamma rays to obtain the catalyst.

[0011] The molar ratio of citric acid to metal precursor salt is 2-5, and the evaporation temperature is 70-90 DEG C.

[0012] The calcination atmosphere is one of nitrogen and argon, the calcination temperature is 300-500 DEG C, and the calcination time is 1-3 h.

[0013] The frequency of the gamma rays is 1x10 13 ~1x10 28 Hz.

[0014] The treatment time under gamma rays is 5-20 min.

[0015] The low-carbon alkylene oxide is one of ethylene oxide and propylene oxide.

[0016] The selectivity of cyclohexene in the method is more than 90%.

[0017] Compared with the prior art, the selectivity of cyclohexene is high, and the primary alcohol with high added value can be simultaneously produced. Embodiment

[0018] The following examples are only used to further explain the content and effects of the present application, and are not a limitation on the present application.

[0019] Example 1

[0020] 1 mol of ammonium metatungstate and 5 mol of citric acid are dissolved in 1000 mL of deionized water to prepare a mixed solution, then the mixed solution is evaporated at 70 DEG C, calcined at 500 DEG C under nitrogen atmosphere for 1 h, and after cooling, the catalyst precursor is obtained by granulation and molding, and the catalyst precursor is placed in a particle bombardment box and treated under 1x10 28 Hz gamma rays for 5 min to obtain the catalyst cat1.

[0021] Example 2

[0022] 1 mol of ammonium molybdate and 4 mol of citric acid are dissolved in 800 mL of deionized water to prepare a mixed solution, then the mixed solution is evaporated at 80 DEG C, calcined at 400 DEG C under nitrogen atmosphere for 1.5 h, and after cooling, the catalyst precursor is obtained by granulation and molding, and the catalyst precursor is placed in a particle bombardment box and treated under 1x10 20After being treated under 1 x 10

[0023] Example 3

[0024] 1 mol of ammonium metatungstate and 3 mol of citric acid were dissolved in 800 mL of deionized water to form a mixed solution, which was then evaporated at 90°C and calcined at 450°C for 2 h under an argon atmosphere; after cooling, the catalyst precursor was taken out, granulated, and molded to obtain a catalyst, which was placed in a particle bombardment box and treated under 1 x 10 18 After being treated under 1 x 10

[0025] Example 4

[0026] 1 mol of ammonium metatungstate and 2 mol of citric acid were dissolved in 1000 mL of deionized water to form a mixed solution, which was then evaporated at 90°C and calcined at 300°C for 3 h under an argon atmosphere; after cooling, the catalyst precursor was taken out, granulated, and molded to obtain a catalyst, which was placed in a particle bombardment box and treated under 1 x 10 15 After being treated under 1 x 10

[0027] Example 5

[0028] 1 mol of ammonium molybdate and 3 mol of citric acid were dissolved in 800 mL of deionized water to form a mixed solution, which was then evaporated at 80°C and calcined at 400°C for 2 h under an argon atmosphere; after cooling, the catalyst precursor was taken out, granulated, and molded to obtain a catalyst, which was placed in a particle bombardment box and treated under 1 x 10 13 After being treated under 1 x 10

[0029] Example 6

[0030] 1 mol of ammonium metatungstate and 3.5 mol of citric acid were dissolved in 1000 mL of deionized water to form a mixed solution, which was then evaporated at 90°C and calcined at 450°C for 3 h under an argon atmosphere; after cooling, the catalyst precursor was taken out, granulated, and molded to obtain a catalyst, which was placed in a particle bombardment box and treated under 1 x 10 22 After being treated under 1 x 10

[0031] Example 7

[0032] 1 mol of ammonium molybdate and 5 mol of citric acid were dissolved in 1000 mL of deionized water to form a mixed solution, which was then evaporated at 70°C and calcined at 400°C for 1 h under a nitrogen atmosphere; after cooling, the catalyst precursor was taken out, granulated, and molded to obtain a catalyst, which was placed in a particle bombardment box and treated under 1 x 10 20After being treated under gamma ray of 0.1 Mrad for 15 min, catalyst cat7 was obtained.

[0033] Example 8

[0034] 1 mol of ammonium molybdate and 5 mol of citric acid were dissolved in 1000 mL of deionized water to form a mixed solution, which was then evaporated at 70°C and calcined at 400°C for 1 h under nitrogen atmosphere. After cooling, the catalyst was obtained by granulation and molding. Example 9

[0035] The oxygen vacancy ratio (expressed by weight gain rate %) of the catalyst was determined by O2-TG, and the metal dispersion was determined by the combined method of XPS and ICP.

[0036] The above-prepared cat1~cat8 catalysts were used in the reaction of cyclohexane and low-carbon alkylene oxide, and the results are shown in the following table.

[0037] Table 1 Test results of catalyst performance

[0038]

[0039] As can be seen from Table 1, the catalyst prepared by the method of the present application has a high oxygen vacancy ratio and metal dispersion, and has good catalytic performance in the reaction of cyclohexane and alkylene oxide to prepare cyclohexene and primary alcohol.

Claims

1. A method for synthesizing cyclohexene and co-producing primary alcohol, characterized in that... Cyclohexane and low-carbon epoxide alkane are fed into a fixed-bed reactor and react chemically on a catalyst to yield cyclohexene and a primary alcohol. The catalyst includes one of tungsten or molybdenum oxides and is prepared using a sol-gel method. A mixed solution of a tungsten or molybdenum precursor salt and citric acid is prepared, then evaporated, calcined, granulated, and shaped to obtain the catalyst precursor. The catalyst precursor is placed in a particle bombardment chamber at a frequency of 1×10⁻⁶. 13 ~1×10 28 The catalyst was obtained after treatment with Hz gamma rays for 5-20 min.

2. The method according to claim 1, characterized in that, The molar ratio of the low-carbon epoxide alkane to cyclohexane is 1 to 3.

3. The method according to claim 1, characterized in that, The reaction temperature is 300~600℃, the pressure is atmospheric pressure to 2MPa, and the hourly space velocity of cyclohexane is 1×10⁻⁶. 4 ~1×10 5 h -1 .

4. The method according to claim 1, characterized in that, The molar ratio of citric acid to metal precursor salt is 2 to 5.

5. The method according to claim 1, characterized in that, The evaporation temperature is 70~90℃.

6. The method according to claim 1, characterized in that, The roasting atmosphere is either nitrogen or argon; the roasting temperature is 300~500℃, and the roasting time is 1~3h.

7. The method according to claim 1, characterized in that, The low-carbon epoxy alkane is one of ethylene oxide and propylene oxide.

8. The method according to claim 1, characterized in that, The selectivity of cyclohexene is over 90%.

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