CN107398299B - A kind of preparation method and application of modified TS-1 catalyst - Google Patents

Abstract

A preparation method and application of a modified TS-1 catalyst, taking 0.2g of TS-1 catalyst into a ceramic crucible and placing it in a heating cavity of an ultraviolet high temperature reactor; vacuuming the cavity pressure to 2Pa, and then evacuating the cavity pressure to 2Pa for 2min Internally heated to 425°C; the sample was irradiated with ultraviolet light for 10 min to obtain the modified TS-1 catalyst. The application of the modified TS-1 catalyst in the reaction of cyclohexanone ammoximation to prepare cyclohexanone oxime. The modified TS-1 catalyst showed higher catalytic activity and higher selectivity to the target product cyclohexanone oxime in the cyclohexanone ammoximation reaction.

Description

A kind of preparation method and application of modified TS-1 catalyst

technical field

The invention relates to the field of zeolite molecular sieve and industrial catalysis, in particular to a preparation method and application of a modified TS-1 catalyst.

Background technique

The synthesis of titanium-silicon molecular sieve TS-1 and its successful application as a catalyst for the selective oxidation of organic compounds are considered to be an important milestone in the field of zeolite molecular sieve catalysis in the 1980s. TS-1 is a zeolite molecular sieve with MFI structure, which consists of straight channels (with a pore size of about 0.57nm × 0.51nm), zig-zag channels (with a pore size of about 0.54nm) and a phase with them. It is composed of connected intersecting channels (intersections with a diameter of about 0.90 nm), which is characterized by replacing part of Si ^{4+ in the framework of the all-silicon molecular sieve with Ti 4+ .} Due to the six-coordination characteristics of Ti ⁴⁺ ions, its titanium oxide tetrahedron has high energy, and its structure has electronic defects, which has the potential to accept electron pairs, and has unique adsorption and activation properties for H ₂ O ₂ or organic peroxy compounds. At present, the main reactions that have used TS-1 as a catalyst for selective oxidation of organic compounds include olefin epoxidation, aromatic hydrocarbon hydroxylation, ketone ammoxidation, alkane oxidation and alcohol oxidation. Among them, the production process of one-step synthesis of cyclohexanone oxime using TS-1 as a catalyst and cyclohexanone, ammonia and hydrogen peroxide as reaction raw materials has successfully achieved industrial-scale production.

Cyclohexanone oxime is a key intermediate in the production of nylon-6 monomer ε-caprolactam. The traditional production process is as follows: cyclohexanone and hydroxylamine undergo non-catalytic oxidation reaction to generate cyclohexanone oxime, and cyclohexanone oxime is dissolved in oleum. ε-caprolactam was prepared by liquid phase Beckmann rearrangement reaction under catalysis. Due to the use of toxic hydroxylamine and strong corrosive oleum in the production process, and the production of a large amount of by-products of ammonium sulfate (about 2.8 tons of ammonium sulfate per ton of ε-caprolactam) and nitrogen oxides, it has caused serious problems. environmental pollution problem.

In the 1980s, the Italian company Montedipe SpA (now EniChem SpA) successfully developed the cyclohexanone ammoximation process. The process used cyclohexanone, ammonia and H ₂ O ₂ as raw materials, and the catalytic effect of titanium silicon molecular sieve TS-1 was Cyclohexanone oxime can be directly prepared by ammoximation reaction. Later, Japan's Sumitomo Chemical Company developed a production process for preparing ε-caprolactam by gas-phase Beckmann rearrangement reaction of cyclohexanone oxime. This reaction process replaced concentrated sulfuric acid with a high-silicon MFI molecular sieve catalyst to avoid the production of ammonium sulfate by-products. Compared with the traditional process, the production process of preparing ε-caprolactam by combining cyclohexanone ammoximation and gas-phase Beckmann rearrangement reaction has the following advantages: less intermediate steps, no need to synthesize hydroxylamine, shortening the process flow; low reaction temperature, reducing The energy consumption is reduced; the catalyst can be reused; there is no by-product ammonium sulfate, and the only by-product produced is water (as shown in the following formula), which improves the economic and social benefits of ε-caprolactam production, and realizes "zero discharge". In line with the requirements of green chemical development.

Ammoximation of cyclohexanone and gas-phase Beckmann rearrangement of cyclohexanone oxime to produce ε-caprolactam

However, studies have shown that in the production process of cyclohexanone ammoximation to cyclohexanone oxime under the catalysis of TS-1, the catalytic activity of TS-1 is limited by intracrystalline mass transfer, and with the crystal size of TS-1 The catalytic activity decreased gradually with the increase of , and when the crystal size was larger than 0.5um, the catalytic activity decreased significantly.

In order to improve the mass transfer performance of TS-1 catalyst, scientists synthesized nano-scale TS-1 small crystals, but this method not only caused the problem of difficult separation of molecular sieve crystals and synthesis liquid during the synthesis process, but also made the reaction process difficult. It is difficult to separate the catalyst from the reaction solution, resulting in high energy consumption. At present, in the single-pot continuous slurry bed synthesis technology of cyclohexanone oxime developed by Sinopec, the membrane microfiltration separation technology is used to separate the TS-1 crystallites and the reaction medium. However, the membrane is easily fouled during use. It needs to be cleaned and replaced from time to time, causing a lot of inconvenience to the separation process.

SUMMARY OF THE INVENTION

The invention provides a preparation method and application of a modified TS-1 catalyst.

Synthesis of TS-1 catalyst: the molar ratio of tetraethylorthosilicate (TEOS):tetrabutyl titanate (TBOT):tetrapropylammonium hydroxide (TPAOH): _H2O is 1:0.03:0.45:15.5 ; Add the mixture of 24.19g TEOS and 1.19g TBOT to 42.98g 25wt.% TPAOH aqueous solution, stir at 60°C for 3h, and drain alcohol at 80°C for 1h, transfer the obtained colloidal solution to 100ml stainless steel In the reaction kettle, dynamic crystallization was carried out in a homogeneous reactor for 24h (rotation rate was 25-120 rpm), after centrifugation, washing and drying, the solid powder was finally heated at a rate of 5°C/min in an air atmosphere of 550°C. After calcination for 6h, TS-1 catalyst was obtained. Synthetic methods are described in the reference (MG Clerici et al., J. Catal., 1991, 129: 157-167).

A preparation method of a modified TS-1 catalyst: take 0.2g of TS-1 catalyst and put it into a ceramic crucible and place it in a heating cavity of an ultraviolet high temperature reactor; evacuate the cavity pressure to 2Pa, and then heat it within 2min to 425°C; UV irradiation (wavelength of 200-400nm) samples for 10min, namely, the modified TS-1 catalyst is obtained.

The application of the modified TS-1 catalyst in the reaction of cyclohexanone ammoximation to prepare cyclohexanone oxime includes the following steps:

1) Add the modified TS-1 catalyst, solvent and cyclohexanone into a three-port glass reactor equipped with a reflux condensing device at one time, heat in a constant temperature water bath at 78°C, and magnetically stir the reaction mixture; wherein the TS-1 catalyst The dosage ratio to cyclohexanone is 8g/mol; the solvent used is an equimolar mixed solution of tert-butanol and distilled water;

2) Then continuously add 30wt.% hydrogen peroxide with a constant flow sampling pump, wherein the molar ratio of hydrogen peroxide and cyclohexanone is 1.2:1, and the continuous sampling rate of hydrogen peroxide is 0.04ml/min; at the same time, 25wt.% ammonia water is added intermittently, Wherein the mol ratio of ammonia water to cyclohexanone is 2:1, and the intermittent addition time interval of ammonia water is 10min;

3) After the above mixture was reacted for 3 hours, methanol was added, mixed and stirred, centrifuged, and a liquid sample was taken. Then, the conversion rate of cyclohexanone and the selectivity to cyclohexanone oxime were analyzed by gas chromatography using the internal standard method.

In the present invention, on a gas chromatography Agilent 7890B equipped with a FID detector and an HP-5 capillary column, the internal standard method is adopted with toluene as an internal standard, and the conversion rate of cyclohexanone and the selection of p-cyclohexanone oxime are calculated according to the following formulas sex:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

The invention adopts an ultraviolet high temperature treatment method to modify the TS-1 catalyst, applies the catalyst before and after modification to the reaction of cyclohexanone ammoxime synthesis to cyclohexanone oxime, and conducts XRD and SEM characterization. The results show that, compared with the traditional TS-1 catalyst, the modified TS-1 catalyst exhibits higher catalytic activity and higher selectivity to the target product cyclohexanone oxime in the ammoximation reaction of cyclohexanone. , and its crystal structure and morphology did not change before and after modification.

Description of drawings

Fig. 1 is the schematic diagram of ultraviolet high temperature reactor device

Fig. 2 is the XRD pattern of the catalyst of Example 1

Fig. 3 is the SEM spectrum of the catalyst of Example 1

Fig. 4 is the XRD pattern of the catalyst of Example 2

Fig. 5 is the SEM spectrum of the catalyst of Example 2

Fig. 6 is the XRD pattern of the catalyst of Example 3

Fig. 7 is the SEM spectrum of the catalyst of Example 3

Detailed ways

The present invention will be further described below through specific examples, but the present invention is not limited to the following examples.

Example 1

Preparation of TS-1 catalyst: According to the molar ratio of TEOS:TBOT:TPAOH:H ₂ O, it was 1:0.03:0.45:15.5; the mixed solution of 24.19g TEOS and 1.19g TBOT was added to 42.98g of 25wt.% TPAOH. In an aqueous solution, stirred at 60 ° C for 3 h, and drained alcohol at 80 ° C for 1 h, the obtained colloidal solution was transferred to a 100 ml stainless steel reaction kettle, and dynamically crystallized in a homogeneous reactor for 24 h (rotation rate: 25 rpm ), after centrifugation, washing and drying, the solid powder was finally calcined at a heating rate of 5 °C/min in an air atmosphere at 550 °C for 6 h to obtain a TS-1 catalyst.

Modification of TS-1 catalyst: take 0.2g of TS-1 catalyst into a ceramic crucible and place it in the heating chamber of the ultraviolet high temperature reactor; vacuum the chamber pressure to 2Pa, and then heat it to 425°C within 2min; use The modified TS-1 catalyst was obtained by irradiating the sample with UV light at a wavelength of 200-400 nm for 10 min.

The ultraviolet high temperature reactor is shown in FIG. 1, and the reactor is composed of an ultraviolet light source, a temperature control system and a vacuum system. The xenon lamp 1 is placed on the support frame 3. After the light generated by the xenon lamp passes through the filter, the obtained ultraviolet light is irradiated on the powder sample by the window 2; The crucible cover 7 prevents the powder sample from being drawn away by the vacuum pump 14 . The temperature control system includes a resistance heating table 5, a vacuum electric through flange 10 (integrating a pair of K-type thermocouples and a pair of power connectors) and a PID temperature control power supply, with a temperature control accuracy of ±1°C. The vacuum system includes a Pirani vacuum gauge 6 , a KF16 bellows 12 , a KF16 manual angle valve 13 and a vacuum pump 14 . In addition, the bellows valve 9 is connected to the protective gas gas path, so that the sample can be subjected to ultraviolet high temperature treatment in the protective atmosphere. The cavity of the ultraviolet high temperature reaction system and the temperature control power supply are placed on the stand 15 .

The XRD characterization results of the TS-1 catalyst before and after modification are shown in Figure 2, and the SEM characterization results are shown in Figure 3. It can be seen from the figures that the crystal structure and morphology of the catalyst before and after modification have not changed.

The modified TS-1 catalyst was used in the synthesis of cyclohexanone amidoxime to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take liquid samples, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion rate of cyclohexanone was 81.8%, and the selectivity to cyclohexanone oxime was 83.9%.

Comparative Example 1

The preparation of TS-1 catalyst is as in Example 1.

TS-1 catalyst is used in the reaction of cyclohexanone ammoxime synthesis to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take liquid samples, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion of cyclohexanone was 71.1%, and the selectivity to cyclohexanone oxime was 74.1%.

Example 2

Preparation of TS-1 catalyst: According to the molar ratio of TEOS:TBOT:TPAOH:H ₂ O, it was 1:0.03:0.45:15.5; the mixed solution of 24.19g TEOS and 1.19g TBOT was added to 42.98g of 25wt.% TPAOH. In aqueous solution, stirred at 60°C for 3h, and drained alcohol at 80°C for 1h, the obtained colloidal solution was transferred to a 100ml stainless steel reaction kettle, and dynamically crystallized in a homogeneous reactor for 24h (rotation rate was 80 rpm ), after centrifugation, washing and drying, the solid powder was finally calcined at a heating rate of 5 °C/min in an air atmosphere at 550 °C for 6 h to obtain a TS-1 catalyst.

Modification of TS-1 catalyst: take 0.2g of TS-1 catalyst into a ceramic crucible and place it in the heating chamber of the ultraviolet high temperature reactor; evacuate the chamber pressure to 2Pa, and then heat it to 425°C within 2min ; Irradiate the sample with ultraviolet rays with a wavelength of 200-400 nm for 10 min, to obtain the modified TS-1 catalyst.

The XRD characterization results of the TS-1 catalyst before and after modification are shown in Figure 4, and the SEM characterization results are shown in Figure 5. It can be seen from the figures that the crystal structure and morphology of the catalyst before and after modification have not changed.

The modified TS-1 catalyst was used in the synthesis of cyclohexanone amidoxime to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take liquid samples, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion rate of cyclohexanone was 96.4%, and the selectivity to cyclohexanone oxime was 99.9%.

Comparative Example 2

The preparation of the TS-1 catalyst is the same as that in Example 2.

TS-1 catalyst is used in the reaction of cyclohexanone ammoxime synthesis to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take a liquid sample, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with a FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion of cyclohexanone was 76.6%, and the selectivity to cyclohexanone oxime was 99.9%.

Example 3

Preparation of TS-1 catalyst: According to the molar ratio of TEOS:TBOT:TPAOH:H ₂ O, it was 1:0.03:0.45:15.5; the mixed solution of 24.19g TEOS and 1.19g TBOT was added to 42.98g of 25wt.% TPAOH. In aqueous solution, stirred at 60 °C for 3 h, and drained alcohol at 80 °C for 1 h, the obtained colloidal solution was transferred to a 100 ml stainless steel reaction kettle, and dynamically crystallized in a homogeneous reactor for 24 h (rotation speed: 120 rpm ), after centrifugation, washing and drying, the solid powder was finally calcined at a heating rate of 5 °C/min in an air atmosphere at 550 °C for 6 h to obtain a TS-1 catalyst.

Modification of TS-1 catalyst: take 0.2g of TS-1 catalyst into a ceramic crucible and place it in the heating chamber of the ultraviolet high temperature reactor; evacuate the chamber pressure to 2Pa, and then heat it to 425°C within 2min ; Irradiate the sample with ultraviolet rays with a wavelength of 200-400 nm for 10 min, to obtain the modified TS-1 catalyst.

The XRD characterization results of the TS-1 catalyst before and after modification are shown in Figure 6, and the SEM characterization results are shown in Figure 7. It can be seen from the figures that the crystal structure and morphology of the catalyst before and after modification have not changed.

The modified TS-1 catalyst was used in the reaction of cyclohexanone ammoxime synthesis to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take liquid samples, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion rate of cyclohexanone was 99.1%, and the selectivity to cyclohexanone oxime was 99.9%.

Comparative Example 3

The preparation of the TS-1 catalyst is the same as that in Example 3.

TS-1 catalyst is used in the reaction of cyclohexanone ammoxime synthesis to cyclohexanone oxime:

According to the consumption ratio of TS-1 catalyst and cyclohexanone being 8g/mol, add 0.128g TS-1 catalyst, 1.571g cyclohexanone and 5.910g solvent into 100ml three-neck glass flask equipped with a reflux condensing device. The glass flask was heated in a constant temperature water bath at 78°C, and the reaction mixture was magnetically stirred.

Continuously add 2.177g 30wt.% hydrogen peroxide to the above-mentioned three-necked flask at a flow rate of 0.04ml/min with a peristaltic pump at a molar ratio of hydrogen peroxide and cyclohexanone to be 1.2:1; add 2.40ml25wt.% ammonia water every 10min simultaneously, wherein The molar ratio of ammonia to cyclohexanone was 2:1.

Start timing by adding hydrogen peroxide to the reactor. After 3 hours of reaction, add methanol, mix and stir, centrifuge, take liquid samples, and use toluene as an internal standard on a gas chromatograph Agilent 7890B equipped with FID detector and HP-5 capillary column. Using the internal standard method, the conversion of cyclohexanone and the selectivity to cyclohexanone oxime were calculated according to the following formula:

In the formula, C ₀ , C ₁ and C ₂ are the concentration of cyclohexanone before the reaction, the concentration of cyclohexanone after the reaction and the concentration of cyclohexanone oxime, respectively.

Catalyst activity evaluation results: the conversion rate of cyclohexanone was 88.5%, and the selectivity to cyclohexanone oxime was 99.9%.

Claims (3)

1. A preparation method of a modified TS-1 catalyst is characterized by comprising the following steps: 0.2g of TS-1 catalyst is loaded into a ceramic crucible and placed in a heating cavity of an ultraviolet high-temperature reactor; vacuumizing the cavity to 2Pa, and heating to 425 ℃ within 2 min; and irradiating the sample for 10min by using ultraviolet to obtain the modified TS-1 catalyst.

2. The use of the modified TS-1 catalyst prepared by the process of claim 1 in the reaction of preparing cyclohexanone oxime by ammoximation of cyclohexanone.

3. Use according to claim 2, characterized in that it comprises the following steps:

1) adding the modified TS-1 catalyst, a solvent and cyclohexanone into a three-port glass reactor provided with a reflux condensing device at one time, heating in a constant-temperature water bath at 78 ℃, and magnetically stirring a reaction mixture; wherein the dosage ratio of the modified TS-1 catalyst to cyclohexanone is 8g/mol, and the solvent is an equimolar mixed solution of tert-butyl alcohol and distilled water;

2) and then continuously adding 30 wt.% of hydrogen peroxide by using a constant-current sample injection pump, wherein the molar ratio of hydrogen peroxide to cyclohexanone is 1.2: 1, the continuous feeding rate of hydrogen peroxide is 0.04 ml/min; and simultaneously adding 25 wt.% of ammonia water in a batch manner, wherein the molar ratio of the ammonia water to the cyclohexanone is 2: 1, intermittently adding ammonia water for 10 min;

3) after the mixture reacts for 3 hours, methanol is added for mixing and stirring, centrifugal separation is carried out, a liquid sample is taken, and then the conversion rate of cyclohexanone and the selectivity of cyclohexanone oxime are analyzed on a gas chromatograph by an internal standard method.

Images