阅读说明：本技术 一种乙苯和乙醇为原料一步法制备二乙烯苯的方法 (Method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials through one-step method ) 是由 沈灵沁 曹文涛 熊雄 于 2020-03-26 设计创作，主要内容包括：本发明属于催化化学技术领域,涉及多功能复合催化剂的应用,尤其涉及一种乙苯和乙醇为原料一步法制备二乙烯苯的方法。复合催化剂由具有择形烷基化功能的K/ZSM-5分子筛催化剂和具有脱氢功能的纳米NiFe<Sub>2</Sub>O<Sub>4</Sub>负载Pd粒子复合而成。在惰性气体的氛围下,将乙苯和乙醇通入固定床反应器中,复合催化剂在两个床层中进行催化反应,K/ZSM-5分子筛置于第一床层,纳米NiFe<Sub>2</Sub>O<Sub>4</Sub>负载Pd粒子置于第二床层,在两个床层之间设有惰性材料；设置反应温度、反应压力和空速,反应结束后,冷凝得到二乙烯苯。整个催化反应具有能耗低、活性高、乙苯转化率高、对位二乙烯苯含量高等特点。(The invention belongs to the technical field of catalytic chemistry, relates to application of a multifunctional composite catalyst, and particularly relates to a method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials through a one-step method. The composite catalyst consists of K/ZSM-5 molecular sieve catalyst with shape selective alkylation function and nanometer NiFe with dehydrogenation function 2 O 4 Loaded Pd particles are compounded. Under the atmosphere of inert gas, introducing ethylbenzene and ethanol into a fixed bed reactor, carrying out catalytic reaction on a composite catalyst in two bed layers, placing a K/ZSM-5 molecular sieve in a first bed layer, and placing nano NiFe 2 O 4 The loaded Pd particles are arranged on a second bed layer, and an inert material is arranged between the two bed layers; setting reaction temperature, reaction pressure and airspeed, and condensing to obtain divinylbenzene after the reaction is finished. The whole catalytic reaction has the characteristics of low energy consumption, high activity, high ethylbenzene conversion rate, high para-divinylbenzene content and the like.)

1. A method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials in a one-step method is characterized by comprising the following steps:

1) sequentially filling a catalyst 1 in two beds of a fixed bed reactor: K/ZSM-5 molecular sieve, catalyst 2: nano NiFe₂O₄Supporting Pd particles; inert materials are arranged between the two bed layers;

2) and (2) introducing ethylbenzene and ethanol into the fixed bed reactor in an inert gas atmosphere, setting reaction temperature, reaction pressure and airspeed, and condensing to obtain divinylbenzene after the reaction is finished.

2. The method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials according to claim 1, wherein in the step 1), the catalyst 1 and the catalyst 2 are both solid particles, and are tableted and granulated, the particle size is 20 meshes, and the volume ratio of the catalyst 1 to the catalyst 2 is 1: 1.

3. the method for preparing divinylbenzene according to claim 1, wherein the inert material in step 1) is one of inert alumina, quartz sand, glass beads and ceramic balls, the filling height is greater than 50mm, and the particle diameter is phi 3 mm.

4. The method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials in a one-step method according to claim 1, wherein in the step 1), the ratio of the catalyst 1: the preparation method of the K/ZSM-5 molecular sieve comprises the following steps:

1) mixing potassium feldspar K₂O·Al₂O₃·6SiO₂Adding fluxing agent anhydrous potassium carbonate into the powder, wherein the adding amount is based on the oxide molar ratio K of the raw materials₂O:Al₂O₃5-16, roasting for 1.5h in a muffle furnace at 850 ℃, and adding a proper silicon source to adjust to a proper silicon-aluminum-potassium ratio to obtain a roasted clinker;

2) adding a small amount of water into the roasted clinker, heating and boiling to make it into white gel, and mixing with template agent tetrapropylammonium bromide and water according to the mole composition of initial gel to obtain n (K)₂O):n(Al₂O₃):n(SiO₂):n(TPABr):n(H₂Mixing (5-16) 1, 20-50, 0.5-3.5 and 1200-3700 in proportion, adjusting the pH to 9-13 by using sulfuric acid, aging in a water bath at 65 ℃ for 4h in sequence, crystallizing at 40 ℃ for 24h, cooling to room temperature, performing suction filtration and washing, and drying in an oven at 105 ℃ for 24h to obtain molecular sieve raw powder;

3) and roasting the molecular sieve raw powder at 600 ℃ for 4h to remove the template, thereby obtaining the K/ZSM-5 molecular sieve catalyst.

5. The method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials in a one-step method according to claim 1, wherein in the step 1), the ratio of the catalyst 2: nano NiFe₂O₄Load(s)The preparation method of the Pd particles comprises the following steps:

1) using one of palladium nitrate, palladium chloride and palladium acetate as a palladium source to prepare 0.001 mol/L^–1Solution 100m L of NiFe nanoparticles₂O₄As a carrier, mixing the carrier and the precursor to obtain a mixed solution, wherein Pd and NiFe₂O₄In a molar ratio of 1:500 to 1: 1000;

2) culturing bacillus licheniformis serving as a reducing agent, and adding the cultured bacillus licheniformis into a mixed solution of a carrier and a precursor to obtain a mixed reactant, wherein the mass ratio of the bacillus licheniformis to Pd is 10: 1;

3) and (3) oscillating the mixed reactant for 2h at normal temperature, centrifugally separating the mixed reactant, removing supernatant, washing the separated thalli, and drying in vacuum to obtain the supported metal catalyst.

6. The method for preparing divinylbenzene according to claim 1, wherein in the step 2), the inert gas is nitrogen; the molar ratio of ethylbenzene to ethanol was 1: (1.2-1.6); the reaction temperature is 300-450 ℃; the reaction pressure is 0.1-0.5 MPa; the space velocity is 2-6 h^–1。

Technical Field

The invention belongs to the technical field of catalytic chemistry, relates to the application of a multifunctional composite catalyst, and particularly relates to a method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials through a one-step method.

Technical Field

In recent years, with the rapid development of polymer materials, divinylbenzene is used as a functional monomer, and the application field of divinylbenzene is expanding. The divinylbenzene molecule contains two ethenyl groups to form three isomers of ortho, meta and para. Refining divinylbenzene, improving the content of intermediate and para-position bodies in the mixture, and obtaining products with different purity grades become the main control factor of market price. The low-purity divinylbenzene can be directly used as a functional chemical crosslinking agent and can be widely applied to adhesives, professional plastics and elastomers. Divinylbenzene and styrene are cross-linked and polymerized to prepare ion exchange resin, which is also used as modified polyester resin and polystyrene resin and used as high molecular porous microsphere and engineering plastic for various special purposes. The content of o-divinylbenzene in the raw materials is required to be as low as 1 percent in the preparation process of high-end optical materials (such as lenses, contact lenses, optical instruments and the like), so that the generation of impurities can be effectively avoided, and the optical performance of the resin is ensured.

The preparation method of divinylbenzene is numerous, and the divinylbenzene is mainly prepared by a diethylbenzene dehydrogenation method in industry. The raw material diethylbenzene (mixture of ortho position, meta position and para position) is reacted under the action of catalyst to produce the target product divinylbenzene, and simultaneously a large amount of by-products of vinyltoluene, vinylethylbenzene and impurity naphthalene, etc. The purity grade of divinylbenzene is affected, and the application of divinylbenzene in high-end optical materials is severely restricted. In addition, the traditional dehydrogenation process adopts iron oxide as a main catalyst, and has the prominent problems of low single-pass conversion rate, low product selectivity and the like. In the actual production, the catalyst induction period is long, the phenomena of catalytic efficiency reduction, surface coking and the like are easy to occur in the middle and later stages of production, and a large amount of water vapor is required to be continuously added in the reaction for the regeneration of the catalyst, so that the high energy consumption is caused.

Patent CN1915941 discloses that rare earth element compound is added in a Fe-K-Ce-Mo catalytic system to catalyze diethyl benzene dehydrogenation reaction, and the catalyst has higher carbon deposition resistance, but the selectivity of the byproduct ethyl styrene is higher. Patent CN10779282A discloses a Fe-containing alloy₂O₃、K₂O、CeO₂、MoO₃、CaO、Na₂O and the like and selected from MnO₂、TiO₂、Pr₂O₃The composite catalyst of at least one or more of the above-mentioned catalysts is used for diethylbenzene dehydrogenation reaction, and the produced product has the characteristics of low mono-diene ratio and bis-diene ratio, but its reaction temperature is high, and the catalyst must be regenerated by adding water vapour. Patent CN106179348A discloses that a graphene-supported aluminum-iron-copper compound is used as a catalyst to catalyze a mixed catalytic reaction of ethylbenzene and ethanol to produce divinylbenzene, and the reaction has the characteristics of low energy consumption, high catalyst activity, good divinylbenzene selectivity and long service life, but no data related to the service life of the catalyst is found.

The existing production process has unmatched catalytic performance, production requirements and product quality, and becomes a development bottleneck and a technical barrier for high-selectivity divinylbenzene production. Therefore, the search for new processes for preparing divinylbenzene and suitable catalysts to improve the activity of the diethylbenzene dehydrogenation catalyst and reduce the content of ortho-monomers in the product is the primary research object.

Disclosure of Invention

The invention aims to provide a method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials through a one-step method, and the method can effectively reduce the content of an o-divinylbenzene monomer.

The invention is completed by the following technical scheme:

a method for preparing divinylbenzene by using ethylbenzene and ethanol as raw materials in a one-step method comprises the following steps:

1) sequentially filling a catalyst 1 in two beds of a fixed bed reactor: K/ZSM-5 molecular sieve, catalyst 2: nano NiFe₂O₄Supporting Pd particles; inert materials are arranged between the two bed layers;

2) under the atmosphere of inert gas, introducing ethylbenzene and ethanol into a fixed bed reactor, setting reaction temperature, reaction pressure and airspeed, and after the reaction is finished, condensing to obtain divinylbenzene;

in the step 1), the catalyst 1 and the catalyst 2 are both solid particles, tabletting and granulating are carried out, the particle size is 20 meshes, and the volume ratio of the catalyst 1 to the catalyst 2 is 1: 1.

in the step 1), the inert material is one of inert alumina, quartz sand, glass beads and ceramic balls, the filling height is more than 50mm, and the particle size is phi 3 mm. ,

in the step 1), the preparation method of the catalyst 1 comprises the following steps:

1) mixing potassium feldspar (K)₂O·Al₂O₃·6SiO₂) Adding fluxing agent anhydrous potassium carbonate into the powder, wherein the adding amount is based on the oxide molar ratio K of the raw materials₂O:Al₂O₃5-16, roasting for 1.5h in a muffle furnace at 850 ℃, and adding a proper silicon source to adjust to a proper silicon-aluminum-potassium ratio to obtain a roasted clinker;

2) adding a small amount of water into the roasted clinker, heating and boiling to make it into white gel, and mixing with template agent tetrapropylammonium bromide and water according to the mole composition of initial gel to obtain n (K)₂O):n(Al₂O₃):n(SiO₂):n(TPABr):n(H₂Mixing (5-16) 1, 20-50, 0.5-3.5 and 1200-3700 in proportion, adjusting the pH to 9-13 by using sulfuric acid, aging in a water bath at 65 ℃ for 4h in sequence, crystallizing at 40 ℃ for 24h, cooling to room temperature, performing suction filtration and washing, and drying in an oven at 105 ℃ for 24h to obtain molecular sieve raw powder;

3) and roasting the molecular sieve raw powder at 600 ℃ for 4h to remove the template, thereby obtaining the K/ZSM-5 molecular sieve catalyst.

In the step 1), the preparation method of the catalyst 2 comprises the following steps:

1) using one of palladium nitrate, palladium chloride and palladium acetate as a palladium source to prepare 0.001 mol/L^–1Solution 100m L of NiFe₂O₄Mixing the carrier and the precursor to obtain a mixed solution as a carrier, wherein the molar ratio of Pd to NiFe2O4 is 1: 500-1: 1000;

2) culturing bacillus licheniformis serving as a reducing agent, and adding the cultured bacillus licheniformis into a mixed solution of a carrier and a precursor to obtain a mixed reactant, wherein the mass ratio of the bacillus licheniformis to Pd is 10: 1;

3) and (3) oscillating the mixed reactant for 2h at normal temperature, centrifugally separating the mixed reactant, removing supernatant, washing the separated thalli, and drying in vacuum to obtain the supported metal catalyst.

In the step 2), the inert gas is nitrogen; the molar ratio of ethylbenzene to ethanol was 1: (1.2-1.6); the reaction temperature was 300 deg.C-450 ℃; the reaction pressure is 0.1-0.5 MPa; the space velocity is 2-6 h^–1。

The invention has the following advantages and effects:

1) the invention adopts a mixed catalyst, two bed layers are respectively filled with a catalyst 1 and a catalyst 2 in a fixed bed reactor, and alkylation and dehydrogenation serial reactions are carried out in the same reactor, so that the content of intermediate and para-position monomers of a divinylbenzene mixture is obviously improved;

2) the reaction temperature is 300-450 ℃, the reaction pressure is low pressure, no water vapor is needed to be added, and the total energy consumption of the reaction is obviously reduced;

3) the catalyst of the invention has high catalytic activity, good selectivity and high product yield.

Detailed Description

The invention is illustrated in more detail below with reference to specific examples: