阅读说明：本技术 一种高比表面积巨菌草生物炭钯基催化剂的制备方法 (Preparation method of megalophyta biological carbon palladium-based catalyst with high specific surface area ) 是由 何亮 陈瑶 关清卿 宁平 庙荣荣 于 2019-09-03 设计创作，主要内容包括：本发明公开一种高比表面积巨菌草生物炭钯基催化剂的制备方法,将巨菌草原料洗净、烘干、粉碎后在N<Sub>2</Sub>氛围下,预炭化,得到预炭化料；将预炭化料用活化剂处理后,N<Sub>2</Sub>氛围下炭化,得到炭化料；将炭化料洗涤至中性后烘干,得到黑色固体,研磨成粉末载体；粉末载体依次加入水、钯盐溶液,搅拌至水分蒸发后烘干,之后加水,搅拌后滴加NaBH<Sub>4</Sub>溶液至不再产生气泡,用去离子水洗涤数次后烘干,得到高比表面积巨菌草生物炭钯基催化剂,该催化剂应用于苯酚选择性催化加氢,最高转化率达到99.9%,环己酮选择性达到99.9%,催化剂催化效果好,催化剂制备过程简单,催化效率高,分离方便,成本低,实现了资源化利用,符合环境经济学以及绿色化学,具有良好的应用前景。(The invention discloses a preparation method of a large-specific-surface-area large-fungus-grass biochar palladium-based catalyst 2 Pre-carbonizing in an atmosphere to obtain a pre-carbonized material; treating the pre-carbonized material with an activating agent, N 2 Carbonizing in the atmosphere to obtain a carbonized material; washing the carbonized material to be neutral, drying to obtain a black solid, and grinding into a powder carrier; sequentially adding water and palladium salt solution into a powder carrier, stirring until water is evaporated, drying, adding water, stirring, and dropwise adding NaBH 4 Washing the solution for several times with deionized water until no bubbles are generated, and drying to obtain the megaterium biological carbon palladium-based catalyst with high specific surface area, wherein the catalyst is applied toThe phenol is selectively catalyzed and hydrogenated, the highest conversion rate reaches 99.9 percent, the cyclohexanone selectivity reaches 99.9 percent, the catalyst has good catalytic effect, the catalyst preparation process is simple, the catalytic efficiency is high, the separation is convenient, the cost is low, the resource utilization is realized, the environment economy and the green chemistry are met, and the catalyst has good application prospect.)

1. a preparation method of a megalophora biological carbon palladium-based catalyst with high specific surface area is characterized by comprising the following steps:

(1) Cleaning herba Jujun, oven drying, pulverizing, and adding N₂keeping the temperature of 200-500 ℃ for 2-4h in the atmosphere to obtain a pre-carbonized material; treating the pre-carbonized material with an activating agent, N₂keeping the temperature of 500-900 ℃ for 2-4h in the atmosphere to obtain a carbonized material;

(2) washing the carbonized material obtained in the step (1) to be neutral, drying to obtain black solid, and grinding the black solid into powder to obtain a powder carrier;

(3) Sequentially adding water and palladium salt solution into the powder carrier in the step (2), stirring the mixture until water is evaporated, drying, adding water with the volume 3-5 times that of the dried product, stirring, and dropwise adding NaBH₄And (3) washing the solution for a plurality of times by using deionized water until no bubbles are generated, and drying to obtain the megaterium biological carbon palladium-based catalyst with high specific surface area.

2. The preparation method of the palladium-based catalyst with high specific surface area for Megasphaera championii as claimed in claim 1, wherein the activator in step (1) comprises a solid activator and a liquid activator, the solid activator is KOH or NaOH, and the liquid activator is 25% phosphoric acid or 25% nitric acid; when the activator is a solid activator, the pre-carbonized material and the solid activator are mixed and then ground uniformly, and the mass ratio of the pre-carbonized material to the solid activator is 1: 0.2-10; when the activating agent is a liquid activating agent, the pre-carbonized material is soaked in the liquid activating agent for more than 12 hours and then taken out, and the mass ratio of the pre-carbonized material to the liquid activating agent is 1: 0.2-10.

3. The preparation method of the palladium-based catalyst with high specific surface area for Megalobatrachus communis biochar as claimed in claim 1, wherein the washing in step (2) is performed by adding dilute nitric acid, dilute hydrochloric acid and dilute sodium hydroxide solution to neutrality, and washing with deionized water after magnetically stirring for 3-12 h.

4. The preparation method of the palladium-based catalyst with high specific surface area for Megasphaera champ bio-carbon as claimed in claim 1, wherein the palladium salt solution in step (3) is palladium nitrate solution, palladium chloride solution, palladium sulfate solution or palladium acetate solution, and the concentration is 0.1-10 g/L.

5. the preparation method of the palladium-based catalyst with high specific surface area for Megasphaera champ biochar as claimed in claim 1, wherein the volume ratio of the water and the palladium salt solution added in step (3) is 1-20: 1.

6. the preparation method of the palladium-based catalyst with high specific surface area for megalophora herbecea biological carbon as claimed in claim 1, wherein the mass of palladium element in the palladium salt solution added in step (3) is 0.5-10% of the mass of the powder carrier.

7. The preparation method of the palladium-based catalyst with high specific surface area for megalophyta biochar as claimed in claim 1, wherein the step (3) is NaBH₄The concentration of the solution is 1-20 g/L.

8. The preparation method of the palladium-based catalyst with high specific surface area for the pennisetum sinese roxb bio-carbon according to claim 1, wherein the drying in the steps (2) and (3) is carried out at 50-120 ℃ for 4-24 h.

Technical Field

The invention relates to high-value utilization of biomass resources, in particular to a preparation method of a megalophora biological carbon palladium-based catalyst with a high specific surface area.

Background

cyclohexanone is colorless oily saturated cyclic ketone, is an important organic chemical raw material for producing nylon, caprolactam, hexamethylene diamine and adipic acid, is an excellent solvent and diluent for paint, printing ink, pesticides, synthetic resin and synthetic rubber, and is widely applied to the fine chemical fields of medicines, coatings, dyes and the like. In China, the cyclohexanone production industry starts along with the production development of caprolactam, the cyclohexanone in the early stage is only an intermediate product of a caprolactam process production line, the production capacity of the cyclohexanone is limited by a caprolactam synthesis device and a production technology, and only a small amount of commercial cyclohexanone is used for supplying markets. In recent years, along with the gradual expansion of the application market of cyclohexanone, many manufacturers turn to the energy-expanding transformation of cyclohexanone production devices to produce commercial cyclohexanone in large quantities, so that the commercial cyclohexanone becomes a bulk petrochemical product.

Along with the development of petroleum and coking industries, the yield of phenol rises year by year, the price of phenol tends to be stable, and the cyclohexanone is prepared by adopting a phenol hydrogenation method, so that the comprehensive utilization of phenol is favorably realized. However, cyclohexanone is easily further hydrogenated to produce cyclohexanol and like by-products, the product distribution of which is highly dependent on the type of catalyst and the nature of the support. Industrially, the preparation of cyclohexanone by a phenol hydrogenation one-step method can be divided into gas-phase hydrogenation and liquid-phase hydrogenation. Compared with a gas phase, the liquid phase hydrogenation reaction temperature is lower, the cyclohexanone quality is better, and the energy consumption is lower. The Pd-based catalyst has good performance in the preparation of cyclohexanone by phenol liquid phase hydrogenation and is widely used. The acid-base property of the carrier, the grain size and the dispersion degree of the active metal Pd have great influence on the performance of the catalyst, and further influence the distribution of products. The reported carrier is Al₂O₃、SiO₂MgO, various carbon materials, etc., but are not suitable for industrial applications due to poor sintering resistance and poor mechanical properties.

Jujun grass is a perennial gramineae upright fasciculate plant, has strong tillering capability, is one of high-yield and high-quality fungi and grass, and is known to be used for cultivating 49 edible fungi and medicinal fungi such as shiitake mushroom, ganoderma lucidum and the like by taking the Jujun grass as a culture material. Besides being used as fungus material, the said fertilizer can also be used as feed and excellent grass for water and soil conservation.

Disclosure of Invention

the invention aims to improve the waste utilization of biomass energy and provide a preparation method of a catalyst for preparing cyclohexanone by phenol liquid phase selective hydrogenation.

The invention is realized by the following technical scheme:

A preparation method of a megalophora biological carbon palladium-based catalyst with high specific surface area comprises the following steps:

(1) Cleaning herba Jujun, oven drying, pulverizing, and adding N₂Under the atmosphere, preserving heat for 2-4h at 200-500 ℃ for pre-carbonization to obtain a pre-carbonized material; treating the pre-carbonized material with an activating agent, N₂Keeping the temperature of 500-900 ℃ for 2-4h and carbonizing in the atmosphere to obtain a carbonized material;

(2) washing the carbonized material obtained in the step (1) to be neutral, drying to obtain black solid, and grinding the black solid into powder, namely the pennisetum hydridum activated carbon with high surface area, namely a powder carrier;

(3) sequentially adding water and palladium salt solution into the powder carrier in the step (2), stirring the mixture until water is evaporated, drying, adding water with the volume 3-5 times that of the dried product, stirring, and dropwise adding NaBH₄and (3) washing the solution for a plurality of times by using deionized water until no bubbles are generated, and drying to obtain the megaterium biological carbon palladium-based catalyst with high specific surface area.

The activating agent in the step (1) comprises a solid activating agent and a liquid activating agent, wherein the solid activating agent is KOH or NaOH, and the liquid activating agent is phosphoric acid with the mass fraction of 25% or nitric acid with the mass fraction of 25%; when the activator is a solid activator, the pre-carbonized material and the solid activator are mixed and then ground uniformly, and the mass ratio of the pre-carbonized material to the solid activator is 1: 0.2-10; when the activating agent is a liquid activating agent, the pre-carbonized material is soaked in the liquid activating agent for more than 12 hours and then taken out, and the mass ratio of the pre-carbonized material to the liquid activating agent is 1: 0.2-10.

and (2) the washing in the step is to add dilute nitric acid, dilute hydrochloric acid and dilute sodium hydroxide solution to be neutral, magnetically stir for 3-12h and then wash with deionized water.

the palladium salt solution in the step (3) includes, but is not limited to, a palladium nitrate solution, a palladium chloride solution, a palladium sulfate solution, a palladium acetate solution, etc., and the concentration thereof is 0.1-10 g/L.

The volume ratio of the water and the palladium salt solution added in the step (3) is 1-20: 1.

The mass of palladium element in the palladium salt solution added in the step (3) accounts for 0.5-10% of the mass of the powder carrier.

Step (3) NaBH₄The concentration of the solution is 1-20 g/L.

the drying in the step (2) and the step (3) is carried out for 4-24h at the temperature of 50-120 ℃.

The catalyst prepared by the method is put into a phenol hydrogenation reactor for reaction at the reaction temperature of 30-120 ℃ for 1-24h, and is used for catalyzing liquid-phase hydrogenation of phenol to prepare cyclohexanone, wherein the conversion rate of phenol is 99.9%, and the selectivity of cyclohexanone is 99.9%.

Compared with the prior art, the invention has the following advantages and effects:

When the supported palladium nanoparticles for catalyzing phenol liquid-phase hydrogenation are prepared, the active carbon material with high specific surface area can be prepared by only using agricultural and forestry waste pennisetum hydridum as a carrier precursor raw material through simple operation, the active carbon material is used as a catalyst carrier, the high-dispersity pennisetum hydridum supported palladium nanoparticles are prepared through a simple impregnation method, and the prepared active carbon supported palladium nanoparticles for catalyzing phenol liquid-phase hydrogenation to prepare cyclohexanone have very high catalytic activity and selectivity which can reach 99.9 percent at most.

Detailed Description

The present invention is further illustrated by the following specific examples.