阅读说明：本技术 一种4，4′-二氨基二苯甲烷选择加氢用钌氧化铝催化剂及其制备方法与应用 (Ruthenium-aluminum oxide catalyst for selective hydrogenation of 4, 4' -diaminodiphenylmethane and preparation method and application thereof ) 是由 李小虎 张磊 李霖 曾利辉 李岳峰 曾永康 张之翔 于 2019-11-07 设计创作，主要内容包括：本发明公开一种4,4′-二氨基二苯甲烷选择加氢用钌氧化铝催化剂,所述催化剂由载体和负载在载体上的金属组分组成,所述金属组分为钌、钡和助剂,所述助剂为铂、钯、铑和镍中的至少一种,所述载体为活性氧化铝；按照重量百分比100%计,各组分的含量如下：钌1-10%,钡0.1-0.5%,助剂0.1-1%,其余为载体；同时,本发明还公开所述催化剂的制备方法及其用于4,4′-二氨基二苯甲烷催化加氢的方法。本发明提供的催化剂,含有钡,提高了催化剂的催化活性、选择性和稳定性,在用于4,4′-二氨基二苯甲烷催化加氢时,原料转化率大于95%,产品收率高,催化剂可回收利用,寿命长,能实现多次套用,绿色环保。(The invention discloses a ruthenium-alumina catalyst for selective hydrogenation of 4, 4' -diaminodiphenylmethane, which consists of a carrier and metal components loaded on the carrier, wherein the metal components comprise ruthenium, barium and an auxiliary agent, the auxiliary agent is at least one of platinum, palladium, rhodium and nickel, and the carrier is activated alumina; the content of each component is as follows according to the weight percentage of 100 percent: 1-10% of ruthenium, 0.1-0.5% of barium, 0.1-1% of auxiliary agent and the balance of carrier; meanwhile, the invention also discloses a preparation method of the catalyst and a method for applying the catalyst to catalytic hydrogenation of 4, 4' -diaminodiphenylmethane. The catalyst provided by the invention contains barium, the catalytic activity, selectivity and stability of the catalyst are improved, when the catalyst is used for catalytic hydrogenation of 4, 4' -diaminodiphenylmethane, the conversion rate of raw materials is more than 95%, the product yield is high, the catalyst can be recycled, the service life is long, repeated application can be realized, and the catalyst is green and environment-friendly.)

1. A ruthenium aluminum oxide catalyst for selective hydrogenation of 4, 4' -diaminodiphenylmethane is characterized in that: the catalyst consists of a carrier and a metal component loaded on the carrier, wherein the metal component comprises ruthenium, barium and an auxiliary agent, the auxiliary agent is at least one of platinum, palladium, rhodium and nickel, and the carrier is activated alumina; the content of each component is as follows according to the weight percentage of 100 percent: 1 to 10 percent of ruthenium, 0.1 to 0.5 percent of barium, 0.1 to 1 percent of auxiliary agent and the balance of carrier.

2. A ruthenium alumina catalyst for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 1, characterised in that: the particle diameter of the carrier is 300-800 meshes, and the specific surface area is 100-800m²/g。

3. A ruthenium alumina catalyst for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 1, characterised in that: the average grain diameter of the ruthenium is 30-50 nm.

4. Ruthenium alumina catalyst for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to any one of claims 1 to 3, characterized in that: the content of the ruthenium is 5 percent, and the content of the auxiliary agent is 0.5 percent.

5. A process for the preparation of a ruthenium alumina catalyst for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to any one of claims 1 to 3, characterised in that: the method comprises the following steps:

(1) adding the carrier into a 10-15mol/L sodium hydroxide aqueous solution, boiling for 1-2h, naturally cooling, washing with deionized water until the pH value of a washing solution is neutral, and filtering to obtain a pretreated carrier;

(2) dissolving a soluble ruthenium compound, soluble salt of barium and soluble salt of an auxiliary agent in a solvent, then adjusting the pH of the system to 2-7, and uniformly stirring to obtain a precursor solution; the solvent is water or alcohol;

(3) carrying out ultrasonic atomization on the precursor solution to obtain atomized dropping liquid, then introducing the atomized dropping liquid into a reactor containing the pretreated carrier, uniformly stirring, dipping to obtain slurry, continuously stirring for 10-20h, filtering to obtain a filter cake, and drying the filter cake; in the slurry, 5mL of precursor solution is correspondingly added into each gram of pretreated carrier;

(4) and (4) placing the product obtained in the step (3) in a tubular furnace, purging with nitrogen for 0.5h, and reacting for 4-8h at the temperature of 200-400 ℃ in a hydrogen atmosphere.

6. The process for preparing ruthenium alumina catalysts for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 5, characterized in that: and (3) adjusting the pH value of the system by using a sodium carbonate or potassium carbonate solution in the step (2).

7. The process for preparing ruthenium alumina catalysts for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 5, characterized in that: the soluble ruthenium compound is ruthenium trichloride or/and ruthenium nitrate.

8. The process for preparing ruthenium alumina catalysts for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 5, characterized in that: the soluble salt of barium and the soluble salt of the auxiliary agent are respectively corresponding chloride or nitrate.

9. The process for preparing ruthenium alumina catalysts for the selective hydrogenation of 4, 4' -diaminodiphenylmethane according to claim 5, characterized in that: the drying temperature in the step (3) is 80-120 ℃, and the drying time is 12-24 h.

10. A process for the catalytic hydrogenation of 4, 4' -diaminodiphenylmethane using a catalyst as claimed in any one of claims 1 to 3, characterised in that: the method comprises the following steps: adding 4, 4' -diaminodiphenylmethane, a catalyst and a solvent into a high-pressure reaction kettle, introducing hydrogen into the high-pressure reaction kettle, and carrying out catalytic hydrogenation reaction for 3-5h at 90-120 ℃ under 8-10MPa to obtain a hydrogenated product; wherein the mass ratio of the catalyst to the 4, 4' -diaminodiphenylmethane is (5-10): 100, respectively; the solvent is deionized water or methanol.

Technical Field

The invention belongs to the technical field of noble metal catalysts, and particularly relates to a ruthenium aluminum oxide catalyst for hydrogenation of 4, 4' -diaminodiphenylmethane, and a preparation method and application thereof.

Background

4, 4' -diaminodicyclohexylmethane (H)¹²MDA or PACM) is an important raw material for preparing a new generation of saturated polyurethane ' dicyclohexyl methane diisocyanate (HMDI) ' with excellent performance, and the H is prepared by taking 4,4 ' -diamino diphenylmethane (MDA) as a raw material and carrying out high-pressure hydrogenation under the action of a catalyst¹²MDA, then H¹²And carrying out phosgenation on the MDA to obtain the HMDI. The isocyanate has the characteristics of stable performance, strong oxidation resistance, wide application field and the like, is widely used for preparing light polyurethane coatings, paints, foamed plastics, various elastomers, adhesives, fibers, synthetic leather, paving materials and the like, and the application field relates to important departments of national economy such as spaceflight, aviation, electromechanics, ships, vehicles, civil construction, light industry, textile and the like. In recent years, market demand at home and abroad has been increasing year by year. The catalytic systems reported so far include the following: a rhodium-based catalyst; ruthenium-based catalysts and ruthenium-rhodium bimetallic catalyst systems. How to prepare and apply a proper high-efficiency catalyst and a catalyst system in a specific reaction system is always a key technology of MDA hydrogenation at present.

The polyurethane industry in China has rapidly developed in recent years, wherein the yield and the quality of monomer MDA jump the top of the world, and various phosgenation technologies are mature day by day. In order to further manufacture HMDI and meet the increasingly strong demand of high-performance and high-quality polyurethane products in China, the development of an MDA high-efficiency hydrogenation technology is urgently needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a ruthenium aluminum oxide catalyst for hydrogenation of 4, 4' -diaminodiphenylmethane, and a preparation method and application thereof.

A ruthenium-alumina catalyst for selective hydrogenation of 4, 4' -diaminodiphenylmethane is composed of a carrier and a metal component loaded on the carrier, wherein the metal component is ruthenium, barium and an auxiliary agent, the auxiliary agent is at least one of platinum, palladium, rhodium and nickel, and the carrier is activated alumina; the content of each component is as follows according to the weight percentage of 100 percent: 1 to 10 percent of ruthenium, 0.1 to 0.5 percent of barium, 0.1 to 1 percent of auxiliary agent and the balance of carrier.

Preferably, the particle size of the carrier is 300-800 meshes, and the specific surface area is 100-800m²/g。

Preferably, the average particle size of the ruthenium is 30 to 50 nm.

Preferably, the content of the ruthenium is 5%, and the content of the auxiliary agent is 0.5%.

The preparation method of the ruthenium aluminum oxide catalyst for selective hydrogenation of 4, 4' -diaminodiphenylmethane comprises the following steps:

(1) adding the carrier into a 10-15mol/L sodium hydroxide aqueous solution, boiling for 1-2h, naturally cooling, washing with deionized water until the pH value of a washing solution is neutral, and filtering to obtain a pretreated carrier;

(2) dissolving a soluble ruthenium compound, soluble salt of barium and soluble salt of an auxiliary agent in a solvent, then adjusting the pH of the system to 2-7, and uniformly stirring to obtain a precursor solution; the solvent is water or alcohol;

(3) carrying out ultrasonic atomization on the precursor solution to obtain atomized dropping liquid, then introducing the atomized dropping liquid into a reactor containing the pretreated carrier, uniformly stirring, dipping to obtain slurry, continuously stirring for 10-20h, filtering to obtain a filter cake, and drying the filter cake; in the slurry, 5mL of precursor solution is correspondingly added into each gram of pretreated carrier;

(4) and (4) placing the product obtained in the step (3) in a tubular furnace, purging with nitrogen for 0.5h, and reacting for 4-8h at the temperature of 200-400 ℃ in a hydrogen atmosphere.

Preferably, the pH of the system is adjusted in step (2) with a sodium or potassium carbonate solution.

Preferably, the soluble ruthenium compound is ruthenium trichloride or/and ruthenium nitrate.

Preferably, the soluble salt of barium and the soluble salt of the auxiliary agent are both corresponding chloride salt or nitrate salt.

Preferably, the drying temperature in the step (3) is 80-120 ℃ and the time is 12-24 h.

A method for carrying out catalytic hydrogenation on 4, 4' -diaminodiphenylmethane by using the catalyst comprises the following steps: adding 4, 4' -diaminodiphenylmethane, a catalyst and a solvent into a high-pressure reaction kettle, introducing hydrogen into the high-pressure reaction kettle, and carrying out catalytic hydrogenation reaction for 3-5h at 90-120 ℃ under 8-10MPa to obtain a hydrogenated product; wherein the mass ratio of the catalyst to the 4, 4' -diaminodiphenylmethane is (5-10): 100, respectively; the solvent is deionized water or methanol.

Preferably, the 4, 4' -diaminodiphenylmethane, the catalyst and the solvent are added into a high-pressure reaction kettle, hydrogen is introduced into the high-pressure reaction kettle, and the catalytic hydrogenation reaction is carried out for 5 hours at the temperature of 100 ℃ and under the pressure of 9MPa, so as to obtain a hydrogenated product; wherein the mass ratio of the catalyst to the 4, 4' -diaminodiphenylmethane is 10: 100.

the invention has the advantages that:

1. the catalyst provided by the invention contains barium, so that the catalytic activity, selectivity and stability of the catalyst are improved;

2. the carrier is pretreated, and the precursor solution of the metal component is uniformly dispersed on the carrier through ultrasonic atomization, so that the dispersibility and the activity of the catalyst are improved;

3. the preparation method of the invention is easy to operate, the raw materials are easy to obtain, and the large-scale industrial production is easy to realize. The prepared catalyst is convenient to recover after use, can realize the production-recovery-reproduction of noble metals, has less loss in the recovery process, and greatly reduces the production cost of the catalyst;

4. when the catalyst provided by the invention is used for catalytic hydrogenation of 4, 4' -diaminodiphenylmethane, the conversion rate of raw materials is more than 95%, the product yield is high, the cost is reduced, the catalytic hydrogenation reaction condition is mild, the steps are simple, the catalyst can be recycled, the catalyst is green and environment-friendly, and favorable conditions are provided for large-scale application of the catalyst.

5. The catalyst provided by the invention has good stability and long service life, can be reused for many times, reduces the cost problem of using the catalyst for one time, and is easy to realize industrialization.

Detailed Description