阅读说明：本技术 一种负载催化剂及其制备方法和应用 (Supported catalyst and preparation method and application thereof ) 是由 赵世聪 金一丰 余江 宋明贵 向松柏 于 2019-08-26 设计创作，主要内容包括：本发明涉及一种负载催化剂及其制备方法和应用,具体涉及一种合成聚醚胺的催化剂制备、应用及回收方法,属于有机高分子化合物的制备或化学加工技术领域。本发明公开一种负载催化剂,包括活性炭载体,以及负载在载体上的稀有金属钯,钯的含量为0.4%-0.6%。本发明还公开了上述催化剂的制备方法以及在合成聚醚胺中的应用,不仅适用于大分子量的聚醚多元醇的胺化反应,尤其对于低分子量聚醚多元醇具有较高的活性和选择性。该催化剂制备工艺简单,加氢还原性高,选择性好,性能稳定,可回收重复利用,经济性好,具有优良的应用前景。(The invention relates to a supported catalyst, a preparation method and application thereof, in particular to a preparation method, application and recovery method of a catalyst for synthesizing polyether amine, belonging to the technical field of preparation or chemical processing of organic high molecular compounds. The invention discloses a supported catalyst, which comprises an active carbon carrier and rare metal palladium loaded on the carrier, wherein the content of the palladium is 0.4-0.6%. The invention also discloses a preparation method of the catalyst and application of the catalyst in synthesizing polyether amine, which is not only suitable for amination reaction of polyether polyol with large molecular weight, but also has higher activity and selectivity for polyether polyol with low molecular weight. The catalyst has the advantages of simple preparation process, high hydrogenation reducibility, good selectivity, stable performance, recoverability and reutilization, good economy and good application prospect.)

1. A supported catalyst comprising an activated carbon support, and a metal supported on the support, characterized in that: the supported metal is platinum group metal palladium with highest hydrogenation and dehydrogenation activity, the active component of the catalyst is metal palladium, and the content of palladium is 0.4-0.6wt% of the catalyst.

2. The supported catalyst of claim 1, wherein: the content of the palladium is 0.45-0.55 wt%.

3. The supported catalyst as claimed in any one of claims 1-2, wherein the activated carbon has a specific surface area of 1000-1300m ²/g and an average pore diameter of 200-300nm, and the activated carbon support is selected from one of wood charcoal, coconut charcoal and coal charcoal.

4. A process for the preparation of a supported catalyst according to any one of claims 1-2, wherein the process comprises:

(1) Pretreating the activated carbon carrier: performing acid leaching treatment on the selected coconut shell carbon in a 10-30% nitric acid solution, filtering, washing and drying, then roasting in an inert atmosphere, cooling to obtain an acid-treated carrier, wherein the roasting temperature is 200-400 ℃, and the roasting time is 3-5 hours, so as to obtain activated carbon;

(2) Impregnation and adsorption of metal salt solutions: according to the content composition of the catalyst, immersing the activated carbon carrier prepared in the step (1) into a hydrochloric acid solution of palladium chloride, adding a sodium hydroxide solution for aging after the adsorption reaches a balance, and neutralizing with hydrochloric acid to convert palladium chloride into palladium hydroxide to be deposited on the inner hole and the surface of the carrier; then drying, and finally roasting in a muffle furnace for 2-4h at the temperature of 200-300 ℃ to obtain the palladium hydroxide loaded active carbon carrier;

(3) And (3) reduction of the catalyst: immersing the activated carbon carrier obtained in the step (2) into HCHO solution for reduction at the temperature of 90 ℃, and then injecting hydrogen for reduction when the temperature is reduced to 30-50 ℃; then filtering, washing and drying are carried out to obtain the 0.5 percent palladium-carbon catalyst.

5. The application of the supported catalyst in polyether amine synthesis as claimed in claim 1, wherein polyether polyol is subjected to hydroamination reaction to synthesize polyether amine, and the specific steps are that a continuous fixed bed process is adopted, ammonia with a molar weight of 5-20 times that of polyether polyol and hydrogen with a molar weight of 0.5-10 times that of polyether polyol are introduced under the condition that the space velocity of polyether polyol is 0.2h ^-1 -2.0h ^-1, and the hydroamination reaction is performed under the action of the supported catalyst, wherein the reaction temperature is 160-.

6. The use of a supported catalyst as claimed in claim 5 in the synthesis of polyetheramines, wherein: the polyether polyol contains one of EO or PO or EO/PO skeleton and has an average molecular weight of 200-.

7. Use of a supported catalyst according to any one of claims 5 to 6 in the synthesis of polyetheramines, wherein: the catalyst with reduced activity needs to be recovered after multiple hydroammonation reactions, and is firstly incinerated and concentrated to remove carbon and organic matters, so that palladium slag is prepared: burning the waste catalyst in a muffle furnace for 4-6h, controlling the temperature at 400 ℃ for 300-.

8. use of a supported catalyst as claimed in claim 7 in the synthesis of polyetheramines, characterized in that: weighing the palladium slag, adding concentrated hydrochloric acid 9 times and concentrated nitric acid 3 times of the weight of the palladium slag into a flask, and heating in a water bath at 70-80 ℃ for reaction to completely dissolve palladium to obtain a palladium solution.

9. Use of a supported catalyst according to claim 8 in the synthesis of polyetheramines, characterized in that: slowly adding ammonia water dropwise into the solution while stirring, stopping adding when pH reaches 8.5-9, heating in 70-75 deg.C water bath, stirring for 30min, standing, and filtering; then dropwise adding an ammonium chloride solution while stirring, stopping dropwise adding when the pH value reaches 1-2, standing, filtering, washing the precipitate for multiple times by deionized water to obtain yellow crystals, drying the obtained yellow crystals, and roasting and deaminating the yellow crystals at the temperature of 600 ℃ in a muffle furnace to obtain powdery palladium chloride.

Technical Field

The invention relates to a supported catalyst, a preparation method and application thereof, in particular to a preparation method, application and recovery method of a catalyst for synthesizing polyether amine, belonging to the technical field of preparation or chemical processing of organic high molecular compounds.

Background

Polyether Amine (PEA), also known as Amine-Terminated Polyethers (Amine-Terminated Polyethers), is a compound with a polyoxyalkylene structure as a main chain and Amine groups at the ends as active functional groups. As the amido hydrogen at the tail end of the polyether amine has stronger reaction activity compared with the hydroxyl hydrogen at the tail end of the polyether amine, the polyether amine can react with various compounds, and the application range of the polyether amine in the industrial field is greatly widened. The polyether amines can be further classified into primary amine polyether amines and secondary amine polyether amines according to the number of substituted hydrogen atoms in the amine group, and the commercially common primary amine polyether amines include polyethylene oxide diamine, polypropylene oxide diamine, polyethylene oxide/polypropylene oxide diamine, and the like. By selecting different polyoxyalkyl structures, the properties of reactivity, toughness, viscosity, hydrophilicity and the like after amination are changed, and the current commercial polyether amine comprises a series of products with single function, double function and triple function and the molecular weight of 230 to 5000. The compounds are widely applied to the fields of epoxy resin curing agents, polyurethane (polyurea) industry, gasoline detergent dispersants and the like due to the excellent performance of the compounds. At present, the largest producers of the polyetheramines internationally are the Huntsman company in the United states and the BASF company in Germany, the Huntsman company and the BASF company occupy more than 90% of market share, the research and development of the polyetheramines in China is started later, and the products have larger gaps in terms of specifications, quantity and quality compared with the products abroad.

The main methods for synthesizing polyether amine include catalytic reduction amination, leaving group method, hydrolysis method and nitro end capping method, and currently, the catalytic reduction amination method is mainly used industrially, and the method is characterized in that the mixture of polyether, ammonia and hydrogen is directly subjected to catalytic reduction amination in the presence of a catalyst at a certain temperature and pressure to produce polyether amine. For polyethers of different structural distributions and molecular weights, the catalytic reductive amination method can be further divided into a batch autoclave reaction and a continuous fixed bed reaction. The continuous reaction has become a mainstream industrial process route due to the advanced process route, easy control, simple operation, high production efficiency, short production period and high product quality.

Patent CN104119239A discloses a method for producing small molecular weight polyetheramine by continuous method, which adopts a continuous method fixed bed process form, adopts a form of connecting 2-6 reactors in series, and reduces the influence of generated water on the catalyst and improves the conversion rate of the reaction by filling different raney metal catalysts and supported metal catalysts or catalysts with different nickel-cobalt contents. The temperature of each reactor is 180-240 ℃, the pressure is 11.5-19.5MPa, the molar ratio of hydroxyl contained in polyether to liquid ammonia is 1:20-80, and the molar ratio of hydroxyl contained in polyether to hydrogen is 1: 0.4-5.

The patent CN104693434A discloses a method for continuously synthesizing polyether amine by a fixed bed, which is characterized in that polyether polyol and liquid ammonia are uniformly mixed by spraying and then mixed with hydrogen, then the mixture is subjected to hydroamination reaction in a fixed bed reactor containing an activated framework nickel catalyst loaded with nickel, copper and lanthanum under the reaction conditions of the temperature of 130-280 ℃ and the pressure of 3.0-15.0MPa, the continuous discharge is carried out by gas-liquid separation, and the product is subjected to vacuum rotary evaporation, dehydration and deamination to obtain polyether amine.

The most key in the process of preparing the polyether amine is the selection and preparation of a catalyst, the most commonly used catalyst in the industry at present is a supported metal catalyst, most of which takes alumina as a carrier and takes heavy metals such as copper, chromium and nickel as main active ingredients of the catalyst.

Patent CN106957420A discloses a preparation method of alumina supported catalyst, based on the total amount of catalyst, nickel 5-15%, cobalt 5-10%, rhenium 2-10%, molybdenum 1-5%, rhenium 1-5%, and the rest is carrier γ -Al ₂ O ₃.

Patent CN102336903A discloses a preparation method of raney nickel/aluminum catalyst, wherein the nickel content in the catalyst is 85-95%, and the aluminum content is 5-15%.

The above catalyst using alumina as carrier has a general deactivation problem in the amination process, wherein the water generated in the hydroamination reaction is a key factor causing the deactivation of the catalyst, and the deactivation rate is proportional to the amount of water generated, the root cause of which is that the carrier is subject to partial or complete crystal phase transition, i.e. rehydration, during the amination process, thereby causing the reduction of the activity or deactivation of the catalyst, low durability and reduced service life.

In order to solve the problem of catalyst deactivation, in patent CN107876098, activated carbon is used to replace alumina, and organic amine is used to modify the surface of activated carbon, so as to generate amide nitrogen groups, enhance the non-polarity of the surface of the carrier, and effectively solve the problem of water deactivation of the alumina carrier, but the catalyst still has the problems of high metal loading, non-uniform dispersion and metal loss, and the cost for preparing the catalyst is also high.

The above prior art catalytic reductive amination processes all suffer from the following drawbacks: the preparation of the catalyst is quite complicated whether a batch method or a continuous method is adopted, and the catalyst is easy to inactivate and break and has short service life. The production conditions are very strict, the high-temperature and high-pressure conditions of the amination reaction have higher requirements on equipment, the product selectivity is reduced, the conversion rate is reduced, and the conditions are particularly serious for small-molecular polyether, so that the appearance color and luster are influenced, and the performance of downstream products is also influenced.

The present application was made based on this.

Disclosure of Invention

The invention aims to provide a supported catalyst for synthesizing polyetheramine, which overcomes the defect of poor hydration resistance of the existing hydroamination catalyst and has high activity and good selectivity.

in order to achieve one aspect of the above purpose, the following technical solutions are adopted in the present application:

a supported catalyst comprises an activated carbon carrier and metal loaded on the carrier, wherein the loaded metal is platinum group metal palladium with the highest hydrogenation and dehydrogenation activity, the active component of the catalyst is metal palladium, and the content of the palladium is 0.4-0.6wt% of the catalyst.

The content of the palladium is 0.45-0.55 wt%.

The specific surface area of the activated carbon is 1000-1300m ²/g, the average pore diameter is 200-300nm, and the activated carbon carrier is selected from one of wood carbon, coconut shell carbon and coal carbon.

A method of preparing a supported catalyst, the method comprising:

(1) Pretreating the activated carbon carrier: performing acid leaching treatment on the selected coconut shell carbon in a 10-30% nitric acid solution, filtering, washing and drying, then roasting in an inert atmosphere, cooling to obtain an acid-treated carrier, wherein the roasting temperature is 200-400 ℃, and the roasting time is 3-5 hours, so as to obtain activated carbon;

(2) Impregnation and adsorption of metal salt solutions: according to the content composition of the catalyst, immersing the activated carbon carrier prepared in the step (1) into a hydrochloric acid solution of palladium chloride, adding a sodium hydroxide solution for aging after the adsorption reaches a balance, and neutralizing with hydrochloric acid to convert palladium chloride into palladium hydroxide to be deposited on the inner hole and the surface of the carrier; then drying, and finally roasting in a muffle furnace for 2-4h at the temperature of 200-300 ℃ to obtain the palladium hydroxide loaded active carbon carrier;

(3) And (3) reduction of the catalyst: immersing the activated carbon carrier obtained in the step (2) into HCHO solution for reduction at the temperature of 90 ℃, and then injecting hydrogen for reduction when the temperature is reduced to 30-50 ℃; then filtering, washing and drying are carried out to obtain the 0.5 percent palladium-carbon catalyst.

The polyether polyol is used for hydro-ammoniation reaction to synthesize polyether amine, and the method specifically comprises the steps of introducing ammonia with the molar weight of 5-20 times and hydrogen with the molar weight of 0.5-10 times into a continuous fixed bed process under the condition that the space velocity of the polyether polyol is 0.2h ^-1 -2.0h ^-1, and carrying out hydro-ammoniation reaction under the action of a supported catalyst, wherein the reaction temperature is 160-200 ℃ and the reaction pressure is 6-10 MPa.

The polyether polyol contains one of EO or PO or EO/PO skeleton and has an average molecular weight of 200-.

The catalyst with reduced activity needs to be recovered after multiple hydroammonation reactions, and is firstly incinerated and concentrated to remove carbon and organic matters, so that the palladium slag is prepared.

The preparation method of the palladium slag comprises the following steps: burning the waste catalyst in a muffle furnace for 4-6h, controlling the temperature at 400 ℃ for 300-.

Weighing the palladium slag, adding concentrated hydrochloric acid 9 times and concentrated nitric acid 3 times of the weight of the palladium slag into a flask, and heating and reacting in a water bath at 70-80 ℃ to completely dissolve palladium to obtain a palladium solution.

Slowly adding ammonia water dropwise into the solution while stirring, stopping adding when pH reaches 8.5-9, heating in 70-75 deg.C water bath, stirring for 30min, standing, and filtering; then dropwise adding an ammonium chloride solution while stirring, stopping dropwise adding when the pH value reaches 1-2, standing, filtering, washing the precipitate for multiple times by deionized water to obtain yellow crystals, drying the obtained yellow crystals, and roasting and deaminating the yellow crystals at the temperature of 600 ℃ in a muffle furnace to obtain powdery palladium chloride.

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

(1) The activated carbon is used as a carrier instead of alumina, so that the problem that the alumina carrier partially or completely changes the crystal phase when meeting water in the amination process, namely, the rehydration phenomenon is avoided, and the catalytic activity and the service life of the catalyst are improved.

(2) Research finds that the catalyst is applied to the reaction of preparing polyether amine by polyether polyol, particularly the reaction of preparing polyether amine with small molecular weight (such as D230/T403 and the like), and the excellent activity is shown, and the prepared polyether amine not only has high conversion rate and high primary amine content, but also has good color and luster and high product quality.

(3) compared with the traditional Raney nickel catalyst, the palladium-carbon catalyst has the advantages of simple preparation process, lower cost, difficult poisoning, mild catalytic reaction conditions, easy regeneration, reutilization and resource saving.

Detailed Description

The present invention will be further described with reference to specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.

in the following examples, the hydroxyl number was measured by the following method: the molecular weight was calculated by referring to GB/T12008.3-2009.

Method for determining total amine value: titrating the product by adopting 0.5mol/L hydrochloric acid solution, and calculating the total amine value of the product through the volume of the consumed hydrochloric acid.

Amination conversion ═ total amine value/hydroxyl value × 100%

Method for determining secondary/tertiary amine value: and mixing and stirring the product and salicylaldehyde with equal mass for 2 hours, titrating the product by adopting 0.5mol/L hydrochloric acid solution, and calculating the sum of secondary amine and tertiary amine values of the product according to the volume of consumed hydrochloric acid.

Primary amine selectivity ═ (total amine number-secondary/tertiary amine number)/total amine number × 100%

In the following examples, the chemicals used are of analytical purity and the amounts referred to are mass amounts unless otherwise specified.