CN106946894A - Application of the Pd radicel duplex metal catalyst in HBIW catalytic hydrogenolytic cleavages - Google Patents

Abstract

The invention discloses the application of a palladium-based bimetallic catalyst in HBIW catalytic hydrogenolysis reaction. HBIW is the intermediate product hexabenzylhexaazaisowurtzitane in the synthesis process of the energetic material CL‑20. The present invention replaces precious metals with cheap transition metals, and simultaneously uses oxides as carriers to prepare palladium-based bimetallic catalysts, and realizes the catalytic hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane, which has high catalytic activity , yield, selectivity and stability; moreover, the palladium-based bimetallic catalyst has easy access to raw materials, low content of noble metal palladium, low production cost, simple process, can effectively reduce industrial production costs, and has a good application prospect.

Description

Application of Palladium-Based Bimetallic Catalysts in HBIW Catalyzed Hydrogenolysis

technical field

The invention relates to the application of an oxide-loaded palladium-based bimetallic catalyst in the catalytic hydrogenolysis reaction of hexabenzylhexaazaisowurtzitane (HBIW).

Background technique

During the synthesis of high-density energetic material CL-20, the intermediate product hexabenzylhexaazaisowurtzitane (HBIW) is the precursor for the synthesis of high-energy density material CL-20, and its hydrogenolytic debenzylation reaction is the key to the synthesis of this compound step. However, because the cage structure of HBIW is very unstable, the hydrogenolysis reaction can only be carried out under mild conditions, so the activity of the catalyst is required to be high. The commonly used catalyst is palladium carbon catalyst. For example, the catalyst with better catalytic effect for HBIW hydrogenolysis debenzylation is Degussatype E101NE/W (US P WO 97/20785). However, palladium-carbon catalysts have problems such as high amount of precious metals, poor stability, and high production costs. Therefore, it is imminent to develop an efficient and low-cost HBIW hydrogenolysis debenzylation catalyst.

Using transition metals to partially replace palladium to prepare bimetallic catalysts is an effective method to effectively reduce palladium content while maintaining high activity. At the same time, using oxides as carriers can enhance the interaction with active components and improve catalyst performance. It is an effective way to improve the recycling performance of catalysts. These two methods can effectively reduce production costs. Many people have found that catalysts with bimetallic structures have higher hydrogenation performance than pure palladium catalysts.

At present, there have been some studies on oxide-supported palladium-based bimetallic catalysts, but they are used as oxides for hydrogenolysis and debenzylation of the intermediate product hexabenzylhexaazaisowurtzitane (HBIW) in the synthesis process of high-density energetic material CL-20. Supported palladium-based bimetallic catalysts have not been reported yet.

Contents of the invention

The technical problem actually solved by the present invention is to overcome the defect that the conventionally used catalyst in the catalytic hydrogenolysis reaction of HBIW is a precious metal palladium carbon catalyst in the prior art, resulting in higher production costs, and provides a palladium-based bimetallic catalyst in HBIW Applications in catalytic hydrogenolysis reactions. The present invention replaces noble metals with cheap transition metals, and simultaneously uses oxides as carriers to prepare palladium-based bimetallic catalysts, and realizes the catalytic hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW), which has a higher Effects on catalytic activity, yield, selectivity and stability. Moreover, the raw materials in the palladium-based bimetallic catalyst are easy to obtain, the content of noble metal palladium is low, the production cost is low, and the process is simple, which can effectively reduce the industrial production cost and has a good application prospect.

Due to the complex molecular structure of hexabenzylhexaazaisowurtzitane (HBIW), in its catalytic hydrogenolysis reaction, high temperature and acidic additives can easily cause HBIW to break the cage, and cheap transition metals to replace palladium catalysts often require higher reaction temperatures or Acid and alkali additives, it is difficult to obtain the target product when applied to HBIW hydrogenolysis reaction. The inventors of the present application discovered through creative work that a transition metal is used to replace the precious metal palladium, and an oxide is used as a carrier to prepare a bimetallic catalyst for the intermediate product hexabenzylhexabenzyl in the synthesis process of the high-density energetic material CL-20. The hydrogenolysis debenzylation reaction of azaisowutzitane (HBIW) has not yet been reported. The palladium-based bimetallic catalyst prepared in the present invention is used to catalyze the hydrogenolysis reaction of HBIW and obtains higher hydrogenolysis performance.

The present invention solves the above-mentioned technical problems through the following technical solutions.

The invention provides the application of a palladium-based bimetallic catalyst in the catalytic hydrogenolysis reaction of the intermediate product hexabenzylhexaazaisowurtzitane (HBIW) in the synthesis process of energetic material CL-20.

In the present invention, the CL-20 (hexanitrohexaazaisowurtzitane in Chinese) is a high-density energetic material with a relatively high energy level in the world.

In the present invention, the catalytic hydrogenolysis reaction of hexabenzylhexaazaisowurtzitane (HBIW) can be conventional in the field, preferably through the following steps: in a hydrogen atmosphere, the hexabenzylhexaaza Heteroisowurtzitane, DMF, acetic anhydride, bromobenzene and the palladium-based bimetallic catalyst are reacted in the first stage, and then the temperature is raised to carry out the second stage reaction until the system pressure is stable, and then filtered, washed and dried , the target product is obtained.

Wherein, the reaction formula of the catalytic hydrogenolysis reaction is as follows:

Wherein, the pressure of the hydrogen atmosphere can be conventional in the field, preferably 3-4 bar. The above pressure can be achieved by conventional methods in the art.

Wherein, the operation and conditions of the first-stage reaction can be conventional operations and conditions in the art, preferably at room temperature for 2 to 8 hours, more preferably at 15 to 30°C for 2 to 8 hours, most preferably It was reacted at 18°C for 4h.

Wherein, the amounts of the hexabenzylhexaazaisowurtzitane, the DMF, the acetic anhydride, the bromobenzene and the palladium-based bimetallic catalyst are all conventional amounts used in the art. The mass ratio of the palladium to the hexabenzylhexaazaisowurtzitane can be conventional in the field, preferably 0.00015-0.006, more preferably 0.0002-0.0045, most preferably 0.003.

Wherein, the palladium-based bimetallic catalyst can be a conventional palladium-based bimetallic catalyst in the art with oxide as a carrier and palladium and transition metal as bimetallic active components, preferably PdFe/SiO ₂ , PdFe/Al ₂ O ₃ , PdNi/TiO ₂ or PdNi/SiO ₂ . It can be prepared by conventional methods in this field, generally by surface deposition precipitation reduction method, preferably by the following steps: in the mixed solution of palladium precursor solution, transition metal precursor solution and oxide, add precipitate agent to adjust the pH value to 9-13, after the mixing reaction is complete, add a reducing agent, and after stirring, filtering, washing and drying, a palladium-based bimetallic catalyst is obtained; in the palladium-based bimetallic catalyst, the palladium and the The total load of transition metal is 0.5-20%, and the above percentage is the mass percentage of the total amount of "palladium and transition metal" in the palladium-based bimetallic catalyst.

In the preparation method of the palladium-based bimetallic catalyst, the word "precursor" is a technical term in the art, and generally refers to a form that exists before obtaining the target product, such as a palladium catalyst, and the target product is palladium hydroxide, Palladium hydroxide can be obtained by reacting H ₂ PdCl ₄ with NaOH, where H ₂ PdCl ₄ is the palladium precursor.

In the preparation method of the palladium-based bimetallic catalyst, the palladium precursor can be conventional in the field, preferably one or more of palladium chloride, chloropalladic acid, palladium bromide and palladium acetate.

In the preparation method of the palladium-based bimetallic catalyst, the transition metal can be a conventional transition metal in the art, preferably Ni, Fe, Co, Cu, Mn, Ce, Ag, Au, Zn and Cr. one or more.

In the preparation method of the palladium-based bimetallic catalyst, the total concentration of the palladium precursor solution and the transition metal precursor solution can be conventional in the field, preferably 5-50 mg/mL, more preferably 10 mg /mL.

In the preparation method of the palladium-based bimetallic catalyst, the molar ratio of the palladium to the transition metal can be any ratio, preferably (3-7):(1-7), more preferably 5: (3~5).

In the preparation method of the palladium-based bimetallic catalyst, the transition metal precursor can be conventional in the art, generally a chloride, nitrate or acetate containing a transition metal, preferably containing Ni, Fe, Co , Cu, Mn, Ce, Ag, Au, Zn and Cr chloride, nitrate or acetate of one or more transition metals, more preferably ferrous chloride, nickel nitrate, nickel chloride and One or more of ferric nitrate.

In the preparation method of the palladium-based bimetallic catalyst, the oxide can be various types of oxides conventional in the art, preferably titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide and molecular sieves. one or more of .

Wherein, the amount of the oxide can be conventional in the art, preferably 1 g/200 mL of the mixed solution.

In the preparation method of the palladium-based bimetallic catalyst, the precipitant can be a conventional precipitant in the art, preferably sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate , one or more of sodium bicarbonate and potassium bicarbonate.

In the preparation method of the palladium-based bimetallic catalyst, the operation and conditions of the mixed reaction may be conventional operations and conditions in the art. The mixing reaction time is preferably 2-48 hours. The temperature of the mixing reaction is preferably 55-65°C, more preferably 60°C.

In the preparation method of the palladium-based bimetallic catalyst, the reducing agent can be a conventional reducing agent in the art, preferably one of sodium borohydride, hydrazine hydrate, methanol, ethanol, ethylene glycol and sodium formate or Various. The amount of the reducing agent can be conventional in the field, preferably the molar ratio of the "palladium and transition metal" to the reducing agent is 1:30.

In the preparation method of the palladium-based bimetallic catalyst, the stirring operation and conditions can be conventional in the art. The stirring time is generally as long as stirring until no bubbles are generated, preferably stirring for 0.5-3 hours.

In the preparation method of the palladium-based bimetallic catalyst, the operations and conditions of the filtration, the washing and the drying can be conventional operations and conditions in the art. The drying is preferably vacuum drying at 60°C.

In the preparation method of the palladium-based bimetallic catalyst, the total loading of the palladium and the transition metal is preferably 10%-15%.

Wherein, the operation and conditions of the second-stage reaction may be conventional operations and conditions in the art, preferably at 30-40° C. for 6-20 hours.

Wherein, the stable pressure of the system generally means that hydrogen is no longer absorbed in the system.

Wherein, the operations and conditions of the filtering operation and the washing can be conventional operations and conditions in the art. The washing solvent can be conventional in the field, preferably absolute ethanol.

Wherein, the drying operation and conditions may be conventional operations and conditions in the art, preferably vacuum drying at 40-60°C.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain preferred examples of the present invention.

The reagents and raw materials used in the present invention are all commercially available.

The positive progress effect of the present invention is:

The invention applies the palladium-based bimetallic catalyst to the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW), and has higher catalytic activity, yield, selectivity and stability. Moreover, the raw materials in the palladium-based bimetallic catalyst are easy to obtain, the content of noble metal palladium is low, the production cost is low, and the process is simple, which can effectively reduce the industrial production cost and has a good application prospect.

detailed description

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples. For the experimental methods that do not specify specific conditions in the following examples, select according to conventional methods and conditions, or according to the product instructions.

Unless otherwise specified, the materials used in the following examples and comparative examples are conventional commercially available materials.

Example 1

Preparation of palladium-based bimetallic catalyst:

Put the mixed solution of 10mg/mL chloropalladium acid and ferrous chloride into 200mL water, stir evenly, then add 1.0g silicon oxide, stir for 1h, then add precipitant (sodium hydroxide), adjust the pH value to 13, in After mixing and reacting in a water bath at 60°C for 5h, add a reducing agent (sodium borohydride, the amount used is 30 times the total molar amount of palladium and iron), stir for 0.5h, filter, wash, and dry under vacuum at 60°C to obtain _SiO2 Supported Pd-Fe bimetallic catalyst, the molar ratio of palladium to iron is 1:1, and the total loading is 10%.

Hydrogenolytic debenzylation of hexabenzylhexaazaisowurtzitane (HBIW):

Put 1.0g of HBIW, 2.5mL of DMF, 1.5mL of acetic anhydride, 0.02mL of bromobenzene, and 0.05g of the above-mentioned catalyst into the reaction vessel, charge and discharge hydrogen, then charge the hydrogen to 4bar, react at 18°C for 4h, then raise the temperature to 33°C for reaction After 20 hours, filter, wash with absolute ethanol, and vacuum-dry at 40°C until constant weight.

Example 2

In the preparation process of the palladium-based bimetallic catalyst in this example, the carrier used is TiO ₂ , and other operations and parameters are the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 3

In the preparation process of the palladium-based bimetallic catalyst in this example, the carrier used was Al ₂ O ₃ , and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 4

In the preparation process of the palladium-based bimetallic catalyst in this example, the transition metal precursor used was nickel nitrate with a total loading of 10%, and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 5

In the preparation process of the palladium-based bimetallic catalyst in this example, the transition metal precursor used was nickel chloride, with a total loading of 10%, and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 6

In the preparation process of the palladium-based bimetallic catalyst in this example, the total loading of the bimetal was 0.5%, and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 7

In the preparation process of the palladium-based bimetallic catalyst in this example, the total loading of the bimetallic catalyst was 15%, and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 8

In the preparation process of the palladium-based bimetallic catalyst in this example, the total loading capacity of the bimetallic catalyst was 20%, and other operations and parameters were the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 9

In the preparation process of the palladium-based bimetallic catalyst in this example, the palladium precursor is palladium acetate, the transition metal precursor is iron nitrate, and other operations and parameters are the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Example 10

In the preparation process of the palladium-based bimetallic catalyst in this example, the precipitating agent is potassium carbonate, the reducing agent is hydrazine hydrate, and other operations and parameters are the same as in Example 1.

The operation and parameters of the hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this example are the same as those in Example 1.

Comparative example 1

In the preparation process of the catalyst of this comparative example, except that no transition metal precursor was added, other operations and parameters were the same as in Example 1.

Comparative example 2

In the preparation process of the catalyst of this comparative example, except that no transition metal precursor was added, other operations and parameters were the same as in Example 2.

Comparative example 3

In the preparation process of the catalyst of this comparative example, except that no noble metal chloropalladium acid precursor was added, other operations and parameters were the same as in Example 1.

Comparative example 4

In the preparation process of the catalyst of this comparative example, other operations and parameters were the same as those in Example 2 except that no noble metal chloropalladium acid precursor was added.

Comparative example 5

The catalyst of this comparative example is a commercially available Degussa type E101NE/W 10% Pd/C catalyst, which is used for the hydrogenolysis reaction of HBIW.

The hydrogenolysis debenzylation reaction of hexabenzylhexaazaisowurtzitane (HBIW) in this comparative example, except that the catalyst of this comparative example is used, other operations and parameters are the same as those in Example 1.

Effect Example 1

After the catalysts obtained in Examples 1-10 and Comparative Examples 1-5 are used in the hydrogenolysis and desorption reaction of HBIW, the data of the respective noble metal consumption, HBIW conversion rate and yield are shown in Table 1.

Among them, in the calculation of the yield, due to the step of "reheating" in the process of hydrogenolysis and debenzylation of HBIW, the unreacted raw material HBIW will be decomposed, so the obtained solid crude product is the difference between the actual product and the amount of catalyst. with. Therefore, the productive rate=(solid crude product-catalyst dosage)/HBIW feeding amount. The conversion rate of HBIW is obtained by analyzing and testing with a high-performance liquid chromatograph.

In Table 1, "the amount of noble metal" refers to the mass ratio of noble metal pd to HBIW in the hydrogenolysis debenzylation reaction.

Table 1

Claims (10)

1. The application of a palladium-based bimetallic catalyst in the catalytic hydrogenolysis reaction of the intermediate product hexabenzylhexaazaisowurtzitane in the energetic material CL-20 synthesis process. 2. The application according to claim 1, characterized in that, the catalytic hydrogenolysis reaction of the hexabenzylhexaazaisowurtzitane is carried out through the following steps: in a hydrogen atmosphere, the hexabenzylhexaaza Isowurtzitane, DMF, acetic anhydride, bromobenzene and the palladium-based bimetallic catalyst are reacted in the first stage, and then the temperature is raised to carry out the second stage reaction until the pressure of the system is stable, after filtering, washing and drying, The target product is obtained. 3. The application according to claim 2, characterized in that, the pressure of the hydrogen atmosphere is 3 to 4 bar; The first-stage reaction is a reaction at room temperature for 2 to 8 hours; The palladium-based bimetallic catalyst is a palladium-based bimetallic catalyst with oxide as a carrier, palladium and transition metal as bimetallic active components, preferably PdFe/SiO ₂ , PdFe/Al ₂ O ₃ , PdNi/TiO ₂ or PdNi/SiO ₂ ; the mass ratio of the palladium to the hexabenzylhexaazaisowurtzitane is 0.00015-0.006; The palladium-based bimetallic catalyst is prepared by a surface deposition precipitation reduction method; The second-stage reaction is a reaction at 30-40°C for 6-20 hours; The solvent of described washing is dehydrated alcohol; And/or, the drying is vacuum drying at 40-60°C. 4. The application according to claim 3, characterized in that, the first-stage reaction is 2-8 hours at 15-30°C, preferably 4 hours at 18°C; The mass ratio of the palladium to the hexabenzylhexaazaisowurtzitane is 0.0002-0.0045, preferably 0.003; And/or, the palladium-based bimetallic catalyst is PdFe/SiO ₂ , PdFe/Al ₂ O ₃ , PdNi/TiO ₂ or PdNi/SiO ₂ . 5. application as claimed in claim 4, is characterized in that, described palladium-based bimetallic catalyst is made through the following steps: in the mixed solution of palladium precursor solution, transition metal precursor solution and oxide compound, add precipitation agent to adjust the pH value to 9-13, after the mixing reaction is complete, add a reducing agent, and after stirring, filtering, washing and drying, a palladium-based bimetallic catalyst is obtained; in the palladium-based bimetallic catalyst, the palladium and the The total load of transition metal is 0.5-20%, and the above percentage is the mass percentage of the total amount of "palladium and transition metal" in the palladium-based bimetallic catalyst. 6. application as claimed in claim 5, is characterized in that, in the preparation method of described palladium-based bimetallic catalyst, described palladium precursor is one of palladium chloride, chloropalladic acid, palladium bromide and palladium acetate one or more kinds; In the preparation method of the palladium-based bimetallic catalyst, the transition metal is one or more of Ni, Fe, Co, Cu, Mn, Ce, Ag, Au, Zn and Cr; In the preparation method of the palladium-based bimetallic catalyst, the total concentration of the palladium precursor solution and the transition metal precursor solution is 5-50mg/mL10; In the preparation method of the palladium-based bimetallic catalyst, the molar ratio of the palladium to the transition metal is (3-7): (1-7); And/or, in the preparation method of the palladium-based bimetallic catalyst, the transition metal precursor is chloride, nitrate or acetate containing transition metal. 7. application as claimed in claim 6, is characterized in that, in the preparation method of described palladium-based bimetallic catalyst, the total concentration of described palladium precursor solution and described transition metal precursor solution is 10mg/mL; In the preparation method of the palladium-based bimetallic catalyst, the molar ratio of the palladium to the transition metal is 5: (3-5); And/or, in the preparation method of the palladium-based bimetallic catalyst, the transition metal precursor contains one or more of Ni, Fe, Co, Cu, Mn, Ce, Ag, Au, Zn and Cr Chlorides, nitrates or acetates of transition metals. 8. application as claimed in claim 7, is characterized in that, in the preparation method of described palladium-based bimetallic catalyst, described transition metal precursor is ferrous chloride, nickel nitrate, nickel chloride and ferric nitrate one or more. 9. application as claimed in claim 5, is characterized in that, in the preparation method of described palladium-based bimetallic catalyst, described oxide is titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide and molecular sieve one or more; In the preparation method of the palladium-based bimetallic catalyst, the consumption of the oxide is 1g/200mL mixed solution; And/or, in the preparation method of described palladium-based bimetallic catalyst, the precipitation agent is sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate one or more of. 10. The application according to claim 5, characterized in that, in the preparation method of the palladium-based bimetallic catalyst, the time of the mixed reaction is 2 to 48 hours; the temperature of the mixed reaction is 55 to 65°C, Preferably 60°C; In the preparation method of the palladium-based bimetallic catalyst, the reducing agent is one or more of sodium borohydride, hydrazine hydrate, methanol, ethanol, ethylene glycol and sodium formate; In the preparation method of the palladium-based bimetallic catalyst, the molar ratio of the "palladium and transition metal" to the reducing agent is 1:30; In the preparation method of the palladium-based bimetallic catalyst, the drying is vacuum drying at 60°C; And/or, in the preparation method of the palladium-based bimetallic catalyst, the total loading of the palladium and the transition metal is 10%-15%.