Embedded metal particle catalyst, preparation method and application of catalytic synthesis of pentamethylenediamine

Abstract

The present invention discloses a catalyst for embedding metal particles, a preparation method and an application for catalytic synthesis of pentamethylenediamine. A metal precursor is added to the molecular sieve aging or crystallization process to synthesize a macroporous molecular sieve catalyst for embedding metal particles. After the synthesis, the catalyst is treated with an acid for crystallization to obtain a medium- and medium-pore molecular sieve catalyst for embedding metal particles. The present invention adopts an in-situ synthesis method to prepare a catalyst for embedding metal in a macroporous molecular sieve. Without using a structure-guiding machine, the catalyst is successfully converted into a small-pore molecular sieve, and the embedding of metal nanoparticles in the small-pore molecular sieve is achieved. The structure of the synthesized catalyst is well maintained. The catalyst is used for the decarboxylation reaction of lysine to effectively improve the production efficiency of pentamethylenediamine, shorten the reaction process time, and reduce the production cost. The industrial application prospect is broad.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis, and in particular to an embedded metal particle catalyst, a preparation method and an application of the catalyst in catalyzing the synthesis of pentamethylenediamine. Background Art

[0002] 1,5-pentanediamine, also known as cadaverine, can be polymerized with adipic acid to produce nylon 56 material. Nylon 56 material has good comprehensive properties, such as high moisture absorption and perspiration rate, good air permeability, softness and good dyeing performance, etc. It is also wear-resistant, chemical-resistant, flame-retardant and easy to process, and has a strong competitive advantage in the nylon material series. The most reported production method of 1,5-pentanediamine is biological fermentation. Nanjing University of Technology uses soybean dregs hydrolyzate to ferment and produce pentamethylenediamine (CN201810954086.X), but pentamethylenediamine is toxic to microorganisms and affects production efficiency. Shanghai Cathay Biotechnology Research and Development Center Co., Ltd. has applied for multiple patents for pentamethylenediamine biofermentation methods (CN201811506539.9, CN201710453415.8, CN201710011198.7, etc.). The patent content points out that the seed liquid of lysine decarboxylase strains is introduced into the lysine fermentation process, which effectively improves the toxicity of pentamethylenediamine to the strain. However, the biofermentation method still has great difficulties, such as low lysine decarboxylase activity, poor toxicity resistance, low product concentration, and high separation cost.

[0003] Compared with the biological fermentation decarboxylation method, the chemical decarboxylation method has obvious advantages, such as the catalyst activity is not affected by the toxicity of pentamethylenediamine and the product is easy to separate. The currently reported chemical method for preparing pentamethylenediamine has a low generation rate, the main reason for which is the low catalyst performance. Currently, there are few reported catalysts, only commercial Ru / C. The use of new preparation methods to prepare more effective catalysts will be a way to improve the selectivity of pentamethylenediamine. Encapsulating metal nanoparticles in the pores of molecular sieves by embedding can prevent metal clusters from agglomerating, thereby improving catalyst performance. For large-pore molecular sieves (12-membered ring structure), such as FAU and MOR, encapsulation can be achieved by ion exchange, impregnation or chemical vapor deposition, but small-pore molecular sieves (8-membered ring pore size) cannot be effectively encapsulated in this way. In the presence of organic structure directing agents, metal nanoparticles can be embedded in small-pore molecular sieves, but organic compounds are usually retained in the molecular sieve and need to be calcined after synthesis to be removed. The use of organic directing agents also increases environmental and economic costs. Without using an organic directing agent, the large-pore molecular sieve catalyst was successfully converted into a catalyst with small-pore molecular sieve embedded metal particles. The synthesized agent was applied to the reaction of decarboxylation of lysine to prepare pentamethylenediamine, and the yield of pentamethylenediamine was greatly improved.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides an embedded metal particle catalyst and a preparation method and application thereof, specifically a new method for catalyzing the synthesis of pentamethylenediamine using a molecular sieve catalyst embedded with metal particles. The catalyst can realize the decarboxylation reaction of lysine in a relatively short time, has a high yield of pentamethylenediamine, and has industrial application value.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preparing a catalyst containing metal particles comprises adding a metal precursor into the aging or crystallization process of a molecular sieve to synthesize a macroporous molecular sieve catalyst containing metal particles, and then treating the catalyst with an acid to obtain a medium- and small-pore molecular sieve catalyst containing metal particles.

[0008] In a preferred embodiment, the embedded metal particle catalyst refers to metal particles embedded in a molecular sieve.

[0009] In a preferred embodiment, the molecular sieve pores include any one of MFI, GIS, FAU, and LTA.

[0010] In a preferred embodiment, the molecular sieve has an atomic silicon to aluminum ratio of 1-20, preferably 2-10.

[0011] In a preferred embodiment, the reactive metal particles include any one of Pd, Pt, Pb, Co, Fe, Cu, Ni, and Ru.

[0012] In a preferred embodiment, the metal precursor includes an organic metal precursor and an inorganic metal precursor.

[0013] In a preferred embodiment, the acid is one or more of citric acid, hydrochloric acid, sulfuric acid, and phosphoric acid.

[0014] In a preferred embodiment, the acid treatment conditions include a concentration of 0.05-0.1 mol / L, preferably 0.1 mol / L, a temperature of 40-180° C., a treatment time of 1-10 h, and a solid-liquid ratio of 1:5-1:20, preferably 1:10.

[0015] The present invention also provides an embedded metal particle catalyst prepared by the above method. In a preferred embodiment, the mass fraction of the metal particles in the catalyst is 0.1-20%, preferably 1%-10%.

[0016] The invention also provides the use of the embedded metal particle catalyst in the synthesis of pentamethylenediamine by decarboxylation of lysine. The synthesis of pentamethylenediamine by decarboxylation of lysine is carried out in a high-pressure reactor. Lysine or a lysine salt, water and a catalyst are placed in the high-pressure reactor to react and obtain a pentamethylenediamine aqueous solution.

[0017] In a preferred embodiment, the lysine is L-lysine, and the lysine salt is any one of lysine hydrochloride, lysine sulfate, lysine acetate, and lysine phosphate.

[0018] In a preferred embodiment, based on the mass of lysine or lysine salt solution, the amount of catalyst used is 1-60wt.%; the autoclave reaction conditions are reaction temperature 120-250°C, pressure 0.5-6 MPa, lysine or lysine salt concentration 0.01-3 M, pH value of lysine or lysine salt solution 1-8, reaction time 0-60 min, and reaction atmosphere any one of nitrogen, hydrogen, argon, helium or carbon monoxide.

[0019] The beneficial effects of the present invention are as follows: the present invention adopts an in-situ synthesis method to prepare a catalyst of a large-pore molecular sieve-embedded metal, successfully converts it into a small-pore molecular sieve, and realizes the embedding of metal nanoparticles in the small-pore molecular sieve. The metal active components of the embedded catalyst are effectively immobilized, the agglomeration of the active components is avoided, and the catalyst structure is well maintained; the use of the catalyst for the decarboxylation reaction of lysine effectively increases the production rate of pentamethylenediamine, shortens the reaction process time, reduces the production cost, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 These are the XRD test diagrams of embedded metal particle catalysts 1 to 4.

[0021] Figure 2 FI-IR images of embedded metal particle catalysts 1 to 3.

[0022] Figure 3 Graph showing the lysine conversion rate of embedded metal particle catalysts 1 to 3.

[0023] Figure 4 The selectivity graphs of pentamethylenediamine for the embedded metal particle catalysts 1 to 3 are shown.

[0024] Figure 5 The graph shows the pentamethylenediamine yield of the embedded metal particle catalysts 1 to 3. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a new method for embedding Ru@FAU catalyst, generating target topological structure molecular sieve by crystallization, and finally synthesizing Ru@NaP catalyst coated with metal particles. The crystallized catalyst is applied to the chemical lysine decarboxylation reaction, the reaction time is greatly shortened, the selectivity of pentamethylenediamine is increased, and the industrial application prospect is very broad.

[0027] Example 1

[0028] The synthesis method of the embedded metal particle catalyst in this embodiment is as follows:

[0029] 0.332g of sodium aluminate was added to sodium hydroxide solution (2.8g / 25ml) and stirred evenly, then 12.2g of silica sol was added dropwise, stirred at room temperature for 4 hours, and then 0.34g of ruthenium trichloride was added and stirred for 1h to dissolve, and then transferred to a stainless steel reactor and crystallized in a 100℃ oven for 12h. After the reaction was completed, the reactor was cooled to room temperature, the suspension was poured into a centrifuge tube, centrifuged, washed with deionized water until the pH was equal to 7, and then placed in a 100℃ oven to dry overnight to obtain the embedded metal particle catalyst 1.

[0030] Example 2

[0031] The synthesis method of the embedded metal particle catalyst in this embodiment is as follows:

[0032] 0.332g of sodium aluminate was added to sodium hydroxide solution (2.8 g / 25ml) and stirred evenly, then 12.2g of silica sol was added dropwise, stirred at room temperature for 4 hours, and then 0.34g of ruthenium trichloride was added and stirred for 1h to dissolve, and then transferred to a stainless steel reactor and crystallized in a 100℃ oven for 12h. After the reaction was completed, the reactor was cooled to room temperature, the suspension was poured into a centrifuge tube, centrifuged, washed with deionized water until the pH was equal to 7, and then placed in a 100℃ oven to dry overnight.

[0033] The dried solid powder was added into 0.05 mol / L citric acid solution with a solid-liquid ratio of 1:10 (1 g of solid powder requires 10 ml of citric acid solution), and reacted at 75°C for 2.5 h. After the reaction, it was washed with deionized water until the pH was equal to 7, and then dried in an oven at 100°C overnight to obtain the embedded metal particle catalyst 2.

[0034] Example 3

[0035] The synthesis method of the embedded metal particle catalyst in this embodiment is as follows:

[0036] 0.332g of sodium aluminate was added to sodium hydroxide solution (2.8 g / 25ml) and stirred evenly, then 12.2g of silica sol was added dropwise, stirred at room temperature for 4 hours, and then 0.34g of ruthenium trichloride was added and stirred for 1h to dissolve, and then transferred to a stainless steel reactor and crystallized in a 100℃ oven for 12h. After the reaction was completed, the reactor was cooled to room temperature, the suspension was poured into a centrifuge tube, centrifuged, washed with deionized water until the pH was equal to 7, and then placed in a 100℃ oven to dry overnight.

[0037] The dried solid powder was added to 0.1 mol / L citric acid solution with a solid-liquid ratio of 1:10, and reacted at 75°C for 2.5 h. After the reaction, it was washed with deionized water until the pH was equal to 7, and then placed in a 100°C oven to dry overnight to obtain the embedded metal particle catalyst 3.

[0038] Example 4

[0039] The synthesis method of the embedded metal particle catalyst in this embodiment is as follows:

[0040] 0.332g of sodium aluminate was added to sodium hydroxide solution (2.8g / 25 ml) and stirred evenly, then 12.2g of silica sol was added dropwise, stirred at room temperature for 4 hours, and then 0.34g of ruthenium trichloride was added and stirred for 1h to dissolve, and then transferred to a stainless steel reactor and crystallized in a 100℃ oven for 12h. After the reaction was completed, the reactor was cooled to room temperature, the suspension was poured into a centrifuge tube, centrifuged, washed with deionized water until the pH was equal to 7, and then placed in a 100℃ oven to dry overnight.

[0041] The dried solid powder was added to 0.15 mol / L citric acid solution with a solid-liquid ratio of 1:10, and reacted at 75°C for 2.5 h. After the reaction, it was washed with deionized water until the pH was equal to 7, and then placed in a 100°C oven to dry overnight to obtain the embedded metal particle catalyst 4.

[0042] 1. Structural Characterization of Encapsulated Metal Particle Catalysts (1-4)

[0043] XRD tests were performed on samples 1 to 4, and the results were as follows: Figure 1As shown in the results, it can be seen from the figure that after treatment, the molecular sieve structure in the catalyst gradually changes from FAU to P type, and the molecular sieve still maintains a complete topological structure. In Example 3, the molecular sieve structure in the catalyst is completely transformed from FAU to P type. The XRD test results of the sample in Example 4 show that the molecular sieve structure in the catalyst has not been transformed into P type. No diffraction peak corresponding to RuOx was found in the XRD diffraction peaks of all samples, which may be because the RuOx particles are small in size and have a high degree of dispersibility.

[0044] FI-IR tests were performed on samples 1 to 3, and the following results were obtained: Figure 2 The results show that the peak value in Example 1 is 572 cm -1 Corresponding to the double 6-membered ring vibration (DR6) in the FAU framework. 606 cm in Examples 2 and 3 -1 The peak can be attributed to the double 8-membered ring vibration peak (DR8). The disappearance of DR6 and the generation of DR8 in Example 3 also confirm the transformation of the FAU molecular sieve framework to the LTA molecular sieve framework in the synthesized catalyst.

[0045] 2. Application of catalyst for decarboxylation of lysine to synthesize pentamethylenediamine

[0046] The catalyst samples prepared in Examples 1-3 were placed in different reactor liners respectively, and 0.1M L-lysine solution was added and stirred until completely mixed. The amount of catalyst sample added was 1wt% of the L-lysine solution, and the pH of the mixed solution was adjusted to 2.0 with phosphoric acid; the reactor was installed, and the air in the reactor was replaced with nitrogen, and then the nitrogen was replaced with hydrogen. After the replacement was completed, the pressure was increased to 2 MPa; the reactor was opened and reacted at 200°C and a stirring speed of 800 r / min. The reaction was carried out within 0-30 min. After the reaction solution was derivatized, the concentrations of lysine and pentamethylenediamine in the post-reaction solution were detected by liquid chromatography. The results of lysine conversion rate and pentamethylenediamine selectivity are shown in Figure 3 , 4 As shown in the figure, it can be seen that the time for complete conversion of lysine in Example 3 is shorter than that in Example 1 and Example 2. The selectivity of pentamethylenediamine in Example 3 is also higher than that in Example 1 and Example 2. Pentamethylenediamine decreases after reaching the highest value, which may be due to the deamination reaction of pentamethylenediamine. Figure 5 The pentamethylenediamine yields of different examples of lysine are shown. The pentamethylenediamine yield in Example 3 reaches 1365 g / L / h / mmol cat., which is about 3 times that of Example 1.

[0047] The present invention has been described in detail above, but the present invention is not limited to the specific embodiments described herein. It is understood by those skilled in the art that other changes and modifications may be made without departing from the scope of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for preparing an embedded metal particle catalyst, characterized in that: The metal precursor is added into the molecular sieve aging or crystallization process to synthesize a macroporous molecular sieve catalyst with metal particles embedded therein, and after the synthesis, the catalyst is treated with an acid to obtain a medium- and medium-pore molecular sieve catalyst with metal particles embedded therein; The acid used in the acid treatment is one or more of citric acid, hydrochloric acid, sulfuric acid, and phosphoric acid, with a concentration of 0.05-0.1 mol / L; The temperature of the acid treatment is 40-180°C, the treatment time is 1-24 h, the solid-liquid ratio is 1:5-1:20, and the unit is g / mL; The molecular sieve pores include any one of MFI, GIS, FAU, and LTA; The metal particles include any one of Pd, Pt, Pb, Co, Fe, Cu, Ni, and Ru.

2. The method for preparing an embedded metal particle catalyst according to claim 1, characterized in that: The atomic silicon-to-aluminum ratio of the molecular sieve is 1-20.

3. The method for preparing an embedded metal particle catalyst according to claim 1, characterized in that: The metal precursor includes an organic metal precursor or an inorganic metal precursor.

4. The embedded metal particle catalyst prepared by the preparation method according to any one of claims 1 to 3, characterized in that: The mass fraction of metal particles in the catalyst is 0.1~20%.

5. Use of the embedded metal particle catalyst according to claim 4 in the decarboxylation of lysine to synthesize pentamethylenediamine, characterized in that: The decarboxylation of lysine to synthesize pentamethylenediamine is carried out in a high-pressure reactor, wherein lysine or a lysine salt, water and a catalyst are placed in the high-pressure reactor to react and obtain an aqueous solution of pentamethylenediamine.

6. The use according to claim 5, characterized in that: Based on the mass of lysine or lysine salt solution, the amount of catalyst used is 1-60wt.%; the reaction temperature is 120-250°C, the pressure is 0.5-6 MPa, the concentration of lysine or lysine salt is 0.01-3 M, the pH value of lysine or lysine salt solution is 1-8, the reaction time is 0-60 min, the reaction atmosphere is any one of nitrogen, hydrogen, argon, helium or carbon monoxide, the lysine is L-lysine, and the lysine salt is any one of lysine hydrochloride and lysine sulfate.

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