A method and device for preparing high-purity palladium acetate

Abstract

The present application discloses a method and device for preparing high-purity palladium acetate, which uses halogen-free palladium salt crystals as a precursor, acetic acid as a solvent and ligand for the reaction, and generates palladium acetate by contacting acetic acid with palladium salt under high temperature conditions, crystallizing under low temperature conditions to obtain crude palladium acetate, and purifying to obtain high-purity palladium acetate; the preparation device is connected to a reactor through the lower end of an acetic acid storage tank, the reactor is connected to a condenser through a sand filter membrane, the condenser is connected to an acetic acid recovery tank through a sand filter membrane, the acetic acid recovery tank is connected to an acetic acid pumper through a pipeline, and the acetic acid pumper is connected to an acetic acid storage tank. The method and device for preparing palladium acetate provided by the present invention can realize semi-continuous production; not only the product yield is high, but also the amount of acetic acid used can be greatly reduced, and the emission of VOCs in the production process can be reduced. The palladium acetate prepared by the present invention has the advantages of less acetic acid residue, no nitro and hydroxyl substitution products, and no polymer palladium acetate.

Description

Technical Field

[0001] The present application relates to the field of preparation of noble metal homogeneous catalysts, and in particular to a method and device for preparing high-purity palladium acetate. Background Art

[0002] Palladium acetate, also known as palladium acetate, is an important precious metal catalyst that can be widely used to induce or catalyze various types of organic synthesis reactions. There are roughly three types of reactions in which it participates: ① Pd(II) activates olefins by coordinating with olefins, which are then attacked by nucleophiles; ② Activates the CH bonds of aromatic hydrocarbons, benzyl groups, and allyl groups; ③ As a precursor of Pd(0) reagents, low-valent Pd(0) reagents can form Pd(II)-aryl, Pd(II)-vinyl, and Pd(II)-allyl intermediates through oxidative addition with unsaturated groups, thereby activating aromatic groups, vinyl groups, and allyl chlorides or allyl acetates. These reactions have a wide range of uses in the synthesis of polymers, liquid crystal materials, functional materials, drugs, and biologically active compounds.

[0003] The existing preparation method of palladium acetate uses reagents with high corrosiveness and high cost, produces a large amount of nitrogen oxides and VOCs emissions, and has low utilization of raw materials, which does not meet the purpose of green chemical production. The prepared palladium acetate has a low yield, many nitro and hydroxyl substituted by-products, and is prone to produce insoluble polymer palladium acetate precipitation, which makes the palladium acetate purity low and the product catalytic performance poor. Therefore, it is an urgent problem to develop a low-cost, efficient, high-purity palladium acetate preparation method and production device to replace the existing preparation method. Summary of the invention

[0004] The present invention provides a method and device for preparing high-purity palladium acetate, which can not only realize the semi-continuous production of palladium acetate, but also the prepared palladium acetate has high yield, high purity and low acetic acid consumption. The method for preparing high-purity palladium acetate provided by the present invention adopts a ligand exchange technical route, and glacial acetic acid is used as both a solvent and a reactant to undergo a ligand exchange reaction with a halogen-free palladium salt to generate palladium acetate. Since the method for preparing high-purity palladium acetate provided by the present invention does not introduce nitrate and water, the prepared palladium acetate product only contains a trimer palladium acetate product without nitro and hydroxyl substitutions. Since the high-purity palladium acetate preparation device provided by the present invention organically combines the reactor, condenser, recovery and storage tanks through a pipeline / sand core filter membrane, and provides material transportation power through a pump, semi-continuous production of palladium acetate can be realized.

[0005] A method for preparing high-purity palladium acetate comprises the following steps:

[0006] (1) Under certain temperature and pressure conditions, a halogen-free palladium salt is used to react with acetic acid for a certain period of time to form palladium acetate, thereby obtaining an acetic acid solution containing palladium acetate;

[0007] (2) cooling the acetic acid solution containing palladium acetate for crystallization, separating the solid from the liquid to obtain a crude palladium acetate product, and the filtered acetic acid can be reused;

[0008] (3) At a certain temperature, the crude palladium acetate is placed in a certain amount of detergent for cleaning and purification for a certain period of time, and then filtered and vacuum dried for a certain period of time to obtain high-purity palladium acetate.

[0009] In step (1), the halogen-free palladium salt is a reaction precursor, which is selected from palladium sulfate, palladium nitrate, or a mixture of the two.

[0010] In a preferred embodiment, the halogen-free palladium salt in step (1) is palladium sulfate crystals.

[0011] In step (1), the acetic acid is glacial acetic acid, and acetic acid serves as both a solvent and a reactant.

[0012] In step (1), the initial feeding mass ratio of the halogen-free palladium salt to glacial acetic acid is 1:0.1-100, preferably 1:1-20, and more preferably 1:2-10.

[0013] In a preferred embodiment, the initial feed mass ratio of the halogen-free palladium salt to glacial acetic acid in step (1) is 1:5.

[0014] In step (1), the reaction temperature is 50 to 150°C, preferably 60 to 120°C, and more preferably 80 to 110°C.

[0015] In step (1), the reaction pressure is 0.01 to 5 MPa, preferably 0.1 to 1 MPa, and more preferably 0.1 to 0.5 MPa.

[0016] In step (1), the reaction time is 1 to 200 min, preferably 1 to 50 min, and more preferably 1 to 20 min.

[0017] In a preferred embodiment, the reaction temperature in step (1) is 95° C., the reaction pressure is 0.2 MPa, and the reaction time is 15 min.

[0018] In step (2), the cooling crystallization temperature of the acetic acid solution containing palladium acetate is 0 to 40°C, preferably 0 to 20°C.

[0019] In a preferred embodiment, the cooling crystallization temperature of the acetic acid solution containing palladium acetate in step (2) is 10°C.

[0020] In step (3), the detergent is selected from one or more mixtures of n-hexane, benzene, toluene, ethanol, methanol and water, preferably one or more mixtures of n-hexane, benzene and ethanol, and more preferably one or a mixture of n-hexane and benzene.

[0021] In a preferred embodiment, the detergent in step (3) is a mixed solution of n-hexane, benzene and toluene in a mass ratio of 1:1:1.

[0022] In step (3), the mass ratio of the crude palladium acetate to the detergent is 1:5 to 20.

[0023] In a preferred example, the mass ratio of the crude palladium acetate to the detergent is one of 1:5 to 1:14, 1:5 to 1:15, 1:5 to 1:16, 1:5 to 1:17, 1:5 to 1:18, and 1:5 to 1:20.

[0024] In a preferred example, the mass ratio of the crude palladium acetate to the detergent is one of 1:5 to 1:20, 1:6 to 1:20, 1:7 to 1:20, 1:8 to 1:20, 1:9 to 1:20, 1:10 to 1:20, 1:11 to 1:20, 1:12 to 1:20, and 1:13 to 1:20.

[0025] In step (3), the cleaning temperature is 40 to 60° C. and the cleaning time is 1 to 2 hours.

[0026] In step (3), the vacuum degree of the vacuum drying is ≤-0.09Mpa.

[0027] In step (3), the vacuum drying temperature is 60 to 120°C.

[0028] In step (3), the vacuum drying time is 0.5 to 5 hours.

[0029] According to another aspect of the present application, a device for preparing high-purity palladium acetate is provided.

[0030] Preferably, the preparation device of high-purity palladium acetate includes the following components from top to bottom: an acetic acid storage tank, a reactor, a condenser, an acetic acid recovery tank and an acetic acid pump; the lower end of the acetic acid storage tank is connected to the reactor, the reactor is connected to the condenser through a sand filter membrane, the condenser is connected to the acetic acid recovery tank through a sand filter membrane, the acetic acid recovery tank is connected to the acetic acid pump through a pipeline, and the acetic acid pump is connected to the acetic acid storage tank.

[0031] Preferably, the reactor is heated and temperature controlled by an oil bath jacket, and the condenser is cooled and temperature controlled by a water bath jacket.

[0032] Preferably, a flow needle valve is provided at the lower end of the acetic acid storage tank, and a feed port is provided on the reactor.

[0033] Preferably, the preparation device can realize semi-continuous production of palladium acetate.

[0034] The reaction pressure in the reactor of the high-purity palladium acetate preparation device is provided by an acetic acid pump.

[0035] In the device for preparing high-purity palladium acetate, the reaction time of the reactants in the reactor is determined by the pressure in the reactor and the initial feed mass of glacial acetic acid; the greater the reaction pressure and the smaller the initial feed mass of glacial acetic acid, the shorter the reaction time, and vice versa.

[0036] The high-purity palladium acetate preparation device does not require human intervention from the initial feeding to the completion of the preparation of the crude palladium acetate, so semi-continuous production of palladium acetate can be achieved.

[0037] The beneficial effects that the present invention can produce include:

[0038] 1) In the present invention, glacial acetic acid is used as both a reaction solvent and a reactant. After the two are directly heated to react, the generated solid is crystallized in a cold zone and the solid-liquid is separated. The separated acetic acid can be reused, which greatly reduces the amount of acetic acid used and reduces the emission of VOCs in the production process.

[0039] 2) In the present invention, the washing liquid after washing the crude palladium acetate can also be reused. The palladium acetate obtained after purification has no by-products such as nitro and hydroxyl substitution, and the acetic acid residue is ≤0.1%. The product yield is more than 99%.

[0040] 3) The method and device for preparing high-purity palladium acetate provided by the present invention are easy to carry out large-scale industrial production and easy to accurately control the purity and yield of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawing is a schematic structural diagram of a semi-continuous preparation reaction device of palladium acetate.

[0042] Figure numerals: 1-acetic acid storage tank; 2-flow needle valve; 3-feed port; 4-reactor; 5-sand filter membrane; 6-condenser; 7-acetic acid recovery tank; 8-acetic acid pump. DETAILED DESCRIPTION

[0043] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the palladium sulfate crystals and palladium nitrate crystals used in the present invention are purchased from Shanghai Chengqi Precious Metals Co., Ltd.; glacial acetic acid, n-hexane, benzene, toluene, ethanol, and methanol are purchased from China National Pharmaceutical Group Corporation.

[0045] The analysis method in the examples of this application is as follows:

[0046] The purity of the product palladium acetate was analyzed using Bruker's 600M liquid nuclear magnetic resonance.

[0047] The impurity element content of the product was determined using a NexIon 300Q inductively coupled plasma mass spectrometer (ICP for short) from PE Company of the United States.

[0048] Example 1 Preparation of palladium acetate using palladium sulfate crystals as raw material

[0049] Preparation of crude palladium acetate: 500g of palladium sulfate crystals are put into the reactor, 2500g of acetic acid is put into the acetic acid storage tank, the device is connected, and the device is sealed. Turn on the oil bath heating and water bath cooling devices, control the reactor temperature to 80°C, and the condenser temperature to 20°C. Turn on the acetic acid pump, acetic acid enters the reactor, adjust the flow needle valve to control the acetic acid flow rate to 500ml / min, at this time the pressure in the reactor is 0.2Mpa, and the time for acetic acid to flow through the reactor and enter the condenser is 15min. Maintain the reaction system circulation until the palladium sulfate crystals in the reactor are consumed. At this time, stop the acetic acid pump, remove the condenser, take out the crude palladium acetate obtained by the reaction, and obtain 435.9g of crude product.

[0050] Purification of palladium acetate: Place the crude palladium acetate in a 7L quartz beaker, add 3000g of a mixed solution of n-hexane, benzene and toluene in a mass ratio of 1:1:1, and stir evenly. Place the quartz beaker in a 50°C oil bath for purification for 1h. After filtration, 432.6g of palladium acetate is obtained. Place the palladium acetate in a vacuum oven at 80°C and dry it in vacuum for 2h to obtain 429.6g of the final palladium acetate product.

[0051] Quality inspection data of palladium acetate products: Liquid NMR and ICP were used to analyze palladium acetate products and impurities. The results are shown in Table 1.

[0052] Table 1 Quality inspection data of palladium acetate obtained from palladium sulfate

[0053] content(%) <![CDATA[Palladium content 2 > 47.3 <![CDATA[Content of palladium acetate trimer 1 > 99.95 <![CDATA[Content of Palladium Hydroxyacetate 1 > 0.02 <![CDATA[Content of palladium nitroacetate 2 > 0.00 <![CDATA[Acetic acid content 1 > 0.02 <![CDATA[Impurity metal content 2 > 0.01

[0054] Note: 1. By NMR 1 1. Determined by H spectrum; 2. Determined by ICP (impurities include Fe, Pt, Au, Na, Cu, Pb, Sn, Al, Si, Mg, Ca, Bi, Sb and Ag, etc.).

[0055] Example 2 Preparation of palladium acetate using palladium nitrate crystals as raw material

[0056] Preparation of crude palladium acetate: Put 500g of palladium nitrate crystals into the reactor, put 3000g of acetic acid into the acetic acid storage tank, connect the device and ensure that the device is sealed. Turn on the oil bath heating and water bath cooling devices, control the reactor temperature to 100°C, and the condenser temperature to 10°C. Turn on the acetic acid pump, acetic acid enters the reactor, adjust the flow needle valve to control the acetic acid flow rate to 200ml / min, then the pressure in the reactor is 0.5Mpa, and the time for acetic acid to flow through the reactor and enter the condenser is 20min. Maintain the reaction system circulation until the palladium sulfate crystals in the reactor are consumed. At this time, stop the acetic acid pump, remove the condenser, take out the crude palladium acetate obtained by the reaction, and obtain 452.3g of crude product.

[0057] Purification of palladium acetate: Place the crude palladium acetate in a 7L quartz beaker, add 2500g of 75wt% ethanol aqueous solution, and stir evenly. Place the quartz beaker in a 40°C oil bath for purification for 1h. After filtration, 448.7g of palladium acetate is obtained. Place the palladium acetate in a vacuum oven at 60°C and dry it in vacuum for 5h to obtain 438.7g of the final palladium acetate product.

[0058] Quality inspection data of palladium acetate products: Liquid NMR and ICP were used to analyze palladium acetate products and impurities. The results are shown in Table 2.

[0059] Table 2 Quality inspection data of palladium acetate obtained from palladium sulfate

[0060] content(%) <![CDATA[Palladium content 2 > 47.4 <![CDATA[Content of palladium acetate trimer 1 > 99.96 <![CDATA[Content of Palladium Hydroxyacetate 1 > 0.01 <![CDATA[Content of palladium nitroacetate 2 > 0.01 <![CDATA[Acetic acid content 1 > 0.01 <![CDATA[Impurity metal content 2 > 0.01

[0061] Note: 1. By NMR 1 1. Determined by H spectrum; 2. Determined by ICP (impurities include Fe, Pt, Au, Na, Cu, Pb, Sn, Al, Si, Mg, Ca, Bi, Sb and Ag, etc.).

[0062] Example 3 Preparation of palladium acetate using a mixture of palladium nitrate crystals and palladium sulfate crystals as raw materials

[0063] Preparation of crude palladium acetate: Mix 300g of palladium nitrate crystals and 300g of palladium sulfate crystals and put them into the reactor, put 4500g of acetic acid into the acetic acid storage tank, connect the device and ensure that the device is sealed. Turn on the oil bath heating and water bath cooling devices, control the reactor temperature to 110°C, and the condenser temperature to 0°C. Turn on the acetic acid pump, acetic acid enters the reactor, adjust the flow needle valve to control the acetic acid flow rate to 800ml / min, then the pressure in the reactor is 0.1Mpa, and the time for acetic acid to flow through the reactor and enter the condenser is 5min. Maintain the reaction system circulation until the palladium sulfate crystals in the reactor are consumed. At this time, stop the acetic acid pump, remove the condenser, take out the crude palladium acetate obtained by the reaction, and obtain 542.1g of crude product.

[0064] Purification of palladium acetate: Place the crude palladium acetate in a 7L quartz beaker, add 3500g of 75wt% methanol aqueous solution, and stir evenly. Place the quartz beaker in a 60°C oil bath for purification for 2h. After filtration, 538.9g of palladium acetate is obtained. Place the palladium acetate in a vacuum oven at 120°C and dry it in vacuum for 0.5h to obtain 535.7g of the final palladium acetate product.

[0065] Quality inspection data of palladium acetate product: Liquid NMR and ICP were used to analyze palladium acetate products and impurities. The results are shown in Table 3.

[0066] Table 3 Quality inspection data of palladium acetate obtained from palladium sulfate

[0067] content(%) <![CDATA[Palladium content 2 > 47.3 <![CDATA[Content of palladium acetate trimer 1 > 99.95 <![CDATA[Content of Palladium Hydroxyacetate 1 > 0.01 <![CDATA[Content of Palladium Nitroacetate 2 > 0.02 <![CDATA[Acetic acid content 1 > 0.01 <![CDATA[Impurity metal content 2 > 0.01

[0068] Note: 1. By NMR 1 1. Determined by H spectrum; 2. Determined by ICP (impurities include Fe, Pt, Au, Na, Cu, Pb, Sn, Al, Si, Mg, Ca, Bi, Sb and Ag, etc.).

[0069] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing palladium acetate, characterized in that, The following steps are involved: (1) Under certain temperature and pressure conditions, a halogen-free palladium salt is used to react with acetic acid for a certain period of time to form palladium acetate, thereby obtaining an acetic acid solution containing palladium acetate; (2) cooling the acetic acid solution containing palladium acetate to crystallize, separating the solid and the liquid to obtain a crude palladium acetate product, and the filtered acetic acid can be reused; (3) At a certain temperature, the crude palladium acetate is placed in a certain amount of detergent for washing and purification for a certain period of time, and then filtered and vacuum dried for a certain period of time to obtain palladium acetate; In step (1), the reaction temperature is 80-110° C., the reaction pressure is 0.1-0.5 MPa, and the reaction time is 1-20 min. In step (1), the halogen-free palladium salt is selected from palladium sulfate and palladium nitrate or a mixture of the two, the acetic acid is glacial acetic acid, and the mass ratio of the halogen-free palladium salt to the glacial acetic acid is 1:2-10. In step (2), the cooling crystallization temperature of the acetic acid solution containing palladium acetate is 0-20°C; In step (3), the cleaning temperature is 40-60°C, the cleaning and purification time is 1-2 h, the vacuum drying temperature is 60-120°C, and the vacuum drying time is 0.5-5 h; in step (3), the mass ratio of the crude palladium acetate to the detergent is 1:5-20, and the detergent is selected from one or more mixtures of n-hexane, benzene, toluene, ethanol, methanol and water; The preparation device adopted in the preparation method comprises the following components from top to bottom: an acetic acid storage tank, a reactor, a condenser, an acetic acid recovery tank and an acetic acid pump; the lower end of the acetic acid storage tank is connected to the reactor, the reactor is connected to the condenser through a sand filter membrane, the condenser is connected to the acetic acid recovery tank through the sand filter membrane, the acetic acid recovery tank is connected to the acetic acid pump through a pipeline, and the acetic acid pump is connected to the acetic acid storage tank.

2. A method for preparing palladium acetate according to claim 1, characterized in that: The reactor is heated and temperature controlled by an oil bath jacket, and the condenser is cooled and temperature controlled by a water bath jacket.

3. A method for preparing palladium acetate according to claim 1, characterized in that: A flow needle valve is provided at the lower end of the acetic acid storage tank, and a feed port is provided on the reactor.

4. A method for preparing palladium acetate according to claim 1, characterized in that: The preparation device can realize the semi-continuous production of palladium acetate.

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