A preparation method of palladium chloride

Abstract

The present invention relates to the field of inorganic chemical technology, and in particular to a method for preparing palladium chloride. The method for preparing palladium chloride provided by the present invention comprises the following steps: first mixing a polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixture; second mixing palladium powder, the hydrochloric acid dispersant mixture, and hydrogen peroxide, and stirring to obtain a chloropalladic acid solution; evaporating and crystallizing the chloropalladic acid solution, and sintering the obtained particles to obtain the palladium chloride. The use of polyvinyl pyrrolidone as a dispersant in the present invention can effectively control grain growth, so that the particle size of the finally prepared palladium chloride is within 10 μm.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic chemical industry, in particular to a method for preparing palladium chloride. Background Art

[0002] Palladium chloride, a basic palladium salt, is widely used in catalysts, chemical reagents, and palladium powder reduction. The existing method for preparing palladium chloride involves placing sponge palladium powder with a purity greater than 99.95% into a 5-liter beaker. Three to four times the weight of the sponge palladium powder is then added with analytically pure concentrated hydrochloric acid. The solution is heated to 60-70°C, and analytically pure hydrogen peroxide is slowly added in batches at a volume of one to two times the weight of the sponge palladium powder, stirring continuously. The solution is then filtered, concentrated, and heated to evaporate until it becomes viscous. The solution is then dried in an oven, removed, and ground into a powder to obtain the palladium chloride product. However, the palladium chloride produced by this method generally has a particle size of more than 40 microns. Because this method cannot control grain growth, the particle size is relatively large, which affects the catalyst efficiency and reduction effect. Summary of the Invention

[0003] The present invention aims to provide a method for preparing palladium chloride, wherein the particle size of the palladium chloride prepared by the method is ≤10 μm.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing palladium chloride, comprising the following steps:

[0006] first mixing the polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution;

[0007] The palladium powder, the hydrochloric acid dispersant mixture and the hydrogen peroxide are mixed and stirred to obtain a chloropalladic acid solution;

[0008] The chloropalladium acid solution is evaporated and crystallized, and the obtained particles are sintered to obtain the palladium chloride.

[0009] Preferably, the mass concentration of the polyvinyl pyrrolidone solution is 8-10%;

[0010] The mass concentration of the hydrochloric acid is 30-40%.

[0011] Preferably, the mass concentration of polyvinyl pyrrolidone in the hydrochloric acid dispersant mixture is 0.1-0.2%, and the mass concentration of hydrochloric acid is 98-99%.

[0012] Preferably, the mass concentration of the hydrogen peroxide is 20% to 30%;

[0013] The mass ratio of the palladium powder, the hydrochloric acid dispersant mixed solution and the hydrogen peroxide is 1:(10-12):(5-6).

[0014] Preferably, the second mixing is to add the hydrochloric acid dispersant mixed solution to the palladium powder and then introduce hydrogen peroxide under stirring.

[0015] Preferably, the addition rate of the hydrogen peroxide is 10 to 20 mL / min.

[0016] Preferably, the stirring time is 1 to 2 hours, and the rotation speed is 100 to 150 r / min.

[0017] Preferably, the temperature of the evaporation crystallization is 130-150°C.

[0018] Preferably, the sintering temperature is 300-350° C., and the holding time is 2-3 hours.

[0019] The present invention provides a method for preparing palladium chloride, comprising the following steps: first mixing a polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixture; second mixing palladium powder, the hydrochloric acid dispersant mixture, and hydrogen peroxide, and stirring to obtain a chloropalladic acid solution; evaporating and crystallizing the chloropalladic acid solution, and sintering the obtained particles to obtain the palladium chloride. The use of polyvinyl pyrrolidone as a dispersant in the present invention can effectively control grain growth, so that the particle size of the finally prepared palladium chloride is within 10 μm. DETAILED DESCRIPTION

[0020] The present invention provides a method for preparing palladium chloride, comprising the following steps:

[0021] first mixing the polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution;

[0022] The palladium powder, the hydrochloric acid dispersant mixture and hydrogen peroxide are mixed for a second time, and stirred to obtain a chloropalladic acid solution;

[0023] The chloropalladium acid solution is evaporated and crystallized, and the obtained particles are sintered to obtain the palladium chloride.

[0024] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0025] The present invention first mixes a polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution.

[0026] In the present invention, the mass concentration of the polyvinyl pyrrolidone solution is preferably 8-10%, more preferably 9-10%. In the present invention, the polyvinyl pyrrolidone solution is preferably prepared by mixing polyvinyl pyrrolidone with hot water. In the present invention, the temperature of the hot water is preferably 50-60°C; the mixing is preferably carried out under stirring conditions. The present invention does not have any particular restrictions on the stirring process, and a process well known to those skilled in the art can be used.

[0027] In the present invention, the mass concentration of the hydrochloric acid is preferably 30-40%, more preferably 35-37%. In the present invention, the hydrochloric acid is preferably analytically pure hydrochloric acid.

[0028] In the present invention, the first mixing is preferably performed by pouring the polyvinyl pyrrolidone solution into hydrochloric acid. The present invention does not have any special limitation on the manner and condition parameters of the first mixing, and the manner and condition parameters well known to those skilled in the art can be used.

[0029] After obtaining the hydrochloric acid dispersant mixed solution, the present invention secondly mixes the palladium powder, the hydrochloric acid dispersant mixed solution and hydrogen peroxide, and stirs to obtain a chloropalladic acid solution.

[0030] In the present invention, the palladium powder is preferably sponge palladium powder with a purity greater than 99.95%.

[0031] In the present invention, the mass concentration of the hydrogen peroxide is preferably 20-30%, more preferably 25-30%.

[0032] In the present invention, the mass ratio of the palladium powder, the hydrochloric acid dispersant mixture and the hydrogen peroxide is preferably 1:(10-12):(5-6), more preferably 1:(10-10.5):(5-5.5), and most preferably 1:11:5.

[0033] In the present invention, the second mixing step preferably comprises adding the hydrochloric acid dispersant mixture to the palladium powder, and then introducing hydrogen peroxide while stirring. In the present invention, the rate of addition of the hydrogen peroxide is preferably 10 to 20 mL / min, more preferably 15 to 20 mL / min. In the present invention, the stirring speed is preferably 100 to 150 r / min, more preferably 120 to 150 r / min.

[0034] After the second mixing is completed, the stirring time is preferably 1 to 2 hours, more preferably 1.2 to 1.8 hours, and most preferably 1.4 to 1.6 hours; the stirring speed is preferably 100 to 150 r / min, more preferably 110 to 130 r / min.

[0035] After the stirring is completed, the present invention preferably further includes sequential cooling and filtration. The present invention does not have any particular limitation on the cooling process, and can be performed using a process well known to those skilled in the art while ensuring that the temperature of the reaction system is below 40° C. In the present invention, the filtration is preferably performed using a sand core filter.

[0036] After obtaining the chloropalladium acid solution, the present invention evaporates and crystallizes the chloropalladium acid solution, and sintering the obtained particles to obtain the palladium chloride.

[0037] In the present invention, the temperature of the evaporation crystallization is preferably 130-150° C., more preferably 135-140° C., and most preferably 138-142° C.; the present invention does not have any special limitation on the time of the evaporation crystallization, and the process well known to those skilled in the art is used to terminate the evaporation crystallization when the crystals form agglomerates.

[0038] After the evaporation and crystallization is completed, the present invention preferably further includes sequential drying and pulverization; the drying temperature is preferably 130-150°C, more preferably 135-145°C, and most preferably 138-142°C; the drying time is preferably 3-5 hours, more preferably 3.5-4.5 hours, and most preferably 3.8-4.2 hours. The present invention does not have any particular limitations on the pulverization process, and can be carried out using a process well known to those skilled in the art.

[0039] In the present invention, the sintering temperature is preferably 300-350°C, more preferably 310-340°C, and most preferably 320-330°C; the holding time is preferably 2-3h, more preferably 2.2-2.8h, and most preferably 2.4-2.6h.

[0040] The preparation method of palladium chloride provided by the present invention is described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1

[0042] 2 g of polyvinyl pyrrolidone and 20 g of water (water temperature is 60° C.) were mixed and dissolved under stirring to obtain a dispersant solution;

[0043] Adding the dispersant solution to 2000 g of 37% hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution;

[0044] 200 g of palladium powder was put into a reactor, and the hydrochloric acid dispersant mixture was slowly added to the reactor, and mechanical stirring was started. At the same time, the hydrogen peroxide valve was opened, and 1000 g of high-grade hydrogen peroxide was added (the addition rate of the hydrogen peroxide was 20 mL / min), and stirring was continued for 1 h to obtain a chloropalladic acid solution;

[0045] The chloropalladic acid solution was cooled to 40° C. and filtered to obtain a pure chloropalladic acid solution;

[0046] The purified chloropalladic acid solution was transferred to an evaporative crystallizer for evaporative crystallization (temperature of 150° C.). After the crystals formed agglomerates and the evaporation was terminated, the solution was transferred to a vacuum oven for drying (drying temperature of 150° C. for 3 h). The solution was then calcined in a muffle furnace at 350° C. for 2 h. The heating was stopped and the temperature was lowered to below 50° C. to obtain palladium chloride (particle size of 1 to 10 μm and palladium mass fraction of 59.6% as measured by a laser particle size analyzer).

[0047] Example 2

[0048] 5 g of polyvinyl pyrrolidone and 50 g of water (water temperature is 60° C.) were mixed and dissolved under stirring to obtain a dispersant solution;

[0049] Adding the dispersant solution to 5000 g of 37% hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution;

[0050] 500 g of palladium powder was put into a reactor, and the hydrochloric acid dispersant mixture was slowly added to the reactor, and mechanical stirring was started. At the same time, the hydrogen peroxide valve was opened, and 2500 g of high-grade hydrogen peroxide was added (the addition rate of the hydrogen peroxide was 20 mL / min), and stirring was continued for 1 h to obtain a chloropalladic acid solution;

[0051] The chloropalladic acid solution was cooled to 40° C. and filtered to obtain a pure chloropalladic acid solution;

[0052] The purified chloropalladic acid solution was transferred to an evaporative crystallizer for evaporative crystallization (temperature of 150° C.). After the crystals formed agglomerates and the evaporation was terminated, the solution was transferred to a vacuum oven for drying (drying temperature of 150° C. for 3 h). The solution was then calcined in a muffle furnace at 350° C. for 2 h. The heating was stopped and the temperature was lowered to below 50° C. to obtain palladium chloride (particle size of 1 to 10 μm and palladium mass fraction of 59.6% as measured by a laser particle size analyzer).

[0053] Example 3

[0054] 10 g of polyvinyl pyrrolidone and 100 g of water (water temperature is 60° C.) were mixed and dissolved under stirring to obtain a dispersant solution;

[0055] Adding the dispersant solution to 10,000 g of 37% hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution;

[0056] 1000 g of palladium powder was put into a reactor, and then the hydrochloric acid dispersant mixture was slowly added to the reactor, and mechanical stirring was started. At the same time, the hydrogen peroxide valve was opened, and 5000 g of high-grade hydrogen peroxide was added (the addition rate of the hydrogen peroxide was 20 mL / min), and stirring was continued for 1 h to obtain a chloropalladic acid solution;

[0057] The chloropalladic acid solution was cooled to 40° C. and filtered to obtain a pure chloropalladic acid solution;

[0058] The purified chloropalladic acid solution was transferred to an evaporative crystallizer for evaporative crystallization (temperature of 150° C.). After the crystals formed agglomerates and the evaporation was terminated, the solution was transferred to a vacuum oven for drying (drying temperature of 150° C. for 3 h). The solution was then calcined in a muffle furnace at 350° C. for 2 h. The heating was stopped and the temperature was lowered to below 50° C. to obtain palladium chloride (particle size of 1 to 10 μm and palladium mass fraction of 59.6% as measured by a laser particle size analyzer).

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A preparation method for palladium chloride, characterized in that, The following steps are involved: first mixing the polyvinyl pyrrolidone solution and hydrochloric acid to obtain a hydrochloric acid dispersant mixed solution; The palladium powder, the hydrochloric acid dispersant mixture and hydrogen peroxide are mixed for a second time, and stirred to obtain a chloropalladic acid solution; Evaporating and crystallizing the chloropalladic acid solution, and sintering the obtained particles to obtain the palladium chloride, wherein the particle size of the palladium chloride is less than 10 μm; The mass concentration of polyvinyl pyrrolidone in the hydrochloric acid dispersant mixture is 0.1-0.2%, and the mass concentration of hydrochloric acid is 98-99%; The mass concentration of the hydrogen peroxide is 20% to 30%; The mass ratio of the palladium powder, the hydrochloric acid dispersant mixture and the hydrogen peroxide is 1:(10-12):(5-6); The second mixing step comprises adding the hydrochloric acid dispersant mixture to the palladium powder and then introducing hydrogen peroxide under stirring; The rate of adding the hydrogen peroxide is 10-20 mL / min.

2. The preparation method according to claim 1, wherein The mass concentration of the polyvinyl pyrrolidone solution is 8-10%; The mass concentration of the hydrochloric acid is 30-40%.

3. The preparation method according to claim 1, wherein The stirring time is 1 to 2 hours, and the rotation speed is 100 to 150 r / min.

4. The preparation method according to claim 1, wherein The temperature of the evaporation crystallization is 130-150°C.

5. The preparation method according to claim 1, wherein The sintering temperature is 300-350° C., and the heat preservation time is 2-3 hours.