Preparation method of high-purity potassium chloroplatinite
By using potassium nitrite and reducing agent in the synthesis process of chloroplatinic acid, and controlling the reaction conditions, the purity and yield of chloroplatinic acid were successfully improved, and by-product generation and platinum in the prior art were solved. Overrestore problem.
Patent Information
- Application Number
- CN202411689199.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, when synthesizing potassium chloroplatinate, it is difficult to avoid the generation of by-products and excessive reduction of platinum, resulting in low purity and yield of chloroplatinate.
Potassium nitrite is used as the protective medium for platinum (II) ions, and is combined with a reducing agent with strong reduction ability. By controlling the reaction conditions and using saturated potassium chloride solution for concentration and crystallization, high-purity potassium chloroplatinate is prepared. .
It improves the purity and yield of chloroplatinic acid, avoids the introduction of impurities and excessive reduction of platinum, is easy to operate and does not use toxic and harmful substances.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of precious metal catalyst preparation and relates to a method for preparing high-purity potassium chloroplatinite. Background Art
[0002] Potassium chloroplatinite, also known as potassium chloroplatinite, is a dark red prismatic flaky crystal. Potassium chloroplatinite is widely used as a starting material for the manufacture of various platinum complexes and anticancer drugs, and is also used in the preparation of precious metal catalysts and precious metal coatings. The main method for synthesizing potassium chloroplatinite is to add potassium chloride solution to chloroplatinic (IV) acid solution to obtain potassium chloroplatinate, and then wash the obtained potassium chloroplatinate solid and add a reducing agent to obtain potassium chloroplatinite.
[0003] The reducing agents currently used mainly include: oxalate, hydrazine hydrate and hydrazine hydrochloride. However, different reducing agents have their own advantages and disadvantages. Oxalic acid has a relatively mild reducing property, but it will produce a byproduct of potassium bis(oxalatoplatinate), which affects the purity of potassium chloroplatinite. Although hydrazine hydrate and hydrazine hydrochloride as reducing agents do not introduce impurities, due to their strong reducing properties, potassium chloroplatinate will be excessively reduced to elemental platinum during the reaction, resulting in a decrease in the yield of potassium chloroplatinite.
[0004] Therefore, it is necessary to develop a new preparation method that can efficiently synthesize high-purity potassium chloroplatinite. Summary of the invention
[0005] In view of the above technical problems, the present invention proposes a method for preparing high-purity potassium chloroplatinite. The present invention uses potassium nitrite as a protective medium for platinum (II) ions, and compounding with a reducing agent. The reducing agent with strong reducing ability first participates in the reduction of platinum (IV) ions. Even if the reducing agent is excessive, nitrite has a strong coordination ability for platinum (II) ions and can preferentially combine with the reduced platinum (II) ions to generate Pt(NO2)4 2- , and converted to PtCl4 under acidic conditions 2- , avoiding the introduction of impurities and excessive reduction of platinum; by adding saturated potassium chloride solution and concentrating and crystallizing, potassium chloroplatinite was obtained.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions.
[0007] A method for preparing high-purity potassium chloroplatinite comprises the following steps:
[0008] Step 1, compounding potassium nitrite and a reducing agent to obtain a compound reducing agent;
[0009] Step 2, preparing chloroplatinic (II) acid solution;
[0010] Step 3, prepare potassium chloroplatinite.
[0011] Furthermore, the reducing agent is hydrazine hydrochloride.
[0012] Furthermore, the composite reducing agent is a hydrazine hydrochloride-potassium nitrite reducing agent, and its preparation method is: take an appropriate amount of potassium nitrite solid to prepare a saturated solution, take hydrazine hydrochloride and saturated potassium nitrite solution in a beaker at a volume ratio of 0.8:0.2, stir evenly, and use potassium hydroxide to control the system to be alkaline during the preparation process.
[0013] Further, the specific steps of preparing chloroplatinic (II) acid solution are:
[0014] Take 500-1000g of chloroplatinic acid solid and place it in a beaker, add 2000mL-3000mL of deionized water, stir thoroughly to completely dissolve the chloroplatinic acid solid, then transfer the beaker to a magnetic stirrer with a heating function, heat it at 70-100℃ and add a composite reducing agent to the solution under magnetic stirring until the solution turns reddish brown, then adjust the pH of the solution to acidic with a 1:1 dilute hydrochloric acid solution to remove the generated Pt(NO2)4 2- Conversion to PtCl4 2- , continue heating for 10-20 minutes to obtain chloroplatinic (II) acid solution.
[0015] Furthermore, the pH value is 1.
[0016] Further, the specific steps of preparing potassium chloroplatinite are:
[0017] The chloroplatinic acid (II) solution obtained in step 2 is heated at 70-100° C. and a saturated potassium chloride solution having an equal molar number to the platinum in the chloroplatinic acid solution is slowly added under magnetic stirring, and heating is continued for 30-50 min to obtain a potassium chloroplatinite solution. The obtained potassium chloroplatinite solution is transferred to a rotary evaporator for heating, concentration, drying and crystallization to obtain a reddish-brown potassium chloroplatinite solid.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows.
[0019] The present invention uses a reducing agent and potassium nitrite in combination to efficiently reduce a chloroplatinic acid (IV) solution to a chloroplatinic acid (II) solution, and adds a saturated potassium chloride solution to the chloroplatinic acid (II) solution to successfully prepare high-purity potassium chloroplatinite. The method improves the purity and yield of potassium chloroplatinite, does not use toxic and harmful substances, and is easy to operate.
[0020] The yield of the potassium chloroplatinite of the present invention is ≥99.5%, while that of the prior art is about 99.1%; the purity of the potassium chloroplatinite is ≥99.8%, while that of the prior art is about 99.5%; the platinum content of the potassium chloroplatinite is ≥47.8%, while that of the prior art is about 46.7%. DETAILED DESCRIPTION
[0021] The technical solution of the present invention will be described clearly and completely below. 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.
[0022] A method for preparing high-purity potassium chloroplatinite comprises the following steps:
[0023] Step 1, compounding potassium nitrite with a reducing agent: taking an appropriate amount of potassium nitrite solid to prepare a saturated solution, taking hydrazine hydrochloride and saturated potassium nitrite solution in a volume ratio of 0.8:0.2 in a beaker, stirring evenly, and using potassium hydroxide to control the system to be alkaline during the preparation process to avoid the reaction between hydrazine hydrochloride and potassium nitrite under acidic conditions;
[0024] Step 2, prepare chloroplatinic acid (II) solution: take 500-1000g of chloroplatinic acid solid and place it in a beaker, add 2000mL-3000mL of deionized water, stir well to completely dissolve the chloroplatinic acid solid, then transfer the beaker to a magnetic stirrer with a heating function, heat at 70-100°C and add a certain amount of compound reducing agent to the solution under magnetic stirring until the solution turns reddish brown, then adjust the pH of the solution to 1 with a 1:1 dilute hydrochloric acid solution to remove the generated Pt(NO2)4 2- Conversion to PtCl4 2- , continue heating for 10-20 minutes to obtain chloroplatinic acid (II) solution;
[0025] Step 3, preparing potassium chloroplatinite: heating the chloroplatinic acid (II) solution obtained in step 2 at 70-100° C. and slowly adding a saturated potassium chloride solution in an amount equal to the molar number of platinum in the chloroplatinic acid solution under magnetic stirring, and continuing heating for 30-50 min to obtain a potassium chloroplatinite solution, transferring the obtained potassium chloroplatinite solution to a rotary evaporator for heating, concentrating, drying and crystallizing to obtain a reddish-brown potassium chloroplatinite solid.
[0026] Example 1.
[0027] Take an appropriate amount of potassium nitrite solid to prepare a saturated solution, add hydrazine hydrochloride and saturated potassium nitrite solution in a beaker at a volume ratio of 0.8:0.2, stir evenly, use potassium hydroxide to control the system to be alkaline during the preparation process, and prepare hydrazine hydrochloride-potassium nitrite reducing agent.
[0028] Dissolve 500g of chloroplatinic acid solid in 2000mL of deionized water and place on a magnetic stirrer with heating function, heat at 85℃ for 15min, then slowly add 20mL of hydrochloric acid hydrazine-potassium nitrite reducing agent until the solution turns reddish brown. Then slowly add 1:1 dilute hydrochloric acid solution to the solution, accurately control the pH value of the solution to 1, until no reddish brown gas is generated. After continuing to heat for 15min, slowly add 215mL of saturated potassium chloride solution and heat for 20min, then transfer the solution to a rotary evaporator, concentrate and crystallize at 100℃ to obtain potassium chloroplatinite solid.
[0029] The yield of potassium chloroplatinite solid in Example 1 is 99.5%, the purity is 99.8%, and the platinum content is 47.8%.
[0030] Comparative example 1.
[0031] Take appropriate amounts of potassium oxalate solid and potassium nitrite solid, and prepare them into saturated solutions respectively; take the saturated potassium oxalate solution and the saturated potassium nitrite solution in a beaker with a volume ratio of 0.8:0.2, stir evenly, and use potassium hydroxide to control the system to be alkaline during the preparation process to obtain potassium oxalate-potassium nitrite reducing agent.
[0032] 500 g of chloroplatinic acid solid was dissolved in 2000 mL of deionized water and placed on a magnetic stirrer with a heating function, heated at 85°C for 15 min, then 20 mL of potassium oxalate-potassium nitrite reducing agent was slowly added until the solution turned reddish brown, then a 1:1 dilute hydrochloric acid solution was slowly added to the solution, and the pH value of the solution was accurately controlled to be 1, 3, and 5, respectively, until no reddish brown gas was generated; after continuing to heat for 15 min, 215 mL of saturated potassium chloride solution was slowly added and heated for 20 min, and then the solution was transferred to a rotary evaporator and concentrated and crystallized at 100°C to obtain potassium chloroplatinite solid.
[0033] Table 1 Potassium chloroplatinite solid analysis test results of comparative example 1
[0034] Solution pH Yield purity Pt content 1 99.2％ 99.6％ 47.1％ 3 99.1％ 99.2％ 46.9％ 5 99.0％ 99.1％ 46.8％
[0035] Comparative example 2.
[0036] Take an appropriate amount of potassium nitrite solid to prepare a saturated solution, take hydrazine hydrate and saturated potassium nitrite solution in a beaker with a volume ratio of 0.8:0.2, stir evenly, and use potassium hydroxide to control the system to be alkaline during the preparation process to obtain hydrazine hydrate-potassium nitrite reducing agent.
[0037] 500 g of chloroplatinic acid solid was dissolved in 2000 mL of deionized water and placed on a magnetic stirrer with a heating function, heated at 85 ° C for 15 minutes, and 20 mL of hydrazine hydrate-potassium nitrite reducing agent was slowly added until the solution turned reddish brown; then a 1:1 dilute hydrochloric acid solution was slowly added to the solution, and the pH value of the solution was accurately controlled to be 1, 3, and 5, respectively, until no reddish brown gas was generated; after continuing to heat for 15 minutes, 215 mL of saturated potassium chloride solution was slowly added and heated for 20 minutes, and then the solution was transferred to a rotary evaporator and concentrated and crystallized at 100 ° C to obtain potassium chloroplatinite solid.
[0038] Table 2 Potassium chloroplatinite solid analysis test results of comparative example 2
[0039] Solution pH Yield purity Pt content 1 99.4％ 99.6％ 47.2％ 3 99.2％ 99.3％ 46.9％ 5 98.9％ 99.1％ 46.6％
[0040] Comparative example 3.
[0041] Take an appropriate amount of potassium nitrite solid to prepare a saturated solution, add hydrazine hydrochloride and saturated potassium nitrite solution in a beaker at a volume ratio of 0.8:0.2, stir evenly, use potassium hydroxide to control the system to be alkaline during the preparation process, and prepare hydrazine hydrochloride-potassium nitrite reducing agent.
[0042] Dissolve 500g of chloroplatinic acid solid in 2000mL of deionized water and place it on a magnetic stirrer with heating function, heat it at 85℃ for 15min, then slowly add 20mL of hydrochloric acid hydrazine-potassium nitrite reducing agent until the solution turns reddish brown. Then slowly add a 1:1 dilute hydrochloric acid solution to the solution, and accurately control the pH value of the solution to 1, 3, and 5, respectively, until no reddish brown gas is generated. After continuing to heat for 15min, slowly add 215mL of saturated potassium chloride solution and heat for 20min, then transfer the solution to a rotary evaporator and concentrate and crystallize at 100℃ to obtain potassium chloroplatinite solid.
[0043] Table 3 Potassium chloroplatinite solid analysis test results of comparative example 3
[0044] Solution pH Yield purity Pt content 3 99.4％ 99.5％ 47.5％ 5 99.3％ 99.3％ 47.0％
[0045] Comparative example 4.
[0046] Take appropriate amounts of potassium oxalate solid and potassium nitrite solid, prepare them into saturated solutions respectively, take saturated potassium oxalate solution, hydrazine hydrate and saturated potassium nitrite solution in a volume ratio of 0.4:0.4:0.2 in a beaker, stir evenly, use potassium hydroxide to control the system to be alkaline during the preparation process, and prepare potassium oxalate-hydrazine hydrate-potassium nitrite reducing agent.
[0047] Dissolve 500g of chloroplatinic acid solid in 2000mL of deionized water and place it on a magnetic stirrer with heating function, heat it at 85℃ for 15min, and slowly add 20mL of potassium oxalate-hydrazine hydrate-potassium nitrite reducing agent until the solution turns reddish brown. Then slowly add a 1:1 dilute hydrochloric acid solution to the solution, and accurately control the pH value of the solution to 1, 3, and 5, respectively, until no reddish brown gas is generated. After continuing to heat for 15min, slowly add 215mL of saturated potassium chloride solution and heat for 20min, then transfer the solution to a rotary evaporator and concentrate and crystallize at 100℃ to obtain potassium chloroplatinite solid.
[0048] Table 4 Potassium chloroplatinite solid analysis test results of Comparative Example 4
[0049] Solution pH Yield purity Pt content 1 99.3％ 99.6％ 47.1％ 3 99.2％ 99.3％ 47.0％ 5 99.0％ 99.2％ 46.9％
[0050] Comparative Example 5.
[0051] An appropriate amount of potassium nitrite solid is prepared into a saturated solution. Hydrazine hydrate, hydrazine hydrochloride and saturated potassium nitrite solution are taken in a beaker in a volume ratio of 0.4:0.4:0.2 and stirred evenly. During the preparation process, potassium hydroxide is used to control the system to be alkaline to obtain hydrazine hydrate-hydrazine hydrochloride-potassium nitrite reducing agent.
[0052] Dissolve 500g of chloroplatinic acid solid in 2000mL of deionized water and place it on a magnetic stirrer with heating function, heat it at 85℃ for 15min, and slowly add 20mL of hydrazine hydrate-hydrazine hydrochloride-potassium nitrite reducing agent until the solution turns reddish brown. Then slowly add a 1:1 dilute hydrochloric acid solution to the solution, and accurately control the pH value of the solution to 1, 3, and 5, respectively, until no reddish brown gas is generated. After continuing to heat for 15min, slowly add 215mL of saturated potassium chloride solution and heat for 20min, then transfer the solution to a rotary evaporator and concentrate and crystallize at 100℃ to obtain potassium chloroplatinite solid.
[0053] Table 5 Potassium chloroplatinite solid analysis test results of comparative example 5
[0054] Solution pH Yield purity Pt content 1 99.4％ 99.7％ 47.3％ 3 99.3％ 99.4％ 47.0％ 5 99.1％ 99.2％ 46.7％
Claims
1. A method for preparing high-purity potassium chloroplatinite, characterized in that: The following steps are involved: Step 1, compounding potassium nitrite and a reducing agent to obtain a compound reducing agent; Step 2, preparing chloroplatinic (II) acid solution; Step 3, prepare potassium chloroplatinite.
2. The method for preparing high-purity potassium chloroplatinite according to claim 1, characterized in that: In the step 1, the reducing agent is hydrazine hydrochloride.
3. The method for preparing high-purity potassium chloroplatinite according to claim 1, characterized in that: In the step 1, the composite reducing agent is a hydrazine hydrochloride-potassium nitrite reducing agent; the preparation method of the hydrazine hydrochloride-potassium nitrite reducing agent is: take an appropriate amount of potassium nitrite solid to prepare a saturated solution, take the hydrazine hydrochloride and the saturated potassium nitrite solution in a beaker at a volume ratio of 0.8:0.2, stir evenly, and use potassium hydroxide to control the system to be alkaline during the preparation process.
4. The method for preparing high-purity potassium chloroplatinite according to claim 1, characterized in that: The specific steps of step 2 are as follows: 500-1000g of chloroplatinic acid solid is placed in a beaker, 2000mL-3000mL of deionized water is added, and the chloroplatinic acid solid is fully stirred to completely dissolve, and then the beaker is transferred to a magnetic stirrer with a heating function, and heated at 70-100°C and a composite reducing agent is added to the solution under magnetic stirring until the solution turns reddish brown, and then the pH of the solution is adjusted to acidic with a 1:1 dilute hydrochloric acid solution to remove the generated Pt(NO2)4 2- Conversion to PtCl4 2- , continue heating for 10-20 minutes to obtain chloroplatinic (II) acid solution.
5. The method for preparing high-purity potassium chloroplatinite according to claim 4, characterized in that: The pH value is 1.
6. The method for preparing high-purity potassium chloroplatinite according to claim 1, characterized in that: The specific steps of step 3 are: heating the chloroplatinic acid (II) solution obtained in step 2 at 70-100° C. and slowly adding a saturated potassium chloride solution with an equal molar number to the platinum in the chloroplatinic acid solution under magnetic stirring, and continuing heating for 30-50 minutes to obtain a potassium chloroplatinite solution, and transferring the obtained potassium chloroplatinite solution to a rotary evaporator for heating, concentration, drying and crystallization to obtain a reddish-brown potassium chloroplatinite solid.