A method for recycling and reusing solvents of rare earth cis-1,4-polybutadiene rubber

Abstract

The present invention belongs to the technical field of solvent recovery and reuse, and particularly relates to a method for recovering and reusing the solvent of rare earth cis-1,4-polybutadiene rubber. In the present invention, aiming at the problem that the rectification process is usually adopted for the recovery of n-hexane solvent in the prior art, but the rectification process itself has complex operation procedures and high energy consumption, a method for recovering and reusing the solvent of rare earth cis-1,4-polybutadiene rubber is provided, which includes filtering the mixed liquid after the reaction, pumping the liquid phase into a buffer tank, and naturally cooling it to room temperature; adding peracetic acid solution and sodium carbonate solution into the buffer tank and stirring to obtain a reaction liquid; adding a large amount of water to the reaction liquid to quench the reaction, separating the liquid, and drying the organic phase after several water washings to obtain the recovered n-hexane. In the recovery process of the present invention, the rectification process usually adopted in the prior art is not used, and the recovered n-hexane is applied in the polymerization process of rare earth cis-1,4-polybutadiene rubber, and it does not have an obvious impact on the polymerization process of rare earth cis-1,4-polybutadiene rubber, greatly saving the energy consumption required for recovery.

Description

Technical Field

[0001] The present invention belongs to the technical field of solvent recovery and reuse, and particularly relates to a method for recovering and reusing the solvent of rare earth cis-1,4-polybutadiene rubber. Background Art

[0002] Rare earth cis-1,4-polybutadiene rubber, also known as neodymium-based cis-1,4-polybutadiene rubber, is a kind of cis-1,4-polybutadiene rubber polymerized by a catalytic system mainly composed of rare earth metal neodymium. Using this rubber as raw material to manufacture tires can greatly improve the quality and performance of tires. In the production of rare earth cis-1,4-polybutadiene rubber, n-hexane is usually used as a solvent. In the prior art, the recovery of n-hexane solvent usually adopts the distillation process, but the distillation process itself has complex operation procedures and high energy consumption. Therefore, there is an urgent need to provide a simple, convenient and low-energy-consuming n-hexane recovery process, and the recovered n-hexane can be used in a new polymerization reaction.

[0003] For example, the Chinese invention patent application discloses a method for recovering 98% concentration n-hexane solvent oil [Application No.: 201510749504.8]. This invention application includes: Step 1, oxidizing the waste liquid of n-hexane solvent oil and separating the organic layer; Step 2, treating the separated organic layer with a catalyst under the condition of 140-170 °C; Step 3, adsorbing the liquid treated in Step 2 with activated carbon and collecting the distilled crude n-hexane solvent oil; Step 4, distilling the collected crude n-hexane solvent oil and collecting the fraction at 67-69 °C under the pressure of 5-10 mmHg.

[0004] Although this invention application realizes the recovery of 98% concentration n-hexane solvent oil, it still adopts the distillation process, so there are still the above problems of complex operation procedures and high energy consumption. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a method for recovering and reusing the solvent of rare earth cis-1,4-polybutadiene rubber that can simply and economically recover the solvent and be used in a new polymerization process.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for recovering and reusing the solvent of rare earth cis-1,4-polybutadiene rubber includes the following steps:

[0008] Step 1: Filter the reacted mixed liquid, separate the solid and liquid, and pump the liquid phase into a buffer tank and naturally cool it to room temperature;

[0009] Step 2: Under the stirring condition, add a 20% mass fraction of peracetic acid solution and a 25% mass fraction of sodium carbonate solution into the buffer tank, and stir for 2-3 h to obtain a reaction liquid;

[0010] Step 3: Add a large amount of water to the reaction solution obtained in Step 2 to quench the reaction, separate the layers, wash the organic phase several times with water and then dry it to obtain the recycled n-hexane.

[0011] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and prepare cis-1,4-polybutadiene rubber through the preparation steps of rare-earth cis-1,4-polybutadiene rubber.

[0012] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the mass of the peracetic acid solution in Step 2 is 4% of the total mass of the mixed solution in the buffer tank.

[0013] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the mass of the sodium carbonate solution in Step 2 is 10% of the total mass of the mixed solution in the buffer tank.

[0014] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the sodium carbonate solution in Step 2 is added in a stepwise manner.

[0015] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, in Step 2, 20% of the total mass of the sodium carbonate solution is added immediately after adding the peracetic acid solution. After reacting for 15 minutes, 45% of the total mass of the sodium carbonate solution is added, and after reacting for 90 minutes, 35% of the total mass of the sodium carbonate solution is added.

[0016] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the temperature during the reaction in Step 2 is 35°C.

[0017] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the drying in Step 3 is achieved by adding anhydrous sodium sulfate.

[0018] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the drying in Step 3 is achieved by sequentially transporting the organic phase into the activated alumina tank and the molecular sieve tank.

[0019] In the above method for recycling and reusing the solvent of rare-earth cis-1,4-polybutadiene rubber, the preparation steps of rare-earth cis-1,4-polybutadiene rubber in Step 4 include:

[0020] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain the first mixed solution;

[0021] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain the second mixed solution;

[0022] Step C: Then, add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out a polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transfer the mass regulator to the polymerization reactor and continue the reaction. The total reaction duration is 3 h to obtain cis-butadiene rubber.

[0023] In the above method for recycling and reusing the solvent of rare earth cis-butadiene rubber, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst, and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0024] Compared with the existing technology, the advantages of the present invention are as follows:

[0025] In the recycling process of the present invention, the rectification process commonly used in the existing technology is not adopted. The n-hexane recovered is applied in the polymerization process of rare earth cis-butadiene rubber, and it does not significantly affect the polymerization process of rare earth cis-butadiene rubber, greatly saving the energy consumption required for recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of the present invention;

[0027] In the figure: buffer tank 100, activated alumina tank 200, molecular sieve tank 300. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described in detail below with reference to the drawings in the specification and the specific embodiments.

[0029] Example 1

[0030] This example provides a method for preparing rare earth cis-butadiene rubber, including the following steps:

[0031] Step 1: Filter the reacted mixed solution to separate the solid and liquid phases, pump 100 kg of the liquid phase into the buffer tank 100, and naturally cool it to room temperature;

[0032] Step 2: At a temperature of 35 °C and under stirring conditions, add 4 kg of a 20% peracetic acid solution to the buffer tank 100, and then immediately add 2 kg of a 25% sodium carbonate solution. After reacting for 15 min, add another 4.5 kg of a 25% sodium carbonate solution. After reacting for 90 min, add another 3.5 kg of a 25% sodium carbonate solution, and stir for a total of 2.5 h to obtain a reaction solution;

[0033] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, perform liquid separation, wash the organic phase several times with water and then dry it to obtain the recycled n-hexane. Among them, the drying is achieved by sequentially transporting the organic phase into the activated alumina tank 200 and the molecular sieve tank 300;

[0034] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and obtain cis-butadiene rubber through the preparation steps of rare earth cis-butadiene rubber.

[0035] The preparation steps of the rare earth cis-butadiene rubber in Step 4 include:

[0036] Step A: Transport the n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0037] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0038] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-butadiene rubber.

[0039] Among them, the mass ratio of the butadiene monomer to the n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0040] Example 2

[0041] This example provides a preparation method of rare earth cis-butadiene rubber, including the following steps:

[0042] Step 1: Filter the reacted mixed solution, perform solid-liquid separation, pump 100 kg of the liquid phase into the buffer tank 100, and naturally cool it to room temperature;

[0043] Step 2: Under the conditions of a temperature of 35 °C and stirring, add 10 kg of a peracetic acid solution with a mass fraction of 20% to the buffer tank 100, and then immediately add 1 kg of a sodium carbonate solution with a mass fraction of 25%. After reacting for 15 min, add 2.25 kg of a sodium carbonate solution with a mass fraction of 25% again. After reacting for 90 min, add 1.75 kg of a sodium carbonate solution with a mass fraction of 25%. Stir for a total of 2 h to obtain a reaction solution;

[0044] Step 3: Add 200 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the layers, wash the organic phase with water several times and then dry it to obtain the recycled n-hexane. The drying is achieved by sequentially transporting the organic phase into the activated alumina tank 200 and the molecular sieve tank 300;

[0045] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and prepare cis-butadiene rubber through the preparation steps of rare earth cis-butadiene rubber.

[0046] The preparation steps of the rare earth cis-butadiene rubber in Step 4 include:

[0047] Step A: Transport the n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0048] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0049] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-butadiene rubber.

[0050] Among them, the mass ratio of the butadiene monomer to the n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0051] Example 3

[0052] This example provides a preparation method of rare earth cis-butadiene rubber, including the following steps:

[0053] Step 1: Filter the reacted mixed solution, separate the solid and liquid, pump 100 kg of the liquid phase into the buffer tank 100, and naturally cool it to room temperature;

[0054] Step 2: At a temperature of 35 °C and under stirring conditions, add 2 kg of a 20% peracetic acid solution to the buffer tank 100, and then immediately add 4 kg of a 25% sodium carbonate solution. After reacting for 15 min, add 9 kg of a 25% sodium carbonate solution, react for 90 min, and then add 7 kg of a 25% sodium carbonate solution. Stir for a total of 3 h to obtain a reaction solution;

[0055] Step 3: Add 500 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the layers, wash the organic phase with water several times and then dry it to obtain the recycled n-hexane, wherein the drying is achieved by adding anhydrous sodium sulfate;

[0056] Step 4: Mix the recycled n-hexane prepared in Step 3 with butadiene monomer, and prepare cis-butadiene rubber through the preparation steps of rare earth cis-butadiene rubber.

[0057] The preparation steps of the rare earth cis-butadiene rubber in Step 4 include:

[0058] Step A: Transport n-hexane and butadiene monomer to a polymerization reactor and mix them to obtain a first mixed solution;

[0059] Step B: Transport the first catalyst to the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0060] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out a polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator to the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-butadiene rubber.

[0061] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0062] Example 4

[0063] This example provides a method for preparing rare earth cis-butadiene rubber, including the following steps:

[0064] Step 1: Filter the reacted mixed solution, separate the solid and liquid, pump 100 kg of the liquid phase into buffer tank 100, and naturally cool it to room temperature;

[0065] Step 2: Add 4 kg of peracetic acid solution with a mass fraction of 20% to buffer tank 100 under the conditions of a temperature of 35 °C and stirring, and then immediately add 10 kg of sodium carbonate solution with a mass fraction of 25%. Stir for a total of 2.5 h to obtain a reaction solution;

[0066] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, perform liquid separation, wash the organic phase several times with water and then dry it to obtain the recycled n-hexane. The drying is achieved by sequentially transporting the organic phase into the activated alumina tank 200 and the molecular sieve tank 300;

[0067] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and obtain cis-butadiene rubber through the preparation steps of rare earth cis-butadiene rubber.

[0068] The preparation steps of the rare earth cis-butadiene rubber in Step 4 include:

[0069] Step A: Transport the n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0070] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0071] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-butadiene rubber.

[0072] Among them, the mass ratio of the butadiene monomer to the n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0073] Example 5

[0074] This example provides a preparation method of rare earth cis-butadiene rubber, including the following steps:

[0075] Step 1: Filter the reacted mixed solution, perform solid-liquid separation, pump 100 kg of the liquid phase into the buffer tank 100, and naturally cool it to room temperature;

[0076] Step 2: Under the conditions of a temperature of 35 °C and stirring, add 4 kg of a peracetic acid solution with a mass fraction of 20% to the buffer tank 100, and then immediately add 3.3 kg of a sodium carbonate solution with a mass fraction of 25%. After reacting for 60 min, add 3.3 kg of a sodium carbonate solution with a mass fraction of 25% again. After reacting for 120 min, add 3.4 kg of a sodium carbonate solution with a mass fraction of 25%. Stir for a total of 2.5 h to obtain a reaction solution;

[0077] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the layers, wash the organic phase with water several times and then dry it to obtain the recycled n-hexane. The drying is achieved by sequentially transporting the organic phase into the activated alumina tank 200 and the molecular sieve tank 300;

[0078] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and prepare cis-1,4-polybutadiene rubber through the preparation steps of rare earth cis-1,4-polybutadiene rubber.

[0079] The preparation steps of rare earth cis-1,4-polybutadiene rubber in Step 4 include:

[0080] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0081] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0082] Step C: Then add the second catalyst and the third catalyst into the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0083] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0084] Example 6

[0085] This example provides a preparation method of rare earth cis-1,4-polybutadiene rubber, including the following steps:

[0086] Step 1: Filter the reacted mixed solution, separate the solid and liquid, pump 100 kg of the liquid phase into the buffer tank 100, and naturally cool it to room temperature;

[0087] Step 2: Add 4 kg of peracetic acid solution with a mass fraction of 20% to the buffer tank 100 at a temperature of 35 °C under stirring conditions, react for 120 min, then add 10 kg of sodium carbonate solution with a mass fraction of 25%, and stir for a total of 2.5 h to obtain a reaction solution;

[0088] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the layers, wash the organic phase several times with water and then dry it to obtain the recycled n-hexane. The drying is achieved by sequentially transporting the organic phase into the activated alumina tank 200 and the molecular sieve tank 300;

[0089] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and prepare cis-1,4-polybutadiene rubber through the preparation steps of rare-earth cis-1,4-polybutadiene rubber.

[0090] The preparation steps of rare-earth cis-1,4-polybutadiene rubber in Step 4 include:

[0091] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0092] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0093] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0094] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0095] Comparative Example 1

[0096] This comparative example provides a preparation method of rare-earth cis-1,4-polybutadiene rubber, including the following steps:

[0097] Step 1: Filter the reacted mixed solution, separate the solid and liquid phases, and sequentially dry the liquid phase through the activated alumina tank 200 and the molecular sieve tank 300 to obtain the recycled n-hexane;

[0098] Step 2: Mix the recycled n-hexane prepared in Step 1 with the butadiene monomer, and prepare cis-1,4-polybutadiene rubber through the preparation steps of rare-earth cis-1,4-polybutadiene rubber.

[0099] The preparation steps of rare-earth cis-1,4-polybutadiene rubber in Step 2 include:

[0100] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0101] Step B: Deliver the first catalyst to the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0102] Step C: Then add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out a polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, deliver the mass regulator to the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0103] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst, and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0104] Comparative Example 2

[0105] This comparative example provides a method for preparing rare earth cis-1,4-polybutadiene rubber, including the following steps:

[0106] Step 1: Filter the reacted mixed solution, separate the solid and liquid, pump 100 kg of the liquid phase into buffer tank 100, and naturally cool it to room temperature;

[0107] Step 2: At a temperature of 15 °C and under stirring conditions, add 4 kg of a 20% peracetic acid solution to buffer tank 100, and then immediately add 2 kg of a 25% sodium carbonate solution. After reacting for 15 min, add another 4.5 kg of a 25% sodium carbonate solution. After reacting for 90 min, add another 3.5 kg of a 25% sodium carbonate solution, and stir for a total of 2.5 h to obtain a reaction solution;

[0108] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the liquid, wash the organic phase several times with water and then dry it to obtain the recycled n-hexane. Among them, the drying is achieved by sequentially delivering the organic phase to activated alumina tank 200 and molecular sieve tank 300;

[0109] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and obtain cis-1,4-polybutadiene rubber through the preparation steps of rare earth cis-1,4-polybutadiene rubber.

[0110] The preparation steps of rare earth cis-1,4-polybutadiene rubber in Step 4 include:

[0111] Step A: Deliver n-hexane and the butadiene monomer to the polymerization reactor and mix them to obtain a first mixed solution;

[0112] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0113] Step C: Then add the second catalyst and the third catalyst into the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0114] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0115] Comparative Example 3

[0116] This comparative example provides a method for preparing rare earth cis-1,4-polybutadiene rubber, including the following steps:

[0117] Step 1: Filter the reacted mixed solution to separate the solid and liquid phases, pump 100 kg of the liquid phase into buffer tank 100, and naturally cool it to room temperature;

[0118] Step 2: At a temperature of 55 °C and under stirring conditions, add 4 kg of a 20% peracetic acid solution to buffer tank 100, and then immediately add 2 kg of a 25% sodium carbonate solution. After reacting for 15 min, add another 4.5 kg of a 25% sodium carbonate solution. After reacting for 90 min, add another 3.5 kg of a 25% sodium carbonate solution, and stir for a total of 2.5 h to obtain a reaction solution;

[0119] Step 3: Add 300 kg of water to the reaction solution obtained in Step 2 to quench the reaction, separate the liquid, and the organic phase is washed several times with water and then dried to obtain the recycled n-hexane. Among them, the drying is achieved by successively transporting the organic phase into activated alumina tank 200 and molecular sieve tank 300;

[0120] Step 4: Mix the recycled n-hexane prepared in Step 3 with the butadiene monomer, and obtain cis-1,4-polybutadiene rubber through the preparation steps of rare earth cis-1,4-polybutadiene rubber.

[0121] The preparation steps of rare earth cis-1,4-polybutadiene rubber in Step 4 include:

[0122] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0123] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0124] Step C: Then add the second catalyst and the third catalyst into the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0125] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst, and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; the mass regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0126] Comparative Example 4

[0127] This comparative example provides a method for preparing rare earth cis-1,4-polybutadiene rubber, including the following steps:

[0128] Step 1: Purchase commercially available analytical pure n-hexane;

[0129] Step 2: Mix the purchased n-hexane with the butadiene monomer, and obtain cis-1,4-polybutadiene rubber through the preparation steps of rare earth cis-1,4-polybutadiene rubber.

[0130] The preparation steps of rare earth cis-1,4-polybutadiene rubber in Step 2 include:

[0131] Step A: Transport n-hexane and the butadiene monomer into the polymerization reactor and mix them to obtain a first mixed solution;

[0132] Step B: Transport the first catalyst into the polymerization reactor and mix it with the first mixed solution to obtain a second mixed solution;

[0133] Step C: Then add the second catalyst and the third catalyst into the second mixed solution, start stirring, and carry out the polymerization reaction at 50 °C. At the 15th minute after the start of the polymerization reaction, transport the mass regulator into the polymerization reactor and continue the reaction. The total reaction time is 3 h to obtain cis-1,4-polybutadiene rubber.

[0134] Among them, the mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium naphthenate; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst, and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×103 ; The quality regulator is triethylaluminum, and the addition amount is 0.15% of the mass of the butadiene monomer.

[0135] Application Example 1

[0136] The cis-1,4-polybutadiene rubber 1 was prepared by the method described in Example 1;

[0137] The cis-1,4-polybutadiene rubber 2 was prepared by the method described in Example 4;

[0138] The cis-1,4-polybutadiene rubber 3 was prepared by the method described in Example 5;

[0139] The cis-1,4-polybutadiene rubber 4 was prepared by the method described in Example 6;

[0140] The cis-1,4-polybutadiene rubber 5 was prepared by the method described in Comparative Example 1;

[0141] The cis-1,4-polybutadiene rubber 6 was prepared by the method described in Comparative Example 2;

[0142] The cis-1,4-polybutadiene rubber 7 was prepared by the method described in Comparative Example 3;

[0143] The cis-1,4-polybutadiene rubber 8 was prepared by the method described in Comparative Example 4;

[0144] The relevant determinations of the cis-1,4-polybutadiene rubbers 1-8 were carried out by the test method described in the invention patent application with the application number "202310890382.9", that is

[0145] 1. Measure the conversion rate of the butadiene monomer by the weighing method: After the reaction is completed, first add anhydrous ethanol into the reaction kettle, then open the kettle cover, and manually take out all the white solid polybutadiene in the kettle, dry it and weigh it, and calculate its conversion rate.

[0146] Conversion rate = M1 / (M2)×100%;

[0147] M1 represents the mass of the harvested cis-1,4-polybutadiene rubber; M2 represents the mass of the input butadiene monomer.

[0148] 2. Test the Mooney viscosity ML(1+4)100℃ of the raw rubber according to the standard GB / T1232.1-2016.

[0149] 3. Mix and prepare the raw rubber of the rare earth cis-1,4-polybutadiene rubber by mixing according to the C2 method in GB / T8660-2018, and then test the Mooney viscosity ML(1+4)100℃ of the mixed rubber by the Mooney machine according to the standard GB / T1232.1-2016;

[0150] The results are shown in the following table:

[0151]

[0152]

[0153] Result analysis: By comparing the test results of cis-1,4-polybutadiene rubber 1 and cis-1,4-polybutadiene rubber 8, it can be seen that there are no obvious differences in the conversion rate and performance between the products synthesized from the n-hexane recovered by the present invention and the n-hexane synthesized from commercially available analytical pure n-hexane for the synthesis of rare-earth cis-1,4-polybutadiene rubber. Therefore, the invention purpose that the present invention does not adopt the rectification process usually used in the prior art during the recovery process, and the n-hexane recovered is applied to the polymerization process of rare-earth cis-1,4-polybutadiene rubber without significantly affecting the polymerization process of rare-earth cis-1,4-polybutadiene rubber is achieved.

[0154] By comparing the test results of cis-1,4-polybutadiene rubbers 1-4, it can be seen that the addition timing of sodium carbonate during the recovery process affects the finally recovered n-hexane and the conversion rate of preparing rare-earth cis-1,4-polybutadiene rubber using this n-hexane. This may be because during the polymerization reaction process, some by-products remain in the n-hexane solvent. During the oxidation treatment with peracetic acid, since some epoxidation products are prone to ring-opening reactions under strong acid conditions, from this point of view, it is relatively beneficial for the reaction system to be kept neutral or weakly alkaline. However, the peroxy bond that plays an oxidizing role has higher activity in an acidic medium. Therefore, during the whole reaction process, the most suitable pH value for the reaction to proceed is in a process that changes with the reaction process. Therefore, the applicant has explored and found that the addition method adopted in Example 1 is superior to the addition methods of adding all the alkali liquor first, adding it step by step evenly, or adding it all at the end conventionally.

[0155] By comparing the test results of cis-1,4-polybutadiene rubbers 1, 5-7, it can be seen that the recovery method adopted by the present invention is superior to the recovery method of only drying. At the same time, it has selectivity for the reaction temperature of the recovery reaction. This may be because too low a temperature leads to too slow a reaction rate and incomplete reaction, and too high a temperature leads to accelerated decomposition of peracetic acid and a decrease in the effective concentration of peracetic acid.

[0156] The specific embodiments described herein are only illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0157] Although terms such as buffer tank 100, activated alumina tank 200, and molecular sieve tank 300 are used more frequently herein, the possibility of using other terms is not excluded. The use of these terms is only for more conveniently describing and explaining the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A method for recovering and reusing rare earth butadiene rubber solvent, characterized in that: The following steps are involved: Step 1: filtering the mixed liquid after the reaction, separating the solid and the liquid, pumping the liquid phase into a buffer tank (100), and cooling naturally to room temperature; Step 2: under stirring conditions, add a 20% by mass peracetic acid solution and a 25% by mass sodium carbonate solution into the buffer tank (100), and stir for 2-3 hours to obtain a reaction solution; Step 3: adding a large amount of water to the reaction solution obtained in step 2 to quench the reaction, separating the liquids, washing the organic phase with water several times and then drying to obtain recovered n-hexane; Step 4: mixing the recovered n-hexane obtained in step 3 with butadiene monomer to obtain butadiene rubber through a rare earth butadiene rubber preparation step; The sodium carbonate solution is added in steps in step 2; In the step 2, immediately after adding the peracetic acid solution, 20% of the total mass of the sodium carbonate solution is added, and after reacting for 15 minutes, 45% of the total mass of the sodium carbonate solution is added, and after reacting for 90 minutes, 35% of the total mass of the sodium carbonate solution is added; The temperature during the reaction of step 2 is 35°C.

2. A method for recovering and reusing a rare earth butadiene rubber solvent as claimed in claim 1, characterized in that: The mass of the peracetic acid solution in step 2 is 4% of the total mass of the mixed liquid in the buffer tank (100).

3. A method for recovering and reusing a rare earth butadiene rubber solvent as claimed in claim 1, characterized in that: The mass of the sodium carbonate solution in step 2 is 10% of the total mass of the mixed solution in the buffer tank (100).

4. A method for recovering and reusing a rare earth butadiene rubber solvent as claimed in claim 1, characterized in that: The drying in step 3 is achieved by adding anhydrous sodium sulfate.

5. A method for recovering and reusing a rare earth butadiene rubber solvent as claimed in claim 1, characterized in that: The drying in step three is achieved by sequentially conveying the organic phase to the activated alumina tank (200) and the molecular sieve tank (300).

6. A method for recovering and reusing rare earth butadiene rubber solvent as claimed in claim 1, characterized in that: The step of preparing rare earth butadiene rubber in step 4 comprises: Step A: transporting n-hexane and butadiene monomer into a polymerization reactor and mixing them to obtain a first mixed solution; Step B: transporting the first catalyst to a polymerization reactor to mix with the first mixed solution to obtain a second mixed solution; Step C: Add the second catalyst and the third catalyst to the second mixed solution, start stirring, and carry out polymerization reaction at 50°C. 15 minutes after the start of the polymerization reaction, deliver the quality regulator to the polymerization reactor and continue the reaction. The total reaction time is 3 hours to obtain butadiene rubber.

7. A method for recovering and reusing a rare earth butadiene rubber solvent as claimed in claim 6, characterized in that: The mass ratio of the butadiene monomer to n-hexane is 1:3; the first catalyst is diethylaluminum hydride; the second catalyst is neodymium cyclohexane; the third catalyst is sesquiethylaluminum chloride; the molar ratio of the first catalyst, the second catalyst and the third catalyst is 15:1:3, and the molar ratio of the second catalyst to the butadiene monomer is 1:1×10 3 ; The mass regulator is triethylaluminum, and the added amount is 0.15% of the mass of butadiene monomer.

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