Preparation method of 1, 3-propylene glycol

Abstract

The invention provides a preparation method of 1, 3-propylene glycol, which comprises the following steps: step 1, glycerol and a catalyst are added into a reactor, air in the reactor is replaced with hydrogen, the concentration of glycerol is 300-500g / L, and the molar ratio of glycerol to hydrogen is 1: 1-1: 8; 2, heating and pressurizing the interior of the reactor in the step 1, and controlling the flow rate of hydrogen to 1.0-3.0 L / min to obtain a solution A; 3, adding the solution A and silicon dioxide powder into a stirring tank, heating, stirring at a low speed, and stirring at a high speed after primary stirring is completed, so as to obtain a solution B after stirring is completed; step 4, adding the solution B and carbon nanotubes into a stirring tank, heating and stirring to obtain a solution C after stirring is completed; the 1, 3-propylene glycol is prepared by adopting a glycerol direct hydrodeoxygenation method and utilizing Pt / WOx / Beta or PtSn / PtLa as a catalyst, the yield is ideal, and the selectivity of the 1, 3-propylene glycol is high.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and more specifically, the present invention relates to a method for preparing 1,3-propanediol. Background Art

[0002] 1,3-propanediol (1,3-PDO) is the most important aliphatic diol, mainly used in the synthesis of plasticizers, detergents, preservatives, and emulsifiers, and also used in industries such as food, cosmetics, and pharmaceuticals. Its most important use is as a polymer monomer to synthesize high-performance polymer materials. It can not only endow polyester plastics with biodegradable characteristics of natural circulation, but also is an important monomer raw material for manufacturing the novel polyester fiber polytrimethylene terephthalate (PTT) with excellent performance, and can replace ethylene glycol and butanediol to produce polyol polyesters.

[0003] In the Chinese patent with the patent application number CN200810186614.8, a catalyst and process method for preparing 1,3-propanediol by one-step catalytic conversion of glycerol were proposed. A copper-based hydrogenation catalyst was used. After the glycerol raw material was vaporized, the steam was mixed and diluted with hydrogen, and continuously entered a fixed-bed reactor. The reaction was carried out under the reaction conditions of a reaction temperature of 190 - 240°C and a pressure of 0.1 - 0.54 MPa to produce 1,3-propanediol. However, the high reaction temperature caused many side reactions, and the energy consumption required for glycerol vaporization was large. The reaction space velocity of glycerol was low, and at the same time, the product selectivity was low, the yield of 1,3-propanediol was not ideal, and the selectivity of 1,3-propanediol was low.

[0004] In the Chinese patent with the patent application number CN202110820284.9, a method for preparing 1,3-propanediol was proposed. The preparation method includes: dehydrating and hydrogenating bioglycerol and hydrogen under the action of a catalyst to obtain a 1,3-propanediol system. Among them, the catalyst is a Pt / WO3ZrO2MOx catalyst, and MOx is TiO2 or a mixture of TiO2 and Al2O3. The dehydrating and hydrogenating reaction is carried out under the reaction conditions of a temperature of 120 - 180°C and a mass space velocity of bioglycerol of 0.3 - 1.5 h-1 to produce 1,3-propanediol. However, the prepared 1,3-propanediol has poor electrical conductivity and thermal stability.

[0005] Therefore, the present application provides a method for preparing 1,3-propanediol to solve the problems of the existing 1,3-propanediol preparation methods, including the unsatisfactory yield of 1,3-propanediol, low selectivity of 1,3-propanediol, and poor electrical conductivity and thermal stability of the prepared 1,3-propanediol. Summary of the Invention

[0006] The purpose and efficacy of the present invention are achieved by the following specific technical means: A method for preparing 1,3-propanediol, comprising the following steps:

[0007] Step 1: Add glycerol and catalyst into the reactor, displace the air in the reactor with hydrogen. The glycerol concentration is 300–500 g / L, and the molar ratio of glycerol to hydrogen is 1:1–1:8;

[0008] Step 2: Heat up and pressurize the reactor in Step 1, control the hydrogen flow rate to 1.0–3.0 L / min to obtain Solution A;

[0009] Step 3: Add Solution A and silica powder into the stirring tank, heat up and stir at a low speed. After the preliminary stirring is completed, stir at a high speed. After the stirring is completed, obtain Solution B;

[0010] Step 4: Add Solution B and carbon nanotubes into the stirring tank, heat up and stir to obtain Solution C after the stirring is completed;

[0011] Step 5: Add an appropriate amount of internal standard to Solution C, perform centrifugation and primary filtration, change the sieve for secondary filtration to obtain 1,3-propanediol.

[0012] Preferably, in Step 1, the catalyst is Pt / WOx / Beta or PtSn / PtLa. The selected catalyst has good catalytic effect in the reaction.

[0013] Preferably, in Step 2, the reaction temperature is 180–220 °C, the pressure in the reactor is 2–5 MPa, the reactor is a continuous trickle bed reactor, and the reaction time is 1–3 h. Using a continuous trickle bed reactor has a fast reaction rate and high purity of the prepared substance.

[0014] Preferably, in Step 3, the ratio of the silica powder to Solution A is 1%–3%:97%–99%.

[0015] Preferably, in Step 3, the preliminary heating temperature is 40–60 °C, the low-speed stirring rate is 200–300 r / min, the high-speed stirring rate is 500–800 r / min, and the stirring time is 1–3 h. The two-stage stirring can make the materials mix more fully.

[0016] Preferably, in Step 4, the carbon nanotubes are one or a mixture of single-walled carbon nanotubes, multi-walled carbon nanotubes, oligomeric-walled carbon nanotubes, and thin-walled carbon nanotubes. Among them, single-walled carbon nanotubes doped with multi-walled carbon nanotubes are preferred, which can improve conductivity and effectively control costs at the same time.

[0017] Preferably, in Step 4, the ratio of the carbon nanotubes to Solution B is 0.1%–1%:99%–99.9%.

[0018] Preferably, in Step 4, the reaction temperature is 20–50 °C, the stirring rate is 500–2000 r / min, and the stirring time is 1–5 h.

[0019] Preferably, in the fifth step, the internal standard is diethylene glycol dimethyl ether, and the centrifugation rate is 8000-12000 r / min.

[0020] Preferably, in the fifth step, the mesh number of the primary filter is 12-20 meshes, and the mesh number of the secondary filter is 100-600 meshes.

[0021] Advantages of the present invention:

[0022] (1) Using glycerol direct hydrodeoxygenation method and using Pt / WOx / Beta or PtSn / PtLa as catalysts to prepare 1,3-propanediol, the yield is ideal and the selectivity of 1,3-propanediol is high;

[0023] (2) Adding silica to physically adsorb 1,3-propanediol. Silica has a large specific surface area and good adsorption performance, and can physically adsorb to form an effective physical barrier around 1,3-propanediol, which can improve the thermal stability of 1,3-propanediol.

[0024] (3) Adding carbon nanotubes for physical mixing. Carbon nanotubes have good electrical conductivity. Adding carbon nanotubes to 1,3-propanediol can effectively improve the electrical conductivity of 1,3-propanediol, enabling 1,3-propanediol to be applied to more scenarios. Specific embodiments

[0025] As used herein, the term "comprising" and its variations are open-ended, that is, "including but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0026] It should be noted that the modification of "one" and "multiple" mentioned in this application is illustrative rather than restrictive. Those skilled in the art should understand that unless clearly stated otherwise in the context, it should be understood as "one or more". "Multiple" should be understood as two or more.

[0027] In order to be able to more clearly understand the above-mentioned objects, features and advantages of the present invention, the specific embodiments will further describe the present invention in detail. The following embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and refinements made without departing from the scope of the present invention fall within the scope of patent protection of the present invention.

[0028] Example 1

[0029] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. Solution A and silica powder were added to a stirring tank. The ratio of the silica powder to solution A was 2%:98%. The temperature was raised to 50 °C and stirred at a rate of 250 r / min for 1 h, and then stirred at a high speed of 600 r / min for 1 h to obtain solution B. Solution B and 0.1% carbon nanotubes were added to the stirring tank. The temperature was raised to 40 °C and stirred at a rate of 1000 r / min for 2.5 h. After stirring, solution C was obtained. An appropriate amount of diethylene glycol dimethyl ether was added to solution C, and centrifuged at a rate of 10000 r / min. A 15-mesh sieve was selected for primary filtration, and the 300-mesh sieve was replaced for secondary filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared and subjected to a capacity test after being stored at 60 °C for 24 h. The capacity retention rate of the lithium-ion battery was measured to be 99.3%.

[0030] Example 2

[0031] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. Solution A and silica powder were added to a stirring tank. The ratio of the silica powder to solution A was 2%:98%. The temperature was raised to 50 °C and stirred at a rate of 250 r / min for 1 h, and then stirred at a high speed of 600 r / min for 1 h to obtain solution B. Solution B and 0.1% carbon nanotubes were added to the stirring tank. The temperature was raised to 40 °C and stirred at a rate of 1000 r / min for 2.5 h. After stirring, solution C was obtained. An appropriate amount of diethylene glycol dimethyl ether was added to solution C, and centrifuged at a rate of 10000 r / min. A 15-mesh sieve was selected for primary filtration, and the 300-mesh sieve was replaced for secondary filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared and subjected to a capacity test after being stored at 60 °C for 48 h. The capacity retention rate of the lithium-ion battery was measured to be 98.7%.

[0032] Example 3

[0033] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. Solution A and silica powder were added to a stirring tank. The ratio of the silica powder to solution A was 2%:98%. The temperature was raised to 50 °C and stirring was carried out at a rate of 250 r / min for 1 h, and then high-speed stirring was carried out at a rate of 600 r / min for 1 h to obtain solution B. Solution B and 0.1% carbon nanotubes were added to the stirring tank. The temperature was raised to 40 °C and stirring was carried out at a rate of 1000 r / min for 2.5 h. After stirring was completed, solution C was obtained. An appropriate amount of diethylene glycol dimethyl ether was added to solution C, and centrifugation was carried out at a rate of 10000 r / min. A 15-mesh sieve was selected for primary filtration, and the 300-mesh sieve was replaced for secondary filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared and subjected to a capacity test after 72 h of high-temperature storage at 60 °C. The capacity retention rate of the lithium-ion battery was measured to be 98.1%.

[0034] Example 4

[0035] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. Solution A and silica powder were added to a stirring tank. The ratio of the silica powder to solution A was 2%:98%. The temperature was raised to 50 °C and stirring was carried out at a rate of 250 r / min for 1 h, and then high-speed stirring was carried out at a rate of 600 r / min for 1 h to obtain solution B. Solution B and 0.1% carbon nanotubes were added to the stirring tank. The temperature was raised to 40 °C and stirring was carried out at a rate of 1000 r / min for 2.5 h. After stirring was completed, solution C was obtained. An appropriate amount of diethylene glycol dimethyl ether was added to solution C, and centrifugation was carried out at a rate of 10000 r / min. A 15-mesh sieve was selected for primary filtration, and the 300-mesh sieve was replaced for secondary filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared and subjected to a capacity test after 144 h of high-temperature storage at 60 °C. The capacity retention rate of the lithium-ion battery was measured to be 96.2%.

[0036] Comparative Example 1

[0037] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature in the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, keep the molar ratio of glycerol to hydrogen at 1:4, set the hydrogen flow rate at 2 L / min, and react for 2 h to obtain solution A. Add an appropriate amount of diethylene glycol dimethyl ether to solution A, centrifuge at a rate of 10,000 r / min, select a 15-mesh sieve for primary filtration, and then replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte. Use this electrolyte to prepare a button cell, store it at 60 °C for 24 h, and then conduct a capacity test. The measured capacity retention rate of the lithium-ion battery is 97.9%.

[0038] Comparative Example 2

[0039] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature in the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, keep the molar ratio of glycerol to hydrogen at 1:4, set the hydrogen flow rate at 2 L / min, and react for 2 h to obtain solution A. Add an appropriate amount of diethylene glycol dimethyl ether to solution A, centrifuge at a rate of 10,000 r / min, select a 15-mesh sieve for primary filtration, and then replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte. Use this electrolyte to prepare a button cell, store it at 60 °C for 48 h, and then conduct a capacity test. The measured capacity retention rate of the lithium-ion battery is 95.3%.

[0040] Comparative Example 3

[0041] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature in the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, keep the molar ratio of glycerol to hydrogen at 1:4, set the hydrogen flow rate at 2 L / min, and react for 2 h to obtain solution A. Add an appropriate amount of diethylene glycol dimethyl ether to solution A, centrifuge at a rate of 10,000 r / min, select a 15-mesh sieve for primary filtration, and then replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte. Use this electrolyte to prepare a button cell, store it at 60 °C for 72 h, and then conduct a capacity test. The measured capacity retention rate of the lithium-ion battery is 91.6%.

[0042] Comparative Example 4

[0043] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature in the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, keep the molar ratio of glycerol to hydrogen at 1:4, set the hydrogen flow rate at 2 L / min, and react for 2 h to obtain solution A. Add an appropriate amount of diethylene glycol dimethyl ether to solution A, centrifuge at a rate of 10,000 r / min, select a 15-mesh sieve for primary filtration, and then replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte. Use this electrolyte to prepare a button cell, conduct a capacity test after high-temperature storage at 60 °C for 144 h, and measure the capacity retention rate of the lithium-ion battery to be 88.7%.

[0044] Use the 1,3-propanediol obtained in the examples and comparative examples to prepare electrolytes for lithium batteries. Prepare button cells using the same amounts of raw materials, catalysts, and additives, conduct high-temperature storage tests at the same temperature for different durations, and perform charge-discharge capacity retention rate tests on the machine. The test results are shown in Table 1

[0045] Table 1

[0046]

[0047]

[0048] After testing, adding silica for physical adsorption of 1,3-propanediol, silica has a large specific surface area and good adsorption performance, can physically adsorb to form an effective physical barrier around 1,3-propanediol, and can improve the thermal stability of 1,3-propanediol.

[0049] Example 5

[0050] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature inside the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, with the molar ratio of glycerol to hydrogen being 1:4 and the hydrogen flow rate being 2 L / min. React for 2 h to obtain solution A. Add solution A and silica powder to a stirring tank, with the ratio of silica powder to solution A being 2%:98%. Heat to 50 °C and stir at a rate of 250 r / min for 1 h, then stir at a high speed of 600 r / min for 1 h to obtain solution B. Add solution B and 0.1% carbon nanotubes to the stirring tank, heat to 40 °C and stir at a rate of 1000 r / min for 2.5 h. After stirring is completed, obtain solution C. Add an appropriate amount of diethylene glycol dimethyl ether to solution C, centrifuge at a rate of 10000 r / min, select a 15-mesh sieve for primary filtration, and replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte, use this electrolyte to prepare a button cell, and use a conductivity meter to measure the conductivity. After measurement, the conductivity is 3×10 -6 S / cm.

[0051] Example 6

[0052] Add a glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst to a continuous trickle-bed reactor. Replace the air in the reactor with hydrogen. Heat the temperature inside the continuous trickle-bed reactor to 200 °C, adjust the air pressure to 3 MPa, with the molar ratio of glycerol to hydrogen being 1:4 and the hydrogen flow rate being 2 L / min. React for 2 h to obtain solution A. Add solution A and silica powder to a stirring tank, with the ratio of silica powder to solution A being 2%:98%. Heat to 50 °C and stir at a rate of 250 r / min for 1 h, then stir at a high speed of 600 r / min for 1 h to obtain solution B. Add solution B and 0.5% carbon nanotubes to the stirring tank, heat to 40 °C and stir at a rate of 1000 r / min for 2.5 h. After stirring is completed, obtain solution C. Add an appropriate amount of diethylene glycol dimethyl ether to solution C, centrifuge at a rate of 10000 r / min, select a 15-mesh sieve for primary filtration, and replace it with a 300-mesh sieve for secondary filtration to obtain 1,3-propanediol. Use this 1,3-propanediol as a raw material to prepare a lithium-ion battery electrolyte, use this electrolyte to prepare a button cell, and use a conductivity meter to measure the conductivity. After measurement, the conductivity is 2.6×10 -6 S / cm.

[0053] Example 7

[0054] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. Solution A and silica powder were added to a stirring tank. The ratio of silica powder to solution A was 2%:98%. The temperature was raised to 50 °C and stirred at a rate of 250 r / min for 1 h, and then stirred at a high speed of 600 r / min for 1 h to obtain solution B. Solution B and 1% carbon nanotubes were added to the stirring tank. The temperature was raised to 40 °C and stirred at a rate of 1000 r / min for 2.5 h. After stirring, solution C was obtained. An appropriate amount of diethylene glycol dimethyl ether was added to solution C, and centrifuged at a rate of 10000 r / min. A 15-mesh sieve was selected for the first filtration, and the 300-mesh sieve was replaced for the second filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared, and the conductivity was tested using a conductivity meter. The measured conductivity was 2.4×10 -6 S / cm.

[0055] Comparative Example 5

[0056] A glycerol solution with a concentration of 500 g / L and a Pt / WOx / Beta composite catalyst were added to a continuous trickle-bed reactor. The air in the reactor was replaced with hydrogen. The temperature in the continuous trickle-bed reactor was raised to 200 °C, the air pressure was adjusted to 3 MPa, the molar ratio of glycerol to hydrogen was 1:4, the hydrogen flow rate was 2 L / min, and the reaction was carried out for 2 h to obtain solution A. An appropriate amount of diethylene glycol dimethyl ether was added to solution A, and centrifuged at a rate of 10000 r / min. A 15-mesh sieve was selected for the first filtration, and the 300-mesh sieve was replaced for the second filtration to obtain 1,3-propanediol. Using this 1,3-propanediol as a raw material, a lithium-ion battery electrolyte was prepared. Using this electrolyte, a button cell was prepared, and the conductivity was tested using a conductivity meter. The measured conductivity was 1.5×10 -3 S / cm.

[0057]

[0058]

[0059] After testing, adding carbon nanotubes for physical mixing, the carbon nanotubes have good electrical conductivity. Adding carbon nanotubes to 1,3-propanediol can effectively improve the electrical conductivity of 1,3-propanediol. Among them, adding 0.1% of carbon nanotubes has the best electrical conductivity. The measured conductivity is 3×10-6 S / cm.

[0060] In order to more clearly understand the above-mentioned objects, features, and advantages of the present invention, the following detailed description further elaborates on the present invention. The following embodiments are merely examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, any modifications and refinements made without departing from the scope of the present invention fall within the patent protection of the present invention.

Claims

1. A method for preparing 1,3 - propanediol, characterized in that, It includes the following steps: Step 1: Add glycerol and a catalyst into a reactor, displace the air in the reactor with hydrogen. The glycerol concentration is 300–500 g / L, and the molar ratio of glycerol to hydrogen is 1:1–1:8; Step 2: Heat up and pressurize the reactor in Step 1, control the hydrogen flow rate to 1.0–3.0 L / min to obtain Solution A; Step 3: Add Solution A and silica powder into a stirring tank, heat up and carry out low-speed stirring. After the initial stirring is completed, carry out high-speed stirring. After the stirring is completed, obtain Solution B; Step 4: Add Solution B and carbon nanotubes into a stirring tank, heat up and stir to obtain Solution C after the stirring is completed; Step 5: Add an appropriate amount of internal standard to Solution C, carry out centrifugation and primary filtration, change the sieve mesh for secondary filtration to obtain 1,3-propanediol.

2. The preparation method of 1,3-propanediol according to claim 1, characterized in that: In Step 1, the catalyst is Pt / WOx / Beta or PtSn / PtLa.

3. The preparation method of 1,3-propanediol according to claim 1, characterized in that: In Step 2, the reaction temperature is 180–220 °C, the pressure inside the reactor is 2–5 MPa, the reactor is a continuous trickle bed reactor, and the reaction time is 1–3 h.

4. The preparation method of 1,3 - propanediol according to claim 1, characterized in that: In Step 3, the ratio of the silica powder to Solution A is 1%-3%:97%-99%.

5. A method for preparing 1,3-propanediol according to claim 1, characterized in that: In Step 3, the initial heating temperature is 40–60 °C, the low-speed stirring rate is 200–300 r / min, the high-speed stirring rate is 500–800 r / min, and the stirring time is 1–3 h.

6. The preparation method of 1,3-propanediol according to claim 1, characterized in that: In Step 4, the carbon nanotubes are one or a mixture of single-walled carbon nanotubes, multi-walled carbon nanotubes, oligomeric carbon nanotubes, and thin-walled carbon nanotubes.

7. A method for preparing 1,3-propanediol according to claim 1, characterized in that: In Step 4, the ratio of the carbon nanotubes to Solution B is 0.1%-1%:99%-99.9%.

8. The preparation method of 1,3-propanediol according to claim 1, characterized in that: In Step 4, the reaction temperature is 20–50 °C, the stirring rate is 500–2000 r / min, and the stirring time is 1–5 h.

9. The preparation method of 1,3 - propanediol according to claim 1, characterized in that: In Step 5, the internal standard is diethylene glycol dimethyl ether, and the centrifugation rate is 8000–12000 r / min.

10. The method for preparing 1,3 - propanediol according to claim 1, wherein: In Step 5, the sieve mesh number for the primary filtration is 12–20 mesh, and the sieve mesh number for the secondary filtration is 100–600 mesh.

Images