A continuous production system for sodium tert-butoxide

Abstract

The present invention relates to the technical field of fine chemicals, and in particular to a continuous production system of sodium tert-butoxide, comprising the following steps: S1, pumping tert-butanol and sodium hydroxide from a raw material storage tank into a mixing kettle, stirring, preheating and mixing to obtain a preheated mixture; S2, loading a supported metal-based catalyst into a catalyst bed in a continuous reactor, pumping the preheated mixture into the continuous reactor, stirring and heat-insulating the reaction to obtain a crude product; S3, the crude product is continuously discharged through an outlet at the bottom of the continuous reactor, and after distillation and purification in a distillation tower, a finished product is obtained. The present invention realizes the continuous production of sodium tert-butoxide by optimizing the reaction conditions and the catalyst preparation process, improves the production efficiency and product purity, makes the reaction more complete, and has higher yield and purity.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a continuous production system of sodium tert-butoxide. Background Art

[0002] The chemical formula of sodium tert-butoxide is C4H9NaO, and the CAS number is 865-48-5. It is an important alkali metal alkoxide, which is widely used in fine chemicals, medicine, pesticides and organic synthesis. The alkalinity of sodium tert-butoxide is significantly stronger than that of traditional inorganic strong bases such as sodium hydroxide and potassium hydroxide, and it shows unique advantages in many chiral synthesis reactions. Sodium tert-butoxide is stable at room temperature and pressure. It is a white or off-white crystal with a melting point of about 180°C and a density of about 1.104 g / cm 3 The flash point is as low as 12°C. It is slightly reactive to water and needs to avoid contact with strong reducing agents, moisture, air and acid. At present, sodium tert-butoxide is mainly prepared by the following reactions: reaction of metallic sodium with tert-butanol, reaction of sodium hydroxide with tert-butanol, reaction of tert-butanol with alkali metal amide, reaction of sodium tert-butyl carbonate with barium hydroxide, etc. Among them, the alkaline preparation of the reaction of sodium hydroxide with tert-butanol has the advantages of safe and simple process flow and low raw material price.

[0003] In the prior art, the patent publication number is the invention patent of CN117550955A, which discloses a preparation method of sodium tert-butoxide, including adding tert-butanol and sodium hydroxide into a container in sequence, heating to reflux while stirring, reacting for a certain period of time, obtaining a crude product of sodium tert-butoxide after distilling the mixed liquid of tert-butanol and sodium hydroxide, and placing a water-absorbing bag with a water-absorbing agent in the mixed liquid of tert-butanol and sodium hydroxide, and obtaining sodium tert-butoxide after purification. But the reaction of sodium hydroxide and the tert-butanol is a balanced reversible reaction, and its equilibrium constant is relatively low, which belongs to the preparation of strong base with weak base. Therefore, a part of tert-butanol and sodium hydroxide can not be completely converted into sodium tert-butoxide, resulting in a reduction in the yield of the product, requiring a large amount of time to react. Meanwhile, incomplete reaction can increase the difficulty and cost of subsequent separation and purification. Summary of the invention

[0004] In order to solve the problems mentioned in the above background technology, the present invention provides a continuous production system of sodium tert-butoxide.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A continuous production system for sodium tert-butoxide comprises the following steps:

[0007] S1. Pump tert-butyl alcohol and sodium hydroxide from a raw material storage tank into a mixing kettle, stir and mix them evenly, and preheat them with an electric heating jacket or a steam heating coil to obtain a preheated mixture;

[0008] S2, loading the supported metal-based catalyst into the catalyst bed in the continuous reactor, pumping the preheated mixed material into the continuous reactor, stirring and heat-insulating the reaction to obtain a crude product, and providing a condensation reflux device on the top of the continuous reactor to recover the steam generated during the reaction, the steam mainly containing unreacted tert-butyl alcohol and a small amount of water, which is recovered after condensation;

[0009] S3. The crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after being purified by distillation in a distillation tower, it is discharged from the top of the distillation tower to obtain a pure sodium tert-butoxide product.

[0010] The reaction equation is:

[0011] C4H9OH+NaOH=C4H9ONa+H2O

[0012] Furthermore, in step S1, the stirring speed is 100-200 rpm, the preheating temperature is 70-75° C., and the mixing time is 5-15 min.

[0013] Furthermore, the supported metal-based catalyst in step S2 is prepared by the following steps:

[0014] A1. Mix boron nitride powder and metal oxide powder, add them into water containing 0.5-0.8wt% sodium dodecyl sulfate to form a suspension, adjust the pH value to 7-8, stir and heat to react, filter and wash, and dry to constant weight to obtain a modified metal oxide;

[0015] A2. Add the modified metal oxide to a 20-30wt% sodium diethylenetriamine penta (methylenephosphonate) solution, add polyvinyl pyrrolidone, stir to react, filter, and perform heat treatment to obtain a supported metal-based catalyst.

[0016] Furthermore, the feed mass ratio of tert-butyl alcohol, sodium hydroxide and supported metal-based catalyst is (5-7): (2-2.5): (0.08-0.18).

[0017] Furthermore, in step S2, the stirring speed is 300-400 rpm, the reaction temperature is 85-120° C., and the reaction time is 10-15 h.

[0018] Furthermore, in step A1, the mass ratio of boron nitride powder, metal oxide powder and water is (1-2): (5-7): (10-15), and the metal oxide includes one of iron oxide, cobalt oxide, nickel oxide, zinc oxide or magnesium oxide.

[0019] Furthermore, in step A1, the stirring speed is 200-300 rpm, the reaction temperature is 70-80° C., and the reaction time is 2-4 h.

[0020] Furthermore, in step A2, the mass ratio of the modified metal oxide, sodium diethylenetriamine penta (methylenephosphonate) solution and polyvinyl pyrrolidone is (2-4): (8-10): (0.15-0.35).

[0021] Furthermore, in step A2, the stirring speed is 300-400 rpm, the reaction time is 1-2 h at room temperature, the heat treatment temperature is 80-100° C., and the heat treatment time is 6-8 h.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. In this technical solution, by mixing metal oxide powder with boron nitride powder, boron nitride is used as a carrier to provide a stable support platform for the active components of the metal oxide, forming a stable and high specific surface area structure. The surface of the modified metal oxide is further treated with sodium diethylenetriamine penta (methylene phosphonate) (DTPMP) and polyvinyl pyrrolidone (PVP) to form an organic-inorganic composite layer. The multi-dentate ligand structure of DTPMP can form a strong coordination bond with the metal ions on the surface of the metal oxide, and the long chain structure of PVP forms a protective film on the surface, which helps to adjust the hydrophobicity of the catalyst. The supported metal-based catalyst reduces the activation energy of the reaction of tert-butyl alcohol and sodium hydroxide by providing abundant active sites, ensuring that the reactant molecules can more easily approach and adsorb on the catalyst surface, thereby accelerating the reaction rate.

[0024] 2. In the production process of preparing sodium tert-butoxide by alkali method, the reverse reaction will seriously affect the yield and efficiency of the product. The supported metal-based catalyst used in the technical solution of the present invention can inhibit the occurrence of the reverse reaction. Specifically, the active sites on the catalyst surface can preferentially adsorb and activate the reactant molecules, promote the forward reaction, and the hydrophobicity can inhibit the contact of water with the reactant, making it easier to evaporate, thereby reducing the speed of the reverse reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are 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.

[0028] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0029] Preparation Example 1

[0030] The supported metal-based catalyst is prepared by the following steps:

[0031] A1. Mix 1 kg of boron nitride powder and 5 kg of iron oxide powder, add 10 kg of water containing 0.5 wt% of sodium dodecyl sulfate to form a suspension, adjust the pH value to 7, heat to 70°C, stir at 200 rpm for 2 hours, filter and wash, and dry at 60°C to constant weight to obtain a modified metal oxide;

[0032] A2. Add 2 kg of modified metal oxide to 8 kg of 20 wt% sodium diethylenetriamine penta (methylene phosphonate) solution, add 0.15 kg of polyvinyl pyrrolidone, stir at 300 rpm for 1 h at room temperature, filter, and heat treat at 80 ° C for 6 h to obtain a supported metal-based catalyst.

[0033] Preparation Example 2

[0034] The supported metal-based catalyst is prepared by the following steps:

[0035] A1. Mix 1.5 kg of boron nitride powder and 6 kg of nickel oxide powder, add 12.5 kg of water containing 0.7 wt % of sodium dodecyl sulfate to form a suspension, adjust the pH value to 7, heat to 75 ° C, stir at 250 rpm for 3 hours, filter and wash, and dry at 60 ° C to constant weight to obtain a modified metal oxide;

[0036] A2. Add 3 kg of modified metal oxide to 9 kg of 25 wt% sodium diethylenetriamine penta (methylene phosphonate) solution, add 0.2 kg of polyvinyl pyrrolidone, stir at room temperature at a speed of 350 rpm for 1.5 h, filter, and heat-treat at 90 ° C for 7 h to obtain a supported metal-based catalyst.

[0037] Preparation Example 3

[0038] The supported metal-based catalyst is prepared by the following steps:

[0039] A1. Mix 2 kg of boron nitride powder and 7 kg of cobalt oxide powder, add 15 kg of water containing 0.8 wt % of sodium dodecyl sulfate to form a suspension, adjust the pH value to 8, heat to 80 ° C, stir at 300 rpm for 4 hours, filter and wash, and dry at 60 ° C to constant weight to obtain a modified metal oxide;

[0040] A2. Add 4 kg of modified metal oxide to 10 kg of 30 wt% sodium diethylenetriamine penta (methylene phosphonate) solution, add 0.35 kg of polyvinyl pyrrolidone, stir at room temperature at 400 rpm for 2 h, filter, and heat treat at 100 ° C for 8 h to obtain a supported metal-based catalyst. Example 1

[0041] A continuous production system for sodium tert-butoxide comprises the following steps:

[0042] S1. Pump 50 kg of tert-butyl alcohol and 20 kg of sodium hydroxide from the raw material storage tank into a mixing kettle, stir and mix at a speed of 100 rpm for 5 min, and preheat to 70° C. with an electric heating jacket to obtain a preheated mixture;

[0043] S2, 0.8 kg of the supported metal-based catalyst prepared in Preparation Example 1 was loaded into the catalyst bed in the continuous reactor, the preheated mixture was pumped into the continuous reactor, stirred at a speed of 300 rpm, and kept warm at 85° C. for 10 hours to obtain a crude product, and a condensing reflux device was provided on the top of the continuous reactor to recover the steam generated during the reaction, the steam mainly containing unreacted tert-butyl alcohol and a small amount of water, which was recovered after condensation;

[0044] S3. The crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after being purified by distillation in a distillation tower, it is discharged from the top of the distillation tower to obtain a pure sodium tert-butoxide product. Example 2

[0045] A continuous production system for sodium tert-butoxide comprises the following steps:

[0046] S1. Pump 55 kg of tert-butyl alcohol and 22 kg of sodium hydroxide from the raw material storage tank into a mixing kettle, stir and mix at a speed of 150 rpm for 10 min, and preheat to 73° C. with an electric heating jacket to obtain a preheated mixture;

[0047] S2, 1 kg of the supported metal-based catalyst prepared in Preparation Example 2 was loaded into the catalyst bed in the continuous reactor, the preheated mixture was pumped into the continuous reactor, stirred at a speed of 350 rpm, and kept warm at 90° C. for 12 h to obtain a crude product, and a condensing reflux device was provided on the top of the continuous reactor to recover the steam generated during the reaction, the steam mainly containing unreacted tert-butyl alcohol and a small amount of water, which was recovered after condensation;

[0048] S3. The crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after being purified by distillation in a distillation tower, it is discharged from the top of the distillation tower to obtain a pure sodium tert-butoxide product. Example 3

[0049] A continuous production system for sodium tert-butoxide comprises the following steps:

[0050] S1. Pump 60 kg of tert-butyl alcohol and 23 kg of sodium hydroxide from the raw material storage tank into a mixing kettle, stir and mix at a speed of 150 rpm for 10 min, and preheat to 73 ° C with an electric heating jacket to obtain a preheated mixture;

[0051] S2, 1.4 kg of the supported metal-based catalyst prepared in Preparation Example 3 was loaded into the catalyst bed in the continuous reactor, the preheated mixture was pumped into the continuous reactor, stirred at a speed of 350 rpm, and kept warm at 110° C. for 12 h to obtain a crude product, and a condensing reflux device was provided on the top of the continuous reactor to recover the steam generated during the reaction, the steam mainly containing unreacted tert-butyl alcohol and a small amount of water, which was recovered after condensation;

[0052] S3. The crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after being purified by distillation in a distillation tower, it is discharged from the top of the distillation tower to obtain a pure sodium tert-butoxide product. Example 4

[0053] A continuous production system for sodium tert-butoxide comprises the following steps:

[0054] S1. Pump 70 kg of tert-butyl alcohol and 25 kg of sodium hydroxide from the raw material storage tank into a mixing kettle, stir and mix at a speed of 200 rpm for 15 min, and preheat to 75° C. with an electric heating jacket to obtain a preheated mixture;

[0055] S2, 1.8 kg of the supported metal-based catalyst prepared in Preparation Example 1 was loaded into the catalyst bed in the continuous reactor, the preheated mixture was pumped into the continuous reactor, stirred at a speed of 400 rpm, and kept warm for reaction at 120° C. for 15 hours to obtain a crude product, and a condensation reflux device was provided on the top of the continuous reactor to recover the steam generated during the reaction, the steam mainly containing unreacted tert-butyl alcohol and a small amount of water, which was recovered after condensation;

[0056] S3. The crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after being purified by distillation in a distillation tower, it is discharged from the top of the distillation tower to obtain a pure sodium tert-butoxide product.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that iron oxide powder is used instead of the supported metal-based catalyst, and the remaining steps are the same as those of Example 1.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 2 is that boron nitride powder is used instead of the supported metal-based catalyst, and the remaining steps are the same as those in Example 2.

[0061] Comparative Example 3

[0062] The difference between this comparative example and Example 3 is that sodium diethylenetriamine penta(methylenephosphonate) is used instead of the supported metal-based catalyst, and the remaining steps are the same as those in Example 3.

[0063] Comparative Example 4

[0064] The difference between this comparative example and Example 4 is that polyvinyl pyrrolidone is used instead of the supported metal-based catalyst, and the remaining steps are the same as those of Example 4.

[0065] The yield, purity and reaction rate of Examples 1-4 and Comparative Examples 1-4 are shown in Table 1:

[0066] Table 1. Yield, purity and reaction rate of Examples 1-4 and Comparative Examples 1-4

[0067] serial number Yield (%) purity(%) Reaction rate (mol / h·L) Example 1 95.65 99.32 0.62 Example 2 96.24 99.54 0.64 Example 3 96.37 99.52 0.65 Example 4 96.86 99.45 0.65 Comparative Example 1 74.84 94.06 0.34 Comparative Example 2 68.93 92.32 0.31 Comparative Example 3 70.55 93.52 0.32 Comparative Example 4 67.24 90.54 0.28

[0068] According to HG / T 4879-2016 "Sodium tert-butoxide for industrial use", the total alkali content (in terms of C4H9ONa) and free alkali (in terms of sodium hydroxide) of Examples 1-4 and Comparative Examples 1-4 are shown in Table 2:

[0069] Table 2. Technical requirements of Examples 1-4 and Comparative Examples 1-4

[0070] serial number Total alkali content, w / % Free base, w / % Example 1 99.83 0.12 Example 2 99.87 0.12 Example 3 99.86 0.13 Example 4 99.89 0.11 Comparative Example 1 98.35 1.86 Comparative Example 2 96.32 3.27 Comparative Example 3 97.24 2.54 Comparative Example 4 95.54 3.41

[0071] As shown in Table 1, Examples 1-4 used supported metal-based catalysts, and the yields were all above 95.65%, showing a higher catalytic efficiency. Comparative Examples 1-4 used iron oxide powder, boron nitride powder, sodium diethylenetriamine pentamethylphosphonate, and polyvinylpyrrolidone as catalysts or substitutes, respectively, and the yields were significantly lower than those of the embodiments, indicating that supported metal-based catalysts have better catalytic performance. The purities of Examples 1-4 were all above 99.32%, indicating that supported metal-based catalysts are helpful in generating high-purity sodium tert-butoxide. The reaction rates of Examples 1-4 were all above 0.62 mol / h·L, which were better than Comparative Examples 1-4, indicating that supported metal-based catalysts can effectively accelerate the reaction rate.

[0072] It can be seen from Table 2 that the total alkali content of Examples 1-4 is all above 99.83%, and the free alkali content is all below 0.13%, which meets the standard of superior products in HG / T 4879-2016 "Sodium tert-butoxide for Industrial Use".

[0073] Supported metal-based catalysts may have a larger specific surface area and more active sites, thereby improving catalytic efficiency, making the reaction more complete, and the yield and purity higher. In addition, supported metal-based catalysts may also have better selectivity and stability, which can reduce the occurrence of side reactions. Alternative catalysts or catalyst components may lack the necessary activity or selectivity, resulting in incomplete reactions or the generation of more by-products, thereby affecting the yield, purity and product quality.

[0074] In summary, compared with Comparative Examples 1-4, the sodium tert-butoxide prepared in Examples 1-4 has better quality, higher yield, purity and reaction rate, and can accelerate the reaction.

[0075] In the description of the specification, the description with reference to the terms "preparation example", "embodiment", "various embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or preparation example are included in at least one embodiment or preparation example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or preparation example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or preparation examples in a suitable manner.

[0076] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A continuous production system for sodium tert-butoxide, characterized in that: The following steps are involved: S1. Pumping tert-butyl alcohol and sodium hydroxide from a raw material storage tank into a mixing kettle, stirring, preheating and mixing to obtain a preheated mixture; S2, loading the supported metal-based catalyst into the catalyst bed in the continuous reactor, pumping the preheated mixed material into the continuous reactor, stirring and heat-insulating the reaction to obtain a crude product, and providing a condensation reflux device on the top of the continuous reactor to recover the steam generated during the reaction; S3, the crude product is continuously discharged through the outlet at the bottom of the continuous reactor, and after distillation and purification in a distillation tower, a finished product is obtained; Wherein, the supported metal-based catalyst in step S2 comprises the following steps to prepare: A1. Mix boron nitride powder and metal oxide powder, add them into water containing 0.5-0.8wt% sodium dodecyl sulfate to form a suspension, adjust the pH value to 7-8, stir and heat to react, filter and wash, and dry to constant weight to obtain a modified metal oxide; A2. Add the modified metal oxide to a 20-30wt% sodium diethylenetriamine penta (methylenephosphonate) solution, add polyvinyl pyrrolidone, stir to react, filter, and perform heat treatment to obtain a supported metal-based catalyst.

2. A continuous production system for sodium tert-butoxide according to claim 1, characterized in that: In step S1, the stirring speed is 100-200 rpm, the preheating temperature is 70-75° C., and the mixing time is 5-15 min.

3. A continuous production system for sodium tert-butoxide according to claim 1, characterized in that: The feed mass ratio of tert-butyl alcohol, sodium hydroxide and supported metal-based catalyst is (5-7): (2-2.5): (0.08-0.18).

4. A continuous production system for sodium tert-butoxide according to claim 1, characterized in that: In step S2, the stirring speed is 300-400 rpm, the reaction temperature is 85-120° C., and the reaction time is 10-15 h.

5. A continuous production system for sodium tert-butoxide according to claim 1, characterized in that: In step A1, the mass ratio of boron nitride powder, metal oxide powder and water is (1-2): (5-7): (10-15), and the metal oxide includes one of iron oxide, cobalt oxide, nickel oxide, zinc oxide or magnesium oxide.

6. A continuous production system of sodium tert-butoxide according to claim 1, characterized in that: In step A1, the stirring speed is 200-300 rpm, the reaction temperature is 70-80° C., and the reaction time is 2-4 h.

7. A continuous production system of sodium tert-butoxide according to claim 1, characterized in that: In step A2, the mass ratio of the modified metal oxide, sodium diethylenetriamine penta (methylenephosphonate) solution and polyvinyl pyrrolidone is (2-4): (8-10): (0.15-0.35).

8. A continuous production system of sodium tert-butoxide according to claim 1, characterized in that: In step A2, the stirring speed is 300-400 rpm, the reaction time is 1-2 h, the heat treatment temperature is 80-100° C., and the heat treatment time is 6-8 h.

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