Method for synthesizing 3-aminopropanol by using propylene glycol and preparation method of D-panthenol

Abstract

The invention relates to a method for synthesizing 3-aminopropanol by using propylene glycol, in particular to a preparation method of D-panthenol. The method for synthesizing 3-aminopropanol by using propylene glycol comprises the following steps: mixing propylene glycol with a water-binding agent, introducing hydrogen chloride, and carrying out chlorination reaction to obtain 3-chloropropanol from reaction liquid; the method comprises the following steps: mixing liquid ammonia and ammonium chloride to form a base solution, then adding 3-chloropropanol into the base solution in batches to carry out primary ammonolysis reaction, after the reaction is finished, adding liquid ammonia into the reaction solution to carry out secondary ammonolysis reaction, and after the reaction is finished, carrying out deamination and rectification separation on the reaction solution to prepare 3-aminopropanol. The method for synthesizing the 3-aminopropanol by using the propylene glycol is simple, the energy consumption is reduced, and the prepared 3-aminopropanol is high in yield, high in purity and suitable for preparing D-panthenol.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing 3-aminopropanol by using propylene glycol and a method for preparing D-panthenol. Background Art

[0002] D-panthenol is an isotype of D-pantothenic acid, a precursor of coenzyme A, and an important vitamin drug. Once it enters the human body, it can be converted into pantothenic acid and then synthesized into coenzyme A, promoting the metabolism of protein, fat, and sugar in the human body, protecting the mucous membrane and luster of the skin surface, and preventing the occurrence of diseases. As a nutritional supplement, D-panthenol is widely used in the pharmaceutical, food, and cosmetics industries. Specific preparations include oral solutions, eye drops, multivitamin injections, shampoos, mousses, moisturizers, etc.

[0003] D-panthenol is usually synthesized using D-pantolactone and 3-aminopropanol as raw materials. Among them, the main methods for synthesizing 3-aminopropanol include acrylonitrile method, butyrolactone method, hydroxypropionitrile method, etc. However, these synthesis methods use acrylonitrile, 1,4-butyrolactone, and 3-hydroxypropionitrile as raw materials, respectively, and have problems such as complex synthesis methods, high energy consumption, low yield of 3-aminopropanol, and high impurity content. Summary of the invention

[0004] Based on this, it is necessary to provide a method for synthesizing 3-aminopropanol from propylene glycol and a method for preparing D-panthenol in order to solve the above problems. The present invention proposes a new method for synthesizing 3-aminopropanol from propylene glycol, which is not only simple in preparation and beneficial to reducing energy consumption, but also has high yield and purity of the prepared 3-aminopropanol, and is suitable for preparing D-panthenol.

[0005] A method for synthesizing 3-aminopropanol from propylene glycol comprises the following steps:

[0006] Propylene glycol and a water-binding agent are mixed and then introduced into hydrogen chloride for chlorination reaction to obtain 3-chloropropanol from the reaction solution;

[0007] Liquid ammonia and ammonium chloride are mixed to form a base liquid, and then the 3-chloropropanol is added to the base liquid in batches to carry out a first aminolysis reaction. After the reaction is completed, liquid ammonia is added to the reaction liquid again to carry out a second aminolysis reaction. After the reaction is completed, the reaction liquid is deaminated and distilled to obtain 3-aminopropanol.

[0008] In one embodiment, the molar ratio of liquid ammonia in the second ammonolysis reaction to liquid ammonia in the first ammonolysis reaction is (4-20):1.

[0009] In one embodiment, in the first ammonolysis reaction, the molar ratio of 3-chloropropanol to liquid ammonia and ammonium chloride is 1:(1-4):(1-6).

[0010] In one embodiment, the duration of adding the 3-chloropropanol in batches is 1 h to 6 h.

[0011] In one embodiment, the mass ratio of the propylene glycol to the water binding agent is (1.25-5):1;

[0012] And / or, the propylene glycol is selected from bio-based propylene glycol;

[0013] And / or, the water-binding agent is selected from at least one of sodium polyacrylate, molecular sieve, and anhydrous calcium chloride.

[0014] In one embodiment, after the chlorination reaction is completed, the water-binding agent is separated and recovered from the reaction solution and recycled for use in the chlorination reaction.

[0015] In one embodiment, after the second ammonolysis reaction is completed, the liquid ammonia is deaminated, separated and recovered from the reaction solution and recycled for use in the first ammonolysis reaction and / or the second ammonolysis reaction.

[0016] In one embodiment, after the second ammonolysis reaction is completed, after the reaction solution is deaminated and before distillation, ammonium chloride is separated by centrifugation and recycled for the first ammonolysis reaction.

[0017] In one embodiment, the temperature of the chlorination reaction is 40°C-110°C and the pressure is 0.11MPa-1MPa;

[0018] And / or, the temperature of the first ammonolysis reaction is 40°C-120°C and the pressure is 1MPa-5MPa;

[0019] And / or, the temperature of the second ammonolysis reaction is 20°C-40°C, the pressure is 1MPa-2MPa, and the time is 2h-8h.

[0020] A method for preparing D-panthenol comprises the following steps:

[0021] 3-aminopropanol is prepared by the method for synthesizing 3-aminopropanol from propylene glycol as described above;

[0022] The D-pantolactone and the 3-aminopropanol are mixed and reacted to obtain D-pantothenol.

[0023] The invention provides a novel method for synthesizing 3-aminopropanol by using propylene glycol. Propylene glycol and hydrogen chloride are subjected to chlorination reaction to generate 3-chloropropanol and water, and a water-binding agent is introduced to promote the chlorination reaction to proceed in the forward direction, thereby improving the yield of 3-chloropropanol. Meanwhile, by controlling the amount of liquid ammonia in the two-step ammonolysis reaction, 3-chloropropanol is firstly promoted to be converted into 3-aminopropanol hydrochloride with low nucleophilicity, thereby effectively reducing the generation of secondary amine impurities. After the 3-chloropropanol is completely converted, liquid ammonia is introduced to efficiently convert the 3-aminopropanol hydrochloride into 3-aminopropanol and ammonium chloride, thereby improving the yield and purity of 3-aminopropanol.

[0024] Therefore, the preparation method of the present invention is not only simple and easy to operate, but also beneficial to reducing energy consumption, and the prepared 3-aminopropanol has high yield and high purity, and is suitable for preparing D-panthenol. 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 recorded in 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 A schematic flow diagram of a method for synthesizing 3-aminopropanol using propylene glycol in one embodiment;

[0027] Figure 2 The gas chromatogram of 3-chloropropanol obtained in Example 1;

[0028] Figure 3 The gas chromatogram of 3-aminopropanol obtained in Example 1;

[0029] Figure 4 The gas chromatogram of 3-aminopropanol obtained in Comparative Example 1;

[0030] Figure 5 The gas chromatogram of 3-aminopropanol obtained in Comparative Example 2. DETAILED DESCRIPTION

[0031] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0033] Combination Figure 1 As shown, a method for synthesizing 3-aminopropanol from propylene glycol provided by the present invention comprises the following steps:

[0034] S1, mixing propylene glycol and a water-binding agent, and then introducing hydrogen chloride into the mixture for chlorination reaction, thereby obtaining 3-chloropropanol from the reaction solution;

[0035] S2, mixing liquid ammonia and ammonium chloride to form a base liquid, then adding the 3-chloropropanol to the base liquid in batches to carry out a first aminolysis reaction, and after the reaction is completed, adding liquid ammonia to the reaction liquid to carry out a second aminolysis reaction, and after the reaction is completed, the reaction liquid is deaminated and distilled to obtain 3-aminopropanol.

[0036] In step S1, as shown in formula (1), propylene glycol and hydrogen chloride are reacted by chlorination to generate 3-chloropropanol and water. Since the chlorination reaction is a reversible reaction, the water generated by the reaction will cause the chlorination reaction to proceed in reverse and reduce the yield of 3-chloropropanol. By introducing a water-binding agent, the water content can be reduced, the reverse reaction can be prevented, and the chlorination reaction can be promoted in the forward direction, which not only improves the yield of 3-chloropropanol, but also reduces the corrosion of the reaction device by free chloride ions, avoids post-treatment processes, and reduces energy consumption.

[0037]

[0038] In one embodiment, the mass ratio of the propylene glycol to the water binding agent is preferably (1.25-5):1, including but not limited to any point value of 1.25:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or a range value between any two of them.

[0039] In one embodiment, the propylene glycol includes but is not limited to bio-based propylene glycol, preferably bio-based propylene glycol. When bio-based propylene glycol is used for reaction, bio-based 3-aminopropanol is obtained. When bio-based 3-aminopropanol and D-pantolactone prepared by fermentation are reacted, all-bio-based D-panthenol is obtained. Compared with non-bio-based D-panthenol, bio-based D-panthenol is free from dependence on fossil raw materials, is more environmentally friendly, and better meets the requirements of sustainable development.

[0040] In one embodiment, the water-binding agent includes but is not limited to at least one of sodium polyacrylate, molecular sieves, and anhydrous calcium chloride.

[0041] In one embodiment, after the chlorination reaction is completed, the water-binding agent is separated and recovered from the reaction solution and recycled for use in the chlorination reaction, thereby improving the utilization rate of the water-binding agent and helping to reduce the preparation cost.

[0042] In one embodiment, the temperature of the chlorination reaction is 40°C-110°C, preferably 60°C-100°C; the pressure of the chlorination reaction can be controlled by adjusting the flow rate of hydrogen chloride, and the pressure is preferably 0.11MPa-1MPa, more preferably 0.11MPa-0.5MPa. It can be understood that the pressure of the chlorination reaction is an absolute pressure; the present invention does not limit the time of the chlorination reaction, and the reaction endpoint is reached when the gas phase monitoring shows that propylene glycol is completely converted.

[0043] In step S2, as shown in formula (2), in the two-step ammonolysis reaction process, by controlling the amount of liquid ammonia used twice, part of the liquid ammonia is first introduced to promote the conversion of 3-chloropropanol into 3-aminopropanol hydrochloride with low nucleophilicity, effectively hinder the generation of 3-aminopropanol with high nucleophilicity, thereby reducing the secondary amine impurities generated by the reaction of 3-aminopropanol with high nucleophilicity and 3-chloropropanol; after the 3-chloropropanol is completely converted, liquid ammonia is introduced again to efficiently convert the 3-aminopropanol hydrochloride into 3-aminopropanol and ammonium chloride, thereby improving the yield and purity of 3-aminopropanol.

[0044]

[0045] Preferably, the molar amount of liquid ammonia in the second ammonolysis reaction is greater than the molar amount of liquid ammonia in the first ammonolysis reaction.

[0046] Further preferably, the molar ratio of liquid ammonia in the second ammonolysis reaction to the liquid ammonia in the first ammonolysis reaction is (4-20):1, including but not limited to any point value among 4:1, 5:1, 6:1, 7:1, 8:1, 10:1, 12:1, 15:1, 16:1, 18:1, 20:1 or the range value between any two thereof.

[0047] In one embodiment, in the first ammonolysis reaction, the molar ratio of 3-chloropropanol to liquid ammonia and ammonium chloride is 1:(1-4):(1-6), including but not limited to 1:4:1, 1:4:2, 1:4:4, 1:4:6, 1:3:1, 1:3:3, 1:3:5, 1:2:1, 1:2:2, 1:2:4, 1:2:6, 1:1:1, 1:1:2, 1:1:5, 1:1:6, or any range between any two of them.

[0048] In one embodiment, the duration of adding the 3-chloropropanol in batches is 1h-6h, and preferably, the 3-chloropropanol is added in batches by dropwise addition. It is understandable that, on the basis of the same raw material ratio, when the mass of the base liquid is larger, the mass of the 3-chloropropanol added in each batch is relatively improved. Therefore, by controlling the time of the 3-chloropropanol added in batches, the amount of each batch of 3-chloropropanol added is regulated, so that under the same ratio but different base liquid masses, the first aminolysis reaction can be carried out efficiently and positively.

[0049] In one embodiment, the temperature of the first ammonolysis reaction is 40°C-120°C, preferably 60°C-100°C; the pressure is 1MPa-5MPa, preferably 1.5MPa-3.5MPa. It should be noted that the present invention does not limit the time of the first ammonolysis reaction, and the reaction endpoint is reached when the gas phase monitoring shows that 3-chloropropanol is completely converted.

[0050] In one embodiment, after the second ammonolysis reaction is completed, the liquid ammonia is recovered by deammoniation separation from the reaction liquid and recycled for use in the first ammonolysis reaction and / or the second ammonolysis reaction, thereby improving the utilization rate of the liquid ammonia and helping to reduce the preparation cost.

[0051] In one embodiment, after the second ammonolysis reaction is completed, after the reaction solution is deaminated and before distillation separation, ammonium chloride is separated by centrifugation and recycled for the first ammonolysis reaction, thereby improving the utilization rate of ammonium chloride and helping to reduce the preparation cost.

[0052] In one embodiment, the temperature of the second aminolysis reaction is 20°C-40°C, the pressure is 1MPa-2MPa, and the time is 2h-8h.

[0053] Therefore, the preparation method of the present invention is not only simple and easy to operate, but also beneficial to reducing energy consumption, and the prepared 3-aminopropanol has high yield and high purity, and is suitable for preparing D-panthenol.

[0054] The present invention also provides a method for preparing D-panthenol, comprising the following steps:

[0055] S1, preparing 3-aminopropanol by the method for synthesizing 3-aminopropanol from propylene glycol as described above;

[0056] S2, mixing D-pantolactone and the 3-aminopropanol for reaction to obtain D-panthenol.

[0057] It should be noted that the present invention does not limit the reaction process of D-pantolactone and 3-aminopropanol, that is, the preparation method of 3-aminopropanol provided by the present invention can be applied to the existing reaction process of D-pantolactone and 3-aminopropanol, thereby realizing the efficient production of D-pantolactone, reducing the preparation cost of D-pantolactone, and further improving the industrial production of D-pantolactone.

[0058] Preferably, the temperature for the mixed reaction of D-pantolactone and the 3-aminopropanol is 30°C-120°C.

[0059] Hereinafter, the method for synthesizing 3-aminopropanol from propylene glycol and the method for preparing D-panthenol will be further described by the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0060] Example 1

[0061] Propylene glycol (500 g, 6.58 mol) and 200 g of dry activated 3A molecular sieve were added to the chlorination reaction kettle, the temperature was raised to 80°C and kept constant, hydrogen chloride was introduced to keep the pressure in the reactor at 0.3 MPa, the reaction was continued for 6 hours, and the yield of 3-chloropropanol was 95%. The reaction liquid was filtered and the 3A molecular sieve was recovered and activated and then used, and the remaining reaction liquid was distilled to obtain 581.1 g of 3-chloropropanol with a purity of 99.6%. The obtained 3-chloropropanol was tested by gas chromatography, and the results were as follows: Figure 2 shown.

[0062] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted. The reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 94.2%. The reaction liquid was deaminated to recover liquid ammonia for reuse, the reaction liquid was centrifuged to recover ammonium chloride, and the remaining reaction liquid was distilled to obtain 424.1 g of 3-aminopropanol with a purity of 100%. The obtained 3-aminopropanol was subjected to gas chromatography test, and the results were as follows: Figure 3 shown.

[0063] Example 2

[0064] 3-Chloropropanol was prepared by the same method as in Example 1.

[0065] Liquid ammonia (260.7g, 15.3mol) and ammonium chloride (818.6g, 15.3mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1g, 6.12mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to room temperature 30°C, the pressure was stabilized at 1.17MPa, and liquid ammonia (1664.8g, 97.7mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 92.1%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 415.5g of 3-aminopropanol with a purity of 99.8%.

[0066] Example 3

[0067] 3-Chloropropanol was prepared by the same method as in Example 1.

[0068] Liquid ammonia (365.0 g, 21.42 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 89.5%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 403.7 g of 3-aminopropanol with a purity of 99.8%.

[0069] Example 4

[0070] 3-Chloropropanol was prepared by the same method as in Example 1.

[0071] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (491.1 g, 9.18 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 89.9%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 405.1 g of 3-aminopropanol with a purity of 99.9%.

[0072] Example 5

[0073] 3-Chloropropanol was prepared by the same method as in Example 1.

[0074] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (1964.5 g, 36.72 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 94.9%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 427.2 g of 3-aminopropanol with a purity of 100%.

[0075] Example 6

[0076] 3-Chloropropanol was prepared by the same method as in Example 1.

[0077] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 40°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 85.4%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 386.4 g of 3-aminopropanol with a purity of 99.5%.

[0078] Example 7

[0079] 3-Chloropropanol was prepared by the same method as in Example 1.

[0080] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 120°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 93.6%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 421.8 g of 3-aminopropanol with a purity of 99.9%.

[0081] Example 8

[0082] 3-Chloropropanol was prepared by the same method as in Example 1.

[0083] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 1 hour, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.7 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 88.5%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 400.0 g of 3-aminopropanol with a purity of 99.6%.

[0084] Example 9

[0085] 3-Chloropropanol was prepared by the same method as in Example 1.

[0086] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 6 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.17 MPa, and liquid ammonia (1664.8 g, 97.92 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 94.5%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 425.4 g of 3-aminopropanol with a purity of 100%.

[0087] Example 10

[0088] 3-Chloropropanol was prepared by the same method as in Example 1.

[0089] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.15 MPa, and liquid ammonia (1040.4 g, 61.2 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 80.4%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 364.9 g of 3-aminopropanol with a purity of 99.2%.

[0090] Embodiment 11

[0091] 3-Chloropropanol was prepared by the same method as in Example 1.

[0092] Liquid ammonia (156.4 g, 9.18 mol) and ammonium chloride (818.6 g, 15.3 mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1 g, 6.12 mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2 MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to 30°C, the pressure was stabilized at 1.21 MPa, and liquid ammonia (3121.2 g, 183.6 mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 95.9%. The reaction liquid was deaminated and liquid ammonia was recovered for reuse. The reaction liquid was centrifuged to recover ammonium chloride. The remaining reaction liquid was distilled to obtain 431.7 g of 3-aminopropanol with a purity of 100%.

[0093] Example 12

[0094] 500g of bio-based propylene glycol and 300g of anhydrous calcium chloride were added to the chlorination reaction kettle, the temperature was raised to 60°C and kept constant, hydrogen chloride was introduced to keep the pressure in the reactor at 0.5MPa, the reaction was continued for 6h, and the yield of 3-chloropropanol was 89.2%. The reaction liquid was filtered and distilled to obtain 547.9g of 3-chloropropanol with a purity of 99.2%.

[0095] Liquid ammonia (245.0 g, 14.38 mol) and ammonium chloride (769.2 g, 14.38 mol) were added to an ammonolysis reactor, the temperature was raised to 80°C, 3-chloropropanol (547.9 g, 5.75 mol) was added dropwise into the reactor within 4 hours, the pressure was stabilized at 4 MPa, and 3-chloropropanol was completely converted after 2.5 hours; the reactor was cooled to 35°C, liquid ammonia (1564.4 g, 91.8 mol) was introduced into the reactor, and after reacting for 5 hours, the yield of 3-aminopropanol was 92.2%, and 390.9 g of 3-aminopropanol was obtained after distillation with a purity of 99.7%.

[0096] The 3-aminopropanol prepared in Examples 1 to 12 was used to prepare D-panthenol. The specific method was as follows: preheated and melted D-pantolactone (443.0 g, 3.40 mol) was added dropwise to 3-aminopropanol (255.6 g, 3.40 mol, calculated on a pure basis) at 60° C. After reacting for 3 hours, D-panthenol was obtained without treatment, and the purity was as high as 99.7%.

[0097] Comparative Example 1

[0098] 3-Chloropropanol was prepared by the same method as in Example 1.

[0099] 25wt% ammonia water (359.8g, 5.3mol) and 3-chloropropanol (201.3g, 2.12mol) were added to an ammonolysis reactor and heated to 80°C. After 6h, 3-chloropropanol was completely converted. At this time, 3-aminopropanol existed in the form of hydrochloride. 424g, 20wt% NaOH aqueous solution was used to neutralize free chloride ions. After evaporation and removal of water, sodium chloride was filtered out. The yield of 3-aminopropanol measured by internal standard was 64.2%. The gas chromatography test results are as follows: Figure 4 As shown, 102.2 g of 3-aminopropanol was obtained after distillation with a purity of 97.9%.

[0100] Comparative Example 2

[0101] 3-Chloropropanol was prepared by the same method as in Example 1.

[0102] Liquid ammonia (181.5 g, 10.65 mol) was first introduced into the ammonolysis reactor. At 80°C, 3-chloropropanol (58.1 g, 0.61 mol) was added dropwise into the reactor and the pressure was stabilized at 3 MPa. After 3 hours, 3-chloropropanol was completely converted. At this time, 3-aminopropanol existed in the form of hydrochloride. 122.4 g, 20 wt% NaOH aqueous solution was used to neutralize free chloride ions. After evaporation and removal of water, sodium chloride was filtered out. The yield of 3-aminopropanol measured by internal standard was 75.8%. The gas chromatography test results are as follows: Figure 5 As shown, 34.3 g of 3-aminopropanol was obtained after distillation with a purity of 99.1%.

[0103] Comparative Example 3

[0104] 3-Chloropropanol was prepared by the same method as in Example 1.

[0105] Liquid ammonia (1664.8g, 97.7mol) and ammonium chloride (818.5g, 15.3mol) were added to the ammonolysis reactor, and the temperature was raised to 80°C. 3-chloropropanol (581.1g, 6.12mol) was added dropwise to the reactor within 4 hours, and the pressure was stabilized at 2MPa. After 4 hours, 3-chloropropanol was completely converted; the reactor was cooled to room temperature, and liquid ammonia (365.0g, 21.4mol) was introduced into the reactor. After 4 hours of reaction, the yield of 3-aminopropanol was 79.4%. The reaction liquid was deaminated to recover liquid ammonia for reuse, the reaction liquid was centrifuged to recover ammonium chloride, and the remaining reaction liquid was distilled to obtain 360.4g of 3-aminopropanol with a purity of 99.1%.

[0106] The amount of liquid ammonia used in the primary ammonolysis reaction of Comparative Example 3 is much greater than that in the secondary ammonolysis reaction, resulting in the main generation of highly nucleophilic 3-aminopropanol from 3-chloropropanol during the primary ammonolysis reaction. In addition, since the highly nucleophilic 3-aminopropanol competes with liquid ammonia for 3-chloropropanol, the secondary amine impurity content is high, resulting in a low yield of 3-aminopropanol.

[0107] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for synthesizing 3-aminopropanol from propylene glycol, characterized in that: The method comprises the following steps: Propylene glycol and a water-binding agent are mixed and then introduced into hydrogen chloride for chlorination reaction to obtain 3-chloropropanol from the reaction solution; Liquid ammonia and ammonium chloride are mixed to form a base liquid, and then the 3-chloropropanol is added to the base liquid in batches to carry out a first aminolysis reaction. After the reaction is completed, liquid ammonia is added to the reaction liquid again to carry out a second aminolysis reaction. After the reaction is completed, the reaction liquid is deaminated and distilled to obtain 3-aminopropanol.

2. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: The molar ratio of liquid ammonia in the second ammonolysis reaction to liquid ammonia in the first ammonolysis reaction is (4-20):

1.

3. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: In the first ammonolysis reaction, the molar ratio of 3-chloropropanol to liquid ammonia and ammonium chloride is 1:(1-4):(1-6).

4. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: The duration of adding the 3-chloropropanol in batches is 1 h to 6 h.

5. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: The mass ratio of the propylene glycol to the water binding agent is (1.25-5):1; And / or, the propylene glycol is selected from bio-based propylene glycol; And / or, the water-binding agent is selected from at least one of sodium polyacrylate, molecular sieve, and anhydrous calcium chloride.

6. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: After the chlorination reaction is completed, the water-binding agent is separated and recovered from the reaction solution and recycled for use in the chlorination reaction.

7. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: After the second ammonolysis reaction is completed, the liquid ammonia is deaminated, separated and recovered from the reaction solution, and recycled for use in the first ammonolysis reaction and / or the second ammonolysis reaction.

8. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: After the second ammonolysis reaction is completed, the ammonium chloride is separated by centrifugation after the reaction solution is deaminated and before distillation and separation, and is recycled for the first ammonolysis reaction.

9. The method for synthesizing 3-aminopropanol from propylene glycol according to claim 1, characterized in that: The temperature of the chlorination reaction is 40°C-110°C and the pressure is 0.11MPa-1MPa; And / or, the temperature of the first ammonolysis reaction is 40°C-120°C and the pressure is 1MPa-5MPa; And / or, the temperature of the second ammonolysis reaction is 20°C-40°C, the pressure is 1MPa-2MPa, and the time is 2h-8h.

10. A method for preparing D-panthenol, characterized in that: The steps include: 3-aminopropanol is prepared by the method for synthesizing 3-aminopropanol from propylene glycol as described in any one of claims 1 to 9; The D-pantolactone and the 3-aminopropanol are mixed and reacted to obtain D-pantothenol.

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