CN112174836A

CN112174836A - Synthetic method of aminobutanol

Info

Publication number: CN112174836A
Application number: CN202011220522.4A
Authority: CN
Inventors: 吴法浩; 李钢; 高仰哲; 王志航
Original assignee: Nanjing Redwood Fine Chemical Co ltd
Current assignee: Nanjing Redwood Fine Chemical Co ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-01-05

Abstract

The invention discloses a method for synthesizing aminobutanol, belonging to the technical field of organic synthesis. The synthesis method comprises the following steps: heating 4-hydroxy-2-butanone oxime and formic acid or acetic acid to react in the presence of a catalyst, wherein the catalyst is zinc. The synthesis method provided by the application adopts the butyl ketol as the initial raw material, is low in cost, does not use Raney nickel but uses zinc as the catalyst, is low in cost and high in yield, does not need to be carried out in an oxygen-free environment and under high pressure, is mild in reaction condition, simple in catalyst storage and subsequent treatment, and good in economic benefit, and is suitable for industrial production.

Description

Synthetic method of aminobutanol

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing aminobutanol.

Background

The existing method for preparing the aminobutanol adopts 3-aminobutyric acid or 3-aminobutyrate ethyl ester to directly reduce and prepare the 3-amino-1-butanol, and the used raw materials are expensive and are not beneficial to cost control. Some ketol is adopted as a starting material, however, Raney nickel is adopted as a catalyst in the preparation process, the process is difficult to control, the safety is low, the cost is high, and the production is not facilitated.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a method for synthesizing aminobutanol so as to solve the technical problem.

The application can be realized as follows:

the application provides a synthetic method of aminobutanol, which comprises the following steps: heating 4-hydroxy-2-butanone oxime and formic acid or acetic acid to react in the presence of catalyst. The catalyst is zinc.

In an alternative embodiment, the mass ratio of catalyst to 4-hydroxy-2-butanone oxime is 1-2.5: 1.

In an alternative embodiment, the mass ratio of catalyst to 4-hydroxy-2-butanone oxime is 2-2.5: 1.

In an alternative embodiment, the amount ratio of 4-hydroxy-2-butanone oxime to formic acid or acetic acid is 100 g: 1.5-2.5L, wherein the formic acid or the acetic acid is provided in the form of a formic acid solution or an acetic acid solution, and the volume concentration of the formic acid solution or the acetic acid solution is 45-55%.

In an alternative embodiment, the reaction is heated at a temperature of 110 to 120 ℃ for a time of 4 to 9 hours. Preferably, heating to reflux.

In an alternative embodiment, after the reaction is finished, a zinc removal step is further included.

In an alternative embodiment, the dezincification is carried out by introducing H₂The method of S is carried out.

In an alternative embodiment, solid-liquid separation is performed after zinc removal, and the first extraction is performed after the solvent in the separated liquid is removed.

In an alternative embodiment, the pH is adjusted to not less than 11 before the first extraction is performed.

In an alternative embodiment, the extractant of the first extraction comprises at least one of ethyl acetate, dichloromethane, and diethyl ether.

In an alternative embodiment, the number of first extractions is 1 to 3, and when the number is 3, the amount of extractant used per extraction is 150 to 180 mL.

In an alternative embodiment, after the first extraction, drying the ester layer after the first extraction is further included.

In alternative embodiments, the drying agent used for drying comprises anhydrous sodium sulfate or anhydrous magnesium sulfate.

In an alternative embodiment, 4-hydroxy-2-butanone oxime is prepared in the following manner:

reacting the butyl ketol with hydroxylamine in the presence of alkali, cooling and reacting with inorganic acid after the reaction is finished, and then performing second extraction to remove the solvent in the extract.

In an alternative embodiment, the base used in the reaction of the butanonol with the hydroxylamine comprises NaOH and Na₂CO₃At least one of (1).

In an alternative embodiment, the base is NaOH.

In an alternative embodiment, when the base used in the reaction of butanone alcohol and hydroxylamine is NaOH, the concentration of NaOH is 2 to 5 mol/L.

In an alternative embodiment, the concentration of NaOH is 4-5 mol/L.

In an alternative embodiment, the ratio of the amount of butanonol to base is 130 g: 500-600 mL.

In an alternative embodiment, the hydroxylamine comprises at least one of hydroxylamine hydrochloride, hydroxylamine phosphate and hydroxylamine sulfate.

In an alternative embodiment, the hydroxylamine is hydroxylamine hydrochloride.

In an alternative embodiment, when the hydroxylamine is hydroxylamine hydrochloride, the molar ratio of the butanolic alcohol to hydroxylamine hydrochloride is from 1:1 to 1.3.

In an alternative embodiment, the molar ratio of butanols to hydroxylamine hydrochloride is from 1:1.2 to 1.3.

In an alternative embodiment, the butanols are reacted with hydroxylamine at 55-65 ℃ for 25-35 min.

In an alternative embodiment, the reaction of the butanols with hydroxylamines is carried out under stirring conditions.

In an alternative embodiment, the reaction with the mineral acid is carried out after cooling to 25-30 ℃.

In an alternative embodiment, the mineral acid comprises at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

In an alternative embodiment, when the mineral acid is hydrochloric acid, the amount ratio of hydrochloric acid to butanonol is 420-460 mL: 130g, and the concentration of hydrochloric acid is 4.5-5.5 mol/L.

In an alternative embodiment, the extractant of the second extraction comprises at least one of ethyl acetate, dichloromethane, and diethyl ether.

In an alternative embodiment, the number of second extractions is 1 to 3, and when the number is 3, the amount of extractant used per extraction is 180 to 220 mL.

In an alternative embodiment, the solvent is removed from the extract by concentrating the extract at 35-40 deg.C to dryness.

The beneficial effect of this application includes:

the synthesis method of the aminobutanol provided by the application adopts the butyl ketol as the starting material, and is low in cost. The method has the advantages of no use of Raney nickel and use of zinc as a catalyst in the synthesis process, low cost, high yield, no need of performing the reaction in an oxygen-free environment and under high pressure, mild reaction conditions, simple storage and subsequent treatment of the catalyst, good economic benefit and suitability for industrial production.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a scheme showing the synthesis of aminobutanol in the present application;

FIG. 2 is a scheme showing the synthesis of aminobutanol in example 1 of the present application;

FIG. 3 is a high performance liquid chromatogram of aminobutanol prepared in example 1 of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The following is a detailed description of the method for synthesizing aminobutanol provided in the present application.

The cost of the existing synthesis process of the aminobutanol is high, and the industrial value of the aminobutanol is seriously influenced. The reason for this is mainly that the conventional aminobutanol cannot be used both as a raw material and as a catalyst. In order to reduce the cost of raw materials, part of synthesis methods adopt butyl ketol as a starting raw material, but cannot avoid using Raney nickel as a catalyst in the later period to prepare products through catalytic hydrogenation. The raney nickel can generate oxidation reaction even spontaneous combustion when exposed to air, and the reaction of the raney nickel in strong acid releases hydrogen, the generated dust is combustible, and an explosive mixture can be formed with air. The corresponding process needs to be carried out in an oxygen-free environment, the hydrogenation reaction also needs to be carried out under high pressure, and the reaction conditions are harsh. In addition, the catalyst raney nickel is troublesome to preserve and post-treat, and is not favorable for production. In order to avoid the problems in the production, 3-aminobutyric acid or 3-aminobutyrate ethyl ester is directly reduced to prepare 3-amino-1-butanol, and the raw materials are expensive and are not beneficial to cost control.

The inventors have creatively proposed a solution to the above problem through long-term research and practice: namely, 4-hydroxy-2-butanone oxime and formic acid or acetic acid are heated and reacted in the presence of a catalyst to obtain aminobutanol. The catalyst is zinc. The synthetic route can refer to FIG. 1.

By using zinc as a catalyst, the method has the advantages of high catalytic efficiency, high yield and mild reaction conditions, and can also greatly reduce the production cost and improve the economic benefit.

In alternative embodiments, the mass ratio of catalyst to 4-hydroxy-2-butanone oxime may be 1-2.5:1, such as 1:1, 1:1.5, 1:2, or 1:2.5, etc.

In a preferred embodiment, the mass ratio of the catalyst to the 4-hydroxy-2-butanone oxime is 2-2.5:1, and more preferably, the mass ratio of the catalyst to the 4-hydroxy-2-butanone oxime is 1: 2.5.

In an alternative embodiment, the amount ratio of 4-hydroxy-2-butanone oxime to formic acid or acetic acid may be 100 g: 1.5-2.5L, such as 100 g: 1.5L, 100 g: 2L or 100 g: 2.5L, etc. Wherein, the formic acid or acetic acid is provided in the form of formic acid solution or acetic acid solution, and the volume concentration of the formic acid solution or acetic acid solution can be 45-55%, such as 45%, 50% or 55%, etc.

In the present application, the temperature of the heating reaction may be 110-120 ℃, such as 110 ℃, 115 ℃ or 120 ℃. The heating reaction time can be 4-9h, such as 4h, 5h, 6h, 7h, 8h or 9 h. Preferably, heating to reflux.

Further, after the reaction is finished, a zinc removing step is also included.

In an alternative embodiment, the zinc removal can be carried out by passing H through₂The method of S is carried out. By the method, the obtained by-product zinc sulfide is insoluble and is easy to filter, and the zinc sulfide can be further used or sold, so that a certain additional value is brought to the preparation process.

Further, after zinc removal, solid-liquid separation (e.g., filtration) is performed, and after the solvent in the liquid (e.g., filtrate) obtained after the separation is removed, the first extraction is performed.

Removal of the solvent may, for reference, be carried out in concentrated, evaporated form.

Preferably, before the first extraction (NaOH or Na is used)₂CO₃) The pH of the extract is adjusted to not less than 11. Specifically, the concentrated solution may be added with 450-550mL of water, and then NaOH or Na₂CO₃The pH value is adjusted.

In an alternative embodiment, the extractant of the first extraction may comprise, for example, at least one of ethyl acetate, dichloromethane, and diethyl ether, preferably ethyl acetate.

In an alternative embodiment, the number of times of the first extraction may be 1-3, and when the number of times is 3, the amount of the extractant used per time is 150-180mL, such as 150mL, 160mL, 170mL or 180 mL. It is worth mentioning that in practice the number of first extractions may also exceed 3.

Further, after the first extraction, drying the ester layer after the first extraction.

In alternative embodiments, the drying agent used for drying comprises anhydrous sodium sulfate or anhydrous magnesium sulfate. The drying time can be 25-40min, such as 25min, 30min, 35min or 40 min.

Further, drying may be followed by further concentration, and concentration in this process may be carried out at 42-48 deg.C (e.g., 45 deg.C).

In the application, the 4-hydroxy-2-butanone oxime can be prepared in the following way:

In an alternative embodiment, the base used in the reaction of the butanonol with the hydroxylamine comprises NaOH and Na₂CO₃At least one of (1). In a preferred embodiment, the base is NaOH. Since the reaction of butanone and hydroxylamine to produce oxime is a reversible process, the reaction can be carried out smoothly by adjusting with alkali to ensure normal reaction.

In alternative embodiments, when the base used in the reaction of the butanone alcohol and hydroxylamine is NaOH, the concentration of NaOH may be 2 to 5mol/L, such as 2mol/L, 3mol/L, 4mol/L, or 5 mol/L. Preferably, the concentration of NaOH is 4-5mol/L, such as 4mol/L, 4.5mol/L or 5 mol/L.

In an alternative embodiment, the ratio of the amount of butanolone to base may be 130 g: 500-600mL, such as 130 g: 500mL, 130 g: 550mL or 130 g: 600mL, etc.

In alternative embodiments, the hydroxylamine may include, for example, at least one of hydroxylamine hydrochloride, hydroxylamine phosphate, and hydroxylamine sulfate. In a preferred embodiment, the hydroxylamine is hydroxylamine hydrochloride.

In alternative embodiments, when the hydroxylamine is hydroxylamine hydrochloride, the molar ratio of the butanolic alcohol to hydroxylamine hydrochloride can be from 1:1 to 1.3, such as 1:1, 1:1.1, 1:1.2, or 1:1.3, and the like. In a preferred embodiment, the molar ratio of butanols to hydroxylamine hydrochloride is from 1:1.2 to 1.3, more preferably 1: 1.2.

In an alternative embodiment, the butanols are reacted with hydroxylamines at 55-65 deg.C (e.g., 55 deg.C, 60 deg.C, or 65 deg.C, etc.) for 25-35min (e.g., 25min, 30min, or 35min, etc.).

Preferably, the reaction of the butanols with the hydroxylamines is carried out under stirring conditions.

Hydroxyl in hydroxylamine hydrochloride can be liberated out to carry out condensation reaction with butanone alcoholate by reacting butanone alcoholate with hydroxylamine in an alkali solution at 55-65 ℃.

In the application, after the reaction between the butyl ketol and the hydroxylamine, the temperature is reduced to 25-30 ℃ and then the butyl ketol reacts with the inorganic acid, so that the problem that the safety in the synthesis process is influenced because the butyl ketol directly reacts with the inorganic acid without being cooled to release a large amount of heat is avoided.

In alternative embodiments, the inorganic acid used herein includes at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

In an alternative embodiment, when the mineral acid is hydrochloric acid, the ratio of the amount of hydrochloric acid to butanonol may be 420-460 mL: 130g, such as 420 mL: 130g, 430 mL: 130g, 440 mL: 130g, 450 mL: 130g or 460 mL: 130g, and the like. The concentration of the corresponding hydrochloric acid may be 4.5-5.5mol/L, such as 4.5mol/L, 5mol/L, or 5.5mol/L, etc.

In an alternative embodiment, the extractant of the second extraction may comprise at least one of ethyl acetate, dichloromethane and diethyl ether, preferably diethyl ether.

In an alternative embodiment, the number of times of the second extraction may be 1 to 3, and when the number of times is 3, the amount of the extractant used per time is 180 to 220mL, such as 180mL, 200mL or 220 mL. It is worth mentioning that in practice the number of second extractions may also exceed 3.

In an alternative embodiment, the solvent in the extract after the second extraction can be removed by concentrating the extract at 35-40 deg.C (e.g., 35 deg.C) and evaporating to dryness.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

Referring to FIG. 2, 130g of butanol is added into 550mL of NaOH solution (4mol/L), 123g of hydroxylamine hydrochloride is added, the temperature is raised to 60 ℃, the stirring is carried out for 30min, the temperature is reduced to normal temperature (25-30 ℃), 440mL of hydrochloric acid (5mol/L) is added into the solution, ether is used for extraction for 3 times and 200 mL/time, the extract is concentrated at 35 ℃ until no solvent is evaporated, and 120.6g of 4-hydroxy-2-butanone oxime is obtained, the yield is 91.8%, and the purity is 98.1%.

Taking 100g of the 4-hydroxy-2-butanone oxime, adding 2L of 50vt percent acetic acid and 200g of zinc powder, heating to 115 ℃, refluxing for 7H, and introducing H after the reaction is finished₂S2 h, removing zinc, filtering, concentrating the filtrate to evaporate the solvent, adding 500mL of water into the concentrate, adjusting the pH to be more than 11 by using sodium hydroxide, extracting the product by using ethyl acetate for 3 times and 150 mL/time, and drying the product for 30min by using anhydrous sodium sulfate. Concentration at 45 ℃ gave 109.8g of aminobutanol at 89.5% yield.

The purity of the aminobutanol obtained in this example was tested by high-phase liquid chromatography, and the high performance liquid chromatogram obtained is shown in fig. 3.

The detection wavelength for channel 1 of detector a in fig. 3 corresponds to 210 nm.

The results of the obtained chromatographic peaks are shown in table 1, wherein the peak numbers 1 to 4 correspond to 4 chromatographic peaks from left to right in fig. 1, respectively.

TABLE 1 chromatographic Peak results

Peak number	Retention time	Area of	Height	Area%	Height%
						1	2.057	56966	12506	0.257	0.720
2	2.746	178059	32567	0.802	1.874
						3	4.421	21842864	1678796	98.878	96.609
4	7.404	14065	1333	0.063	0.077
						Total of		22203168	1737730	100.000	100.000

As can be seen from table 1 and fig. 3, the purity of the aminobutanol obtained by this example was 98.8%.

Example 2

This example differs from example 1 in that: in the reaction process of the butyl ketone alcohol and the hydroxylamine hydrochloride, NaOH is changed from Na₂CO₃Instead.

The yield of the aminobutanol obtained was 83.3% and the purity 98.1%.

Example 3

This example differs from example 1 in that: in the reaction process of the butyl ketone alcohol and the hydroxylamine hydrochloride, the concentration of NaOH is 2 mol/L.

The yield of the aminobutanol obtained was 85.6% and the purity was 95.6%.

Example 4

This example differs from example 1 in that: in the reaction process of the butyl ketone alcohol and the hydroxylamine hydrochloride, the concentration of NaOH is 3 mol/L.

The yield of the aminobutanol obtained was 87.8% and the purity was 97.5%.

Example 5

This example differs from example 1 in that: in the reaction process of the butyl ketone alcohol and the hydroxylamine hydrochloride, the concentration of NaOH is 5 mol/L.

The yield of the aminobutanol obtained was 91.5% and the purity 98.0%.

Example 6

This example differs from example 1 in that: hydroxylamine hydrochloride was replaced by hydroxylamine phosphate.

The yield of the aminobutanol obtained was 56.5% and the purity was 88.5%.

Example 7

This example differs from example 1 in that: hydroxylamine sulfate is used to replace hydroxylamine hydrochloride.

The yield of the aminobutanol obtained was 48.7% and the purity was 75.9%.

Example 8

This example differs from example 1 in that: in the reaction process of the butanol and the hydroxylamine hydrochloride, the molar ratio of the butanol to the hydroxylamine hydrochloride is 1:1.

The yield of the aminobutanol obtained was 85.8% with a purity of 98%.

Example 9

This example differs from example 1 in that: in the reaction process of the butanol and the hydroxylamine hydrochloride, the molar ratio of the butanol to the hydroxylamine hydrochloride is 1: 1.1.

The yield of the aminobutanol obtained was 87.6% and the purity 98.4%.

Example 10

This example differs from example 1 in that: in the reaction process of the butanol and the hydroxylamine hydrochloride, the molar ratio of the butanol to the hydroxylamine hydrochloride is 1: 1.3.

The yield of the aminobutanol obtained was 91.0% and the purity 98.5%.

Example 11

This example differs from example 1 in that: the extractant used in the preparation process of the 4-hydroxy-2-butanone oxime is ethyl acetate.

The yield of aminobutanol obtained was 45.9%.

Example 12

This example differs from example 1 in that: the extractant used in the preparation process of the 4-hydroxy-2-butanone oxime is dichloromethane.

The yield of aminobutanol obtained was 39.1%.

Example 13

This example differs from example 1 in that: 4-hydroxy-2-butanone oxime and formic acid are subjected to reflux reaction under the condition that zinc is used as a catalyst.

The yield of the aminobutanol obtained was 78.4% and the purity was 96.7%.

Example 14

This example differs from example 1 in that: the mass ratio of the 4-hydroxy-2-butanone oxime to the zinc is 1:1.

The yield of the aminobutanol obtained was 77.5% and the purity was 81.3%.

Example 15

This example differs from example 1 in that: the mass ratio of the 4-hydroxy-2-butanone oxime to the zinc is 1: 1.5.

The yield of the aminobutanol obtained was 84.5% and the purity was 96.2%.

Example 16

This example differs from example 1 in that: the mass ratio of the 4-hydroxy-2-butanone oxime to the zinc is 1: 2.5.

The yield of the aminobutanol obtained was 91.3% and the purity 98.2%.

Comparative example 1

This example differs from example 1 in that: in the reaction process of the butyl ketone alcohol and the hydroxylamine hydrochloride, NaOH is prepared from NaHCO₃Instead.

The yield of the aminobutanol obtained was 78.5% and the purity was 97.9%.

Comparative example 2

This example differs from example 1 in that: 4-hydroxy-2-butanone oxime and ammonium acetate are reacted under reflux in the presence of magnesium as catalyst.

The yield of the aminobutanol obtained was 67.4% and the purity was 75.8%.

In summary, the synthesis method of aminobutanol provided by the application adopts the butyl ketol as the starting material, and the cost is low. The method has the advantages of no use of Raney nickel and use of zinc as a catalyst in the synthesis process, low cost, high yield, no need of performing the reaction in an oxygen-free environment and under high pressure, mild reaction conditions, simple storage and subsequent treatment of the catalyst, good economic benefit and suitability for industrial production.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The method for synthesizing the aminobutanol is characterized by comprising the following steps of: heating 4-hydroxy-2-butanone oxime and formic acid or acetic acid to react in the presence of a catalyst;

the catalyst is zinc.

2. The synthesis method according to claim 1, wherein the mass ratio of the catalyst to the 4-hydroxy-2-butanone oxime is 1-2.5: 1;

preferably, the mass ratio of the catalyst to the 4-hydroxy-2-butanone oxime is 2-2.5: 1;

preferably, the dosage ratio of the 4-hydroxy-2-butanone oxime to the formic acid or the acetic acid is 100 g: 1.5-2.5L, wherein the formic acid or the acetic acid is respectively provided in the form of a formic acid solution or an acetic acid solution, and the volume concentration of the formic acid solution or the acetic acid solution is 45-55%.

3. The synthesis method according to claim 1, characterized in that the heating reaction is carried out at a temperature of 110-120 ℃ for 4-9 h;

preferably, heating to reflux.

4. The synthesis method according to claim 1, characterized by further comprising a step of removing zinc after the reaction is finished;

preferably, the dezincification is carried out by introducing H₂The method of S is carried out.

5. The synthesis method according to claim 1, wherein zinc is removed, solid-liquid separation is performed, and the solvent in the separated liquid is removed, followed by first extraction;

preferably, the pH is adjusted to not less than 11 before the first extraction is carried out;

preferably, the extractant of the first extraction comprises at least one of ethyl acetate, dichloromethane and diethyl ether;

preferably, the number of times of the first extraction is 1-3, and when the number of times is 3, the amount of the extractant used in each time is 150-180 mL;

preferably, after the first extraction, drying the ester layer after the first extraction is further included;

preferably, the drying agent used for drying comprises anhydrous sodium sulfate or anhydrous magnesium sulfate.

6. The synthesis method according to any one of claims 1 to 5, wherein the 4-hydroxy-2-butanone oxime is prepared by:

7. The method of claim 6, wherein the base used in the reaction of said butanonol with said hydroxylamine comprises NaOH and Na₂CO₃At least one of;

preferably, the base is NaOH;

preferably, when the alkali used for reacting the butanol with the hydroxylamine is NaOH, the concentration of the NaOH is 2-5 mol/L;

preferably, the concentration of the NaOH is 4-5 mol/L;

preferably, the dosage ratio of the butyl ketol to the base is 130 g: 500-600 mL.

8. The method of synthesizing according to claim 7, wherein the hydroxylamine comprises at least one of hydroxylamine hydrochloride, hydroxylamine phosphate and hydroxylamine sulfate;

preferably, the hydroxylamine is hydroxylamine hydrochloride;

preferably, when the hydroxylamine is hydroxylamine hydrochloride, the molar ratio of the butanol to the hydroxylamine hydrochloride is 1: 1-1.3;

preferably, the molar ratio of the butyl ketol to the hydroxylamine hydrochloride is 1: 1.2-1.3.

9. The synthesis method according to claim 8, wherein the butanonol reacts with the hydroxylamine at 55-65 ℃ for 25-35 min;

preferably, the reaction of the butanonol with the hydroxylamine is carried out under stirring conditions;

preferably, the reaction with the inorganic acid is carried out after the temperature is reduced to 25-30 ℃;

preferably, the inorganic acid includes at least one of hydrochloric acid, sulfuric acid, and phosphoric acid;

preferably, when the inorganic acid is hydrochloric acid, the dosage ratio of the hydrochloric acid to the butanol is 420-460 mL: 130g, and the concentration of the hydrochloric acid is 4.5-5.5 mol/L.

10. The method of synthesis of claim 6, wherein the second extractive extractant comprises at least one of ethyl acetate, dichloromethane, and diethyl ether;

preferably, the number of times of the second extraction is 1-3, and when the number of times is 3, the dosage of the extractant used in each time is 180-220 mL;

preferably, the solvent in the extract is removed by concentrating the extract at 35-40 deg.C to dryness.