阅读说明：本技术 β,β-亚氨基二丙腈的回收利用方法和应用 (Method for recycling beta, beta-iminodipropionitrile and application ) 是由 徐晓海 李褦成 陈英明 严建斌 于 2020-12-31 设计创作，主要内容包括：本发明提供了一种β,β-亚氨基二丙腈的回收利用方法和应用,涉及废物回收利用技术领域。该β,β-亚氨基二丙腈的回收利用方法,通过采用特定的反应合成路线,使得β,β-亚氨基二丙腈最终生成具有广泛用途的泛酸钙,上述回收利用方法,既减少危废排放与处理,降低危废处理成本,同时实现了β,β-亚氨基二丙腈变废为宝的目的,大大提高了β,β-亚氨基二丙腈的利用价值。本发明还提供了上述β,β-亚氨基二丙腈的回收利用方法的应用,鉴于上述β,β-亚氨基二丙腈的回收利用方法所具有的优势,使得其为制备泛酸钙提供了新的工艺路线。(The invention provides a method for recycling beta, beta-iminodipropionitrile and application thereof, relating to the technical field of waste recycling. The method for recycling the beta, beta-iminodiacetonitrile enables the beta, beta-iminodiacetonitrile to finally generate calcium pantothenate with wide application by adopting a specific reaction synthesis route. The invention also provides the application of the method for recycling the beta, beta-imino-dipropionitrile, and the method provides a new process route for preparing calcium pantothenate in view of the advantages of the method for recycling the beta, beta-imino-dipropionitrile.)

1. A method for recycling beta, beta-iminodipropionitrile, which is characterized by comprising the following steps:

(a) mixing beta, beta-iminodipropionitrile with ammonia water to carry out ammoniation reaction to obtain aminopropionitrile crude product;

(b) mixing the aminopropionitrile crude product with an alkaline hydroxide to perform hydrolysis reaction to obtain a aminopropionate solution;

(c) mixing the aminopropionic acid salt solution with acid, and then adding methanol to obtain aminopropionic acid methanol solution and alkali metal salt;

(d) mixing the aminopropionic acid methanol solution with calcium oxide for calcification reaction to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with pantoic acid lactone, and carrying out condensation reaction to obtain calcium pantothenate.

2. The recycling method according to claim 1, wherein in the step (a), the molar ratio of β, β -iminodipropionitrile to aqueous ammonia is 1: (10-15);

preferably, in the step (a), the temperature of the amination reaction is 110-;

preferably, in step (a), β, β -iminodipropionitrile is reacted with aqueous ammonia in a microchannel reactor.

3. The recycling method according to claim 2, wherein in the step (a), a catalyst is further added during the reaction, and the catalyst comprises isopropanol;

preferably, in step (a), the catalyst is used in an amount of 10 to 15% by mass based on the mass of β, β -iminodiacetonitrile.

4. The recycling method according to claim 1, wherein in the step (b), the alkali hydroxide comprises any one or a combination of at least two of sodium hydroxide, potassium hydroxide or calcium hydroxide, preferably sodium hydroxide;

preferably, the mass ratio of the alkaline hydroxide to the beta, beta-iminodipropionitrile is (1.75-1.88): 1;

preferably, in step (b), the temperature of the hydrolysis reaction is 95-110 ℃, and the hydrolysis reaction time is 1-3 h.

5. The recycling method according to claim 4, wherein in the step (b), the aminopropionitrile crude product is mixed with the alkaline hydroxide after ammonia water is recovered;

preferably, in the step (b), the temperature for recovering the ammonia water is 45-55 ℃, and the pressure is-0.08 to-0.09 MPa.

6. The recycling method according to claim 1, wherein in the step (c), the mixing temperature is 50-55 ℃ and the mixing time is 0.5-1.0 h;

preferably, in step (c), the acid comprises concentrated sulfuric acid or hydrochloric acid;

preferably, in step (c), the mass ratio of the acid to β, β -iminodipropionitrile is (0.70 to 0.75): 1;

preferably, in step (c), the mass ratio of methanol to β, β -iminodipropionitrile is (1.25 to 1.38): 1.

7. the recycling method according to claim 1, wherein in the step (d), the mass ratio of the calcium oxide to the β, β -iminodipropionitrile is (0.37-0.40): 1;

preferably, the temperature of the calcification reaction is 30-50 ℃, and the time of the calcification reaction is 4-6 h.

8. The recycling method according to claim 7, wherein in the step (d), the mass ratio of pantolactone to β, β -iminodipropionitrile is (2.7-3.1): 1;

preferably, the temperature of the condensation reaction is 0-10 ℃, and the time of the condensation reaction is 30-35 h.

9. The recycling method according to any one of claims 1 to 8, comprising the steps of:

(a) mixing beta, beta-iminodipropionitrile and ammonia water in a molar ratio of 1: (10-15) carrying out reaction in a microchannel reactor, wherein the reaction temperature is 110-135 ℃, and the pressure is 2.2-2.8MPa, so as to obtain a crude aminopropionitrile;

(b) after ammonia water is recovered from the aminopropionitrile crude product, mixing the aminopropionitrile crude product with alkaline hydroxide to perform hydrolysis reaction, wherein the temperature of the hydrolysis reaction is 95-110 ℃, and the time of the hydrolysis reaction is 1-3h to obtain aminopropionate solution;

(c) mixing the aminopropionic acid salt solution with concentrated sulfuric acid at 50-55 deg.C for 0.5-1.0h, and adding methanol to obtain aminopropionic acid methanol solution and sulfate;

(d) mixing the aminopropionic acid methanol solution with calcium oxide, and carrying out calcification reaction at 30-50 deg.C for 4-6 hr to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with pantoic acid lactone, and carrying out condensation reaction at 0-10 deg.C for 30-35 hr to obtain calcium pantothenate;

preferably, the conversion of the beta, beta-iminodipropionitrile is from 70 to 85%.

10. Use of the process for the recovery of β, β -iminodipropionitrile according to any one of claims 1 to 9 in the preparation of calcium pantothenate.

Technical Field

The invention relates to the technical field of waste recycling, in particular to a recycling method and application of beta, beta-iminodipropionitrile.

Background

In the process of synthesizing beta-aminopropionitrile from acrylonitrile, beta-iminodipropionitrile (short for aminopropionitrile high boiling point) is generated as a byproduct. At present, beta-iminodiacetonitrile can only be treated as dangerous waste, which increases the environmental protection treatment cost. Therefore, how to recycle the byproduct beta, beta-iminodipropionitrile, reduce the discharge and treatment of hazardous wastes, and reduce the treatment cost of the hazardous wastes is a problem to be solved in the field.

In view of the above, the present invention is particularly proposed to solve at least one of the above technical problems.

Disclosure of Invention

The first purpose of the invention is to provide a method for recycling beta, beta-iminodiacetonitrile, so as to solve the technical problem that the beta, beta-iminodiacetonitrile in the prior art can only be treated as hazardous waste and cannot be recycled.

The second object of the present invention is to provide an application of the above method for recovering and utilizing β, β -iminodipropionitrile.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a method for recycling beta, beta-iminodipropionitrile, which comprises the following steps:

(a) mixing beta, beta-iminodipropionitrile with ammonia water to carry out ammoniation reaction to obtain aminopropionitrile crude product;

(b) mixing the aminopropionitrile crude product with an alkaline hydroxide to perform hydrolysis reaction to obtain a aminopropionate solution;

(c) mixing the aminopropionic acid salt solution with acid, and then adding methanol to obtain aminopropionic acid methanol solution and alkali metal salt;

(d) mixing the aminopropionic acid methanol solution with calcium oxide for calcification reaction to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with pantoic acid lactone, and carrying out condensation reaction to obtain calcium pantothenate.

Further, on the basis of the above technical scheme of the present invention, in the step (a), the molar ratio of β, β -iminodipropionitrile to ammonia water is (1: 10): (1: 15);

preferably, in the step (a), the temperature of the amination reaction is 110-;

preferably, in step (a), β, β -iminodipropionitrile is reacted with aqueous ammonia in a microchannel reactor.

Further, on the basis of the above technical scheme of the present invention, in the step (a), a catalyst is further added during the reaction, wherein the catalyst comprises isopropanol;

preferably, in step (a), the catalyst is used in an amount of 10 to 15% by mass based on the mass of β, β -iminodiacetonitrile.

Further, on the basis of the above technical solution of the present invention, in the step (b), the alkaline hydroxide includes any one or a combination of at least two of sodium hydroxide, potassium hydroxide or calcium hydroxide, preferably sodium hydroxide;

preferably, the mass ratio of the alkaline hydroxide to the beta, beta-iminodipropionitrile is (1.75-1.88): 1;

preferably, in step (b), the temperature of the hydrolysis reaction is 95-110 ℃, and the hydrolysis reaction time is 1-3 h.

Further, on the basis of the technical scheme of the invention, in the step (b), the aminopropionitrile crude product is mixed with the alkaline hydroxide after ammonia water is recovered;

preferably, in the step (b), the temperature for recovering the ammonia water is 45-55 ℃, and the pressure is-0.08 to-0.09 MPa.

Further, on the basis of the technical scheme of the invention, in the step (c), the mixing temperature is 50-55 ℃, and the mixing time is 0.5-1.0 h;

preferably, in step (c), the acid comprises concentrated sulfuric acid or hydrochloric acid;

preferably, in step (c), the mass ratio of the acid to β, β -iminodipropionitrile is (0.70 to 0.75): 1;

preferably, in step (c), the mass ratio of methanol to β, β -iminodipropionitrile is (1.25 to 1.38): 1.

further, on the basis of the above technical solution of the present invention, in the step (d), the mass ratio of the calcium oxide to the β, β -iminodipropionitrile is (0.37-0.40): 1;

preferably, the temperature of the calcification reaction is 30-50 ℃, and the time of the calcification reaction is 4-6 h.

Further, on the basis of the above technical scheme of the present invention, in the step (d), the mass ratio of pantolactone to β, β -iminodipropionitrile is (2.7-3.1): 1;

preferably, the temperature of the condensation reaction is 0-10 ℃, and the time of the condensation reaction is 30-35 h.

Further, on the basis of the technical scheme of the invention, the method for recycling the beta, beta-iminodiacetonitrile comprises the following steps:

(a) mixing beta, beta-iminodipropionitrile and ammonia water in a molar ratio of 1: (10-15) carrying out reaction in a microchannel reactor, wherein the reaction temperature is 110-135 ℃, and the pressure is 2.2-2.8MPa, so as to obtain a crude aminopropionitrile;

(b) after ammonia water is recovered from the aminopropionitrile crude product, mixing the aminopropionitrile crude product with alkaline hydroxide to perform hydrolysis reaction, wherein the temperature of the hydrolysis reaction is 95-110 ℃, and the time of the hydrolysis reaction is 1-3h to obtain aminopropionate solution;

(c) mixing the aminopropionic acid salt solution with concentrated sulfuric acid at 50-55 deg.C for 0.5-1.0h, and adding methanol to obtain aminopropionic acid methanol solution and sulfate;

(d) mixing the aminopropionic acid methanol solution with calcium oxide, and carrying out calcification reaction at 30-50 deg.C for 4-6 hr to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with pantoic acid lactone, and carrying out condensation reaction at 0-10 deg.C for 30-35 hr to obtain calcium pantothenate;

preferably, the conversion of the beta, beta-iminodipropionitrile is from 70 to 85%.

The invention also provides the application of the recovery and utilization method of the beta, beta-iminodipropionitrile in the preparation of calcium pantothenate.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a method for recycling beta, beta-iminodiacetonitrile, which is characterized in that beta, beta-iminodiacetonitrile finally generates calcium pantothenate with wide application by adopting a specific reaction synthesis route.

(2) The invention provides the application of the method for recycling the beta, beta-iminodipropionitrile, and provides a new process route for preparing calcium pantothenate in view of the advantages of the method for recycling the beta, beta-iminodipropionitrile.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a process flow diagram of one embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. 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.

According to a first aspect of the present invention, there is provided a process for the recovery and utilization of β, β -iminodipropionitrile, comprising the steps of:

(a) mixing beta, beta-iminodipropionitrile with ammonia water to carry out ammoniation reaction to obtain aminopropionitrile crude product;

(b) mixing the aminopropionitrile crude product with an alkaline hydroxide to perform hydrolysis reaction to obtain a aminopropionate solution;

(c) mixing the aminopropionic acid salt solution with acid, and then adding methanol to obtain aminopropionic acid methanol solution and alkali metal salt;

(d) mixing the aminopropionic acid methanol solution with calcium oxide for calcification reaction to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with pantoic acid lactone, and carrying out condensation reaction to obtain calcium pantothenate.

Specifically, in the step (a), beta-iminodipropionitrile and ammonia water are subjected to ammoniation reaction to generate aminopropionitrile crude product, wherein the related reaction formula is as follows:

CNCH₂CH₂NHCH₂CH₂CN+NH₃·H₂O→2NH₂CH₂CH₂CN+H₂O

in the step (b), the aminopropionitrile crude product is subjected to hydrolysis reaction under the action of alkaline hydroxide (MOH) to obtain a aminopropionate solution, wherein the reaction formula is as follows:

NH₂CH₂CH₂CN+MOH+H₂O→NH₂CH₂CH₂COOM+NH₃

in order to ensure sufficient conversion of the crude aminopropionitrile into the aminopropionate solution, the addition of the basic hydroxide in step (b) is often excessive, so that the basic hydroxide remains in the aminopropionate solution formed. In order to neutralize the residual alkaline hydroxide and simultaneously convert the aminopropionate in the aminopropionate solution into aminopropionic acid, an acid is added in step (c) to form the corresponding alkali metal salt. After the neutralization with acid, methanol is added to form a methanol aminopropionate solution, and the alkali metal salt in the system can be completely discharged without residue. And the discharged alkali metal salt may be sold.

In the step (d), the aminopropionic acid methanol solution is mixed with calcium oxide, namely, aminopropionic acid and calcium oxide are subjected to calcification reaction in methanol to generate calcium aminopropionate, and then the calcium aminopropionate and pantolactone are subjected to polycondensation reaction to obtain calcium pantothenate.

Calcium pantothenate is an organic substance having the chemical formulaIs C₁₈H₃₂O₁₀N₂Ca is mainly used in the fields of medicines, foods, feed additives and the like.

The method for recycling the beta, beta-iminodiacetonitrile enables the beta, beta-iminodiacetonitrile to finally generate calcium pantothenate with wide application by adopting a specific reaction synthesis route.

As an alternative embodiment of the present invention, in step (a), the molar ratio of β, β -iminodipropionitrile to aqueous ammonia is 1: (10-15); typical but non-limiting molar ratios are 1: 10. 1: 11. 1: 12. 1: 13. 1: 14 or 1: 15.

as an alternative embodiment of the present invention, in step (a), the temperature of the amination reaction is 110 ℃ and 135 ℃, and the pressure of the amination reaction is 2.2-2.8 MPa. Typical but non-limiting amination temperatures are 110 ℃, 112 ℃, 115 ℃, 118 ℃, 120 ℃, 122 ℃, 125 ℃, 128 ℃, 130 ℃, 132 ℃, 134 ℃ or 135 ℃; typical but non-limiting ammonification reactions are at pressures of 2.2MPa, 2.4MPa, 2.5MPa, 2.6MPa, 2.7MPa or 2.8 MPa.

As an alternative embodiment of the present invention, in step (a), β, β -iminodipropionitrile is reacted with aqueous ammonia in a microchannel reactor.

In the prior art, beta-iminodipropionitrile and ammonia water generally adopt autoclave type reactors for reaction, the reactors provide intermittent reaction, and the mass transfer and heat transfer effects are poor, side reactions are more, and the product yield is low. The microchannel reactor is a novel reactor, provides continuous reaction, has good mass transfer effect and few side reactions, and can effectively improve the product yield.

The structure and the number of the microchannel reactor are not particularly limited.

In an alternative embodiment of the present invention, in step (a), a catalyst is further added during the reaction, wherein the catalyst comprises isopropanol. The catalyst isopropanol is added, so that the reaction yield can be effectively improved.

In an alternative embodiment of the present invention, in step (a), the catalyst is present in an amount of 10 to 15% by mass based on the mass of β, β -iminodipropionitrile. The catalyst is typically, but not limited to, 10%, 11%, 12%, 13%, 14% or 15% by mass of beta, beta-iminodipropionitrile.

The reaction yield can be further improved by limiting the specific type and the using amount of the catalyst.

As an alternative embodiment of the present invention, in the step (b), the alkaline hydroxide includes any one or a combination of at least two of sodium hydroxide, potassium hydroxide or calcium hydroxide, preferably sodium hydroxide.

In an alternative embodiment of the present invention, the mass ratio of the alkaline hydroxide to the β, β -iminodipropionitrile is (1.75 to 1.88): 1; the typical but non-limiting mass ratio of alkaline hydroxide to β, β -iminodipropionitrile is 1.75: 1. 1.76: 1. 1.78: 1. 1.80: 1. 1.82: 1. 1.84: 1. 1.85: 1. 1.86: 1 or 1.88: 1.

as an alternative embodiment of the present invention, in the step (b), the temperature of the hydrolysis reaction is 95-110 ℃ and the time of the hydrolysis reaction is 1-3 h. Typical but non-limiting hydrolysis temperatures are 95 deg.C, 98 deg.C, 100 deg.C, 102 deg.C, 104 deg.C, 105 deg.C, 106 deg.C, 108 deg.C or 110 deg.C. Typical but non-limiting hydrolysis reaction times are 1h, 2h or 3 h.

Since an excess of aqueous ammonia is usually used in step (a) to react with β, β -iminodiacetonitrile, the crude aminopropionitrile obtained usually contains aminopropionitrile, β -iminodiacetonitrile and aqueous ammonia. Therefore, the ammonia water in the aminopropionitrile crude product can be recycled and then subjected to subsequent hydrolysis reaction.

As an alternative embodiment of the present invention, in step (b), the crude aminopropionitrile is mixed with the basic hydroxide after recovering ammonia.

As an alternative embodiment of the present invention, the temperature used for recovering ammonia in step (b) is 45-55 ℃ and the pressure is-0.08 to-0.09 MPa. Typical but non-limiting ammonia recovery temperatures are 45 deg.C, 46 deg.C, 48 deg.C, 50 deg.C, 52 deg.C, 54 deg.C or 55 deg.C, and typical but non-limiting pressures are-0.08 MPa, -0.085MPa or-0.09 MPa.

As an alternative embodiment of the present invention, in the step (c), the mixing temperature is 50-55 ℃, and the mixing time is 0.5-1.0 h; typical but non-limiting mixing temperatures are 50 deg.C, 51 deg.C, 52 deg.C, 53 deg.C, 54 deg.C or 55 deg.C. Typical but non-limiting mixing times are 0.5h, 0.6h, 0.7h, 0.8h or 1.0 h.

As an alternative embodiment of the present invention, in step (c), the acid comprises concentrated sulfuric acid or hydrochloric acid.

The acid species are limited, so that the alkali metal salt mainly exists in the form of sulfate or hydrochloride, and the subsequent salt separation is facilitated. Meanwhile, concentrated sulfuric acid is preferably adopted, and the concentrated sulfuric acid does not bring water to the reaction system, so that water does not need to be recovered basically in the follow-up process, and a large amount of energy consumption generated by water recovery is reduced.

In an alternative embodiment of the present invention, the mass ratio of acid to β, β -iminodipropionitrile in step (c) is (0.70 to 0.75): 1; the typical but non-limiting mass ratio of acid to β, β -iminodipropionitrile is 0.70: 1. 0.72: 1. 0.74: 1 or 0.75: 1.

in an alternative embodiment of the present invention, in step (c), the mass ratio of methanol to β, β -iminodipropionitrile is (1.25 to 1.38): 1; a typical but non-limiting mass ratio of methanol to β, β -iminodipropionitrile is 1.25: 1. 1.26: 1. 1.28: 1. 1.30: 1. 1.32: 1. 1.34: 1. 1.35: 1. 1.36: 1 or 1.38: 1.

in an alternative embodiment of the present invention, in the step (d), the mass ratio of calcium oxide to β, β -iminodipropionitrile is (0.37 to 0.40): 1; the typical but non-limiting mass ratio of calcium oxide to β, β -iminodipropionitrile is 0.37: 1. 0.38: 1. 0.39: 1 or 0.40: 1.

as an alternative embodiment of the invention, the temperature of the calcification reaction is 30-50 ℃, and the time of the calcification reaction is 4-6 h. Typical but non-limiting calcification reactions are carried out at 30 ℃, 32 ℃, 34 ℃, 35 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 45 ℃, 46 ℃, 48 ℃ or 50 ℃. Typical but non-limiting calcification reactions take 4h, 5h or 6 h.

As an alternative embodiment of the present invention, in step (d), the mass ratio of pantolactone to β, β -iminodipropionitrile is (2.7 to 3.1): 1; typical but not limiting mass ratio of pantolactone to β, β -iminodipropionitrile 2.7: 1. 2.8: 1. 2.9: 1. 3.0: 1 or 3.1: 1.

as an alternative embodiment of the invention, the temperature of the condensation reaction is 0-10 ℃ and the time of the condensation reaction is 30-35 h. Typical but non-limiting condensation temperatures are 0 deg.C, 2 deg.C, 4 deg.C, 5 deg.C, 6 deg.C, 8 deg.C or 10 deg.C. Typical, but not limiting, condensation reactions take 30h, 31h, 32h, 33h, 34h or 35 h.

As a preferred embodiment of the present invention, the method for recycling β, β -iminodipropionitrile includes the following steps, and the specific process flow is shown in fig. 1:

(a) reacting beta, beta-iminodipropionitrile (high boiling) with ammonia water in a molar ratio of 1: (10-15) carrying out an ammoniation reaction in the microchannel reactor, wherein the temperature of the ammoniation reaction is 110-135 ℃, and the pressure is 2.2-2.8MPa, so as to obtain a crude aminopropionitrile;

(b) recovering ammonia water from the aminopropionitrile crude product, and mixing with 32% liquid caustic soda to perform hydrolysis reaction at 95-110 deg.C for 1-3h to obtain aminopropionate solution;

(c) mixing (neutralizing) a solution of aminopropionic acid salt with concentrated sulfuric acid at 50-55 ℃ for 0.5-1.0h, adding methanol, and discharging salt to obtain a solution of aminopropionic acid methanol and sodium sulfate;

(d) mixing the aminopropionic acid methanol solution with calcium oxide, and carrying out calcification reaction at 30-50 deg.C for 4-6 hr to obtain aminopropionic acid calcium;

mixing calcium aminopropionate with L-pantoic acid lactone, carrying out condensation reaction at 0-10 deg.C for 30-35 hr, and drying to obtain calcium pantothenate product.

Through further limiting the steps and process parameters of the method for recycling the beta, beta-iminodipropionitrile, the conversion rate of the beta, beta-iminodipropionitrile to the aminopropionitrile is optimal, the aim of turning waste into wealth is fulfilled, and high economic value is generated.

As an alternative embodiment of the invention, the conversion of β, β -iminodipropionitrile is in the range of from 70 to 85%. Typical, but not limiting, conversions of β, β -iminodipropionitrile are 70%, 72%, 74%, 75%, 76%, 78%, 80%, 82%, 84%, or 85%.

According to a second aspect of the present invention, there is also provided the use of the above-mentioned process for the recovery of β, β -iminodipropionitrile in the preparation of calcium pantothenate.

In view of the advantages of the beta, beta-iminodipropionitrile recycling method, a new process route is provided for preparing calcium pantothenate.

The present invention will be further described with reference to specific examples and comparative examples.

Example 1

The embodiment provides a method for recycling beta, beta-iminodipropionitrile, which comprises the following steps:

(a) quantitatively introducing 200g of beta, beta-iminodipropionitrile and 800g of 35% ammonia water (the molar ratio of the beta, beta-iminodipropionitrile to the ammonia water is 1:10) into a microchannel reactor for continuous ammoniation reaction at the reaction temperature of 110 ℃ and the pressure of 2.2MPa to obtain a crude aminopropionitrile product;

(b) the amino propionitrile crude product is mixed with 350g of 32% liquid caustic soda after ammonia water is recovered by minus 0.09Mpa negative pressure water bath at 50 ℃, and hydrolysis reaction is carried out at 105 ℃ for 2h to obtain amino propionic acid sodium salt solution;

(c) supplementing 140g of concentrated sulfuric acid into the aminopropionic acid sodium salt solution, neutralizing at 55 ℃, adding 250g of methanol after the neutralization is finished for about half an hour, and carrying out alcohol precipitation to discharge sodium sulfate to obtain aminopropionic acid methanol solution;

(d) adding 75g of calcium oxide into the aminopropionic acid methanol solution, and carrying out calcification reaction at 35 ℃ for 5h to obtain calcium aminopropionate;

mixing calcium aminopropionate with 360g of L-pantolactone to perform condensation reaction at 5 ℃ for 32 hours, and drying to obtain calcium pantothenate.

Example 2

This example provides a method for recycling β, β -iminodipropionitrile, which is the same as example 1 except that the reaction temperature in step (a) is 120 ℃.

Example 3

This example provides a method for recycling β, β -iminodipropionitrile, the steps and process parameters being the same as in example 1 except that the reaction temperature in step (a) is 130 ℃.

Example 4

This example provides a method for recycling β, β -iminodipropionitrile, the steps and process parameters being the same as in example 1 except that the reaction temperature in step (a) is 100 ℃.

Example 5

This example provides a method for recycling β, β -iminodipropionitrile, the steps and process parameters being the same as in example 1 except that the reaction temperature in step (a) is 135 ℃.

Example 6

This example provides a method for recycling β, β -iminodipropionitrile, the steps and process parameters being the same as in example 1 except that the reaction temperature in step (a) is 140 ℃.

Example 7

This example provides a method for recycling β, β -iminodipropionitrile, except that in step (a), the amount of 35% strength ammonia water was replaced with 1000g, i.e., the molar ratio of β, β -iminodipropionitrile to ammonia water was 1: 12.5, the rest of the steps and the process parameters are the same as in example 3.

Example 8

This example provides a method for recycling β, β -iminodipropionitrile, except that in step (a), the amount of 35% strength ammonia water was replaced with 1100g, i.e., the molar ratio of β, β -iminodipropionitrile to ammonia water was 1: 14, the remaining steps and process parameters were the same as in example 3.

Example 9

This example provides a method for recycling β, β -iminodipropionitrile, except that in step (a), the amount of 35% strength ammonia water was replaced with 1200g, i.e., the molar ratio of β, β -iminodipropionitrile to ammonia water was 1:15, the remaining steps and process parameters were the same as in example 3.

Example 10

This example provides a method for recycling β, β -iminodipropionitrile, except that in step (a), 720g of 35% strength ammonia water was used instead, i.e., the molar ratio of β, β -iminodipropionitrile to ammonia water was 1: 9, the rest of the steps and the process parameters were the same as in example 3.

Example 11

This example provides a method for recycling β, β -iminodipropionitrile, except that in step (a), the amount of 35% ammonia water was replaced with 1280g, i.e., the molar ratio of β, β -iminodipropionitrile to ammonia water was 1: 16, the remaining steps and process parameters were the same as in example 3.

Example 12

This example provides a method for recycling β, β -iminodipropionitrile, which is the same as example 1 except that 75g of isopropanol is added as a catalyst during the amination reaction in step (a), and the remaining steps and process parameters are the same as those in example 1.

Example 13

The embodiment provides a method for recycling beta, beta-iminodipropionitrile, which comprises the following steps:

(a) quantitatively introducing 200g of beta, beta-iminodipropionitrile and 800g of 35% ammonia water (the molar ratio of the beta, beta-iminodipropionitrile to the ammonia water is 1:10) into a microchannel reactor for continuous ammoniation reaction at the reaction temperature of 115 ℃ and the pressure of 2.3MPa to obtain a crude aminopropionitrile;

(b) the amino propionitrile crude product is mixed with 300g of 53 percent potassium hydroxide after ammonia water is recovered in negative pressure water bath with-0.09 Mpa at 50 ℃, and hydrolysis reaction is carried out at 105 ℃ for 2h to obtain amino potassium propionate solution;

(c) supplementing 140g of concentrated sulfuric acid into the aminopropionic acid potassium salt solution, neutralizing at 55 ℃, adding 250g of methanol after the neutralization is finished for about half an hour, and carrying out alcohol precipitation to discharge potassium sulfate to obtain aminopropionic acid methanol solution;

(d) adding 75g of calcium oxide into the aminopropionic acid methanol solution, and carrying out calcification reaction at 35 ℃ for 5h to obtain calcium aminopropionate;

mixing calcium aminopropionate with 360g of L-pantolactone to perform condensation reaction at 5 ℃ for 32 hours, and drying to obtain calcium pantothenate.

Example 14

This comparative example provides a process for the recovery of β, β -iminodipropionitrile except that concentrated sulfuric acid was replaced with 37% concentrated hydrochloric acid in step (c) and the remaining steps and process parameters were the same as in example 1.

To verify the technical effects of the examples, the following experiments were carried out.

Experimental example 1

Statistics were made on the quality of calcium pantothenate and the conversion rate of β, β -iminodiacetonitrile obtained by the method for recycling β, β -iminodiacetonitrile provided in examples 1 to 14, and the specific results are shown in table 1.

TABLE 1

As can be seen from the data in Table 1, the method for recycling the beta, beta-iminodipropionitrile provided by the invention realizes the process conversion of the beta, beta-iminodipropionitrile to calcium pantothenate, and achieves a high conversion rate of more than 70%.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.