Process for synthesizing and co-producing alpha-(o-chloroaniline)-based methenyl-beta-formylaminopropionitrile by using chlorine ester and application of process
By using acoustics as a acid bonding agent in synthetic α-chlorine-α-acetyl-γ-butthite lactone processes, and use by-products through hypenine contraction reactions, solving the large chlorine gas consumption in the existing process The problem of high treatment costs achieves the effect of reducing chlorine consumption and liquid alkali consumption, which significantly reduces production costs.
Patent Information
- Application Number
- CN202411727509.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-01-24
AI Technical Summary
The existing synthetic α-chloro-α-acetyl-γ-butyrolactone process has large chlorine consumption and high exhaust gas treatment costs, resulting in waste of chlorine and liquid alkali.
The use of acinideine as a acid-binding agent can generate α-chloro-alternate-α-acetyl-γ-butthobarne hydrochloride by reacting with the alpha-acetyl-γ-butthite reactions, and through the oleneramine, and The contraction reaction further uses by -products to reduce liquid and alkali consumption of chlorine consumption and tail gas treatment.
It effectively reduces the consumption of chlorine gas and liquid alkali for tail gas treatment, reduces the discharge of chlorine ester stratified water, and reduces production costs.
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Figure CN119350184A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of α-chloro-α-acetyl-γ-butyrolactone production, and in particular to a process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile and an application thereof. Background Art
[0002] α-Acetyl-γ-butyrolactone will generate hydrogen chloride and α-chloro-α-acetyl-γ-butyrolactone during the chlorine-passing reaction. Since the generated hydrogen chloride will undergo further hydrolysis and acidolysis with α-chloro-α-acetyl-γ-butyrolactone (chloroester), which will lead to a decrease in the content and yield of the chloroester, an acid-binding agent must be added during the synthesis of α-chloro-α-acetyl-γ-butyrolactone to absorb the hydrogen chloride generated by the reaction of chlorine and α-acetyl-γ-butyrolactone in a timely manner, thereby avoiding the problem of a decrease in the content and yield of the chloroester due to a side reaction between hydrogen chloride and the chloroester.
[0003] In the above reaction process, solid sodium bicarbonate is usually used as an acid binding agent, which not only causes a large amount of carbon dioxide to be generated during the reaction, but also part of the chlorine will be carried by the carbon dioxide during the chlorine passing process, resulting in an increase in chlorine consumption. At the same time, the tail gas generated needs to be washed and absorbed by the tail gas alkali washing tower before being discharged into the atmosphere, which causes a large amount of chlorine waste and liquid alkali waste in tail gas treatment, and also produces a large amount of wastewater that needs to be treated, which increases the treatment cost and the process production cost.
[0004] In view of this, the present invention is proposed. Summary of the invention
[0005] One of the purposes of the present invention is to provide a process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, which can solve the technical problems of large chlorine consumption and high tail gas treatment cost in the existing process for synthesizing α-chloro-α-acetyl-γ-butyrolactone.
[0006] The second object of the present invention is to provide an application of a process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, which is not only beneficial to avoiding waste of chlorine gas and waste of liquid caustic soda in tail gas treatment, but also can effectively utilize by-product hydrogen chloride, and is also beneficial to reducing the discharge of chloroester stratified water, thereby greatly reducing production costs.
[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:
[0008] In the first aspect, a process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile comprises the following steps:
[0009] In the process of introducing chlorine into an α-acetyl-γ-butyrolactone aqueous solution for reaction, o-chloroaniline is used as an acid binding agent to obtain α-chloro-α-acetyl-γ-butyrolactone and o-chloroaniline hydrochloride;
[0010] The o-chloroaniline hydrochloride is subjected to an enamine condensation reaction with α-sodium formyl-β-formylamino propionitrile to obtain α-(o-chloroaniline)methyl-β-formylamino propionitrile.
[0011] Furthermore, the temperature for introducing chlorine gas to react is 8°C-10°C.
[0012] Furthermore, the mass ratio of the α-acetyl-γ-butyrolactone to the chlorine gas is 192:110.
[0013] Furthermore, the mass ratio of the α-acetyl-γ-butyrolactone to o-chloroaniline is 1:1.
[0014] Furthermore, after the chlorine gas is introduced to react, the process also includes a step of allowing the obtained material to stand for stratification.
[0015] Furthermore, the temperature of the enamine condensation reaction is 20°C-30°C.
[0016] Furthermore, the enamine condensation reaction time is more than 12 hours.
[0017] Furthermore, after the enamine condensation reaction, the method further comprises a step of filtering the obtained product.
[0018] Furthermore, the filtering method includes centrifugation.
[0019] A second aspect is an application of the process described in any one of the above items in the production of vitamin B1.
[0020] Compared with the prior art, the present invention has at least the following beneficial effects:
[0021] The invention provides a process for synthesizing chloroester and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile. Since o-chloroaniline is used as an acid-binding agent to replace sodium bicarbonate in the original process, α-chloro-α-acetyl-γ-butyrolactone (chloroester) and o-chloroaniline hydrochloride are generated by reaction. After the reaction system is allowed to stand for stratification, the obtained α-chloro-α-acetyl-γ-butyrolactone can be used for the synthesis of vitamin B1. Meanwhile, the stratified water obtained by stratification can be directly used for the synthesis of α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (enamine) because o-chloroaniline hydrochloride is dissolved therein. The α-chloro-α-acetyl-γ-butyrolactone can also be used for the synthesis of vitamin B1. In summary, compared with the existing chloroester synthesis process, the co-production process of the present invention adopts o-chloroaniline as an acid-binding agent, which not only reduces the consumption of sodium bicarbonate, but also avoids the output of a large amount of carbon dioxide, avoids the escape of chlorine carried by carbon dioxide, effectively reduces the consumption of chlorine, and also reduces the consumption of liquid alkali for tail gas treatment, and also achieves the purpose of effectively utilizing the by-product hydrogen chloride and reducing the discharge of chloroester stratified water.
[0022] The application of the process for synthesizing chloroester and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile provided by the present invention is not only conducive to avoiding the waste of chlorine gas and the waste of liquid caustic soda in tail gas treatment, but also can effectively utilize the by-product hydrogen chloride, and is conducive to reducing the discharge of chloroester stratified water, thereby greatly reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0024] Figure 1 The schematic diagram of the reaction of synthesizing α-chloro-α-acetyl-γ-butyrolactone using sodium bicarbonate as an acid-binding agent in the prior art;
[0025] Figure 2 A reaction schematic diagram of a co-production process provided for one embodiment of the present invention. DETAILED DESCRIPTION
[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0027] In the existing process for synthesizing α-chloro-α-acetyl-γ-butyrolactone, sodium bicarbonate is used as an acid-binding agent. The reaction diagram is shown in Figure 1 The excess chlorine and a large amount of carbon dioxide produced need to be absorbed by the tail gas alkali washing tower and then discharged into the atmosphere, which causes a large amount of chlorine waste and liquid alkali waste in tail gas treatment, and a large amount of waste water needs to be treated, which leads to the production cost of the process not having an advantage. In view of this, the technical solution of the present invention is specially proposed.
[0028] According to a first aspect of the present invention, there is provided a process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, comprising the following steps:
[0029] In the process of introducing chlorine into an α-acetyl-γ-butyrolactone aqueous solution for reaction, o-chloroaniline is used as an acid binding agent to obtain α-chloro-α-acetyl-γ-butyrolactone and o-chloroaniline hydrochloride;
[0030] The o-chloroaniline hydrochloride is subjected to an enamine condensation reaction with α-sodium formyl-β-formylaminopropionitrile to obtain α-(o-chloroaniline)methyl-β-formylaminopropionitrile.
[0031] The process for synthesizing chloroester and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile provided by the present invention is shown in the reaction schematic diagram. Figure 2 Since o-chloroaniline is used as an acid-binding agent to replace sodium bicarbonate in the original process, α-chloro-α-acetyl-γ-butyrolactone (chloroester) and o-chloroaniline hydrochloride will be generated by reaction. After the reaction system is allowed to stand for stratification, the obtained α-chloro-α-acetyl-γ-butyrolactone can be used for the synthesis of vitamin B1. At the same time, the stratification water obtained by stratification can be directly used to synthesize α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (referred to as enamine) because o-chloroaniline hydrochloride is dissolved in the stratification water, which can also be used for the synthesis of vitamin B1.
[0032] In summary, compared with the existing chloroester synthesis process, the co-production process of the present invention adopts o-chloroaniline as an acid-binding agent, which not only reduces the consumption of sodium bicarbonate, but also avoids the output of a large amount of carbon dioxide, avoids the escape of chlorine carried by carbon dioxide, effectively reduces the consumption of chlorine, and also reduces the consumption of liquid alkali for tail gas treatment, and also achieves the purpose of effectively utilizing the by-product hydrogen chloride and reducing the discharge of chloroester stratified water.
[0033] In a preferred embodiment, the temperature for introducing chlorine gas for the reaction can be 8°C-10°C, and typical but non-limiting temperatures are, for example, 8°C, 9°C, and 10°C, which are more conducive to the full reaction of α-acetyl-γ-butyrolactone to synthesize α-chloro-α-acetyl-γ-butyrolactone and more conducive to improving the yield of chloroester.
[0034] In the present invention, the mass ratio of α-acetyl-γ-butyrolactone to chlorine can be 192:110, but is not limited thereto; the mass ratio of α-acetyl-γ-butyrolactone to o-chloroaniline can be 1:1, but is not limited thereto.
[0035] In a preferred embodiment, after the chlorine gas is introduced for reaction, the process further comprises the step of standing and stratifying the obtained material, after which the stratification is performed, to obtain a layered aqueous solution of α-chloro-α-acetyl-γ-butyrolactone and o-chloroaniline hydrochloride, to which the layered aqueous solution of o-chloroaniline hydrochloride is added α-sodium formyl-β-formylaminopropionitrile for enamine condensation reaction, thereby directly synthesizing α-(o-chloroaniline)methyl-β-formylaminopropionitrile.
[0036] In a preferred embodiment, the temperature of the enamine condensation reaction can be 20°C-30°C, and typical but non-limiting temperatures are, for example, 20°C, 22°C, 24°C, 26°C, 28°C, and 30°C. The time of the enamine condensation reaction can be more than 12 hours, which is more conducive to the full reaction of o-chloroaniline hydrochloride to synthesize α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, and is more conducive to improving the yield of enamine.
[0037] In the present invention, after the enamine condensation reaction, the step of filtering the obtained product is also included; wherein the filtering method includes but is not limited to centrifugation. The obtained product α-(o-chloroaniline)methyl-β-formylaminopropionitrile is filtered through a centrifuge, and the filter cake obtained by centrifugation is washed with water and then dried to obtain a dry enamine product.
[0038] According to a second aspect of the present invention, there is provided an application of any of the above-mentioned processes in the production of vitamin B1.
[0039] The application of the process for synthesizing chloroester and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile provided by the present invention is not only conducive to avoiding the waste of chlorine gas and the waste of liquid caustic soda in tail gas treatment, but also can effectively utilize the by-product hydrogen chloride, and is conducive to reducing the discharge of chloroester stratified water, thereby greatly reducing the production cost.
[0040] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.
[0041] Example 1
[0042] A process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, the process parameters and reaction results are shown in Table 1, comprising the following steps:
[0043] (1) Ingredients of chlorination kettle:
[0044] In the chlorination reaction kettle, 192 kg of α-acetyl-γ-butyrolactone, 192 kg of o-chloroaniline and 260 kg of purified water were added respectively, and the materials were mixed evenly;
[0045] (2) Cooling and chlorine circulation:
[0046] The jacket of the chlorination reaction kettle is passed with cooling water, the material temperature in the chlorination reaction kettle is controlled at 8°C-10°C, and 107 kg of chlorine gas is passed into the chlorination reaction kettle. The reaction cycle of passing chlorine gas is controlled to be about 5 hours-6 hours. After the chlorine gas is passed, the temperature is kept for 30 minutes;
[0047] (3) Vacuum chlorine removal:
[0048] Exhaust the excess chlorine in the chlorination reaction kettle with vacuum negative pressure;
[0049] (4) Standing stratification:
[0050] The materials in the chlorination reaction kettle were placed in a static layer to obtain 235 kg of α-chloro-α-acetyl-γ-butyrolactone (chloroester for short), with a detected content of 96.5% and a calculated yield of 93%;
[0051] The by-product o-chloroaniline hydrochloride aqueous solution (chloroester aqueous solution) obtained by standing and stratifying is applied to the enamine condensation kettle;
[0052] (5) Enamine condensation reactor ingredients:
[0053] In the enamine condensation kettle, add 500 kg of the chloroester layering water obtained in step (4), and continue to add 380 kg of tap water, and start stirring;
[0054] (6) Enamine condensation:
[0055] 260 kg (control the reaction temperature at 20° C.-30° C.) of α-sodium formyl-β-formylaminopropionitrile (hereinafter referred to as sodium formyl) (content 80%) is added to the reaction solution in the enamine condensation reactor in step (5) for 50 minutes. After the addition is completed, the temperature is kept at a constant temperature for more than 12 hours;
[0056] (7) Centrifugal filtration and drying of enamine:
[0057] After the insulation is completed, the α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (hereinafter referred to as enamine) obtained by the reaction is filtered using a centrifuge, and the filter cake obtained by centrifugation is washed with tap water, and then discharged to boiling and drying. After drying, 328 kg of dry enamine is obtained, and the enamine content is detected to be 96%, and the enamine synthesis yield is 95.13%.
[0058] Example 2
[0059] A process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, the process parameters and reaction results are shown in Table 1, comprising the following steps:
[0060] (1) Ingredients of chlorination kettle:
[0061] In the chlorination reaction kettle, 192 kg of α-acetyl-γ-butyrolactone, 192 kg of o-chloroaniline and 260 kg of purified water were added respectively, and the materials were mixed evenly;
[0062] (2) Cooling and chlorine circulation:
[0063] The jacket of the chlorination reaction kettle is passed with cooling water, the material temperature in the chlorination reaction kettle is controlled at 8°C-10°C, and 108 kg of chlorine gas is passed into the chlorination reaction kettle. The reaction cycle of passing chlorine gas is controlled to be about 5 hours-6 hours. After the chlorine gas is passed, the temperature is kept for 30 minutes;
[0064] (3) Vacuum chlorine removal:
[0065] Exhaust the excess chlorine in the chlorination reaction kettle with vacuum negative pressure;
[0066] (4) Standing stratification:
[0067] The materials in the chlorination reaction kettle were placed in a static layer to obtain 237 kg of α-chloro-α-acetyl-γ-butyrolactone (chloroester for short), with a detected content of 96.8% and a calculated yield of 94.2%;
[0068] The by-product o-chloroaniline hydrochloride aqueous solution (chloroester aqueous solution) obtained by standing and stratifying is applied to the enamine condensation kettle;
[0069] (5) Enamine condensation reactor ingredients:
[0070] In the enamine condensation kettle, add 500 kg of the chloroester layering water obtained in step (4), and continue to add 380 kg of tap water, and start stirring;
[0071] (6) Enamine condensation:
[0072] 260 kg (control the reaction temperature at 20° C.-30° C.) of α-sodium formyl-β-formylaminopropionitrile (hereinafter referred to as sodium formyl) (content 80%) is added to the reaction solution in the enamine condensation reactor in step (5) for 50 minutes. After the addition is completed, the temperature is kept at a constant temperature for more than 12 hours;
[0073] (7) Centrifugal filtration and drying of enamine:
[0074] After the insulation is completed, the α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (hereinafter referred to as enamine) obtained by the reaction is filtered using a centrifuge, and the filter cake obtained by centrifugation is washed with tap water, and then discharged to boiling and drying. After drying, 327.5 kg of dry enamine is obtained, and the enamine content is detected to be 96.2%, and the enamine synthesis yield is 95.18%.
[0075] Example 3
[0076] A process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, the process parameters and reaction results are shown in Table 1, comprising the following steps:
[0077] (1) Ingredients of chlorination kettle:
[0078] In the chlorination reaction kettle, 192 kg of α-acetyl-γ-butyrolactone, 192 kg of o-chloroaniline and 260 kg of purified water were added respectively, and the materials were mixed evenly;
[0079] (2) Cooling and chlorine circulation:
[0080] The jacket of the chlorination reaction kettle is passed with cooling water, the material temperature in the chlorination reaction kettle is controlled at 8°C-10°C, and 109 kg of chlorine gas is passed into the chlorination reaction kettle. The reaction cycle of passing chlorine gas is controlled to be about 5 hours-6 hours. After the chlorine gas is passed, the temperature is kept for 30 minutes;
[0081] (3) Vacuum chlorine removal:
[0082] Exhaust the excess chlorine in the chlorination reaction kettle with vacuum negative pressure;
[0083] (4) Standing stratification:
[0084] The materials in the chlorination reaction kettle were placed in a static layer to obtain 240 kg of α-chloro-α-acetyl-γ-butyrolactone (chloroester for short), with a detected content of 96.6% and a calculated yield of 95.17%;
[0085] The by-product o-chloroaniline hydrochloride aqueous solution (chloroester aqueous solution) obtained by standing and stratifying is applied to the enamine condensation kettle;
[0086] (5) Enamine condensation reactor ingredients:
[0087] In the enamine condensation kettle, add 500 kg of the chloroester layering water obtained in step (4), and continue to add 380 kg of tap water, and start stirring;
[0088] (6) Enamine condensation:
[0089] 260 kg (control the reaction temperature at 20° C.-30° C.) of α-sodium formyl-β-formylaminopropionitrile (hereinafter referred to as sodium formyl) (content 80%) is added to the reaction solution in the enamine condensation reactor in step (5) for 50 minutes. After the addition is completed, the temperature is kept at a constant temperature for more than 12 hours;
[0090] (7) Centrifugal filtration and drying of enamine:
[0091] After the insulation is completed, the α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (hereinafter referred to as enamine) obtained by the reaction is filtered using a centrifuge, and the filter cake obtained by centrifugation is washed with tap water, and then discharged to boiling and drying. After drying, 329 kg of dry enamine is obtained, and the enamine content is 95.8% and the enamine synthesis yield is 95.22%.
[0092] Example 4
[0093] A process for synthesizing chloroesters and co-producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, the process parameters and reaction results are shown in Table 1, comprising the following steps:
[0094] (1) Ingredients of chlorination kettle:
[0095] In the chlorination reaction kettle, 192 kg of α-acetyl-γ-butyrolactone, 192 kg of o-chloroaniline and 260 kg of purified water were added respectively, and the materials were mixed evenly;
[0096] (2) Cooling and chlorine circulation:
[0097] The jacket of the chlorination reaction kettle is passed with cooling water, the material temperature in the chlorination reaction kettle is controlled at 8°C-10°C, and 110 kg of chlorine gas is passed into the chlorination reaction kettle. The reaction cycle of passing chlorine gas is controlled to be about 5 hours-6 hours. After the chlorine gas is passed, the temperature is kept for 30 minutes;
[0098] (3) Vacuum chlorine removal:
[0099] Exhaust the excess chlorine in the chlorination reaction kettle with vacuum negative pressure;
[0100] (4) Standing stratification:
[0101] The material in the chlorination reaction kettle was placed and stratified to obtain 242 kg of α-chloro-α-acetyl-γ-butyrolactone (chloroester), with a detected content of 96.7% and a calculated yield of 96%;
[0102] The by-product o-chloroaniline hydrochloride aqueous solution (chloroester aqueous solution) obtained by standing and stratifying is applied to the enamine condensation kettle;
[0103] (5) Enamine condensation reactor ingredients:
[0104] In the enamine condensation kettle, add 500 kg of the chloroester layering water obtained in step (4), and continue to add 380 kg of tap water, and start stirring;
[0105] (6) Enamine condensation:
[0106] 260 kg (control the reaction temperature at 20° C.-30° C.) of α-sodium formyl-β-formylaminopropionitrile (hereinafter referred to as sodium formyl) (content 80%) is added to the reaction solution in the enamine condensation reactor in step (5) for 50 minutes. After the addition is completed, the temperature is kept at a constant temperature for more than 12 hours;
[0107] (7) Centrifugal filtration and drying of enamine:
[0108] After the insulation is completed, the α-(o-chloroaniline)-methyl-β-formylaminopropionitrile (hereinafter referred to as enamine) obtained by the reaction is filtered using a centrifuge, and the filter cake obtained by centrifugation is washed with tap water, and then discharged to boiling and drying. After drying, 328.2 kg of dry enamine is obtained, and the enamine content is detected to be 96.1%, and the enamine synthesis yield is 95.29%.
[0109] Comparative Example 1
[0110] A process for synthesizing chloroester, process parameters and reaction results are shown in Table 1, comprising the following steps:
[0111] (1) Ingredients of chlorination kettle:
[0112] In the chlorination reaction kettle, 192 kg of α-acetyl-γ-butyrolactone, 126 kg of sodium bicarbonate and 260 kg of purified water were added respectively, and the materials were mixed evenly;
[0113] (2) Cooling and chlorine circulation:
[0114] The jacket of the chlorination reaction kettle is passed with cooling water, the material temperature in the chlorination reaction kettle is controlled at 8°C-10°C, and 116 kg of chlorine gas is passed into the chlorination reaction kettle. The reaction cycle of passing chlorine gas is controlled to be about 5 hours-6 hours. After the chlorine gas is passed, the temperature is kept for 30 minutes;
[0115] The chlorination reactor is emptied and connected to the alkali washing tower for alkali washing to absorb the carbon dioxide produced by the reaction and the chlorine carried. After saturation, the concentrated wastewater is evaporated and the salt is discharged;
[0116] (3) Vacuum chlorine removal:
[0117] Exhaust the excess chlorine in the chlorination reaction kettle with vacuum negative pressure;
[0118] (4) Standing stratification:
[0119] The material in the chlorination reaction kettle was placed and stratified to obtain 239.6 kg of α-chloro-α-acetyl-γ-butyrolactone (chloroester), with a detected content of 96.5% and a calculated yield of 95.87%;
[0120] The chloroester layered water obtained by static stratification is subjected to concentrated wastewater triple-effect evaporation to remove salt.
[0121] Table 1
[0122]
[0123] As shown in Table 1, Comparative Example 1 is an existing synthetic α-chloro-α-acetyl-γ-butyrolactone process, and the chloroester obtained by its layering is 239.6kg, and a content of 96.5%, and a yield of 95.87%. The process needs to consume a large amount of sodium bicarbonate as an acid binding agent, and the carbon dioxide produced by the acid binding agent simultaneously carries chlorine out, resulting in a larger chlorine consumption; In the process of Example 1, o-chloroaniline is used as an acid binding agent, and the chlorine intake is 107kg. Compared with the process of Comparative Example 1, the process of Example 1 reduces chlorine The amount of chlorine used in the process of Example 2 is 9kg, and the chloroester obtained by layering is 235kg (content 96.5%, yield 93%), and the chloroester is subsequently used for layering and hydration to synthesize enamine, and the output enamine is 328kg (content 96%, yield 95.13%); the process of Example 2 uses o-chloroaniline as an acid binding agent, and the amount of chlorine introduced is 108kg. Compared with the process of Comparative Example 1, the process of Example 2 reduces the amount of chlorine used by 8kg, and the chloroester obtained by layering is 237kg (content 96.8%, yield 94.2%), and the subsequent chlorine is used The ester was hydrated to synthesize enamine, and the output of enamine was 327.5 kg (content 96.2%, yield 95.18%); the process of Example 3 used o-chloroaniline as an acid binding agent, and the amount of chlorine introduced was 109 kg. Compared with the process of Comparative Example 1, the process of Example 3 reduced the amount of chlorine by 7 kg, and the chloroester obtained by stratification was 240 kg (content 96.6%, yield 95.17%), and the chloroester was subsequently hydrated to synthesize enamine, and the output of enamine was 329 kg (content 95.8%, yield 95.22%); In the process of Example 4, o-chloroaniline is used as an acid binding agent, and the amount of chlorine introduced is 110 kg. Compared with the process of Comparative Example 1, the process of Example 4 reduces the amount of chlorine by 6 kg, and the chloroester obtained by layering is 242 kg (content 96.7%, yield 96%). It can be seen that the yield of chloroester has reached the normal yield level compared with Comparative Example 1, and the subsequent chloroester layering water synthesis enamine is applied to produce 328.2 kg (content 96.1%, yield 95.29%) of enamine, which shows that the content and yield of the co-production of enamine by the chloroester layering water are normal.
[0124] It can be seen that the present invention adopts o-chloroaniline to replace sodium bicarbonate as an acid binding agent, which can not only effectively reduce the sodium bicarbonate raw material consumption of the existing process, but also does not produce a large amount of carbon dioxide during the reaction process, which effectively avoids the escape of carbon dioxide carrying chlorine, effectively reduces the consumption of chlorine, and also reduces the consumption of liquid alkali for tail gas treatment; In addition, the by-product o-chloroaniline hydrochloride layered aqueous solution obtained by static stratification can be directly used to synthesize α-(o-chloroaniline)-methyl-β-formylamino propionitrile, which effectively comprehensively utilizes the by-product hydrogen chloride produced during the synthesis of α-chloro-α-acetyl-γ-butyrolactone, and also reduces the hydrochloric acid consumption during the synthesis of α-(o-chloroaniline)-methyl-β-formylamino propionitrile; In addition, since the o-chloroaniline hydrochloride layered aqueous solution after stratification directly synthesizes α-(o-chloroaniline)-methyl-β-formylamino propionitrile, the discharge of chloroester layered water in the existing process is effectively reduced, and the disposal cost of wastewater is effectively reduced. In short, under the above advantages, the co-production process of the present invention can greatly reduce production costs and effectively improve enterprise benefits.
[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A process for synthesizing chloroesters and producing α-(o-chloroaniline)-methyl-β-formylaminopropionitrile, characterized in that: The following steps are involved: In the process of introducing chlorine into an α-acetyl-γ-butyrolactone aqueous solution for reaction, o-chloroaniline is used as an acid binding agent to obtain α-chloro-α-acetyl-γ-butyrolactone and o-chloroaniline hydrochloride; The o-chloroaniline hydrochloride is subjected to an enamine condensation reaction with α-sodium formyl-β-formylamino propionitrile to obtain α-(o-chloroaniline)methyl-β-formylamino propionitrile.
2. The process according to claim 1, characterized in that The temperature for introducing chlorine gas to react is 8°C-10°C.
3. The process according to claim 2, characterized in that The mass ratio of the α-acetyl-γ-butyrolactone to the chlorine gas is 192:
110.
4. The process according to claim 3, characterized in that The mass ratio of the α-acetyl-γ-butyrolactone to o-chloroaniline is 1:
1.
5. The process according to any one of claims 1 to 4, characterized in that After the chlorine gas is introduced to react, the method further comprises the step of allowing the obtained material to stand for stratification.
6. The process according to claim 1, characterized in that The temperature of the enamine condensation reaction is 20°C-30°C.
7. The process according to claim 6, characterized in that The enamine condensation reaction time is more than 12 hours.
8. The process according to claim 7, characterized in that The method further comprises filtering the obtained product after the enamine condensation reaction.
9. The process according to claim 8, characterized in that The filtering method includes centrifugation.
10. Use of the process according to any one of claims 1 to 9 in the production of vitamin B1.