CN110975784A - Feeding device and feeding process of ethylene oxide in metronidazole hydroxylation reaction - Google Patents
Feeding device and feeding process of ethylene oxide in metronidazole hydroxylation reaction Download PDFInfo
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- CN110975784A CN110975784A CN201911049263.0A CN201911049263A CN110975784A CN 110975784 A CN110975784 A CN 110975784A CN 201911049263 A CN201911049263 A CN 201911049263A CN 110975784 A CN110975784 A CN 110975784A
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- ethylene oxide
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- hydroxylation
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- metronidazole
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
- B01J19/1868—Stationary reactors having moving elements inside resulting in a loop-type movement
- B01J19/1881—Stationary reactors having moving elements inside resulting in a loop-type movement externally, i.e. the mixture leaving the vessel and subsequently re-entering it
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J4/00—Feed or outlet devices; Feed or outlet control devices
- B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
- B01J4/002—Nozzle-type elements
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
- C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
- C07D233/66—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D233/91—Nitro radicals
- C07D233/92—Nitro radicals attached in position 4 or 5
- C07D233/94—Nitro radicals attached in position 4 or 5 with hydrocarbon radicals, substituted by oxygen or sulfur atoms, attached to other ring members
Abstract
The invention provides a feeding device and a feeding process of ethylene oxide in metronidazole hydroxylation reaction, wherein the feeding device comprises a hydroxylation reaction kettle and an external circulating pipeline positioned outside the hydroxylation reaction kettle, one end of the external circulating pipeline is connected with the bottom of the hydroxylation reaction kettle, the other end of the external circulating pipeline is connected with the top of the hydroxylation reaction kettle, a hydroxylation kettle bottom valve, an external circulating pump, a Venturi ejector, an ascending reaction pipeline and a first stop valve are sequentially arranged on the external circulating pipeline from the bottom of the hydroxylation reaction kettle to the top of the hydroxylation reaction kettle, an ethylene oxide introducing pipeline is arranged at the throat of the Venturi ejector, and an esterification kettle connecting pipeline is arranged between the ascending reaction pipeline and the first stop valve of the external circulating pipeline. The feeding device and the feeding process can reduce the ton consumption of ethylene oxide in metronidazole hydroxylation reaction to 0.9-1.0, thereby reducing the production cost of metronidazole and simultaneously reducing the discharge of ethylene oxide and the content of glycol in sewage.
Description
Technical Field
The invention belongs to the fields of organic synthesis and environmental protection and consumption reduction, and particularly relates to a feeding device and a feeding process for ethylene oxide in metronidazole hydroxylation reaction.
Background
Metronidazole is a nitroimidazole derivative, and is used for treating or preventing systemic or local infection caused by anaerobic bacteria, inhibiting oxidation-reduction reaction of amebic protozoa, breaking nitrogen chains of the amebic protozoa, producing metabolites which have anti-anaerobic bacteria effect when reduced in human bodies, and inhibiting synthesis of deoxyribonucleic acid of bacteria, thereby interfering growth and reproduction of the bacteria and finally causing death of the bacteria. Can be widely used for treating infection of abdominal cavity, digestive tract, female reproductive system, lower respiratory tract, skin and soft tissue, bone and joint. It also has therapeutic effects on septicemia, endocarditis, meningeal infection, and colitis caused by antibiotic.
The production process of metronidazole involves hydroxylation reaction of 2-methyl-5-nitroimidazole and ethylene oxide. The reaction equation is as follows:
the existing process is to dissolve 2-methyl-5 nitroimidazole in a mixed acid of formic acid and concentrated sulfuric acid, and to alternately introduce ethylene oxide and drop concentrated sulfuric acid at a certain temperature to perform hydroxylation reaction. Theoretically, the consumption per ton for producing 1 ton of metronidazole is 0.257, and the actual consumption per ton is as high as 1.2-1.3. The reasons for the high ton consumption of ethylene oxide are: firstly, because the boiling point of the ethylene oxide is 10.8 ℃ and the reaction temperature is about 90 ℃, the ethylene oxide enters the reaction kettle in a gaseous state and cannot be dissolved and reacted, and the ethylene oxide which is not dissolved and reacted escapes from the reaction liquid surface and is discharged into the atmosphere through the emptying pipe, thereby causing the waste of the ethylene oxide and the environmental problem; secondly, the ethylene oxide is distributed unevenly in the kettle, the concentration of the ethylene oxide at the introducing point is large, a part of the ethylene oxide reacts with the raw material 2-methyl-5 nitroimidazole at the introducing point, and the redundant ethylene oxide at the introducing point and water in formic acid generate ring-opening side reaction under the acidic condition to generate ethylene glycol. Not only the ethylene oxide is lost, but also the generated ethylene glycol is remained in the wastewater in the post-treatment process, which causes extremely high COD and is difficult to treat. Therefore, the ton consumption of the ethylene oxide is reduced, the cost can be saved, and the pressure of sewage treatment and atmospheric pollution can be reduced.
Aiming at the defects of the process of introducing the ethylene oxide in the production process, the invention provides a novel method for adding the ethylene oxide.
Disclosure of Invention
The invention aims to provide a feeding device and a feeding process for ethylene oxide in metronidazole hydroxylation reaction, which are used for solving the problems of uneven concentration distribution of ethylene oxide and easy overflow of gas to a liquid level in the hydroxylation reaction.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a feeding device for ethylene oxide in metronidazole hydroxylation reaction, which comprises a hydroxylation reaction kettle and an external circulating pipeline positioned outside the hydroxylation reaction kettle, wherein one end of the external circulating pipeline is connected with the bottom of the hydroxylation reaction kettle, the other end of the external circulating pipeline is connected with the top of the hydroxylation reaction kettle, a hydroxylation kettle bottom valve, an external circulating pump, a Venturi ejector, an ascending reaction pipeline (11) and a first stop valve are sequentially arranged on the external circulating pipeline from the bottom of the hydroxylation reaction kettle to the top of the hydroxylation reaction kettle, an ethylene oxide introducing pipeline is arranged at the throat of the Venturi ejector, and an esterification kettle connecting pipeline is arranged between the ascending reaction pipeline and the first stop valve of the external circulating pipeline.
Further, the ethylene oxide is stored in an ethylene oxide storage tank, and a third stop valve is arranged at an outlet of the ethylene oxide storage tank.
Further, the nitrogen is reserved in a nitrogen storage tank, and a fourth stop valve is arranged at an outlet of the nitrogen storage tank.
Further, the ascending reaction conduit has a pressure and a length suitable for the hydroxylation reaction.
The second aspect of the invention provides a feeding process of an ethylene oxide feeding device in metronidazole hydroxylation reaction, wherein the ethylene oxide is introduced into a throat of a Venturi ejector by using the feeding device of the ethylene oxide in the metronidazole hydroxylation reaction, and the ethylene oxide enters an external circulation pipeline, is fully mixed with a raw material liquid for reaction, flows through a section of ascending reaction pipeline, and then returns to a hydroxylation reaction kettle for circular reaction.
The feeding process of the feeding device adopting ethylene oxide in metronidazole hydroxylation reaction comprises the following steps:
step 1: adding raw materials into a hydroxylation reaction kettle, heating to a reaction temperature to enable the raw materials to be dissolved clearly to obtain a raw material solution; the raw materials are formic acid, sulfuric acid and 2-methyl-5-nitroimidazole;
step 2: starting an external circulating pump, and externally circulating the raw material liquid through an external circulating pipeline;
and step 3: introducing ethylene oxide at the throat of the Venturi ejector, wherein the ethylene oxide enters an external circulation pipeline, is fully mixed with the raw material liquid for reaction, flows through a rising reaction pipeline, returns to the hydroxylation reaction kettle, and performs the next circulation reaction under the action of an external circulation pump;
and 4, step 4: after the circulation reaction is finished, stopping introducing the ethylene oxide, and transferring the hydroxylation liquid generated by the circulation reaction into the next process of metronidazole production through an esterification kettle connecting pipeline.
Furthermore, before the ethylene oxide enters the external circulation pipeline, the air in the ethylene oxide introducing pipeline and the external circulation pipeline is removed through nitrogen.
The invention utilizes the characteristics of the Venturi ejector, the throat has vacuum degree, gas is easier to suck, and the entering ethylene oxide gas and the reaction liquid can be well mixed in turbulent liquid at the rear section of the Venturi ejector, thereby solving the problem of uneven distribution of the ethylene oxide in the prior art. In addition, the ethylene oxide is introduced into the Venturi ejector and then passes through a section of ascending reaction pipeline, the ascending reaction pipeline has proper length, the ethylene oxide is fully mixed with the raw material liquid after being introduced into the Venturi ejector and then reacts in the ascending reaction pipeline, and due to the fact that the ascending reaction pipeline has certain pressure and length, the residence time of the ethylene oxide in the reaction liquid is prolonged, the ethylene oxide is prevented from overflowing immediately, and the emptying and discharging of the ethylene oxide are reduced.
Compared with the prior art, the invention has the following beneficial effects:
the feeding device and the feeding process of the ethylene oxide in the metronidazole hydroxylation reaction provided by the invention reduce the ton consumption of the ethylene oxide in the metronidazole production, and simultaneously reduce the discharge of the ethylene oxide and the content of ethylene glycol in sewage. The implementation of the invention can reduce the ton consumption of ethylene oxide in metronidazole hydroxylation reaction to 0.9-1.0, thereby reducing the production cost of metronidazole and reducing the three wastes.
Drawings
FIG. 1 is a flow chart of a feeding device and a feeding process thereof for ethylene oxide in metronidazole hydroxylation reaction;
in the figure, 1-emptying pipe, 2-stirrer, 3-hydroxylation reaction kettle, 4-ethylene oxide storage tank, 5-external circulation pump, 6-first stop valve, 7-second stop valve, 8-connecting esterification kettle pipeline, 9-third stop valve, 10-fourth stop valve, 11-rising reaction pipeline, 12-nitrogen storage tank, 13-Venturi ejector, 14-external circulation pipeline, 15-hydroxylation kettle bottom valve and 16-ethylene oxide introduction pipeline.
FIG. 2 is a flow chart of the ethylene oxide feeding process in the metronidazole production process of the comparative example of the present invention;
in the figure, 1-concentrated sulfuric acid storage tank, 2-emptying pipe, 3-stirrer, 4-hydroxylation reaction kettle, 5-ethylene oxide gas guide pipe, 6-first stop valve, 7-second stop valve, 8-nitrogen storage tank, 9-ethylene oxide storage tank and 10-esterification kettle pipeline are connected.
Detailed Description
The features and advantages of the present invention will be further understood from the following detailed description taken in conjunction with the accompanying drawings. The examples are provided only as illustrations of the method of the present invention and are not intended to limit the remainder of the disclosure in any way.
Examples
As shown in fig. 1, a feeding device for ethylene oxide in metronidazole hydroxylation reaction includes a hydroxylation reaction kettle 3 and an external circulation pipeline 14 located outside the hydroxylation reaction kettle 3, wherein one end of the external circulation pipeline 14 is connected with the bottom of the hydroxylation reaction kettle 3, the other end of the external circulation pipeline is connected with the top of the hydroxylation reaction kettle 3, the external circulation pipeline 14 is sequentially provided with a hydroxylation kettle bottom valve 15, an external circulation pump 5, a venturi ejector 13, a rising reaction pipeline 11 and a first stop valve from the bottom of the hydroxylation reaction kettle 3 to the top of the hydroxylation reaction kettle 3, the throat of the venturi ejector 13 is provided with an ethylene oxide introduction pipeline 16, and the external circulation pipeline 14 is provided with an esterification kettle connecting pipeline 8 between the rising reaction pipeline 11 and the first stop valve. The ethylene oxide is stored in an ethylene oxide storage tank 4, and a third stop valve is arranged at the outlet of the ethylene oxide storage tank 4. The nitrogen is stored in the nitrogen storage tank 12, and a fourth stop valve is arranged at the outlet of the nitrogen storage tank 12. The ascending reaction pipe 5 has a pressure and a length suitable for the hydroxylation reaction.
The method is characterized in that ethylene oxide is added by adopting a feeding device of ethylene oxide in metronidazole hydroxylation reaction shown in the attached drawing 1, an external circulating pipeline is established outside a hydroxylation reaction kettle, an external circulating pump is arranged in the external circulating pipeline to provide power required by external circulation, a Venturi ejector is additionally arranged in the external circulating pipeline, the ethylene oxide is introduced into a throat of the Venturi ejector, the ethylene oxide enters the external circulating pipeline and then is fully mixed and reacted with raw material liquid, and the ethylene oxide flows through a section of ascending reaction pipeline and then returns to the hydroxylation reaction kettle to carry out circulating reaction.
The specific operation steps are as follows:
1. 810Kg of formic acid with the mass fraction of 85 percent, 540Kg of concentrated sulfuric acid and 1410Kg of 2-methyl-5-nitroimidazole are added into a hydroxylation reaction kettle 3; starting a stirrer 2 of the hydroxylation reaction kettle, heating to 85-95 ℃, and waiting for the 2-methyl-5-nitroimidazole to be completely dissolved;
2. checking that a first stop valve of the external circulation pipeline is kept in an open state, and after the preparation is finished, opening the external circulation pump 5 and a bottom valve 15 of the hydroxylation kettle to enable the reaction liquid to form external circulation;
3. and opening a fourth stop valve of the nitrogen storage tank 12 to remove air in the pipeline, closing the fourth stop valve after 3min, switching to open a third stop valve of the ethylene oxide storage tank 4, and maintaining the flow of the ethylene oxide at 140 Kg/h.
4. Controlling the jacket steam of the hydroxylation reaction kettle 3, controlling the temperature in the kettle to be 89-93 ℃, and stopping introducing the ethylene oxide after the introduced ethylene oxide reaches 700Kg through metering.
5. And after the ventilation is stopped, the circulating pump continues to circulate for 15min, the second stop valve is opened after the reaction is finished, the first stop valve is closed, the generated hydroxylation liquid is transferred into the esterification kettle through the esterification kettle connecting pipeline 8 to be discharged, and the subsequent working procedures are continued.
6. And (4) stopping the external circulating pump after the discharge is finished, closing the bottom valve 15 of the hydroxylation kettle, finishing the reaction of one batch of materials, and starting the feeding of the second batch of materials.
Comparative example
The ethylene oxide feeding process (patent 201811424478.1) in the metronidazole production method in the prior art is taken as a comparative example, the ethylene oxide feeding process in the metronidazole hydroxylation reaction production method in the prior art is shown in figure 2, and the ethylene oxide is fed in a mode that a conduit is introduced into a kettle bottom and the ethylene oxide is intermittently fed in batches. The same material input is adopted, the conversion rate of the 2-methyl-5-nitroimidazole is monitored by adopting high performance liquid chromatography, and the amount of ethylene oxide required for achieving the same conversion rate as the patent is recorded.
The specific process flow is as follows: 810kg of formic acid with the mass concentration of 85% is firstly put into an acid preparation kettle, and 540kg of 98 wt% concentrated sulfuric acid is added while stirring at the temperature of 15 ℃ to prepare mixed acid. The mixed acid is put into a hydroxylation reaction kettle containing 1410Kg of 2-methyl-5-nitroimidazole, the temperature is raised to 90 ℃ by stirring, ethylene oxide and 180Kg of 98 wt% concentrated sulfuric acid are added alternately for a plurality of times after the 2-methyl-5-nitroimidazole is completely dissolved, and liquid chromatography monitoring shows that the conversion rate of the 2-methyl-5-nitroimidazole in the embodiment is achieved, and the input amount of the ethylene oxide is about 840 Kg.
The process and effect results of the above examples and comparative examples are compared in the following table 1:
TABLE 1
The feeding process of the ethylene oxide in the metronidazole hydroxylation reaction provided by the invention can reduce the ton consumption of the ethylene oxide in the metronidazole hydroxylation reaction to 0.9-1.0, thereby reducing the production cost of metronidazole and simultaneously reducing the waste gas generated by volatilization of the ethylene oxide and the three wastes generated by hydrolysis of the ethylene oxide.
Claims (7)
1. The utility model provides a feeding device of ethylene oxide in metronidazole hydroxylation reaction which characterized in that: including hydroxylation reation kettle (3) and be located outer circulating line (14) of hydroxylation reation kettle (3), outer circulating line (14) one end with hydroxylation reation kettle (3) bottom is connected, the other end with hydroxylation reation kettle (3) top is connected, outer circulating line (14) are equipped with hydroxylation cauldron bottom valve (15), external circulation pump (5), venturi ejector (13) and rising reaction line (11) and first stop valve (6) by hydroxylation reation kettle (3) bottom to hydroxylation reation kettle (3) top in proper order, venturi ejector (13) choke point department is equipped with ethylene oxide introduction pipeline (16), outer circulating line (14) are equipped with between rising reaction line (11) and first stop valve (6) and connect esterification cauldron pipeline (8).
2. The feeding device of ethylene oxide in metronidazole hydroxylation reaction of claim 1, characterized in that: the ethylene oxide is stored in an ethylene oxide storage tank (4), and a third stop valve (9) is arranged at the outlet of the ethylene oxide storage tank (4).
3. The feeding device of the ethylene oxide in metronidazole hydroxylation reaction of claim 2, characterized in that: the nitrogen is stored in a nitrogen storage tank (12), and a fourth stop valve (10) is arranged at the outlet of the nitrogen storage tank (12).
4. The feeding device of the ethylene oxide in metronidazole hydroxylation reaction of claim 3, characterized in that: the ascending reaction conduit (5) has a pressure and a length suitable for the hydroxylation reaction.
5. A feeding process of ethylene oxide in metronidazole hydroxylation reaction is characterized in that: the feeding device of the ethylene oxide in metronidazole hydroxylation reaction as claimed in claim 4 is used, the ethylene oxide is introduced into the throat of the Venturi ejector (13), enters the external circulation pipeline (14), is fully mixed with the raw material liquid for reaction, flows through the section of ascending reaction pipeline (11), and then returns to the hydroxylation reaction kettle (3) for circulation reaction.
6. The process for feeding ethylene oxide in metronidazole hydroxylation reaction according to claim 5, wherein: comprises the following steps:
step 1: adding raw materials into a hydroxylation reaction kettle (3), heating to the reaction temperature to enable the raw materials to be dissolved clearly to obtain a raw material solution; the raw materials are formic acid, sulfuric acid and 2-methyl-5-nitroimidazole;
step 2: starting the external circulating pump (5) to allow the raw material liquid to externally circulate through the external circulating pipeline (14);
and step 3: introducing ethylene oxide into a throat of the Venturi ejector (13), wherein the ethylene oxide is fully mixed with the raw material liquid after entering an external circulating pipeline (14) to react and flows through a rising reaction pipeline (11), then returns into the hydroxylation reaction kettle (3), and then carries out the next round of circulating reaction under the action of an external circulating pump (5);
and 4, step 4: after the circulation reaction is finished, stopping introducing the ethylene oxide, and switching the hydroxylation liquid generated by the circulation reaction into the next process of metronidazole production through an esterification kettle connecting pipeline (8).
7. The process for feeding ethylene oxide in metronidazole hydroxylation reaction according to claim 6, wherein: before the ethylene oxide enters the external circulation pipeline (14), the air in the ethylene oxide introducing pipeline (16) and the external circulation pipeline (14) is removed through nitrogen.
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| CN201911049263.0A CN110975784A (en) | 2019-10-31 | 2019-10-31 | Feeding device and feeding process of ethylene oxide in metronidazole hydroxylation reaction |
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| CN201911049263.0A CN110975784A (en) | 2019-10-31 | 2019-10-31 | Feeding device and feeding process of ethylene oxide in metronidazole hydroxylation reaction |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1176796A (en) * | 1997-09-08 | 1999-03-23 | Nippon Steel Chem Co Ltd | Reaction method and device therefor |
| FR2832937A1 (en) * | 2001-12-04 | 2003-06-06 | Technip France | METHOD AND DEVICE FOR CHEMICAL REACTION BETWEEN A GAS AND AT LEAST ONE COMPOUND IN SOLUTION, IMPLEMENTED IN THE PRESENCE OF A SOLID CATALYST |
| CN203264720U (en) * | 2013-05-04 | 2013-11-06 | 安徽奔马先端科技有限公司 | Reaction kettle with mixed feeding device for chemical reaction process |
| CN103483265A (en) * | 2013-09-05 | 2014-01-01 | 湖北省宏源药业有限公司 | Metronidazole production method |
| CN203425824U (en) * | 2013-08-20 | 2014-02-12 | 湖北省宏源药业有限公司 | Metronidazole hydroxylation reaction device |
| CN206881716U (en) * | 2017-07-13 | 2018-01-16 | 黑龙江工业学院 | Chemical reaction kettle |
| CN206916038U (en) * | 2017-07-17 | 2018-01-23 | 黄冈师范学院 | A kind of device of minute-pressure synthesis metronidazole |
-
2019
- 2019-10-31 CN CN201911049263.0A patent/CN110975784A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1176796A (en) * | 1997-09-08 | 1999-03-23 | Nippon Steel Chem Co Ltd | Reaction method and device therefor |
| FR2832937A1 (en) * | 2001-12-04 | 2003-06-06 | Technip France | METHOD AND DEVICE FOR CHEMICAL REACTION BETWEEN A GAS AND AT LEAST ONE COMPOUND IN SOLUTION, IMPLEMENTED IN THE PRESENCE OF A SOLID CATALYST |
| CN203264720U (en) * | 2013-05-04 | 2013-11-06 | 安徽奔马先端科技有限公司 | Reaction kettle with mixed feeding device for chemical reaction process |
| CN203425824U (en) * | 2013-08-20 | 2014-02-12 | 湖北省宏源药业有限公司 | Metronidazole hydroxylation reaction device |
| CN103483265A (en) * | 2013-09-05 | 2014-01-01 | 湖北省宏源药业有限公司 | Metronidazole production method |
| CN206881716U (en) * | 2017-07-13 | 2018-01-16 | 黑龙江工业学院 | Chemical reaction kettle |
| CN206916038U (en) * | 2017-07-17 | 2018-01-23 | 黄冈师范学院 | A kind of device of minute-pressure synthesis metronidazole |
Non-Patent Citations (1)
| Title |
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| 李振肃 等: "《药物化学》", 31 March 1981, 化学工业出版社 * |
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