CN113024427A - Method for preparing thiram by air oxidation method - Google Patents
Method for preparing thiram by air oxidation method Download PDFInfo
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- CN113024427A CN113024427A CN202110277091.3A CN202110277091A CN113024427A CN 113024427 A CN113024427 A CN 113024427A CN 202110277091 A CN202110277091 A CN 202110277091A CN 113024427 A CN113024427 A CN 113024427A
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- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 117
- 230000003647 oxidation Effects 0.000 title claims abstract description 106
- 238000000034 method Methods 0.000 title claims abstract description 52
- KUAZQDVKQLNFPE-UHFFFAOYSA-N thiram Chemical compound CN(C)C(=S)SSC(=S)N(C)C KUAZQDVKQLNFPE-UHFFFAOYSA-N 0.000 title claims abstract description 36
- 229960002447 thiram Drugs 0.000 title claims abstract description 34
- 239000005843 Thiram Substances 0.000 title claims abstract description 32
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 70
- 239000000460 chlorine Substances 0.000 claims abstract description 70
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 70
- 238000007599 discharging Methods 0.000 claims abstract description 26
- 238000005406 washing Methods 0.000 claims abstract description 26
- QGJOPFRUJISHPQ-UHFFFAOYSA-N Carbon disulfide Chemical compound S=C=S QGJOPFRUJISHPQ-UHFFFAOYSA-N 0.000 claims abstract description 24
- 159000000000 sodium salts Chemical class 0.000 claims abstract description 20
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 claims abstract description 18
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000009833 condensation Methods 0.000 claims abstract description 9
- 230000005494 condensation Effects 0.000 claims abstract description 9
- NCTHNHPAQAVBEB-WGCWOXMQSA-M sodium ferulate Chemical compound [Na+].COC1=CC(\C=C\C([O-])=O)=CC=C1O NCTHNHPAQAVBEB-WGCWOXMQSA-M 0.000 claims abstract description 8
- 238000010521 absorption reaction Methods 0.000 claims description 38
- 239000007788 liquid Substances 0.000 claims description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 239000003513 alkali Substances 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 7
- 238000012432 intermediate storage Methods 0.000 claims description 6
- 238000003825 pressing Methods 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 3
- 229910001902 chlorine oxide Inorganic materials 0.000 claims description 2
- MAYPHUUCLRDEAZ-UHFFFAOYSA-N chlorine peroxide Chemical compound ClOOCl MAYPHUUCLRDEAZ-UHFFFAOYSA-N 0.000 claims description 2
- 238000013102 re-test Methods 0.000 claims description 2
- 239000003054 catalyst Substances 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 10
- 238000002360 preparation method Methods 0.000 abstract description 3
- 230000036632 reaction speed Effects 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 17
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 6
- 239000003960 organic solvent Substances 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 230000000844 anti-bacterial effect Effects 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000003899 bactericide agent Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000575 pesticide Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 231100000674 Phytotoxicity Toxicity 0.000 description 1
- 241000918585 Pythium aphanidermatum Species 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 125000003158 alcohol group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- QGJOPFRUJISHPQ-NJFSPNSNSA-N carbon disulfide-14c Chemical compound S=[14C]=S QGJOPFRUJISHPQ-NJFSPNSNSA-N 0.000 description 1
- 235000013339 cereals Nutrition 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- -1 thiram sodium salt Chemical class 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C333/00—Derivatives of thiocarbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
- C07C333/14—Dithiocarbamic acids; Derivatives thereof
- C07C333/30—Dithiocarbamic acids; Derivatives thereof having sulfur atoms of dithiocarbamic groups bound to other sulfur atoms
- C07C333/32—Thiuramsulfides; Thiurampolysulfides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention relates to the technical field of thiram preparation, in particular to a method for preparing thiram by an air oxidation method. A method for preparing thiram by an air oxidation method comprises the following steps: (1) feeding: starting a sodium salt pump to feed sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle; (2) and (3) oxidation: controlling the total pressure of inlet air of the oxidation reaction kettle to be less than or equal to 0.025 MPa; ensure the mixed gas is mixed with V air: 300 parts of chlorine: continuously introducing the chlorine gas into an oxidation kettle at a ratio of 1-100: 1 through a dispersing bubbler, wherein the chlorine gas pressure of the oxidation kettle is less than or equal to 0.08 MPa; (3) discharging and washing. The invention adopts chlorine as the catalyst, and the chlorine is cheap and easy to obtain, thereby reducing the production cost of the product; the chlorine adding proportion is very small, the reaction speed is mild and controllable, the cost is low, the product quality is good, the chlorine adding proportion can be smoothly applied to a production device in a large scale, and better economic benefit and social benefit are obtained.
Description
Technical Field
The invention relates to the technical field of thiram preparation, in particular to a method for preparing thiram by an air oxidation method.
Background
Thiram (chemical name: tetramethyl thiuram disulfide, common name of Chinese prescription: thiram, thiuram, TMTD) is a commonly used bactericide developed and developed by DuPont company in 1931, is a protective bactericide for treating plant leaves and seeds, is medium-toxic, has no phytotoxicity to plants, has a wide antibacterial spectrum, is mainly used for preventing and treating cereal smut and seedling-stage damping-off of various crops, can also be used for spraying and preventing diseases of fruit trees and vegetables, can be used independently or compounded with various pesticide bactericides in use, and has a good use effect. In addition, thiram is a rubber accelerator (TMTD) with good performance.
At present, thiram prepared by oxidizing thiram sodium salt generally adopts three processes of a chlorine oxidation method, a hydrogen peroxide oxidation method and an air oxidation method, and the chlorine oxidation method (CN201310642420.5) generates dilute hydrochloric acid which is very difficult to treat due to the use of a large amount of chlorine and the reaction temperature is difficult to control and is gradually eliminated; the hydrogen peroxide oxidation method (CN201710132412.4) is easy to explode and prepare drugs due to the use of hydrogen peroxide, sulfuric acid and the like, has high danger and high production cost and is difficult to apply on a large scale; the common air oxidation method (CN01104137.4) is basically stopped in a laboratory stage because the selection of a catalyst is difficult, the cost is high, the product yield is low, and the separation of the catalyst, an organic solvent and the like is difficult, and no report of large-scale application is found. The invention creatively selects a cheap and easily-obtained catalyst, has mild process reaction, low cost, high product yield and good quality, and is applied in the actual production of the pesticide thiram on a large scale.
CN01104137.4 discloses a method for preparing thiram by a common air oxidation method, which is characterized in that carbon disulfide, dimethylamine and an organic solvent are used as raw materials, and compressed dry air is introduced into the raw materials in a state of adding a catalyst, so as to prepare thiram raw powder.
Patent document CN01104137.4 shows that the organic solvent is an alcohol solvent such as methanol and isopropanol, and the catalyst is a metal salt such as copper chloride and zinc chloride. The method brings difficulty to the separation of products in the later period, and the recovery and purification equipment of the organic solvent has large investment and large difficulty in wastewater treatment, so that the industrial production is difficult to realize.
Disclosure of Invention
The invention aims to solve the technical problem that in the production process for preparing thiram by an air oxidation method, the organic solvent and the metal catalyst are difficult to separate in the later stage. The invention aims to design a method for preparing thiram by using an air oxidation method with chlorine as a catalyst. Based on the purpose, the technical scheme adopted by the invention is as follows:
a method for preparing thiram by an air oxidation method comprises the following steps:
(1) feeding: starting a sodium salt pump to feed sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle;
(2) and (3) oxidation: opening a main valve of an air buffer tank and an air inlet valve of an oxidation reaction kettle (called oxidation kettle for short), and controlling the total air inlet pressure of the oxidation kettle to be less than or equal to 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: 300 parts of chlorine: continuously introducing the chlorine gas into an oxidation kettle at a ratio of 1-100: 1 through a dispersing bubbler, wherein the chlorine gas pressure of the oxidation kettle is less than or equal to 0.08 MPa; periodically measuring the pH value of the kettle liquid, closing the chlorine 2-way valve when the pH value is measured to be 2-3, and continuing to operate the fan for 4-8 minutes and stopping operation; re-testing the pH value and still controlling the pH value to be 2-3 to reach the end point; after the oxidation is finished, closing a chlorine valve;
(3) discharging and washing: starting a discharge valve button at the bottom of the oxidation kettle, and opening a discharge bottom valve; feeding the materials into a washing kettle for washing; and (4) dewatering after the water washing is finished.
Further, still include (4) tail gas absorption system: opening a water inlet valve of the absorption tower, adding water to 55 grids of the liquid level meter, and closing the water valve; opening a valve at the bottom of the alkali metering tank, adding 4-5 lattices of alkali into the absorption tower to enable the pH value of the absorption liquid to reach 10, and then closing the valve at the bottom of the alkali metering tank; and starting a circulating pump to circulate the absorption liquid.
Further, testing the pH value of the absorption liquid in the tail gas absorption tower 1 time every 2 hours, and keeping the pH value to be more than or equal to 8; discharging the absorption liquid in the tower to 75 grids and discharging to 55 grids; and when the PH value in the absorption tower is less than 8, stopping the oxidation operation, closing the circulating pump, discharging the absorption liquid to a water treatment post, and adding water again to the alkali.
Further, a tail gas discharge port in the tail gas absorption system is provided with a chlorine-containing tail gas on-line automatic alarm instrument, and when the chlorine content is more than or equal to 65mg/m3The alarm is given and the chlorine oxide gas supply valve is automatically cut off.
Further, in the step (1), before starting the sodium salt pump for feeding, opening a discharge valve of the intermediate storage tank, a main oxidation feeding valve and a feeding valve on the oxidation kettle; starting the sodium salt pump for feeding, automatically stopping the sodium salt feeding pump when the flowmeter displays 4200 liters, and closing the discharge valve of the intermediate storage tank, the oxidation feeding main valve and the feeding valve on the oxidation kettle after the sodium salt feeding pump is stopped.
Furthermore, in the step (2), when air enters the oxidation kettle, a Roots blower is adopted for air intake.
Further, when the chlorine inlet valve is opened in the step (2), firstly opening the first valve and then opening the 2 valves; when the pH value in the oxidation kettle is more than 3, continuing opening a chlorine valve to continue chlorine introduction and oxidation; and when the oxidation end point is finished, closing the 2 chlorine valves.
Further, in the step (3), when discharging is finished, opening a water inlet valve on the oxidation kettle to clean the oxidation kettle, and closing the water inlet valve within 1-2 minutes; and after the feeding port of the washing kettle is free of materials, stopping the discharging pump of the oxidation kettle, pressing a button of a bottom valve of the oxidation kettle, closing a discharging bottom valve, and closing a feeding valve of the corresponding washing kettle.
The invention has the following beneficial effects: (1) the invention adopts chlorine as the catalyst, and the chlorine is cheap and easy to obtain, thereby reducing the production cost of the product; (2) the chlorine adding proportion is very small, the reaction speed is mild and controllable, the cost is low, the product quality is good, the chlorine adding proportion can be smoothly applied to a production device in a large scale, and better economic benefit and social benefit are obtained; (3) and chlorine is used as a catalyst, so that the product is convenient and simple to separate in the later period, and waste water and waste gas generated in production are convenient to collect and treat.
Drawings
FIG. 1 is a flow diagram of an oxidation process of the present invention;
FIG. 2 is a flow chart of the start-up sequence of the oxidation station.
Detailed Description
The invention is further described below with reference to examples and figures.
Conveying the sodium salt solution from the condensation position to an oxidation kettle through a pump, reacting under the action of a small amount of chlorine to generate TMTD, and determining the reaction end point when the pH value of the material is 2-3. And after the end point is reached, the materials are conveyed to a washing kettle through a discharge pump for washing, and then are conveyed to a dehydration process. And the tail gas of the oxidation kettle is subjected to alkali absorption by a tail gas absorption tower and then is discharged after reaching the standard. The oxidation reaction equation is as follows:
a method for preparing thiram by an air oxidation method comprises the following steps:
(1) feeding: starting a sodium salt pump to feed sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle. Specifically, as follows, the following description will be given,
1) opening 3 storage tank valves (one or two of them are opened according to the concrete situation) of the intermediate storage tank discharge valve, opening an oxidation feeding main valve, and opening a feeding valve on the oxidation kettle;
2) starting the sodium salt pump for feeding, and automatically stopping the sodium salt pump when the flowmeter displays about 4200 liters;
3) closing the discharge valve of the intermediate storage tank, and closing the oxidation feeding main valve and the feeding valve on the oxidation kettle.
(2) And (3) oxidation:
the oxidation process is shown in figure 2, air and chlorine gas respectively enter a mixing tank from an air buffer tank and a chlorine gas distribution tank to be mixed, then enter an oxidation kettle, sodium salt is added into the oxidation kettle, and waste gas generated in the oxidation process enters a tail gas absorption tower.
1) Opening a main valve of an air buffer tank and an air inlet valve of an oxidation kettle, and starting a Roots blower (one of two blowers is opened, and the two blowers are opened according to actual conditions); controlling the total pressure of inlet air of the oxidation kettle to be not more than 0.025 MPa;
2) opening a chlorine inlet valve of the chlorine distribution tank (a workshop chlorine main valve needs to be opened when the vehicle is restored after overhaul or long-time parking), opening the first valve at first, then opening 2 valves, and controlling the pressure of chlorine entering the oxidation kettle to be not more than 0.08 Mpa;
3) when the pH value is detected to be 2-3, closing the chlorine 2-way valve, and continuing to operate the fan for 5 minutes and stopping operation; and (4) retesting the pH value and controlling the pH value to be 2-3, if the pH value is not in place, opening a chlorine valve to continue introducing chlorine for oxidation until the end point is reached.
4) And (3) closing the 2 chlorine valves after the oxidation end point, and if stopping for maintenance or long-time non-feeding oxidation, closing the first chlorine valve and a workshop chlorine main valve.
(3) Discharging and washing:
1) starting a button of a discharge valve at the bottom of the oxidation kettle A, and opening a discharge bottom valve;
2) starting the discharging pump of the oxidation kettle, and starting a feeding valve of the washing kettle according to the condition of the feed liquid in the washing kettle.
3) When the discharging is finished, opening a water inlet valve on the oxidation kettle to clean the oxidation kettle, and closing the water inlet valve after about 1 minute (on the premise of ensuring that the oxidation kettle is cleaned completely);
4) and after the feeding port of the washing kettle is free of materials, stopping the discharging pump of the oxidation kettle, pressing a button of a bottom valve of the oxidation kettle, closing a discharging bottom valve, and closing a feeding valve of the corresponding washing kettle.
(4) Tail gas absorption system:
before starting, the following preparation work is needed, 1) whether water, electricity, instruments and meters, pipe valves and equipment are intact and normal is checked;
2) opening a water inlet valve of the absorption tower, adding water to 55 grids of the liquid level meter, and closing the water valve;
3) opening a valve at the bottom of an alkali metering tank, adding 4-5 lattices of alkali (the content is about 32 percent) into the absorption tower to enable the pH value of the absorption liquid to reach about 10, and then closing the valve at the bottom of the alkali metering tank;
4) and starting a circulating pump to circulate the absorption liquid, and checking the current and the running condition of the pump.
During the operation, the following requirements are noted.
A. Normal operating requirements
1) Testing the pH value of the absorption liquid before the oxidation absorption operation, controlling the pH value not to be less than 8, controlling the detection frequency to be 1 time/2 hours, and discharging the absorption liquid to 55 grids after the absorption liquid reaches 75 grids to prevent the absorption liquid from being excessive;
2) when the pH value is less than 8, stopping the oxidation operation, closing the circulating pump, discharging the absorption liquid to a water treatment post, and adding water again to the alkali.
B. Analysis frequency and recording requirements
1) Detecting the pH value of the absorption liquid every 2 hours under the normal production condition and recording;
2) the analysis room is responsible for sampling and checking the concentration of the absorption liquid alkali for at least 1 time per shift;
3) the pH value of the device is required to be detected and recorded before the device is started again after the device is stopped in midway;
4) and a tail gas discharge port is provided with a chlorine-containing tail gas online automatic alarm instrument, when the chlorine content is more than or equal to 65mg/m3, an alarm is given, an oxidation chlorine gas supply valve is automatically cut off, abnormal conditions are recorded and analyzed, the reason is found, and measures are taken.
The standard of the thiram product prepared by the method conforms to HG3757-2004, and the method comprises the following steps:
the production process mainly uses the following equipment: the sodium oxide salt purification device comprises a sodium oxide salt feeding pump, an oxidation kettle, an air distributor, a fan, a washing kettle, an oxidation kettle discharge pump, a washing tower and a circulating pump.
The main process index table is as follows:
the specific implementation mode is as follows:
example 1
Starting the sodium salt pump to 7m3Feeding 4200L sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle, opening a main valve of an air buffer tank, and controlling the total inlet air pressure of the oxidation kettle to be not more than 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: 100 parts of chlorine: the proportion of 1 is continuously introduced into the oxidation kettle through a special dispersing bubbler, the pH value of kettle liquid is periodically measured, when the pH value is measured to be 2-3, a chlorine 2-way valve is closed, and a fan continues to operate for 5 minutes and stops operating; and (5) retesting the pH value and controlling the pH value to be 2-3 to reach the end point. The reaction time is about 2 hours, and 300Kg of thiram raw powder is obtained after discharging, washing and drying.
Example 2
Starting the sodium salt pump to 7m3Feeding 4200L sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle, opening a main valve of an air buffer tank, and controlling the total inlet air pressure of the oxidation kettle to be not more than 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: chlorine V150: the proportion of 1 is continuously introduced into the oxidation kettle through a special dispersing bubbler, the pH value of kettle liquid is periodically measured, when the pH value is measured to be 2-3, a chlorine 2-way valve is closed, and a fan continues to operate for 5 minutes and stops operating; and (5) retesting the pH value and controlling the pH value to be 2-3 to reach the end point. The reaction time is about 3 hours, and 302Kg of thiram raw powder is obtained after discharging, washing and drying.
Example 3
Starting the sodium salt pump to 7m3Feeding 4200L sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle, opening a main valve of an air buffer tank, and controlling the total inlet air pressure of the oxidation kettle to be not more than 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: v chlorine 200: the proportion of 1 is continuously introduced into the oxidation kettle through a special dispersing bubbler, the pH value of kettle liquid is periodically measured, and when the pH value is measuredWhen the pH value is 2-3, closing the chlorine 2-way valve, and continuing to operate the fan for 5 minutes and stopping operation; and (5) retesting the pH value and controlling the pH value to be 2-3 to reach the end point. The reaction time is about 4 hours, and 305Kg of thiram raw powder is obtained after discharging, washing and drying.
Example 4
Starting the sodium salt pump to 7m3Feeding 4200L sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle, opening a main valve of an air buffer tank, and controlling the total inlet air pressure of the oxidation kettle to be not more than 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: 300 parts of chlorine: the proportion of 1 is continuously introduced into the oxidation kettle through a special dispersing bubbler, the pH value of kettle liquid is periodically measured, when the pH value is measured to be 2-3, a chlorine 2-way valve is closed, and a fan continues to operate for 5 minutes and stops operating; and (5) retesting the pH value and controlling the pH value to be 2-3 to reach the end point. The reaction time is about 3 hours, and 298Kg of thiram raw powder is obtained after discharging, washing and drying.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Finally, it should be noted that: the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; thus, while the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted; all such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.
Claims (8)
1. A method for preparing thiram by an air oxidation method is characterized by comprising the following steps: the method comprises the following steps:
(1) feeding: starting a sodium salt pump to feed sodium ferulate prepared by alkaline condensation of carbon disulfide and dimethylamine into an oxidation reaction kettle;
(2) and (3) oxidation: opening a main valve of an air buffer tank and an air inlet valve of the oxidation kettle, and controlling the total air inlet pressure of the oxidation kettle to be less than or equal to 0.025 MPa; opening a chlorine inlet valve of chlorine, controlling chlorine pressure and flow, and ensuring that the mixed gas is mixed with V air: 300 parts of chlorine: continuously introducing the chlorine gas into an oxidation kettle at a ratio of 1-100: 1 through a dispersing bubbler, wherein the chlorine gas pressure of the oxidation kettle is less than or equal to 0.08 MPa; periodically measuring the pH value of the kettle liquid, closing the chlorine 2-way valve when the pH value is measured to be 2-3, and continuing to operate the fan for 4-8 minutes and stopping operation; re-testing the pH value and still controlling the pH value to be 2-3 to reach the end point; after the oxidation is finished, closing a chlorine valve;
(3) discharging and washing: starting a discharge valve button at the bottom of the oxidation kettle, and opening a discharge bottom valve; feeding the materials into a washing kettle for washing; and (4) dewatering after the water washing is finished.
2. The method for preparing thiram by the air oxidation method according to claim 1, wherein: still include (4) tail gas absorption system: opening a water inlet valve of the tail gas absorption tower, adding water to 55 grids of the liquid level meter, and closing the water valve; opening a valve at the bottom of the alkali metering tank, adding 4-5 lattices of alkali into the absorption tower to enable the pH value of the absorption liquid to reach 10, and then closing the valve at the bottom of the alkali metering tank; and starting a circulating pump to circulate the absorption liquid.
3. The method for preparing thiram by the air oxidation method according to claim 2, wherein: testing the pH value of the absorption liquid in the tail gas absorption tower 1 time every 2 hours, and keeping the pH value to be more than or equal to 8; discharging the absorption liquid in the tower to 75 grids and discharging to 55 grids; and when the PH value in the absorption tower is less than 8, stopping the oxidation operation, closing the circulating pump, discharging the absorption liquid to a water treatment post, and adding water again to the alkali.
4. The method for preparing thiram by the air oxidation method according to claim 2, wherein: the tail gas discharge port in the tail gas absorption system is provided with a chlorine tailThe gas on-line automatic alarm device is used when the chlorine content is more than or equal to 65mg/m3The alarm is given and the chlorine oxide gas supply valve is automatically cut off.
5. The method for preparing thiram by the air oxidation method according to claim 1, wherein: in the step (1), before starting the sodium salt pump for feeding, opening a discharge valve of an intermediate storage tank, an oxidation feeding main valve and a feeding valve on an oxidation kettle; starting the sodium salt pump for feeding, automatically stopping the sodium salt feeding pump when the flowmeter displays 4200 liters, and closing the discharge valve of the intermediate storage tank, the oxidation feeding main valve and the feeding valve on the oxidation kettle after the sodium salt feeding pump is stopped.
6. The method for preparing thiram by the air oxidation method according to claim 1, wherein in the step (2), air is introduced by a Roots blower when entering the oxidation kettle.
7. The method for preparing thiram by the air oxidation method according to claim 1, wherein in the step (2), when the chlorine gas inlet valve is opened, the first valve is opened first, and then the 2 valves are opened; when the pH value in the oxidation kettle is more than 3, continuing opening a chlorine valve to continue chlorine introduction and oxidation; and when the oxidation end point is finished, closing the 2 chlorine valves.
8. The method for preparing thiram by the air oxidation method according to claim 1, wherein in the step (3), when the discharging is finished, an inlet valve on the oxidation kettle is opened to clean the oxidation kettle, and the inlet valve is closed within 1-2 minutes; and after the feeding port of the washing kettle is free of materials, stopping the discharging pump of the oxidation kettle, pressing a button of a bottom valve of the oxidation kettle, closing a discharging bottom valve, and closing a feeding valve of the corresponding washing kettle.
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| US3147308A (en) * | 1962-05-11 | 1964-09-01 | Du Pont | Process for preparing tetramethylthiuram disulfide |
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| US3147308A (en) * | 1962-05-11 | 1964-09-01 | Du Pont | Process for preparing tetramethylthiuram disulfide |
| CN106966935A (en) * | 2017-03-30 | 2017-07-21 | 山东斯递尔化工科技有限公司 | A kind of method that utilization micro-reaction device continuously prepares tetramethylthiuram disulfide |
| CN107286066A (en) * | 2017-08-07 | 2017-10-24 | 山东尚舜化工有限公司 | A kind of technique and system of continuous production vulcanization of rubber accelerant disulfide tetra methylthiuram |
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Application publication date: 20210625 |