CN111205319A - Continuous synthesis method and system of glyphosate - Google Patents
Continuous synthesis method and system of glyphosate Download PDFInfo
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- 239000005562 Glyphosate Substances 0.000 title claims abstract description 81
- XDDAORKBJWWYJS-UHFFFAOYSA-N glyphosate Chemical compound OC(=O)CNCP(O)(O)=O XDDAORKBJWWYJS-UHFFFAOYSA-N 0.000 title claims abstract description 81
- 229940097068 glyphosate Drugs 0.000 title claims abstract description 81
- 238000001308 synthesis method Methods 0.000 title claims abstract description 22
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 465
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 206
- 239000007788 liquid Substances 0.000 claims abstract description 149
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 claims abstract description 70
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 59
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 59
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 claims abstract description 54
- 238000002156 mixing Methods 0.000 claims abstract description 52
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 claims abstract description 46
- NKDDWNXOKDWJAK-UHFFFAOYSA-N dimethoxymethane Chemical compound COCOC NKDDWNXOKDWJAK-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000002002 slurry Substances 0.000 claims abstract description 39
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 33
- 239000004471 Glycine Substances 0.000 claims abstract description 23
- 229930040373 Paraformaldehyde Natural products 0.000 claims abstract description 22
- 229920002866 paraformaldehyde Polymers 0.000 claims abstract description 22
- 229940050176 methyl chloride Drugs 0.000 claims abstract description 17
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000003513 alkali Substances 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims abstract description 7
- 230000007062 hydrolysis Effects 0.000 claims description 50
- 238000002425 crystallisation Methods 0.000 claims description 47
- 230000008025 crystallization Effects 0.000 claims description 47
- 238000000926 separation method Methods 0.000 claims description 38
- 238000010992 reflux Methods 0.000 claims description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 30
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 24
- 238000009833 condensation Methods 0.000 claims description 24
- 230000005494 condensation Effects 0.000 claims description 24
- 230000020477 pH reduction Effects 0.000 claims description 23
- 238000001816 cooling Methods 0.000 claims description 22
- 239000012530 fluid Substances 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 21
- 238000007259 addition reaction Methods 0.000 claims description 13
- 238000012691 depolymerization reaction Methods 0.000 claims description 13
- 238000005406 washing Methods 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 238000006482 condensation reaction Methods 0.000 claims description 7
- 239000007791 liquid phase Substances 0.000 claims description 4
- 239000006227 byproduct Substances 0.000 abstract description 7
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 191
- 239000000243 solution Substances 0.000 description 41
- 239000000047 product Substances 0.000 description 40
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 22
- 238000011084 recovery Methods 0.000 description 21
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Inorganic materials [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 16
- 238000001035 drying Methods 0.000 description 12
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 10
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 10
- 238000007599 discharging Methods 0.000 description 9
- 239000002994 raw material Substances 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 8
- CZHYKKAKFWLGJO-UHFFFAOYSA-N dimethyl phosphite Chemical compound COP([O-])OC CZHYKKAKFWLGJO-UHFFFAOYSA-N 0.000 description 7
- 230000003068 static effect Effects 0.000 description 7
- 239000003518 caustics Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 235000011121 sodium hydroxide Nutrition 0.000 description 6
- 239000012071 phase Substances 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- 239000002351 wastewater Substances 0.000 description 5
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- WOAWYKPABZNBBV-UHFFFAOYSA-N 2-[bis(hydroxymethyl)amino]acetic acid Chemical compound OCN(CO)CC(O)=O WOAWYKPABZNBBV-UHFFFAOYSA-N 0.000 description 3
- 125000005907 alkyl ester group Chemical group 0.000 description 3
- -1 alkyl phosphates Chemical class 0.000 description 3
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- 238000004065 wastewater treatment Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 108010077895 Sarcosine Proteins 0.000 description 1
- 239000002535 acidifier Substances 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 230000004071 biological effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007810 chemical reaction solvent Substances 0.000 description 1
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 description 1
- 229940106681 chloroacetic acid Drugs 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000002363 herbicidal effect Effects 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- FSYKKLYZXJSNPZ-UHFFFAOYSA-N sarcosine Chemical compound C[NH2+]CC([O-])=O FSYKKLYZXJSNPZ-UHFFFAOYSA-N 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
- C07F9/02—Phosphorus compounds
- C07F9/28—Phosphorus compounds with one or more P—C bonds
- C07F9/38—Phosphonic acids [RP(=O)(OH)2]; Thiophosphonic acids ; [RP(=X1)(X2H)2(X1, X2 are each independently O, S or Se)]
- C07F9/3804—Phosphonic acids [RP(=O)(OH)2]; Thiophosphonic acids ; [RP(=X1)(X2H)2(X1, X2 are each independently O, S or Se)] not used, see subgroups
- C07F9/3808—Acyclic saturated acids which can have further substituents on alkyl
- C07F9/3813—N-Phosphonomethylglycine; Salts or complexes thereof
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/48—Preparation of compounds having groups
- C07C41/50—Preparation of compounds having groups by reactions producing groups
- C07C41/56—Preparation of compounds having groups by reactions producing groups by condensation of aldehydes, paraformaldehyde, or ketones
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of glyphosate production, in particular to a continuous synthesis method and a continuous synthesis system for glyphosate. The continuous synthesis method comprises the following steps: under the action of triethylamine, glycine, paraformaldehyde and dialkyl phosphite are reacted in methanol, the obtained synthetic liquid is acidified, the obtained acidified liquid is subjected to primary hydrolysis reaction and secondary hydrolysis reaction, slurry after the secondary hydrolysis reaction is crystallized to obtain glyphosate, and gas after the secondary hydrolysis reaction is condensed to obtain condensate and non-condensable gas; mixing gas, non-condensable gas and alkali liquor generated by the primary hydrolysis reaction, carrying out neutralization reaction, carrying out steam stripping on the obtained solution and condensate, carrying out primary rectification on the obtained gas and the gas obtained by the neutralization reaction, and carrying out secondary rectification on the obtained tower bottom liquid to obtain methanol; performing third rectification on the tower top low-boiling-point substance of the first rectification to obtain methyl chloride; and rectifying the tower bottoms of the third rectification by a fourth rectification to obtain methylal. The yield of the glyphosate is high, and byproducts can be effectively recovered.
Description
Technical Field
The invention relates to the technical field of glyphosate production, in particular to a continuous synthesis method and a continuous synthesis system for glyphosate.
Background
Glyphosate is a highly effective, low toxicity, broad spectrum, biocidal, non-selective herbicide with excellent biological properties. At present, the domestic main stream production process of glyphosate has two routes: alkyl ester process (glycine process) and iminodiacetic acid process (IDA process). The foreign production process is mainly the iminodiacetic acid method of Monsanto in America. The glyphosate in China is mainly produced by an alkyl ester method taking glycine and dimethyl phosphite as main raw materials, the method takes methanol as a reaction solvent, the glycine firstly reacts with polyformaldehyde in the presence of a catalyst triethylamine to form N, N-dimethylolglycine, then the N, N-dimethylolglycine reacts with dimethyl phosphite, and hydrochloric acid is added to hydrolyze the N, N-dimethylolglycine to generate the glyphosate and byproducts methylal and methyl chloride. The main components of the tail gas generated by hydrolyzing the glyphosate synthetic liquid by the glycine method are a mixture of water, methylal, methanol, hydrogen chloride and chloromethane, and the recovery process of the tail gas is referred to as solvent recovery in the glyphosate industry. The synthetic solution is a mixed solution of an organophosphorus intermediate (glyphosate precursor) such as N-methoxyalkyl ester methylglycine as a main component, which is obtained by depolymerizing, condensing and esterifying raw materials such as methanol, paraformaldehyde (or other formaldehyde sources), glycine (or other raw materials starting from chloroacetic acid), dimethyl phosphite (or other alkyl phosphates).
The existing glyphosate hydrolysis process is intermittent hydrolysis, after a synthetic solution and hydrochloric acid in a certain proportion are mixed in a hydrolysis kettle, steam is introduced to raise the temperature to the reaction end point, the hydrolysis reaction is carried out along with the raising of the hydrolysis temperature, the steam of methylal, methanol, chloromethane, water, hydrogen chloride and the like is evaporated out from the reaction kettle, three-stage condensation is carried out, the non-condensable gas of crude chloromethane (containing air and acidity) is treated by a chloromethane recovery device, and a condensate (diluted methanol) is treated by a solvent recovery device.
Patent CN103739625B discloses a continuous hydrolysis process for preparing glyphosate by a glycine method, which comprises the steps of separating gas from liquid of mixed acid, respectively feeding the liquid and the condensed gas into a methylal tower to recover methylal, feeding kettle bottom liquid recovered from the methylal into a methanol recovery tower to recover methanol, and feeding kettle bottom liquid discharged from the methanol recovery tower into a hydrolysis kettle to complete hydrolysis reaction. The method has the advantages of low recovery rate of methylal and high energy consumption.
The traditional recovery process is to condense hydrolysis steam, wherein methanol, methylal, water and a small amount of hydrogen chloride gas with relatively high boiling points are condensed into a liquid phase, which is called dilute methanol; the chloromethane is in gas phase, and is purified by water washing, alkali washing and sulfuric acid drying to obtain chloromethane gas, and the chloromethane product is obtained by compression and condensation. Adding alkali into the condensed dilute methanol for neutralization, respectively recovering methanol and methylal in the dilute methanol by two rectifying towers, recycling the methanol as a solvent to a glyphosate synthesis link, and taking the methylal as a byproduct.
Patent CN108380029A discloses a system and a process for recovering glyphosate solvent by alkyl ester method, the tail gas of glyphosate hydrolysis is sent to a condenser for condensation and separation after neutralization, pressure control and temperature control, the condensate is sent to a diluted methanol solution recovery tank, and the non-condensable gas is sent to a methyl chloride recovery device.
The two processes of hydrolysis and solvent recovery in the glyphosate production process are main processes of steam consumption, a large amount of materials such as methanol, methylal, water and the like are condensed into liquid state, and then enter the tower again to consume a large amount of steam for heating into a steam state, so that the heat of the hydrolyzed steam is wasted, a large amount of generated steam is additionally consumed, and great heat waste is caused.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a continuous synthesis method and system for glyphosate, wherein the continuous synthesis method for glyphosate provided by the present invention has the advantages of simple process, high glyphosate yield, effective byproduct recovery and low cost.
The invention provides a continuous synthesis method of glyphosate, which comprises the following steps:
A) reacting glycine, paraformaldehyde and dialkyl phosphite in methanol under the action of triethylamine, and acidifying the reacted synthetic liquid to obtain acidified liquid;
B) carrying out primary hydrolysis reaction on the acidizing fluid at 90-112 ℃ and under-5-20 KPa;
C) performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction at 115-130 ℃ and-10 KPa, crystallizing slurry obtained after the secondary hydrolysis reaction to obtain glyphosate, and condensing gas obtained after the secondary hydrolysis reaction to obtain condensate and non-condensable gas;
mixing the gas generated by the primary hydrolysis reaction, the non-condensable gas and alkali liquor, and performing neutralization reaction;
D) mixing the solution after the neutralization reaction with the condensate, carrying out steam stripping, carrying out first rectification on the gas obtained by steam stripping and the gas obtained by the neutralization reaction at-10 KPa and the tower kettle temperature of 65-85 ℃, and carrying out second rectification on the tower kettle liquid obtained by the first rectification at 0.1-0.8 MPa and the tower kettle temperature of 85-170 ℃ to obtain methanol; performing third rectification on the tower top low-boiling-point substances obtained by the first rectification at the temperature of 0-80 KPa, the tower kettle temperature of 55-70 ℃ and the tower top temperature of-10-20 ℃ to obtain methyl chloride; and performing fourth rectification on the tower bottom liquid obtained by the third rectification at the temperature of 65-85 ℃ at 0-30 KPa to obtain methylal.
Preferably, in step a), the reaction comprises:
a1) carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 40-55 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at the temperature of 40-55 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at the temperature of 40-55 ℃ to obtain synthetic liquid.
Preferably, in the step A), the acidification temperature is 35-55 ℃, and the acidification pressure is-10 KPa.
Preferably, in the step C), the pH value of the slurry after the secondary hydrolysis reaction is crystallized is 0.1-3;
the crystallization comprises the following steps:
first-stage crystallization is carried out under the conditions that the vacuum degree is 0.083-0.093 MPa and the temperature is 55-65 ℃;
performing secondary crystallization at a vacuum degree of 0.090-0.096 MPa and a temperature of 42-49 ℃;
then carrying out three-stage crystallization at a vacuum degree of 0.097-0.101 MPa and a temperature of 28-32 ℃;
the condensation is vacuum cooling, and the pressure of the vacuum cooling is more than or equal to-70 KPa; or the condensation is water adding cooling or heat exchanger cooling, and the temperature after water adding cooling is 30-90 ℃.
Preferably, in the step C), the temperature of the neutralization reaction is 70-90 ℃, and the pressure is-5-10 KPa.
Preferably, in the step D), the temperature of the stripping tower kettle is 100-108 ℃, and the stripping pressure is-5-30 KPa;
the reflux ratio of the first rectification is 1-4: 1; the reflux ratio of the second rectification is 1-4: 1; the reflux ratio of the third rectification is 1-3.5: 1; the reflux ratio of the fourth rectification is 0.5-2: 1.
preferably, in step D), the second rectification comprises low-pressure methanol rectification and high-pressure methanol rectification;
the pressure of the low-pressure methanol rectification is 0.1-0.3 MPa, the temperature of a tower kettle is 85-120 ℃, and the reflux ratio is 1-4: 1;
the pressure of the high-pressure methanol rectification is 0.4-0.8 MPa, the temperature of a tower kettle is 135-170 ℃, and the reflux ratio is 1-4: 1.
the invention also provides a continuous synthesis system of glyphosate, which comprises:
a synthesis kettle;
the first mixing device is connected with a synthetic liquid outlet of the synthetic kettle;
the first-stage hydrolysis reaction device is connected with the acidizing fluid outlet of the first mixing device;
the second-stage hydrolysis reaction device is connected with a product solution outlet of the first-stage hydrolysis reaction device;
the crystallizer is connected with a slurry outlet of the secondary hydrolysis reaction device;
the hydrolysis tail gas condenser is connected with a gas outlet of the secondary hydrolysis reaction device;
the first gas inlet is connected with the gas outlet of the hydrolysis tail gas condenser; a second gas inlet of the alkaline tower is connected with a gas outlet of the first mixing device; a third gas inlet of the alkaline tower is connected with a gas outlet of the primary hydrolysis reaction device;
the first liquid inlet is connected with the liquid outlet of the alkaline tower; a second liquid inlet of the second mixing device is connected with a liquid outlet of the hydrolysis tail gas condenser;
a stripper having a first liquid inlet coupled to the liquid outlet of the second mixing device;
the first gas inlet is connected with the gas outlet of the alkaline washing tower; the second gas inlet of the separation tower is connected with the gas outlet of the stripping tower;
a methanol column connected to the liquid outlet of the separation column;
a methane-removing column connected to the gas outlet of the separation column;
and the formaldehyde condensation tower is connected with a liquid outlet of the methane-removing tower.
Preferably, the first-stage hydrolysis reaction device comprises a first-stage hydrolysis reaction tower and a first-stage hydrolysis reaction kettle;
the product solution outlet of the first-stage hydrolysis reaction tower is connected with the product solution inlet of the first-stage hydrolysis reaction kettle;
the gas outlet of the primary hydrolysis reaction kettle is connected with the gas inlet of the primary hydrolysis reaction tower;
the secondary hydrolysis reaction device comprises a secondary hydrolysis reaction kettle;
and a product solution inlet of the second-stage hydrolysis reaction kettle is connected with a product solution outlet of the first-stage hydrolysis reaction kettle.
Preferably, the methanol tower comprises a low pressure methanol tower and a high pressure methanol tower;
the liquid inlet of the low-pressure methanol tower is connected with the liquid outlet of the separation tower;
the liquid inlet of the high-pressure methanol tower is connected with the liquid outlet of the low-pressure methanol tower;
and a liquid outlet of the high-pressure methanol tower is connected with a second liquid phase inlet of the stripping tower.
The invention provides a continuous synthesis method of glyphosate, which comprises the following steps: A) reacting glycine, paraformaldehyde and dialkyl phosphite in methanol under the action of triethylamine, and acidifying the reacted synthetic liquid to obtain acidified liquid; B) carrying out primary hydrolysis reaction on the acidizing fluid at 90-112 ℃ and under-5-20 KPa; C) performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction at 115-130 ℃ and-10 KPa, crystallizing slurry obtained after the secondary hydrolysis reaction to obtain glyphosate, and condensing gas obtained after the secondary hydrolysis reaction to obtain condensate and non-condensable gas; mixing the gas generated by the primary hydrolysis reaction, the non-condensable gas and alkali liquor, and performing neutralization reaction; D) mixing the solution after the neutralization reaction with the condensate, carrying out steam stripping, carrying out first rectification on the gas obtained by steam stripping and the gas obtained by the neutralization reaction at-10 MPa and the temperature of a tower kettle of 65-85 ℃, and carrying out second rectification on the tower kettle liquid obtained by the first rectification at 0.1-0.8 MPa and the temperature of the tower kettle of 100-165 ℃ to obtain methanol; performing third rectification on the tower top low-boiling-point substances obtained by the first rectification at the temperature of 0-80 KPa, the tower kettle temperature of 55-70 ℃ and the tower top temperature of-10-20 ℃ to obtain methyl chloride; and performing fourth rectification on the tower bottom liquid obtained by the third rectification at the temperature of 65-85 ℃ at 0-30 KPa to obtain methylal. The continuous synthesis method of glyphosate provided by the invention has the advantages of simple process and high glyphosate yield, and can effectively recover byproducts.
Drawings
FIG. 1 is a schematic flow diagram of a continuous glyphosate synthesis system according to an embodiment of the present invention;
FIG. 2 is a schematic flow diagram of a continuous synthesis system for glyphosate according to another embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a continuous synthesis method of glyphosate, which comprises the following steps:
A) reacting glycine, paraformaldehyde and dialkyl phosphite in methanol under the action of triethylamine, and acidifying the reacted synthetic liquid to obtain acidified liquid;
B) carrying out primary hydrolysis reaction on the acidizing fluid at 90-112 ℃ and under-5-20 KPa;
C) performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction at 115-130 ℃ and-10 KPa, crystallizing slurry obtained after the secondary hydrolysis reaction to obtain glyphosate, and condensing gas obtained after the secondary hydrolysis reaction to obtain condensate and non-condensable gas;
mixing the gas generated by the primary hydrolysis reaction, the non-condensable gas and alkali liquor, and performing neutralization reaction;
D) mixing the solution after the neutralization reaction with the condensate, carrying out steam stripping, carrying out first rectification on the gas obtained by steam stripping and the gas obtained by the neutralization reaction at-10 MPa and the temperature of a tower kettle of 65-85 ℃, and carrying out second rectification on the tower kettle liquid obtained by the first rectification at 0.1-0.8 MPa and the temperature of the tower kettle of 100-165 ℃ to obtain methanol; performing third rectification on the tower top low-boiling-point substances obtained by the first rectification at the temperature of 0-80 KPa, the tower kettle temperature of 55-70 ℃ and the tower top temperature of-10-20 ℃ to obtain methyl chloride; and performing fourth rectification on the tower bottom liquid obtained by the third rectification at the temperature of 65-85 ℃ at 0-30 KPa to obtain methylal.
The invention firstly reacts glycine, paraformaldehyde and dialkyl phosphite in methanol under the action of triethylamine.
In certain embodiments of the invention, the reaction comprises:
a1) carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 40-55 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at the temperature of 40-55 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at the temperature of 40-55 ℃ to obtain synthetic liquid.
In certain embodiments of the present invention, the mass ratio of the methanol to the triethylamine to the paraformaldehyde is 4750 to 5700: 1615-1710: 950. in certain embodiments, the mass ratio of methanol, triethylamine, and paraformaldehyde is 5200: 1630: 950 or 5400: 1650: 950. in some embodiments of the invention, the mass ratio of glycine to paraformaldehyde is 1045-1250: 950. in certain embodiments, the mass ratio of glycine to paraformaldehyde is 1200: 950 or 1250: 950. in certain embodiments of the present invention, the mass ratio of the dialkyl phosphite to the paraformaldehyde is 1995-2185: 950. in certain embodiments, the mass ratio of dialkyl phosphite to paraformaldehyde is 2060: 950 or 2100: 950. in certain embodiments of the invention, the dialkyl phosphite is dimethyl phosphite.
In certain embodiments of the invention, the temperature of the depolymerization reaction is 45 ℃ or 50 ℃. In certain embodiments of the invention, the temperature of the addition reaction is 50 ℃ or 45 ℃. In certain embodiments of the invention, the temperature of the condensation reaction is 50 ℃ or 45 ℃.
In certain embodiments of the invention, the reaction in step a) is carried out in a synthesis kettle.
And after the synthetic liquid is obtained, acidifying the synthetic liquid to obtain acidified liquid.
In certain embodiments of the invention, the acidifying agent used for the acidification is hydrochloric acid. In some embodiments of the invention, the acidification temperature is 35-55 ℃, and the acidification pressure is-10 KPa. In some embodiments, the acidification temperature is 40-55 ℃, 50 ℃ or 40 ℃, and the acidification pressure is-5 KPa or 0KPa or 5 KPa.
In certain embodiments of the invention, the acidification is performed in a first mixing device.
After obtaining the acidizing fluid, carrying out primary hydrolysis reaction on the acidizing fluid at the temperature of 90-112 ℃ and under the pressure of-5-20 KPa.
In certain embodiments of the present invention, the acidified liquid further comprises, prior to performing the first stage hydrolysis reaction: and cooling the acidizing fluid. In some embodiments of the present invention, the temperature after cooling is 30 to 60 ℃. In certain embodiments of the invention, the cooling is performed in an acidification cooler.
In some embodiments of the present invention, the temperature of the primary hydrolysis reaction is 100-110 ℃, 108 ℃ or 100 ℃, and the pressure is 3-12 KPa, 10KPa or 5 KPa. In certain embodiments of the present invention, the first hydrolysis reaction is conducted in a first hydrolysis reaction unit.
And after the first-stage hydrolysis reaction is finished, performing a second-stage hydrolysis reaction on the product solution of the first-stage hydrolysis reaction at 115-130 ℃ and-10 KPa.
In some embodiments of the invention, the temperature of the secondary hydrolysis reaction is 115-125 ℃, 120 ℃ or 115 ℃, and the pressure is-5 KPa, -5KPa or 0 KPa. In certain embodiments of the invention, the secondary hydrolysis reaction is carried out in a secondary hydrolysis reaction apparatus.
And after the secondary hydrolysis reaction is finished, crystallizing the slurry after the secondary hydrolysis reaction to obtain glyphosate, and condensing the gas after the secondary hydrolysis reaction to obtain condensate and non-condensable gas.
In some embodiments of the invention, before the crystallization, the pH of the slurry after the secondary hydrolysis reaction is adjusted to 0.1 to 3, 0.1, or 2.
In some embodiments of the invention, the discharge flow rate of the crystals is 3-20 m3/h。
In certain embodiments of the present invention, the crystallizing comprises:
first-stage crystallization is carried out under the conditions that the vacuum degree is 0.083-0.093 MPa and the temperature is 55-65 ℃;
performing secondary crystallization at a vacuum degree of 0.090-0.096 MPa and a temperature of 42-49 ℃;
and then carrying out three-stage crystallization at a vacuum degree of 0.097-0.101 MPa and a temperature of 28-32 ℃.
The step-type crystallization can increase the grain size of the crystal, or the grain size of the crystal can be controlled.
In certain embodiments of the invention, the primary crystallization is at a pressure of 0.084MPa or 0.088MPa and at a temperature of 64 ℃ or 55 ℃; the pressure of the secondary crystallization is 0.090MPa or 0.096MPa, and the temperature is 42 ℃; the pressure of the third-stage crystallization is 0.097MPa or 0.101MPa, and the temperature is 32 ℃ or 28 ℃.
In certain embodiments of the invention, the crystallization is performed in a crystallizer. In certain embodiments of the invention, the primary crystallization is performed in a primary crystallizer, the secondary crystallization is performed in a secondary crystallizer, and the tertiary crystallization is performed in a tertiary crystallizer.
In certain embodiments of the invention, the gas obtained from the first stage crystallization is subjected to a first stage condensation. In certain embodiments, the first stage condensation is performed using recycled water. In some embodiments, the temperature of the gas after the primary condensation is 30-45 ℃. And after the obtained condensate is collected in a condensate tank, conveying the condensate to a dilute methanol storage tank by using a pump, and discharging the non-condensable gas after the non-condensable gas is buffered by a primary vacuum buffer tank.
In certain embodiments of the invention, the gas obtained from the secondary crystallization is subjected to secondary condensation. In certain embodiments, the secondary condensation is performed using recycled water. In some embodiments, the gas temperature after the secondary condensation is 30-45 ℃. And after the obtained condensate is collected in a condensate tank, conveying the condensate to a dilute methanol storage tank by using a pump, and discharging the non-condensable gas after the non-condensable gas is buffered by a secondary vacuum buffer tank.
In certain embodiments of the invention, the gas resulting from the tertiary crystallization is subjected to tertiary condensation. In certain embodiments, the three-stage condensation is performed with recycled water. In some embodiments, the gas temperature after the three-stage condensation is 30-45 ℃. And after the obtained condensate is collected in a condensate tank, conveying the condensate to a dilute methanol storage tank by using a pump, and discharging the non-condensable gas after the non-condensable gas is buffered by a secondary vacuum buffer tank.
In some embodiments of the present invention, after the third-stage crystallization, centrifugal drying is further included to obtain glyphosate. In certain embodiments of the present invention, the centrifugal drying is performed in a centrifugal drying apparatus.
In some embodiments of the invention, the condensation of the gas after the secondary hydrolysis reaction is a vacuum cooling at a pressure of not less than-70 KPa; or the condensation is water adding and cooling, and the temperature after water adding and cooling is 30-90 ℃. In certain embodiments of the present invention, the vacuum ramping pressure is-60 KPa. In certain embodiments of the invention, the condensation is carried out in a hydrolysis tail gas condenser. In some embodiments of the invention, the condensed condensate may be collected to a dilute methanol buffer tank.
Mixing the gas generated by the primary hydrolysis reaction, the non-condensable gas and alkali liquor, and carrying out neutralization reaction. In certain embodiments of the present invention, the gas generated by the acidification, the gas generated by the primary hydrolysis reaction, the non-condensable gas and the alkali liquor are mixed to perform a neutralization reaction. In certain embodiments of the invention, the lye comprises a sodium hydroxide solution. In certain embodiments of the present invention, the concentration of the lye by mass is not higher than 48%, preferably not higher than 10%, more preferably not higher than 5%. In certain embodiments of the invention, the gas produced by the primary hydrolysis reaction comprises methanol, methylal, methyl chloride, water, and hydrogen chloride. In certain embodiments of the invention, the non-condensable gas comprises methanol, methylal, methyl chloride, water and hydrogen chloride.
In some embodiments of the invention, the temperature of the neutralization reaction is 70-90 ℃ and the pressure is-5-10 KPa. In certain embodiments of the invention, the temperature of the neutralization reaction is 74 ℃ or 85 ℃ and the pressure is 0KPa or 5 KPa.
In certain embodiments of the invention, the neutralization is performed in a caustic tower.
After the neutralization reaction is completed, the solution after the neutralization reaction is mixed with condensate (the condensate here refers to condensate obtained by condensing gas after the secondary hydrolysis reaction), and then steam stripping is carried out. In certain embodiments of the invention, the mixing is performed in a second mixing device. In some embodiments of the invention, the temperature of the stripping tower kettle is 100-108 ℃, and the stripping pressure is-5-30 KPa. In some embodiments of the invention, the temperature of the stripping tower kettle is 100-105 ℃, 103 ℃ or 100 ℃, and the stripping pressure is 0-10 KPa, 5KPa or 10 KPa. In certain embodiments of the invention, the stripping is performed in a stripper.
In certain embodiments of the invention, the stripped wastewater may enter a wastewater treatment plant.
In the invention, the gas obtained by steam stripping and the gas obtained by neutralization reaction are subjected to first rectification at-10 to 10KPa and the temperature of a tower kettle is 65 to 85 ℃. In certain embodiments of the invention, the stripped gas comprises methanol and water. In certain embodiments of the invention, the pressure of the first rectification is 5KPa or 10KPa and the temperature is 65 ℃. In some embodiments of the invention, the reflux ratio of the first rectification is 1-4: 1. in certain embodiments, the reflux ratio of the first rectification is 2.2 to 2.3: 1 or 2.2: 1. in certain embodiments of the invention, the first rectification is performed in a separation column. In certain embodiments of the invention, the gas from the first rectification comprises methanol, methylal, and methyl chloride.
In the invention, the tower bottom liquid obtained by the second rectification is subjected to second rectification at the temperature of 85-170 ℃ and under the pressure of 0.1-0.8 MPa to obtain the methanol. In certain embodiments of the invention, the pressure of the second rectification is 0.5MPa and the still temperature of the second rectification is 150 ℃. In some embodiments of the invention, the reflux ratio of the second rectification is 1-4: 1. in certain embodiments, the reflux ratio of the second rectification is 1.5: 1. in certain embodiments of the invention, the second rectification is performed in a methanol column.
In certain embodiments of the invention, the second rectification comprises low pressure methanol rectification and high pressure methanol rectification. In some embodiments of the invention, the pressure of the low-pressure methanol rectification is 0.1-0.3 MPa, the temperature of a tower kettle is 85-120 ℃, and the reflux ratio is 1-4: 1 or 1.5: 1. in certain embodiments, the pressure of the low-pressure methanol rectification is 0.18MPa or 0.1MPa, the temperature of a tower kettle is 107 ℃ or 115 ℃, and the reflux ratio is 1.5-2: 1 or 1.5: 1. in certain embodiments of the invention, the low pressure methanol rectification is performed in a low pressure methanol column. A part of methanol can be recovered through low-pressure methanol rectification.
In some embodiments of the invention, the pressure of the high-pressure methanol rectification is 0.4-0.8 MPa, the temperature of a tower kettle is 135-170 ℃, and the reflux ratio is 1-4: 1. in certain embodiments of the invention, the pressure of the high-pressure methanol rectification is 0.6MPa or 0.7MPa, the temperature of a tower kettle is 150-165 ℃ or 155 ℃, and the reflux ratio is 2-2.5: 1 or 2.5: 1. in certain embodiments of the invention, the high pressure methanol rectification is performed in a high pressure methanol column. In certain embodiments of the invention, the liquid after the high pressure methanol rectification is refluxed to the stripper. Most of the methanol can be recovered by high-pressure methanol rectification.
In the invention, the tower top low-boiling-point substance obtained by the first rectification is subjected to third rectification at the temperature of 0-80 KPa, the tower kettle temperature of 55-70 ℃ and the tower top temperature of-10-20 ℃ to obtain methyl chloride. In some embodiments of the invention, the pressure of the third rectification is 55KPa or 40KPa, the temperature of the tower kettle is 60-65 ℃, the temperature of the tower top is-14-17 ℃, and-14 ℃ or-17 ℃. In some embodiments of the invention, the reflux ratio of the third rectification is 1-3.5: 1. in certain embodiments, the reflux ratio of the third rectification is 1.2 to 1.5: 1 or 1.5: 1. in certain embodiments of the invention, the third rectification is performed in a demethanizer.
And performing fourth rectification on the tower bottom liquid obtained by the third rectification at the temperature of 65-85 ℃ at 0-30 KPa to obtain methylal and methanol. In certain embodiments of the invention, the pressure of the fourth rectification is 20KPa or 10KPa and the column bottom temperature is 73 ℃ or 80 ℃. In some embodiments of the invention, the reflux ratio of the fourth rectification is 0.5-2: 1. in certain embodiments, the fourth rectification has a reflux ratio of 1: 1. in certain embodiments of the invention, the fourth rectification is performed in a formal column.
The source of the above-mentioned raw materials is not particularly limited in the present invention, and may be generally commercially available.
The continuous synthesis method of glyphosate provided by the invention has the advantages of simple process and high glyphosate yield, and can effectively recover byproducts.
The invention also provides a continuous synthesis system of glyphosate for implementing the continuous synthesis method, which comprises the following steps:
a synthesis kettle;
the first mixing device is connected with a synthetic liquid outlet of the synthetic kettle;
the first-stage hydrolysis reaction device is connected with the acidizing fluid outlet of the first mixing device;
the second-stage hydrolysis reaction device is connected with a product solution outlet of the first-stage hydrolysis reaction device;
the crystallizer is connected with a slurry outlet of the secondary hydrolysis reaction device;
the hydrolysis tail gas condenser is connected with a gas outlet of the secondary hydrolysis reaction device;
the first gas inlet is connected with the gas outlet of the hydrolysis tail gas condenser; a second gas inlet of the alkaline tower is connected with a gas outlet of the first mixing device; a third gas inlet of the alkaline tower is connected with a gas outlet of the primary hydrolysis reaction device;
the first liquid inlet is connected with the liquid outlet of the alkaline tower; a second liquid inlet of the second mixing device is connected with a liquid outlet of the hydrolysis tail gas condenser;
a stripper having a first liquid inlet coupled to the liquid outlet of the second mixing device;
the first gas inlet is connected with the gas outlet of the alkaline washing tower; the second gas inlet of the separation tower is connected with the gas outlet of the stripping tower;
a methanol column connected to the liquid outlet of the separation column;
a methane-removing column connected to the gas outlet of the separation column;
and the formaldehyde condensation tower is connected with a liquid outlet of the methane-removing tower.
See fig. 1. FIG. 1 is a schematic flow diagram of a continuous synthesis system for glyphosate, according to an embodiment of the present invention.
The continuous synthesis system of glyphosate provided by the invention comprises a synthesis kettle. The synthesis kettle is used for the reaction of the step A) in the continuous synthesis method. In an embodiment of the invention, the synthesis kettle is provided with a raw material inlet and a synthesis liquid outlet. The structure of the synthesis kettle is not particularly limited, and the synthesis kettle can be a conventional synthesis kettle. And discharging the synthetic liquid obtained after the reaction from a synthetic liquid outlet of the synthesis kettle and allowing the synthetic liquid to enter the first mixing device. In certain embodiments of the present invention, the synthesis liquid discharged from the synthesis liquid outlet of the synthesis tank enters the first mixing device through a synthesis liquid delivery pump. The structure of the synthetic liquid delivery pump is not particularly limited, and the synthetic liquid delivery pump can be a conventional centrifugal pump.
The continuous synthesis system of glyphosate provided by the invention also comprises a first mixing device connected with the synthesis liquid outlet of the synthesis kettle. In certain embodiments of the invention, the first mixing device is provided with a mixed liquor inlet, an acidulant outlet, and a gas outlet. In certain embodiments of the invention, the mixed liquor inlet of the first mixing device is connected to the mixed liquor outlet of the synthesis vessel. The first mixing device is used for acidifying the synthetic fluid. In some embodiments of the invention, the first mixing device is a tubular static mixer, of type SK, SV or SX, preferably SK.
The continuous synthesis system of glyphosate provided by the invention also comprises a first-stage hydrolysis reaction device connected with the acidification liquid outlet of the first mixing device. The first-stage hydrolysis reaction device is used for first-stage hydrolysis of the acidizing fluid and simultaneously separating light components such as methanol, methylal, methyl chloride and the like from the hydrolysis fluid. In certain embodiments of the present invention, the first hydrolysis reaction device comprises a first hydrolysis reaction tower and a first hydrolysis reaction kettle.
In certain embodiments of the present invention, the first stage hydrolysis reaction tower is provided with an acidified liquid inlet, a product solution outlet, a gas outlet and a gas inlet. And an acidizing fluid inlet of the first-stage hydrolysis reaction tower is connected with an acidizing fluid outlet of the first mixing device.
In certain embodiments of the present invention, the first stage hydrolysis reactor is provided with a product solution inlet, a product solution outlet and a gas outlet. And a product solution inlet of the first-stage hydrolysis reaction tower is connected with an acidizing fluid outlet of the first mixing device. And a product solution outlet of the primary hydrolysis reaction tower is connected with a product solution inlet of the primary hydrolysis reaction kettle. And a gas outlet of the primary hydrolysis reaction kettle is connected with a gas inlet of the primary hydrolysis reaction tower. And returning the gas discharged from the first-stage hydrolysis reaction kettle to the first-stage hydrolysis reaction tower.
The structures of the first-stage hydrolysis reaction tower and the first-stage hydrolysis reaction kettle are not particularly limited. In certain embodiments of the invention, the first hydrolysis reaction column is a corrosion-resistant packed column. In certain embodiments, the first stage hydrolysis reaction tower is an open glass lined packed tower, a tetrafluoro-lined packed tower, or a graphite packed tower. In certain embodiments of the present invention, the first hydrolysis reactor is an open glass lined reactor.
In certain embodiments of the present invention, the continuous synthesis system further comprises a hydrolysis reboiler. The hydrolysis reboiler is used for heating the first-stage hydrolysis reaction kettle. The connection mode of the hydrolysis reboiler is not particularly limited, and the first-stage hydrolysis reaction kettle can be heated. The structure of the hydrolysis reboiler is not particularly limited in the present invention, and in some embodiments of the present invention, the hydrolysis reboiler is a round block and hole graphite heat exchanger.
In certain embodiments of the present invention, the continuous synthesis system further comprises an acidification cooler. See fig. 2. FIG. 2 is a schematic flow diagram of a continuous synthesis system for glyphosate according to another embodiment of the present invention. The acidification cooler is used for cooling the acidification liquid. And an acidizing fluid inlet of the acidizing cooler is connected with an acidizing fluid outlet of the first mixing device, and an acidizing fluid outlet of the acidizing cooler is connected with an acidizing fluid inlet of the first-stage hydrolysis reaction tower. The structure of the acidification liquid cooler is not particularly limited, and the acidification liquid cooler can be a conventional acidification liquid cooler. In certain embodiments of the invention, the acidified liquid discharged from the acidified liquid outlet of the first mixing apparatus is passed by an acidified liquid pump into an acidified chiller. The structure of the acidizing fluid pump is not particularly limited, and the acidizing fluid pump can be a conventional centrifugal pump or a magnetic pump.
The continuous synthesis system of glyphosate provided by the invention also comprises a secondary hydrolysis reaction device connected with a product solution outlet of the primary hydrolysis reaction device. The secondary hydrolysis reaction device is used for carrying out secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction, and simultaneously separating residual light components, water, hydrogen chloride and the like. In certain embodiments of the present invention, the secondary hydrolysis reaction device is a secondary hydrolysis reaction kettle.
In certain embodiments of the invention, the secondary hydrolysis reactor is provided with a product solution inlet, a slurry outlet and a gas outlet. And a product solution inlet of the second-stage hydrolysis reaction kettle is connected with a product solution outlet of the first-stage hydrolysis reaction kettle.
The structure of the secondary hydrolysis reactor is not particularly limited, and in certain embodiments of the invention, the secondary hydrolysis reactor is an open glass-lined reactor.
The continuous synthesis system of glyphosate provided by the invention also comprises a crystallizer connected with the slurry outlet of the secondary hydrolysis reaction device. The crystallizer is used for separating glyphosate crystals from the slurry discharged by the secondary hydrolysis reaction device. In certain embodiments of the present invention, the continuous synthesis system further comprises a surge tank. The buffer tank is used for adjusting the pH value of the slurry discharged from the slurry outlet of the secondary hydrolysis reaction device and then enters the crystallizer. In certain embodiments of the present invention, the slurry inlet of the surge tank is connected to the slurry outlet of the secondary hydrolysis reaction device.
In certain embodiments of the present invention, the crystallizer comprises a primary crystallizer, a secondary crystallizer, and a tertiary crystallizer.
In certain embodiments of the present invention, the slurry inlet of the primary crystallizer is connected to the slurry outlet of the secondary hydrolysis reactor. And the slurry inlet of the secondary crystallizer is connected with the slurry outlet of the primary crystallizer. And the slurry inlet of the third-stage crystallizer is connected with the slurry outlet of the second-stage crystallizer. And the slurry discharged from the slurry outlet of the third-stage crystallizer is the glyphosate. In certain embodiments, the slurry inlet of the primary crystallizer is connected to the liquid outlet of the surge tank.
The present invention is not limited to the structure of each crystallizer, and in some embodiments of the present invention, each crystallizer may be a DTB crystallizer.
In certain embodiments of the invention, the slurry exiting the secondary hydrolysis reaction tower is fed to the primary crystallizer via a primary crystallization feed pump. The structure of the primary crystallization feed pump is not particularly limited, and the primary crystallization feed pump can be a conventional centrifugal pump or a magnetic pump. In certain embodiments of the invention, the slurry discharged from the primary crystallizer is fed to the secondary crystallizer by a secondary crystallization feed pump. The structure of the secondary crystallization feed pump is not particularly limited in the invention, and the secondary crystallization feed pump can be a conventional centrifugal pump or a magnetic pump. In certain embodiments of the invention, the slurry discharged from the secondary crystallizer is fed to the tertiary crystallizer by a tertiary crystallization feed pump. The structure of the three-stage crystallization feed pump is not particularly limited, and the three-stage crystallization feed pump can be a conventional centrifugal pump or a magnetic pump.
In certain embodiments of the present invention, the continuous synthesis system further comprises a primary condenser, a primary vacuum surge tank, and a condensate tank. In some embodiments of the present invention, the gas inlet of the primary condenser is connected to the gas outlet of the primary crystallizer, and the liquid outlet of the primary condenser is connected to the first liquid inlet of the condensate tank. And the gas outlet of the primary condenser is connected with the gas inlet of the primary vacuum buffer tank. And condensing the gas discharged from the primary crystallizer in a primary condenser, feeding the condensate into a condensate tank, and discharging the non-condensable gas after the non-condensable gas is buffered by a primary vacuum buffer tank. The structure of the primary condenser, the primary vacuum buffer tank and the condensate tank is not particularly limited, and the primary condenser, the primary vacuum buffer tank and the condensate tank can be conventional condensers, vacuum buffer tanks and condensate tanks.
In certain embodiments of the present invention, the continuous synthesis system further comprises a secondary condenser and a secondary vacuum surge tank. In some embodiments of the present invention, a gas inlet of the secondary condenser is connected to a gas outlet of the secondary crystallizer, a liquid outlet of the secondary condenser is connected to the second liquid inlet of the condensate tank, and a gas outlet of the secondary condenser is connected to a gas inlet of the secondary vacuum buffer tank. And condensing the gas discharged from the secondary crystallizer in a secondary condenser, feeding the condensate into a condensate tank, and discharging the non-condensable gas after the non-condensable gas is buffered by a secondary vacuum buffer tank. The structure of the secondary condenser and the secondary vacuum buffer tank is not particularly limited, and the secondary condenser and the secondary vacuum buffer tank can be a conventional condenser, a conventional vacuum buffer tank and a conventional condensate tank.
In certain embodiments of the present invention, the continuous synthesis system further comprises a three-stage condenser and a three-stage vacuum surge tank. In some embodiments of the present invention, a gas inlet of the third-stage condenser is connected to a gas outlet of the third-stage crystallizer, a liquid outlet of the third-stage condenser is connected to a third liquid inlet of the condensate tank, and a gas outlet of the third-stage condenser is connected to a gas inlet of the third-stage vacuum buffer tank. And condensing the gas discharged from the three-stage crystallizer in a three-stage condenser, feeding the condensate into a condensate tank, and discharging the non-condensable gas after the non-condensable gas is buffered by a three-stage vacuum buffer tank. The structure of the three-stage condenser and the three-stage vacuum buffer tank is not particularly limited, and the three-stage condenser and the three-stage vacuum buffer tank can be a conventional condenser, a conventional vacuum buffer tank and a conventional condensate tank.
In some embodiments of the present invention, after the liquid entering the condensate tank is cooled in the condensate tank, the cooled liquid may be pumped to a dilute methanol storage tank and may be returned to the three crystallizers.
In some embodiments of the present invention, the continuous synthesis system of glyphosate further comprises a centrifugal drying device. And the inlet of the centrifugal drying device is connected with the glyphosate outlet of the third-stage crystallizer. And the centrifugal drying device is used for drying the glyphosate obtained by the three-stage crystallizer. The structure of the centrifugal drying device is not limited in the present invention, and a centrifugal drying device known to those skilled in the art may be used.
The continuous synthesis system of glyphosate provided by the invention also comprises a hydrolysis tail gas condenser connected with the gas outlet of the secondary hydrolysis reaction device. And the hydrolysis tail gas condenser is used for cooling tail gas after the secondary hydrolysis reaction. In certain embodiments of the invention, the hydrolysis tail gas condenser is provided with a gas inlet, a gas outlet and a condensate outlet. In certain embodiments of the present invention, the gas inlet of the hydrolysis tail gas condenser is connected to the gas outlet of the secondary hydrolysis reaction device. In certain embodiments, the gas inlet of the hydrolysis tail gas condenser is connected with the gas outlet of the secondary hydrolysis reaction kettle. The present invention is not particularly limited in its structure, and in some embodiments, the hydrolysis offgas condenser may be an acid-proof heat exchanger.
The continuous synthesis system of glyphosate also comprises a caustic washing tower. The hydrolysis tail gas is acid gas, and the acid and alkali in the alkaline washing tower neutralize the acid and alkali, so that the range of equipment material selection of the rear system is wide, and the cost is lower. The alkaline tower is provided with a first gas inlet, a second gas inlet, a third gas inlet, a liquid outlet and a gas outlet. In certain embodiments of the invention, the first gas inlet of the alkaline tower is connected with the gas outlet of the hydrolysis tail gas condenser, the second gas inlet of the alkaline tower is connected with the gas outlet of the first mixing device, and the third gas inlet of the alkaline tower is connected with the gas outlet of the primary hydrolysis reaction device. In certain embodiments of the invention, the third gas inlet of the caustic tower is connected to the gas outlet of the primary hydrolysis reaction tower. The structure of the caustic tower is not particularly limited in the present invention, and in certain embodiments of the present invention, the caustic tower may be a packed tower.
The continuous synthesis system for glyphosate further comprises a second mixing device connected with the liquid outlet of the alkaline washing tower. In an embodiment of the invention, the second mixing device is provided with a first liquid inlet, a second liquid inlet and a liquid outlet. And a first liquid inlet of the second mixing device is connected with a liquid outlet of the alkaline washing tower. And a second liquid inlet of the second mixing device is connected with a liquid outlet of the hydrolysis tail gas condenser. In some embodiments of the invention, the second mixing device is a tubular static mixer, of type SK, SV or SX, preferably SK.
The continuous synthesis system of the glyphosate further comprises a stripping tower connected with the liquid outlet of the second mixing device. The stripping tower extracts low components in the feed in a stripping mode, reduces raw material consumption and improves product yield. In certain embodiments of the present invention, the stripper is provided with a first liquid inlet, a second liquid inlet, a gas outlet, and a liquid outlet. And a first liquid inlet of the stripping tower is connected with a liquid outlet of the second mixing device. In certain embodiments of the invention, the second liquid inlet of the stripper column is connected to the liquid outlet of the high pressure methanol column. The structure of the stripping tower is not particularly limited in the present invention, and the stripping tower may be a conventional stripping tower.
The continuous synthesis system of the glyphosate further comprises a separation tower connected with a gas outlet of the alkaline washing tower. The separation tower is used for carrying out the first rectification, and the tower kettle diluted methanol and the tower top low-boiling-point substance can be obtained through the first rectification. In certain embodiments of the invention, the separation column is provided with a first gas inlet, a second gas inlet, a liquid outlet, and a gas outlet. In certain embodiments of the invention, the first gas inlet of the separation column is connected to the gas outlet of the caustic tower and the second gas inlet of the separation column is connected to the gas outlet of the stripper. The present invention is not particularly limited in its structure, and in certain embodiments of the present invention, the separation column may be a conventional packed rectification column.
The continuous synthesis system of glyphosate further comprises a methanol tower connected with the liquid outlet of the separation tower. And the dilute methanol in the tower kettle in the separation tower is discharged from a liquid outlet of the separation tower and enters a methanol tower. In certain embodiments of the invention, the methanol column is provided with a liquid inlet and a liquid outlet. And the liquid inlet of the methanol tower is connected with the liquid outlet of the separation tower. The present invention is not particularly limited as to the structure of the methanol column, which may be a conventional packed rectification column in some embodiments of the invention.
In certain embodiments of the invention, the methanol column comprises a low pressure methanol column and a high pressure methanol column. The low-pressure methanol tower is provided with a liquid inlet, a liquid outlet and a methanol outlet. The high-pressure methanol tower is provided with a liquid inlet, a liquid outlet and a methanol outlet. The liquid inlet of the low-pressure methanol tower is connected with the liquid outlet of the separation tower; and the liquid inlet of the high-pressure methanol tower is connected with the liquid outlet of the low-pressure methanol tower. And a liquid outlet of the high-pressure methanol tower is connected with a second liquid phase inlet of the stripping tower. The present invention is not particularly limited with respect to the structure of the low pressure methanol column and the high pressure methanol column, and in some embodiments of the present invention, the low pressure methanol column may be a conventional packed rectification column. In certain embodiments of the invention, the high pressure methanol column may be a conventional packed rectification column.
The continuous synthesis system of glyphosate provided by the invention also comprises a methane-removing tower connected with the gas outlet of the separation tower. The chloromethane is refined by rectification of a chloromethane removing tower, so that the post-system treatment cost is reduced, and simultaneously, the methanol and methylal are recovered, and the consumption of the methanol is reduced. In certain embodiments of the invention, the de-chloromethane tower is provided with a gas inlet, a bottoms outlet, and a chloromethane outlet. In certain embodiments of the invention, the gas inlet of the de-chloromethane column is connected to the gas outlet of the separation column. The present invention is not particularly limited in terms of the structure of the demethanizer, and in some embodiments of the present invention, the demethanizer may be a conventional packed rectification column.
The continuous synthesis system of the glyphosate further comprises a formaldehyde condensation tower connected with a liquid outlet of the methane-removing tower. The methylal tower is used for recovering methylal and methanol. The formaldehyde column is provided with a liquid inlet and a gas outlet. And a liquid inlet of the formaldehyde condensation tower is connected with a tower bottom liquid outlet of the methane-removing tower. The present invention is not particularly limited in its structure, and in certain embodiments of the present invention, the formaldehyde column may be a conventional packed rectification column.
The continuous synthesis method and the system for glyphosate provided by the invention have the advantages of simple process, high glyphosate yield and capability of effectively recovering byproducts.
For further illustration of the present invention, the following examples are provided to describe the continuous synthesis method and system of glyphosate in detail, but they should not be construed as limiting the scope of the present invention.
The starting materials used in the following examples are all generally commercially available.
Example 1
Experiments were performed on a continuous synthesis system for glyphosate as described in figure 2:
synthesizing glyphosate synthetic solution in a synthesis kettle:
the raw materials comprise: 5200 parts by weight of methanol, 1630 parts by weight of triethylamine, 950 parts by weight of paraformaldehyde, 1200 parts by weight of glycine and 2060 parts by weight of dimethyl phosphite.
a1) Carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 45 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at 50 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at 50 ℃ to obtain synthetic liquid.
The synthesis solution and hydrochloric acid were mixed in a first mixing device (static mixer) and acidified at 50 ℃ under a pressure of 0 KPa. After the acidification was complete, it was cooled to 40 ℃ in an acidification cooler. And (3) feeding the cooled acidified liquid into a first-stage hydrolysis reaction tower and a first-stage hydrolysis kettle to perform a first-stage hydrolysis reaction, wherein the temperature of the first-stage hydrolysis reaction is 108 ℃, and the pressure is 10 KPa. And performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction in a secondary hydrolysis kettle, wherein the temperature of the secondary hydrolysis reaction is 120 ℃, and the pressure is-5 KPa.
And (3) adjusting the pH value of the slurry after the secondary hydrolysis reaction to 0.1 in a buffer tank, feeding the slurry into a primary crystallizer, performing primary crystallization at the vacuum degree of 0.084MPa and the temperature of 64 ℃, feeding the slurry after the primary crystallization into a secondary crystallizer, performing secondary crystallization at the vacuum degree of 0.090MPa and the temperature of 49 ℃, feeding the slurry after the secondary crystallization into a tertiary crystallizer, performing tertiary crystallization at the vacuum degree of 0.097MPa and the temperature of 32 ℃, and centrifugally drying a product after the tertiary crystallization to obtain the glyphosate. The detection proves that the yield of the glyphosate is 74 percent, and the purity is 97 percent. And condensing the gas obtained by crystallization at each stage to 40 ℃ by using circulating water, collecting the obtained condensate to a condensate tank, conveying the condensate to a dilute methanol storage tank by using a pump, and discharging the non-condensable gas after the non-condensable gas is buffered by a first-stage vacuum buffer tank.
And (3) carrying out vacuum cooling on the gas after the secondary hydrolysis reaction in a hydrolysis tail gas condenser, wherein the pressure of the vacuum cooling is-60 KPa. And (2) gas (comprising methanol, methylal, methyl chloride, water and hydrogen chloride) discharged from the hydrolysis tail gas condenser, gas (comprising methanol, methylal, methyl chloride, water and hydrogen chloride) discharged from the primary hydrolysis reaction tower and gas discharged from the static mixer enter an alkaline tower, and are subjected to neutralization reaction with a sodium hydroxide solution with the mass concentration of 5% in the alkaline tower, wherein the temperature of the neutralization reaction is 74 ℃ and the pressure is 0 KPa.
Mixing the solution after the neutralization reaction with condensate (the condensate here refers to condensate obtained by condensing gas after the secondary hydrolysis reaction), and then carrying out steam stripping in a stripping tower, wherein the temperature of a tower kettle of the steam stripping is 103 ℃, and the pressure of the steam stripping is 5 KPa. And (2) introducing gas (comprising methanol and water) separated from the top of the stripping tower and gas discharged from the top of the alkaline washing tower into a separation tower for first rectification separation, wherein the tower kettle temperature of the separation tower is 76 ℃, the tower top pressure is 5KPa, and the tower top reflux ratio of the separation tower is 2.2: and 1, enabling the wastewater at the bottom of the stripping tower to enter a wastewater treatment device.
And (2) introducing gas (comprising methanol, methylal and methyl chloride) evaporated from the top of the separation tower into a methane-dechlorinating tower, recovering the methyl chloride, wherein the temperature at the top of the methane-dechlorinating tower is-14 ℃, the pressure at the top of the methane-dechlorinating tower is 55KPa, and the reflux ratio is 1.5: 1; and (3) enabling tower bottom liquid of the methane-removing tower to enter a methylal tower, recovering methylal, wherein the tower bottom temperature of the methylal tower is 73 ℃, the pressure is 20KPa, and the reflux ratio is 1: 1.
the tower bottom components of the separation tower sequentially enter a low-pressure methanol tower and a high-pressure methanol tower to recover methanol, the pressure of the low-pressure methanol tower is 0.18MPa, the temperature of a tower kettle is 107 ℃, and the reflux ratio is 1.5: 1, the pressure of a high-pressure methanol tower is 0.6MPa, the temperature of a tower kettle is 155 ℃, and the reflux ratio is 2.5: 1. and liquid rectified by the high-pressure methanol tower flows back to the stripping tower.
The detection shows that the recovery rate of the chloromethane is more than 99 percent, the purity (without air) is about 97.5 percent, and the dimethyl ether is about 2.5 percent; the recovery rate of methylal is more than 99 percent, and the purity is more than 85 percent; the recovery rate of the methanol is more than 99 percent, and the purity is more than 99.5 percent; the methanol consumption of each ton of glyphosate is 260kg, the steam consumption of each ton of glyphosate is 5.6t, and the sulfuric acid consumption of each ton of chloromethane is 55 kg.
Example 2
Experiments were performed on a continuous synthesis system for glyphosate as described in figure 2:
synthesizing glyphosate synthetic solution in a synthesis kettle:
the raw materials comprise: 5400 parts by weight of methanol, 1650 parts by weight of triethylamine, 950 parts by weight of paraformaldehyde, 1250 parts by weight of glycine and 2100 parts by weight of dimethyl phosphite.
a1) Carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 50 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at the temperature of 45 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at the temperature of 45 ℃ to obtain synthetic liquid.
The synthesis solution and hydrochloric acid were mixed in a first mixing device (static mixer) and acidified at 40 ℃ under a pressure of 5 KPa. After acidification was complete, it was cooled to 30 ℃ in an acidification cooler. And (3) feeding the cooled acidified liquid into a first-stage hydrolysis reaction tower and a first-stage hydrolysis kettle to perform a first-stage hydrolysis reaction, wherein the temperature of the first-stage hydrolysis reaction is 100 ℃, and the pressure is 5 KPa. And performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction in a secondary hydrolysis kettle, wherein the temperature of the secondary hydrolysis reaction is 115 ℃, and the pressure is-5 KPa.
And (3) adjusting the pH value of the slurry after the secondary hydrolysis reaction to 2 in a buffer tank, feeding the slurry into a primary crystallizer, performing primary crystallization at the vacuum degree of 0.088MPa and the temperature of 55 ℃, feeding the slurry after the primary crystallization into a secondary crystallizer, performing secondary crystallization at the vacuum degree of 0.096MPa and the temperature of 42 ℃, feeding the slurry after the secondary crystallization into a tertiary crystallizer, performing tertiary crystallization at the vacuum degree of 0.101MPa and the temperature of 28 ℃, and centrifugally drying a product after the tertiary crystallization to obtain the glyphosate. The detection proves that the yield of the glyphosate is 76%, and the purity is 95%. And condensing the gas obtained by crystallization at each stage to 40 ℃ by using circulating water, collecting the obtained condensate to a condensate tank, conveying the condensate to a dilute methanol storage tank by using a pump, and discharging the non-condensable gas after the non-condensable gas is buffered by a first-stage vacuum buffer tank.
And (3) carrying out vacuum cooling on the gas after the secondary hydrolysis reaction in a hydrolysis tail gas condenser, wherein the pressure of the vacuum cooling is-60 KPa. And (2) gas (comprising methanol, methylal, methyl chloride, water and hydrogen chloride) discharged from the hydrolysis tail gas condenser, gas (comprising methanol, methylal, methyl chloride, water and hydrogen chloride) discharged from the primary hydrolysis reaction tower and gas discharged from the static mixer enter an alkaline tower, and are subjected to neutralization reaction with a sodium hydroxide solution with the mass concentration of 5% in the alkaline tower, wherein the temperature of the neutralization reaction is 85 ℃, and the pressure is 5 KPa.
Mixing the solution after the neutralization reaction with condensate (the condensate here refers to condensate obtained by condensing gas after the secondary hydrolysis reaction), and then carrying out steam stripping in a stripping tower, wherein the temperature of a tower kettle of the steam stripping is 100 ℃, and the pressure of the steam stripping is 10 KPa. And (2) introducing gas (comprising methanol and water) separated from the top of the stripping tower and gas discharged from the top of the alkaline washing tower into a separation tower for first rectification separation, wherein the tower kettle temperature of the separation tower is 65 ℃, the tower top pressure is 10KPa, and the tower top reflux ratio of the separation tower is 2.2: and 1, enabling the wastewater at the bottom of the stripping tower to enter a wastewater treatment device.
And (2) introducing gas (comprising methanol, methylal and methyl chloride) evaporated from the top of the separation tower into a methane-dechlorinating tower, recovering the methyl chloride, wherein the temperature at the top of the methane-dechlorinating tower is-17 ℃, the pressure at the top of the methane-dechlorinating tower is 40KPa, and the reflux ratio is 1.5: 1; and (3) enabling tower bottom liquid of the methane-removing tower to enter a methylal tower, recovering methylal, wherein the tower bottom temperature of the methylal tower is 80 ℃, the pressure is 10KPa, and the reflux ratio is 1: 1.
the tower bottom components of the separation tower sequentially enter a low-pressure methanol tower and a high-pressure methanol tower to recover methanol, the pressure of the low-pressure methanol tower is 0.1MPa, the temperature of a tower kettle is 115 ℃, and the reflux ratio is 1.5: 1, the pressure of a high-pressure methanol tower is 0.7MPa, the temperature of a tower kettle is 155 ℃, and the reflux ratio is 2.5: 1. and liquid rectified by the high-pressure methanol tower flows back to the stripping tower.
The detection shows that the recovery rate of the chloromethane is more than 99 percent, the purity (without air) is about 97.5 percent, and the dimethyl ether is about 2.5 percent; the recovery rate of methylal is more than 99 percent, and the purity is more than 85 percent; the recovery rate of the methanol is more than 99 percent, and the purity is more than 99.5 percent; 265kg of methanol is consumed by each ton of glyphosate, 5.5t of steam is consumed by each ton of glyphosate, and 55kg of sulfuric acid is consumed by each ton of methyl chloride.
Comparative example 1
Synthesizing glyphosate synthetic solution in a synthesis kettle:
the raw materials comprise: 5200 parts by weight of methanol, 1630 parts by weight of triethylamine, 950 parts by weight of paraformaldehyde, 1200 parts by weight of glycine and 2060 parts by weight of dimethyl phosphite.
a1) Carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 45 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at 50 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at 50 ℃ to obtain synthetic liquid.
The synthetic liquid and the hydrochloric acid are respectively metered in a metering tank, then are successively put into a hydrolysis kettle, the stirring is started, the temperature is slowly raised, the hydrolysis reaction (batch reaction) is carried out, the gas phase generated by the reaction is condensed through a first-stage, a second-stage and a third-stage, the condensate is collected into a dilute methanol tank, and the non-condensable gas (crude chloromethane) is conveyed to a chloromethane recovery device by a fan. The temperature of the hydrolysis reaction end point is controlled to be 110-135 ℃, and the system pressure is controlled to be 5-5 KPa.
After carrying out neutralization reaction on dilute methanol and liquid caustic soda with the mass concentration of 40% in a static mixer, preheating to 60-80 ℃ by using recovered methanol and steam condensate water, rectifying in a partition wall tower through gas-liquid two phases, controlling the temperature of the top of the methylal side tower at 42 ℃, controlling the pressure at normal pressure, controlling the reflux ratio at 5, condensing the gas phase extracted from the top of the tower to obtain a methylal product, and removing chloromethane from non-condensable gas (crude chloromethane) by using a chloromethane recovery device; the temperature of the top of the methanol side tower is controlled at 64 ℃, the pressure is normal, the reflux ratio is 1.5, the methanol product is extracted from the top of the tower, and the mixture of methanol and water is extracted from the middle lower side of the tower to the high-pressure methanol tower; removing the tower kettle waste water to an environment-friendly station after heat exchange; the temperature at the top of the high-pressure methanol tower is controlled at 120 ℃, the pressure is controlled at 0.55MPa, the reflux ratio is 3.5, the gas phase at the top of the high-pressure methanol tower is used as a heat source for the partition wall tower, the condensate is a methanol product, and the waste water at the bottom of the tower is subjected to heat exchange and then is discharged to an environmental protection station.
The recovery rate of methanol is more than 98%, the purity is more than 99.5%, 330kg of methanol is consumed by each ton of glyphosate, 7.3t of steam is consumed by each ton of glyphosate, and 130kg of sulfuric acid is consumed by each ton of methyl chloride.
The results of comparing the mass of methyl chloride and methylal obtained in examples 1 to 2 with that obtained in comparative example 1 are shown in tables 1 and 2:
TABLE 1 comparison of the quality of methyl chloride obtained in examples 1-2 and comparative example 1
| Methyl chloride | Dimethyl ether | Methylal | Methanol | Water (W) | |
| Example 1 | 97.5 | 2.5 | Not detected out | Not detected out | Not detected out |
| Example 2 | 97.5 | 2.5 | Not detected out | Not detected out | Not detected out |
| Comparative example 1 | 93.3 | 2.5 | 2.5 | 1.5 | 0.2 |
TABLE 2 results of comparing the qualities of the formals obtained in examples 1 to 2 and comparative example 1
| Methyl chloride | Methylal | Methanol | Water (W) | |
| Example 1 | <0.1 | 85 | 14.8 | 0.1 |
| Example 2 | <0.1 | 86 | 13.8 | 0.1 |
| Comparative example 1 | ≈3 | 85 | 11.9 | 0.1 |
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A continuous synthesis method of glyphosate comprises the following steps:
A) reacting glycine, paraformaldehyde and dialkyl phosphite in methanol under the action of triethylamine, and acidifying the reacted synthetic liquid to obtain acidified liquid;
B) carrying out primary hydrolysis reaction on the acidizing fluid at 90-112 ℃ and under-5-20 KPa;
C) performing secondary hydrolysis reaction on the product solution of the primary hydrolysis reaction at 115-130 ℃ and-10 KPa, crystallizing slurry obtained after the secondary hydrolysis reaction to obtain glyphosate, and condensing gas obtained after the secondary hydrolysis reaction to obtain condensate and non-condensable gas;
mixing the gas generated by the primary hydrolysis reaction, the non-condensable gas and alkali liquor, and performing neutralization reaction;
D) mixing the solution after the neutralization reaction with the condensate, carrying out steam stripping, carrying out first rectification on the gas obtained by steam stripping and the gas obtained by the neutralization reaction at-10 KPa and the tower kettle temperature of 65-85 ℃, and carrying out second rectification on the tower kettle liquid obtained by the first rectification at 0.1-0.8 MPa and the tower kettle temperature of 85-170 ℃ to obtain methanol; performing third rectification on the tower top low-boiling-point substances obtained by the first rectification at the temperature of 0-80 KPa, the tower kettle temperature of 55-70 ℃ and the tower top temperature of-10-20 ℃ to obtain methyl chloride; and performing fourth rectification on the tower bottom liquid obtained by the third rectification at the temperature of 65-85 ℃ at 0-30 KPa to obtain methylal.
2. The continuous synthesis process according to claim 1, wherein in step a), the reaction comprises:
a1) carrying out depolymerization reaction on methanol, triethylamine and paraformaldehyde at 40-55 ℃;
a2) performing addition reaction on the product after the depolymerization reaction and glycine at the temperature of 40-55 ℃;
a3) and carrying out condensation reaction on the product after the addition reaction and dialkyl phosphite at the temperature of 40-55 ℃ to obtain synthetic liquid.
3. The continuous synthesis method according to claim 1, wherein in the step A), the acidification temperature is 35-55 ℃, and the acidification pressure is-10 KPa.
4. The continuous synthesis method according to claim 1, wherein in the step C), the pH value of the slurry after the secondary hydrolysis reaction is 0.1-3;
the crystallization comprises the following steps:
first-stage crystallization is carried out under the conditions that the vacuum degree is 0.083-0.093 MPa and the temperature is 55-65 ℃;
performing secondary crystallization at a vacuum degree of 0.090-0.096 MPa and a temperature of 42-49 ℃;
then carrying out three-stage crystallization at a vacuum degree of 0.097-0.101 MPa and a temperature of 28-32 ℃;
the condensation is vacuum cooling, and the pressure of the vacuum cooling is more than or equal to-70 KPa; or the condensation is water adding cooling or heat exchanger cooling, and the temperature after water adding cooling is 30-90 ℃.
5. The continuous synthesis method according to claim 1, wherein in the step C), the temperature of the neutralization reaction is 70-90 ℃ and the pressure is-5-10 KPa.
6. The continuous synthesis method according to claim 1, wherein in the step D), the temperature of the stripping tower kettle is 100-108 ℃, and the stripping pressure is-5-30 KPa;
the reflux ratio of the first rectification is 1-4: 1; the reflux ratio of the second rectification is 1-4: 1; the reflux ratio of the third rectification is 1-3.5: 1; the reflux ratio of the fourth rectification is 0.5-2: 1.
7. the continuous synthesis method according to claim 1, wherein in step D), the second rectification comprises low-pressure methanol rectification and high-pressure methanol rectification;
the pressure of the low-pressure methanol rectification is 0.1-0.3 MPa, the temperature of a tower kettle is 85-120 ℃, and the reflux ratio is 1-4: 1;
the pressure of the high-pressure methanol rectification is 0.4-0.8 MPa, the temperature of a tower kettle is 135-170 ℃, and the reflux ratio is 1-4: 1.
8. a continuous synthesis system for glyphosate, comprising:
a synthesis kettle;
the first mixing device is connected with a synthetic liquid outlet of the synthetic kettle;
the first-stage hydrolysis reaction device is connected with the acidizing fluid outlet of the first mixing device;
the second-stage hydrolysis reaction device is connected with a product solution outlet of the first-stage hydrolysis reaction device;
the crystallizer is connected with a slurry outlet of the secondary hydrolysis reaction device;
the hydrolysis tail gas condenser is connected with a gas outlet of the secondary hydrolysis reaction device;
the first gas inlet is connected with the gas outlet of the hydrolysis tail gas condenser; a second gas inlet of the alkaline tower is connected with a gas outlet of the first mixing device; a third gas inlet of the alkaline tower is connected with a gas outlet of the primary hydrolysis reaction device;
the first liquid inlet is connected with the liquid outlet of the alkaline tower; a second liquid inlet of the second mixing device is connected with a liquid outlet of the hydrolysis tail gas condenser;
a stripper having a first liquid inlet coupled to the liquid outlet of the second mixing device;
the first gas inlet is connected with the gas outlet of the alkaline washing tower; the second gas inlet of the separation tower is connected with the gas outlet of the stripping tower;
a methanol column connected to the liquid outlet of the separation column;
a methane-removing column connected to the gas outlet of the separation column;
and the formaldehyde condensation tower is connected with a liquid outlet of the methane-removing tower.
9. The continuous synthesis system of claim 8, wherein the primary hydrolysis reaction device comprises a primary hydrolysis reaction tower and a primary hydrolysis reaction kettle;
the product solution outlet of the first-stage hydrolysis reaction tower is connected with the product solution inlet of the first-stage hydrolysis reaction kettle;
the gas outlet of the primary hydrolysis reaction kettle is connected with the gas inlet of the primary hydrolysis reaction tower;
the secondary hydrolysis reaction device comprises a secondary hydrolysis reaction kettle;
and a product solution inlet of the second-stage hydrolysis reaction kettle is connected with a product solution outlet of the first-stage hydrolysis reaction kettle.
10. The continuous synthesis system of claim 8, wherein the methanol column comprises a low pressure methanol column and a high pressure methanol column;
the liquid inlet of the low-pressure methanol tower is connected with the liquid outlet of the separation tower;
the liquid inlet of the high-pressure methanol tower is connected with the liquid outlet of the low-pressure methanol tower;
and a liquid outlet of the high-pressure methanol tower is connected with a second liquid phase inlet of the stripping tower.
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