CN1122809A - Process for prodn. of omethoate - Google Patents

Abstract

In condition of no basic change of raw materials and no major change of process equipment used in production of Omethoate with existing ammonolysis method, and by optimizing technological conditions, the three yields steps of sulfo-phosphorus amonium salt, oxy-sulfur phosphatides and Omethoate have been raised greatly, so that the total yield of Omethoate production is increased by above 20 percent and the original oil content is stabilized at above 80 percent. Advantages: low cost, stable product quality, simple technology and little wastes.

Description

Novel process for producing omethoate

The present invention belongs to the field of organophosphorus pesticide.

The invention relates to a new process for producing O, O-dimethyl-S- (methylamino formyl methyl) sulfur phosphate (I), and the compound is a pesticide with wide insecticidal spectrum, strong systemic property, high insecticidal activity and small resistance. The general name of the derivative is Omethoate (Omethonate) and the chemical structural formula is

In sixty to eighty years, a plurality of technical data (including patents) report the synthesis method of omethoate at home and abroad, and the main method comprises the following steps: preamine method (chloracetamide method), methyl isocyanate method, Bunte salt method, and post-amine method. The omethoate crude oil synthesized by adopting the pre-ammonolysis method and the Bunte method generates a large amount of inorganic salt waste residues in the production process, which causes great loss of omethoate in the extraction process, while the omethoate crude oil synthesized by adopting the methyl isocyanate method has the defects of difficult control of process conditions, great influence on the purity of omethoate, large toxicity of raw materials, high cost and serious corrosion to equipment, thus being difficult to popularize and apply in production because the omethoate crude oil is prepared by adopting the solid-liquid heterogeneous reaction.

The post-amination method has the advantages of easily obtained raw materials, simple process operation and convenient post-treatment, and is a currently and generally adopted omethoate production method in China. Phosphorus trichloride is taken as an initial raw material, and the method comprises the following four steps: general production process of dimethyl (mono) phosphite

The reaction formula is as follows:

the production process comprises the following steps:

and sequentially putting methanol and toluene into a reaction kettle, slowly dripping phosphorus trichloride for about 15 minutes under the conditions that the temperature is less than or equal to 30 ℃ and the vacuum degree is more than or equal to 67kPa, and rapidly deacidifying under the conditions that the temperature is controlled to be 60-70 ℃ and the vacuum degree is more than or equal to 67kPa after the dripping of the phosphorus trichloride is finished to obtain the toluene solution of dimethyl phosphite. General production process of ammonium (di) thiophosphoryl salt

The reaction formula is as follows:

the production process comprises the following steps:

and (3) sequentially putting the obtained toluene solution of dimethyl phosphite and sulfur powder into a reaction kettle, then slowly introducing liquid ammonia into the reaction kettle, controlling the ammonia introduction reaction temperature to be 25-35 ℃, keeping the temperature for reaction for 1 hour after ammonia introduction is finished, and adding water. Standing and layering to obtain the ammonium salt water solution of sulfur and phosphorus. General production process of (tri) oxysulfuryl phosphate

The reaction formula is as follows:

the production process comprises the following steps:

and (3) sequentially putting the obtained ammonium sulfate phosphate aqueous solution (with the pH value adjusted to 7-8) and methyl chloroacetate into a reaction kettle, reacting at the temperature of 58-64 ℃ for 2 hours, standing for layering after the reaction is finished, and performing reduced pressure desolventization on the crude ester to obtain the thiophosphate. General Process for producing omethoate (75 years reported in German patent Ger.110883)

The reaction formula is as follows:

the production process comprises the following steps:

and sequentially putting the obtained oxyphosphate and chloroform into a reaction kettle, precooling to-18 ℃, then slowly dripping methylamine (40%) at the temperature of less than or equal to-8 ℃, keeping the temperature for 40 minutes after finishing dripping, adding hydrochloric acid for neutralizing until the pH value is 6-7 after the reaction is finished, standing for layering, extracting the crude product for three times by using chloroform, and then carrying out decompression desolventizing, wherein the desolventizing end point temperature is 112 ℃, thus obtaining the omethoate crude oil.

Through the deep knowledge and a large amount of experiments of the prior post-amination production process, the following results are found: the reaction system of ammonium sulfate phosphate is a solid-liquid-gas heterogeneous system, and uneven and insufficient reaction is easily caused between materials. In the general process, the ammonia reaction temperature is too high and the ammonia concentration is too high locally, so that the by-products are increased, and the content and the yield of ammonium sulfate phosphate are influenced; the reaction system of the oxygen thiophosphate is a liquid-liquid heterogeneous system, materials are difficult to be fully mixed, the reaction temperature of the general process is too high, the reaction time is too long, so that the increase of by-products is caused, and the content and the yield of the oxygen thiophosphate are influenced; the omethoate aminolysis reaction system is also a liquid-liquid heterogeneous system, and the whole reaction process is relatively complex. The general process has too short reaction time, incomplete reaction, great loss of raw materials, too high reaction temperature, increased by-products and incomplete water removal during final desolventizing, which easily causes product decomposition and influences the purity and yield of omethoate.

The factors cause the low total yield (about 40 percent more) of the current domestic omethoate production and unstable crude oil content (less than 70 percent more).

The invention provides a scheme for optimizing various process conditions of the existing post-amination method production process on the basis of the existing post-amination method production process, and invents a new process capable of greatly improving the total yield of omethoate production and stabilizing the crude oil content.

The invention has the following changed processes for each step of synthesis: 1. in the existing synthesis reaction process of sulfur-phosphorus ammonium salt:

① the ammonia introduction and reaction temperature are reduced, and the ammonia introduction and reaction time is shortened;

② changing the ammonia introduction mode, 2, in the existing synthesis reaction process of the oxygen sulfur phosphorus ester:

① shortening the reaction time and reducing the reaction temperature;

② adding catalyst into the reaction system;

③, changing the desolventizing condition and the desolventizing mode of the crude product, 3, in the existing omethoate aminolysis reaction process:

① use a homogeneous reaction system without solvent or a quasi-homogeneous reaction system with small amount of solvent

Is a step of;

② changing the reaction temperature and prolonging the reaction time;

③ changing the concentration of the raw material methylamine;

④ the desolventizing condition and the desolventizing mode of the crude product are changed.

The conditions for optimizing the process in each step are as follows: firstly, producing sulfur-phosphorus ammonium salt: 1. the ammonia introduction and reaction temperature is controlled to be 5-25 ℃, and the ammonia introduction and reaction time is controlled to be 3-6 hours; 2. the ammonia introducing pipe is changed into a multi-hole pipe or a multi-hole coil pipe. Secondly, producing the oxygen sulfur phosphorus ester: 1. the reaction temperature is controlled to be 50-60 ℃, and the reaction time is controlled to be 60-150 min

A clock is suitable; 2. adding a phase transfer catalyst into a reaction system, controlling the reaction temperature to be 40-60 ℃,

the reaction time is suitably controlled to be 40-80 minutes; 3. the catalyst can be selected from aliphatic and aromatic quaternary ammonium salts with total carbon number of 10-28

Phosphorus salts, and combinations thereof, e.g. benzyltrimethylammonium halide, tetrabutylphosphonium halide

Ammonium, dodecyl triethyl ammonium halide, trioctyl methyl ammonium halide, etc. transfer catalyst

And their complex (the halide ion can be chlorine, bromine, iodine anion, etc.); 4. the dosage of the catalyst is 1-5% of the pure amount of the ammonium salt; 5. adding a proper amount of water-containing solvent of toluene or sec-butyl alcohol into the crude product of the thiophosphate, and carrying out decompression desolventizing; 6. when the crude product of the oxygen sulfur phosphorus ester is purified, a distillation kettle with a throwing disc connected with a stirrer is adopted for reducing

Pressure exsolution. Thirdly, producing omethoate crude oil: 1. adopts a solvent-free homogeneous reaction system, and about one fifth of chloroform or water in the original process can also be added

A quasi-homogeneous reaction system as a solvent; 2. the concentration of the raw material methylamine is appropriate to be 20-40%; 3. the reaction temperature is controlled to be-10 to-20 ℃, and the reaction time is controlled to be 40 to 90 DEG

Minutes are suitable; 4. adding appropriate amount of benzene or toluene solvent with water into the crude product, and desolventizing under reduced pressure

The end point temperature is suitably 70 to 100 ℃; 5. the crude product is purified by a distillation still with a throwing disc connected with a stirrer for decompression and dehydration

And (4) dissolving.

The invention carries out all-round optimization on various process conditions for producing the omethoate by the aminehydrolysis method after the old process, and under the condition of basically not changing production raw materials and not greatly moving process equipment, the total yield of the omethoate production is improved by more than 20 percent, and the crude oil content is stabilized at about 80 percent. It has the advantages of less investment, quick effect, high benefit, less three wastes, etc.

To help better understand the present invention, experimental results under several process conditions, and examples and comparative examples of pilot and industrial tests are given below.

Table one: industrial test results for the Synthesis of ammonium Phosphothios

The test result shows that: the ammonium salt content of the ammonium salt synthesized by the new process is improved by 1.5 percent compared with the ammonium salt synthesized by the old process, and the yield is equivalent to be improved by 5.4 percent (compared with the batch numbers 32 and 34).

Table two: small test results for catalytic synthesis of oxathiophosphate

The experimental results show that: by adopting the new process (adding a certain amount of catalyst), the reaction time can be shortened (experiments 1, 2 and 3), the reaction temperature is reduced (experiment 3), the generation of by-products is reduced, the content of the oxygen magnetic phosphate is greatly improved, and the average yield of the oxygen sulfur phosphate is improved by about 15 percent compared with the old process. Up to 21.4% (experiment 1 vs experiment 4).

Table three: test result for optimizing omethoate crude oil small test process condition

Experiment 1 shows that: the crude oil content is not obviously changed even if the concentration of the raw material methylamine is changed by adopting the old process reaction conditions.

Experiments 2, 3, 4, 5 show that: by adopting the new process reaction conditions and changing the concentration of the raw material methylamine, the average content of the crude oil can be improved by about 5 percent (compared with the experiment 6).

Experiments 2 and 5 show that: the reaction system, reaction conditions and post-treatment method of the old process are optimized in an all-round way, so that the content and yield of the crude oil are greatly improved. The average crude oil content is improved by 1.5 percent compared with experiments 3 and 4, improved by 7.2 percent compared with the prior art (experiment 1), and the average crude oil yield is improved by 4 percent compared with experiments 3 and 4 and improved by 9.45 percent compared with experiment 1.

Table four: industrial test results for omethoate solventless aminolysis reaction

The test result shows that: compared with the crude oil content of the old process, the new process can averagely improve the crude oil content by more than 5 percent.

The old technology (reaction time 120 minutes) and the new technology (reaction time 80 minutes) of the thiophosphate are respectively compared with the actual production of 35 batches, and the thiophosphate obtained by the new technology and the old technology is respectively used for the actual production of 70 batches of crude oil according to the crude oil synthesis method of the old technology. The statistical results show that: compared with the prior art (the reaction time is 120 minutes), the average content of the oxysulfide phosphate obtained by adopting the new process (the reaction time is 80 minutes) is increased by 1.9 percent, the average content of the crude oil is increased by 3.4 percent, the quality of the product is stable, and the content of the crude oil is basically stabilized to be more than 70 percent.

[ example 1]

Putting 1mol of 24.8% dimethyl phosphite toluene solution into a reaction bottle, then adding equimolar sulfur powder, precooling to 10 ℃ under stirring, starting to slowly introduce 1.4mol of ammonia gas, keeping the ammonia introduction temperature at about 15 ℃, introducing ammonia and reacting for 3 hours, then adding 175g of water, standing for layering, removing the upper layer of toluene, and measuring the content of the lower layer of ammonium salt aqueous solution to be 42.4%.

[ COMPARATIVE EXAMPLE 1]

The raw materials, the feeding amount and the experimental steps are the same as those of the example 1, but the ammonia introducing temperature is kept at about 30 ℃, the heat preservation time is 1 hour after the ammonia introducing is finished, and the content of the ammonium salt aqueous solution is finally obtained and is 40.3 percent.

[ Industrial example 1]

Putting 1350Kg of 23.8 percent dimethyl phosphite toluene solution into a reaction kettle, then adding 120Kg of sulfur powder, slowly introducing 100Kg of liquid ammonia under stirring, keeping the ammonia introduction temperature at about 15 ℃, introducing ammonia for reaction for 6 hours, adding 650Kg of water, standing and layering to obtain 1600Kg of ammonium salt aqueous solution with the content of 41.5 percent.

[ Industrial comparative example 1]

The raw materials, the feeding amount and the experimental steps are the same as those of the industrial example 1, but the ammonia introducing temperature is kept at about 30 ℃, the heat preservation time is 1 hour after the ammonia introducing is finished, and 1550Kg of ammonium salt aqueous solution with the content of 40.4 percent is obtained.

[ example 2]

Placing 0.5mol of 40.1% ammonium salt aqueous solution into a reaction bottle, then adding 2.25mol of methyl chloroacetate, stirring, controlling the temperature to be 55-60 ℃, reacting for 60 minutes, standing for layering after the reaction is finished, removing a water layer, carrying out reduced pressure distillation on the obtained crude ester, and recovering excessive methyl chloroacetate, wherein the amount of refined ester (namely the phosphorothioate) is 100.0g, the chromatographic content is 84.2%, and the yield is 78.7%.

[ example 3]

The raw materials, the feeding amount and the experimental steps are the same as those of the example 2, but the reaction time is 80 minutes, the final obtained refined ester amount is 98.0g, the chromatographic content is 89.6 percent, and the yield is 81.7 percent.

[ example 4]

386.0g of 41.0% ammonium salt aqueous solution and 488.0g of methyl chloroacetate are respectively placed in a reaction bottle, 6.4g of tetrabutylammonium iodide is added, the temperature is controlled to be about 55 ℃ under stirring, the reaction is carried out for 60 minutes, the following steps are carried out in the same way as the example 2, and finally the amount of the obtained refined ester is 200.7g, the chromatographic content is 94.4%, and the yield is 90.2%.

[ example 5]

The raw materials, the feeding amount and the experimental steps are the same as those of example 4, but the catalyst is changed into benzyl tributyl ammonium chloride, the final refined ester amount is 200.8g, the chromatographic content is 90.9%, and the yield is 85.3%.

[ comparative example 2]

The raw materials, the feeding amount and the experimental steps are the same as those of example 4, but the reaction temperature is controlled to be 58-62 ℃, the reaction time is 2 hours, the final obtained refined ester amount is 193.0g, the chromatographic content is 83.0 percent, and the yield is 76.3 percent.

[ Industrial example 2]

1300Kg of 40.4 percent ammonium salt water solution and 1600Kg of methyl aminoacetate are sequentially put into a reaction kettle, stirred, the temperature is controlled to be 58-60 ℃, the reaction is carried out for 80 minutes, standing and layering are carried out, the obtained crude ester is subjected to reduced pressure distillation, the yield of the thiophosphate is 700Kg, the chromatographic content is 83.2 percent, and the yield is 82.7 percent.

[ Industrial control example 2]

The raw materials, the feeding amount and the experimental steps are the same as those of the industrial example 2, but the reaction temperature is controlled to be 58-62 ℃, the reaction time is 2 hours, 680Kg of phosphorothioate is obtained, the chromatographic content is 79.4 percent, and the yield is 76.3 percent.

[ example 6]

Putting 270.0g of 79% oxathiophosphate in a reaction bottle, stirring, precooling to-15 ℃, starting to dropwise add 165.0g of methylamine (40%), controlling the temperature to be below-11 ℃, keeping the temperature for reaction for 60 minutes after dropwise addition, neutralizing with hydrochloric acid until the pH value is 6-7, extracting with chloroform, adding 50g of toluene into the crude product, and performing decompression desolventizing at the final desolventizing temperature of 95 ℃. The amount of omethoate crude oil obtained was 251.1g, the content by thin layer analysis was 70.0%, and the yield was 82.5%.

[ example 7]

The raw materials, the feeding amount and the experimental steps are the same as those of example 6, but the concentration of methylamine is 30%, the obtained omethoate crude oil amount is 266.6g, the content is 73.5%, and the yield is 92.0%.

[ control example 3]

The raw materials, the material loading and the experimental steps are the same as those in example 6, however, 338g of chloroform solvent is added into the reaction system, the concentration of methylamine is 30%, the reaction temperature is below-8 ℃, the heat preservation time is 40 minutes, the crude product is directly desolventized without adding toluene to obtain 248.1g of omethoate crude oil, the content of thin layer analysis is 65.8%, and the yield is 82.3%.

[ Industrial example 3]

Putting 400Kg of thiophosphate (79.2%) into a reaction kettle, precooling to-15 ℃ under stirring, beginning to dropwise add 180Kg of 40% methylamine, controlling the temperature below-10 ℃, keeping the temperature for reaction for 60 minutes after the dropwise addition is finished, then neutralizing with hydrochloric acid until the pH value is 6-7, extracting with chloroform, adding 50Kg of toluene into the crude product, and carrying out decompression desolventizing at the final desolventizing temperature of 95 ℃. The crude oil of the omethoate is 360Kg, the content of the TLC is 72.7 percent, and the yield is 82.6 percent.

[ Industrial example 4]

Putting 420Kg of thiophosphate (79.8%) into a reaction kettle, stirring, precooling to-15 ℃, adding 60Kg of water, beginning to dropwise add 190Kg of 40% methylamine, controlling the temperature below-11 ℃, keeping the temperature for 60 minutes after dropwise addition, then neutralizing with hydrochloric acid until the pH value is 6-7, extracting with chloroform, decompressing and desolventizing, wherein the desolventizing end point temperature is 112 ℃. The crude oil of the omethoate is 380Kg, the content of the TLC is 77.6 percent, and the yield is 88.3 percent.

[ Industrial example 5]

Putting 420Kg of thiophosphate (79.2%) into a reaction kettle, stirring, precooling to-15 ℃, adding 100Kg of chloroform, beginning to dropwise add 180Kg of 40% methylamine, controlling the temperature below-10 ℃, keeping the temperature at the end of dropwise addition for 60 minutes, then neutralizing with hydrochloric acid until the pH value is 6-7, extracting with chloroform, and carrying out decompression and desolventization at the end temperature of desolventization of 110 ℃. The crude oil amount of the omethoate is 355Kg, the content of the TLC is 72.3 percent, and the yield is 81.4 percent.

[ Industrial example 6]

Putting 420Kg of thiophosphate (81.0%) into a reaction kettle, precooling to-15 ℃ under stirring, beginning to dropwise add 189Kg of 30% methylamine, controlling the temperature below-10 ℃, keeping the temperature for reaction for 60 minutes after dropwise addition, then neutralizing with hydrochloric acid until the pH value is 6-7, extracting with chloroform, and carrying out decompression and exsolution. The crude oil amount of the omethoate is 390Kg, the content of the thin layer analysis is 79.3 percent, and the yield is 91.3 percent.

[ Industrial control example 3]

The raw materials, the feeding amount and the experimental steps are the same as those of the industrial example 3, however, 500Kg of chloroform solvent is added before the reaction, the heat preservation time is 40 minutes, the crude product is directly desolventized without adding toluene to obtain 350Kg of omethoate crude oil, the content of the thin layer analysis is 67.8 percent, and the yield is 75.3 percent.

Partial industrial test results (table one) for synthesis of ammonium sulfate phosphate reaction materials and amounts: 450Kg of dimethyl phosphite, 120Kg of sulfur powder and 100Kg of ammonia gas as solvent: toluene 900Kg

Test of Batch number	Phosphorous acid dimethyl ester		Introducing ammonia and reaction temperature (℃)	Chemical analysis of plant	Phosphorus Spectrum analysis (%)		Remarks for note
								Feed amount	Content (wt.)	Ammonium salt content	Ammonium salts	Impurities and by-products
	23	1350		23.8	14～16	41.51							87.0	13.0	New process
32			1350				23.1	18～22	41.98	88.0	12.0	New process
	34	1350		28～32	40.44	85.0							15.0	Old process

Partial small-test results (table two) of catalytic synthesis of oxathiophosphate reaction materials and amounts: 386.0g of ammonium salt and 488.0g of methyl chloroacetate

Serial number	Catalyst and process for preparing same	Amount of catalyst (g)	Temperature of heat preservation (℃)	Time of heat preservation (min)	Amount of crude ester (g)	Amount of essential ester (g)	Chromatographic content (％)	Phosphorus spectrum content (%)		Yield of (％)	Ammonium salt concentration (Subdivision) (％)
												Thiophosphoryl ester	By-products
								1	YFR-1					4.8	58～60	60	538.7	224.7	92.99	92.0	8.0	97.7	41.17
2	YFR-2	6.4	"	"	540.6	200.8	90.87			92.4	7.6	85.3	"
								3	YFR-3					6.4	55	"	554.2	200.7	94.39	94.7	5.3	90.2	"
4	/	/	58～62	120	550.4	193.0	83.04			91.2	8.8	76.3	"

Note: YFR-1 is trinonyl methyl ammonium iodide, YFR-2 is benzyl tributyl chloride, YFR-3 is tetrabutyl ammonium iodide

Partial test results (table three) of the omethoate crude oil pilot plant process condition optimization reaction materials and amounts: thiophosphate 270.0g, methylamine 1.25mol solvent: chloroform

Serial number	Variation and optimization of the respective process conditions					After desolventizing Crude oil quantity (g)	Phosphorus spectrum content (%)			Sheet metal Chromatography Content (wt.)	Harvesting machine Rate of change (％)	Thiophosphoryl ester Chromatographic content (％)
													Reaction system	Concentration of methylamine	Reaction temperature	Reaction time	Adding benzene for desolventizing	Crude oil	Thiophosphoric acid esters	By-products
	1	340g chloroform	30％	＜-8℃	40min			248.1	79.0												7.0	14.0	65.8	82.3	73.80
2						Solvent-free				"	＜-11℃	60min	80g of benzene	266.6	91.0	0.9	8.1	73.5	92.0	79.27
	3	"	"	"	"			257.0	95.0												0.5	4.5	72.7	87.7	"
4						"				"	"	"		246.3	85.3	0.9	13.8	70.7	87.8	73.80
	5	"	"	"	"		80g of benzene	250.3	83.0												0.5	16.5	72.5	91.5	"
6						"				40％	＜-10℃	"	80g of benzene	251.1	88.0	0.7	11.3	70.0	82.5	79.27

Omethoate solventless aminolysis reaction partial industrial test results (table tetra) oxathiophosphates: 400Kg, methylamine: 180Kg, solvent: chloroform 27 days 6 to 12 days 7 in 1994

Sequence of steps Number (C)	Date of experiment	Batch number of factory	Thiophosphoryl ester (％)	Selection of the Process	Results of plant analysis			Results of phosphorus spectrum analysis			Reference batch number	Content phase difference%
													Crude oil content	Acidity of the solution	Water content	Sulfur driving	Triesters and the like	Refined esters
					1	6.28 white	449	96.06	New process	70.57									0.16	0.88	78.0	13.0	5.0	452	+7.37
2	6.28 white	451	96.06	New process							68.20	0.15	0.86	/	/	/	452	+5.0
					3	6.28 white	452	96.06	Old process	63.20									0.12	0.50	73.5	13.0	12	449，451
4	6.29 white	1	93.18	New process							66.19	0.12	0.42	/	/	/	2	+4.76
					5	6.29 white	4	93.18	New process	66.09									0.18	1.25	/	/	/	2	+4.66
6	6.29 white	2	93.18	Old process							61.63	0.12	0.46	/	/	/	1，4

Claims (7)

1. An improved process for synthesizing omethoate crude oil from thiophosphate and methylamine

As a raw material, omethoate crude oil is synthesized. The method is characterized in that: controlling the reaction temperature to-10

The reaction time is 40 to 90 minutes at the temperature of minus 20 ℃.

2. A method according to claim 1, characterized in that: a solvent-free homogeneous reaction system is used.

3. A method according to claim 1, characterized in that: one fifth of the original process is adopted

A quasi-homogeneous reaction system with chloroform or water as solvent.

4. The process according to claim 2, wherein the concentration of the starting methylamine is 20 to 40%.

5. A method according to claim 1, characterized in that: adding proper amount of benzene or toluene into the crude product

Benzene was desolventized with water under reduced pressure.

6. A process according to claim 5, wherein the end point temperature of the desolvation is 90 to 100 ℃.

7. A method according to claim 1, characterized in that: the crude product is purified by adopting a centrifugal pump

And a distillation kettle connected with the disc and the stirrer is used for decompression and desolventizing.