A method for purifying high-quality methylpyrimidine phosphorus

Abstract

This invention discloses a purification method for high-quality methylpyrimidine phosphorus, comprising the following steps: mixing crude methylpyrimidine phosphorus with a lower alcohol and dilute hydrochloric acid solution, and stirring at 20℃~40℃ for 0.5h~2h; cooling the solution to -10℃~0℃ to crystallize, filtering, mixing the filter cake with methyl isobutyl ketone, and then heating to 45℃~65℃ to desolvate under reduced pressure to obtain high-quality methylpyrimidine phosphorus. The high-quality methylpyrimidine phosphorus obtained by this purification method has a main content ≥99.13%, isomethylpyrimidine phosphorus controlled below 0.3%, other impurities controlled below 0.1%, and a yield ≥96.5%. The method is simple to operate and easy for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical intermediate preparation technology, and particularly relates to a purification method for high-quality methylpyrimidine phosphorus. Background Technology

[0002] Pirimiphos-methyl (also known as Andeli, PP511, English common name Pirimiphos-methyl) is a pyrimidine insecticide developed by ICI in the UK in 1970. It acts rapidly, has strong penetrating power, and combines contact, stomach poison, and fumigation effects, with long-lasting efficacy on inert surfaces. Pirimiphos-methyl is not only used to control chewing and sucking pests and larvae on fruit trees, cotton, and vegetables, but it is also highly effective against grain storage pests and sanitary pests, making it an excellent choice for controlling these pests. Compared to general insecticides, pyrimimiphos-methyl has advantages such as lower dosage and longer residual effect. With the complete ban on the production, sale, and use of key organophosphate insecticides in China, such as phosmet, phosmet, methyl parathion, ethyl parathion, and methamidophos, pyrimimiphos-methyl is bound to become a suitable substitute, possessing excellent market prospects and development potential.

[0003] Methylpyrimidine phosphate is a low-toxicity insecticide that can be widely used. However, in 2007, the Food and Agriculture Organization of the United Nations (FAO) imposed strict requirements (below 0.5%) on the content of carcinogenic and teratogenic harmful impurities in methylpyrimidine phosphate technical grade (O,O'-dimethylthiophosphoric acid chloride, O,O,S-trimethyldithiophosphate, O,O,S-trimethylthiophosphate, O,O,O-trimethylthiophosphate, and isomethylpyrimidine phosphate). Other unlisted highly toxic impurities to humans and animals must each be less than 0.1%. Even if the main content of methylpyrimidine phosphate technical grade is greater than 98%, if any of the above harmful impurities exceeds the limit, it cannot obtain pesticide registration and sale in developed countries in Europe and America. Due to the overly stringent impurity limits, it is difficult for products produced by Chinese agrochemical companies to meet the procurement requirements of European and American countries.

[0004] The commonly used synthesis method for methylpyrimidine phosphorus involves reacting 2-diethylamino-6-methyl-4-hydroxypyrimidine (pyrimidinol) with O,O'-dimethylthiophosphoric chloride (methyl chloride) in the presence of an acid-binding agent. Because methyl chloride has a foul odor, an excess of pyrimidinol is required to ensure complete reaction of the methyl chloride in order to produce odorless methylpyrimidine phosphorus. Furthermore, methyl chloride has poor stability, and various small impurities are generated during storage and reaction. The resulting methylpyrimidine phosphorus reaction solution contains multiple impurities. Washing with approximately 4.5 tons of water per ton of product can reduce some impurities. However, to meet the procurement requirements of European and American countries, special purification methods are needed, which consumes a great deal of energy and generates large amounts of phosphorus-containing wastewater that is difficult to treat. Therefore, it is necessary to develop a new purification method for high-quality methylpyrimidine phosphorus to reduce impurity removal costs, decrease the generation of waste gas, wastewater, and solid waste, and increase enterprise profits. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a purification method for high-quality methylpyrimidine phosphate with high content and yield, few impurities, simple process and easy industrialization.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] A method for purifying high-quality methylpyrimidine phosphate includes the following steps:

[0008] (1) Mix crude methylpyrimidine phosphate, lower alcohol and dilute hydrochloric acid, and keep warm at 20℃~40℃ and stir for 0.5h~2h;

[0009] (2) Cool the solution obtained in step (1) to -10℃~0℃ to crystallize and filter;

[0010] (3) The filter cake obtained in step (2) is mixed with methyl isobutyl ketone and heated to 45℃~65℃ for desolvation under reduced pressure to obtain high-quality methylpyrimidine phosphorus, wherein the main content of methylpyrimidine phosphorus in the high-quality methylpyrimidine phosphorus is ≥99.13% and the yield is ≥96.5%.

[0011] In the above-mentioned method for purifying high-quality methylpyrimidine phosphorus, preferably, the lower alcohol is one of methanol, ethanol, propanol, and isopropanol.

[0012] In the above-mentioned method for refining high-quality methylpyrimidine phosphorus, preferably, the mass ratio of crude methylpyrimidine phosphorus to lower alcohol is 1:0.5-2.

[0013] In the above-mentioned purification method for high-quality methylpyrimidine phosphorus, preferably, the mass fraction of the dilute hydrochloric acid is 0.5% to 2.5%.

[0014] In the above-mentioned method for refining high-quality methylpyrimidine phosphorus, preferably, the mass ratio of crude methylpyrimidine phosphorus to dilute hydrochloric acid is 1:0.2 to 0.8.

[0015] In the above-mentioned method for refining high-quality methylpyrimidine phosphate, preferably, the mass ratio of crude methylpyrimidine phosphate to methyl isobutyl ketone is 1:0.2-1.

[0016] In the above-mentioned purification method for high-quality methylpyrimidine phosphorus, preferably, the high-quality methylpyrimidine phosphorus contains 99.13% to 99.68% methylpyrimidine phosphorus by mass fraction, has a yield of 96.5% to 98.3%, isomethylpyrimidine phosphorus is controlled below 0.3%, and other impurities are controlled below 0.1%.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] 1. The method of the present invention leaves impurities in the mother liquor, so that crude methylpyrimidine phosphate is purified in one operation to obtain high-quality methylpyrimidine phosphate with a main content ≥99.13% (99.13%~99.68%), isomethylpyrimidine phosphate controlled below 0.3%, and other impurities controlled below 0.1%, meeting the procurement requirements of European and American countries, and the yield ≥96.5% (96.5%~98.3%).

[0019] 2. The method of the present invention reduces wastewater generation, lowers energy consumption, and reduces the cost of removing impurities from methylpyrimidine phosphorus.

[0020] 3. The method of the present invention is simple in process, easy to operate, and easy to industrialize. Detailed Implementation

[0021] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available, and all contents refer to mass fractions.

[0022] In the following examples, the crude methylpyrimidine phosphorus was obtained by desolvation of the methylpyrimidine phosphorus reaction solution without water washing, wherein the content of methylpyrimidine phosphorus was 96.02%, the content of isomethylpyrimidine phosphorus was 0.68%, the content of methyl chloride was 0.08%, the content of pyrimidine alcohol was 1.68%, and the content of ether was 1.04%.

[0023] Example 1:

[0024] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0025] (1) Mix 100g of crude methylpyrimidine phosphate with 50g of methanol and 80g of 0.5% dilute hydrochloric acid solution, and keep warm and stir at 20℃ for 0.5h;

[0026] (2) Cool the solution to -10℃ to crystallize and filter;

[0027] (3) The filter cake was mixed with 20g of methyl isobutyl ketone and heated to 45℃ to desolvate under reduced pressure, yielding 93.8g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.35%, an isomethylpyrimidine phosphorus content of 0.21%, and other impurities controlled below 0.1%, with a yield of 97.1%.

[0028] Example 2:

[0029] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0030] (1) Mix 100g of crude methylpyrimidine phosphate with 80g of ethanol and 70g of 0.7% dilute hydrochloric acid solution, and keep warm and stir at 25℃ for 1h;

[0031] (2) Cool the solution to 0℃ to allow crystallization and filter;

[0032] (3) After mixing the filter cake with 40g of methyl isobutyl ketone, the mixture was heated to 50℃ and desolventized under reduced pressure to obtain 94.2g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.61%, an isomethylpyrimidine phosphorus content of 0.24%, and other impurities controlled below 0.1%, with a yield of 97.7%.

[0033] Example 3

[0034] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0035] (1) Mix 100g of crude methylpyrimidine phosphate with 120g of propanol and 60g of 1% dilute hydrochloric acid solution, and keep warm at 30℃ and stir for 1.5h;

[0036] (2) Cool the solution to -10℃ to crystallize and filter;

[0037] (3) The filter cake was mixed with 60g of methyl isobutyl ketone and heated to 55℃ to desolvate under reduced pressure, yielding 95.2g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.13%, an isomethylpyrimidine phosphorus content of 0.27%, and other impurities controlled below 0.1%, with a yield of 98.3%.

[0038] Example 4

[0039] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0040] (1) Mix 100g of crude methylpyrimidine phosphate with 150g of methanol and 50g of 1.3% dilute hydrochloric acid solution, and keep warm at 35℃ for 2h with stirring.

[0041] (2) Cool the solution to -5℃ to crystallize and filter;

[0042] (3) The filter cake was mixed with 80g of methyl isobutyl ketone and heated to 60℃ to desolvate under reduced pressure, yielding 94.8g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.37%, an isomethylpyrimidine phosphorus content of 0.25%, and other impurities controlled below 0.1%, with a yield of 98.1%.

[0043] Example 5

[0044] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0045] (1) Mix 100g of crude methylpyrimidine phosphate with 180g of ethanol and 40g of 1.8% dilute hydrochloric acid solution, and keep warm at 40℃ and stir for 0.5h;

[0046] (2) Cool the solution to -10℃ to crystallize and filter;

[0047] (3) After mixing the filter cake with 100g of methyl isobutyl ketone, the mixture was heated to 65℃ and desolventized under reduced pressure to obtain 94.4g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.51%, an isomethylpyrimidine phosphorus content of 0.23%, and other impurities controlled below 0.1%, with a yield of 97.8%.

[0048] Example 6

[0049] A method for purifying high-quality methylpyrimidine phosphate according to the present invention includes the following steps:

[0050] (1) Mix 100g of crude methylpyrimidine phosphate with 200g of isopropanol and 20g of dilute hydrochloric acid solution with a content of 2.5%, and keep warm at 35℃ and stir for 1h;

[0051] (2) Cool the solution to -5℃ to crystallize and filter;

[0052] (3) The filter cake was mixed with 80g of methyl isobutyl ketone and heated to 50℃ to desolvent under reduced pressure to obtain 93g of colorless oily substance, which is high-quality methylpyrimidine phosphorus, with a methylpyrimidine phosphorus content of 99.68%, an isomethylpyrimidine phosphorus content of 0.19%, and other impurities controlled below 0.1%, with a yield of 96.5%.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for purifying high-quality methylpyrimidine phosphate, comprising the following steps: (1) Mix crude methylpyrimidine phosphate, lower alcohol and dilute hydrochloric acid, and keep warm at 20℃~40℃ and stir for 0.5 h~2 h; (2) Cool the solution obtained in step (1) to -10℃~0℃ to crystallize and filter; (3) The filter cake obtained in step (2) is mixed with methyl isobutyl ketone and heated to 45℃~65℃ for desolvation under reduced pressure to obtain high-quality methylpyrimidine phosphorus, wherein the main content of methylpyrimidine phosphorus in the high-quality methylpyrimidine phosphorus is ≥99.13% and the yield is ≥96.5%; The lower alcohol is one of methanol, ethanol, propanol, and isopropanol; The mass ratio of crude methylpyrimidine phosphate to lower alcohol is 1:0.5-2; The mass fraction of the dilute hydrochloric acid is 0.5% to 2.5%; The mass ratio of crude methylpyrimidine phosphate to dilute hydrochloric acid is 1:0.2 to 0.

8.

2. The method for purifying high-quality methylpyrimidine phosphorus according to claim 1, characterized in that, The mass ratio of crude methylpyrimidine phosphate to methyl isobutyl ketone is 1:0.2-1.

3. The method for purifying high-quality methylpyrimidine phosphorus according to claim 1 or 2, characterized in that, In the high-quality methylpyrimidine phosphorus, the main content of methylpyrimidine phosphorus is 99.13% to 99.68% by mass fraction, the yield is 96.5% to 98.3%, isomethylpyrimidine phosphorus is controlled below 0.3%, and other impurities are controlled below 0.1%.