CN1278531A

CN1278531A - Preparation of refined organic thiosulfate

Info

Publication number: CN1278531A
Application number: CN 99108807
Authority: CN
Inventors: 段成钢; 唐庄
Original assignee: Guizhou Qunxing Scientific Technical & Economic Cooperation Co
Current assignee: Guizhou Qunxing Scientific Technical & Economic Cooperation Co
Priority date: 1999-06-18
Filing date: 1999-06-18
Publication date: 2001-01-03

Abstract

The present invention adopts 1-dimethylamino-2,3-dichoropropane hydrochloride refined product as raw material and utilizes the thoisulfonation reaction to directly prepare high-concentration sulfonated raw liquor, and makes said raw liquor undergo the processes of crystallization control and high-effective centrifugal separation to obtain the invented refined product whose structural formula is (CH3)2NH+CH(CH2SSO3-)2.Y2(Na)2.HzO. It is a high-effective low-toxic broad-spectrum pesticide, and the present invention is high in content, and high in yield of said product.

Description

Preparation method of refined organic thiosulfate

The invention relates to a method for producing raw organic thiosulphate powder for use as an active ingredient in chemical pesticides. In particular, it relates to a process for the preparation of the monohydrate-dimethyl-hydrido-2- (1, 3-dithiosulfonic acid monosodium propyl) ammonium salt [1].

(CH₃)₂NH⁺CH(CH₂SSO₃ ^-)₂·1／2(Na⁺)₂·H₂O………………[1]

As methods for producing the compound [1], there are mainly the following two methods.

The first method is that sodium thiosulfate pentahydrate is heated to be in a molten state, and then solvent (alcohol or water) and 1-dimethylamino-2, 3-dichloropropane [ A]are added](or hydrochloride thereof [ A. HCl]]Adding alkali with equal mole), sulfonating at pH 8-9 at 60-70 deg.C under vigorous stirring, acidifying with hydrochloric acid, and directly cooling and crystallizing to obtain [1]]. The reaction formula is as follows:

[A][B][C]

[B][D]

[D][1]

this method is described in detail in the document CN 1012898B.

The first method, in which the sulfonation is carried out under alkaline conditions at pH 8-9, although favouring the isomerization, has the following disadvantages: 1. under alkaline conditions, the stability of the product [ B]is not favorable, and the alkaline hydrolysis of the [ B]is accelerated. 2. The method is characterized in that a raw material compound [ A]is prepared or the raw material compound [ A.HCl]is added with alkali with the same mole for neutralization, so that the process is complex, in the process of preparing the compound [ A]or adding the [ A.HCl]into the alkali for neutralization, the side reaction of alkaline hydrolysis is great, the consumption of raw materials is increased, 3, the sulfonation reaction is heterogeneous, the stirring is intensified, and the sulfonation yield is only about 90%. 4. During crystallization, seed crystals are not added, the cooling rate is not controlled, the crystals are very fine, impurities are substituted, and the quality of the crystal is influenced by the method [1].

The second method comprises the following steps: adding methanol as solvent into [ A.HCl]]Adding alkali to partially neutralize the solution to pH 4-7, and reacting with Na under acidic condition₂S₂O₃Heating for sulfonation reaction, acidifying with hydrochloric acid, or directly cooling for crystallization, or heating for evaporation to recover methanol and cooling for crystallization to obtain [1]. The method is loaded in detail in the document CN 1086210A.

In the second method, although the step of preparing [ A]is omitted, the following disadvantages remain: the sulfonation reaction of 1 is carried out under the acidic condition of PH 4-7, which is not beneficial to sulfonation isomerization transposition and stability of the product [ D], accelerates the acidic degradation of the [ D]and influences the yield of the effective body. 2. After the sulfonation reaction is finished, the product is acidified to PH 2-5 by hydrochloric acid, and the methanol solvent is recovered by heating and distilling under an acidic condition, so that the acidic degradation of the product [ D]is increased, and the sulfonation yield is further influenced. 3. The problems in crystallization are the same as in the first method.

The invention aims to provide a preparation method of an organic thiosulfate competitive product, which is beneficial to sulfonation isomerization and transposition, can increase the stability of a sulfonated product, improves the sulfonation yield and can improve the quality of a product [1].

In order to achieve the above object, the method of the present invention is characterized in that: the method comprises the steps of using a [ A&HCl]refined solution or a solution prepared from a solid of the [ A&HCl]refined solution as a raw material, adding an alkali or alkaline substance at a low temperature to adjust the solution to be neutral, adding sodium thiosulfate pentahydrate under the neutral condition, heating the solution to perform sulfonation reaction, and directly preparing a high-concentration sulfonation stock solution. Then the sulfonation stock solution is stirred at low speed under the condition of controlled temperature reduction. Adding crystal seeds at proper time, regulating the crystal seeds to the vicinity of isoelectric point (about pH 5.1) by using hydrochloric acid or hydrogen chloride gas or dilute sulfuric acid and the like to ensure that crystals grow normally and crystal products [1]are separated out, separating the crystals by using a centrifuge with higher separation factor after the crystallization is finished, washing the crystals by using a solvent for several times, and drying the crystals by a conventional method to prepare high-quality organic thiosulfate raw powder [1]products.

The method of the invention comprises the following steps: 1-dimethylamino-2, 3-dichloropropane hydrochloride [ A.HCl]fine solution or solution prepared by using alcohol or water or alcohol-water mixed solvent as solid is added with alkali or alkaline substance to adjust the pH to 7 at the low temperature of 5-15 ℃, then sodium thiosulfate pentahydrate is added into the feed liquid, and the mixture is heated to 60-85 ℃ under the neutral condition to carry out heat preservation reaction for 3-4 hours. After the sulfonation is finished, a by-product NaCI is separated out by filtering and settling while the sulfonation is hot, and a high-concentration sulfonation stock solution is directly prepared. The method comprises the following steps of (1) crystallizing the high-concentration sulfonation stock solution by adopting a cooling method: stirring at 10-40 rpm, cooling at 60-10 deg.C, cooling at 0.5-8 deg.C per hour, and adding enough seed crystal at 60-20 deg.C; adjusting the pH of the feed solution toisoelectric point (about pH 5.1) with hydrochloric acid (or HCl gas or dilute sulfuric acid); so that the crystal grows normally to meet the quality requirement of the product [1]. The inventor notices that if the temperature is reduced too fast, or the seed crystal is not properly added, or the pH value of the feed liquid is far away from the isoelectric point, the crystallization effect is not good, the crystal is too fine, the carried impurities are more, the product quality is poor, and the powder yield is reduced.

After crystallization, a centrifuge with high separation factor is selected to separate crystal and mother liquor, the separation factor is required to be more than 1000, after the mother liquor is separated, a solvent is sprayed in times to fully wash filter cakes, and the solvent used for washing can be alcohol, water or alcohol-water mixed solution and the like, and methanol or methanol-water solution is preferably used. The separated wet crystallized powder is prepared into the product [1]by a conventional method such as a flash evaporation dryer and the like. Adding alkali or alkaline substance into the mother liquor to adjust to neutrality, heating to remove the solvent, and concentrating. The heating temperature is 50-90 deg.C, the vacuum degree is-0.01-0.09 MPa, after the mother liquor is concentrated, the second crystallization is carried out according to the above-mentioned crystallization method, also can be directly made into 18% insecticidal double water agent product produced by known method.

The method has simple process, does not need to prepare the raw material [ A], can directly adopt a [ A&HCl]fine solution or a solution prepared from the solid of the [ A&HCl]fine solution as the raw material, and has the advantages of high sulfonation yield, less side reaction, good quality and high content of the raw powder product and high powder yield. The method is suitable for technical transformation of the existing bisultap and monosultap raw pesticide production plants in China, has obvious economic benefit and is beneficial to the expansion of export.

Example 1. 1-dimethylamino-2, 3-dichloropropane hydrochloride [ A. HCl]196 g (content: 98.2%, equivalent to 1 mol) was charged into a reaction flask, 1200 ml of 80% aqueous methanol solution was added and dissolved with stirring, NaOH solution was added to adjust to neutrality at about-5 ℃, 514g of 99% sodium thiosulfate pentahydrate (equivalent to 2.05 mol) was added, the mixture was heated to 65 ℃ under neutral conditions and kept warm for 4 hours, and after sulfonation was completed, salt precipitation was removed by filtration while it was hot. And (3) dropping hydrochloric acid into the prepared sulfonation liquid while stirring and cooling to adjust the isoelectric point (PH 5.1). Adding a proper amount of seed crystal at about 28 ℃, controlling the cooling speed, continuously cooling to-10 ℃, and maintaining until the crystallization is finished. Filtering and separating, washing a filter cake with methanol for three times, and drying to obtain a raw powder product [1]; adding alkali into the mother liquor to adjust the mother liquor to be neutral, heating to evaporate methanol, concentrating and then carrying out secondary crystallization. Sulfonation yield: 96.2 percent; the content of the raw powder is as follows: 98.5 percent; powder yield: 80.9 percent.

Example 2: 320.8 g of [ A.HCl]refined water solution (the content is 60 percent, which is equivalent to 1 mol) is added into a reaction bottle, the solution is adjusted to be neutral by adding alkaline solution at about-5 ℃, 514g of 99 percent sodium thiosulfate pentahydrate (which is equivalent to 2.05 mol) is added, the solution is heated and dissolved, the solution is heated to 75 ℃ under the neutral condition, the temperature is kept for 3.5 hours, and the solution is filtered to remove salt and precipitate salt when the solution is hot. Cooling the prepared sulfonated liquid to 38 ℃, adding a proper amount of seed crystals, controlling the cooling speed, adding hydrochloric acid at about 25 ℃ to adjust the isoelectric point, continuously cooling to-10 ℃, filtering, washing a filter cake with methanol for three times, and drying to obtain a raw powder product [1]; adding alkali into the mother liquor to adjust the mother liquor to be neutral to obtain an aqueous product. Sulfonation yield: 93.8 percent; the content of the raw powder is as follows: 95.8 percent.

Claims

1. Preparation method of refined organic thiosulfate with formula [1]

(CH₃)₂NH⁺CH(CH₂SSO^- ₃)₂·1／2(Na⁺)₂·H₂O——[1]The method uses 1-dimethylamino-2, 3-dichloropropane hydrochloride as raw material, and after the thiosulfonation reaction of the raw material and sodium thiosulfate, the refined product [1]is obtained by crystallization]. The invention is characterized in that:

(1) 1-dimethylamino-2, 3-dichloropropane hydrochloride refined solution or solution prepared from solid thereof is used as a raw material, and alkali or alkaline substances are added at low temperature to adjust the solution to be neutral.

(2) Under the neutral condition, sodium thiosulfate pentahydrate is directly added to carry out the thiosulfonation reaction, and the high-concentration sulfonation stock solution is directly prepared.

(3) Under the condition of controlling temp. reduction and low-speed stirring, crystal seeds are added at proper time, and the mixture is regulated to the vicinity of isoelectric point (about pH 5.1) by using hydrochloric acid or hydrogen chloride gas or dilute sulfuric acid, etc. so as to make the crystal normally grow.

(4) And separating the crystals by adopting a centrifuge with a high separation factor, and washing the crystals by using a solvent.

(5) Under neutral conditions, the solvent in the mother liquor is removed by heating and concentrated.

2. The method of claim 1, wherein: sequentially dissolving 1-dimethylamino-2, 3-dichloropropane hydrochloride solution or a solution formed by dissolving solid of the 1-dimethylamino-2, 3-dichloropropane hydrochloride solution in an alcohol, water or alcohol-water mixed solvent, adding alkali or alkaline substances at the temperature of between 5 and 15 ℃ to adjust the solution to be neutral, adding sodium bicarbonate, heating the solution to the temperature of between 60 and 85 ℃ under the neutral condition to react for 3 to 4 hours, filtering and settling the solution while the solution is hot to separate sodium chloride serving as a byproduct, and directly preparing a high-concentration sulfonation stock solution;

3. the method of claim 1, wherein: the crystallization conditions of the sulfonation stock solution include: adding seed crystal, wherein the seed crystal temperature is 60-20 ℃; controlling the temperature reduction range to be 60-10 ℃; the cooling rate is 0.5 to 8 ℃ per hour; the stirring speed is 10-40 revolutions per minute; adjusting to isoelectric point (pH 5.1) with hydrochloric acid or hydrogen chloride gas or dilute sulfuric acid;

4. the method of claim 1, wherein: the separation factor of the centrifuge used for separating the crystal is above 1000, and the solvent for washing the crystal can be alcohol, water or alcohol-water mixed solution, preferably methanol or methanol-water solution;

5. the method of claim 1, wherein: adding alkali or alkaline substance into the mother liquor to adjust to neutrality, heating, desolventizing and concentrating. The heating temperature is 50 ℃ to 90 ℃, and the vacuum degree is-0.01 MPa to-0.09 MPa.