WO2021102875A1 - 从二甲戊灵中脱去n-亚硝基化合物的方法 - Google Patents

从二甲戊灵中脱去n-亚硝基化合物的方法 Download PDF

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WO2021102875A1
WO2021102875A1 PCT/CN2019/121811 CN2019121811W WO2021102875A1 WO 2021102875 A1 WO2021102875 A1 WO 2021102875A1 CN 2019121811 W CN2019121811 W CN 2019121811W WO 2021102875 A1 WO2021102875 A1 WO 2021102875A1
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pendimethalin
reaction
nitroso compounds
hydrochloric acid
crude
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French (fr)
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钟锡君
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钟锡君
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/82—Purification; Separation; Stabilisation; Use of additives
    • C07C209/84—Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C211/00—Compounds containing amino groups bound to a carbon skeleton
    • C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
    • C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
    • C07C211/52—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring the carbon skeleton being further substituted by halogen atoms or by nitro or nitroso groups

Definitions

  • the invention belongs to the field of herbicide preparation, and relates to the preparation of pendimethalin, in particular to a method for removing N-nitroso compounds from pendimethalin.
  • Pendimethalin is an aniline herbicide developed by American Cyanamide Company (now owned by BASF).
  • the original drug is orange-yellow crystals with a melting point of 56-58°C.
  • the solubility in water is very small. It is easily soluble in chlorinated hydrocarbon and aromatic hydrocarbon solvents, and is stable to acid and alkali.
  • the current pendimethalin production process mainly uses N-(3-pentyl)-2,3-xylene amine as the raw material and concentrated nitric acid as the nitrating agent.
  • the amino N atom can easily form the N-NO product (US4136117). Therefore, there is a process of removing the nitroso group after the nitration in the production process, and the resulting product is post-treated and concentrated to give pendimethalin crude.
  • N-NO products are carcinogenic, and it is described in Adv.Cancer.Res.1967.10:163 that these N-nitroso compounds have carcinogenic effects on many animals.
  • This method usually adds sulfite (US5196585), dithionite (US4440962, US4501608), monoalkyl alcoholamine (US5405999), etc. to the reaction system to inhibit the target product from further reacting with nitric acid to produce N-nitroso Compound.
  • sulfite US5196585
  • dithionite US4440962, US4501608
  • monoalkyl alcoholamine US5405999
  • the method mainly includes two methods of steam distillation or high temperature pyrolysis to reduce the content of N-nitroso compounds in the system. Since N-nitroso compounds are unstable and have the risk of explosion when the content is high, it is mainly used to further reduce the content of N-nitroso compounds when the content of N-nitroso compounds is very low.
  • the conversion method is mainly to decompose the content of N-nitroso compounds into the target product through a chemical reaction, usually in the presence of a strong acid (HCl or HBr).
  • a strong acid usually in the presence of a strong acid (HCl or HBr).
  • sulfamic acid decomposes to produce sulfuric acid, which increases the acidity in the system and complicates the salt components in the wastewater; the organic components in the system after the use of aldehydes, ketones, acyl halides, or carbamate compounds are complicated, and the organic components formed need to be separated Impurities, ferrous chloride itself has reducing properties, and undergoes a reduction reaction with the nitro group in pendimethalin, which reduces the quality of the product.
  • hydrochloric acid used in the above conversion scheme is not well utilized, and is usually treated as wastewater, and a large amount of waste salt is generated during the treatment.
  • the object of the present invention is to provide a method for removing N-nitroso compounds from pendimethalin, which uses concentrated hydrochloric acid and ammonium chloride as an additive for denitrification , Ammonium chloride reacts with the nitrosyl chloride formed in the denitrification process to form ammonium nitrite and hydrogen chloride. Ammonium nitrite is unstable and easily decomposes nitrogen and water. The hydrogen chloride formed is dissolved in water to form hydrochloric acid without introducing organic impurities. , Does not produce salty wastewater.
  • the method for removing N-nitroso compounds from pendimethalin includes the following steps: adding hydrochloric acid and chlorine to the dichloroethane solution of the crude pendimethalin containing N-nitroso compounds after the nitration reaction is completed. Ammonium chloride and auxiliary catalyst are stirred and reacted under heating until the N-nitroso compound content in the reaction system is detected to be less than 0.05% and the reaction is stopped; the reaction liquid is post-treated, concentrated and desolventized to obtain pendimethalin product.
  • the temperature of the reaction is 78°C to 82°C, and the reaction time is 6 to 10 hours.
  • the mass concentration of the hydrochloric acid is 25% to 38%.
  • the content of N-nitroso compounds in the dichloroethane solution of the crude pendimethalin is determined by liquid chromatography, and the content is N-nitroso compound peak area/N-nitroso compound and pendimethalin peak The sum of the area usually ranges from 20 to 30%.
  • the process of removing nitroso compounds in the system of the present invention is a process in which the content of nitroso compounds in the system is continuously reduced. Therefore, N in the dichloroethane solution of the present invention -The content of nitroso compounds is ⁇ 30%.
  • the mass ratio of the crude pendimethalin to the dichloroethane in the dichloroethane solution of the crude pendimethalin is 1:1.5-5.
  • the mass of the crude pendimethalin is the total mass of the N-nitroso compound and the product pendimethalin in the solution.
  • the mass ratio of the crude pendimethalin, the concentrated hydrochloric acid, the ammonium chloride and the auxiliary catalyst in the dichloroethane solution of the crude pendimethalin is 1:0.3-1:0.04-0.2:0-0.1.
  • the auxiliary catalyst is one or a mixture of two or more of acetone, n-propionaldehyde, methyl ethyl ketone, 3-pentanone or methyl isopropyl ketone.
  • the further improvement scheme of the present invention is:
  • reaction liquid is subjected to azeotropic distillation at atmospheric pressure to recover hydrochloric acid before post-treatment.
  • the atmospheric pressure azeotropic distillation temperature is 90-100°C, and the time is 6-10h.
  • the hydrochloric acid recovered by the atmospheric distillation can be reused to remove N-nitroso compounds from pendimethalin. Furthermore, in order to ensure that the required concentration of hydrochloric acid is 25%-38% during the reaction process, When the concentration of recovered hydrochloric acid is less than 25%, the concentration of hydrochloric acid can be increased by adding 38% hydrochloric acid or hydrogen chloride gas to ensure the effect of the reaction.
  • the further improvement scheme of the present invention is:
  • the post-treatment includes alkaline washing with lye, washing with water, acid washing with acid and then washing with water.
  • the lye is a 3% to 8% sodium hydroxide solution, and the acid is a 1% to 5% hydrochloric acid solution.
  • the present invention uses concentrated hydrochloric acid and uses ammonium chloride as an additive for denitrification.
  • the ammonium chloride reacts with the nitrosyl chloride formed during the denitrification process to form ammonium nitrite and hydrogen chloride.
  • ammonium nitrite is unstable and easily decomposes
  • the hydrogen chloride formed by nitrogen and water dissolves in water to form hydrochloric acid without adding other components, introducing organic impurities, and producing salty wastewater.
  • the present invention uses azeotropic distillation to recover hydrochloric acid to achieve the following: 1) recovering hydrochloric acid reduces the acidity of the organic phase in the reaction system, reduces the formation of waste salts in the production system, and also reduces the discharge of waste acid water; 2) extends the reaction time, While the hydrochloric acid is recovered by azeotropic distillation, N-nitroso compounds continue to be converted into pendimethalin, so that the content of N-nitroso compounds in the resulting product is lower, which can reach below 500 ppm. 3) The hydrochloric acid recovered by atmospheric distillation can be It is reused in the pendimethalin production process to remove N-nitroso compounds again, thereby realizing the recycling of hydrochloric acid.
  • the concentration of hydrochloric acid can be increased by adding 38% hydrochloric acid or hydrogen chloride gas to ensure the effect of the reaction.
  • aldehydes and ketones are added as auxiliary catalysts. Because aldehydes and ketones react with the nitrosyl chloride formed by the reaction, the concentration of nitroso compounds in the system is reduced, thereby promoting the reduction of N-nitroso compounds in the final product. Ensure product quality.
  • the organic phase obtained by layering Separate the organic phase obtained by layering, add 68-70% nitric acid dropwise, control the temperature of the dropwise addition to 50-60°C, after the addition, keep the temperature for 30 minutes, separate the nitric acid (concentration 30-40%) layer, wash the organic phase with water, and layer Water-phase inlet water treatment system.
  • the organic phase obtained by layering is a dichloroethane solution of the crude pendimethalin, and the content of N-nitroso compounds is less than or equal to 30% by HPLC analysis.
  • the distillation time is about 6h
  • the organic phase after distillation is washed with 100g 5% NaOH solution, 100g water, 100g 2% hydrochloric acid, 100g water, and then concentrated at normal pressure to recover the solvent to the internal temperature to 135
  • 132 g of pendimethalin product was obtained by vacuum extraction.
  • the content is 98.6%.
  • the content of N-nitroso compounds is 380 ppm.
  • the distillation time is about 10h
  • the organic phase after distillation is washed with 100g 5% NaOH solution, 100g water, 100g 2% hydrochloric acid, 100g water, and after atmospheric pressure concentration to recover the solvent, vacuum desolventizes to obtain dimethylformaldehyde.
  • the content is 98.9%.
  • the content of N-nitroso compounds is 290 ppm.
  • the distillation time is about, and the distillation time is about 9h.
  • the organic phase after distillation is washed with 100g 5% NaOH solution, 100g water, 100g 2% hydrochloric acid, 100g water, and after normal pressure concentration to recover the solvent, vacuum 321 g of pendimethalin product was obtained after desolvation.
  • the content is 97.2%.
  • the content of N-nitroso compounds is 91 ppm.
  • the obtained organic phase was kept at 45-55°C, washed with 100g 5% NaOH solution, 100g water, 100g 2% hydrochloric acid, 100g water, and concentrated under normal pressure to recover the solvent, and then vacuum desolventized to obtain 125g product.
  • the content is 95.2%, HPLC: 97.1%.
  • N-nitroso compounds 290 ppm.
  • the obtained organic phase was kept at 45-55°C, washed with 100g 5% NaOH solution, 100g water, 100g 2% hydrochloric acid, 100g water, and concentrated under normal pressure to recover the solvent, and vacuum desolventized to obtain 120g product.
  • the content is 95.4%, HPLC: 97.2%.
  • N-nitroso compounds 96 ppm.

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  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

公开了一种从二甲戊灵中脱去N-亚硝基化合物的方法，包括向硝化反应完成后的、含有N-亚硝基化合物的二甲戊灵的二氯乙烷溶液中加入盐酸、氯化铵以及辅助催化剂，升温反应，检测反应体系中N-亚硝基化合物含量小于0.05％时停止反应，然后经后处理得二甲戊灵产品。该方法以氯化铵作为脱亚硝基的添加剂，不引入有机杂质，不产生含盐废水。

Description

从二甲戊灵中脱去N-亚硝基化合物的方法 技术领域
本发明属于除草剂制备领域，涉及二甲戊灵的制备，特别涉及从二甲戊灵中脱去N-亚硝基化合物的方法。
背景技术
二甲戊灵(pendimethalin)由美国氰胺公司(现归属巴斯夫公司)开发的苯胺类除草剂。原药为橙黄色结晶，熔点为56～58℃在水中的溶解度很小，易溶于氯代烃和芳香烃溶剂，对酸碱稳定。
目前二甲戊灵生产工艺主要以N-(3-戊基)-2,3-二甲苯胺为原料，以浓硝酸作为硝化剂而来。在硝化过程中氨基N原子很容易形成N-NO化产物(US4136117)，因此在生产过程中在硝化后有一个脱除亚硝基的过程，所得产品经后处理浓缩得二甲戊灵粗品。值得注意的是，N-NO化产物具有致癌性，在Adv.Cancer.Res.1967.10:163中记载了这些N-亚硝基化合物对许多动物具有致癌作用。随后不久在Nature.1970.225:21中又被证实这些N-亚硝基化合物对人体也有致癌作用。在《化学检验》Vol.37.No.4,Apr.2001中记载了由于此工艺中产生的N-亚硝基化合物很难挥发，且在土壤中不易降解，易滞留在土壤中被植物吸收等特点。
当前常见的降低N-亚硝基化合物的含量的方法有三种，分别是：
(1)减弱硝化试剂活性法
此方法通常是在反应体系中加入亚硫酸盐(US5196585)、连二亚硫酸盐(US4440962、US4501608)、单烷基醇胺(US5405999)等来抑制目标产物进一步与硝酸反应产生N-亚硝基化合物。但是上述过程的效果不显著，在硝化过程中仍有10％以上的N-亚硝基化合物生成。
(2)物理分离法
该方法主要包括通过水蒸气蒸馏或高温热解两种方法降低体系中N-亚硝基化合物的含量。由于N-亚硝基化合物不稳定，含量高时具有爆炸的风险，因此主要用于N-亚硝基化合物的含量很低时进一步降低N-亚硝基化合物的含量。
(3)转化法
转化法主要是是通过化学反应将N-亚硝基化合物的含量分解转化为目标产物，通常在强酸(HCl或HBr)存在下进行，反应方程式如下：
Figure PCTCN2019121811-appb-000001
由于该反应是可逆反应，为提高转化率，使反应完全，通常向反应体系中加入氨基磺酸(US5405999)、醛酮(US4226789)、酰基卤化物(US4675445)、或氨基甲酸酯类化合物(US4537992、US4970343)、氯化亚铁(CN101070287)等。这些添加剂在降低N-亚硝基化合物含量的同时，也使得体系的成分复杂，增加后处理难度。如氨基磺酸分解产生硫酸，增加体系中酸度，并使废水中盐成分复杂化；醛酮、酰基卤化物、或氨基甲酸酯类化合物使用后体系中有机成分复杂化，需要分离出所形成的有机杂质，氯化亚铁本身就有还原性质，与产物二甲戊灵中的硝基发生还原反应，降低产品质量。
而且，上述转化方案所使用的盐酸并没有得到很好的利用，通常作为废水处理，处理过程中产生大量废盐。
发明内容
针对现有技术的不足，本发明的目的在于提供一种从二甲戊灵中脱去N-亚硝基化合物的方法，该方法采用在浓盐酸下，以氯化铵作为脱亚硝的添加剂，氯化铵与脱亚硝过程形成的亚硝酰氯反应形成亚硝酸铵以及氯化氢，其中亚硝酸铵不稳定很容易分解出氮气与水，所形成的氯化氢溶于水成盐酸，不引入有机杂质，不产生含盐废水。
本发明是通过以下技术方案实现的：
从二甲戊灵中脱去N-亚硝基化合物的方法，包括如下步骤：向硝化反应完成后含有N-亚硝基化合物的二甲戊灵粗品的二氯乙烷溶液中加入盐酸、氯化铵 以及辅助催化剂，加热下搅拌反应，至检测反应体系中N-亚硝基化合物含量小于0.05％时停止反应；反应液经后处理后，浓缩脱溶，得二甲戊灵产品。
所述反应的温度为78℃～82℃，所述反应时间为6～10h。
所述盐酸的质量浓度为25％～38％。
所述二甲戊灵粗品的二氯乙烷溶液中N-亚硝基化合物含量由液相色谱测定，含量为N-亚硝基化合物峰面积/N-亚硝基化合物与二甲戊灵峰面积的和，范围通常在20～30％，然而本发明脱除体系中亚硝基化合物的过程是体系中亚硝基化合物含量不断降低的过程，因此本发明所述二氯乙烷溶液中N-亚硝基化合物的含量≤30％。
所述二甲戊灵粗品的二氯乙烷溶液中二甲戊灵粗品与二氯乙烷的质量比为1:1.5～5。
所述二甲戊灵粗品的质量，为溶液中N-亚硝基化合物与产品二甲戊灵的总质量。
所述二甲戊灵粗品的二氯乙烷溶液中的二甲戊灵粗品、浓盐酸、氯化铵以及辅助催化剂的质量比为1:0.3～1:0.04～0.2：0～0.1。
所述辅助催化剂为丙酮、正丙醛、甲乙酮、3-戊酮或甲基异丙基酮中的一种或两种以上混合。
本发明的进一步改进方案为：
所述反应液常压共沸蒸馏回收盐酸后再去后处理。
所述常压共沸蒸馏温度为90-100℃，时间为6～10h。
所述常压蒸馏所回收的盐酸可重复利用于从二甲戊灵中脱去N-亚硝基化合物，更进一步的，在反应过程中为保证盐酸所需的浓度在25％-38％，当回收的盐酸浓度低于25％时，可通过加入38％盐酸或氯化氢气体来提高盐酸浓度，以保证反应的效果。
本发明的更进一步改进方案为：
所述后处理包括碱液碱洗、水洗、酸液酸洗再水洗。
所述碱液为3％～8％的氢氧化钠溶液，所述酸液为1％～5％的盐酸溶液。
本发明的有益效果为：
本发明采用在浓盐酸下，以氯化铵作为脱亚硝的添加剂，氯化铵与脱亚硝过程形成的亚硝酰氯反应形成亚硝酸铵以及氯化氢，其中亚硝酸铵不稳定很容易分解出氮气与水，所形成的氯化氢溶于水成盐酸，不增加其他成分，不会引入有机杂质，也不产生含盐废水。
本发明通过共沸蒸馏回收盐酸的方式，达到如下：1)回收盐酸降低反应体系中有机相的酸度，减少生产体系中废盐的形成，也减少废酸水的排放；2)延长反应时间，共沸蒸馏回收盐酸的同时，N-亚硝基化合物继续转化为二甲戊灵，使得所得产品的N-亚硝基化合物含量更低，可达到500ppm以下,3)常压蒸馏回收的盐酸可重复利用于二甲戊灵生产工艺中，再次脱除N-亚硝基化合物，从而实现盐酸的循环利用。为保证盐酸所需的浓度在25％-38％，当盐酸浓度低于25％时，可通过加入38％盐酸或氯化氢气体来提高盐酸浓度，以保证反应的效果。
本发明添加醛酮类为辅助催化剂，由于醛酮类试剂通过与反应形成的亚硝酰氯反应，减低体系中亚硝基化合物的浓度，从而推动最终产品中的N-亚硝基化合物含量降低，保证产品质量。
具体实施方式
实施例1
制备二甲戊灵
戊胺加入1,2-二氯乙烷溶解，加热至50-60℃，滴加35-45％硝酸，控制反应温度50-60℃，分层得浓度1-4％稀硝酸进废水处理系统。
分层所得有机相，滴加68-70％硝酸，控制滴加温度50-60℃，加毕，保温反应30分钟，分出硝酸(浓度30-40％)层，有机相加水洗，分层水相进水处理系统。分层所得有机相为二甲戊灵粗品的二氯乙烷溶液，经HPLC分析，其中N-亚硝基化合物的含量小于等于30％。
脱N-亚硝基化合物
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液300g(其中含有二甲戊 灵粗品100g，N-亚硝基化合物含量为23％),加入氯化铵15g,30％盐酸75g,升温至80℃反应10小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。向反应体系中加入30g水，搅拌后静置分层，分出有机相，有机相依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂至内温至135℃后，真空脱溶得二甲戊灵产品85g。含量96.6％。N-亚硝基化合物含量828ppm。
实施例2
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液300g(其中含有二甲戊灵粗品100g，N-亚硝基化合物含量为28％),加入氯化铵6g,25％盐酸30g,升温至82℃反应6小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。向反应体系中加入60g水，搅拌后静置分层，分出有机相，有机相依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂至内温至130℃后，真空脱溶得二甲戊灵产品90g。含量97.8％。N-亚硝基化合物含量1200ppm。
实施例3
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液375g(其中含有二甲戊灵粗品150g，N-亚硝基化合物含量为20％),加入氯化铵6g,25％盐酸90g,升温至78℃反应6小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。反应装置接分水器，常压蒸馏至内温升至100℃，至分水器中不再有水产生，结束蒸馏(在蒸馏溶剂过程中，通过分水器不断分出水，并将有机溶剂返回蒸馏装置中)，蒸馏时间约为6h，蒸馏后的有机相依次以100g5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂回收溶剂至内温至135℃后，真空脱溶得二甲戊灵产品132g。含量98.6％。N-亚硝基化合物含量380ppm。
实施例4
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液500g(其中含有二甲戊灵粗品100g，N-亚硝基化合物含量为5％),加入氯化铵6g,25％盐酸30g,升 温至78℃反应8小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。反应装置接分水器，常压蒸馏至内温升至100℃，至分水器中不再有水产生，结束蒸馏(在蒸馏溶剂过程中，通过分水器不断分出水，并将有机溶剂返回蒸馏装置中)，蒸馏时间约10h，蒸馏后的有机相依次以100g5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂后，真空脱溶得二甲戊灵产品93g。含量98.9％。N-亚硝基化合物含量290ppm。
实施例5
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液1650g(其中含有二甲戊灵粗品330g，N-亚硝基化合物含量为30％),加入氯化铵33g,3-戊酮33g，32％盐酸330g,升温至80℃反应6小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。常压蒸馏至内温升至100℃，至分水器中不再有水产生，结束蒸馏(在蒸馏溶剂过程中，通过分水器不断分出水，并将有机溶剂返回蒸馏装置中)，蒸馏时间约，蒸馏时间约9h，蒸馏后的有机相依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂后，真空脱溶得二甲戊灵产品290g。含量96.5％。N-亚硝基化合物含量83ppm。
实施例6
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液(650g，其中含有二甲戊灵粗品330g，N-亚硝基化合物含量为12％)中,加入氯化铵66g,正丙醛12g，32％盐酸280g,升温至80℃反应6小时，取样，经HPLC分析，反应液中N-亚硝基化合物的含量小于0.05％，停止反应。反应装置接分水器，常压蒸馏至内温升至100℃，至分水器中不再有水产生，结束蒸馏(在蒸馏溶剂过程中，通过分水器不断分出水，并将有机溶剂返回蒸馏装置中)，蒸馏时间约，蒸馏时间约9h，蒸馏后的有机相依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗后，常压浓缩回收溶剂后，真空脱溶得二甲戊灵产品321g。含量97.2％。N-亚硝基化合物含量91ppm。
实施例7：
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液中(350g,其中含有二甲戊灵粗品150g，N-亚硝基化合物含量为28％，)中,加入氯化铵15g,实施例3回收的盐酸(25％)30g,浓盐酸(38％)15g,升温至78-82℃，至反应完成(HPLC：N-亚硝基化合物<0.05％),停止反应。反应装置接分水器，常压蒸馏共沸回收盐酸，有机层分出后回入蒸馏釜中，水层测盐酸浓度在21％，计27g，蒸馏时间约5小时。
所得有机相保温45-55℃下，依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗，常压浓缩回收溶剂后，真空脱溶得产品125g。含量95.2％,HPLC:97.1％。N-亚硝基化合物：290ppm。
实施例8：
向硝化反应完成后的二甲戊灵粗品的二氯乙烷溶液中(350g,其中含有二甲戊灵粗品150g，N-亚硝基化合物含量为25％),加入氯化铵15g,实施例7回收的盐酸(21％)27g,浓盐酸(38％)18g,3-戊酮5g,升温至78-82℃，至反应完成(HPLC：N-亚硝基化合物<0.05％),停止反应。反应装置接分水器，常压蒸馏共沸回收盐酸，有机层分出后回入蒸馏釜中，水层测盐酸浓度在25％，计24g，蒸馏时间约6小时。
所得有机相保温45-55℃下，依次以100g 5％NaOH溶液洗，100g水洗，100g 2％盐酸洗，100g水洗，常压浓缩回收溶剂后，真空脱溶得产品120g。含量95.4％,HPLC:97.2％。N-亚硝基化合物：96ppm。

Claims (10)

  1. 从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于，包括如下步骤：向硝化反应完成后含有N-亚硝基化合物的二甲戊灵粗品的二氯乙烷溶液中加入盐酸、氯化铵以及辅助催化剂，加热下搅拌反应，至检测反应体系中N-亚硝基化合物含量小于0.05％时停止反应；反应液经后处理后，浓缩脱溶，得二甲戊灵产品。
  2. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述反应的温度为78℃～82℃，所述反应时间为6～10h。
  3. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述反应液常压共沸蒸馏回收盐酸后再去后处理。
  4. 根据权利要求3所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述常压共沸蒸馏的反应器内温度为90-100℃。
  5. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述盐酸的质量浓度为25％～38％。
  6. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述二甲戊灵粗品的二氯乙烷溶液中N-亚硝基化合物的质量含量小于等于30％，所述二甲戊灵粗品的二氯乙烷溶液中二甲戊灵粗品与二氯乙烷的质量比为1:1.5～5。
  7. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述二甲戊灵粗品的二氯乙烷溶液中的二甲戊灵粗品、浓盐酸、氯化铵以及辅助催化剂的质量比为1:0.3～1:0.04～0.2：0～0.1。
  8. 根据权利要求1或7任意一项所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述辅助催化剂为丙酮、正丙醛、甲乙酮、3-戊酮或甲基异丙基酮中的一种或两种以上混合。
  9. 根据权利要求1所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述后处理包括碱液碱洗、水洗、酸液酸洗再水洗。
  10. 根据权利要求7所述的从二甲戊灵中脱去N-亚硝基化合物的方法，其特征在于：所述碱液为3％～8％的氢氧化钠溶液，所述酸液为1％～5％的盐酸溶液。
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