CN110776405A - Synthetic method of flonicamid intermediate - Google Patents

Abstract

The invention relates to a synthetic method of flonicamid intermediate, which is characterized by comprising the following steps: (1) adding dichloromethane and pyridine into a reaction kettle, and controlling the mass ratio of the dichloromethane to the pyridine to be 4-5: 1, cooling to below 10 ℃, dropwise adding trifluoroacetic acid, and controlling the mass ratio of the trifluoroacetic acid to the pyridine to be 0.7-0.8: 1; (2) cooling the reaction kettle to below-5 ℃, dropwise adding vinyl ether, and controlling the mass ratio of the vinyl ether to the pyridine to be 0.4-0.5: 1; (3) cooling the reaction kettle to below-5 ℃, dropwise adding methylsulfonyl chloride, and controlling the mass ratio of the methylsulfonyl chloride to the pyridine to be 0.7-0.8: reacting at the temperature of 1, 10-15 ℃ for 2-4h to generate trifluoroacetic acid vinyl ethyl ether serving as a flonicamid intermediate; (4) washing with water and 2% phosphoric acid sequentially. The invention has the advantages that: by adjusting the dripping sequence of the vinyl ethyl ether, the temperature of the early reaction is improved, the energy consumption is saved, the reaction time is reduced, and the yield is improved; the reaction is carried out under the normal pressure state, and the reaction is safe.

Description

Synthetic method of flonicamid intermediate

Technical Field

The invention belongs to the technical field of chemical production, relates to the technical field of flonicamid production, and particularly relates to a synthetic method of a flonicamid intermediate.

Background

The flonicamid is a novel low-toxicity pyridine amide insect growth regulator pesticide, has a very wide prospect market under the national policy of replacing phosphorus-containing and high-toxicity pesticides, and has the problems of low reaction requirement temperature, high energy consumption and low conversion rate in the production process of trifluoroacetic acid-based vinyl ether at present, so that the technical research and optimization of the product have important significance on the development of enterprises and local economy.

Disclosure of Invention

The invention aims to solve the problem of low product conversion rate in the prior art, and provides a synthetic method of a flonicamid intermediate (trifluoroacetic acid-based vinyl ethyl ether).

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a synthetic method of flonicamid intermediate is characterized by comprising the following steps:

(1) adding dichloromethane and pyridine into a reaction kettle, and controlling the mass ratio of the dichloromethane to the pyridine to be 4-5: 1, cooling to below 10 ℃, then dropwise adding trifluoroacetic acid, and controlling the mass ratio of the trifluoroacetic acid to the pyridine to be 0.7-0.8: 1;

(2) cooling the temperature in the reaction kettle to below-5 ℃, continuously dropwise adding vinyl ethyl ether into the reaction kettle, and controlling the mass ratio of the vinyl ethyl ether to the pyridine to be 0.4-0.5: 1;

(3) cooling the temperature in the reaction kettle to be below-5 ℃, then dropwise adding methylsulfonyl chloride to reduce the binding energy of a C-O bond, and controlling the mass ratio of the methylsulfonyl chloride to the pyridine to be 0.7-0.8: 1, controlling the reaction temperature to be 10-15 ℃, and reacting for 2-4h to generate trifluoroacetic acid vinyl ether serving as a flonicamid intermediate;

(4) and then sequentially washing the trifluoroacetyl vinyl ether by using water and 2% phosphoric acid, wherein the volume ratio of the washing liquid to the trifluoroacetyl vinyl ether is 5-8: 1.

The boiling point of the vinyl ether is lower than 35 ℃, the vinyl ether is added before the trifluoroacetic acid is added, and the temperature of a reaction system is required to be-5 ℃ so as to ensure that the vinyl ether can not volatilize due to reaction heat; according to the invention, the reaction temperature in the early stage is increased to-5-0 ℃ by changing the dropping sequence of the reactant vinyl ethyl ether (the original addition before trifluoroacetic acid is adjusted to the addition after trifluoroacetic acid), so that the reaction time and energy consumption are greatly reduced, and the yield of the product is increased from 200% to 220%.

The invention has the advantages that: by adjusting the dripping sequence of the vinyl ethyl ether, the temperature of the early reaction is improved, the energy consumption is saved, the reaction time is reduced, and the yield is improved; the reaction is carried out under normal pressure without high pressure and high temperature, and the reaction is safe.

Detailed Description

A synthetic method of a flonicamid intermediate comprises the following specific implementation steps:

example 1

(1) Adding 800L of dichloromethane and 290 Kg of pyridine into a reaction kettle, cooling to-5 ℃, and then dropwise adding 205 Kg of trifluoroacetic acid, wherein the temperature of the reaction kettle is controlled to be-5-0 ℃;

(2) continuously dropwise adding 130 Kg of vinyl ether into the reaction kettle, and controlling the temperature of the reaction kettle to be-5-0 DEG C

(3) Then, 208 Kg of methylsulfonyl chloride is dripped to reduce the binding energy of the C-O bond;

(4) controlling the reaction temperature to be 12 ℃, and reacting for 4 hours to generate trifluoroacetic acid vinyl ether as a flonicamid intermediate;

(5) adding trifluoroacetic acid-based vinyl ether and 650L of water into a reaction kettle, washing the trifluoroacetic acid-based vinyl ether with the water, retaining a lower-layer organic phase, and removing three wastes from a water phase;

(6) adding 2% phosphoric acid 650L and an organic phase 950L into a reaction kettle, washing with phosphoric acid, removing three wastes from a water phase, and leaving a layer of organic phase, namely the intermediate trifluoroacetyl vinyl ether 950L.

Comparative example 1

(1) Adding 890L of dichloromethane and 290 Kg of pyridine into the reaction kettle, cooling to-10 ℃,

(2) continuously dropwise adding 130 Kg of vinyl ether into the reaction kettle, cooling the reaction kettle to-10 ℃, and then dropwise adding 205 Kg of trifluoroacetic acid;

(3) cooling the temperature in the reaction kettle to-5 ℃, and then dropwise adding 208 Kg of methylsulfonyl chloride;

(4) controlling the reaction temperature to be 12 ℃, and reacting for 6 hours to generate trifluoroacetic acid vinyl ether as a flonicamid intermediate;

(5) adding trifluoroacetic acid-based vinyl ether and 650L of water into a reaction kettle, washing the trifluoroacetic acid-based vinyl ether with the water, retaining a lower-layer organic phase, and removing three wastes from a water phase;

(6) adding 650L of 2% phosphoric acid and 900L of organic phase into a reaction kettle, washing with phosphoric acid, removing three wastes from a water phase, and leaving a layer of organic phase, namely 900L of intermediate trifluoroacetyl vinyl ether.

The relevant comparison data is shown in the following table:

Claims (1)

1. a synthetic method of flonicamid intermediate is characterized by comprising the following steps:

(1) adding dichloromethane and pyridine into a reaction kettle, and controlling the mass ratio of the dichloromethane to the pyridine to be 4-5: 1, cooling to below 10 ℃, then dropwise adding trifluoroacetic acid, and controlling the mass ratio of the trifluoroacetic acid to the pyridine to be 0.7-0.8: 1;

(2) cooling the temperature in the reaction kettle to below-5 ℃, continuously dropwise adding vinyl ethyl ether into the reaction kettle, and controlling the mass ratio of the vinyl ethyl ether to the pyridine to be 0.4-0.5: 1;

(3) cooling the temperature in the reaction kettle to be below-5 ℃, then dropwise adding methylsulfonyl chloride to reduce the binding energy of a C-O bond, and controlling the mass ratio of the methylsulfonyl chloride to the pyridine to be 0.7-0.8: 1, controlling the reaction temperature to be 10-15 ℃, and reacting for 2-4h to generate trifluoroacetic acid vinyl ether serving as a flonicamid intermediate;

(4) and then sequentially washing the trifluoroacetyl vinyl ether by using water and 2% phosphoric acid, wherein the volume ratio of the washing liquid to the trifluoroacetyl vinyl ether is 5-8: 1.