Dicamba preparation process

Abstract

The invention belongs to the technical field of herbicide dicamba preparation and relates to a dicamba preparation process. The dicamba preparation process includes steps: taking benzene as a raw material to generate 1,2,4-trichlorobenzene through directional chlorination, catalysis, re-chlorination and rectification; hydrolyzing the 1,2,4-trichlorobenzene to generate a mixture of 2,5-dichlorophenol and 2,4-dichlorophenol, and separating and purifying to obtain 2,5-dichlorophenol; using the 2,5-dichlorophenol to prepare 3,6-dichlorosalicylic acid; subjecting the 3,6-dichlorosalicylic acid to methylation, saponification, acidification and the like to obtain dicamba. By optimization of technical steps and parameters, the whole dicamba preparation process has advantages of simplicity, low cost, high yield, high selectivity, remarkable reduction of wastewater and increase of equipment utilization rate.

Description

technical field

[0001] The invention relates to a preparation process of a herbicide, in particular to a preparation process of dicamba, and belongs to the technical field of preparation of the herbicide dicamba. Background technique

[0002] Dicamba is a benzoic acid herbicide, which has systemic conduction effect and has a significant control effect on annual and perennial broad-leaved weeds. Dicamba is used for post-emergence spraying, and the agent can be quickly absorbed by the leaves, stems and roots of weeds , conducts upward and downward through the phloem, and is mostly concentrated in the meristem and the part with vigorous metabolic activity, hindering the normal activity of plant hormones, thereby causing them to die. Poaceae plants can quickly metabolize and decompose the drug after absorbing it to make it ineffective, so they show strong drug resistance. It is relatively safe for grass crops such as wheat, corn, millet, and rice. Dicamba disappears after being...

Examples

Embodiment 1

[0069] A preparation process of dicamba, comprising the following process steps:

[0070] A. Directional chlorination

[0071] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 1.8:1;

[0072] B. Catalytic treatment

[0073] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0074] C. Rechlorination and rectification

[0075] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is 0.5:1; after the obtained mixture is rectified, the 1,2,4-trichlorobenzene product and the unreacted dichlorobenzene mixture are obtained respectively; the dichlorobe...

Embodiment 2

[0086] A preparation process of dicamba, comprising the following process steps:

[0087] A. Directional chlorination

[0088] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 2.0:1;

[0089] B. Catalytic treatment

[0090] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0091] C. Rechlorination and rectification

[0092] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is The ratio is 1.5:1; after rectification of the obtained mixture, 1,2,4-trichlorobenzene product and unreacted dichlorobenzene mixture are obtained respectively; the d...

Embodiment 3

[0103] A preparation process of dicamba, comprising the following process steps:

[0104] A. Directional chlorination

[0105] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 2.2:1;

[0106] B. Catalytic treatment

[0107] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0108] C. Rechlorination and rectification

[0109] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is The ratio is 2:1; after rectification of the obtained mixture, the 1,2,4-trichlorobenzene product and the unreacted dichlorobenzene mixture are obtained respectively;...

technical field

[0001] The invention relates to a preparation process of a herbicide, in particular to a preparation process of dicamba, and belongs to the technical field of preparation of the herbicide dicamba. Background technique

[0002] Dicamba is a benzoic acid herbicide, which has systemic conduction effect and has a significant control effect on annual and perennial broad-leaved weeds. Dicamba is used for post-emergence spraying, and the agent can be quickly absorbed by the leaves, stems and roots of weeds , conducts upward and downward through the phloem, and is mostly concentrated in the meristem and the part with vigorous metabolic activity, hindering the normal activity of plant hormones, thereby causing them to die. Poaceae plants can quickly metabolize and decompose the drug after absorbing it to make it ineffective, so they show strong drug resistance. It is relatively safe for grass crops such as wheat, corn, millet, and rice. Dicamba disappears after being...

Examples

Embodiment 1

[0069] A preparation process of dicamba, comprising the following process steps:

[0070] A. Directional chlorination

[0071] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 1.8:1;

[0072] B. Catalytic treatment

[0073] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0074] C. Rechlorination and rectification

[0075] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is 0.5:1; after the obtained mixture is rectified, the 1,2,4-trichlorobenzene product and the unreacted dichlorobenzene mixture are obtained respectively; the dichlorobe...

Embodiment 2

[0086] A preparation process of dicamba, comprising the following process steps:

[0087] A. Directional chlorination

[0088] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 2.0:1;

[0089] B. Catalytic treatment

[0090] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0091] C. Rechlorination and rectification

[0092] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is The ratio is 1.5:1; after rectification of the obtained mixture, 1,2,4-trichlorobenzene product and unreacted dichlorobenzene mixture are obtained respectively; the d...

Embodiment 3

[0103] A preparation process of dicamba, comprising the following process steps:

[0104] A. Directional chlorination

[0105] Passing chlorine gas into benzene, under the action of a catalyst, directional chlorination to obtain a mixture of p-dichlorobenzene and o-dichlorobenzene; the ratio of the amount of chlorine gas to benzene is 2.2:1;

[0106] B. Catalytic treatment

[0107] Add a Lewis acid catalyst to the p-dichlorobenzene and o-dichlorobenzene mixture obtained in step A for processing;

[0108] C. Rechlorination and rectification

[0109] Chlorine gas is passed into the mixed solution obtained by catalytic treatment in step B, and chlorination is obtained to obtain a mixture of 1,2,4-trichlorobenzene, p-dichlorobenzene and o-dichlorobenzene; the mass ratio of the chlorine gas to the mixed solution is The ratio is 2:1; after rectification of the obtained mixture, the 1,2,4-trichlorobenzene product and the unreacted dichlorobenzene mixture are obtained respectively;...