Method for preparing herbicide

Abstract

The invention relates to a method for preparing an herbicide, and provides a method for preparing a natural herbicide, which has the advantages of mild reaction conditions, simple process, low cost and easy industrialized mass production. The method comprises the following steps of: dissolving alpha-terpineol insolvent, and adding alkali, metallic oxides and peroxides; stopping the reaction when the gas chromatographic analysis shows that the content of the alpha-terpineol is less than 0.5 percent; filtering and recovering the metallic oxides; distilling filtrate distillation to recover solvent, obtaining 1,2-epoxide; dissolving the 1,2-epoxide in the solvent, and adding acid; stopping the reaction when the gas chromatographic analysis shows that the content of the 1,2-epoxide is less than 2 percent; distilling reaction solution to recover solvent, obtaining an isomerized product of the 1,2-epoxide; dissolving the isomerized product of the 1,2-epoxide in the reaction solvent, adding alkali for stirring, and adding 2-methyl benzylchloride; stopping the reaction when the gas chromatographic analysis shows that the content of the isomerized product is less than 2 percent; pouring the reaction solution in water, adjusting the pH value of the mixed solution to neutral, and separating out organic phases; and obtaining the finished product by the water phase extraction, the combination of the organic phases, and distillation and recovery of the solvent.

Description

technical field [0001] The invention relates to a preparation method of herbicide. Background technique [0002] Cycloheptafen, also known as Ai cut, 1-methyl-4-(1-methylethyl)-2-(2-methylphenylmethoxy)-7-oxabicyclo[2,2,1 ] Heptane, (1RS, 2SR, 4SR)-1,4-oxo-p-ment-2-yl-2-methyl-benzyl ether (CAS NO 87818-31-3), belonging to cineole ) class of herbicides, which can effectively control most of the Gramineae and Cyperaceae weeds, such as barnyardgrass, bermudagrass, and special-shaped sedges. As a natural herbicide, cycloheptafen has many excellent properties and has been widely accepted in Europe and the United States, and has entered the European and Australian markets with good application results. The market is developing rapidly and there is a huge demand space . [0003] About the synthesis of cycloheptafen, there are some documents and patent reports at home and abroad, the method that adopts is: trimethylacetic acid, (soil)-terpene-4-alcohol, two (2,4-pentanedioic aci...

AI Technical Summary

Problems solved by technology

[0004] These existing synthesis methods all have deficiencies, which are mainly reflected in: 1) a large amount of toxic dichloromethane with a low boiling point is used as a solvent, which is not easy to recycle and will cause damage to the human body, and also increases the production cost; 2) in the epoxidation Use organometallic oxides as catalysts, the process is complex, difficult to recycle, and the cost is high; 3) the use of highly dangerous sodium hydride in the condensation reaction has serious safety hazards, which is not conducive to large-scale industrial operations; 4) the product The quality still needs to be improved (content1.5%)