Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
  • C07C67/31—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by introduction of functional groups containing oxygen only in singly bound form

Definitions

• the invention relates to the technical field of preparation of herbicides, in particular to a preparation method of phenoxyacetate, and more particularly to a method for synthesizing phenoxyacetate by one-pot method.
• Chlorophenoxycarboxylic acid herbicides are the world's first commercial hormone-selective herbicides. They are environmentally friendly, have short residual periods and low toxicity to humans and other organisms, and rarely produce resistance. It is mainly used in grass crops such as corn and wheat to control dicotyledonous weeds, sedges and some malignant weeds.
• the most widely used chlorophenoxycarboxylic acid herbicides are 2,4-D.
• the molecular formula is C 8 H 6 Cl 2 O 3 , melting point 140.5 ° C, boiling point 160 ° C, pure 2,4-D can be in the form of flakes, powder, crystal powder and solid, white slightly brown, slightly phenol
• the smell is not hygroscopic and corrosive.
• the solubility in water at 25 ° C is 620 mg / L, soluble in most organic solvents such as alcohol, ether, ketone.
• Formula a is a 2,4-D structural formula.
• the technical problem to be solved by the present invention is to provide a preparation method of phenoxyacetate, and to synthesize phenoxyacetate in one pot, which greatly reduces the amount of waste water, and is energy-saving and environmentally friendly.
• the present invention provides a method for preparing phenoxyacetate, comprising the following steps:
• the solvent is one or more of DMF, DMSO, DMI and acetone;
• the catalyst is a quaternary ammonium salt or polyethylene glycol.
• the condensation reaction system of the invention is a water-free system, which eliminates the production of high-salt wastewater.
• the phenolic compound used in the present invention is preferably phenol, o-cresol or chlorophenol.
• the chlorocarboxylate has the structure of formula I:
• R 1 is preferably a C1-C5 alkylene group, more preferably a C1-C3 alkylene group, and further preferably a methylene group (-CH 2 -), a methylmethylene group (-CH(CH) 3 )-), ethylene (-CH 2 -CH 2 -), propylene (-CH 2 -CH 2 -CH 2 -) or butylene (-(CH 2 ) 4 -).
• R is preferably a C1 to C10 alkyl group or a C3 to C10 cycloalkyl group, more preferably a C1 to C8 alkyl group or a C3 to C8 cycloalkyl group, and still more preferably a methyl group, an ethyl group or a propyl group. , isopropyl, n-butyl, isobutyl, isooctyl or cyclohexyl.
• the chlorocarboxylate is chloroacetate.
• the acid binding agent is preferably one or more of sodium carbonate, potassium carbonate, and cesium carbonate.
• the catalyst is a quaternary ammonium salt, preferably benzyltriethylammonium chloride (TEBA), tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctyl One or more of ammonium chloride, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride.
• TEBA benzyltriethylammonium chloride
• TBAB tetrabutylammonium bromide
• tetrabutylammonium chloride tetrabutylammonium hydrogen sulfate
• trioctyl One or more of ammonium chloride, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride.
• the solvent is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI), and acetone.
• DMF N,N-dimethylformamide
• DMSO dimethyl sulfoxide
• DI 1,3-dimethyl-2-imidazolidinone
• acetone Preferably, it is DMF.
• the source of the above compound in the present invention is not particularly limited and may be generally commercially available.
• the invention adopts a specific catalyst to enable a phenol compound and a chlorocarboxylic acid ester to be subjected to a condensation reaction in a specific organic solvent, and the above preparation process requires only one-time injection of a phenol compound, a chlorocarboxylic acid ester, an acid binding agent, a catalyst and a solvent.
• the reactor can be prepared in one pot.
• the mass ratio of the phenolic compound to the solvent, the acid binding agent, and the catalyst is preferably 1: (1.5 to 5): (1.02 to 2): (0.1% to 1%).
• the chlorocarboxylic acid ester may be added according to a metering ratio, and the present invention is not particularly limited.
• the temperature of the condensation reaction is preferably from 40 to 160 ° C, and the reaction time is preferably from 1 to 24 hours.
• a phenoxycarboxylate compound and a hydrogencarbonate are obtained.
• the present invention provides a preparation method of phenoxyacetate, comprising the steps of: mixing a phenolic compound with a chlorocarboxylic acid ester, an acid binding agent, and a catalyst in a solvent, and performing one-pot method
• the condensation reaction gives a phenoxycarboxylate compound
• the solvent is one or more of DMF, DMSO, DMI and acetone
• the catalyst is a quaternary ammonium salt or polyethylene glycol.
• the invention realizes the anhydrous synthesis of phenoxyacetate, the whole process produces no water, participates in no water, truly achieves zero waste water discharge, greatly reduces the discharge of waste water, and can remove salt after filtration, without dehydration, energy consumption.
• the lower, one-pot method makes the reaction process simple and requires less equipment investment. Moreover, the hydrolysis of the ruthenium-chlorocarboxylic acid in the late ester hydrolysis reaction is reduced, thereby reducing the consumption of the ruthenium-chlorocarboxylic acid, and effectively avoiding the solid-liquid separation of the pure chlorophenoxyacetic acid in the prior art. The loss of the active ingredient increases the yield of the active ingredient, and the product has high purity and high yield.
• the total yield of the two steps was 94.96%; the total wastewater volume reached 523g.
• the prior art yields and water splits are far less than the one-step process provided by the present invention.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

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• 2018
  • 2018-03-19 CN CN201810225346.XA patent/CN108947824A/zh not_active Withdrawn
• 2019
  • 2019-02-27 WO PCT/CN2019/076256 patent/WO2019179286A2/fr active Application Filing
  • 2019-03-19 AR ARP190100682A patent/AR115275A1/es unknown

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