CN103980127A - Preparation method for oxyfluorfen - Google Patents

Abstract

The invention discloses a preparation method for oxyfluorfen. The preparation method comprises the following steps: (1) adding 3-chlorophenol and a proper solvent into a reaction container, then adding a catalyst, adding nitric acid drop by drop at a proper temperature, carrying out a nitration reaction and removing the solvent after completion of the reaction so as to obtain an intermediate 3-chloro-4-nitrophenol; (2) adding 3-chloro-4-nitrophenol and sodium ethoxide into a solvent, carrying out heating and a condensation reaction and removing the solvent after completion of the reaction so as to obtain an intermediate 3-ethoxy-4-nitrophenol; and (3) adding 3-ethoxy-4-nitrophenol into a proper solvent, adding 3,4-dichloro-benzotrifluoride and an acid binding agent and carrying out etherification at a proper temperature, thereby obtaining the target product oxyfluorfen after completion of etherification. The preparation method for oxyfluorfen avoids usage of extremely toxic substances, improves operation security, reduces production cost, improves product yield and reduces pollution to the environment.

Description

A kind of preparation method of oxyfluorfen

[technical field]

The present invention relates to a kind of method of preparing oxyfluorfen.

[background technology]

The diphenyl ether herbicide of the highly selective that oxyfluorfen is before a kind of bud of being developed by Rhom and Hass of the U.S., use after bud.Have that herbicidal spectrum is wide, high and low residual, the feature such as mu dosage is few of weeding ratio.Its chemical name is the chloro-α of 2-, α, and α-trifluoro p-methylphenyl-(3-oxyethyl group-4-nitrophenyl) ether, commodity are called Goal, Galigan, and structural formula is:

Both at home and abroad about the synthetic route of oxyfluorfen is reported more having:

Patent US4093446, US4353308, US4419122, US4419123 have described bis ether method: with 3,4-bis-chlorobenzotrifluorides and Resorcinol react under alkaline condition, generate the chloro-α of 2-, α, α-trifluoro p-methylphenyl-3-(chloro-α of 2-, α, α-trifluoro p-methoxyphenyl)-phenylate (abbreviation bis ether), under ethanol and the existence of excessive hydrogen potassium oxide, process and make the chloro-α of 2-, α, α-trifluoro p-methylphenyl-3-oxyethyl group phenylate, then obtains oxyfluorfen with mixed acid nitrification.The chloro-4-trifloro methyl phenol of the 2-sylvite that this technique generates there is no method utilization, thereby 3, the unit consumption of 4-bis-chlorobenzotrifluorides is high, in addition because the chloro-4-trifluoromethylbenzene of a large amount of 2-phenates containing in waste water is unstable, trifluoromethyl is easily hydrolyzed, likely produce hydrogen fluoride, produce strong impulse smell simultaneously, in addition in nitrifying process, adopt a large amount of excessive nitration mixture, have greater environmental impacts, and former medicine content is in 70% left and right, and visual appearance is poor, viscosity is large, it is dry to be difficult for, production cost is high, environmental pollution is serious.Its reaction process is as follows:

Patent US3798276, US4093446, US4358308, US4419122, US4419123 have described monoether hydroxyl protection method: obtain target product taking Resorcinol as raw material through etherificate, condensation, nitration reaction.There is the defects such as operational path is long, raw material availability is low, poor product quality, cost is high, environmental pollution is serious in this technique.Its reaction process is as follows:

Patent CN1068106 has reported a kind of single etherification method new synthetic process route: for raw material, make oxyfluorfen through monoether, condensation, nitration reaction with 3,4-, bis-chlorobenzotrifluorides and Resorcinol, ethyl sulfate, aceticanhydride etc.The consumption that this technique has 3,4-, bis-chlorobenzotrifluorides is low, the advantage that technical process is short, but its raw materials used kind is many, and adopt highly toxic substance ethyl sulfate and a large amount of excessive concentrated nitric acid, not only operational hazards coefficient is high, and synthesis yield is low, product content is low, is unsuitable for suitability for industrialized production.Its reaction process is as follows:

Patent 201010526052.4 has been reported a kind of novel dual-ether method: first carry out bis ether reaction, then pass through nitration reaction etc., and adopt the mode of multi-solvents exchange to remove impurity, product content is significantly improved.The method that it adopts and foreign literature method are roughly the same, in Resorcinol potassium salinization, adopt toluene, dimethyl sulfoxide (DMSO) mixed solvent, adopt the mode of multi-solvents exchange, distillation to remove impurity, although obtained the higher oxyfluorfen of quality, but adopt a large amount of excessive nitration mixture, and repeatedly use, the distillation of multi-solvents cause complex steps, long reaction time, yield is low, and environmental pollution is serious.Its reaction process is as follows:

[summary of the invention]

The present invention is low in order to solve prior art products yield, reaction process complexity, and production cost is high, and environmental pollution seriously waits not enough, and a kind of new synthetic method is provided.

Technical scheme of the present invention is: taking 3-chlorophenol as raw material, generate the chloro-4-nitrophenols of intermediate 3-through nitration reaction, then generate 3-oxyethyl group-4-nitrophenols through condensation reaction, last with 3,4-bis-chlorobenzotrifluorides generate oxyfluorfen through etherification reaction.Its reaction process is as follows:

The present invention includes following steps:

(1) 3-chlorophenol and suitable solvent are dropped in reaction vessel, add catalyzer, at suitable temperature, drip nitric acid, carry out nitration reaction, reacted aftertreatment and sloughed solvent and obtain the chloro-4-nitrophenols of intermediate 3-.

(2) chloro-3-4-nitrophenols and sodium ethylate are joined in solvent, heat up and carry out condensation reaction, the aftertreatment that reacts completely is sloughed solvent and is obtained intermediate 3-oxyethyl group-4-nitrophenols.

(3) 3-oxyethyl group-4-nitrophenols is joined in suitable solvent, add 3,4-, bis-chlorobenzotrifluorides and acid binding agent, at suitable temperature, carry out etherification reaction, after reacting completely, obtain target product oxyfluorfen.

In nitration reaction described in step (1), the solvent of selecting is benzene,toluene,xylene, preferentially selects toluene; The catalyzer of selecting is solid-carrying type catalyzer, and its carrier is molecular sieve, gac, and activeconstituents is Sodium Nitrite, aluminum chloride, ammonium chloride, iron(ic) chloride, and the weight ratio of catalyzer and raw material 3-chlorophenol is 0.01～0.2:1; The temperature of reaction of selecting is 50～110 DEG C.

In condensation reaction described in step (2), the solvent of selecting is ethanol, and temperature of reaction is 30～80 DEG C, and the reaction times is 2～6 hours.

In etherification reaction described in step (3), the solvent of selecting is aromatic hydrocarbon and halohydrocarbon, and temperature of reaction is 50～150 DEG C.

The above-mentioned method of preparing oxyfluorfen has following beneficial effect: 1, owing to adding composite catalyst to substitute nitration mixture directional nitrification reaction in nitration reaction, avoid the use of excessive nitration mixture, compared with prior art improve processing safety, reduce production cost, improve product yield, and greatly reduced the discharge of waste water; 2, in condensation reaction, adopt sodium ethylate to replace highly toxic substance ethyl sulfate, compared with prior art avoid the use of highly toxic substance, improve the environment of production plant, improve the security of operation, reduce the pollution to environment, and improved the total recovery of reaction, and the content of product is brought up to more than 98%, be applicable to suitability for industrialized production.

[embodiment]

Embodiment 1-2: the preparation of solid-carrying type catalyzer

1, molecular sieve adsorption Sodium Nitrite

The sodium nitrite solution of 100ml25% and 200g molecular sieve are joined with in the flask stirring, slowly stir 1h, room temperature standing adsorption 24h, filters.100 DEG C of oven dry under nitrogen protection, obtain the needed solid-carrying type catalyzer of nitration reaction.

2, charcoal absorption aluminum chloride

The aluminum trichloride solution of 100ml8% and 200g molecular sieve are joined with in the flask stirring, slowly stir 1h.Room temperature standing adsorption 24h, filters.100 DEG C of oven dry under nitrogen protection, obtain the needed solid-carrying type catalyzer of nitration reaction.

Embodiment 3-5: the preparation of oxyfluorfen

According to the listed reaction raw materials ratio of table 1,3-chlorophenol, catalyzer and toluene are joined and be furnished with thermometer, in the there-necked flask of agitator, be heated to temperature required.Slowly drip nitric acid, after detection reaction is complete, cooling, reaction solution is divided into organic phase and water, separates organic phase underpressure distillation and obtains the chloro-4-nitrophenols of intermediate 3-.

Table 1

Embodiment

3-chlorophenol

Catalyzer

Toluene

Nitric acid

Temperature of reaction

Yield (%)

3

12.8g

Molecular sieve adsorption Sodium Nitrite, 0.8g

100ml

14ml

90℃

92

4

12.8g

Charcoal absorption aluminum chloride, 0.5g

100ml

20ml

70℃

89

5

12.8g

Molecular sieve adsorption iron(ic) chloride, 0.6g

100ml

10ml

50℃

90

According to the listed reaction raw materials ratio of table 2, chloro-3-4-nitrophenols, sodium ethylate and dehydrated alcohol are joined be furnished with thermometer, in the there-necked flask of agitator, stirring is warming up to required reaction, maintain this thermotonus completely after, the reaction solution underpressure distillation obtaining is removed to ethanol, obtain target product 3-oxyethyl group-4-nitrophenols.

Table 2

Embodiment	The chloro-4-nitrophenols of 3-	Sodium ethylate	Dehydrated alcohol	Temperature of reaction	Yield (%)
						3	17.3g	8.2g	150ml	80℃	95
4	17.3g	10.2g	100ml	60℃	92
						5	17.3g	12g	200ml	40℃	85

According to the listed reaction raw materials ratio of table 3, by 3-oxyethyl group-4-nitrophenols, salt of wormwood, 3,4-bis-chlorobenzotrifluorides and toluene join be furnished with thermometer, in the there-necked flask of agitator, be warming up to desired reaction temperature, after detection reaction is complete, separate organic phase, underpressure distillation removes desolventizing and obtains product oxyfluorfen.

Claims (5)

1. one kind with 3-chlorophenol, 3,4-bis-chlorobenzotrifluorides are starting material, make the method for oxyfluorfen through nitrated, condensation, etherification reaction, it is characterized in that generating the chloro-4-nitrophenols of intermediate 3-by 3-chlorophenol and nitric acid reaction, the chloro-4-nitrophenols of 3-and sodium ethylate generate 3-oxyethyl group-4-nitrophenols through condensation reaction, 3-oxyethyl group-4-nitrophenols and 3,4-, bis-chlorobenzotrifluorides generate oxyfluorfen through etherification reaction.

2. preparation method according to claim 1, is characterized in that nitration reaction carried out under the effect of catalyzer by 3-chlorophenol and nitric acid in organic solvent.

3. nitration reaction according to claim 2, is characterized in that the catalyzer of selecting is solid-carrying type catalyzer.

4. solid-carrying type catalyzer according to claim 3, is characterized in that its carrier of selecting comprises molecular sieve, gac, and activeconstituents comprises Sodium Nitrite, aluminum chloride, ammonium chloride, iron(ic) chloride.

5. nitration reaction according to claim 2, is characterized in that the weight ratio of catalyzer and raw material 3-chlorophenol is 0.01-0.2:1.