CN105837402A - Preparation method for 2,4-dichloro-5-bromotoluene - Google Patents

Abstract

The invention discloses a preparation method for 2,4-dichloro-5-bromotoluene, which belongs to the field of chemical synthesis. The preparation method comprises the following steps: with 2,4-dichlorophenol as a raw material, adding phosphorus oxychloride for esterification; then adding carbon tetrachloride and formaldehyde for hydrolysis; adding anhydrous ethanol for reflux and carrying out rotary evaporation so as to obtain 2,4-dichloro-5-nitrophenol; then mixing 2,4-dichloro-5-nitrophenol with toluene and calcium carbonate powder so as to obtain 2,4-dichloro-5-nitrotoluene; and after completion of the reaction, adding polyethylene glycol and bromine liquid to obtain an organic phase and subjecting the organic phase to concentration under reduced pressure so as to obtain 2,4-dichloro-5-bromotoluene.

Description

A kind of preparation method of the 2,4-bis-bromo-toluene of chloro-5-

Technical field

The invention discloses one 2, the preparation method of the bromo-toluene of the chloro-5-of 4-bis-, belong to the field of chemical synthesis.

Background technology

2,4-bis-chloro-5-nitrophenol is to synthesize in the middle of the key of multiple herbicide (as oxadiazon, rice think to reach) Body, its synthesis is domestic so far without open report.Owing to the direct nitrification of 2,4 dichloro phenol obtains the chloro-6-of 2,4-bis- Nitrophenol, therefore frequently with first by 2,4-chlorophenesic acid nitrification again after protection, hydrolysis prepares this compound.

Protective agent has two effects: first protection phenol is in case being oxidized by nitric acid, furthermore changes 2,4-dichloro The locating rule of phenol, obtains 5 nitrated in position products.Protection group uses such as methylchloroformate, phosgene, trichlorine Change phosphorus etc..

Summary of the invention

The present invention provides the preparation of a kind of 2,4-bis-bromo-toluene of chloro-5-that a kind of reaction condition is gentle, yield is high The synthetic method of method.

For reaching above-mentioned purpose, one 2 of the present invention, the synthetic route of the preparation method of the bromo-toluene of the chloro-5-of 4-bis- For:

The building-up process of the 2,4-bis-bromo-toluene of chloro-5-that the present invention relates to comprises the following steps:

(1) first weigh the 2 of 50～70g, 4-chlorophenesic acid in 1000mL there-necked flask, then in bottle add 25～ The phosphorus oxychloride of 40g, puts into there-necked flask in water-bath, and liter high-temperature, to 65～75 DEG C, is maintained at this temperature Lower stirring, stirs 50～60min, carries out esterification, after reaction terminates, adds 150～200mL in bottle Carbon tetrachloride, the formaldehyde of 80～120mL, and rise high-temperature and be stirred hydrolysis to 80～90 DEG C, After stirring 1～2h, the mixed liquor in bottle is added the dehydrated alcohol of gross mass 60%, continue at 80～90 DEG C Under reflux, backflow 2～3h after, the solution in bottle is carried out rotary evaporation, the solid obtained is 2,4- Two chloro-5-nitrophenols；

(2) taking 15～20g2, chloro-5 nitrophenols of 4-bis-are in three mouthfuls of burnings of the 500mL equipped with agitator and thermometer In Ping, flask is put in water-bath, and rises high-temperature to 60～80 DEG C, backward bottle in add 150～170mL Toluene, be stirred 40～50min with magnetic stirring apparatus, stirring is warming up to 60～70 DEG C after terminating again, to Add the calcium carbonate powder of 25～30g in Ping, and proceed stirring reaction and 2～3h obtain 2, chloro-5 nitre of 4-bis- Base toluene；

(3), after above-mentioned reaction terminates, in bottle, add the Polyethylene Glycol of 5～7g, and bath temperature is warming up to boiling Rise, and be stirred with the rotating speed of 500～600r/min with magnetic stirring apparatus, after stirring 20～30min, to Reaction system drips 50～60mL bromine liquid, and controls to drip off in 30min, drip the backflow of complete laggard row Reacting 5～6 hours, reaction is filtered after terminating, and obtains filtering residue, first by filtering residue distilled water flushing 1～3 times, Add after washing in separatory funnel, remove aqueous phase, obtain organic facies, afterwards by organic facies at 60～70 DEG C Distill, and collect, the liquid collected carries out being evaporated to the 20～30% of original volume, Obtain obtaining the 2,4-bis-bromo-toluene of chloro-5-.

Specific embodiments

First weighing the 2 of 50～70g, 4-chlorophenesic acid is in 1000mL there-necked flask, then adds in bottle The phosphorus oxychloride of 25～40g, puts into there-necked flask in water-bath, and liter high-temperature, to 65～75 DEG C, is maintained at this At a temperature of stir, stir 50～60min, carry out esterification, after reaction terminates, add in bottle 150～ The carbon tetrachloride of 200mL, the formaldehyde of 80～120mL, and rise high-temperature to 80～90 DEG C be stirred hydrolysis Reaction, after stirring 1～2h, adds the dehydrated alcohol of gross mass 60% by the mixed liquor in bottle, continue 80～ Refluxing at 90 DEG C, after backflow 2～3h, the solution in bottle is carried out rotary evaporation, the solid obtained is 2,4-bis-chloro-5-nitrophenol；Taking 15～20g2, chloro-5 nitrophenols of 4-bis-are in equipped with agitator and thermometer In the there-necked flask of 500mL, flask is put in water-bath, and rises high-temperature to 60～80 DEG C, backward bottle The toluene of middle addition 150～170mL, is stirred 40～50min with magnetic stirring apparatus, stirring terminate after again Be warming up to 60～70 DEG C, in bottle add 25～30g calcium carbonate powder, and proceed stirring reaction 2～ 3h obtains 2, chloro-5 Methylnitrobenzenes of 4-bis-；After reaction terminates, in bottle, add the Polyethylene Glycol of 5～7g, and will Bath temperature is warming up to boiling, and is stirred with the rotating speed of 500～600r/min with magnetic stirring apparatus, stirring After 20～30min, in reaction system, drip 50～60mL bromine liquid, and control to drip off in 30min, drip Adding complete laggard row back flow reaction 5～6 hours, reaction is filtered after terminating, and obtains filtering residue, first by filtering residue steaming Distilled water is rinsed 1～3 time, adds in separatory funnel, remove aqueous phase, obtain organic facies, will have afterwards after washing Machine distills at 60～70 DEG C, and collects, and carries out being evaporated to original body by the liquid collected Long-pending 20～30%, i.e. can obtain 2, the bromo-toluene of the chloro-5-of 4-bis-.

Example 1

First weighing the 2 of 50g, 4-chlorophenesic acid is in 1000mL there-necked flask, then adds the trichlorine oxygen of 25g in bottle Phosphorus, puts into there-necked flask in water-bath, and liter high-temperature, to 65 DEG C, keeps stirring at this temperature, stirs 50min, Carry out esterification, after reaction terminates, in bottle, add the carbon tetrachloride of 150mL, the formaldehyde of 80mL, and Rise high-temperature and be stirred hydrolysis to 80 DEG C, after stirring 1h, the mixed liquor in bottle is added gross mass 60% Dehydrated alcohol, continue reflux at 80 DEG C, backflow 2h after, the solution in bottle is carried out rotary evaporation, The solid obtained is 2,4-bis-chloro-5-nitrophenol；Take chloro-5 nitrophenols of 15g2,4-bis-in equipped with stirring In the there-necked flask of the 500mL of device and thermometer, flask is put in water-bath, and rises high-temperature to 60 DEG C, Backward bottle in add the toluene of 150mL, be stirred 40min with magnetic stirring apparatus, stirring terminate after again It is warming up to 60 DEG C, in bottle, adds the calcium carbonate powder of 25g, and proceed stirring reaction 2h and obtain 2,4- Two chloro-5 Methylnitrobenzenes；After reaction terminates, in bottle, add the Polyethylene Glycol of 5g, and bath temperature is heated up To boiling, and it is stirred with the rotating speed of 500r/min with magnetic stirring apparatus, after stirring 20min, to reaction System drips 50mL bromine liquid, and controls to drip off in 30min, drip complete laggard row back flow reaction 5 little Time, reaction is filtered after terminating, is obtained filtering residue, first by filtering residue distilled water flushing 1 time, adds separatory after washing In funnel, remove aqueous phase, obtain organic facies, afterwards organic facies is distilled at 60 DEG C, and collect, The liquid collected carries out being evaporated to the 20% of original volume, i.e. can obtain 2, the bromo-first of the chloro-5-of 4-bis- Benzene.

Example 2

First weighing the 2 of 60g, 4-chlorophenesic acid is in 1000mL there-necked flask, then adds the trichlorine oxygen of 35g in bottle Phosphorus, puts into there-necked flask in water-bath, and liter high-temperature, to 70 DEG C, keeps stirring at this temperature, stirs 55min, Carry out esterification, after reaction terminates, in bottle, add the carbon tetrachloride of 175mL, the formaldehyde of 100mL, And rise high-temperature and be stirred hydrolysis to 85 DEG C, after stirring 1.5h, the mixed liquor in bottle is added total matter The dehydrated alcohol of amount 60%, continues to reflux at 85 DEG C, after backflow 2.5h, is carried out by the solution in bottle Rotary evaporation, the solid obtained is 2,4-bis-chloro-5-nitrophenol；Take chloro-5 nitrophenols of 17g2,4-bis- In the there-necked flask of the 500mL equipped with agitator and thermometer, flask is put in water-bath, and rise high temperature Degree to 70 DEG C, backward bottle in add the toluene of 160mL, be stirred 45min with magnetic stirring apparatus, stir It is warming up to 65 DEG C after mixing end again, in bottle, adds the calcium carbonate powder of 27g, and proceed stirring reaction 2.5h obtains 2, chloro-5 Methylnitrobenzenes of 4-bis-；After reaction terminates, in bottle, add the Polyethylene Glycol of 6g, and will Bath temperature is warming up to boiling, and is stirred with the rotating speed of 550r/min with magnetic stirring apparatus, stirs 25min After, in reaction system, drip 55mL bromine liquid, and control to drip off in 30min, drip complete laggard row and return Stream reaction 5.5 hours, reaction is filtered after terminating, is obtained filtering residue, first by filtering residue distilled water flushing 2 times, washes Add after washing in separatory funnel, remove aqueous phase, obtain organic facies, afterwards organic facies is steamed at 65 DEG C Evaporate, and collect, the liquid collected carries out being evaporated to the 25% of original volume, i.e. can obtain 2,4- The two bromo-toluene of chloro-5-.

Example 3

First weighing the 2 of 70g, 4-chlorophenesic acid is in 1000mL there-necked flask, then adds the trichlorine oxygen of 40g in bottle Phosphorus, puts into there-necked flask in water-bath, and liter high-temperature, to 75 DEG C, keeps stirring at this temperature, stirs 60min, Carry out esterification, after reaction terminates, in bottle, add the carbon tetrachloride of 200mL, the formaldehyde of 120mL, And rise high-temperature and be stirred hydrolysis to 90 DEG C, after stirring 2h, the mixed liquor in bottle is added gross mass The dehydrated alcohol of 60%, continues to reflux at 90 DEG C, after backflow 3h, is rotated by the solution in bottle Evaporation, the solid obtained is 2,4-bis-chloro-5-nitrophenol；Take chloro-5 nitrophenols of 20g2,4-bis-in dress Have in the there-necked flask of 500mL of agitator and thermometer, flask is put in water-bath, and rise high-temperature extremely 80 DEG C, backward bottle in add the toluene of 170mL, be stirred 50min, stirring knot with magnetic stirring apparatus Shu Houzai is warming up to 70 DEG C, adds the calcium carbonate powder of 30g in bottle, and proceeds stirring reaction 3h and obtain 2,4-bis-chloro-5 Methylnitrobenzenes；After reaction terminates, in bottle, add the Polyethylene Glycol of 7g, and by bath temperature It is warming up to boiling, and is stirred with the rotating speed of 600r/min with magnetic stirring apparatus, after stirring 30min, to Reaction system drips 60mL bromine liquid, and controls to drip off in 30min, drip complete laggard row back flow reaction 6 hours, reaction was filtered after terminating, and obtains filtering residue, first by filtering residue distilled water flushing 3 times, added after washing In separatory funnel, remove aqueous phase, obtain organic facies, afterwards organic facies is distilled at 70 DEG C, and receive Collection, the liquid collected carries out being evaporated to the 30% of original volume, i.e. can obtain 2, the chloro-5-of 4-bis- Bromo-toluene.

Claims (1)

1. one kind 2, the synthetic method of the bromo-toluene of the chloro-5-of 4-bis-, it is characterised in that the synthesis of 2, the 4-bis-bromo-toluene of chloro-5-:

(1) first weigh the 2 of 50～70g, 4-chlorophenesic acid in 1000mL there-necked flask, then in bottle add 25～ The phosphorus oxychloride of 40g, puts into there-necked flask in water-bath, and liter high-temperature, to 65～75 DEG C, is maintained at this temperature Lower stirring, stirs 50～60min, carries out esterification, after reaction terminates, adds 150～200mL in bottle Carbon tetrachloride, the formaldehyde of 80～120mL, and rise high-temperature and be stirred hydrolysis to 80～90 DEG C, After stirring 1～2h, the mixed liquor in bottle is added the dehydrated alcohol of gross mass 60%, continue at 80～90 DEG C Under reflux, backflow 2～3h after, the solution in bottle is carried out rotary evaporation, the solid obtained is 2,4- Two chloro-5-nitrophenols；

(2) taking 15～20g2, chloro-5 nitrophenols of 4-bis-are in three mouthfuls of burnings of the 500mL equipped with agitator and thermometer In Ping, flask is put in water-bath, and rises high-temperature to 60～80 DEG C, backward bottle in add 150～170mL Toluene, be stirred 40～50min with magnetic stirring apparatus, stirring is warming up to 60～70 DEG C after terminating again, to Add the calcium carbonate powder of 25～30g in Ping, and proceed stirring reaction and 2～3h obtain 2, chloro-5 nitre of 4-bis- Base toluene；

(3), after above-mentioned reaction terminates, in bottle, add the Polyethylene Glycol of 5～7g, and bath temperature is warming up to boiling Rise, and be stirred with the rotating speed of 500～600r/min with magnetic stirring apparatus, after stirring 20～30min, to Reaction system drips 50～60mL bromine liquid, and controls to drip off in 30min, drip the backflow of complete laggard row Reacting 5～6 hours, reaction is filtered after terminating, and obtains filtering residue, first by filtering residue distilled water flushing 1～3 times, Add after washing in separatory funnel, remove aqueous phase, obtain organic facies, afterwards by organic facies at 60～70 DEG C Distill, and collect, the liquid collected carries out being evaporated to the 20～30% of original volume, Obtain obtaining the 2,4-bis-bromo-toluene of chloro-5-.