CN105801380A - Method for separating 2,5-dichlorophenol and 2,4-dichlorophenol - Google Patents
Method for separating 2,5-dichlorophenol and 2,4-dichlorophenol Download PDFInfo
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
- C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
- C07C37/88—Use of additives, e.g. for stabilisation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
- C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
- C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
- C07C37/84—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by crystallisation
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Abstract
The invention discloses a method for separating 2,5-dichlorophenol and 2,4-dichlorophenol, belonging to the technical field of fine chemical industry. According to the method, the 2,5-dichlorophenol is separated out by a urea addition process, and then the less 2,5-dichlorophenol is separated from the 2,4-dichlorophenol by steps of ammonia water dissolution, crystallization and the like, so that the 2,5-dichlorophenol is thoroughly separated from the 2,4-dichlorophenol. Compared with the prior art, the method has the advantages of being low in cost, simple in operation technology and less in energy consumption.
Description
Technical field
The present invention relates to a kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, belong to technical field of fine.
Background technology
Chlorophenesic acid is the organic intermediate that a class is important, and in the compound of numerous chlorophenesic acids, 2,5-chlorophenesic acids and 2, the effect of 4-chlorophenesic acid is the most prominent.2,5-chlorophenesic acids are the key intermediates of herbicide dicamba, are also nitrogen fertilizer potentiating agent and leather fungicide simultaneously.2,4-chlorophenesic acids are a kind of important fine chemical products, are mainly used in pesticide, medicine, Additives Products.
The chlorophenesic acid produced by the hydrolysis of 1,2,4-trichloro-benzenes has 2,5-chlorophenesic acid and 2,4 dichloro phenol and 3,4-chlorophenesic acid these three isomer.3,4-chlorophenesic acids are due to its boiling point ratio 2,5-chlorophenesic acid and 2, and 4-chlorophenesic acid is high about 40 DEG C, can be separated by rectification, and 2,5-chlorophenesic acids and 2,4-chlorophenesic acid is difficult to be separated by rectification very close to (only differing from 1 DEG C) due to boiling point.
The patent of invention of Publication No. CN101412664, disclose a kind of 2,4-chlorophenesic acid and 2, the separation method of 5-dichlorophenol mixture, the method is to state ultimate principle based on Supramolecular Assembling, utilizes and topological between host molecule and guest molecule matches, separates 2 with the method for molecular recognition, 4/2,5-mixed dichlorobenzene phenol.Due to 2,4-chlorophenesic acid and 2,5-chlorophenesic acid is different at spatial configuration of molecules, polarity exists certain difference, thus there is identification abilitys different between distinctive host molecule, and different from the intermolecular interaction difficulty or ease of morpholine or other heterocyclic compounds, by Molecular Recognization, thus reach the purpose separated.Although the method can realize the separation of two kinds of chlorophenesic acids, but its technical process is tediously long, reacts wayward, and separation costs is high, is unfavorable for realizing industrialization.
And for example, the United States Patent (USP) of Publication No. US 3463498, which disclosing employing carbamide and 2,5-chlorophenesic acid addition obtains 2,5-chlorophenesic acid urea adduct, utilize urea adduct and 2, the principle that 4-chlorophenesic acid degree of crystallinity at the same temperature is different, then by crystallization, addition product is separated, 2 are obtained, 5-chlorophenesic acid by hydrolysis.Although the method isolated purer 2,5-chlorophenesic acid, but containing 2 in filtrate, still containing a small amount of 2 while 4-chlorophenesic acid, 5-chlorophenesic acid, it is impossible to realize 2,4-chlorophenesic acid and 2, the purpose that 5-chlorophenesic acid is kept completely separate.
Summary of the invention
Present invention seek to address that can not be by 2 in prior art, 4-chlorophenesic acid and 2, 5-chlorophenesic acid is kept completely separate and separation costs is high, the problem of complex process, a kind of new separation 2 is proposed, 5-chlorophenesic acid and 2, the method of 4-chlorophenesic acid, by carbamide addition process by 2, after 5-chlorophenesic acid is separated, pass through ammonia solvent again, the steps such as crystallization purify repeatedly, by a small amount of 2, 5-chlorophenesic acid and 2, 4-chlorophenesic acid separates, thus realize 2, 5-chlorophenesic acid and 2, being completely separated of 4-chlorophenesic acid, there is processing cost low, operating procedure is simple, the advantage of less energy consumption.
In order to realize foregoing invention purpose, technical scheme is as follows:
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 90～120 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 60～90 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；It should be noted that the air-distillation that the method sloughing solvent in this step is routine or decompression are distilled, the most no longer describe in detail.
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.5～1.5 times amount, it is warming up to 40～80 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 40～80 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the sterling separation rate of 2,5-chlorophenesic acids reaches more than 95%, the sterling separation rate of 2,4-chlorophenesic acids reaches more than 85%；The definition of sterling separation rate is: the quality of sterling A obtained after separation with separate the ratio of the initial mass of A in front mixture；It should be noted that the method for dehydration is conventional air-distillation in this step, the most no longer describe in detail.
In described step A, the molal quantity of the carbamide of addition is 2,0.5～2 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 90～120 DEG C, the time of reaction is 0.5～2h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1～3 times of the mixture weight of 4-chlorophenesic acid.
In step A, described add water in filter cake the water yield is mixture weight 1～3 times.
In step A, described addition water in filter cake, it is warming up to 60～90 DEG C, the time continuing reaction is 0.5～2h.
In step B, the ammonia of described addition mixture total mole number 0.5～1.5 times amount, it is warming up to 40～80 DEG C, the time continuing reaction is 1～3h.
In step B, described add water in mixture amount is mixture weight 1～3 times；Amount is filter cake weight 1～3 times of water is added in filter cake.
In step A, after described aqueous phase is concentrated, obtains carbamide, recyclable recycling, improve raw material availability, reduce production cost.
Beneficial effects of the present invention:
(1) present invention isolates most 2 by carbamide addition process, 5-chlorophenesic acid, then by ammonia solvent, crystallize, separate, by most 2,4-chlorophenesic acid is separated, and finally repeats carbamide and ammonia treatment step, by 2,5-chlorophenesic acid, 2,4-chlorophenesic acid is completely isolated, after testing, 2, the separation rate of 5-chlorophenesic acid has reached more than 95%, and the separation rate of 2,4-chlorophenesic acids has reached more than 85%；Compared with method of the prior art, the processing cost of the present invention is low, operating procedure simple, less energy consumption, is suitable for industrialized production.
(2) in step A of the present invention, the molal quantity adding carbamide is 2, and 0.5～2 times of 5-chlorophenesic acid molal quantity can make 2, and 5-chlorophenesic acid fully reacts with carbamide, improves 2, the sterling separation rate of 5-chlorophenesic acid.
(3) in step A of the present invention, described 2,5-chlorophenesic acid and 2, after the mixture of 4-chlorophenesic acid adds carbamide, at 90～120 DEG C, the time of insulation reaction is 0.5～2h, and reaction can promote 2 under this condition, and 5-chlorophenesic acid reacts with carbamide, ensureing 2,5-chlorophenesic acid urea adduct does not separates out simultaneously.
(4), in step A of the present invention, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1～3 times of the mixture weight of 4-chlorophenesic acid, to accelerate 2,5-chlorophenesic acid urea adduct separates out and fully dissolves and the 2 of carbamide additive reaction does not occurs, 4-chlorophenesic acid, reaches to separate purpose.
(5) in step A of the present invention, described add water in filter cake the water yield is mixture weight 1～3 times, make 2,5-chlorophenesic acid urea adduct can be rapidly hydrolyzed into 2, and 5-chlorophenesic acid and carbamide make 2 simultaneously, and 5-chlorophenesic acid does not solidifies and reduces wastewater flow rate.
(6) in step B of the present invention, the ammonia of described addition mixture total mole number 0.5～1.5 times amount, it is warming up to 40～80 DEG C, the time of insulation reaction is 1～3h, has both made 2,5-chlorophenesic acid and 2,4-chlorophenesic acid can fully react with ammonia, does not the most strengthen ammonia volume, it is to avoid cost increases.
(7) in step B of the present invention, described add water in mixture amount is mixture weight 1～3 times；Amount is filter cake weight 1～3 times of water is added, it is ensured that reactant concentration is suitable, does not increase the amount of technique waste water in filter cake；2,4 dichloro phenol in filter cake is played recrystallization purification effect simultaneously.
Detailed description of the invention
Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited to this.
Embodiment 1
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 90 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 60 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.5 times amount, it is warming up to 40 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 40 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 98%, the separation rate of 2,4-chlorophenesic acids reaches 90%.
Embodiment 2
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 120 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 90 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 1.5 times amount, it is warming up to 80 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 80 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 97%, the separation rate of 2,4-chlorophenesic acids reaches 88%.
In the present embodiment step A, the molal quantity adding carbamide is 2,0.5 times of 5-chlorophenesic acid molal quantity.
Embodiment 3
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 100 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 80 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 1 times amount, it is warming up to 60 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 60 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 95%, the separation rate of 2,4-chlorophenesic acids reaches 87%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,2 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 100 DEG C, the time of reaction is 0.5h.
Embodiment 4
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 110 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 70 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 1.2 times amount, it is warming up to 50 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 50 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 96%, the separation rate of 2,4-chlorophenesic acids reaches 89%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,1.2 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 110 DEG C, the time of reaction is 2h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1 times of the mixture weight of 4-chlorophenesic acid.
Embodiment 5
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 95 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 90 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.8 times amount, it is warming up to 70 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 70 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 94%, the separation rate of 2,4-chlorophenesic acids reaches 85%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,1.8 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 95 DEG C, the time of reaction is 1.2h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,3 times of the mixture weight of 4-chlorophenesic acid.
In step A, described add water in filter cake the water yield is mixture weight 1 times.
In step A, described in be warming up to 90 DEG C, continue reaction time be 0.5h.
Embodiment 6
The present embodiment is with the difference of embodiment 5: in step A, described add water in filter cake the water yield is mixture weight 3 times.
In step A, described in be warming up to 90 DEG C, continue reaction time be 2h.
Embodiment 7
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 110 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 60 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.8 times amount, it is warming up to 70 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 70 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 97%, the separation rate of 2,4-chlorophenesic acids reaches 98%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,1.8 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 110 DEG C, the time of reaction is 2h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,2.5 times of the mixture weight of 4-chlorophenesic acid.
In step A, described add water in filter cake the water yield is mixture weight 2 times.
In step A, described in be warming up to 60 DEG C, continue reaction time be 2h.
In step B, described in be warming up to 70 DEG C, continue reaction time be 1h.
Embodiment 8
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 120 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 90 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.8 times amount, it is warming up to 40 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 70 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 96%, the separation rate of 2,4-chlorophenesic acids reaches 88%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,1.8 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 120 DEG C, the time of reaction is 1h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1 times of the mixture weight of 4-chlorophenesic acid.
In step A, described add water in filter cake the water yield is mixture weight 1.5 times.
In step A, described in be warming up to 90 DEG C, continue reaction time be 1.8h.
In step B, described in be warming up to 40 DEG C, continue reaction time be 3h.
In step B, described add water in mixture amount is mixture weight 1 times；Amount is filter cake weight 1 times of water is added in filter cake.
Embodiment 9
The present embodiment is with the difference of embodiment 7:
In step B, being warming up to 80 DEG C after adding ammonia, the time continuing reaction is 1h.
In step B, described add water in mixture amount is mixture weight 3 times；Amount is filter cake weight 3 times of water are added in filter cake.
The organic solvent of the present embodiment is toluene.
Embodiment 10
A kind of separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 100 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 75 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；By filtrate after distillation sloughs organic solvent through decompression, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.8 times amount, it is warming up to 60 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 70 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after normal pressure distillation dehydration, and then circulation step A and step B, until the separation rate of 2,5-chlorophenesic acids reaches 97%, the separation rate of 2,4-chlorophenesic acids reaches 90%.
In step A of the present embodiment, the molal quantity adding carbamide is 2,1 times of 5-chlorophenesic acid molal quantity.
In step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 100 DEG C, the time of reaction is 1h.
In step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1 times of the mixture weight of 4-chlorophenesic acid.
In step A, described add water in filter cake the water yield is mixture weight 2 times.
In step A, described in be warming up to 75 DEG C, continue reaction time be 2h.
In step B, described in be warming up to 60 DEG C, continue reaction time be 2h.
In step B, described add water in mixture amount is mixture weight 2 times；Amount is filter cake weight 2 times of water are added in filter cake.
In order to reduce production cost further, in step A, after described aqueous phase is concentrated, reclaim carbamide.
The organic solvent of the present embodiment is dimethylbenzene.
Embodiment 11
The present embodiment is as a example by separating 200g mixture, and the present invention will be further described in detail.
By 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture 200g(is wherein, 2,5-chlorophenesic acid content 80%, 2,4-chlorophenesic acid content 16%), it is heated to 110 DEG C, adds 60g carbamide, lower the temperature after insulation reaction 0.5h, when temperature is down to below 90 DEG C, add 300g dimethylbenzene, be slowly cooled to room temperature, sucking filtration.Adding 400g water to filter cake, be warming up to 80 DEG C of insulation reaction 0.5h, separatory, i.e. obtain 2,5-chlorophenesic acid 147.1g, after testing, purity is 98.1%, recyclable carbamide 58g after aqueous phase is concentrated, recycling；
Filtrate is reclaimed through precipitation and is obtained 2 after dimethylbenzene, 5-chlorophenesic acid and 2,4-dichlorophenol mixture about 55g, add 16g strong aqua ammonia and 110g water, be warming up to 45 DEG C of insulation reaction 2h, filter after being slowly dropped to room temperature, 25g water is added in filter cake, it is warming up to 60 DEG C, is then slowly dropped to room temperature, filter, i.e. obtain 2,4-chlorophenesic acid 26.5g, after testing, purity is 97.3%.
The above, be only presently preferred embodiments of the present invention, and the present invention not does any pro forma restriction, every above example is made according to the technical spirit of the present invention any simple modification, equivalent variations, within each falling within protection scope of the present invention.
Claims (9)
1. a separation 2,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: comprise the following steps:
A. carbamide addition
To 2,5-chlorophenesic acid and 2, the mixture of 4-chlorophenesic acid adds carbamide, at 90～120 DEG C after reaction, is cooled to less than 90 DEG C, is subsequently adding organic solvent, sucking filtration after cooling, obtain filtrate and filter cake；Adding water in filter cake, be warming up to 60～90 DEG C, continue reaction, then separatory, obtain organic facies and aqueous phase, organic facies is 2,5-chlorophenesic acid；After filtrate is sloughed organic solvent, obtain 2,5-chlorophenesic acid and 2,4-dichlorophenol mixture；
B. ammonia treatment
2 obtained to step A, 5-chlorophenesic acid and 2,4-dichlorophenol mixture adds water and the ammonia of mixture total mole number 0.5～1.5 times amount, it is warming up to 40～80 DEG C, continue reaction, carry out filtering for the first time after solution temperature is down to room temperature, in filter cake, then add water, it is warming up to 40～80 DEG C, then lower the temperature, carry out second time and filter, obtain filtrate and filter cake, described filter cake is 2,4-chlorophenesic acid；
The filtrate that described step B second time is filtrated to get is back to step A after dehydration, and then circulation step A and step B, until the sterling separation rate of 2,5-chlorophenesic acids reaches more than 95%, the sterling separation rate of 2,4-chlorophenesic acids reaches more than 85%.
2. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step A, the molal quantity adding carbamide is 2,0.5～2 times of 5-chlorophenesic acid molal quantity.
3. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterized in that: in step A, described 2,5-chlorophenesic acid and 2, after adding carbamide in the mixture of 4-chlorophenesic acid, at 90～120 DEG C, the time of reaction is 0.5～2h.
4. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step A, the addition of described organic solvent is 2,5-chlorophenesic acid and 2,1～3 times of the mixture weight of 4-chlorophenesic acid.
5. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step A, described add water in filter cake the water yield is mixture weight 1～3 times.
6. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step A, described addition water in filter cake, it is warming up to 60～90 DEG C, the time continuing reaction is 0.5～2h.
7. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step B, the ammonia of described addition mixture total mole number 0.5～1.5 times amount, it is warming up to 40～80 DEG C, the time continuing reaction is 1～3h.
8. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step B, described add water in mixture amount is mixture weight 1～3 times；Amount is filter cake weight 1～3 times of water is added in filter cake.
9. a kind of separation 2 as claimed in claim 1,5-chlorophenesic acid and 2, the method for 4-chlorophenesic acid, it is characterised in that: in step A, after described aqueous phase is concentrated, obtain carbamide.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109020787A (en) * | 2018-07-10 | 2018-12-18 | 青岛科技大学 | A kind of method of chlorophenol high-boiling components resource utilization |
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| US3462498A (en) * | 1965-09-10 | 1969-08-19 | Boehringer Sohn Ingelheim | Process for isolation of 2,5-dichlorophenol from an isomeric mixture of dichlorophenols |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109020787A (en) * | 2018-07-10 | 2018-12-18 | 青岛科技大学 | A kind of method of chlorophenol high-boiling components resource utilization |
| CN109020787B (en) * | 2018-07-10 | 2024-05-10 | 青岛科技大学 | Method for recycling chlorophenol high-boiling-point substances |
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