CN1228336C - Prepn of 4-chlorophthalic anhydride - Google Patents
Prepn of 4-chlorophthalic anhydride Download PDFInfo
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- CN1228336C CN1228336C CN 03151179 CN03151179A CN1228336C CN 1228336 C CN1228336 C CN 1228336C CN 03151179 CN03151179 CN 03151179 CN 03151179 A CN03151179 A CN 03151179A CN 1228336 C CN1228336 C CN 1228336C
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- benzoic anhydride
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Abstract
The present invention relates to a method for preparing 4-chlorophthalic anhydride, which takes phthalic acid mono-sodium salts as raw materials, takes water as mediums, takes a weak alkali solution as pH value regulating agents in a reaction system, and directly carries out a chlorination reaction by using chlorine gas. The weight ratio of the chlorine gas to benzoic anhydride is from 0.3 to 0.45, reaction temperature is from 50 to 70 DEG C, and reaction time is from two to five hours. The weak alkali solution is used as the pH value regulating agents in the reaction system, which is favorable to the stability of the pH value of the reaction system to obtain 4-chloro-o-benzene phthalic acid mono-sodium coarse salts having a high yield coefficient. The coarse salts are processed with desalting and dehydration in a closed ring to obtain coarse products of the 4-chlorophthalic anhydride, and are purified by a rectification method to obtain high purity 4-chlorophthalic anhydride.
Description
Technical field
The present invention relates to a kind of preparation method of 4-chloro-benzoic anhydride, belong to technical field of organic synthesis.
Background technology
The 4-chloro-benzoic anhydride is a kind of of many uses, fine chemical product that added value is high, can be used to prepare the monomer of polyimide such as biphenyl ether dianhydride, biphenyl dianhydride, becomes polyimide by monomer polymerization then, is mainly used in fields such as Aeronautics and Astronautics, microelectronics.
The preparation method that industrial value is arranged at present mainly is the clorox chlorination process of phthalic anhydride
(SU1004328, spy open clear 55-20705) and a chloro-o-xylene catalytic oxidation
(CN1324793A、CN1257867A、DE2236875)。Yet above two kinds of methods remain in many defectives.The hypochlorite oxidation method of phthalic anhydride adopts clorox to make chlorizating agent, and clorox exists with aqueous solution form, poor heat stability is difficult for prolonged storage, easily is decomposed into hydrochloric acid and oxygen in the slant acidity reaction system, its utilization ratio is low, and the yield of purpose product is not high enough in addition.One chloro-o-xylene catalytic oxidation, with the o-Xylol is starting raw material, obtain a chloro-o-xylene through chlorination reaction, rectifying separation, obtain 4-chloro-benzoic anhydride and 3-chloro-benzoic anhydride through high-temperature catalytic reaction, water absorption, dimethylbenzene azeotropic dehydration, rectifying separation then.But this method technical process is long, the cost height, and 4-chloro-benzoic anhydride/3-chloro-benzoic anhydride is than low (5.5/4.5), and 4-chloro-benzoic anhydride total recovery is lower.
Summary of the invention
The object of the present invention is to provide a kind of preparation method of 4-chloro-benzoic anhydride, this method has that technical process is short, reaction conditions is gentle, cost is low, yield is high, 4-chloro-benzoic anhydride/3-chloro-benzoic anhydride is than high, low cost and other advantages.
Technical scheme of the present invention is characterised in that, is raw material with adjacent benzene two machine formic acid list sodium salts, is medium with water, with the chlorine direct chlorination, with NaHCO
3The aqueous solution is as the pH value conditioning agent of reaction system, and the pH value of conditioned reaction system is 4~6, obtains 4-chlorophthalic acid list sodium crude salt, through desalination, dehydration closed-loop, obtains the thick product of 4-chloro-benzoic anhydride, obtains high-purity 4-chloro-benzoic anhydride by rectification under vacuum.
The concrete operations step of described technical scheme is as follows:
The first step prepares phthalic acid list sodium salt reaction solution
In five mouthfuls of flasks that have thermometer, chlorine ingress pipe, the reflux condensing tube that has the chlorine delivery line, pH meter, isobaric dropping funnel, magnetic stirring apparatus, add the phthalic acid list sodium salt of 1 part of weight and the water of 3~4 parts of weight, be heated to 75~95 ℃ then, dissolve fully until phthalic acid list sodium salt, get phthalic acid list sodium salt reaction solution, this reaction solution is cooled to 50~70 ℃;
The reaction of second one-step chlorination
Chlorine feeds the reaction solution bottom that obtains through the first step, byproduct of reaction-hydrogenchloride NaHCO through surge flask
3Aqueous solution neutralization, keeping pH value is 4~6, and control reaction temperature is at 50~70 ℃, and the reaction times is 2~5h, and white crystals is separated out gradually, and the chlorine consumption is 0.30~0.45 part of weight;
The 3rd step acidifying
After the reaction of second step finishes, add concentrated hydrochloric acid or vitriol oil acidifying 2h, reaction mixture becomes homogeneous phase solution, and the consumption of the concentrated hydrochloric acid or the vitriol oil is 0.60~0.70 part of weight;
The extraction of the 4th step
The homogeneous phase solution that the 3rd step was made is cooled to 25~35 ℃, and with the ether material extraction, the consumption of ether material is 4~5 parts of weight, and extraction phase washes with water;
The 5th step made thick product
After the extraction phase that the 4th step made takes off ether, add the refluxing xylene dehydration, the consumption of dimethylbenzene is 3~4 parts of weight, after the dehydration, takes off dimethylbenzene again, promptly gets the thick product of 4-chloro-benzoic anhydride;
The 6th step made smart product
The 5th thick product of 4-chloro-benzoic anhydride that make of step is through rectification under vacuum, can get purity and be 98% the smart product of 4-chloro-benzoic anhydride, phthalic acid list sodium salt relatively, and its yield is 50~60%wt.
With the background technology ratio, the present invention has following tangible advantage: technical process is short, reaction conditions is gentle, cost is low, yield is high.
Embodiment
For with better explanation the present invention, below be embodiments of the invention.All embodiment are by above-mentioned 4-chloro-benzoic anhydride preparation method's concrete operations step operation.
Embodiment 1
The first step prepares phthalic acid list sodium salt reaction solution
Add 49g phthalic acid list sodium salt and 170g water, be heated to 80 ℃ then,, be cooled to 60 ℃ then, get reaction solution to dissolving;
The reaction of second one-step chlorination
Chlorine feeds the reaction solution bottom with the speed of 0.127g/min, and control reaction temperature is at 60 ℃, and reaction 3h in reaction process, drips the 30%NaHCO3 aqueous solution, makes the pH value of reaction system maintain 4~6;
The 3rd step acidifying
Add the 33g concentrated hydrochloric acid, acidifying 2h, reaction mixture becomes homogeneous phase solution;
The extraction of the 4th step
Be cooled to 30 ℃, with 196~245g extracted with diethyl ether;
The 5th step made thick product
Add the dehydration of 147~196g refluxing xylene, after the dehydration, take off dimethylbenzene again, promptly obtain the thick product of 45g 4-chloro-benzoic anhydride, through gas chromatographic analysis, the thick group of products of 4-chloro-benzoic anhydride becomes phthalic anhydride 9.4%, 4-chloro-benzoic anhydride 61.3%, 3-chloro-benzoic anhydride 7.5%, promptly 4-chloro-benzoic anhydride/3-chloro-benzoic anhydride is than being (61.3/7.5), dichloro-phthalic anhydride 21.8%;
The 6th step made smart product
Get 26g 4-chloro-benzoic anhydride, purity 98%, yield 52%wt.
Embodiment 2
The first step prepares phthalic acid list sodium salt reaction solution
Add 49g phthalic acid list sodium salt and 170g water, be heated to 90 ℃ then,, be cooled to 70 ℃ then, get reaction solution to dissolving;
The reaction of second one-step chlorination
Chlorine feeds the reaction solution bottom with the speed of 0.127g/min, and control reaction temperature is at 70 ℃, and reaction 1h in reaction process, drips 30%NaHCO
3The aqueous solution, in and byproduct hydrogen chloride, make the pH value of reaction system constant substantially, changing chlorine speed then is 0.082g/min, temperature of reaction is 50 ℃, the reaction 3h;
The 3rd step acidifying
Add the 30g concentrated hydrochloric acid, acidifying 2h, reaction mixture becomes homogeneous phase solution;
The extraction of the 4th step
Be cooled to room temperature, with 196~245g extracted with diethyl ether;
The 5th step made thick product
Add the dehydration of 147~196g refluxing xylene, after the dehydration fully, take off dimethylbenzene again, promptly obtain the thick product of 46g 4-chloro-benzoic anhydride, through gas chromatographic analysis, the thick group of products of 4-chloro-benzoic anhydride becomes phthalic anhydride 10.7%, 4-chloro-benzoic anhydride 65.3%, 3-chloro-benzoic anhydride 5.5%, dichloro-phthalic anhydride 20.1%;
The 6th step made smart product
Get 28g 4-chloro-benzoic anhydride, purity 98%, yield 57.1%wt.
Claims (3)
1. the preparation method of a 4-chloro-benzoic anhydride, it is characterized in that, with phthalic acid list sodium salt is raw material, with water is medium, directly carry out chlorination reaction with chlorine, with the pH value conditioning agent of weak caustic solution as reaction system, the pH value of conditioned reaction system is 4~6, obtain 4-chlorophthalic acid list sodium crude salt, obtain the thick product of 4-chloro-benzoic anhydride through desalination, dehydration closed-loop again, and purify by rectificating method, obtain high-purity 4-chloro-benzoic anhydride, the weight ratio of chlorine and phthalic anhydride is 0.3~0.45, and temperature of reaction is 50~70 ℃, and the reaction times is 2~5h.
2. method according to claim 1 is characterized in that, weak caustic solution is NaHCO
3The aqueous solution.
3. method according to claim 1 and 2 is characterized in that, the concrete operations step is as follows:
The first step prepares phthalic acid list sodium salt reaction solution
In five mouthfuls of flasks that have thermometer, chlorine ingress pipe, the reflux condensing tube that has the chlorine delivery line, pH meter, isobaric dropping funnel, magnetic stirring apparatus, add the phthalic acid list sodium salt of 1 part of weight and the water of 3~4 parts of weight, be heated to 75~95 ℃ then, dissolve fully until phthalic acid list sodium salt, get phthalic acid list sodium salt reaction solution, this reaction solution is cooled to 50~70 ℃;
The reaction of second one-step chlorination
Chlorine feeds the reaction solution bottom that obtains through the first step, byproduct of reaction-hydrogenchloride NaHCO through surge flask
3Aqueous solution neutralization, keeping pH value is 4~6, and control reaction temperature is at 50~70 ℃, and the reaction times is 2~5h, and white crystals is separated out gradually, and the chlorine consumption is 0.30~0.45 part of weight;
The 3rd step acidifying
After the reaction of second step finishes, add concentrated hydrochloric acid or vitriol oil acidifying 2h, reaction mixture becomes homogeneous phase solution, and the consumption of the concentrated hydrochloric acid or the vitriol oil is 0.60~0.70 part of weight;
The extraction of the 4th step
The homogeneous phase solution that the 3rd step was made is chilled to 25~35 ℃, and with the ether material extraction, the consumption of ether material is 4~5 parts of weight, and extraction phase washes with water;
The 5th step made thick product
After the extraction phase that the 4th step made takes off ether, add the refluxing xylene dehydration, the consumption of dimethylbenzene is 3~4 parts of weight, after the dehydration, takes off dimethylbenzene again, has both got the thick product of 4-chloro-benzoic anhydride;
The 6th step made smart product
The 5th thick product of 4-chloro-benzoic anhydride that make of step is through rectification under vacuum, can get purity and be 98% the smart product of 4-chloro-benzoic anhydride, phthalic acid list sodium salt relatively, and its yield is 50~60%wt.
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CN 03151179 CN1228336C (en) | 2003-09-25 | 2003-09-25 | Prepn of 4-chlorophthalic anhydride |
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Families Citing this family (5)
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AR103071A1 (en) * | 2014-12-30 | 2017-04-12 | Dow Global Technologies Llc | PROCESS TO PRODUCE 4-AZIDOSULPHONYLPHALL ANHYDRIDE |
CN105541677A (en) * | 2016-02-17 | 2016-05-04 | 威海翔宇环保科技股份有限公司 | Preparation of novel bactericide bissulfone |
CN109438219A (en) * | 2018-11-14 | 2019-03-08 | 淮阴工学院 | A method of preparing single chlorophthalic acid in the continuous flow reactor of microchannel |
CN112961132A (en) * | 2021-02-24 | 2021-06-15 | 沧州临港丰亚化工有限公司 | Method for preparing monochlorophthalic anhydride in micro-channel continuous flow reactor |
CN114853705A (en) * | 2022-04-24 | 2022-08-05 | 河北海力香料股份有限公司 | Method for preparing chlorophthalic anhydride by recovering 4-chlorophthalic acid monosodium salt reaction mother liquor |
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