CN103232339A - Preparation method of chlorinated phenylacetic acid - Google Patents
Preparation method of chlorinated phenylacetic acid Download PDFInfo
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- CN103232339A CN103232339A CN2013101375170A CN201310137517A CN103232339A CN 103232339 A CN103232339 A CN 103232339A CN 2013101375170 A CN2013101375170 A CN 2013101375170A CN 201310137517 A CN201310137517 A CN 201310137517A CN 103232339 A CN103232339 A CN 103232339A
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- hydrochloric acid
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- acetic acid
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Abstract
The invention discloses a preparation method of chlorinated phenylacetic acid. The preparation method comprises the following steps of: (1) heating chlorinated benzyl cyanide to 50-120 DEG C, dropping hydrochloric acid into the chlorinated benzyl cyanide or dropping the molten chlorinated benzyl cyanide into the hydrochloric acid in a molar ratio of the hydrochloric acid to the chlorinated benzyl cyanide of (1.2-5):1, and after dropping, carrying out a thermal reaction for 1.5-5 hours; and (2) adding water into the reaction system of the step (1), stirring for mixing and dissolving, cooling for crystallization, carrying out extraction filtration, washing the obtained crystal with water, and drying to obtain a chlorinated phenylacetic acid product. According to the preparation method, a hydrochloric acid hydrolysis process is adopted, so that the defects of high consumption (acid and alkali consumption at the same time) and more byproducts (byproducts of ammonia or ammonium salt and sodium salt) are avoided, the environmental pollution is reduced, and compared with a sulphuric acid hydrolysis process, the hydrochloric acid hydrolysis process can not generate a coking phenomenon, is thorough in hydrolysis, does not generate intermediate products, is simple in after-treatment, and improves the yield and quality of a product.
Description
Technical field
The present invention relates to the synthesis technical field of chlorophenyl acetic acid, particularly a kind of chloro benzyl cyanide hydrolysis prepares the method for chlorophenyl acetic acid.
Background technology
The chloro benzyl cyanide hydrolysis is to prepare chlorophenyl acetic acid method commonly used, its processing condition are simple relatively, easy and the easy control of operation, be that present domestic research at most also is the most ripe industrialized preparing process, hydrolysis process is divided into two kinds: with highly basic such as sodium hydroxide or potassium hydroxide the chlorinated benzene acetonitrile is made chlorophenyl acetic acid sodium for first kind, decolouring back acidifying, crystallization get product; Second kind directly gets chlorophenyl acetic acid with acid hydrolysis, crystallization, and used acid is the mixture of sulfuric acid or sulfuric acid and acetic acid.Reaction equation is as follows:
1, basic hydrolysis
2, acid hydrolysis
Problem and shortcoming that above-mentioned two kinds of hydrolysis processs exist are:
1) alkali process hydrolysis had not only consumed alkali but also consumption acids, and Atom economy is poor, but also wants by-product ammonia and salt;
2) alkali process hydrolysis generates ammonia, takes organism out of when ammonia is overflowed, and contaminate environment adopts water to absorb or sour the absorption all can't directly be used because organism exceeds standard;
3) the chlorophenyl acetic acid sodium solution needs decolouring, produces solid uselessly, and decolorization discharges foul smell, and operating environment is poor;
4) adopt sulphuric acid hydrolysis, the liquid carbonization coking that can induce reaction under the pyroreaction, the aftertreatment difficulty also influences outward appearance and the quality of product, produces that to contain the organism spent acid in a large number difficult; For example publication number is among the preparation method of the disclosed chlorophenyl acetic acid of patent documentation of CN1927810A, need remove the by product organic impurity that sulfuric acid causes by vaporizing extract process;
5) though the sulfuric acid acetate mixture can partly be avoided the shortcoming of sulphuric acid hydrolysis, and it has not only consumed organic acid, and because having added organic acid can increase the solubleness of product in mother liquor, reduce the yield of product, increased the intractability of waste water simultaneously.
Summary of the invention
In view of this, the invention provides a kind of preparation method of chlorophenyl acetic acid, this method can avoid alkali process hydrolysis to consume shortcomings high, that by-product is many, avoid the easy carbonization coking of sulfuric acid process hydrolysis, aftertreatment complexity, difficult, the ropy shortcoming of product appearance of waste liquid simultaneously, have consumption less, advantage such as transformation efficiency height, aftertreatment are simple, the product appearance quality is good.
The preparation method of chlorophenyl acetic acid of the present invention may further comprise the steps:
1) the chlorinated benzene acetonitrile is heated to 50 ~ 120 ℃, dripping hydrochloric acid or the chlorinated benzene acetonitrile of molten state dropped in the hydrochloric acid in the chlorinated benzene acetonitrile then, the mol ratio of hydrochloric acid and chlorinated benzene acetonitrile is 1.2 ~ 5:1, dropwises the back insulation reaction 1.5 ~ 5 hours;
Its chemical equation is:
2) in the reaction system of step 1), add water, stir miscible, crystallisation by cooling then, suction filtration, the gained crystal washes with water, after the drying, obtain the chlorophenyl acetic acid product.
Further, the massfraction of described hydrochloric acid is 15% ~ 37%.
Further, described step 2) in, in the reaction system of step 1), add in the ammoniacal liquor and excessive hydrochloric acid earlier, in reaction system, add water again, stir miscible.
Further, described step 2) excessive hydrochloric acid in the reaction system in, first underpressure distillation recycling step 1) adds water again in reaction system, stir miscible.
Beneficial effect of the present invention is: the present invention adopts the technology of hydrochloric acid hydrolysis, the shortcoming of having avoided alkaline process to consume high (consuming bronsted lowry acids and bases bronsted lowry simultaneously), by-product many (ammonia gas as byproduct or ammonium salt and sodium salts), reduced environmental pollution, and hydrochloric acid hydrolysis technology is compared with sulphuric acid hydrolysis technology, can not produce the coking phenomenon, hydrolysis is thorough, and no intermediate product generates, aftertreatment is simple, has improved product yield and quality.
Embodiment
The preparation method of chlorophenyl acetic acid of the present invention may further comprise the steps:
1) the chlorinated benzene acetonitrile is heated to 50 ~ 120 ℃, dripping hydrochloric acid or the chlorinated benzene acetonitrile of molten state dropped in the hydrochloric acid in the chlorinated benzene acetonitrile then, the mol ratio of hydrochloric acid and chlorinated benzene acetonitrile is 1.2 ~ 5:1, dropwises the back insulation reaction 1.5 ~ 5 hours; The massfraction of described hydrochloric acid preferred 15% ~ 37%;
2) in the reaction system of step 1), add water, stir miscible, crystallisation by cooling then, suction filtration, the gained crystal washes with water, after the drying, obtain the chlorophenyl acetic acid product; Also can be earlier in the reaction system of step 1), add in the ammoniacal liquor and excessive hydrochloric acid, in reaction system, add water again, stir miscible, crystallisation by cooling then, suction filtration, the gained crystal washes with water, after the drying, obtain the chlorophenyl acetic acid product; All right first underpressure distillation recycling step 1) excessive hydrochloric acid in the reaction system adds water again in reaction system, stir miscible.
To be described in detail with the example that is prepared as of o-chlorobenzene acetic acid below.
The preparation of o-chlorobenzene acetic acid may further comprise the steps:
1) takes back the adjacent chlorobenzene acetonitrile 306g(2mol that adds content 99% in the four-hole boiling flask that flows prolong, thermometer, dropping funnel at 2000mL), adding massfraction in the dropping funnel is 30% hydrochloric acid 487g(4mol), the confined reaction system, be heated to 80 ℃, dripping hydrochloric acid dropwises the back 80 ℃ of insulation reaction 5 hours;
2) sampling, HPLC analyzes that o-chlorobenzene acetic acid content is 97.5% in the reaction system learn step 1), and adjacent chlorobenzene acetonitrile content is 0.23%; In reaction system, add 500mL water, stir misciblely, be cooled to 35 ℃ of crystallizations then, suction filtration, gained crystal with the washing of 300mL warm water, 30 ~ 40 ℃ of drying under reduced pressure after, obtain white o-chlorobenzene acetic acid product 329g, product purity is 99.4%, yield is 95.9%.
Explanation is at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although by invention has been described with reference to the preferred embodiments of the present invention, but those of ordinary skill in the art is to be understood that, can make various changes to it in the form and details, and not depart from the spirit and scope of the present invention that appended claims limits.
Claims (4)
1. the preparation method of a chlorophenyl acetic acid is characterized in that: may further comprise the steps:
1) the chlorinated benzene acetonitrile is heated to 50 ~ 120 ℃, dripping hydrochloric acid or the chlorinated benzene acetonitrile of molten state dropped in the hydrochloric acid in the chlorinated benzene acetonitrile then, the mol ratio of hydrochloric acid and chlorinated benzene acetonitrile is 1.2 ~ 5:1, dropwises the back insulation reaction 1.5 ~ 5 hours;
2) in the reaction system of step 1), add water, stir miscible, crystallisation by cooling then, suction filtration, the gained crystal washes with water, after the drying, obtain the chlorophenyl acetic acid product.
2. the preparation method of chlorophenyl acetic acid according to claim 1, it is characterized in that: the massfraction of described hydrochloric acid is 15% ~ 37%.
3. the preparation method of chlorophenyl acetic acid according to claim 1 and 2 is characterized in that: described step 2), add in the ammoniacal liquor and excessive hydrochloric acid in the reaction system of step 1) earlier, add water again in reaction system, stir miscible.
4. the preparation method of chlorophenyl acetic acid according to claim 1 and 2 is characterized in that: described step 2), first underpressure distillation recycling step 1) reaction system in excessive hydrochloric acid, in reaction system, add water again, stir miscible.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013101375170A CN103232339A (en) | 2013-04-19 | 2013-04-19 | Preparation method of chlorinated phenylacetic acid |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013101375170A CN103232339A (en) | 2013-04-19 | 2013-04-19 | Preparation method of chlorinated phenylacetic acid |
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| CN103232339A true CN103232339A (en) | 2013-08-07 |
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| CN2013101375170A Pending CN103232339A (en) | 2013-04-19 | 2013-04-19 | Preparation method of chlorinated phenylacetic acid |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1927810A (en) * | 2006-09-18 | 2007-03-14 | 武汉有机实业股份有限公司 | Preparation method of chlorophenyl acetic acid |
| CN102584565A (en) * | 2012-02-07 | 2012-07-18 | 沧州那瑞化学科技有限公司 | Preparation method for 2,4,5-trifluoro benzene acetic acid |
-
2013
- 2013-04-19 CN CN2013101375170A patent/CN103232339A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1927810A (en) * | 2006-09-18 | 2007-03-14 | 武汉有机实业股份有限公司 | Preparation method of chlorophenyl acetic acid |
| CN102584565A (en) * | 2012-02-07 | 2012-07-18 | 沧州那瑞化学科技有限公司 | Preparation method for 2,4,5-trifluoro benzene acetic acid |
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Application publication date: 20130807 |