CN102653509A

CN102653509A - Method for co-production of high-purity chloroacetic acid and acetylchloride by using acetic anhydride chlorination

Info

Publication number: CN102653509A
Application number: CN2011100501092A
Authority: CN
Inventors: 刘长飞; 张玉章
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-03
Filing date: 2011-03-03
Publication date: 2012-09-05

Abstract

The invention provides a method for synthesizing high-purity chloroacetic acid and high-purity acetylchloride by taking acetic anhydride and chlorine as materials and taking ferric trichloride or hydrogen chloride as a catalyst. The catalyst such as ferric trichloride or hydrogen chloride is added into the acetic anhydride in an amount accounting for 0.02 percent-0.5 percent of the weight of the acetic anhydride, and the acetic anhydride and the chloride react in a chlorination reactor to generate chloroacetic acid and acetylchloride. The generated acetylchloride is evaporated out of the reactor at a temperature of over 60 DEG C, and condensation and recovery are carried out to obtain an acetylchloride product with the purity of more than 99.5 percent. The chloroacetic acid is recrystallized to obtain a high-purity chloroacetic acid product with the purity of more than 99.6 percent.

Description

The method of a kind of high-purity Mono Chloro Acetic Acid of aceticanhydride chlorination coproduction and Acetyl Chloride 98Min.

Technical field:

The present invention relates to the technology of a kind of high-purity Mono Chloro Acetic Acid of aceticanhydride chlorination coproduction and Acetyl Chloride 98Min., belong to technical field of chemical synthesis.

Background technology:

The acetic acid catalysis chlorination is the topmost method of Mono Chloro Acetic Acid of producing both at home and abroad at present.It can be divided into two kinds of batch production technology and continuous production technologies again.Batch production technology is that general SULPHUR POWDER is a catalyzer; Control 3% (mass percent) that its consumption is about the acetate total amount; The two-stage tandem chlorination is adopted in reaction, main pot logical chlorine under 90 ℃, and control reaction temperature is 96-100 ℃; Secondary pot temperature of reaction is 85-90 ℃, when reaction end density is 1.35, is reaction end.Insulation reaction adds the circulating mother liquor crystallisation by cooling after 1 hour, add crystal seed at the above 1-2 of zero pour ℃, slowly cools to about 25 ℃, makes product through suction filtration or spinning.Tail gas hydrogenchloride send packed absorber to reclaim by-product hydrochloric acid.At present, abroad this method is eliminated, and the manufacturer of China mainly adopts this method to produce, though this method production technique is fairly simple; But consume height, yield poorly, products obtained therefrom is of poor quality, and the production cycle is long; Production cost is high, three-waste pollution is serious, and the catalyzer SULPHUR POWDER not only pollutes major product, also contaminating by-products hydrochloric acid; Sometimes also cause the obstruction of pipe-line equipment, make production undesired, make the range of application of product receive certain restriction.The continuous processing preparation process for chloroacetic acid is to be raw material with acetate, liquid chlorine, and aceticanhydride and sulfuric acid are catalyzer, make Mono Chloro Acetic Acid through processes such as acetate chlorination, distillation, crystallization, separation, dryings.This method products obtained therefrom quality is high, and raw material consumption is few, and raw material chlorine is required not too harshness, can use liquid chlorine tail gas or the production of gas chlorine, and weak point is that reaction conversion ratio is low, only has about 45%, has increased steam consumption and power consumption.At present this method is to produce chloroacetic main method in the world, and the large-scale production of chloroacetic acid enterprise of states such as the U.S., Japan, Germany, Holland, Canada all adopts this method to produce.

Chloroacetyl chloride is a kind of important organic intermediate, and especially application is the widest at aspects such as agricultural chemicals, medicine, and demand increases year by year.The traditional Mono Chloro Acetic Acid phosphorus trichloride chlorination of domestic main employing is at present produced, and this method is difficult to separate owing to be prone to contain phosphorus compound in the product, and seriously polluted, and equipment corrosion is serious, does not possess competitive power, and is on the verge of being replaced.Especially poor product quality, purity is generally between 90%-95%.The external at present main ketene chlorination route that adopts advanced easy mass-producing. but this method investment is bigger, and technical difficulty is bigger.

Summary of the invention:

The invention provides a kind of is raw material with aceticanhydride and chlorine, is catalyzer with iron trichloride or hydrogenchloride, the method for synthesis of high purity Mono Chloro Acetic Acid and high-purity acetyl chlorine.

Reaction principle:

(1) aceticanhydride and chlorine generate chlorination aceticanhydride and hydrogenchloride CH in 20 ℃-80 ℃ (adding catalyzer) reaction ₃-CO-O-CO-CH ₃+ Cl ₂→ ClCH ₂-CO-O-CH ₃+ HCl

(aceticanhydride) (chlorine) (chlorination aceticanhydride) (hydrogenchloride)

(2) chlorination aceticanhydride and hydrogenchloride further react and generate Acetyl Chloride 98Min. and Mono Chloro Acetic Acid ClCH ₂-CO-O-CH ₃+ HCl → ClCH ₂-CO-OH+CH ₃-CO-Cl

(chlorination aceticanhydride) (hydrogenchloride) (Mono Chloro Acetic Acid) (Acetyl Chloride 98Min.)

Technological process:

(1) catalyzer iron trichloride or hydrogenchloride add in the aceticanhydride in the ratio of the 0.02%-0.5% of aceticanhydride weight;

(2) acetic anhydride catalysis agent composition and chlorine are through being preheated to 20 ℃--be passed into chlorination reaction after 60 ℃

Device carries out chlorination reaction, aceticanhydride and chlorine according to etc. molar ratio add;

(3) aceticanhydride and chlorine generate Mono Chloro Acetic Acid and Acetyl Chloride 98Min. in chlorination reactor.The Acetyl Chloride 98Min. that generates evaporates reactor drum under the temperature more than 60 ℃, through condensing and recycling, obtaining purity is the Acetyl Chloride 98Min. product more than 99.5%;

(4) to obtain purity be the high-purity Mono Chloro Acetic Acid product more than 99.6% to Mono Chloro Acetic Acid through recrystallization.

Technical characterstic:

(1) the chlorination sepn process is carried out in a reactor drum continuously;

(2) low equipment investment;

(3) can obtain high-purity Mono Chloro Acetic Acid and highly purified Acetyl Chloride 98Min. product.

Claims

1. one kind is raw material with aceticanhydride and chlorine, is catalyzer with iron trichloride or hydrogenchloride, the method for synthesis of high purity Mono Chloro Acetic Acid and high-purity acetyl chlorine.It is characterized in that this method comprises following each step:

Step 1, catalyzer iron trichloride or hydrogenchloride add in the aceticanhydride in the ratio of the 0.02%-0.5% of aceticanhydride weight.

Step 2, acetic anhydride catalysis agent composition and chlorine are through being preheated to 20 ℃--being passed into chlorination reactor after 60 ℃ carries out chlorination reaction, aceticanhydride and chlorine according to etc. the molar ratio adding.

Step 3, aceticanhydride and chlorine generate Mono Chloro Acetic Acid and Acetyl Chloride 98Min. in chlorination reactor.The Acetyl Chloride 98Min. that generates evaporates reactor drum under the temperature more than 60 ℃, through condensing and recycling, get the Acetyl Chloride 98Min. product.

Step 4, Mono Chloro Acetic Acid obtain high-purity Mono Chloro Acetic Acid product through recrystallization.

2. the method for claim 1 is characterized in that catalyzer iron trichloride or hydrogenchloride add in the aceticanhydride in the ratio of the 0.02%-0.5% of aceticanhydride weight.

3. the method for claim 1 is characterized in that aceticanhydride and chlorine generate Mono Chloro Acetic Acid and Acetyl Chloride 98Min. in chlorination reactor, and the Acetyl Chloride 98Min. of generation evaporates reactor drum under the temperature more than 60 ℃, through condensing and recycling, gets the Acetyl Chloride 98Min. product.

4. the method for claim 1 is characterized in that Mono Chloro Acetic Acid obtains high-purity Mono Chloro Acetic Acid product through recrystallization.