阅读说明：本技术 丁酰氯的工业制备中的釜残留物的处理方法 (Method for treating kettle residue in industrial preparation of butyryl chloride ) 是由 聂强 赵庆瑞 于 2019-03-21 设计创作，主要内容包括：本发明公开了一种处理由丁酸和三氯化磷合成丁酰氯的丁酰氯釜残留物的方法,所述方法在工业上简便可行,高转化率地处理丁酰氯蒸馏釜残留物,并同时副产香料级的丁酸的酯。(The invention discloses a method for treating butyryl chloride still residue in the synthesis of butyryl chloride from butyric acid and phosphorus trichloride, which is simple, convenient and feasible in industry, treats the butyryl chloride still residue with high conversion rate, and produces a byproduct of perfume-grade butyric acid ester.)

1. A method for processing butyryl chloride kettle residues for synthesizing butyryl chloride from butyric acid and phosphorus trichloride comprises the following steps:

1) adding alcohol into the residue to react;

2) stopping the reaction when the residue in the kettle does not release heat any more, stirring and distilling the reaction solution; and

3) optionally, the organic phase obtained by distillation is subjected to a further separation and the separated alcohol is returned to step 1).

2. The treatment method according to claim 1, wherein the alcohol used is an alcohol having 1 to 4 carbon atoms.

3. The process according to claim 1 or 2, wherein the alcohol used is one or more selected from methanol, ethanol, propanol and butanol.

4. A process as claimed in any one of claims 1 to 3, wherein the alcohol used is ethanol.

5. The process according to claim 4, wherein the ethanol is added in an amount ranging from 40 to 80% by weight, preferably from 40 to 60% by weight, relative to the weight of the still residue.

6. The process of claim 1, wherein the alcohol is methanol and is added in an amount ranging from 28 to 56% by weight, preferably 28 to 42% by weight, relative to the weight of the still residue.

7. The process of claim 1, wherein the alcohol is propanol, which is added in an amount ranging from 52 to 104 wt.%, preferably from 52 to 78 wt.%, relative to the weight of the kettle residue.

8. The process of claim 1, wherein the alcohol is butanol and is added in an amount ranging from 64 to 128% by weight, preferably from 64 to 96% by weight, relative to the weight of the still residue.

9. The process of any one of claims 1 to 8, wherein the temperature of the reaction of step 1) in the process is controlled by cooling to not higher than 50 ℃.

Technical Field

The invention relates to the field of organic synthesis and chemical three-waste treatment, in particular to a method for treating kettle residues in the industrial preparation of butyryl chloride.

Background

Butyryl chloride is an important organic synthesis intermediate, and is mainly used for preparing butylbenzene and medicines such as diuretic acidum, dyclonine and clevidipine butyrate. Butyryl chloride, also known as chlorobutyryl, n-butyryl chloride, is a colorless, transparent liquid with an irritating odor and acid odor, boiling at 102 ℃, miscible with ethers, decomposing in water or alcohols, flammable and corrosive.

At present, the butyryl chloride which is common in industry is prepared by reacting butyric acid with a chlorinating agent, wherein the common chlorinating agent comprises: thionyl chloride, phosphorus trichloride and phosphorus pentachloride. The literature reports synthesis methods such as thionyl chloride chlorination, phosgene chlorination, and bis (trichloromethyl) carbonate chlorination.

The preparation method commonly used in industry in China is to react butyric acid with phosphorus trichloride to synthesize butyryl chloride and simultaneously produce phosphorous acid as a byproduct, and the reaction equation is as follows:

3CH₃CH₂CH₂COOH+PC|₃→3CH₃CH₂CH₂COCI+H₃PO₃

the following can be given as specific examples of the common production process for synthesizing butyryl chloride from butyric acid and phosphorus trichloride: pumping quantitative n-butyric acid into a reaction kettle at normal temperature, controlling the temperature to be about 40 ℃ under stirring, and dropwise adding phosphorus trichloride; after the dropwise addition is finished, heating to 60 ℃, preserving heat for 4 hours, standing and layering the reaction solution, and removing phosphorous acid on the lower layer; transferring the upper layer reaction liquid to a distillation kettle, distilling at normal pressure, and collecting 95-115 ℃ fractions; the kettle residue was discharged as a black viscous oily substance with a strong acid odor. Generally, about 0.15 tons of black, viscous, oily kettle residue is produced per ton of n-butyryl chloride product in the process. At present, the domestic production of butyryl chloride is about 8000 tons/year, and thus about 1200 tons of still residue are produced.

Most enterprises dispose the kettle residues with acid odor in dangerous waste, and the corresponding treatment cost is higher. Because the kettle residues have strong acid and odor and are easily emitted into the air in the processes of transportation, storage and disposal to cause environmental pollution, a hazardous waste disposal unit is not willing to receive the kettle residues, and the great waste of resources is caused.

Disclosure of Invention

In view of the above problems that the still residue of butyryl chloride prepared by the current production process emits foul odor, affects the environment and is difficult to handle, the present inventors have conducted extensive studies and attempts to obtain a method for industrially treating the still residue of butyryl chloride in the industrial preparation thereof, which is simple and feasible. It has been surprisingly found that the process of the present invention can also co-produce a fragrance grade ester of butyric acid, such as ethyl butyrate, while treating the still residue to be odorless. The method not only solves the problem of environmental pollution caused by acid odor of the kettle residues, but also brings higher economic value.

Specifically, the method of the invention is directed to an industrial preparation process for synthesizing butyryl chloride by reacting butyric acid with phosphorus trichloride. Among the still residue obtained in the preparation process, the present inventors have unexpectedly found that not only can n-butyric acid produced by the hydrolysis of butyryl chloride and butyryl chloride, which generate acid odor, be eliminated but also esters of butyric acid, which are economically valuable as essences having fruit flavors widely used, be by-produced when the still residue is treated with alcohol.

In the preparation method for synthesizing butyryl chloride by reacting butyric acid with phosphorus trichloride, the generated kettle residue is black viscous oily, and the composition of the kettle residue cannot be easily determined due to difficult separation and complex components of the kettle residue. Although it is estimated that the odor of the still residue may be derived in part from both of the butyryl chloride which is not purified completely and the butyric acid which is not reacted completely, since phosphorous acid, tar-like substances and a large amount of other impurities and the like are also present in the still residue, there is no clear direction of feasibility for the treatment of the still residue from the viewpoint of theoretical analysis.

After a plurality of schemes and experimental verification, the inventor finds that when alcohol, especially alcohol with 1-4 carbon atoms is mixed with the kettle residue in the temperature range of not higher than 50 ℃, reaction can occur between the alcohol and the kettle residue, and when distillation is carried out after the reaction is completed, the amount of residual black viscous kettle residue can be effectively reduced, and the odor of the residual kettle residue can be basically eliminated. Meanwhile, the organic phase obtained by distillation contains butyric acid ester and a part of alcohol added initially through detection, the butyric acid ester is further separated, the purity is higher, and the aromatic grade quality standard can be achieved.

The invention provides a method for processing butyryl chloride kettle residues for synthesizing butyryl chloride from butyric acid and phosphorus trichloride, which comprises the following steps:

1) adding alcohol into the residue to react;

2) stopping the reaction when the residue in the kettle does not release heat any more, stirring and distilling the reaction solution; and

3) optionally, the organic phase obtained by distillation is subjected to a further separation and the separated alcohol is returned to step 1).

In the treatment method of the present invention, the alcohol used is preferably a monohydric alcohol, a dihydric alcohol or a polyhydric alcohol having 1 to 4 carbon atoms, such as methanol, ethanol, propanol or butanol, and more preferably, the alcohol is ethanol. When the alcohol is ethanol, the amount of ethanol added is preferably in the range of 40 to 80% by weight, more preferably 40 to 60% by weight, relative to the weight of the still residue.

Accordingly, when the alcohol is methanol, the amount of methanol added is preferably in the range of 28 to 56% by weight, more preferably 28 to 42% by weight, relative to the weight of the still residue.

When the alcohol is propanol, the amount of propanol added is preferably in the range of 52-104 wt.%, more preferably in the range of 52-78 wt.%, relative to the weight of the kettle residue.

When the alcohol is butanol, it is preferably added in an amount ranging from 64 to 128% by weight, more preferably from 64 to 96% by weight, relative to the weight of the still residue.

In the treatment process of the present invention, the alcohol is slowly added and, preferably, the reaction temperature in step 1) is controlled by cooling to not higher than 50 ℃, preferably to a temperature in the range of 20 to 50 ℃.

Without being bound by theory, the inventors believe that in step 1) of the above process, there may be a reaction of the alcohol with the butyryl chloride and butyric acid in the still residue, as exemplified by the alcohol used being ethanol:

the butyryl chloride has stronger reaction activity and can directly react with absolute ethyl alcohol to generate ethyl butyrate. However, butyric acid is difficult to directly react with ethanol due to insufficient reactivity, and needs to react with ethanol under the catalysis of Lewis acid. Surprisingly, in the present invention, since hydrogen chloride is by-produced from butyryl chloride and ethanol during the esterification reaction, and the hydrogen chloride can also be used as a catalyst for catalyzing the reaction of butyric acid and ethanol, the present invention can treat butyric acid possibly existing in the residue of the reactor without adding any Lewis acid. This allows the cost of the process of the invention to be greatly reduced and the related esters of butyric acid to be obtained in high yields. Also, without being bound by theory, the inventors hypothesize that the phosphorous acid present in the kettle residue may also act as a catalyst for the reaction of butyric acid and alcohol.

The present inventors have also found that by appropriately controlling the amount of alcohol, for example, by using ethanol in a range of 40 to 80 wt%, more preferably 40 to 60 wt%, relative to the weight of the still residue, the substances causing malodor in the still residue can be substantially removed, and the ester of butyric acid can be by-produced, achieving a series of objects of waste reduction, malodor removal, resource utilization, economic value creation by-products, and the like.

In embodiments of the present invention, butyryl chloride still residue can be partially converted into, for example, methyl butyrate, ethyl butyrate, propyl butyrate and butyl butyrate by using different alcohols, such as methanol, ethanol, propanol and butanol, wherein ethyl butyrate is a widely used fruit-flavored essence, widely used in food flavors and cosmetic formulations, and can be formulated with a variety of fruit-flavored essences and other flavored essences.

In a preferred embodiment, according to the treatment method of the invention, a certain amount of butyryl chloride kettle residues are pumped into a reaction kettle under vacuum, anhydrous ethanol is added dropwise at normal temperature, cooling water is started to control the reaction temperature to be below 50 ℃, when the reaction does not release heat any more, the reaction is kept and stirred for 1 hour, ethyl butyrate and excessive ethanol are evaporated under reduced pressure, distillate is washed by sodium bicarbonate aqueous solution and water, a fruit-flavored ethyl butyrate product is obtained, and the product purity is over 99% by GC detection. If the product contains a small amount of ethanol, the washing times can be increased or the ethyl butyrate product with the GC purity of 99.9 percent can be obtained by rectification separation.

Generally, after the treatment by the method of the present invention, for example, absolute ethyl alcohol is used as the alcohol used, the butyryl chloride still residue can be reduced by 70-75%, absolute ethyl alcohol can be consumed by 0.6-0.7 ton/ton still residue, and perfume-grade ethyl butyrate can be produced by 0.50-0.60 ton/ton product. According to the treatment cost of the kettle residues of 5,000 yuan/ton, the absolute ethyl alcohol of 7,000 yuan/ton and the ethyl butyrate of 30,000 yuan/ton, the treatment method can reduce the kettle residues by 75 percent, eliminate odor pollution sources, directly reduce the economic benefit of 14,300-16,800 yuan/ton, and reduce the production cost of 2,527 yuan/ton (calculated according to the average generation of 0.15 ton by-product of each ton of butyryl chloride) by converting into the production cost of the butyryl chloride. This brings about a remarkably improved economic benefit for the industrial production of butyryl chloride.

The following are non-limiting examples of the present invention, which are given for the purpose of illustration only and are not to be construed as limiting the invention. Those skilled in the art will appreciate that numerous changes and modifications may be made to the invention without departing from the spirit and scope thereof. The starting reagents used are all commercially available unless otherwise specified.

Examples