A low-cost method for synthesizing 5-chloro-1-indanone

Abstract

The present invention relates to the technical field of chemical synthesis, and in particular to a method for synthesizing 5-chloro-1-indanone at low cost. The method of the present invention uses 3,4-dichloropropiophenone as a raw material and a chloroaluminate ionic liquid as a catalyst, and a temperature reaction is performed to obtain a crude 5-chloro-1-indanone product; the crude 5-chloro-1-indanone product is purified by activated carbon decolorization to obtain a high-content 5-chloro-1-indanone; wherein, the chloroaluminate ionic liquid is obtained as follows: aluminum chloride is added to a mixed system of an organic solvent A and an organic halide, and the temperature of the addition process control system is below 10 ° C. After the addition of aluminum chloride is completed, the temperature is increased to 85 ° C for insulation, and then the temperature is lowered and the stratification is allowed to proceed, and the lower layer is the chloroaluminate ionic liquid. The present invention greatly reduces production costs, improves product quality, and is very environmentally friendly and efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and in particular to a method for synthesizing 5-chloro-1-indanone at low cost. Background Art

[0002] Indoxacarb has a unique mechanism of action, and is highly effective, broad-spectrum, safe to use, and harmless to humans, animals, and natural enemies. It can overcome or delay the development of pesticide resistance in pests. It can also be made into a compound insecticide with emamectin benzoate and pyridazinphos-methyl, with obvious synergistic effects. It has been a hot topic of research in the field of insecticides in recent years.

[0003] 5-Chloro-1-indanone is an important intermediate in the synthesis of indoxacarb. Its molecular formula is C9H7ClO, its relative molecular weight is 166, and its structural formula is .

[0004] Currently, the synthesis method of 5-chloro-1-indanone mainly uses 3,4-dichloropropiophenone as the raw material and aluminum chloride as the catalyst to produce it through Friedel-Crafts alkylation reaction under high temperature conditions. For example, the Chinese invention patent application "A Production Method of 5-chloro-1-indanone" (Patent Publication No.: CN103601625A) uses 3,4-dichloropropiophenone as the raw material and aluminum chloride as the catalyst to synthesize 5-chloro-1-indanone under high temperature conditions, but the yield is low, and the post-processing will produce a large amount of aluminum-containing wastewater and tar, and the environmental protection treatment cost is high. In addition, the Chinese invention patent "A method for synthesizing 5-chloro-1-indanone" (patent announcement number: CN113087609B) discloses a method for generating 5-chloro-1-indanone by intramolecular cyclization using 1-(4-chlorophenyl)-2-propen-1-one as a raw material under the catalysis of hydrogen chloride. The raw material 1-(4-chlorophenyl)-2-propen-1-one used in this method is difficult to obtain and is expensive, which is not conducive to industrial production.

[0005] Therefore, it is particularly important to find an economical and environmentally friendly method for synthesizing 5-chloro-1-indanone. Summary of the Invention

[0006] In response to the technical problems of high environmental treatment costs and high raw material costs in existing 5-chloro-1-indanone synthesis processes, the present invention provides a low-cost method for synthesizing 5-chloro-1-indanone. 3,4-dichloropropiophenone is used as a raw material, chloroaluminate ionic liquid is used as a catalyst, and a Friedel-Crafts alkylation reaction is carried out under high temperature conditions to produce crude 5-chloro-1-indanone. The crude 5-chloro-1-indanone is then purified to produce a high-content 5-chloro-1-indanone. This method greatly reduces production costs, improves product quality, and is very environmentally friendly and efficient.

[0007] The technical solutions of the present invention are as follows:

[0008] A low-cost method for synthesizing 5-chloro-1-indanone comprises using 3,4-dichloropropiophenone as a raw material and a chloroaluminate ionic liquid as a catalyst to react at elevated temperature to obtain a crude 5-chloro-1-indanone product; the crude 5-chloro-1-indanone product is then decolorized and purified with activated carbon to obtain a high-content 5-chloro-1-indanone.

[0009] Chloroaluminate ionic liquids were obtained as follows:

[0010] Aluminum trichloride is added to a mixed system of organic solvent A and organic halide, and the system temperature is controlled to be below 10°C during the addition process. After the addition of aluminum trichloride is completed, the temperature is raised to 80-85°C and kept warm, then the temperature is lowered and allowed to stand for stratification, and the lower layer is the chloroaluminate ionic liquid.

[0011] Furthermore, the organic solvent A includes one or more of toluene, dichloroethane, dichloromethane, and n-heptane.

[0012] Furthermore, the organic halide includes one or more of 1-ethyl-3-methylimidazole chloride, 1-ethyl-3-methylimidazole bromide, 1-ethylpyridinium chloride, and 1-ethylpyridinium bromide.

[0013] Furthermore, the molar ratio of aluminum chloride to the organic halide is 1:0.1 to 1:2, preferably 1:0.1 to 1:1.

[0014] Aluminum trichloride is the main component of ionic liquid. When the molar ratio of aluminum trichloride to organic halide is X>0.5, the main component formed in the ionic liquid is Al2Cl7 - , showing strong Lewis acidity, which is more conducive to catalyzing the Friedel-Crafts alkylation reaction; when the molar ratio of aluminum chloride to organic halide is X<0.5, the trivalent aluminum in the ionic liquid is only in the form of AlC14 - The other anion is Cl - , relative to AlC13, the excess Cl - It is a weak base, so although it is classified as an acidic ionic liquid, it can behave as a weak base. When the molar ratio of aluminum chloride to organic halide is X=0.5, the trivalent aluminum in the ionic liquid is mainly in the form of AlC14 - exists in the form of Cl - The alkalinity of aluminum chloride and the acidity of AlC13 are neutral; therefore, when the molar ratio X of aluminum chloride and organic halide is greater than 0.5, the catalytic effect is best.

[0015] Furthermore, after the addition of aluminum chloride is completed, the temperature is maintained for 60-65 minutes, and then the temperature is raised to 80-85° C. and maintained for 3-3.5 hours.

[0016] Furthermore, the molar ratio of 3,4-dichloropropiophenone to the organic halide in the chloroaluminate ionic liquid is 1:0.1 to 1:0.8.

[0017] Furthermore, the reaction temperature of 3,4-dichloropropiophenone and chloroaluminate ionic liquid is 80-120° C., preferably 90-100° C.; and the reaction time is 5-15 h, preferably 5-10 h.

[0018] Furthermore, the activated carbon decolorization and purification step is specifically as follows: adding organic solvent B to the crude 5-chloro-1-indanone, standing for stratification, recovering the chloroaluminate ionic liquid, adding activated carbon to the 5-chloro-1-indanone liquid for decolorization, filtering the activated carbon to remove part of the organic solvent, cooling the filtrate for crystallization, filtering, and drying to obtain a high-content 5-chloro-1-indanone.

[0019] Furthermore, the organic solvent B includes one or more of toluene, dichloroethane, dichloromethane, and n-heptane, preferably toluene or n-heptane.

[0020] Furthermore, the mass ratio of 3,4-dichloropropiophenone to activated carbon is 1:0.01 to 1:0.1, preferably 1:0.03 to 1:0.05.

[0021] Furthermore, the decolorization temperature is 40~60°C, and the decolorization time is 0.5~2h.

[0022] Furthermore, the activated carbon obtained by filtration after decolorization is treated as solid waste.

[0023] Furthermore, the chloroaluminate ionic liquid is recycled 1 to 5 times, preferably 3 to 4 times.

[0024] The beneficial effects of the present invention are:

[0025] The present invention uses ionic liquid to prepare 5-chloro-1-indanone, which has low reaction temperature and high yield.

[0026] The preparation method of ionic liquid is simple. Compared with conventional aluminum chloride catalyst, ionic liquid catalyst has stable activity, is reusable, low cost, can meet the needs of large-scale industrial production, and can reduce the generation of three wastes;

[0027] The process flow of the invention is simple, and the reaction conditions are milder than those of conventional reactions. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0029] Example 1

[0030] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 3.4 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 80 ° C, and the reaction was kept warm for 15 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of n-heptane was added, and after the system was completely dissolved, the magnetic stirring was turned off, and it was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system and added). After the addition of water, there was a temperature rise in the early stage). After the addition was completed, the mixture was stirred for 30 minutes, the magnetic stirring was turned off, and the mixture was allowed to stand for 30 minutes. The waste water at the bottom was separated and the liquid was cut out. After the separation was completed, 2.5 g of activated carbon was added, the temperature was raised to 50°C, and the mixture was stirred for 2 hours. After filtering the activated carbon (treated as solid waste), the filtrate was subjected to negative pressure desolventizing. After the system in the bottle became turbid, the desolventizing was stopped, the system was cooled to 0-5°C, 5-chloro-1-indanone precipitated, and suction filtration was performed to obtain off-white crystals. After drying, 13.2 g of 5-chloro-1-indanone was obtained, with a content of 98.5% and a yield of 64.7%.

[0031] The chloroaluminate ionic liquid used was obtained as follows:

[0032] Step 1: Add 50 g of toluene solution to a 250 mL four-necked flask, then add 1.8 g of 1-ethyl-3-methylimidazole chloride and start stirring;

[0033] Step 2: Under nitrogen protection, 1.6 g of aluminum trichloride was added in three batches. The system temperature was controlled below 10 ° C. The addition time was controlled within 20 min. After the addition was completed, the mixture was kept warm for 1 h, then gradually heated to 85 ° C. and kept warm for 3 h to obtain a mixture of ionic liquid and toluene. The mixture was cooled and allowed to stand for stratification. The lower layer was the chloroaluminate ionic liquid.

[0034] Example 2

[0035] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 14 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 100 ° C, and the reaction was kept warm for 10 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of dichloromethane was added, and after the system was completely dissolved, the magnetic stirring was turned off, and it was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid remained in the system. When water was added, there was a rise in the early stage). Temperature phenomenon), after the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the liquid; the cut liquid is added to a 500 mL four-necked flask, and then 1.75 g of activated carbon is added, the temperature is raised to 55°C, and stirred for 2 hours. After filtering the activated carbon (treated as solid waste), the filtrate is subjected to negative pressure desolventizing. After observing that the system in the flask becomes turbid, the desolventizing is stopped, the system is cooled to 0~5°C, 5-chloro-1-indanone is precipitated, and suction filtration is performed to obtain off-white crystals. After drying, 16.5 g of 5-chloro-1-indanone is obtained, with a content of 98.8% and a yield of 81.1%.

[0036] The chloroaluminate ionic liquid used was obtained as follows:

[0037] Step 1: Add 50 g of n-heptane solution to a 250 mL four-necked flask, then add 7.5 g of 1-ethyl-3-methylimidazole chloride and start stirring;

[0038] Step 2: Under nitrogen protection, add 6.5 g of aluminum trichloride in three batches. The system temperature is controlled below 10 ° C. The addition time is controlled within 25 minutes. After the addition is completed, keep warm for 1 hour, then gradually increase the temperature to 80 ° C. and keep warm for 3 hours to obtain a mixture of ionic liquid and n-heptane. Cool 30 ± 2 ° C and let stand to separate. The lower layer is the chloroaluminate ionic liquid.

[0039] Example 3

[0040] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 15.5 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath was heated to 110 ° C, and the reaction was kept warm for 8 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of dichloroethane was added, and after the system was completely dissolved, the magnetic stirring was turned off, and it was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, and when water was added, the temperature rose in the early stage). phenomenon), after the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, separate the liquid and cut out the feed; add the cut feed liquid to a 500mL four-necked flask, then add 1.255g of activated carbon, raise the temperature to 50°C, stir for 30 minutes, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the flask becomes turbid, stop desolventizing, cool the system to 0~5°C, 5-chloro-1-indanone precipitates, and filter to obtain off-white crystals. After drying, 16.9g of 5-chloro-1-indanone is obtained, with a content of 98.8% and a yield of 83%.

[0041] The chloroaluminate ionic liquid used was obtained as follows:

[0042] Step 1: Add 50 g of dichloromethane solution to a 250 mL four-necked flask, then add 7.4 g of 1-ethylpyridine chloride and start stirring;

[0043] Step 2: Under nitrogen protection, 8.1 g of aluminum trichloride was added in three batches. The system temperature was controlled below 10 ° C. The addition time was controlled within 25 min. After the addition was completed, the mixture was kept warm for 60 min, then gradually heated to 83 ° C. and kept warm for 3.3 h to obtain a mixture of ionic liquid and dichloromethane. The mixture was cooled by 30 ± 2 ° C and allowed to stand for stratification. The lower layer was the chloroaluminate ionic liquid.

[0044] Example 4

[0045] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 22.2 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 120 ° C, and the reaction was kept warm for 5 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of dichloromethane was added, and after the system was completely dissolved, the magnetic stirring was turned off and the system was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The system temperature was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, When water is added, there is a temperature rise in the early stage). After the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the waste water at the bottom; after the separation is completed, add 1.25g of activated carbon, raise the temperature to 45°C, stir for 2h, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the bottle becomes turbid, stop desolventizing, cool the system to 0~5°C, and 5-chloro-1-indanone precipitates. Filter it to obtain off-white crystals, which are dried to obtain 16g of 5-chloro-1-indanone with a content of 98.8% and a yield of 78.6%.

[0046] The chloroaluminate ionic liquid used was obtained as follows:

[0047] Step 1: Add 50 g of dichloroethane solution to a 250 mL four-necked flask, then add 9.3 g of 1-ethylpyridinium bromide and start stirring;

[0048] Step 2: Under nitrogen protection, 13 g of aluminum trichloride was added in three batches. The system temperature was controlled below 10 ° C. The addition time was controlled within 30 min. After the addition was completed, the mixture was kept warm for 1 h, then gradually heated to 85 ° C. and kept warm for 3 h to obtain a mixture of ionic liquid and dichloroethane. The mixture was cooled by 30 ± 2 ° C and allowed to stand for stratification. The lower layer was the chloroaluminate ionic liquid.

[0049] Example 5

[0050] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 13.9 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 90 ° C, and the reaction was kept warm for 8 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of toluene was added, and after the system was completely dissolved, the magnetic stirring was turned off, and the system was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, and the addition was carried out). When the solution is added to the water, there is a temperature rise in the early stage). After the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the liquid to cut out the waste water at the bottom; after the separation is completed, add 0.25g of activated carbon, raise the temperature to 50℃, stir for 1h, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the bottle becomes turbid, stop desolventizing, cool the system to 0~5℃, and 5-chloro-1-indanone precipitates. Filter it to obtain off-white crystals. After drying, 16g of 5-chloro-1-indanone is obtained with a content of 96% and a yield of 76.4%.

[0051] The chloroaluminate ionic liquid used was obtained as follows:

[0052] Step 1: Add 50 g of toluene solution to a 250 mL four-necked flask, then add 5.8 g of 1-ethylpyridinium bromide and start stirring;

[0053] Step 2: Under nitrogen protection, 8.1 g of aluminum trichloride was added in three batches. The system temperature was controlled below 10°C and the addition time was controlled within 30 min. After the addition was completed, the mixture was kept warm for 1 h, then gradually heated to 85°C and kept warm for 3 h to obtain a mixture of ionic liquid and toluene. The mixture was cooled by 30±2°C and allowed to stand for stratification. The lower layer was the chloroaluminate ionic liquid.

[0054] Example 6

[0055] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 13.9 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 100 ° C, and the reaction was kept warm for 7 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of toluene was added, and after the system was completely dissolved, the magnetic stirring was turned off, and the system was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, and the addition was carried out). When adding water, there is a temperature rise phenomenon in the early stage). After the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the liquid to cut out the waste water at the bottom; after the separation is completed, add 1g of activated carbon, raise the temperature to 50℃, stir for 90 minutes, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the bottle becomes turbid, stop desolventizing, cool the system to 0~5℃, and 5-chloro-1-indanone precipitates. Filter it to obtain off-white crystals. After drying, 17.9g of 5-chloro-1-indanone is obtained, with a content of 99% and a yield of 88.1%.

[0056] The chloroaluminate ionic liquid used was the first use of the chloroaluminate ionic liquid recovered in Example 5.

[0057] Example 7

[0058] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 13.9 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath was heated to 110 ° C, and the reaction was kept warm for 7 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of toluene was added, and after the system was completely dissolved, the magnetic stirring was turned off, and the system was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, and the addition was carried out). When adding water, there is a temperature rise phenomenon in the early stage). After the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the liquid to cut out the waste water at the bottom; after the separation is completed, add 1g of activated carbon, raise the temperature to 55℃, stir for 30 minutes, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the bottle becomes turbid, stop desolventizing, cool the system to 0~5℃, and 5-chloro-1-indanone precipitates. Filter it to obtain off-white crystals. After drying, 17.4g of 5-chloro-1-indanone is obtained, with a content of 99% and a yield of 85.7%.

[0059] The chloroaluminate ionic liquid used was the third use of the chloroaluminate ionic liquid recovered in Example 5.

[0060] Example 8

[0061] 25 g of 3,4-dichloropropiophenone was put into a 500 mL four-necked flask, 13.9 g of chloroaluminate ionic liquid was added, magnetic stirring was turned on, the oil bath temperature was raised to 100 ° C, and the reaction was kept warm for 7 hours. After sampling and testing, the temperature was lowered to 40 ° C, 100 g of toluene was added, and after the system was completely dissolved, the magnetic stirring was turned off, and the system was allowed to stand for 30 minutes. The ionic liquid at the bottom was separated and cut out (recovery and application), magnetic stirring was turned on, and then 100 g of deionized water was slowly added. The temperature of the system was controlled to be below 50 ° C during the addition process (a small amount of ionic liquid was left in the system, and the addition was carried out). When adding water, there is a temperature rise phenomenon in the early stage). After the addition is completed, stir for 30 minutes, turn off the magnetic stirring, let it stand for 30 minutes, and separate the liquid to cut out the waste water at the bottom; after the separation is completed, add 1g of activated carbon, raise the temperature to 50℃, stir for 30 minutes, filter the activated carbon (treat it as solid waste), and perform negative pressure desolventizing on the filtrate. After observing that the system in the bottle becomes turbid, stop desolventizing, cool the system to 0~5℃, and 5-chloro-1-indanone precipitates. Filter it to obtain off-white crystals. After drying, 16.5g of 5-chloro-1-indanone is obtained, with a content of 99% and a yield of 81.2%.

[0062] The chloroaluminate ionic liquid used was the fifth use of the chloroaluminate ionic liquid recovered in Example 5.

[0063] Comparative Example 1

[0064] 25 g of 3,4-dichloropropiophenone was placed in a 500 mL four-necked flask, and 13.9 g of triethylamine hydrochloride ionic liquid was added. The magnetic stirring was turned on, and the oil bath was heated to 100°C. After the reaction was kept warm for 7 hours, a sample was taken for testing and the mixture was cooled to 40°C. 100 g of toluene was added. After the system was completely dissolved, the magnetic stirring was turned off and the mixture was allowed to stand for 30 minutes. No stratification was observed.

[0065] Take another four-necked flask, add 500g of water, turn on magnetic stirring, and slowly add the reaction solution after adding toluene to the water. The temperature of the addition process control system is below 50°C, and the addition rate is controlled to be completed within 20-30min. The system releases a large amount of hydrochloric acid gas. After the addition is completed, stir for 30min, turn off the magnetic stirring, let it stand for 30min, and separate the waste water at the bottom; after the separation is completed, add 1g of activated carbon, heat to 50°C, stir for 90min, filter the activated carbon (as solid waste treatment), and perform negative pressure desolvation on the filtrate. After observing that the system in the bottle becomes turbid, stop desolvation, cool the system to 0~5°C, 5-chloro-1-indanone precipitates, and filter to obtain off-white crystals. After drying, 16.8g of 5-chloro-1-indanone is obtained, with a content of 96.5% and a yield of 75.8%.

[0066] The triethylamine hydrochloride ionic liquid used was obtained as follows:

[0067] Step 1: Add 50 g of dichloromethane solution to a 250 mL four-necked flask, then add 5.8 g of triethylamine hydrochloride and start stirring;

[0068] Step 2: Under nitrogen protection, add 8.1 g of aluminum trichloride in three batches. The system temperature is controlled below 10°C and the addition speed is slow. After the addition is completed, keep warm for 1 hour, then gradually increase the temperature to 85°C and keep warm for 3 hours to obtain a mixture of ionic liquid and dichloromethane. Cool and let stand to separate the layers. The lower layer is triethylamine hydrochloride ionic liquid.

[0069] Comparative example 1 uses triethylamine hydrochloride acidic ionic liquid, adds solvent toluene to reaction system during the reaction, compare with Example 6, comparative example 1 ionic liquid, product and solvent can not be effectively separated after the reaction is completed, ionic solution cannot be recovered using the extraction method of the present invention, so system contains a large amount of ionic liquid, and ionic liquid contains a large amount of aluminum chloride, although 100g water can destroy aluminum chloride in ionic liquid, aluminum ion can not be cleaned, therefore comparative example 1 needs to use 500g water to wash aluminum ion out in system to ensure that the content of output product is qualified, the method generates a large amount of aluminum-containing wastewater, and aluminum content is more in the aluminum-containing wastewater generated, wastewater treatment is more complicated and causes production cost to increase, while ionic liquid can not be recycled, greatly increases raw material cost, is unfavorable for industrialized production, yield is compared with embodiment 6 of identical reaction conditions low about 10%, causes production cost to increase. Contrast can be seen that the present invention adds organic solvent after the reaction is completed and ionic liquid is extracted and applied mechanically, effectively avoids the large amount of generation of wastewater, alleviates environmental pressure, and the yield of product is also higher.

[0070] At the same time, it was found from Comparative Example 1 that not all ionic liquids can be recovered using the extraction method of the present invention. Experiments have verified that alkyl quaternary phosphonium ionic liquids and alkyl quaternary ammonium ionic liquids are both homogeneous in the extraction stage. The triethylamine hydrochloride ionic liquid used in Comparative Example 1 is a type of alkyl quaternary ammonium ionic liquid. However, alkyl-substituted imidazole ionic liquids and alkyl-substituted pyridinium ionic liquids proposed in the present invention have cyclic structures (imidazole ring and pyridine ring structures). They have low miscibility with organic solvents and products during extraction, and can be recovered in the post-processing stage using the extraction method of the present invention.

[0071] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and substance of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any changes or substitutions that can be readily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. A method for synthesizing 5-chloro-1-indanone, characterized in that: Using 3,4-dichloropropiophenone as raw material and chloroaluminate ionic liquid as catalyst, a temperature-raising reaction is performed to obtain a crude product of 5-chloro-1-indanone; the crude product of 5-chloro-1-indanone is decolorized and purified with activated carbon to obtain a high-content 5-chloro-1-indanone; Chloroaluminate ionic liquids were obtained as follows: Aluminum trichloride is added to a mixed system of organic solvent A and organic halide, and the system temperature is controlled to be below 10°C during the addition process. After the addition of aluminum trichloride is completed, the temperature is raised to 80-85°C and maintained, and then the temperature is lowered and allowed to stand for stratification, and the lower layer is the chloroaluminate ionic liquid; The organic halide is one or more of 1-ethyl-3-methylimidazole chloride, 1-ethyl-3-methylimidazole bromide, 1-ethylpyridinium chloride, and 1-ethylpyridinium bromide; The activated carbon decolorization and purification steps specifically include: adding an organic solvent B to a crude 5-chloro-1-indanone product, allowing the product to stand for stratification, recovering a chloroaluminate ionic liquid, adding activated carbon to the 5-chloro-1-indanone solution for decolorization, filtering the activated carbon to remove part of the organic solvent from the filtrate, cooling and crystallizing the filtrate, filtering, and drying to obtain a high-content 5-chloro-1-indanone, wherein the organic solvent B is one or more of toluene, dichloroethane, dichloromethane, and n-heptane.

2. The method according to claim 1, wherein The organic solvent A includes one or more of toluene, dichloroethane, dichloromethane, and n-heptane.

3. The method according to claim 1, wherein The molar ratio of aluminum chloride to organic halide is 1:0.1~1:2; After the addition of aluminum chloride is completed, keep the temperature for 60-65 minutes, then raise the temperature to 80-85°C and keep it for 3-3.5 hours.

4. The method according to claim 1, wherein The molar ratio of aluminum trichloride to organic halide is 1:0.1~1:

1.

5. The method according to claim 1, wherein The molar ratio of 3,4-dichloropropiophenone to the organic halide in the chloroaluminate ionic liquid is 1:0.1 to 1:0.8; The reaction temperature of 3,4-dichloropropiophenone and chloroaluminate ionic liquid is 80-120° C., and the reaction time is 5-15 h.

6. The method according to claim 1, wherein The mass ratio of 3,4-dichloropropiophenone to activated carbon is 1:0.01~1:0.1; the decolorization temperature is 40~60℃, and the decolorization time is 0.5~2h.

7. The method according to claim 1, wherein The chloroaluminate ionic liquid is recycled 1 to 5 times.