Hexachloroethane as novel acylation reagent and acyl chloride co-production technology

Abstract

The invention relates to the field of new material fine chemicals, in particular to preparation of corresponding hydrocarbyl acyl chloride and oxalyl chloride by reaction of hexachloroethane serving as a novel acylation reagent and carboxylic acid. Acyl chloride is a functional chemical material which is numerous in variety and wide in application, and the process technology has outstanding environmental friendliness and low-cost competitiveness.

Description

Technical Field

[0001] The present invention relates to the field of new material fine chemicals, and particularly to the co-production of corresponding acyl chlorides and oxalyl chloride by reacting hexachloroethane as a new acylating reagent with carboxylic acids. Acyl chlorides are functional chemical materials with a large variety and wide uses, and this process technology has outstanding environmental friendliness and low-cost competitiveness.

Background Art

[0002] Acyl chlorides are basic chemicals with a large variety and wide uses, and the environmentally friendly and low-cost preparation technologies thereof have been continuously concerned by industry technicians for a long time. The known acyl chloride manufacturing technologies usually use carboxylic acids to react with corresponding acylating reagents. Typical acylating reagents such as thionyl chloride, phosphorus trichloride, phosphorus pentachloride, oxalyl chloride, phosgene, solid phosgene, etc. all have the environmental emission pressure and high-toxicity supervision bottlenecks well-known to industry technicians, and the above-mentioned pain points in the industry have not been effectively solved for a long time.

[0003] On the other hand, traditional chlor-alkali chemical industry is large in scale and is a pillar branch field of contemporary fine chemicals. A large amount of by-product chlorine resources thereof require new technical processes to be converted into corresponding high-value-added products, and at the same time, the green recycling of chlorine resources is properly disposed of. Therefore, it is urgent to explore new resource utilization new technologies and new processes for chlorides manufactured from chlorine to empower new values, which has received strong support from national policies and regulations.

[0004] The gist of this application is that unexpectedly, a large-scale chloride product downstream of chlorine, namely hexachloroethane, can be used as a new acylating reagent to co-produce corresponding acyl chlorides and oxalyl chloride by reacting with a series of carboxylic acids. Since oxalyl chloride has a low boiling point and usually has a large difference in boiling point from the co-produced acyl chloride, the two are particularly easy to separate and purify. The previously known uses of hexachloroethane are limited to lubricating oil additives, preservatives, solvents, or organic synthesis raw materials. The process disclosed in the present invention uses hexachloroethane as a chlorine source for the first time, completely eliminating the high-emission problems of traditional acyl chloride manufacturing such as sulfur dioxide and phosphorous acid from the source, and has outstanding process safety, environmental friendliness, and comprehensive cost competitiveness.

Summary of the Invention

[0005] The present application has now found that, as shown in Reaction Formula (I), hexachloroethane reacts with a carboxylic acid compound shown in Structural Formula A under reaction conditions "conditions" to co-produce oxalyl chloride and an acyl chloride substance shown in Structural Formula B:

[0006]

[0007] Wherein carboxylic acid A contains n carboxyl functional groups, and n is an integer between 1 and 6; R is an aliphatic or aromatic hydrocarbon group containing 1 to 24 carbon atoms; and m in acyl chloride B is an integer less than or equal to n.

[0008] "conditions" refers to at least one of the conditions such as additives, light, heat, microwave, ultrasonic wave, vacuum or pressure, solvents, etc.

[0009] The additive is a catalyst, a promoter, or an inhibitor; preferably, the catalyst or the promoter is a Lewis acid or a Lewis base compound; the addition amount of the catalyst or the promoter is 0.1-1000% of the reaction raw materials; preferably 1-1000%, more preferably 1-200%, and further more preferably 1-120%.

[0010] "Light" means that the reaction system proceeds under light irradiation conditions, and the wavelength range of the light is 200-780 nanometers;

[0011] "Heat" means that the reaction system proceeds under heating conditions, and the reaction temperature is -25-450 degrees Celsius, preferably -20-400 degrees Celsius;

[0012] "Microwave or ultrasonic wave" means using a microwave or ultrasonic wave generator to irradiate the reaction system;

[0013] "Pressure" means that the reaction system proceeds under pressurized or certain vacuum conditions, and the pressure of the reaction process can be 0.001-200 atmospheres, preferably 0.01-100 atmospheres.

[0014] The solvent is selected from at least one of substituted or unsubstituted aromatic hydrocarbons, straight-chain or branched-chain aliphatic hydrocarbons, (sub) sulfones, amides, ethers, alcohols, esters, ketones, nitriles, carboxylic acids, water, amines, carbonates, ionic liquids, and supercritical carbon dioxide containing 1-24 carbons; or the substrate itself simultaneously serves as a solvent medium.

[0015] In some preferred embodiments of the present invention, the solvent is selected from at least one of water, acetonitrile, ethanol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethyl sulfone, benzyl sulfoxide, benzyl sulfone, cyclobutyl sulfoxide, sulfolane, trichlorosilane, dichloromethane, dichloroethane, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, chloroform, carbon tetrachloride, benzene, toluene, xylene, mesitylene, durene, acetonitrile, ethylbenzene, diethylbenzene, chlorobenzene, dichlorobenzene, anisole, nitrobenzene, heptane, hexane, petroleum ether, dioxane, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, diglyme, triglyme, propylene glycol methyl ether acetate, triethylamine, tributylamine, dimethylisopropylamine, pyridine, N,N-tetramethylethylenediamine, N-alkylmorpholine, N-alkylpyrrole, N,N-dimethylformamide, formylmorpholine, N,N-diethylformamide, and N-methylpyrrolidone.

[0016] The use of a solvent is preferred but not essential. Under certain conditions, the solvent may not be used, i.e., the reaction is carried out using the dissolved or molten reaction raw materials or the directly mixed reaction raw materials under heating, grinding, or gas-phase conditions; and the reaction is carried out using supercritical carbon dioxide as the reaction medium. The advantages of using supercritical carbon dioxide as the reaction medium are environmental friendliness and facilitation of the reaction and product separation, which are well-known to those skilled in the art.

[0017] Preferably, the additive or promoter in the reaction conditions is an acid; the acid is a halogen, hydrochloric acid, sulfuric acid, nitric acid, hydrohalic acid, sulfonic acid, carboxylic acid, metal or its oxide or its halide, sulfur, sulfide, oxide, carboxylate, sulfate (hydrogen) salt, nitrate, (hypo)halite. Preferably, the additive or promoter is preferably a metal or its oxide or its halide, and more preferably iron oxide or ferric chloride.

[0018] Based on raw material A, the usage amount of hexachloroethane is 0.5 - 100 equivalents, preferably 0.5 - 20 equivalents, and more preferably 0.5 - 5 equivalents.

[0019] Based on raw material A, the usage amount of the additive is a catalytic amount or an equivalent amount or an excessive amount (0.001 - 1000 equivalents).

[0020] Exemplary but non-limiting acyl chlorides prepared according to reaction formula (I) are the following structures or mixtures:

[0021]

[0022] Preferably, an exemplary but non-limiting implementation mode of reaction formula (I) is (IA), i.e., using benzoic acid substituted by R1 and hexachloroethane to react under reaction conditions to generate oxalyl chloride and substituted benzoyl chloride (where R1 takes values of hydrogen, halogen, R, OR, NHR, or NR2 groups):

[0023]

[0024] Preferably, an exemplary but non-limiting implementation mode of reaction formula (I) is (IB), i.e., using isophthalic acid as the raw material and reacting with hexachloroethane under reaction conditions to generate oxalyl chloride and isophthaloyl chloride:

[0025]

[0026] Preferably, an exemplary but non-limiting implementation mode of reaction formula (I) is (IC), i.e., using terephthalic acid as the raw material and reacting with hexachloroethane under reaction conditions to generate oxalyl chloride and terephthaloyl chloride:

[0027]

[0028] We will further illustrate in the embodiments.

Specific Embodiments

[0029] The gist of the present invention will be further illustrated below in conjunction with specific embodiments:

[0030] Embodiment:

[0031]

[0032] Add 54.5 grams of benzoic acid, 0.3 grams of anhydrous ferric chloride catalyst, 55.5 grams of hexachloroethane, and 340 milliliters of chlorobenzene solvent into a four-necked flask. The mixture system is gradually heated to the range of 120 - 125 °C and kept for reaction for 4 hours. During this period, the oxalyl chloride continuously distilled out during the reaction is condensed and collected. After completion, the mixture is distilled under normal pressure to obtain the fore-fraction oxalyl chloride, chlorobenzene solvent, and 60.1 grams of benzoyl chloride product in sequence, and 25.6 grams of oxalyl chloride is obtained by combining and collecting the reaction.

[0033] Embodiment:

[0034]

[0035] Add 100.6 grams of terephthalic acid, 0.8 grams of anhydrous ferric chloride catalyst, and 650 milliliters of o-dichlorobenzene solvent into a four-necked flask. The mixture system is heated to 90 °C, and 150.5 grams of hexachloroethane is added in batches in the range of 90 - 130 °C. The system is kept for reaction at about 125 °C for 6 hours. During this period, the oxalyl chloride distilled out during the reaction is condensed and collected. After completion, the mixture is distilled under normal pressure to remove oxalyl chloride and then converted to vacuum distillation to recover the o-dichlorobenzene solvent. The residue obtained is distilled under reduced pressure at 140 - 150 °C to obtain 117.3 grams of terephthaloyl chloride product, and 68.8 grams of oxalyl chloride is obtained by combining and collecting the reaction simultaneously.

[0036] Embodiment:

[0037]

[0038] Add 98.6 grams of isophthalic acid, 0.74 grams of anhydrous ferric chloride catalyst, and 600 milliliters of o-dichlorobenzene solvent into a four-necked flask. The mixture system is heated to 90 °C, and 154.2 grams of hexachloroethane is added in batches in the range of 90 - 130 °C. The system is kept for reaction at about 125 °C for 4 hours. During this period, the oxalyl chloride distilled out during the reaction is condensed and collected. After completion, the mixture is distilled under normal pressure to remove oxalyl chloride and then converted to vacuum distillation to recover the o-dichlorobenzene solvent. The residue obtained is distilled under reduced pressure at 130 - 140 °C to obtain 106.5 grams of isophthaloyl chloride product, and 64.0 grams of oxalyl chloride is obtained by combining and collecting the reaction simultaneously.

[0039] It should be emphasized that the above embodiments are merely illustrative rather than restrictive. Based on the disclosure of this application, any adjustments or changes to reaction conditions, parameters, etc. that are commonly adopted by any person skilled in the art will not deviate from the gist of the present invention. The scope of protection of this patent shall be subject to the relevant claims.

Claims

1. A process technology for co-producing acyl chloride and oxalyl chloride with hexachloroethane as an acylating reagent, as shown in reaction formula (I). Under reaction conditions, hexachloroethane and a carboxylic acid compound shown in structural formula A react to co-produce oxalyl chloride and an acyl chloride substance shown in structural formula B: Among them, carboxylic acid A contains n carboxyl functional groups, where n is an integer between 1 and 6; R is an aliphatic or aromatic hydrocarbon group containing 1 to 24 carbon atoms; and m in acyl chloride B is an integer less than or equal to n. Reaction conditions refer to at least one of the conditions such as additives, light, heat, microwave, ultrasonic wave, vacuum or pressure, and solvents.

2. According to claim (1), the catalyst or promoter in the involved conditions is a Lewis acid compound; the addition amount of the catalyst or promoter is 0.1 - 1000% of the reaction raw materials; preferably 1 - 1000%, more preferably 1 - 200%, and further more preferably 1 - 120%. Light means that the reaction system proceeds under light irradiation conditions, and the wavelength range of the light is 200 - 780 nanometers. Heat means that the reaction system proceeds under heating conditions, and the reaction temperature is -25 - 450 °C, preferably -20 - 400 °C. Microwave or ultrasonic wave means irradiating the reaction system with a microwave or ultrasonic wave generator. Pressure means that the reaction system proceeds under pressurized or certain vacuum conditions, and the pressure of the reaction process can be 0.001 - 200 atmospheres, preferably 0.01 - 100 atmospheres. Solvents are aromatic or aliphatic hydrocarbons, halogenated aromatic or aliphatic hydrocarbons, or various esters, alcohols, ethers, nitriles, ketones, amides, sulfones, carbonates, or water, or emerging so-called green solvents such as "ionic liquids" or supercritical carbon dioxide (Supercritical CO2); or a mixed solvent system of any two or more of the above.

3. According to claims (1 and 2), preferably, the additive or promoter in the reaction conditions is an acid; the acid is a halogen, hydrochloric acid, sulfuric acid, nitric acid, hydrohalic acid, sulfonic acid, carboxylic acid, metal or its oxide or its halide, sulfur, sulfide, oxide, carboxylate, sulfate (hydrogen) salt, nitrate, (hypo)halite.

4. According to claim (1), exemplary but non-limiting acyl chlorides prepared according to reaction general formula (I) are the following structures or mixtures:

5. According to claim (1), a preferred implementation mode of reaction general formula (I) is (IA), that is, using benzoic acid substituted by R1 and hexachloroethane to react under reaction conditions to generate oxalyl chloride and substituted benzoyl chloride (R1 takes values of hydrogen, halogen, R, OR, NHR, or NR2 group):

6. According to claim (1), a preferred implementation mode of reaction general formula (I) is (IB), that is, using isophthalic acid as a raw material and hexachloroethane to react under reaction conditions conditions to generate oxalyl chloride and isophthaloyl chloride:

7. According to claim (1), a preferred implementation mode of reaction general formula (I) is (IC), that is, using terephthalic acid as a raw material and hexachloroethane to react under reaction conditions conditions to generate oxalyl chloride and terephthaloyl chloride:

8. The application of oxalyl chloride and acyl chloride prepared by the process technology of the present invention as raw materials in downstream organic synthesis or synthetic materials according to claims (1-7).

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