Chemical structures and preparation methods of pyrogallol and dimer diphenyl ether tetraphenol thereof

Abstract

The invention belongs to the field of new materials of fine chemicals, high-efficiency preparation of the pyrogallol is realized in a water phase through a chemical synthesis method by taking tetra-halogen substituted cyclohexanone as a raw material, and the method can effectively reduce the production cost of the pyrogallol and has a good application prospect in the industrial production of the pyrogallol.

Description

[Technical field]

[0001] The invention belongs to the field of new materials of fine chemicals, uses tetrahalogen-substituted cyclohexanone as a raw material, and realizes efficient preparation of pyrogallol by a chemical synthesis method in an aqueous phase. The method can effectively reduce the production cost of pyrogallol and has good application prospects in its industrial production. [Background technology]

[0002] Pyrogallol, also known as 1,2,3-pyrogallol or commonly known as pyrogallol, is widely used as a photosensitizer in photoresist systems, an antioxidant for rubber materials, an extractant and collector for heavy metals or radioactive elements, a hair dye, a photographic developer, and an intermediate for fine chemicals and pesticides and medicines, and has broad application value.

[0003] Industrially, pyrogallol is usually prepared by high-temperature vacuum chemical decarboxylation reaction of gallic acid raw materials obtained from plant extracts such as gallnut, rhubarb, and tara powder. This method involves extraction, separation, and decarboxylation processes of natural products, has high requirements for production equipment, and has low yield. Literature reports that pyrogallol can also be prepared by heating and hydrolyzing tetrachlorocyclohexanone and sodium citrate aqueous solution (see CN 110437038 A), but this method requires the consumption of a large amount of sodium citrate, resulting in high costs and the generation of waste liquid and solid that are difficult to handle.

[0004] In view of the above problems, we designed a chemical preparation method for pyrogallol, that is, using tetrahalogen-substituted cyclohexanone as raw material, directly hydrolyzing it under high temperature and pressure in water to obtain pyrogallol and a dimer compound diphenyl ether tetraphenol with a new chemical structure. By adding different proportions of carboxylate additives to the reaction system, the ratio of the product pyrogallol and diphenyl ether tetraphenol dimer can be adjusted. The method is simple to operate, safe and efficient, low in cost, and easy to industrialize. [Summary of the invention]

[0005] The present application has unexpectedly discovered that, as shown in reaction formula (I), tetrahalogen-substituted cyclohexanone A can achieve the preparation of pyrogallol B and diphenyl ether tetraphenol dimer C under the following conditions.

[0006]

[0007] X in compound A is a halogen atom, i.e., one of F, Cl, Br, and I; the reaction conditions are at least one of solvent, temperature, additive, and pressure (or vacuum). Based on the total amount of products B and C as 100%, the yield of B is 0.1-99.9%, and the corresponding yield of C is 99.9%-0.1%.

[0008] The solvent is selected from at least one of water, substituted or unsubstituted aromatic hydrocarbons containing 1 to 24 carbon atoms, linear or branched aliphatic hydrocarbons, (sub)sulfones, amides, ethers, alcohols, esters, ketones, nitriles, carboxylic acids, amines, carbonates, ionic liquids, and supercritical carbon dioxide; or the substrate itself acts as a solvent medium at the same time.

[0009] In some preferred embodiments of the present invention, the solvent is selected from water, acetonitrile, methanol, ethanol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethyl sulfone, benzyl sulfoxide, benzyl sulfone, cyclobutylene sulfoxide, cyclobutylene, trichlorosilane, dichloromethane, chloroform, dichloroethane, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, chloroform, carbon tetrachloride, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetonitrile, ethylbenzene, diethylbenzene, chlorobenzene, dichlorobenzene , anisole, nitrobenzene, heptane, hexane, petroleum ether, dioxane, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, bis(ethylene glycol dimethyl ether), triethylene glycol dimethyl ether, propylene glycol methyl ether acetate, triethylamine, tributylamine, dimethyl isopropylamine, pyridine, N,N-tetramethylethylenediamine, N-alkylmorpholine, N-alkylpyrrole, N,N-dimethylformamide, formylmorpholine, N,N-diethylformamide and at least one of N-methylpyrrolidone. The solvent is preferably water or a mixed solvent of water and an organic solvent, and the mass ratio of the raw material compound A to the solvent is 1:1-1:1000, preferably 1:1-1:200.

[0010] The temperature is -70°C-400°C. Preferably, the temperature is -30°C-400°C. More preferably, the temperature is -20°C-300°C. The pressure is 0.001atm-200atm. Preferably, the pressure is 0.01atm-50atm.

[0011] The additives are reaction accelerators, synergists, catalysts, oxidants, polymerization inhibitors, reducing agents and / or functional additives. Based on the molar amount of the reaction raw material A, the additives are used in a catalytic amount or an equivalent amount or an over equivalent amount (0.001-1000 equivalents).

[0012] In the general formula (I), the additive or promoter in the reaction conditions is preferably a base; the base is a metal or its oxide, hydroxide, alkoxide, alkylamine, carbonate (bi) salt, carboxylate, sulfonate, organic amine, or nitrogen-containing heterocyclic compound. The preferred base is a metal carboxylate, carbonate (bi) salt, oxide, hydroxide, or alkoxide; the more preferred base is sodium acetate, potassium acetate, calcium acetate, zinc acetate, ammonium acetate, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, calcium oxide, and magnesium oxide.

[0013] In the general formula (I), the additive or promoter in the reaction conditions is preferably an acid; the acid is hydrochloric acid, sulfuric acid, nitric acid, a hydrohalic acid, a sulfonic acid, a carboxylic acid, a metal or its halide, a sulfide, an oxide, a carboxylate, a (hydrogen) sulfate, a nitrate, or a (hypo)halide. The preferred acid is hydrochloric acid, sulfuric acid, or a metal halide. The preferred metal halide is ferric chloride, zinc chloride, aluminum chloride, tin chloride, titanium chloride, copper chloride, or magnesium chloride.

[0014] This will be further explained in the examples. [Specific implementation method]

[0015] The gist of the present invention is further described below in conjunction with specific embodiments:

[0016] Embodiment 1:

[0017]

[0018] 2.36 g of tetrachlorocyclohexanone was weighed and added to 35 ml of water. The mixture was sealed and reacted at 160 degrees Celsius for about 6 hours. After cooling to room temperature and extraction with ethyl acetate, liquid chromatography was used to monitor that the tetrachlorocyclohexanone had completely reacted. The yields of pyrogallol and diphenyl ether tetraphenol dimer were 72% and 28%, respectively. The NMR data of the new compound diphenyl ether tetraphenol dimer are as follows: 1 H NMR (400MHz, DMSO-d6) δ9.77 (s, 1H), 9.12 (s, 1H), 6.81 (ddd, J = 13.0, 8.0, 1.6Hz, 2H), 6.72-6.63 (m, 1H). 13 C NMR (101MHz, DMSO-d6) δ147.20,142.34,120.71,120.33,119.91,114.49.

[0019] Embodiment 2:

[0020]

[0021] 2.36 g of tetrachlorocyclohexanone and 4.1 g of sodium acetate were weighed and added to 35 ml of water. The mixture was heated under reflux at 100 degrees Celsius for about 6 hours, cooled to room temperature, extracted with ethyl acetate, and liquid chromatography monitored that the tetrachlorocyclohexanone had been completely reacted. The yields of pyrogallol and diphenyl ether tetraphenol dimer were 95% and 5%, respectively.

[0022] It should be emphasized that the above embodiments are merely illustrative and not restrictive. Based on the disclosure of this application, any adjustment or change in reaction conditions or parameters that may be commonly adopted by practitioners will not deviate from the gist of the present invention. The scope of protection of this patent shall be based on the relevant rights record items.

Claims

1. A process for preparing pyrogallol, as shown in reaction formula (I), wherein pyrogallol B is obtained by reacting tetrahalocyclohexanone A under conditions, wherein diphenyl ether tetraphenol dimer C is simultaneously produced as a by-product: Wherein X is a halogen atom, i.e., one of F, Cl, Br, and I; and the reaction conditions are at least one of solvent, temperature, additive, and pressure (or vacuum). Taking the total amount of products B and C as 100%, The yield of B is 0.1-99.9%, and the corresponding yield of C is 99.9%-0.1%.

2. Chemical structure of the new substance diphenyl ether tetraphenol dimer C (Formula (II):

3. According to claim (1), the solvent is at least one of water, substituted or unsubstituted aromatic hydrocarbons, linear or branched aliphatic hydrocarbons, (sub)sulfones, amides, ethers, alcohols, esters, ketones, nitriles, carboxylic acids, amines, carbonates, ionic liquids, and supercritical carbon dioxide, or the substrate itself acts as a solvent medium. The temperature is -70°C-400°C. The pressure is 0.001atm-200atm. The additive refers to a reaction promoter, a synergist, a catalyst, an oxidant, an inhibitor, a reducing agent and / or a functional aid. Based on substrate A, the additive is used in an amount of 0.001-1000 equivalents.

4. According to claims (1 and 3), in the general formula (I), the additive or promoter in the reaction conditions is preferably a base; the base is a metal or its oxide, hydroxide, alkoxide, alkylamine, carbonate (bicarbonate), carboxylate, sulfonate, organic amine, or nitrogen-containing heterocyclic compound.

5. According to claims (1 and 3), in the general formula (I), the additive or promoter in the reaction conditions is preferably an acid; the acid is hydrochloric acid, sulfuric acid, nitric acid, a hydrohalic acid, a sulfonic acid, a carboxylic acid, a metal or its halide, sulfide, oxide, carboxylate, (hydrogen) sulfate, nitrate, (hypo)halate.

6. According to claims (1 and 2), the pyrogallol B and / or diphenyl ether tetraphenol dimer C prepared by the reaction of general formula (I) are used as photosensitizers in photoresist systems, antioxidants for rubber materials, heavy metal or radioactive element extractors and collectors, hair dyes, photographic developers, and precursor raw materials for the synthesis of pesticides and medicines.

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