TWI658033B - Process for preparing cyclohexanedimethanols and reaction precursors thereof - Google Patents

Abstract

The present invention relates to a process for the preparation of cyclohexanedimethanol and its reaction precursor comprising the compound of formula (II): Reaction with water in the presence of an organic solvent to form a compound of formula (III): The compound of the formula (III) can be further used as a raw material for the preparation of cyclohexanedimethanol.

Description

 Method for preparing cyclohexanedimethanol and its reaction precursor  

The invention relates to a process for preparing cyclohexanedimethanol and a reaction precursor thereof. More particularly, the present invention relates to a process for the preparation of benzenedimethanol and a process for the preparation of cyclohexanedimethanol using benzenedimethanol as the reaction precursor.

Conventionally, cyclohexanedimethanol is prepared by hydrogenating a compound containing an aromatic ring (for example, terephthalic acid or dimethyl terephthalate).

It is known in the art to carry out a one or two-step hydrogenation process under different catalyst conditions to give cyclohexanedimethanol. For example, using terephthalic acid as a raw material, in the hydrogenation process of two steps, the benzene ring is first hydrogenated to obtain 1,4-cyclohexanedicarboxylic acid, and then hydrogenated by a carboxyl group to obtain 1,4-cyclohexane. Dimethanol; patent documents exposing related processes are CN1915958A, CN105582927A, CN101982236B and CN104549251A. It is also possible to directly obtain 1,4-cyclohexanedimethanol by using a terephthalic acid as a raw material through a hydrogenation process in one step; and the patent documents exposing the related processes are CN100465145C and CN103877991B. There is also a hydrogenation process using dimethyl terephthalate via a single step to obtain 1,4-cyclohexanedimethanol; the related processes disclosed above are CN103028403B and CN105126832A.

In the above prior art, terephthalic acid or dimethyl terephthalate or the like is used as a raw material, and hydrogenation reaction must be carried out at a temperature of 200 ° C or higher, resulting in an increase in process cost and safety concerns, which is disadvantageous for mass production.

Another method for preparing cyclohexanedimethanol is to produce cyclohexanedimethanol by hydrogenation at a temperature of about 100 ° C using benzenedimethanol as a raw material, for example, as disclosed in the patent documents CN101096332A and CN103877998B. The method involves simple process, low temperature of hydrogenation reaction and low process cost. Therefore, it is a new research direction in the current technical field.

In view of this, the present invention provides a novel process for the preparation of benzenedimethanol. The process of the invention has simple steps and can even be prepared in a one-pot manner. Further, the obtained benzenedimethanol can be further used as a reaction raw material to prepare cyclohexanedimethanol, and as a whole, the cost of preparing cyclohexanedimethanol can be reduced.

It is an object of the present invention to provide a process for the preparation of a compound of formula (III), It comprises a compound of formula (II) The compound of formula (III) is formed by reaction with water in the presence of an organic solvent.

Another object of the present invention is to provide a process for the preparation of a compound of formula (III), It comprises the following steps: (a) making a compound of formula (I) (I)

Photooxidation in the presence of an oxidation system comprising at least one bromine compound to form a compound of formula (II) (b) reacting a compound of the formula (II) with water in the presence of an organic solvent B to form a compound of the formula (III).

Still another object of the present invention is to provide a process for further producing cyclohexanedimethanol from the above-obtained benzenedimethanol.

The process of the present invention is primarily a solid-liquid reaction and is therefore safer than other synthetic processes involving gas-liquid or gas-gas reactions. In addition, the present invention uses a simple reactant and reagent to prepare benzodiazepine, thereby avoiding the generation of complicated residues, and the reagent recovery process is relatively simple, and is not only more environmentally friendly but also more economical.

Further, in the process disclosed herein, the compound of formula (II) is reacted with water in the presence of a specific organic solvent to form a compound of formula (III). Compared with the method using only water as a reaction medium, the method of the present invention can increase the solubility of the reactant in the reaction phase by adding a specific organic solvent, in addition to eliminating the use of the phase transfer reagent. The reaction rate is increased and the reaction is carried out under high concentration conditions to achieve the advantages of higher batch mass production efficiency. Therefore, the method disclosed by the present invention can produce terephthalic acid more efficiently, which means that the production time can be reduced. Further, the organic solvent can be recovered by a simple method such as evaporation under reduced pressure, and the aqueous phase produced by the reaction can be further adjusted and reused as needed, thereby effectively utilizing the raw materials and reducing the production cost.

The compound of the formula (I) of the present invention is dimethylbenzene and comprises 1,2-dimethylbenzene, 1,3-dimethylbenzene and 1,4-dimethylbenzene, preferably 1,4- Dimethylbenzene.

The compound of the formula (II) disclosed in the present invention is bis(bromomethyl)benzene, which comprises 1,2-bis(bromomethyl)benzene, 1,3-di(bromomethyl)bromobenzene and 1,4-di (Bromomethyl)benzene, preferably 1,4-bis(bromomethyl)benzene.

The compound of the formula (III) disclosed in the present invention is benzenedimethanol, which comprises 1,2-benzenedimethanol, 1,3-benzenedimethanol and 1,4-benzenedimethanol, preferably 1,4-benzenedimethanol. .

Preparation of phenylmethanol

According to an embodiment of the present invention, the present invention provides a process for the preparation of a compound of formula (III), It comprises a compound of formula (II) The compound of formula (III) is formed by reaction with water in the presence of an organic solvent.

The organic solvent is an organic solvent which is not reactive with respect to the compound of the formula (II), and is selected from the group consisting of a ketone, an ether, a nitrile, an anthracene, a guanamine, and a combination thereof, and may be, for example, selected from the group consisting of acetone and methyl ethyl ketone. Diethyl ketone, methyl isobutyl ketone, cyclohexanone, diethyl ether, tetrahydrofuran (THF), 1,4-dioxane, diisopropyl ether, dibutyl ether, A Tert-butyl ether, acetonitrile, dimethyl hydrazine, diethyl hydrazine, N,N-dimethylformamide (DMF), N,N-diethylformamide, N,N- Dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), N-vinyl-2-pyrrolidone And the combination thereof is preferably selected from the group consisting of acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, 1,4-dioxane, acetonitrile, dimethyl hydrazine, diethyl hydrazine, N, N- Dimethylformamide (DMF), N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2- a group consisting of pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), N-vinyl-2-pyrrolidone, and combinations thereof, more preferably tetrahydrofuran (THF), 1,4- Dioxane (1,4-dioxane), acetonitrile or combinations thereof.

The weight ratio of the above organic solvent to water is between 1:10 and 10:1, preferably selected from the weight ratio of 1:10 to 1:1, and more preferably from 1 to weight ratio. : between 10 and 3:10.

In addition to the aforementioned organic solvents, the present invention may optionally contain other solvents, and may also contain organic solvents which are reactive with respect to the compound of formula (II), although this is a less desirable aspect, as long as it is present in an amount insufficient to (III) The compound could not be synthesized.

The weight ratio of the compound of the formula (II) to water is between 1:100 and 1:1, preferably selected from the range of 1:50 to 1:2 by weight, more preferably selected from the weight ratio. Between 1:10 and 1:5. Further, the preferred molar ratio of the compound of formula (II) to water is between 1:140 and 1:70.

In order to increase the rate of product formation and the yield of the desired product, and to reduce the formation of undesirable by-products, such as ether compounds, an alkaline reagent may be added to the above method for neutralization of the acidic substance produced in the reaction.

The aforementioned alkaline reagent is non-reactive, that is, it does not react with the reactant of the present invention, and may be selected from an organic base or an inorganic base, preferably an inorganic base.

The organic base to be used in the invention may, for example, be an alkylamine having an alkyl group having 1 to 6 carbon atoms, an alkanolamine having an alkyl group having 1 to 6 carbon atoms, or a basic amino acid. Specifically, examples of the alkylamine include methylamine, ethylamine, propylamine, butylamine, hexylamine, dimethylamine, and diethylamine. Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol, N-methyl-diethanolamine, and N,N-dimethyl Ethanolamine, aminomethylpropanol or the like is preferably at least one selected from the group consisting of triethanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol, and aminomethylpropanol. The basic amino acid may, for example, be an amino acid, a histidine or a arginine.

The inorganic base suitable for use in the present invention may be selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, barium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium carbonate, hydrogencarbonate. Potassium, calcium carbonate, calcium hydrogencarbonate, barium carbonate, magnesium carbonate, barium carbonate, barium carbonate and combinations thereof are preferably selected from the group consisting of sodium carbonate, sodium hydrogencarbonate, potassium carbonate, potassium hydrogencarbonate, calcium carbonate, and hydrogencarbonate. Calcium, barium carbonate, magnesium carbonate, barium carbonate, barium carbonate and combinations thereof, according to a preferred embodiment of the invention, the alkaline agent is sodium carbonate or potassium carbonate.

The amount of the aforementioned alkaline agent used is not particularly limited. According to an embodiment of the present invention, the ratio by weight of the compound of the formula (II) to the alkaline agent is between 10:1 and 1:10, preferably between 10:3 and 1:2, more preferably between Between 10:3 and 10:6.

The method of the present invention can increase the solubility of the reactants in the reaction phase by increasing the reaction rate by selecting a specific organic solvent, so that a relatively efficient reaction can be carried out even when the phase transfer catalyst is not used. In general, since phase transfer catalysts are expensive and it is often difficult to efficiently recycle the recoverable feedstock (including the phase transfer catalyst itself) after use, further advantages are provided without the use of a phase transfer catalyst. However, the method of the present invention may also add a phase transfer catalyst as needed. Examples of phase transfer catalysts are Crown ethers, Cryptand or quaternary ammonium salts, for example: [2.2.2] crypto-ether (crypt-222) ), 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 (Dibenzo-18-crown-6) and diazo-18-crown-6.

The method for preparing the compound of the formula (III) of the present invention, the compound of the formula (II) used can be purchased from a chemical supplier such as Haode Chemical Technology (Shanghai) Co., Ltd., Shanghai Maclean Biochemical Technology or the like.

According to another embodiment of the present invention, the method of the present invention for preparing a compound of formula (III) further comprises the steps of: firstly using a compound of formula (I) Photooxidation is carried out in the presence of an oxidation system comprising at least one bromine compound to form a compound of formula (II).

The process of this embodiment utilizes bromination of illumination (such as, but not limited to, UV light), and has the advantages of simple process, better safety of the solid-liquid reaction phase than the gas-liquid or gas-gase reaction. In addition, the present invention can utilize the compound of the formula (I) as a reaction raw material to produce a lower cost compound of the formula (II), and to prepare a compound of the formula (III), compared to a commercially available compound of the formula (II). Therefore, it has an economic advantage.

In particular, in this aspect, the invention provides a method of preparing a compound of formula (III), It comprises the following steps: (a) making a compound of formula (I)

Photooxidation in the presence of an oxidation system comprising at least one bromine compound to form a compound of formula (II) (b) reacting a compound of the formula (II) with water in the presence of an organic solvent B to form a compound of the formula (III).

In order to obtain a higher yield, step (c) may be further included as needed, after the step (b), the organic solvent C is added to extract the crude product of the compound of the formula (III). The above organic solvent C for extraction may be any suitable solvent, for example, the product (benzotrimethanol) has a good solubility, and has a low boiling point and is easily removed by evaporation. For example, a highly polar solvent is not limited to: ethyl acetate (EA), isobutyl acetate, n-butyl acetate.

In order to obtain a compound of the formula (III) having a higher purity (the purity of the product benzenedimethanol is more than 98.5%), the step (d) may be further included if necessary, by adding the organic solvent D to dissolve the step (b) or the step (c). The crude product is subjected to recrystallization purification. The organic solvent D may be a group consisting of methanol, ethanol, dichloromethane, dichloroethane, ethyl acetate, cyclohexane, and combinations thereof (for example, an equal ratio of ethyl acetate and cyclohexane solvent). .

The bromine compound contained in the oxidation system of the above step (a) is selected from the group consisting of Br ₂ , HBr, HOBr, M(Br) _k and combinations thereof, wherein the M system is selected from metal ions of an alkali metal or an alkaline earth metal. k is equal to the valence of M.

In addition to the aforementioned bromine compound, the oxidation system of the above step (a) may further comprise one or more of the following compounds: a peroxide such as, but not limited to, hydrogen peroxide (H ₂ O ₂ ), sodium peroxide (Na ₂ O ₂ ) , potassium peroxide (K ₂ O ₂ ), calcium peroxide (CaO ₂ ), magnesium peroxide (MgO ₂ ), zinc peroxide (ZnO ₂ ), strontium peroxide (SrO ₂ ), organic peroxide or a combination thereof Non-brominated halogens such as Cl ₂ ; bromine-free hydrohalic acids such as hydrofluoric acid, hydrochloric acid, hydroiodic acid; hypohalites such as hypofluorite, hypochlorite, hypobromous acid Salts, hypoiodates, further exemplified by NaOCl, NaOBr, NaOI, KOCl, KOBr, KOI; bromo halide-free salts, such as NaCl, KI, NaI, KCl; acids, which may be selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid , acetic acid and combinations thereof.

Specifically, the oxidation system of the above step (a) may be selected from a bromine compound, a bromine compound / H ₂ O ₂ , a bromine compound / Cl ₂ , a bromine compound / a hydrohalic acid, a bromine compound / a hypohalite, a bromine compound / Acid / H ₂ O ₂ , bromine compound / acid / halide salt. Preferred oxidation systems may be selected from the group consisting of Br ₂ , Br ₂ /H ₂ O ₂ , HBr/H ₂ O ₂ , HBr/Cl ₂ , bromine compounds/acids/H ₂ O ₂ , HBr/bromo-free hydrohalic acids, HBr/HOBr, bromine compound/acid/halogenated acid salt, bromine compound/acid/bromo-free halide salt and HBr/HOBr/acid. According to a preferred embodiment of the invention, the oxidation system is a chlorine-free oxidation system, preferably Br ₂ /H ₂ O ₂ , HBr/H ₂ O ₂ , HBr/sulfuric acid/H ₂ O ₂ or NaBr. / sulfuric acid / H ₂ O ₂ .

According to an embodiment of the present invention, the above step (a) can be carried out in the presence of an organic solvent A, and the organic solvent A used in the step (a) can be a non-polar solvent (such as cyclohexane) or a halogenated hydrocarbon (such as dichloro). Methane (DCM) or dichloroethane (DCE), preferably dichloroethane (DCE).

The type of organic solvent B involved in step (b), the ratio of organic solvent B to water, and the ratio of the compound of formula (II) to water are as described herein before.

The non-reactive basic substance can be selectively added in the above step (b) as a neutralizing agent, which is more advantageous for the progress of the reaction. The non-reactive basic material is as described herein before.

In the above step (b), a phase transfer catalyst may be optionally added, the phase transfer catalyst being as described herein before. Preferably, no phase transfer catalyst is used.

The process for preparing the compound of the formula (III) of the present invention can be carried out in a one-pot process or in a stepwise process. Stepwise methods are commonly used in synthetic methods, and those having ordinary skill in the art can select an appropriate purification step after each synthesis step to obtain higher yield intermediates and final products. On the other hand, the one-pot method is simpler and more economical. In a preferred embodiment of the present invention, a one-pot method is used, and it is shown in the specific examples that a potting method according to the present invention may also achieve a better yield than the stepwise method or equivalent thereto.

Hereinafter, an embodiment of the potting method and the stepwise synthesis of the compound of the formula (III) of the present invention will be further described by taking the synthesis of 1,4-benzenedimethanol as an example, but the invention is not limited thereto.

One-pot method

According to the present invention, the compound of the formula (I) (for example, 1,4-dimethylbenzene) can be converted into the compound of the formula (III) (1,4-benzenedimethanol) by a one-pot method, and the specific steps are as follows: (1) dissolving 1,4-dimethylbenzene in an organic solvent 1 (for example, dichloroethane) in which an oxidation system (oxidant 1 (for example, hydrobromic acid) and oxidant 2 (for example, concentrated sulfuric acid)) is present) DCE) to form a mixture; (2) a peroxide (for example, H ₂ O ₂ ) is added to the mixture of the step (1) by titration, and photooxidation is carried out, and formation is observed after the photooxidation reaction. The organic layer, the aqueous layer and the solid product, the solid product is mostly precipitated and partially soluble in the organic layer; (3) the organic solvent 1 is removed (for example, by evaporation under reduced pressure), and then left to stand, and then the remaining portion is removed. The aqueous layer is then added with an organic solvent 2 (for example, dioxane, dioxane) and water, preferably with a non-reactive basic substance (such as sodium carbonate), and heated to 25 ° C to 100 ° C (for example, 80 ° C) After 0.5 to 100 hours (for example, 5 hours), removing the organic solvent 2 (for example, by evaporation under reduced pressure, etc.), a crude product of p-benzodimethanol can be obtained; (4) After extraction with an organic solvent 3 (for example, ethyl acetate, EA), the organic solvent is removed by evaporation to obtain a crude product of p-benzodimethanol; (5) the crude product is an organic solvent 4 (for example, ethyl acetate or cyclohexane). The alkane is subjected to recrystallization, and the p-benzodimethanol refined product is obtained by filtration and drying.

The organic solvent 1 involved in the above steps (1) and (3) is an organic solvent A as described in the above step (a), and the organic solvent 2 is not reactive with respect to the compound of the formula (II) as described herein. Organic solvent B, the oxidation system is as previously described herein.

The type and amount of the non-reactive basic substance in the above step (3) are also as described above. The reaction temperature of the above step (3) is preferably such that it can be heated to the system to produce reflux. Therefore, the corresponding heating temperature can be adjusted according to the choice of solvent.

The reaction time in the above step (3) is preferably from 1 to 20 hours after heating to the reaction temperature, and the water and the organic solvent 2 can be removed by adjusting the parameters of the reduced pressure evaporation method to the extent that extraction is facilitated. For example, it is preferred that the amount of water removed is one-half or less of the amount, and the amount of the organic solvent removed is one-half or more of the amount, so that the product remains dissolved and can be subsequently extracted. The step is exchanged to the organic solvent for extraction.

The organic solvent 3 involved in the above step (4) is an organic solvent C as referred to in the step (c) previously described herein. The aqueous phase waste liquid produced after the extraction can be further adjusted and recovered as needed and can be reused.

The organic solvent 4 involved in the above step (5) is an organic solvent D as referred to in the step (d) previously described herein. The above step (5) can also be selectively carried out under heating to promote dissolution of the crude product in the organic solvent 4. Preferably, the purity of the product benzenedimethanol is 98.5% or more after the recrystallization step, and the purity of the reaction by-product is 1% or less, preferably 0.5% or less. The above by-product contains an ether compound, for example, to prepare 1,4-benzenedimethanol, and the obtained by-product comprises the compound of the formula (V):

Stepwise method

According to the present invention, a stepwise method for synthesizing a compound of formula (III) comprising a first step (B-1) and a second step (B-2), wherein the first step (B-1) is a formula (I) The compound (for example, 1,4-dimethylbenzene) is converted into a compound of the formula (II) (for example, 1,4-bis(bromomethyl)benzene), and then the second step (B-2) is a formula (II) Conversion of the compound to a compound of the formula (III) (for example, 1,4-benzenedimethanol).

The specific steps of B-1 in the above route are as follows: (1-1) Dissolving 1,4-dimethylbenzene in which organic solvent 1 (for example, DCE) and an oxidation system (oxidant 1 (for example, hydrobromic acid) are present) In a mixture with an oxidizing agent 2 (for example, concentrated sulfuric acid); (1-2) a peroxide (for example, H ₂ O ₂ ) is added in a titrated manner to the mixture of the step (1-1), and light is carried out. In the oxidation reaction, an organic layer, an aqueous layer and a solid product are observed after the photooxidation reaction, and most of the solid product precipitates and a small portion is soluble in the organic layer; (1-3) the organic solvent 1 is removed (for example) After treatment by evaporation under reduced pressure or heating, etc., after treatment with solvent 5 (for example, methanol or ethanol) (for example, washing and filtration), high purity 1,4-bis(bromomethyl)benzene is obtained. The specific steps of B-2 in the above route are as follows: (2-1) 1,4-bis(bromomethyl)benzene with water and a selective non-reactive basic substance (such as sodium carbonate) and an organic solvent 2 Mixing (for example, dioxane), reacting at a suitable temperature for a certain period of time (for example, in the case of dioxane, it can be reacted at a temperature of, for example, about 80 ° C for about 3 to 5 hours), removing part of water and organic solvent 2 ( For example, crude product of p-benzodimethanol can be obtained by evaporation under reduced pressure; (2-2) extraction can be carried out using organic solvent 3 (for example, EA), and organic solvent 3 can be removed to obtain a higher yield of p-benzoic acid. The crude product of methanol; (2-3) the crude product is recrystallized using an organic solvent 4 (for example, ethyl acetate and cyclohexane), and the p-benzodimethanol refined product is obtained by filtration and drying.

The organic solvents 1 to 4 involved in the above respective steps are the organic solvents 1 to 4 as referred to in the one-pot method described herein before, and the oxidation system is as described herein before.

The solvent 5 to be treated in the above step (1-3) may be any suitable solvent such as, but not limited to, methanol or ethanol.

The phase transfer catalyst may be selectively added in the above step (2-1), and the type of the phase transfer catalyst is as described herein before; preferably, no phase transfer catalyst is added.

The aqueous phase waste liquid produced after the above step (2-2) is extracted may be further adjusted and reused as needed.

The recrystallization step involved in the above step (2-3) can also be carried out selectively under heating.

Preparation of cyclohexanedimethanol (CHDM) from benzenedimethanol

The benzenedimethanol (i.e., the compound of the formula (III)) obtained by the above method can be used as a precursor for the synthesis of cyclohexanedimethanol.

The invention also provides a process for the preparation of cyclohexanedimethanol (i.e., a compound of formula (IV)) from a compound of formula (III),

It is a hydrogenation reaction of a compound of the formula (III) prepared by the aforementioned method in the presence of a hydrogen source to form the compound of the formula (IV).

The hydrogenation reaction conditions are preferably carried out under high pressure hydrogen at 100 °C.

The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention. Modifications and variations that may be readily made by those skilled in the art are included within the scope of the disclosure of the present disclosure and the scope of the appended claims.

Example

Purity determination: Product purity was analyzed using a gas chromatograph (GC: Model Agilent 6890).

Preparation of precursors of compounds of formula (IV) Example 1: Preparation of p-phenylenediethanol by one-pot method

74 g (0.7 mol) of p-xylene, 242 g (1.44 mol) of hydrobromic acid and 7 g of concentrated acid were dissolved in 300 g of DCE, and 119 g of 50% hydrogen peroxide (1.75 mol) was slowly dried in an ice bath. It is added to the above reactants, and the reaction temperature in the titration process is controlled to be 5 ° C or less while being irradiated with a visible light lamp (wavelength of about 400 nm). The irradiation process formed about 12 hours to form a crude product. After removing DCE by vacuum evaporation, the remaining aqueous layer was removed, and 1500 g of water, 60 g of sodium carbonate and 450 g of 1,4-dioxane were added, and the temperature was raised to 80 ° C for 3 hours. After concentrating under reduced pressure to remove 1,4-dioxane and a portion of water, ethyl acetate (300 g x 2 times) was added for extraction, and then 200 g of cyclohexane was added to the organic solvent layer, followed by recrystallization, filtration and drying to obtain 67 g. High purity product of p-phenylenediethanol (yield 70%, purity 99.2%). The finished product contained only 0.46% of the compound of formula (V).

Example 2: Synthesis of 1,4-bis(bromomethyl)benzene

119 g of 50% hydrogen peroxide (1.75 mol) was slowly added in an ice bath to 74 g (0.7 mol) of 1,4-xylene, 242 g (1.44 mol) of hydrobromic acid and 7 g of concentrated sulfuric acid in 300 g of DCE. The mixture was then irradiated by a visible light lamp (wavelength of about 400 nm) for 12 hours to form an organic layer (DCE), a precipitated crude product and an aqueous phase layer, and a crude product was partially present in the organic layer. After removing DCE from the crude product by evaporation under reduced pressure, 30 g of methanol was added and stirred at 60 ° C for one hour, then cooled to room temperature, and filtered to obtain 150 g of 1,4-bis(bromomethyl)benzene. Purity finished product (yield 80%, purity 98.2%).

Example 3: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of 1,4-dioxane were mixed, and the mixture was heated to 80 ° C for about 3 hours, and added to an aqueous solution of sodium carbonate. And to weakly alkaline, most of the solvent of the organic layer is removed via a cyclotron. The crude product was extracted with ethyl acetate (400 g x 2 times), and the organic layer was removed from the solvent by a rotary concentrator to obtain 47 g of crude product of terephthalic acid. The crude p-benzenediethanol product was recrystallized using ethyl acetate and cyclohexane to obtain 42 g of a high purity product of terephthalic acid (yield 80.0%, purity 99.3%).

Example 4: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of THF were mixed, and the mixture was heated to reflux for about 22 hours, and neutralized by adding an aqueous sodium carbonate solution to weakly alkaline. The cyclone concentrator removes most of the solvent. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to obtain 37 g of a high purity product of terephthalic acid (yield 70.5%, purity 99.3%).

Example 5: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of methyl ethyl ketone are mixed, and the mixture is heated to reflux for about 18 hours, and neutralized to a weak alkalinity by adding an aqueous sodium carbonate solution. Most of the solvent is removed via a cyclone concentrator. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to obtain 38 g of a high purity product of terephthalic acid (yield 72.4%, purity 99.1%).

Example 6: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of NEP were mixed, and the mixture was heated to reflux for about 3 hours, and neutralized by adding an aqueous solution of sodium carbonate to weakly alkaline. The cyclone concentrator removes most of the solvent and extracts the crude product using ethyl acetate (400 g x 2 times). The solvent of the organic layer is removed by a cyclone concentrator to obtain 247 g of crude product, which contains NEP and 14% of the crude product. The yield of benzenedimethanol and p-phenylenediethanol was 69%.

Example 7: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of DMF were mixed, and the temperature was raised to reflux for about 3 hours, and neutralized by adding an aqueous sodium carbonate solution to weakly alkaline. The cyclone concentrator and oil pump remove DMF and water. The crude product was extracted with water (400 g) and ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 44 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to give 35 g of a high purity product of terephthalic acid (yield 67%, purity 98.8%).

Example 8: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of DMSO were mixed, and the mixture was heated to reflux for about 3 hours, and neutralized by adding an aqueous solution of sodium carbonate to weakly alkaline. The cyclone concentrator removes most of the solvent. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed by a cyclone concentrator to obtain 268 g of a crude product containing DMSO and 13% of terephthalic acid and terephthalic acid. The yield was 67%.

Example 9: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of acetonitrile were mixed, and the temperature was raised to 80 degrees for about 3 hours, and neutralized by adding an aqueous solution of sodium carbonate to weakly alkaline. Most of the solvent is removed via a cyclone concentrator. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 47 g of crude product. The crude product was crystallized from ethyl acetate and cyclohexane to obtain 38 g of a high purity product of terephthalic acid (yield: 72.4%, purity: 99%).

Example 10: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 1 g of 18-crown-6, 60 g of sodium carbonate, 1000 g of soft water and 100 g of THF were mixed, and the mixture was heated to reflux for 18 hours, and removed by a cyclone concentrator. Most solvents. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to give 37.8 g of terephthalic acid (yield: 72%, purity: 99.1%).

Example 11: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 1 g of 18-crown-6, 30 g of sodium carbonate, 1000 g of soft water and 300 g of THF were mixed, and the mixture was heated to reflux for about 20 hours, and added to an aqueous solution of sodium carbonate. And to weakly alkaline, most of the solvent is removed via a cyclotron. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to obtain 36.8 g of terephthalic acid (yield 70%, purity: 99.3%).

Comparative Example 1: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate and 1300 g of soft water are mixed, heated to reflux for about 18 hours, neutralized by adding sodium carbonate aqueous solution to weakly alkaline, and passed through a cyclone concentrator. Remove most of the water. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to give 32.8 g of terephthalic acid (yield 62.5%, purity 99.1%).

Comparative Example 2: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of ethanol were mixed, and the mixture was heated to reflux for about 3 hours, and neutralized by adding an aqueous solution of sodium carbonate to weakly alkaline. The cyclone concentrator removes most of the solvent. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to give 21 g of terephthalic acid (yield 40%, purity 98.5%).

Comparative Example 3: Synthesis of p-phenylenediethanol

100 g (0.38 mol) of 1,4-bis(bromomethyl)benzene, 30 g of sodium carbonate, 1000 g of soft water and 300 g of isopropanol were mixed, and the mixture was heated to reflux for about 8 hours, and neutralized to a weakly alkaline state by adding an aqueous sodium carbonate solution. Most of the solvent was removed via a cyclone concentrator. The crude product was extracted with ethyl acetate (400 g x 2 times), and the solvent of the organic layer was removed via a rotary concentrator to obtain 45 g of crude product. The crude product was recrystallized from ethyl acetate and cyclohexane to give 31 g of terephthalic acid (yield: 59%, purity 98.7%).

Claims (11)

A method of preparing a compound of formula (III), It comprises a compound of formula (II) The compound of the formula (III) is formed by reacting with an organic solvent in the presence of a non-reactive basic substance, wherein the organic solvent is selected from the group consisting of a ketone, an ether, a nitrile, an anthracene, a guanamine, and a combination thereof. . The method of claim 1, wherein the compound of formula (II) is And the compound of formula (III) is . The method of claim 1, wherein the organic solvent is selected from the group consisting of acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, diethyl ether, tetrahydrofuran, 1,4-dioxane, diisopropyl Ether, dibutyl ether, methyl tert-butyl ether, acetonitrile, dimethyl hydrazine, diethyl hydrazine, N,N-dimethylformamide, N,N-diethylformamide , N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone and A group of its combination. The method of claim 1, wherein the weight ratio of the organic solvent to water is from 1:10 to 10:1. The method of claim 1, wherein the weight ratio of the compound of formula (II) to water is 1:100 to 1:1. The method of claim 1, further comprising the step of: rendering a compound of formula (I) Photooxidation in the presence of an oxidation system comprising at least one bromine compound to form a compound of formula (II) The method of claim 6, wherein the bromine compound is selected from the group consisting of Br ₂ , HBr, HOBr, and M(Br) _{k ,} and combinations thereof, wherein the M system is selected from the group consisting of alkali metal or alkaline earth metal ions, and k is equal to the valence of M. The method of claim 6 wherein the oxidizing system further comprises one or more of the following compounds: a peroxide, a non-bromine halogen, a bromine-free hydrohalic acid, a hypohalite, a bromine-free halide salt, an acid . The method of claim 8, wherein the oxidation system is selected from the group consisting of: Br ₂ , Br ₂ /H ₂ O ₂ , HBr/H ₂ O ₂ , HBr/Cl ₂ , bromine compound/acid/H ₂ O ₂ , HBr/ a bromine-free hydrohalic acid, HBr/HOBr, a bromine compound/acid/halogenated acid salt, a bromine compound/acid/bromo-free halide salt, and an HBr/HOBr/acid, wherein the acid is selected from the group consisting of sulfuric acid and nitric acid. And phosphoric acid, acetic acid and combinations thereof, the bromine-free hydrohalic acid is selected from the group consisting of hydrofluoric acid, hydrochloric acid, hydroiodic acid and combinations thereof, and the bromine-free halide salt is selected from NaCl. a group consisting of KI, NaI, KCl, and combinations thereof, the hypohalite salt being selected from the group consisting of NaOCl, NaOBr, NaOI, KOCl, KOBr, KOI, and combinations thereof. The method of claim 8, wherein the oxidation system is selected from the group consisting of Br ₂ /H ₂ O ₂ , HBr/H ₂ O ₂ , NaBr/sulfuric acid/H ₂ O ₂ and HBr/sulfuric acid/H ₂ O ₂ . A method of preparing a compound of formula (IV), It comprises the preparation of a compound of formula (III) by the method of any one of claims 1 to 10, and hydrogenation of the compound of formula (III) in the presence of a hydrogen source to form the compound of formula (IV).