A method for synthesizing copper porphyrin from aromatic aldehyde, pyrrole and copper salt

Abstract

The invention discloses a method for synthesizing copper porphyrin from aromatic aldehyde, pyrrole and copper salt. Under the catalysis of anhydrous aluminum chloride, aromatic aldehyde, pyrrole and copper salt are refluxed in DMF solvent to generate tetraaryl copper porphyrin through a one-pot reaction. The reaction process is: anhydrous aluminum chloride, aromatic aldehyde, pyrrole and copper salt are sequentially added to DMF under stirring, the reaction is stopped after heating and refluxing for a certain period of time, the temperature is lowered, the mixture is placed at about 273K overnight, and copper porphyrin crystals are obtained by suction filtration. The method directly uses aromatic aldehyde, pyrrole and copper salt as raw materials, does not need to use porphyrin, does not use highly corrosive organic acid as solvent, obtains high-purity tetraaryl copper porphyrin with high yield without using complex separation means, and is easy to realize industrial production.

Description

Technical Field

[0001] The invention relates to a method for synthesizing tetraaryl copper porphyrin, in particular to a method for synthesizing tetraaryl copper porphyrin in one pot by using aromatic aldehyde, pyrrole and copper salt as raw materials and anhydrous aluminum chloride as catalyst in DMF solvent, belonging to the field of organic synthesis. Background Art

[0002] Copper porphyrin is a metal organic compound with a macrocyclic conjugated structure. The ligand porphin of copper porphyrin is a large cyclic molecule composed of 20 carbon atoms and 4 nitrogen atoms, with a stable conjugated system of 4n+2 electrons and aromaticity. In industrial production and life, copper porphyrin is mainly used as a catalyst for chemical oxidation and electrical and photooxidation. The copper porphyrin commonly used as a catalyst is tetraaryl copper porphyrin. The chemical synthesis method of tetraaryl copper porphyrin reported in the literature and patents is generally based on the basic reaction of tetraaryl porphyrin as raw material and copper salt reported by Adler et al. (J. Inorg. Nucl. Chem., 1970, 32, 2443). The chemical process involved is:

[0003]

[0004] During the reaction, divalent copper ions coordinate with tetraarylporphine to form stable divalent copper porphyrin. Patent CN103880851B discloses a method for producing copper porphyrin on an industrial scale by reacting the above-mentioned tetraarylporphine as a raw material with a copper salt through a continuous process. The biggest disadvantage of this reaction is that the raw material tetraarylporphine used in the synthesis of copper porphyrin is expensive, and in a neutral or slightly alkaline environment, the instability of copper porphyrin is prone to copper ion shedding, which affects the purity of the divalent copper porphyrin product.

[0005] From the existing literature, there are also reports on the one-pot synthesis of zinc porphyrin using aromatic aldehydes, pyrrole and zinc salts as raw materials. Badger et al. reported the one-step synthesis of zinc porphyrin using aromatic aldehydes, pyrrole and zinc salts as raw materials in an autoclave (Australian J Chem, 1964, 19, 1028).

[0006]

[0007] However, this reaction condition cannot be used to prepare copper porphyrin. In propionic acid solvent, copper salt cannot react with porphyrin to form copper porphyrin with poor stability.

[0008] In view of the fact that zinc porphyrin can be replaced with copper salt to obtain copper porphyrin (Chemical Technology, 2000, 8, 1; Journal of Shenyang University of Technology, 2010, 60; Chemical Research and Application, 2012, 24, 154), patent CN1238355C discloses a reaction in which a mixture of zinc porphyrin and porphine is obtained by using aromatic aldehyde, pyrrole and zinc salt as raw materials without using an autoclave, and then the mixture of zinc porphyrin and porphine is reacted with copper acetate to synthesize copper porphyrin.

[0009]

[0010] In the above process, the intermediate products porphyrin zinc and porphine need to be obtained through a separation process, and the propionic acid solvent used in the first step is an organic acid with strong corrosiveness. In addition, if copper salt is directly added to the propionic acid system, divalent copper ions cannot coordinate with porphine to obtain copper porphyrin. Summary of the invention

[0011] In view of the defect that the prior art cannot synthesize tetraaryl copper porphyrin from aromatic aldehyde, pyrrole and copper salt in one pot and needs to synthesize tetraaryl copper porphyrin from expensive metalation reaction of tetraaryl porphyrin and copper salt or from expensive metal replacement reaction of tetraaryl zinc porphyrin and copper salt, the purpose of the present invention is to provide a method for synthesizing tetraaryl copper porphyrin from basic organic raw materials aromatic aldehyde, pyrrole and copper salt in one pot, and obtaining high-purity tetraaryl copper porphyrin in high yield without using complicated separation means, and the method is easy to realize industrial production.

[0012] The reaction raw materials used to realize the present invention are simple organic raw materials, aromatic aldehyde and pyrrole, and inorganic copper salt, the reaction solvent is DMF, and the catalyst is a non-protonic inorganic acid, anhydrous aluminum chloride.

[0013] The chemical reaction on which the present invention is based is as follows:

[0014]

[0015] The aromatic group Ar can be a benzene ring or an aromatic heterocycle such as pyridine, pyrrole, furan, naphthalene, quinoline, etc.;

[0016] The substituent R on the aryl group Ar may be an alkyl substituent such as methyl, ethyl, propyl or a halogen substituent such as chlorine, bromine or iodine, or an oxygen-containing substituent such as methoxy, ethoxy, hydroxyl or carboxyl or a nitrogen-containing substituent such as amino, dimethylamino or nitro;

[0017] The copper salt used in the reaction can be copper acetate, copper chloride, copper bromide, copper nitrate, or copper sulfate.

[0018] The operation process of the present invention is as follows: DMF is added to a commonly used reflux stirring reactor and added until boiling, anhydrous aluminum chloride, aromatic aldehyde, pyrrole and copper salt are added in sequence under stirring, the reaction is stopped after a certain reaction time, the temperature is lowered, the reaction is placed at about 273K overnight, and copper porphyrin crystals are obtained by suction filtration.

[0019] The input ratio (molar ratio) of aromatic aldehyde, pyrrole, copper salt and anhydrous AlCl3 is: 1-1.5:1-1.5:1-5:1-5, and the preferred ratio is 1:1:3:1.5;

[0020] The molar ratio of pyrrole to DMF is 1:500-1500, preferably 1:800;

[0021] The reaction time is 0.5-3 hours, preferably 1 hour.

[0022] The reaction requires that all reactants are added at room temperature and then heated to reflux. If reactants are added after reflux, or copper salt is added after reflux, the desired product cannot be obtained or the product yield is reduced.

[0023] According to the technical scheme of the present invention, the condensation of aromatic aldehyde and pyrrole and the metallization of the condensation product and divalent copper ions occur simultaneously, so that the two-step reaction of the prior art of synthesizing tetraaryl copper porphyrin with aromatic aldehyde and pyrrole as raw materials is changed into a one-step reaction. Meanwhile, the divalent copper ions also play a template role in the condensation process of aromatic aldehyde and pyrrole to improve the condensation yield; non-protonic acid anhydrous AlCl3 is used as an acidic catalyst, which can not only promote the condensation of aromatic aldehyde and pyrrole, but also accelerate the metallization reaction of porphyrin and copper ions and reduce the shedding of copper ions in copper porphyrin; the use of DMF as a solvent can dissolve anhydrous AlCl3, which is conducive to exerting the catalytic performance of AlCl3 on the condensation of aromatic aldehyde and pyrrole, and the difference in the solubility of DMF on organic hydrocarbon substances and metal compounds makes the tetraaryl copper porphyrin crystallize and precipitate at low temperature, and various intermediate impurities formed by the condensation of aromatic aldehyde and pyrrole in the reaction process will not be precipitated with the product, so that the product tetraaryl copper porphyrin is easy to separate.

[0024] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0025] 1) Compared with the prior art of synthesizing copper porphyrin using porphyrin as raw material, the raw materials aromatic aldehyde and pyrrole used in the present invention are more economical and readily available than porphyrin, and can effectively avoid the shedding of copper ions in the product copper porphyrin to reduce by-products, improve product purity, and simplify the separation process;

[0026] 2) Compared with the prior art of synthesizing tetraaryl copper porphyrin using aromatic aldehyde and pyrrole as raw materials, the present invention only requires one step of reaction, does not require the use of special equipment, reduces the reaction steps, and the product yield under optimal conditions can reach up to 53%. At the same time, it can also avoid the large-scale use of corrosive organic acids, and has good environmental benefits.

[0027] 3) The technical solution of the present invention has simple steps and strong operability, and meets the requirements of industrial production. Example

[0028] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the claims. The raw materials involved in the examples are all commercially available conventional raw materials unless otherwise specified.

[0029] Embodiment 1:

[0030] 400 mL of DMF was added to a stirred reactor equipped with a reflux condenser, and 0.75 mol of anhydrous aluminum chloride, 0.5 mol of benzaldehyde, 0.5 mol of pyrrole and 1.5 mol of copper acetate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 1 hour before stopping the reaction, cooling, and leaving at 273 K overnight. Purple-red crystals of tetraphenylcopper porphyrin were obtained by suction filtration with a yield of 53%.

[0031] Embodiment 2:

[0032] 1800 mL of DMF was added to a stirred reactor equipped with a reflux condenser, and 1 mol of anhydrous aluminum chloride, 0.8 mol of 3-bromopyridinecarboxaldehyde, 0.6 mol of pyrrole and 1.5 mol of cupric chloride were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 1.3 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetra(3-bromopyridine)copperporphyrin were obtained by suction filtration with a yield of 45%.

[0033] Embodiment three:

[0034] 2800 mL of DMF was added to a stirred reactor with a reflux condenser, and 1.2 mol of anhydrous aluminum chloride, 0.8 mol of 2-ethylpyrrole carboxaldehyde, 0.7 mol of pyrrole and 2 mol of copper bromide were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 2 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetra(2-ethylpyrrole)copperporphyrin were obtained by suction filtration with a yield of 40%.

[0035] Embodiment 4:

[0036] 1500 mL of DMF was added to a stirred reactor with a reflux condenser, and 0.75 mol of anhydrous aluminum chloride, 0.75 mol of 5-hydroxy-1-naphthaldehyde, 0.75 mol of pyrrole and 2 mol of copper nitrate were added in sequence under stirring. The reaction mixture was heated to reflux and the reaction was maintained for 1.8 hours before stopping the reaction, cooling, and leaving at 273 K overnight. Tetrakis(5-hydroxy-1-naphthylpyridine)copperporphyrin was obtained by suction filtration with a yield of 35%.

[0037] Embodiment five:

[0038] 1000 mL of DMF was added to a stirred reactor with a reflux condenser, and 1 mol of anhydrous aluminum chloride, 0.6 mol of 3-methylfurfural, 0.5 mol of pyrrole and 1.8 mol of copper sulfate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 1.8 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetra(3-methylfuran)copperporphyrin were obtained by suction filtration with a yield of 37%.

[0039] Embodiment six:

[0040] 1500 mL of DMF was added to a stirred reactor with a reflux condenser, and 0.5 mol of anhydrous aluminum chloride, 0.7 mol of 5-methoxy-2-quinolinecarboxaldehyde, 0.5 mol of pyrrole and 1.2 mol of copper acetate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 3 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetrakis(5-methoxy-2-quinoline)copperporphyrin were obtained by suction filtration with a yield of 32%.

[0041] Embodiment seven:

[0042] 2500 mL of DMF was added to a stirred reactor equipped with a reflux condenser, and 2 mol of anhydrous aluminum chloride, 0.75 mol of 4-chlorobenzaldehyde, 0.5 mol of pyrrole and 2 mol of copper acetate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 2.5 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetrakis(4-chlorophenyl)copperporphyrin were obtained by suction filtration with a yield of 48%.

[0043] Embodiment eight:

[0044] 2000 mL of DMF was added to a stirred reactor with a reflux condenser, and 2.5 mol of anhydrous aluminum chloride, 0.5 mol of 3-aminobenzaldehyde, 0.5 mol of pyrrole and 1.5 mol of copper acetate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 2 hours, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Blue crystals of tetrakis(3-aminophenyl)copperporphyrin were obtained by suction filtration with a yield of 28%.

[0045] Embodiment nine:

[0046] 2000 mL of DMF was added to a stirred reactor with a reflux condenser, and 2 mol of anhydrous aluminum chloride, 0.6 mol of 4-carboxybenzaldehyde, 0.5 mol of pyrrole and 2.2 mol of cupric acetate were added in sequence under stirring. The reaction mixture was heated to reflux and the reaction was maintained for 0.8 hours before stopping the reaction, cooling, and leaving at 273 K overnight. Purple-red crystals of tetrakis(4-carboxyphenyl)copperporphyrin were obtained by suction filtration with a yield of 18%.

[0047] Embodiment ten:

[0048] 1500 mL of DMF was added to a stirred reactor with a reflux condenser, and 0.8 mol of anhydrous aluminum chloride, 0.6 mol of 4-nitrobenzaldehyde, 0.5 mol of pyrrole and 2.5 mol of copper acetate were added in sequence under stirring. The reaction mixture was heated to reflux and maintained for 0.5 hour, then the reaction was stopped, the temperature was lowered, and the mixture was placed at 273 K overnight. Purple-red crystals of tetrakis(4-nitrophenyl)copperporphyrin were obtained by suction filtration with a yield of 23%.

Claims

1. A method for synthesizing copper porphyrin from aromatic aldehydes, pyrrole and copper salts, characterized in that: Aromatic aldehyde, pyrrole and copper salt are used as raw materials, and anhydrous aluminum chloride is used as a catalyst in DMF solvent to synthesize tetraaryl copper porphyrin in one pot; the reaction process is: DMF is added to a reflux stirring reactor at room temperature, stirring is started, and anhydrous aluminum chloride, aromatic aldehyde, pyrrole and copper salt are added in sequence; the reaction mixture is heated to reflux, and the reaction is stopped after a certain period of time, the temperature is lowered, and the reaction is placed at about 273K overnight, and copper porphyrin crystals are obtained by suction filtration. The structure of the aromatic aldehyde is as follows: ； The tetraaryl copper porphyrin has the following structure: ； Ar is a phenyl ring group, a pyridyl group, a pyrrolyl group, a furyl group, a naphthyl group or a quinolyl group; The substituent R on Ar is methyl, ethyl, propyl, chlorine, bromine, iodine, methoxy, ethoxy, hydroxy, carboxyl, amino, dimethylamino or nitro; The molar ratio of the aromatic aldehyde, pyrrole, copper salt and anhydrous AlCl3 is 1-1.5: 1-1.5: 1-5: 1-5; the molar concentration of pyrrole in DMF is 1 / 500-1 / 1500.

2. A method for synthesizing copper porphyrin from aromatic aldehydes, pyrrole and copper salt according to claim 1, characterized in that: The reaction time is 0.5-3 hours.

3. A method for synthesizing copper porphyrin from aromatic aldehydes, pyrrole and copper salt according to claim 1, characterized in that: The reaction was carried out under refluxing DMF.

4. A method for synthesizing copper porphyrin from aromatic aldehydes, pyrrole and copper salt according to claim 1, characterized in that: The copper salt used in the reaction is copper acetate, copper chloride, copper bromide, copper nitrate or copper sulfate.

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