Pyridine-2,6-dicarboxylic acid is an organic compound with CAS 499-83-2 and chemical formula C7H5NO4. It is a white or light yellow crystalline powder with a slight irritating odor. Soluble in organic solvents such as water, ethanol, and ether, slightly soluble in benzene, chloroform, etc. Stable at room temperature, but easily decomposes at high temperatures. It has multiple uses and can be used to synthesize dyes, pigments, spices, and other products. In addition, it can also be used as a food additive and cosmetic ingredient. It has a wide range of applications in many fields, and with the development of science and technology, its application areas will continue to expand and deepen. However, attention should also be paid to the safety and environmental impact during use, and research on the resource utilization of wastewater and waste residue should be strengthened. It is an important intermediate in drug synthesis with a wide range of applications. It can be used to synthesize 2,6-diacetylpyridine, 2,6-diamino-4-chloropyridine, and can also be used for the next step of synthesizing metal ligand compounds, functional materials, and pharmaceutical intermediates.
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There are various synthesis routes for Pyridine-2,6-dicarboxylic acid, and the following are some common synthesis methods:
Method 1: The detailed steps for synthesizing Pyridine-2,6-dicarboxylic acid from 4-bromopyridine-2,6-dicarboxylic acid diethyl ester are as follows:
C11H12BrNO4+2NaOH → H2O+C7H5NO4+2 (CH3CH2OCO) 2Na
Reaction principle:
Pyridine-2,6-dicarboxylic acid can be synthesized by the reaction of 4-bromopyridine-2,6-dicarboxylic acid diethyl ester with sodium hydroxide solution. During the reaction, the bromine atom in 4-bromopyridine-2,6-dicarboxylic acid diethyl ester is replaced by hydroxide ions in sodium hydroxide solution, forming Pyridine-2,6-dicarboxylic acid.
Experimental steps:
(1) Weigh a certain amount of 4-bromopyridine-2,6-dicarboxylic acid diethyl ester, add it to an appropriate amount of organic solvents (such as methanol, ethanol, etc.), and stir evenly.
(2) Slowly add sodium hydroxide solution to the mixture, control the reaction temperature to around room temperature, and stir evenly.
(3) After a period of reaction, observe the changes in the reaction mixture. When the mixture becomes clear, it indicates that the reaction has been completed.
(4) Filter the reaction mixture to obtain the filtrate and filter residue.
(5) Rinse the filter residue with water to obtain a crude product of Pyridine-2,6-dicarboxylic acid.
(6) Recrystallize the crude product to obtain Pyridine-2,6-dicarboxylic acid with high purity.
Method 2: The detailed steps for synthesizing Pyridine-2,6-dicarboxylic acid from 4-chloropyridine-2,6-dicarboxylic acid methyl ester are as follows:
C9H8ClNO4+NaOH → H2O+C7H5NO4+(CH3COO) Na
Reaction principle:
Pyridine-2,6-dicarboxylic acid can be synthesized by the reaction of 4-chloropyridine-2,6-dicarboxylic acid methyl ester with sodium hydroxide solution. During the reaction, the chlorine atom in 4-chloropyridine-2,6-dicarboxylic acid methyl ester is replaced by hydroxide ions in sodium hydroxide solution, forming Pyridine-2,6-dicarboxylic acid.
Experimental steps:
(1) Weigh a certain amount of 4-chloropyridine-2,6-dicarboxylic acid methyl ester, add it to an appropriate amount of organic solvents (such as methanol, ethanol, etc.), and stir evenly.
(2) Slowly add sodium hydroxide solution to the mixture, control the reaction temperature to around room temperature, and stir evenly.
(3) After a period of reaction, observe the changes in the reaction mixture. When the mixture becomes clear, it indicates that the reaction has been completed.
(4) Filter the reaction mixture to obtain the filtrate and filter residue.
(5) Rinse the filter residue with water to obtain a crude product of Pyridine-2,6-dicarboxylic acid.
(6) Recrystallize the crude product to obtain Pyridine-2,6-dicarboxylic acid with high purity.
Method 3: The detailed steps for synthesizing Pyridine-2,6-dicarboxylic acid from 3-bromo-2,6-dimethylpyridine are as follows:
C7H8BrN+NaOH → H2O+C7H5NO4+NaBr
Reaction principle:
Pyridine-2,6-dicarboxylic acid can be synthesized by the reaction of 3-bromo-2,6-dimethylpyridine with sodium hydroxide solution. During the reaction, the bromine atom in 3-bromo-2,6-dimethylpyridine is replaced by hydroxide ions in sodium hydroxide solution, forming Pyridine-2,6-dicarboxylic acid.
Experimental steps:
(1) Weigh a certain amount of 3-bromo-2,6-dimethylpyridine, add it to an appropriate amount of organic solvents (such as methanol, ethanol, etc.), and stir evenly.
(2) Slowly add sodium hydroxide solution to the mixture, control the reaction temperature to around room temperature, and stir evenly.
(3) After a period of reaction, observe the changes in the reaction mixture. When the mixture becomes clear, it indicates that the reaction has been completed.
(4) Filter the reaction mixture to obtain the filtrate and filter residue.
(5) Rinse the filter residue with water to obtain a crude product of Pyridine-2,6-dicarboxylic acid.
(6) Recrystallize the crude product to obtain Pyridine-2,6-dicarboxylic acid with high purity.
Method 4: The detailed steps for generating 2,6-pyridinedioic acid by reacting methyl ortho aminobenzoate with potassium cyanide are as follows:
The chemical equation for the reaction of methyl ortho aminobenzoate with potassium cyanide to produce 2,6-pyridinedioic acid is as follows:
CH3COO-NH2+H+CH3COOH+KCN → CH3COO-NH-CO-NH-COOH+CH3COOH+KOH+H2O
Experimental preparation:
Methyl ortho aminobenzoate, also known as methyl ortho aminobenzoate, is an organic compound with a pungent odor.
Potassium cyanide: is an inorganic compound that is highly toxic and poses serious harm to the human body.
Organic solvents, such as methanol, ethanol, etc., are used to dissolve methyl ortho aminobenzoate and potassium cyanide.
Catalysts: such as sulfuric acid or hydrochloric acid, used to accelerate reactions.
Experimental steps:
(1) Add an appropriate amount of organic solvent to the beaker, then add an appropriate amount of methyl ortho aminobenzoate and stir evenly.
(2) Slowly add potassium cyanide to the mixture while dropwise adding the catalyst.
(3) Heat the mixture to a certain temperature and maintain it for a period of time to allow the reaction to proceed fully.
(4) After the reaction is completed, cool the mixture to room temperature and filter to obtain the crude product.
(5) Recrystallize the crude product to obtain high-purity 2,6-pyridinedioic acid.
Method 5: The detailed steps for generating 2,6-pyridinedioic acid by reacting o-aminobenzoic acid with sodium cyanide are as follows:
The chemical equation for the reaction of o-aminobenzoic acid with sodium cyanide to produce 2,6-pyridinedioic acid is as follows:
CH3COO-NH2+H+CH3COOH+NaCN → CH3COO-NH-CO-NH-COOH+CH3COOH+NaOH+H2O
Experimental preparation:
O-aminobenzoic acid, also known as o-aminomethylbenzoic acid, is an organic compound with a pungent odor.
Sodium cyanide: It is an inorganic compound that is highly toxic and poses serious harm to the human body.
Organic solvents: such as methanol, ethanol, etc., used to dissolve o-aminobenzoic acid and sodium cyanide.
Catalysts: such as sulfuric acid or hydrochloric acid, used to accelerate reactions.
Experimental steps:
(1) Add an appropriate amount of organic solvent to the beaker, then add an appropriate amount of o-aminobenzoic acid and stir evenly.
(2) Slowly add sodium cyanide to the mixture while dropwise adding the catalyst.
(3) Heat the mixture to a certain temperature and maintain it for a period of time to allow the reaction to proceed fully.
(4) After the reaction is completed, cool the mixture to room temperature and filter to obtain the crude product.
(5) Recrystallize the crude product to obtain high-purity 2,6-pyridinedioic acid.
matters needing attention
1. During the experiment, it is necessary to strictly control the reaction conditions, such as temperature, time, amount of catalyst, etc., to ensure the accuracy and reliability of the experimental results.
2. Due to the high toxicity of certain compounds, necessary safety measures need to be taken during the experiment, such as wearing protective goggles, gloves, etc.
3. After the experiment, it is necessary to properly dispose of the waste liquid to avoid pollution to the environment.
4. Through the above methods, we can successfully synthesize 2,6-pyridinedioic acid. In practical operation, it is necessary to pay attention to controlling the reaction conditions to ensure the accuracy and reliability of the experimental results. At the same time, the treatment of wastewater and waste residue also needs to consider issues such as environmental protection and resource utilization.