The Production Process of Dimethyl 2,3-quinolinedicarboxylate

The Production Process of Dimethyl 2,3-quinolinedicarboxylate in the Chemical Industry

Dimethyl 2,3-quinolinedicarboxylate, also known as DMQ, is a white to off-white solid with a strong, unpleasant odor.
It is used as a catalyst in the production of polyethylene terephthalate (PET), a widely used plastic in the manufacturing of bottles, fibers, and other products.
The production process of DMQ involves several steps, including the synthesis of 2,3-dimethylquinoxaline, its conversion to 2,3-dimethyl-5,6-dihydro-1H-quinolizine-1,4-dione, and finally the esterification of the latter compound with 2,3-dimethyl-2,3-dihydro-1H-quinolizine-1,4-dione.

Step 1: Synthesis of 2,3-dimethylquinoxaline

The synthesis of 2,3-dimethylquinoxaline involves the reaction of dimethyl amine and acrolein in the presence of a solvent such as water or methanol.
The reaction produces a mixture of compounds, including 2,3-dimethylquinoxaline, which is then isolated using a variety of techniques such as filtration, crystallization, or chromatography.

Step 2: Conversion of 2,3-dimethylquinoxaline to 2,3-dimethyl-5,6-dihydro-1H-quinolizine-1,4-dione

The conversion of 2,3-dimethylquinoxaline to 2,3-dimethyl-5,6-dihydro-1H-quinolizine-1,4-dione involves a series of reactions such as hydrolysis, oxidation, and reduction.
The process typically involves the use of chemical reagents such as sodium hydroxide, nitric acid, and hydrogen gas.

Step 3: Esterification of 2,3-dimethyl-2,3-dihydro-1H-quinolizine-1,4-dione with 2,3-dimethyl-2,3-dihydro-1H-quinolizine-1,4-dione

The esterification of 2,3-dimethyl-2,3-dihydro-1H-quinolizine-1,4-dione with 2,3-dimethyl-2,3-dihydro-1H-quinolizine-1,4-dione involves the reaction of the two compounds in the presence of a strong acid catalyst such as sulfuric acid.
The reaction produces dimethyl 2,3-quinolinedicarboxylate, which can then be isolated using techniques such as filtration, crystallization, or chromatography.

The Production Process of DMQ in Industry

The production of DMQ involves several steps, each of which requires careful control and monitoring to ensure the quality and purity of the final product.
The process typically involves the following steps:

1. Synthesis of 2,3-dimethylquinoxaline: This is the first step in the production of DMQ and involves the reaction of dimethyl amine and acrolein in the presence of a solvent such as water or methanol.
   
2. Conversion of 2,3-dimethylquinoxaline to 2,3-dimethyl-5,6-dihydro-1H-quinolizine-1,4-dione: This step involves a series of reactions such as hydrolysis, oxidation, and reduction, typically using chemical reagents such