Dimethyl Oxalate CAS 553-90-2

Introduction to Dimethyl Oxalate

Dimethyl Oxalate is an aliphatic diester consisting of two methyl groups bonded to an oxalate core. Its molecular structure provides two highly reactive ester carbonyl sites, making it an effective acylating and methylating agent. At room temperature, the material appears as a white crystalline solid; above its melting point, it transitions into a clear, colorless liquid. It dissolves readily in most organic solvents including alcohols, ethers and aromatic hydrocarbons, while exhibiting limited solubility in cold water.

The compound features high thermal stability, maintaining structural integrity during high-temperature catalytic hydrogenation processes without premature decomposition. Its distinct phase transition behavior enables purification via crystallization and convenient liquid handling when trace-heated, supporting both batch and continuous industrial processes.

Dimethyl Oxalate Chemical & Physical Properties

Applications of Dimethyl Oxalate

Coal-to-Ethylene Glycol (CTEG) process: Acts as the core intermediate in modern coal chemical engineering. It undergoes catalytic hydrogenation over copper-based catalysts to yield high-purity ethylene glycol and methanol. This non-petroleum pathway provides a highly efficient, cost-effective route to polyester-grade glycols.

Pharmaceutical and agrochemical synthesis: Functions as a key building block for constructing heterocyclic rings and complex active pharmaceutical ingredients. It is used to perform Claisen condensations and synthesize pyrazine, pyrimidine and thiazole derivatives for drug and crop protection chemistry.

Solvent and plasticizer intermediates: Utilized as a high-boiling solvent in specialized coating formulations and as a precursor for synthesizing various oxamide-based plasticizers and stabilizers for polymer matrices.

Storage & Safety Precautions for Dimethyl Oxalate

• Store in a climate-controlled warehouse. Below 54 °C the material remains solid. Facilities handling the liquid form must use trace-heated, insulated piping and storage tanks to prevent line blockages during winter operations.
• Keep drums tightly sealed. Prolonged exposure to atmospheric humidity causes slow hydrolysis, generating methanol and oxalic acid, which increases acidity and degrades the material for sensitive catalytic applications.
• Wear chemical splash goggles, nitrile gloves and dust masks during solid transfer or molten liquid decanting. The liquid and dust are mild irritants to eyes, skin and the respiratory tract. Ensure adequate ventilation to prevent vapor accumulation in enclosed spaces.
• When melting solid drums for reactor charging, apply gentle warm water baths or low-pressure steam jackets. Avoid localized high-temperature heating coils, which can cause thermal degradation and darkening of the molten batch.

Dimethyl Oxalate FAQ

Q: How is Dimethyl Oxalate utilized in ethylene glycol production?

A: It acts as the core intermediate in the coal-to-ethylene glycol process. It undergoes catalytic hydrogenation over copper-based catalysts to yield high-purity ethylene glycol and methanol, providing a cost-effective alternative to petroleum-based routes.

Q: Why does Dimethyl Oxalate solidify during winter transit?

A: It has a melting point of approximately 54 °C. Below this temperature, it forms a white crystalline solid. To restore the liquid state for reactor charging, gently heat storage drums using warm water baths or low-pressure steam jackets.

Q: What safety precautions are necessary when handling Dimethyl Oxalate?

A: It is a combustible solid/liquid and a mild irritant to skin, eyes and the respiratory tract. Wear chemical splash goggles, nitrile gloves and dust masks during transfer. Ensure adequate ventilation to prevent vapor accumulation in enclosed spaces.