Diethyl Oxalate
High-Purity C2 Diester Building Block (Oxalic Acid Diethyl Ester) — Pharmaceutical, Agrochemical, Dye & Fine-Chemical Synthesis
CAS: 95-92-1 EC: 202-464-1 Assay: ≥ 99.0%
Diethyl oxalate (oxalic acid diethyl ester, DEO, CAS 95-92-1) is a high-purity, colourless to pale-yellow liquid diester and one of the most useful two-carbon (C2) building blocks in organic synthesis. Through Claisen condensation, ethoxalylation, and heterocycle formation it introduces the oxalyl group into a wide range of targets, making it a key intermediate for pharmaceuticals (such as barbiturates and quinolone antibacterials), agrochemicals, oxamide and oxanilide light stabilisers, and dyes; it also serves as a solvent for cellulose esters and resins. Royalchem Spain supplies it at ≥ 99% purity, delivered from our Valladolid distribution hub by drum, IBC, or ISO tank with COA and SDS for every batch.
Technical Specifications (COA Data)
| Assay (GC) | ≥ 99.0% |
| Appearance | Colourless to pale-yellow transparent liquid |
| Acidity (as H₂SO₄) | ≤ 0.05% |
| Moisture (KF) | ≤ 0.05% |
| Density (20 °C) | 1.076–1.079 g/cm³ |
| Boiling Point | ≈ 182–186 °C |
| Flash Point | ≥ 75 °C |
*Regulatory: EINECS-listed (EC 202-464-1); supplied in line with EU REACH requirements; manufactured under ISO 9001. GHS — Warning: harmful if swallowed (H302); causes serious eye irritation (H319). A combustible liquid (flash point ≈ 76 °C). Shipped as a Class 6.1 toxic substance (UN 2525, ethyl oxalate, PG III). Moisture-sensitive — hydrolyses slowly to oxalic acid and ethanol; keep dry and sealed. Handle with gloves, eye protection, and adequate ventilation. Always refer to the current SDS.
Key Properties
• Molecular Formula: C₆H₁₀O₄
• Molecular Weight: 146.14
• Boiling Point: ≈ 182–186 °C
• Density (20 °C): ≈ 1.08 g/cm³
Pharmaceutical & API Intermediate
A versatile C2 ethoxalyl building block used via Claisen condensation and heterocycle formation in API synthesis — for example barbiturates (such as phenobarbital), quinolone antibacterials, and other actives requiring an oxalyl unit.
Agrochemicals, Dyes & Light Stabilisers
A building block for agrochemical actives, dye intermediates, and oxamide/oxanilide UV absorbers and light stabilisers, and a precursor to ethyl oxamate and other oxalyl derivatives.
Solvent & Specialty Chemistry
A solvent for cellulose esters (acetate and nitrate) and various resins, and a reactant in transesterification and condensation chemistry for specialty and fine-chemical manufacture.