Diethyl squarate

Also known as: 3,4-Diethoxy-3-cyclobutene-1,2-dione, Squaric acid diethyl ester, 3,4-Diethoxycyclobut-3-ene-1,2-dione, Diethyl squarate, 3,4-Diethoxy-3-cyclobutene-1,2-dione 98%, 3,4-Diethoxy-3-cyclobuten-1,2-dion, SQUARIC ACID DIETHYL ESTER, MFCD00001333

Diethyl squarate (CAS 5231-87-8) is a compound in the Organic Acids category listed in the Jingsj chemical database. It has the molecular formula C8H10O4 and a molecular weight of 170.163 g/mol. Key properties include a melting point of 19 °C, a boiling point of 325.7±0.0 °C at 760 mmHg, a density of 1.2±0.1 g/cm3 and a flash point of 135.4±30.7 °C. It is classified under GHS with signal word Danger and hazard statements H315 — Causes skin irritation, H317 — May cause an allergic skin reaction and H319 — Causes serious eye irritation. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 5231-87-8
Jingsj CID: J-1991498-8
Molecular Formula: C₈H₁₀O₄
Molecular Weight: 170.163 g/mol
Category: Organic Acids
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	19 °C
Boiling Point	325.7±0.0 °C at 760 mmHg
Density	1.2±0.1 g/cm3
Flash Point	135.4±30.7 °C
Exact Mass	170.057907
PSA	52.60000
LogP	-0.15
Vapor Pressure	0.0±0.7 mmHg at 25°C
Refractive Index	1.477
Additional Property	insoluble

GHS Safety & Compliance

Irritant / Health HazardSignal word: Danger

H315 — Causes skin irritation
H317 — May cause an allergic skin reaction
H319 — Causes serious eye irritation
H334 — May cause allergy or asthma symptoms if inhaled
H335 — May cause respiratory irritation

Frequently Asked Questions

What is the CAS number of Diethyl squarate?

The CAS number of Diethyl squarate is 5231-87-8.

What are the molecular formula and molecular weight of Diethyl squarate?

Diethyl squarate has molecular formula C8H10O4 and molecular weight 170.163 g/mol.

Is Diethyl squarate hazardous?

Diethyl squarate has GHS signal word Danger and hazard statements H315 — Causes skin irritation; H317 — May cause an allergic skin reaction; H319 — Causes serious eye irritation.

What are the upstream and downstream products of Diethyl squarate?

For Diethyl squarate, Upstream Products: Ethanol, Squaric acid, Triethyl orthoformate; Downstream Products: 3,4-Bis(dimethylamino)cyclobut-3-ene-1,2-dione, 3-Amino-4-ethoxycyclobut-3-ene-1,2-dione.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated: 8/21/2026

How to cite: Jingsj. "Diethyl squarate (CAS 5231-87-8)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1991498-8 (accessed 2026-11-09).

Data for reference only; verify product details with suppliers before purchase.