Diethyl Ether

SolventC4H10OCAS: 60-29-7Shelf life: 12 mo
Diethyl Ether
Image: Giulio Pietrobon — CC BY 4.0

Physical Properties

Also known as: Ether, Ethoxyethane, Sulfuric Ether

Diethyl ether (C₄H₁₀O; CAS 60-29-7), commonly called ether, is a highly volatile organic solvent used in photography primarily as the solvent for nitrocellulose in collodion preparation.[1] It is one of two solvents (with ethanol) in USP-grade photographic collodion, where its rapid evaporation rate controls the drying time of the coating on glass plates. Ether's photographic role is essentially limited to wet-plate collodion work; other darkroom chemistries rarely need it.

Photographic uses

  • Collodion solvent: Diethyl ether dissolves nitrocellulose at 4–5% concentration in a 2:1 or 3:1 ether-to-ethanol mix, producing the characteristic viscous collodion syrup. The ether evaporates ~3× faster than the ethanol, driving the gelation of the coating on the plate.
  • Cleaning nitrocellulose films and residues: A small amount of ether dissolves cured collodion film, useful for cleaning glass plates after failed exposures.
  • Historical organic chemistry: A few 19th-century developer formulas used ether as a co-solvent for slightly-soluble organic developing agents; essentially obsolete.

Practical notes

Supplied as a colorless liquid with a characteristic sweet odor. Exceptionally volatile — boiling point 34.6 °C — and the vapor is 2.5× denser than air, pooling at the floor where it is easily ignited by static electricity or pilot lights.

Peroxide formation: diethyl ether slowly accumulates explosive peroxides on exposure to air and light. A bottle of ether that has been open for months is potentially hazardous to handle (the peroxide residue detonates on shock or concentration). Purchase ether in small quantities; use within a year; discard old stock through a hazardous-waste stream, never by evaporation or drain disposal.

Anhydrous vs stabilized: commercial "ACS ether" is stabilized with BHT or similar antioxidants to slow peroxide formation. Anhydrous ether for specific chemistry is unstabilized and requires refrigerated dark storage with antioxidant handling.

Related compounds

Ethanol is the second collodion co-solvent. Isopropyl alcohol substitutes for ethanol in some modern collodion variants. Petroleum ether (a mixture of low-boiling alkanes) is NOT the same as diethyl ether; the names are easily confused.

Safety Notes

Acute hazards

Diethyl ether is the most hazardous common solvent in darkroom chemistry:

  • Extremely flammable liquid (H224): flash point −45 °C. Ignites from static electricity, pilot lights, or hot surfaces.
  • Harmful if swallowed (H302).
  • Narcotic (H336): inhalation causes drowsiness, dizziness, and at high concentrations loss of consciousness. Ether was the first surgical anesthetic (1846).
  • Irritating to eyes and respiratory tract.

Fire & reactivity

  • Flash point −45 °C — lower than almost any other common laboratory solvent. Keep away from ALL ignition sources, including electrical switch sparks and static discharge.
  • Vapor density 2.5× air: ether vapor pools at the floor and travels along floor surfaces to distant ignition sources. "Contained" spills are rarely contained in practice.
  • Explosive peroxide formation: old bottles of ether are shock-sensitive. Never distill or evaporate aged ether — the peroxides concentrate with the solvent and detonate.
  • Incompatibilities: Strong oxidizers (peroxides, permanganates, nitrates), reducing metals (sodium, potassium).

Storage & handling

  • Personal protective equipment: Nitrile gloves (note: ether slowly dissolves nitrile — change gloves every 10 minutes of contact), safety goggles, long-sleeved clothing, closed-toe shoes. Avoid synthetic fabrics (static ignition risk — cotton preferred).
  • Ventilation: Use outdoors, or in a dedicated fume hood with spark-proof exhaust. A residential darkroom with open windows is not adequate ventilation for substantive ether work.
  • Storage: Tightly sealed amber glass bottle in a cool dark cabinet designed for flammable solvents. Maximum 1 L stock. Date the bottle on opening; discard after 12 months regardless of remaining volume.
  • Ignition-source audit: Before opening an ether bottle, verify no pilot lights, hot plates, electric heaters, smoking materials, or other ignition sources are anywhere in the airflow path.

First aid

Consult the full Sigma-Aldrich Safety Data Sheet for authoritative first-aid instructions.[2]

  • Skin contact: Rinse with water; no medical attention needed for brief contact (though repeated exposure causes skin drying).
  • Eye contact: Flush with running water for at least 15 minutes.
  • Inhalation: Move to fresh air immediately. Seek emergency medical attention for any loss of consciousness, persistent dizziness, or breathing difficulty.
  • Ingestion: Rinse mouth. Seek medical attention immediately; ether ingestion produces rapid CNS depression.

References

  1. BOOK Crawford, William. The Keepers of Light: A History and Working Guide to Early Photographic Processes 1st ed. Morgan & Morgan, 1979. ISBN 0-87100-158-6. ↩
  2. WEB Sigma-Aldrich (Merck KGaA). Sigma-Aldrich Safety Data Sheets Sigma-Aldrich. https://www.sigmaaldrich.com/US/en/search/safety-data-sheets ↩

Reference databases

Last reviewed 2026-04-22