Main-Product

Ethyl tert-butyl ether (ETBE) is a tertiary alkyl ether with the formula C₆H₁₄O. It is a clear, colorless to pale yellow liquid (boiling point 72–73 °C; melting point –94 °C) with a slightly terpene-like odor. ETBE is only slightly soluble in water (≈1.2 g/100 g at 20 °C) but miscible with ethanol and many organic solvents.

ETBE is produced industrially via the acidic etherification of isobutylene and ethanol. A sulfonated polystyrene–divinylbenzene ion-exchange resin (e.g., Amberlyst-15) typically serves as catalyst.

ETBE is primarily used as an oxygenate gasoline blending component to:

• Raise octane number and improve anti-knock performance to levels comparable with or better than MTBE
• Reduce evaporative emissions, since ETBE lowers Reid Vapor Pressure (RVP) versus ethanol and does not promote phase-separation with water
• Enhance air-quality, cutting carbon monoxide (CO), VOC, and particulates by supplying oxygen in the fuel blend

Unlike MTBE, ETBE’s ethanol origin offers renewable-content credits in regions with bioethanol mandates, and its lower volatility minimizes evaporative losses that contribute to urban smog.

ETBE is widely adopted in Europe and Japan, where bio-ETBE (from fermentation-derived bioethanol) satisfies renewable-fuel directives. Typical blend levels range from 5–20 vol % in gasoline. In contrast, U.S. usage fell sharply post-2006 due to liability concerns over MTBE contamination, though interest in ETBE continues where biofuel targets are enforced.

References

1. Feb 27, 2025 - tert-Butyl ethyl ether - Chemical Book
2. Ethyl tert-butyl ether - Wikipedia
3. ETBE (Ethyl tert-butyl ether) - Ataman Chemical
4. Jun 2006 - Technical Product Bulletin - ETBE (Cas number 637-92-3) - European Fuel Oxygenates Association