27 CFR § 21.108-T - Ethyl tertiary butyl ether.

---
identifier: "/us/cfr/t27/s21.108-T"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "27 CFR § 21.108-T - Ethyl tertiary butyl ether."
title_number: 27
title_name: "Alcohol, Tobacco Products and Firearms"
section_number: "21.108-T"
section_name: "Ethyl tertiary butyl ether."
chapter_name: "ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY"
subchapter_number: "A"
subchapter_name: "ALCOHOL"
part_number: "21"
part_name: "FORMULAS FOR DENATURED ALCOHOL AND RUM"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "5 U.S.C. 552(a); 26 U.S.C. 5242, 7805."
regulatory_source: "T.D. ATF-133, 48 FR 24673, June 2, 1983, unless otherwise noted."
cfr_part: "21"
---


# 21.108-T Ethyl tertiary butyl ether.

(a) *Purity.* ≥95.0 percent.

(b) *Color.* Colorless to light yellow.

(c) *Odor.* Terpene-like.

(d) *Specific gravity at 20 °C.* 0.70 to 0.80.

(e) *Boiling point ( °C).* 73.

[T.D. TTB-140, 81 FR 59462, Aug. 30, 2016]