Trichloromonofluoromethane

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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CCl₃F 137.37

Methane, trichlorofluoro-;

Trichlorofluoromethane CAS RN®: 75-69-4.

1 DEFINITION

Trichloromonofluoromethane contains NLT 99.6% and NMT 100.0% of trichloromonofluoromethane (CCl₃F), calculated on the anhydrous basis.

2 IDENTIFICATION

A. The IR absorption spectrum, determined in a 10-cm cell with sodium chloride windows, at atmospheric pressure, exhibits maxima, among others, at the following wavelengths, in μm: 4.67 (m), 5.95 (m), 7.28 (s), 8.06 (m), 9.2 (vs), 10.7 (vs), 11.8 (vs), and 13.4 (m). The stronger maxima are best obtained at pressures less than 10 mm of mercury.

3 ASSAY

3.1 Procedure

System suitability solution: Introduce a liquid-phase mixture of dichlorodifluoromethane, dichlorotetrafluoroethane, and

trichloromonofluoromethane into an evacuated headspace vial.

Sample solution: Introduce the liquid phase of Trichloromonofluoromethane into an evacuated headspace vial.

3.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 2-mm × 1.8-m stainless steel; 1% phase G25 on support S12

Temperatures

Injection port: 110°

Detector: 200°

Column: See Table 1.

Table 1

Carrier gas: Helium

Flow rate: 20 mL/min

Headspace sampler: The bath temperature is 100°, the valve/loop temperature is 105°, and the sampling time is 3 s. Make adjustments as

necessary to optimize peak areas to record trace-level impurities.

3.3 System suitability

Sample: Gas phase headspace of the System suitability solution

[Note—The relative retention times for dichlorodifluoromethane, dichlorotetrafluoroethane, and trichloromonofluoromethane are 0.5, 0.8, and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between dichlorotetrafluoroethane and trichloromonofluoromethane

3.4 Analysis

Sample: Gas phase headspace of the Sample solution

Calculate the percentage of trichloromonofluoromethane (CCl₃F) in the portion of Trichloromonofluoromethane taken.

Acceptance criteria: 99.6%–100.0% on the anhydrous basis

4 IMPURITIES

Inorganic Chlorides

Sample: 7 g

Analysis: Place 5 mL of anhydrous methanol in a test tube, add 3 drops of a saturated solution of silver nitrate in anhydrous methanol, shake, and add the Sample.

Acceptance criteria: No opalescence or turbidity is produced.

Chromatographic Purity

Analysis: In the chromatogram from the Assay, identify the dichlorodìluoromethane and dichlorotetrafluoroethane peaks from relative retention times of those peaks in the chromatogram of the System suitability solution.

Acceptance criteria

Sum of the peak areas for dichlorodifluoromethane and dichlorotetrafluoroethane: NMT 0.2% of the total of all peak areas

Sum of the areas of all peaks other than that for trichloromonofluoromethane: NMT 0.4% of the total of all peak areas.

5 SPECIFIC TESTS

Boiling Temperature

Analysis: Determine as directed in Propellants 〈602〉.

Acceptance criteria: Approximately 24°

Water

Analysis: Determine as directed in Propellants 〈602〉, and Water Deterimination, Method Ic 〈921〉.

Acceptance criteria: NMT 0.001%

High-Boiling Residues

Analysis: Determine as directed in Propellants 〈602〉.

Acceptance criteria: NMT 0.01%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight cylinders, and avoid exposure to excessive heat.