Triphenylphosphine oxide

CAS 791-28-6

U.S. production volumes are classified as confidential business information.

US productionCBI

Confidential Business Information. The EPA withholds this volume because publishing it could reveal the reporting company's trade secrets.

Import value, 2024$598M

Top sourceChina 89%

At least one company claimed its 2019 production or import volume for this chemical as confidential, so EPA withholds it.

Why supply is unknown

Production is reported production, not a complete census of factories. US production volume is confidential. Production reporting year: 2019. Import value and source-country shares describe a shared customs category, not a separate chemical measurement.

Where It Comes From

Customs basis: HS 293149 · basket

EPA reports by year

2019: US production Confidential · Imports Confidential

These shares come from HS customs code 293149, which covers 114 tracked chemicals in total. They estimate the category's origin mix, not this chemical specifically.

Source Countries

Country of origin for US imports, from Census customs data (2024).

CN 89%ChinaIN 4%IndiaCA 3%CanadaDE 2%GermanyAR 1%Argentina

United Kingdom
Italy
Mexico
Japan
Switzerland
Hong Kong
Ukraine
Finland
Sweden
Spain
Poland
Slovakia
Netherlands
Singapore
Taiwan
South Korea
Czech Republic

Domestic parents -- activity not disclosed (1)

EPA records name a US company for this chemical but do not disclose whether the company made it here or imported it.

Pmc Organometallix

EPA-registered importers (1)

Companies that report making or importing this chemical to the EPA. Registration is US-centric and does not indicate import origin.

Arlanxeo

Why It Matters

Sectors

Plastics & Rubber

Downstream UsesNot recorded

FDA Shortage Status

Whether any manufacturer currently reports this drug as in shortage on the FDA Drug Shortages database. "Active Shortage" means at least one presentation has status "current."

No FDA shortage records

Industrial Uses

•Catalyst in Synthetic Rubber Manufacturing (100%)Processing as a reactant

Chemical Identity

CAS791-28-6

PubChem CID13097

DTXSIDDTXSID2022121

FormulaC18H15OP

Mol. Weight278.3 g/mol

SMILESC1=CC=C(C=C1)P(=O)(C2=CC=CC=C2)C3=CC=CC=C3

Data Sources

EPA CompTox (DSSTox) · DTXSID2022121Retrieved 2026-04-06
PubChem · compound 13097Retrieved 2026-04-06
EPA Chemical Data ReportingReporting year: 2019 · Retrieved 2026-10-04
EPA Chemical Data ReportingReporting year: 2019 · Retrieved 2026-10-04
US Census international tradeReporting year: 2024 · Retrieved 2026-10-04

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Brief citations

Triphenylphosphine oxide (CAS 791-28-6) https://chemicalindependence.com/chemical/791-28-6/ EPA CompTox (DSSTox): DTXSID2022121. Retrieved 2026-04-06. https://comptox.epa.gov/dashboard/chemical/details/DTXSID2022121 PubChem: 13097. Retrieved 2026-04-06. https://pubchem.ncbi.nlm.nih.gov/compound/13097 EPA Chemical Data Reporting: 791-28-6. Reporting year: 2019. https://www.epa.gov/chemical-data-reporting EPA Chemical Data Reporting: CAS 791-28-6. Reporting year: 2019. https://www.epa.gov/chemical-data-reporting US Census international trade: HS 293149 for CAS 791-28-6. Reporting year: 2024. https://usatrade.census.gov/