Diprop-2-en-1-yl (2Z)-but-2-enedioate

CAS 999-21-3

2-Butenedioic acid (2Z)-, 1,4-di-2-propen-1-yl ester

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$139M

Import volumeZero

Top sourceChina 67%

At least one company claimed its 2023 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: 2023. Import value and source-country shares describe a shared customs category, not a separate chemical measurement.

Where It Comes From

Customs basis: HS 291719 · basket

EPA reports by year

2023: US production Confidential · Imports Zero

These shares come from HS customs code 291719, which covers 176 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 67%ChinaCA 13%CanadaAT 4%AustriaIN 4%IndiaJP 4%Japan

Taiwan
Netherlands
Switzerland
Mexico
South Africa
Denmark
Malaysia
Ukraine
Colombia
Hong Kong
Slovakia

EPA-registered manufacturers (2)

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

Mitsubishi Chemical Group · JP Japan

Mitsubishi Chemical America

Why It Matters

Sectors

Core Chemicals

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

Used in 2 sectors as 1 functional role.

•Intermediate in All Other Chemical Product and Preparation Manufacturing (100%)Processing as a reactant
•Intermediate in All Other Basic Organic Chemical Manufacturing (100%)Processing—incorporation into formulation, mixture, or reaction product

Chemical Identity

CAS999-21-3

PubChem CIDNot recorded

DTXSIDDTXSID3044752

FormulaC10H12O4

Mol. Weight196.202 g/mol

SMILESC=CCOC(=O)\C=C/C(=O)OCC=C

Data Sources

EPA TSCA InventoryRetrieved 2026-04-29
EPA Chemical Data ReportingReporting year: 2023 · Retrieved 2026-10-04
EPA Chemical Data ReportingReporting year: 2023 · Retrieved 2026-10-04
US Census international tradeReporting year: 2024 · Retrieved 2026-10-04

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Brief citations

Diprop-2-en-1-yl (2Z)-but-2-enedioate (CAS 999-21-3) https://chemicalindependence.com/chemical/999-21-3/ EPA TSCA Inventory: CAS 999-21-3. Retrieved 2026-04-29. https://www.epa.gov/tsca-inventory EPA Chemical Data Reporting: 999-21-3. Reporting year: 2023. https://www.epa.gov/chemical-data-reporting EPA Chemical Data Reporting: CAS 999-21-3. Reporting year: 2023. https://www.epa.gov/chemical-data-reporting US Census international trade: HS 291719 for CAS 999-21-3. Reporting year: 2024. https://usatrade.census.gov/