- ▸ Aminobenzophenone sensitizer/co-initiator that extends Type II cure to longer wavelengths in UV coatings (Coatings & Construction)
- ▸ Photosensitizer for UV/UV-LED inks, often paired with thioxanthones (Industrial Manufacturing)
- ▸ Sensitizes cure of pigmented UV-curable plastics and adhesives (Plastics & Polymers)
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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4,4′-Bis(diethylamino)benzophenone is an aminoketone photosensitizer and co-synergist — an electron-rich benzophenone that boosts other photoinitiators (especially thioxanthones and benzophenones) and extends response toward visible light. It is used as a sensitizer/co-initiator, not as a standalone surface initiator. Identity: CAS 90-93-7.
What it is
4,4′-Bis(diethylamino)benzophenone (CAS 90-93-7, the diethyl analogue of Michler’s ketone) is a yellow solid. Its two diethylamino groups make it a strong electron donor, so it works as a photosensitizer/co-initiator that amplifies a primary initiator.
How it cures
Rather than curing alone, it acts as a sensitizer/donor: it absorbs and transfers energy/electrons to a primary Type II initiator (e.g. a thioxanthone or benzophenone), extending spectral response and accelerating cure, including toward the visible. It is dosed at low levels as part of an initiator package.
Applications
Used as a sensitizer/co-initiator in UV/visible coatings and inks, paired with a thioxanthone (ITX) or benzophenone and an amine synergist (EDB) to broaden and speed cure.
Forms, grades and handling
It is supplied as a yellow crystalline solid. Photoinitiators are light-sensitive — store cool, dry and dark, away from light and ignition sources. Handle per the current Safety Data Sheet (SDS); each lot ships with a Certificate of Analysis (CoA) and Technical Data Sheet (TDS).
Bulk supply and RFQ
RawSource sources 4,4′-Bis direct from producers in bulk, with CoA, TDS and SDS per lot. Tell us your lamp (mercury or LED wavelength), system (clear or pigmented) and cure target, and we will quote the right grade. Compare the full range and selection logic in the photoinitiators guide.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical / type | Photosensitizer (aminoketone co-initiator) |
| Photoinitiator type | Photosensitizer / amine co-synergist |
| Absorption | Visible / long-UV |
| Function | Sensitizer/donor; dosed at low levels in a package |
| CAS Number | 90-93-7 |
| Molecular Formula | C21H28N2O |
| Molecular Weight | 324.5 g/mol |
| Handling | Light-sensitive; refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 202-025-4
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Frequently Asked Questions
What is 4,4′-bis(diethylamino)benzophenone used for?
4,4′-Bis(diethylamino)benzophenone (CAS 90-93-7) is a photosensitizer/co-synergist used at low levels to boost Type II photoinitiators (thioxanthones, benzophenones) and extend spectral response toward visible light; it is not used as a standalone surface initiator.
Is it a photoinitiator or a sensitizer?
It functions mainly as a photosensitizer/co-initiator — an electron donor that amplifies a primary initiator — rather than cleaving on its own.
How is bulk 4,4′-bis(diethylamino)benzophenone supplied and quoted?
RawSource supplies 4,4′-bis(diethylamino)benzophenone in bulk with CoA, TDS and SDS per lot. Pricing is quote-based on grade and volume; submit an RFQ with your target quantity.
What is the REACH and TSCA regulatory status of 4,4'-Bis(diethylamino)benzophenone?
4,4'-Bis(diethylamino)benzophenone (CAS 90-93-7) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 202-025-4).