4,4'-Bis(diethylamino) benzophenone
[CAS# 90-93-7]

Identification

• Classification: Organic raw materials >> Ketone compound
• Name: 4,4'-Bis(diethylamino) benzophenone
• Synonyms: bis[4-(diethylamino)phenyl]methanone
• Molecular Formula: C₂₁H₂₈N₂O
• Molecular Weight: 324.46
• CAS Registry Number: 90-93-7
• EC Number: 202-025-4
• SMILES: CCN(CC)C1=CC=C(C=C1)C(=O)C2=CC=C(C=C2)N(CC)CC

Properties

• Melting point: 93-95 °C
• Flash point: 151 °C
• Water solubility: insoluble

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Risk Statements: H315-H319-H335-H400-H411-H413
• Safety Statements: P261-P264-P264+P265-P271-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Carcinogenicity	Carc.	2	H351
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - single exposure	STOT SE	3	H336

Discovery and Applications

4,4'-Bis(diethylamino)benzophenone, commonly known as Michler’s ketone, is an organic compound widely used in the chemical industry, particularly in dye production and photoinitiators. The compound was first synthesized in the late 19th century by German chemist Wilhelm Michler during his research on aromatic ketones. It is characterized by a structure containing two diethylamino groups attached to a benzophenone core, which contributes to its unique properties, especially its reactivity and light-absorbing capabilities.

One of the primary applications of 4,4'-Bis(diethylamino)benzophenone is in the manufacture of triphenylmethane dyes. These dyes are used in textiles, inks, and coatings, offering vibrant colors and high stability. The compound serves as an intermediate in the synthesis of dyes such as crystal violet and malachite green, which are notable for their intense coloration and diverse industrial uses. Its role in dye production has made Michler’s ketone an important building block in the chemical dye industry.

In addition to its use in dye synthesis, 4,4'-Bis(diethylamino)benzophenone is a key component in photoinitiators for UV-curable coatings, inks, and adhesives. Photoinitiators are compounds that absorb light and initiate polymerization when exposed to ultraviolet (UV) radiation. Michler’s ketone, when combined with a co-initiator, generates reactive species that lead to the curing of coatings, making it a critical additive in processes where rapid and efficient hardening is required, such as in the production of optical fibers, electronics, and printing.

Michler’s ketone is also used in the research of organic semiconductors and photoconductive materials. Its molecular structure allows it to participate in electron transfer processes, making it a candidate for use in materials that rely on light-induced conductivity. This application is particularly important in the field of organic electronics, where developing efficient light-absorbing materials is a key focus.

Despite its wide industrial use, 4,4'-Bis(diethylamino)benzophenone has been a subject of scrutiny due to its potential health risks. Studies have indicated that the compound can be carcinogenic, and its use is regulated in certain applications to ensure safety. Manufacturers are required to handle it with care, ensuring that proper safety measures are in place to prevent exposure to harmful levels of the compound.

References

2018. Photofabrication. Photochemistry for Biomedical Applications.
DOI: 10.1007/978-981-13-0152-0_3

2014. Benzophenone UV-Photoinitiators Used in Food Packaging: Potential for Human Exposure and Health Risk Considerations. Toxicants in Food Packaging and Household Plastics.
DOI: 10.1007/978-1-4471-6500-2_6

2009. Three-Dimensional Biodegradable Structures Fabricated by Two-Photon Polymerization. Langmuir : the ACS journal of surfaces and colloids, 25(3).
DOI: 10.1021/la803803m