2-Methyl-4'-(methylthio)-2-morpholinopropiophenone

Application fields

2-Methyl-4'-(Methylthio)-2-Morpholinopropiophenone is an efficient UV photoinitiator for initiating UV polymerization of unsaturated prepolymer systems, Such as acrylic resins and monofunctional and multifunctional vinyl monomers. The initiator molecule has a certain light absorption capacity in the ultraviolet region (250-400 nm) or the visible region (400-800 nm). After direct or indirect absorption of light energy, the initiator molecules transition from the ground state to the excited singlet state, through intersystem conversion to excited triple state. After undergoing a single molecular or bimolecular chemistry, initiator molecules produce reactive debris that initiates polymerization of the monomers, which may be free radicals, cations, anions, etc. According to the different initiation mechanism, the photoinitiator can be divided into free radical polymerization photoinitiator and cationic photoinitiator, among which the most widely used is free radical polymerization photoinitiator. The characteristic of high absorbency of 2-Methyl-4'-(Methylthio)-2-Morpholinopropiophenone makes it particularly suitable for UV curable inks and colored coatings. UV inks contain a greater amount of photoinitiator, and it is these photoinitiators that promote the rapid drying of the ink during the printing process. These photoinitiators themselves are not stable, even in the dark, and it is also prone to dark reaction, resulting in one by one ink glue nucleus, followed by a large area of retrogradation. Especially in the preservation of metal ink, similar situation occur more often. Therefore, it is recommended that the ink pigment and the binder separately stored. If used, stir and mix the two with a large machine.
Highly efficient photoinitiator can be used in UV curing systems to extend storage with non-yellowing for a long time. It is an initiator specifically for pigmented UV-curable coatings, inks and adhesives colored solidification system, and it could be used with184, ITX and other initiators. It can be used for colored ink systems, paper/metal and plastic varnish and electronic inks. It is also as a UV absorber for cosmetics and other industries with suggested supplementation of 2-6%.

Application

Used as an initiator in a photo-curable material
UV-curable coatings and inks
Highly efficient photoinitiator can be used in UV curing systems to extend storage with non-yellowing for a long time.

Chemical Properties

White powder

Uses

Photoinitiator-907 is an efficient UV photoinitiator for initiating UV polymerization of unsaturated prepolymer systems.

Flammability and Explosibility

Non flammable

Chemical Reactivity

Photoinitiator-907 (2-Methyl-4′-(methylthio)-2-morpholinopropiophenone) is a highly efficient photoinitiator which undergoes standard Norrish Type I photocleavage.

Synthesis

In a 1000 ml three-necked flask, 400 ml of ethylene dichloride and 200 g (2.3 moles) of morpholine were added, 26.7 g (0.2 moles) of aluminum trichloride was added slowly, and the reaction temperature was controlled to be 40°C or less. The reaction mixture was stirred for 0.5 hours. Subsequently, 136.5 g (0.5 mole) of intermediate a was added in batches, keeping the temperature below 40 °C. After the addition was completed, the reaction mixture was heated to 40 °C and continued to be stirred for 6 hours, during which the content of intermediate a was monitored by GC analysis until it was less than 0.5% to determine the end of the reaction. Upon completion of the reaction, the reaction solution was slowly poured into a beaker containing 1000 mL of ice water for stirring and hydrolysis. After hydrolysis, the pH was adjusted with 30% aqueous sodium hydroxide solution to 14. The reaction mixture was transferred to a separatory funnel to separate the organic layer. The organic layer was washed twice with water, followed by distillation under reduced pressure to remove dichloroethane. After desolventization, 500 ml of methanol was added for crystallization. The temperature of the crystallization mixture was lowered to 4 °C, the solid product was separated by centrifugation and dried to give 84.5 g of the photoinitiator 907 product with a GC purity of 98.7% and a yield of 60.57%. The final product was a yellow solid and its transmittance needed to be determined.

References

[1] Patent: CN108276361, 2018, A. Location in patent: Paragraph 0086; 0091; 0092; 0093