Overview
Ultraviolet absorber is a kind of light stabilizer that can absorb the ultraviolet part of sunlight and fluorescent light sources without changing itself. Under sunlight and fluorescence, plastics and other polymer materials will undergo an auto-oxidation reaction due to the action of ultraviolet rays, leading to the degradation of the polymer and deterioration of appearance and mechanical properties. After adding ultraviolet absorbers, this high-energy ultraviolet ray can be selectively absorbed and turned into harmless energy for release or consumption. UV absorber BP-4 is a broad-spectrum UV absorber with high absorption efficiency, non-toxicity and no teratogenic side effects. It is a Class I sunscreen approved by the US FDA and is used frequently in the United States and Europe.
Purpose [1]
UV absorber BP-4 belongs to benzophenone compounds. It is a white or light yellow powder at room temperature, which can effectively absorb ultraviolet light of 285 ~ 325 Im. It is a kind of high absorption rate, non-toxic, non-photosensitizing, non-teratogenic, and stable to light and heat. A good broad-spectrum UV absorber, widely used in sunscreen creams, honeys, lotions, oils and other cosmetics. Sunscreen is generally applied to the surface of the skin and has a sunscreen effect to protect the skin.
UV absorber BP-4 has the advantages of good light and thermal stability and is widely used in sunscreen cosmetics such as sunscreen ointments, creams, honeys, lotions, and oils.
Product features and applications
UV absorber BP-4 is a benzophenone-based UV absorber, mainly targeting ultraviolet rays in the 280nm-360nm band.
UV absorber BP-4 is easily soluble in water, and the aqueous solution is acidic, so it needs to be neutralized during use. A solution pH greater than 9 will cause the absorption wavelength to narrow. It is mainly used in skin care products such as daily sunscreen to prevent skin aging caused by ultraviolet rays. It can also be used in water-based paints, dyes, and washing products.
Principle of synthesis [1]
This synthesis is developed in three steps:
The first step is the acylation reaction to synthesize 2, 4-dihydroxybenzophenone;
The second step is methylation of 2-hydroxy-4-methoxybenzophenone;
The third step is sulfonation to generate 2-hydroxy-4-methoxybenzophenone.
Production process [1]
Select the optimal reaction conditions for BP-1 in the first step of the synthesis reaction: the optimal reaction temperature is 50C; the ratio of resorcinol and trichlorotoluene is 1: 1.20; trichlorotoluene and trichlorotoluene The optimal molar ratio of aluminum chloride is 1: 1.3; catalytic synthesis method; use xylene extraction and water washing of kaolin to separate and obtain the crude product BP-1;
The optimal conditions for the acylation reaction in the second step of the synthesis reaction: n (2,4-dihydroxybenzophenone) : v (acetone) =1:200; n (K2C03) :n (bp- 1) = 0.6; n (dimethyl sulfate) / n (2,4-dihydroxybenzophenone) = 1 and without adding any catalyst, collect acetone by distillation to obtain impurities bp-1 and dimethyl sulfate. crude product;
The optimal conditions for the sulfonation reaction in the third step of the synthesis reaction: the mass ratio of the acylation product to concentrated sulfuric acid is 1:10; the sulfonation temperature is 70°C; the reaction time is 2 h and both Hanwha acrylic resins The solvent in the centrifugal separation step is methanol, and the drying and packaging of the product should be strictly carried out in a clean room.
Reference materials
[1] Design of synthesis process of UV absorber BP-4, College of Arts and Sciences, Applied Chemistry, Xu Ying;
