Name | ultraviolet absorbent UV-531 |
Synonyms | UV Absorber UV-531 2-hydroxy-4-octyloxy benzophenone BP-12 octabenzone chimassorb81 |
CAS | 1843-05-06 |
Molar Mass | 326.43 |
Melting Point | 47~49 |
Physical and Chemical Properties | White or slightly yellow crystalline powder or thin sheet, density 1.16g/cm3, boiling point 457.9 ℃ (1 atm). Good solubility, low mobility, not decomposed by acids or bases, and precipitation occurs when acid is added. It can combine with iron and heavy metal ions to form salts. Easily soluble in organic solvents, slightly soluble in ethanol and methanol, insoluble in water. |
Use | This product is a representative of benzophenone type UV absorbers, capable of absorbing UV rays ranging from 240 to 340nm. It has strong adsorption ability on cotton fibers and can be used as a UV resistant finishing agent for cotton fabrics. It can delay the yellowing of polymers and block the loss of physical properties. |
This product is non-toxic and has slight irritation to the skin and eyes. Store in a sealed and dry place away from light.
1. Synthesis of 2,4-dihydroxybenzophenone
Add a certain amount of resorcinol and a small amount of water into the reaction kettle, stir to dissolve, add an equal amount of benzotrichloromethane and ethanol, stir and slowly raise the temperature to 40 ℃ for reaction, and generate 2,4-dihydroxybenzophenone precipitation. After the reaction is complete, filter and wash the filter cake with a dilute NaHCO3 solution before reuse. Wash with clean water, filter dry, and set aside for use.
2. Synthesis of Chlorooctane
Add an equal amount of n-octanol and concentrated hydrochloric acid (37%) to the acid-resistant reactor, use a small amount of anhydrous zinc chloride as a catalyst, stir and react for 6-10 hours, then let it stand and separate the water layer. Wash the oil layer with a dilute NaHCO3 aqueous solution, and then wash with water. Perform vacuum fractionation of the product, remove water and low boiling substances, and collect chlorooctane for use.
3. Synthesis of 2-hydroxy-4-n-octyloxybenzophenone
In a stirring reactor, the previously prepared 2,4-dihydroxybenzophenone and an equal amount of cyclohexanone are added. After stirring and dissolving, the prepared chlorooctane, an appropriate amount of soda ash, and potassium iodide are added. Heat up and maintain reflux for about 10 hours, evaporate cyclohexanone, transfer the solution to a crystallization tank for cooling, crystallization, and filtration to obtain crude 2-hydroxy-4-n-octyloxybenzophenone. Recycle cyclohexanone and filtrate.
4. Product Refinement
Dissolve the crude product in ethanol, heat and decolorize it with activated carbon for about 30 minutes, filter while it is hot, evaporate and concentrate the filtrate, cool and crystallize it, and filter and dry it to obtain the final product.