- Preparation method of ultraviolet absorber UV-571
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The invention relates to a preparation method of an ultraviolet absorber UV-571. The preparation method comprises the steps of putting UV-P, namely 2-(2'-hydroxyl-5'-methoxyphenyl) benzo triazole, and catalyst active carclazyte into a reaction vessel, supplying protective nitrogen after nitrogen replacement, heating up to melt materials, dropwise adding excessive dodecylene into a system in a constant speed after the temperature is stable, keeping the temperature for reaction after accomplishing dropwise addition, finishing the reaction till a content of the UV-P in a reaction liquid is less than 0.5%, filtering off a catalyst and performing reduced pressure distillation to remove the excessive dodecylene to form the UV-517. According to the method, a raw material conversion rate is high; the conversion rate of the UV-P can reach 99.5% or higher; olefin has low possibility of self-polymerization; side reactions are few; the product yield can reach 97.0%; the method is simple to operate; the catalyst can be separated from the reaction system via simple filtration, without the steps of neutralization, water washing and the like that easily generate waste water; the method is more environmentally friendly.
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Paragraph 0026; 0027; 0028
(2017/07/12)
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- Liquid 2-(2-hydroxy-3-higher branched alkyl-5-methyl-phenyl)-2H-benzotriazole mixtures, stabilized compositions and processes for preparing liquid mixtures
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Liquid 2-(2-hydroxy-3-higher branched alkyl-5-methylphenyl)-2H-benzotriazole mixtures are prepared by alkylating 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole with a straight chain alkene or with a branched chain alkene of 8 to 30 carbon atoms in the pres
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