Method for preparing ultraviolet light absorber UVT-150

Abstract

The invention discloses a method for preparing an ultraviolet light absorber UVT-150. The method is composed of the following process steps: (1) carrying out an aryl amination reaction, namely adding methyl p-aminobenzoate and an organic solvent into a reactor, heating, slowly dripping cyanuric chloride, maintaining the temperature and reacting, distilling, and crystallizing so as to obtain an intermediate methyl triazone; and (2) carrying out an ester exchange reaction, namely adding methylbenzene, a catalyst and isooctyl alcohol into the reactor, heating, dripping a toluene solution of the methyl triazone, maintaining the temperature and reacting, distilling, and crystallizing thereby obtaining the product, namely the ultraviolet light absorber UVT-150. The method disclosed by the invention is simple in process route, readily available in raw materials, convenient to operate and high in yield, and the industrialized production is easily realized.

Description

technical field [0001] The invention relates to a synthesis method of an ultraviolet absorber, in particular to a preparation method of an ultraviolet absorber UVT-150. Background technique [0002] UVT-150 (also known as octyl triazone) is a triazine ultraviolet absorber, which has a special absorption function for the UVB (275-320 nm) band, and its chemical name is 4,4',4''-( Tris(2-ethylhexyl) 1,3,5-triazine-2,4,6-triimino)tribenzoate, high photostability and protection against UV-B-induced immunosuppression, water resistance Strong, has good affinity to the keratin protein of the skin. It has the advantages of high absorption rate and low dosage. Generally, only a very small dosage is needed in sunscreen care products to achieve high SPF value and excellent waterproof effect. [0003] Currently domestic and foreign reports about 4,4',4''-(1,3,5-triazine-2,4,6-triimino)tribenzoic acid tris(2-ethylhexyl)ester (UVT-150) The synthesis method mainly contains following two ...

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Problems solved by technology

[0008] The problem of the above-mentioned method one is that in the substitution reaction of melamine and p-chlorobenzoic acid, it is difficult to replace the chlorine substituent on the benzene ring with the amino group in melamine, so that the yield is difficult to improve; while intermediate 2,4,6- The yield of tris[(p-carboxyphenyl)amino]-1,3,5-triazine and isooctyl alcohol is not high, so the industrial cost of this process is relatively high

[0009] The problem of the above-mentioned method two is that the ultraviolet absorber UVT-150 product is prepared by directly using isooctyl aminobenzoate as a raw material and cyanuric chloride for substitution reaction, but since the raw material of isooctyl aminobenzoate is not produced domestically, the imported raw It is quite expensive, so all manufacturers of UVT-150 first prepare isooctyl p-nitrobenzoate by esterification reaction between p-nitrobenzoic acid and isooctyl alcohol, and then carry out catalytic hydrogenation to obtain isooctyl p-aminobenzoate , because the catalytic hydrogenation process needs to be carried out under high pressure, the construction of a catalytic hydrogenation workshop requires a large investment, high safety production requirements, and high risks. Generally, enterprises are unwilling to build it themselves; and the wastewater pollution of the iron powder reduction process is serious; Benzoic acid and iso-octanol undergo esterification to prepare p-aminobenzoic acid isooctyl alcohol, but this esterification reaction is difficult to carry out, the yield is not high, and the overall cost is higher

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