Preparation method of n,n'-bis(4-ethoxycarbonylphenyl)-n'-benzylformamidine

Abstract

The invention discloses an N, N'-(4-ethyoxyl carbonyl phenyl)-N'-benzyl formamidine preparation method, and belongs to the technical field of benzyl formamidine compound preparation, wherein N, N'-(4-ethyoxyl carbonyl phenyl)-N'-benzyl formamidine is mainly used for an ultraviolet light absorber. According to the N, N'-(4-ethyoxyl carbonyl phenyl)-N'-benzyl formamidine preparation method, ethyl p-aminobenzoate is used as the raw material, and the ethyl p-aminobenzoate is subjected to a synthetic route including formylation, condensation and N-alkylation to prepare the N, N'-(4-ethyoxyl carbonyl phenyl)-N'-benzyl formamidine product. The N, N'-(4-ethyoxyl carbonyl phenyl)-N'-benzyl formamidine preparation method has the remarkable advantages that the time for the overall reaction process is shortened, the total yield is increased, the cost is reduced because filtrate in an aftertreatment process of the formylation reaction and the condensation reaction can be recycled and reused, the yield of final products can be stabilized between 65% and 70%, and the preparation method is beneficial to industrial production.

Description

Technical field: [0001] The invention belongs to the technical field of preparation of benzylformamidine compounds, and in particular relates to a preparation method of N,N'-(4-ethoxycarbonylphenyl)-N'-benzylformamidine as ultraviolet absorbers. Background technique: [0002] In 1949, Royston M.Roberts reported the synthesis method of aryl formamidine compounds using triethyl orthoformate and aromatic amines as raw materials (J.Am.Chem.Soc., 1949,71,3848), after which Joseph A. Virgilio et al reported in 1977 that formamidine compounds can be used as UV absorbers (US4021471), and it has been confirmed that formamidine UV absorbers are a class of efficient and widely used UV absorbers, such as N-(4- Ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine has good compatibility with organic macromolecules and good light stability, and can be widely used in polyurethane, adhesives, foams and other polymer materials, and N,N'-(4-ethoxycarbonylphenyl)-N'-benzylformamidine has N-(4-...

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Problems solved by technology

Patent US4021471 has also reported the preparation method of this formamidine ultraviolet absorber at the same time, promptly take p-aminobenzoic acid ethyl ester and trialkyl orthoformate as raw material, make intermediate imide ester, then with N-alkane But this method prepares the route of reaction raw material N-alkylaniline to be longer, has obviously increased synthetic cost, is unfavorable for suitability for industrialized production

In 2005, Byung-il Choi improved the synthetic route of JosephA.Virgilio and synthesized N,N'- (4-Ethoxycarbonylphenyl)-N'-benzylformamidine (WO115973A1), although this process shortens the synthetic route, but uses benzyl bromide as the benzylation reagent, not only the synthetic cost is increased, but also the The total reaction yield of the synthetic route is only 37.8%

Patent CN101481331A disclosed that benzyl chloride was used instead of benzyl bromide as benzylation reagent, which reduced the production cost, although aprotic dipolar solvent was used in the N-alkylation reaction, and sodium carbonate, potassium carbonate, sodium hydride etc. as alkali, instead of the traditional water / toluene two-phase reaction system using sodium hydroxide as alkali and tert-butylammonium bromide as phase transfer catalyst, but the yield of the final product has not been greatly improved

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