Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.35, No.2, 205-210, 1997
감열색소 중간체(2-methyl-4-methoxy aniline)의 제조
Synthesis of Functional Thermal Dye Intermediate(2-methyl-4-methoxy aniline)
감열색소 ODB-2(One Dye Black-2)의 중간체인 2-methyl-4-methoxy aniline을 산촉매 또는 염기성 촉매하에서 여러 종류의 벤젠고리 화합물로부터 1단계 반응으로 제조하였다. 황산촉매와 Pt/C 수소화촉매를 이용하여 ortho-nitrotoluene으로부터 80%의 수율로 생성물을 얻을 수 있었다. 반응은 Bamberger reaction mechanism을 따르고 있었으며 부산물은 완전 수소화가 진행된 ortho-toluidine이었다. 3-methyl-4-nitro phenol을 반응물로 이용할 경우 염기성촉매인 NaOH와 메틸기의 공급원인 DMSA(dimethyl sulfate) 그리고 수소화촉매가 이용되었으며 수소 압력하에서의 반응 율속단계는 anisole 형성을 위한 hydroxyl기의 alkylation 반응이었으며 최대 수율은 80%이었다. 그러나 이 경우 부산물인 4-amino-meta-cresol이 물세척에 의해서 반응 혼합물로부터 쉽게 분리되고 DMSA에 의한 메톡시화 반응에 의해 원하는 최종생성물로 전화가 가능하여 최초 반응물인 3-methyl-4-nitro phenol로부터 92%의 최종 수율을 얻을 수 있었다.
2-Methyl-4-methoxy aniline, an intermediate of the ODB-2 was synthesized from various aromatic compounds by using acid and base catalysts. With liquid sulfuric acid catalyst and Pt/C hydrogenation catalyst, an 80% yield was obtained from ortho-nitro toluene. The reaction followed the Bemberger reaction mechanism and the byproduct produced was toluidine resulted from a complete reduction of the reactant. To obtain 2-methyl-4-methoxy aniline from 3-methyl-4-nitro phenol, a one step reaction using NaOH and Pt/C hydrogenation catalysts was carried out under hydrogen pressure. The rate determining step was the alylation of the hydroxyl group in the phenol compound to form the corresponding anisole and the yield was 80%. In this route, however, the only byproduct formed, 3-methyl-4-amino phenol could be easily separated from the reaction mixture by washing with water and converted to the final desired product by a simple methoxylation with DMSA to give to an overall yield of 92%.
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