Korea Kumho Petrochemical Co., Ltd.

Kum-Ui Hwang

Jin-Eok Kim

Young J Joo

Jeong-Im Won

A method for preparing 4-nitrosoaniline, including reacting urea and nitrobenzene in a polar organic solvent in the presence of a base at a temperature of room temperature to 150&deg; C. The method uses a relatively cheap urea and nitrobenzene as the raw materials, and also a relatively cheap base, thereby decreasing the manufacturing cost. Urea used as an amine donor is excellent in a reactivity to nitrobenzene, and a reaction intermediate is unstable as compared with 4-(4-nitrophenyl)benzamide to easily decompose into 4-nitroaniline and 4-nitrosoaniline. This allows a reaction time and a process time to be shortened. Moreover, the method is advantageous in that waste hazardous to the environment is not produced as a byproduct.

Manufacturing method for 4-nitrosoaniline from urea and nitrobenzene

A method for preparing 4,4'-dinitrodiphenylamine, including reacting urea and nitrobenzene in a polar organic solvent in the presence of a base at a temperature of room temperature to 100.degree. C. The method employs a relatively cheap urea and nitrobenzene as the raw materials, and also employs a relatively cheap base, thereby decreasing the manufacturing costs. Moreover, the method does not produce by-products, thus eliminating a need for a post-treating process. Additionally, the method is advantageous in that the production of 4,4'-dinitrodiphenylamine can be achieved in high yield and selectivity even under non-intensive reaction conditions by appropriately controlling the amounts of urea and nitrobenzene.

Preparation of 4,4'-dinitrodiphenylamine from urea and nitrobenzene

A method for preparing 2-methyl-1,4-naphthoquinone (vitamin K.sub.3), in which 2-methyl-1,4-benzoquinone and 1,3-butadienes are subjected to a �2+4! Diels-Alder reaction and subsequently to oxidative dehydrogenation, using dimethylsulfoxide as both a dehydrogenating agent and a solvent in the presence of at least one Lewis acid or a Broensted acid, in a single pot, shows high selectivity and yield.

Method for preparing 2-methyl-1,4-naphthoquinone (vitamin K.sub.3)

A method for preparing anthraquinones, by which 1,4-benzoquinone or 1,4-naphthoquinone and 1,3-butadienes are subjected to a �2+4! Diels-Alder reaction and subsequently to oxidative dehydrogenation by using dimethylsulfoxide as a dehydrogenating agent in a single pot in the presence of a Lewis acid or Broensted acid shows high selectivity and yield.

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Taejeon, South Korea

Kum-Ui Hwang