Korea Kumho Petrochemical Co., Ltd.

Young J Joo

Jeong-Im Won

Jin-Eok Kim

Kum-Ui Hwang

Jin Eok Kim

Jeong Im Won

Chang-Min Kim

Kum Ui Hwang

Tae Yi Kang

Kwang-Chun Park

Disclosed is a synthesis method of cyclohexyl phenyl ketone with a high selectivity and a high yield from 1,3-butadiene and acrylic acid in the presence or absence of benzene or a non-aromatic organic solvent in the same reaction without a step of separating or purifying intermediates, the synthesis method including sequentially carrying out a [2+4] Diels-Alder reaction, a hydrogenation reaction, a chlorination reaction and a Friedel-Crafts reaction in the presence/absence of benzene or a non-aromatic organic solvent without separation of intermediates.

Method for preparing cyclohexyl phenyl ketone from 1,3-butadiene and acrylic acid

A disclosed method of preparing p-phenylenediamine includes the steps of: reacting urea and nitrobenzene with a base in the presence of a polar solvent to yield 4-nitrosoaniline and 4-nitroaniline; and subsequently, diluting the resulting mixed solution in an alcohol and performing hydrogenation using a catalyst, thereby providing highly pure p-phenylenediamine destitute of an ortho- or meta-isomer as a byproduct. The method has some advantages in that: the process is simplified in such a manner that the hydrogenation is performed in the presence of the hydrogenation catalyst in a single reactor (i.e., one pot) without a need of isolating 4-nitrosoaniline or purifying the product; inexpensive urea and an alkali base are used to reduce the production cost; and 4-nitrosoaniline is formed as an intermediate to yield p-phenylenediamine with a high selectivity, thereby requiring no purification process after isolation of the product.

Method of preparing p-phenylenediamine

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

This invention relates to a process for preparing 4-nitrodiphenylamine and 4-nitrosodiphenylamine to be used for 4-aminodiphenylamine as an intermediate of antiozonant, wherein carbanilide is reacted with nitrobenzene in the presence of an appropriate base, while simultaneously adding aniline to the mixture so as to regenerate some amounts of carbanilide as a starting material. According to this invention, 4-nitrodiphenylamine and 4-nitrosodiphenylamine can be prepared in a higher selectivity and conversion rate via a continuous reaction by recycling carbanilide, a starting material, while adding a certain amount of aniline during the process. Further, the amount of waste water can be significantly reduced compared to the conventional method without any corrosive materials harmful to the environment.

Method for preparing 4-nitrodiphenylamine and 4-nitrosodiphenylamine

Method for preparing ethylbenzene from 4-vinylcyclohexene

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

Young J Joo