Process for producing adamantane

#The present invention relates to a process for producing adamantane (tricyclodecane[3.3.1.13,7]) by isomerization reaction of tetrahydrodicyclopentadiene (tricyclodecane[5.2.1.02,6]) with a HF.BF3 catalyst. Adamantane is a very useful raw material for producing an adamantane derivative and is applied to specialty chemical and fine chemical fields including a druggery, special fuel, a lubricant, an engineering polymer, a functional polymer, an agrichemical and a surfactant.

#Generally, adamantane is obtained by isomerization of tetrahydrodicyclopentadiene. Conventionally, as a catalyst used for producing adamantane, there are known aluminum halide type catalysts, alumina type catalysts, zeolite type catalysts and superacid catalysts.

#When the aluminum halide type catalyst such as AlCl3-HCl, AlBr3-t-BuBr, AlCl3-t-BuCl is used, the amount of the catalyst based on a raw material is required to increase. Further, a byproduct compound formed by the reaction is apt to form a strong complex with the catalyst. Therefore, defects are that an activity decreases immediately and that the renewal of the catalyst is difficult. Journal of Brennst-Chem. 1961, 42, 90, describes a method in which a reaction is carried out by using HCl-AlCl3 catalyst under high hydrogen pressure. In this system, high pressure hydrogen is required and many problems are found with regard to the recovering method of a catalyst.

#The present invention will be explained more in detail with reference to Examples hereinafter, while the present invention shall not be limited to the following Examples.

#18 g of tetrahydrodicyclopentadiene, 0.15 g of 5 wt % platinum/activated carbon, and 80 g of HF were placed in a 300 ml-autoclave equipped with a magnetic stirrer, a baffle plate, a gas-introducing opening and a liquor-feeding opening and made of Hastelloy, and 23 g of BF3 was introduced to the autoclave. Then, hydrogen was introduced to the autoclave so as to achieve a partial pressure of 1.5 Mpa, the contents in the autoclave was heated by feeding hot water to the outside (jacket) of the autoclave with stirring, and the liquid temperature in the autoclave was increased up to 50° C. with stirring. After 45 minutes from the reaching of the liquid temperature to 50° C., the stirring was terminated and the contents in the autoclave were allowed to stand to complete the reaction. After the completion of the reaction, the reaction liquor was drawn from the bottom of the reactor and diluted with water. An organic substance in the catalyst layer was extracted with hexane and analyzed by a gas chromatography. The conversion rate of tetrahydrodicyclopentadiene was 87.3%. The adamantane selection rate was 88.2%.

#Example 1 was repeated except that the 5 wt % platinum/activated carbon was replaced with 5 wt % palladium/activated carbon. The conversion rate of tetrahydrodicyclopentadiene was 89.7%. The adamantane selection rate was 83.6%.