Synthesis of Adamantane with the Modified Molecular Sieves Catalysts

Adamantane was synthesized by the batch reactor system in the presence of hydrogen using endo-tetrahydrodicyclopentadiene(endo-TCD) as reactant,solid super-acid ZrO_2-SO~(2-)_4(SZ) loaded REY,USY,Si-MCM-41molecular sieves as isomerizing catalysts.Loading ZrO_2-SO~(2-)_4 on surface of molecular sieve was helpful to increase the yield of adamantane.The effects of reaction temperature,hydrogen pressure,the content of the surface loaded ZrO_2 and the types of molecular sieves on synthesis of adamantane were investigated respectively.The results show that higher temperature(270 ℃) will increase the yield of hydrocracking(by-products) which led to the decrease of adamantane yield.The highest yield of adamantane(22.77%) was obtained by using(SZ(20%))/REY as isomerizing catalyst under the following conditions: catalyst/reactant(m/m) is 0.625,reaction temperature is 250 ℃,hydrogen pressure is 1.5 MPa,reaction time is 3 h.The total selectivity of adamantane and exo-TCD was as high as 95%.