Catalytic hydrogenation of 2-ethyl-9,10-anthrahydroquinone

Catalytic hydrogenation of the solution of 2-ethyl-9,10-anthrahydroquinone (EAHQ) using suspended palladium catalyst at a temperature of 60 °C and atmospheric pressure was studied. The solvent system consisted of a mixture of polar and non-polar solvents. Shellsol AB (SHAB) (a mixture of alkylated aromatic hydrocarbons C9 through to C11) was always used as the non-polar component of the solvent systems. 2-Ethylhexane-1-ol (EHOL), 2,6-dimethylheptane-4-ol (DIBC) and N,N,N′,N′-tetra-n-butylurea (TBU) were polar components of the solvent system. The resulting reaction scheme of deep hydrogenation of 2-ethyl-9,10-anthrahydroquinone at given conditions differs from the previously published schemes in the aspect that hydrogenation of 2-ethyl-5,6,7,8-tetrahydro-9,10-anthrahydroquinone that leads to the formation of 2-ethyl-1,2,3,4,5,6,7,8-octahydro-9,10-anthrahydroquinone does not take place in any significant extent, and furthermore, 2-ethyl-5,6,7,8-tetrahydro-9-anthrone and 2-ethyl-5,6,7,8-tetrahydro-10-anthrone are formed by hydrogenation of the aromatic core of 2-ethyl-9-anthrone or 2-ethyl-10-anthrone.