Supercritical hydrogenation

A process for achieving selective hydrogenation of one or more functional groups in an organic compound substrate to produce a selected hydrogenation product, wherein the substrate is an organic compound being, or having a group in its molecule, selected from:

• alkene, cyclic alkene and cyclic alkane, lactone, anhydride, amide, lactam, Schiffs base, aldehyde, ketone, alcohol, nitro, hydroxylamine, nitrile, oxime, imine, azine, hydrazone, aniline, azide, cyanate, isocyanate, thiocyanate, isothiocyanate, diazonium, azo, nitroso, phenol, ether, furan, epoxide, hydroperoxide, peroxide, ozonide, arene, saturated or unsaturated heterocycle, halide, acid halide, acetal, ketal, and a selenium or sulfur containing compound, wherein the process comprises:
• continuously supplying, in a preliminary stage, the compound to a heterogeneous catalyst to pass thereover and be removed from the catalyst in a continuous flow procedure with at least one component, in addition to hydrogen, being under supercritical or under near-critical conditions, near-critical conditions being conditions below supercritical at which density of a fluid is sufficient to ensure that reactants are substantially in a single phase,
• varying one or more of temperature, pressure, flow rates and hydrogen concentration that, for the catalyst, define a set of conditions, to obtain hydrogenation products differing as to identity and/or proportions of different reaction products in accordance with a prevailing set of conditions, and
• subsequently applying a selected set of conditions to obtain only a selected hydrogenation product in accordance with the selected set of conditions.