| 摘要 |
<p>The invention relates to a process for the production of hexahydro-iso-alpha-acids starting from iso-alpha-acids (or tetrahydro-iso-alpha-acids) in which iso-alpha-acids (or tetrahydro- iso-alpha-acids) are mixed with a heterogeneous ruthenium containing catalyst, that catalyzes the hydrogenation from iso-alpha-acids or tetrahydro-iso-alpha-acids to hexahydro- iso-alpha-acids, either in solvent-free conditions, or in the presence of a solvent phase (e.g. carbon dioxide, water, ethanol or another organic solvent, or mixtures thereof), and in the absence or presence of other hop compounds (such as beta-acids). The resulting mixture is then subjected to a temperature at which the iso-alpha-acid (or tetrahydro-iso-alpha-acid) containing reaction medium is sufficiently low in viscosity to allow easy mixing with the heterogeneous ruthenium containing catalyst and held under a hydrogen containing atmosphere (either pure hydrogen gas or mixed with an inert gas) for a reaction time sufficient to effect high conversion of the iso-alpha-acid (or tetrahydro-iso-alpha-acid) reactant into the hexahydro-iso-alpha-acid product. The molar ratio of iso-alpha-acid or tetrahydro-iso-alpha-acid to ruthenium varies between 1:1 and 2000:1. After the hydrogenation process, the heterogeneous ruthenium containing catalyst can be separated from the hexahydro-iso-alpha-acid product phase by centrifugation, filtration, decantation or other liquid-solid separation techniques. The hydrogenation process can be performed batch-wise or alternatively in continuous mode.</p> |
