Methods for recovering and reusing selective homogeneous hydrogenation catalyst

A method for reusing a recovered selective homogeneous hydrogenation catalyst, comprising:

• a step of synthesizing cyclododecene by selectively hydrogenating a reaction solution containing cyclododecatriene, triphenylphosphine, formaldehyde, and ruthenium chloride, wherein a selective homogeneous hydrogenation catalyst is prepared from the triphenylphosphine, the formaldehyde, and the ruthenium chloride during the selective hydrogenation;
• a step of distilling and separating unreacted cyclododecatriene and cyclododecadiene, and the cyclododecene that is a product from the reaction solution in which the cyclododecene synthesis is completed;
• a step of recovering the selective homogeneous hydrogenation catalyst at a temperature of 10 to 30° C. and at a pressure of 0.1 bar or less in a nitrogen atmosphere;
• and
• a step of synthesizing cyclododecene by re-adding the recovered selective homogeneous hydrogenation catalyst to a reaction solution containing cyclododecatriene and secondarily selectively hydrogenating the reaction solution in which the recovered selective homogeneous hydrogenation catalyst was re-added,
• wherein a molar ratio of the ruthenium chloride:the triphenylphosphine:the formaldehyde is 1:100 to 300:150 to 500, and
• wherein the selective hydrogenations are performed in a stirred-tank reactor provided with a gas induction hollow stirrer.