Acid-, Water- and High-Temperature-Stable Ruthenium Complexes for the Total Catalytic Deoxygenation of Glycerol to Propane

The ruthenium aqua complexes [Ru(H2O)(2)(bipy)(2)](OTf)(2), [cis-Ru(6.6'-Cl-2-bipy)(2)(OH2)(2)](OTf)(2), [Ru-(H2O)(2)(phen)(2)](OTf)(2), [Ru(H2O)(3)(2,2':6',2-terpy)[(OTf)], and [Ru(H2O)(3)(Phterpy)](OTf)(2) (bipy-2,2'-bipyridinc: OTf=triflate: phen phenanthroline. terpy-terpyridine: Phterpy = 4'-phenyl-2,2':6'.2-terpri dine) arc water- and acid-stable catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOS(O)(2)(O)=CH, (triflic acid) as it dehydration co-catalyst they directly convert 1.2-hexane diol to n-hexanol and hexane. the tetpyridine complexes are stable and active its catalysts in temperatures >= 250 degrees and in either aqueous ssulfolane solution or pure water convert glycerol into n-propanol and ultilmately propane as the final reaction product ill tip to quantitative yield. For the terpy complexes the active catalyst Is postulated to be it carbonyl species [(4'-R-2,2' 6',2-terpy)Ru(CO)(H2O)(2)]-(OTF)(2), (R -H. Ph) formed by the decarbonylation of aldehydes (hexanal I'm. 1.2-hexanediol and 3-hydroxypropanal for glycerol) generated ill the reaction mixture through acid-catalyzed dehydration. The structure of the dimeric complex [[(4'-phenyl-2.2':6',2terpy)Ru(CO)}(2)(mu-OCH3)(2)](OTf)= has been determined by single crystal Xray crystallography (Space group PI (a = 8 2532(17): b= 12.858(3); c = 14.363(3),4: alpha=64.38(3), beta=77.26(3): gamma = 87 12(3)degrees. R=4.36%)