Ruthenium-containing catalyst composition for olefin metathesis

A ruthenium-containing olefin metathesis catalyst system comprising a reaction product of a ruthenium compound (A), a phosphorus compound (B), and a compound (C) containing a carbon-to-carbon triple bond, in the presence of an olefin to be metathesized and hydrogen, wherein mole ratios of compounds A:B:C are in the range of about 1.0:0.01-100:0.01-100,

• wherein hydrogen is present as a catalyst system activator at a partial pressure of hydrogen of from 1.times.10.sup.-2 mm to about 200 atmospheres;
• wherein said ruthenium compound (A) is selected from the group consisting of [RuX.sub.2 (arene)].sub.2, RuX.sub.2 (arene)(PRR.sup.1 R.sup.2), RuX.sub.2 (arene)(PHRR.sup.1), RuX.sub.2 (arene)(PH.sub.2 R), RuX.sub.2 (arene)[P(OR)(OR.sup.1)(OR.sup.2)], RuX.sub.3, RuX.sub.3 -hydrate, RuX.sub.2 (PRR.sup.1 R.sup.2).sub.3, RuX.sub.2 (PHRR.sup.1).sub.3, RuX.sub.2 (PH.sub.2 R).sub.3, RuX.sub.2 [P(OR)(OR.sup.1)(OR.sup.2)].sub.3, RuX.sub.2 (PRR.sup.1 R.sup.2).sub.4, RuX.sub.2 (PHRR.sup.1).sub.4, RuX.sub.2 (PH.sub.2 R).sub.4, and RuX.sub.2 [P(OR)(OR.sup.1)(OR.sup.2)].sub.4, wherein P is phosphorus, and wherein R, R.sup.1 and R.sup.2 are the same or different and are each selected from the group consisting of unsubstituted and substituted alkyl, cycloalkyl, aryl and arylalkyl groups of up to about 20 carbon atoms;
• and
• wherein (X) comprises an aliphatic or aromatic anionic ligand containing up to 20 carbon atoms or halogen, nitrate, nitrite, hydroxide or alkoxide having the formula OR.sup.3 and wherein R.sup.3 is selected from the group consisting of alkyl, cycloalkyl, aryl, and alkylaryl groups of up to 20 carbon atoms and wherein the arene ligand is selected from the group consisting of an unsubstituted aromatic ligand, a substituted aromatic ligand and mixtures thereof;
• provided that said phosphorus compound (B) is optional if said ruthenium compound (A) contains said optional phosphorus compound as a ligand.