Abstract: A catalyst system including the combination of a source of tungsten; a ligand precursor containing at least N or O as a bonding atom to bond to the tungsten in the source of tungsten, the source of tungsten and the ligand precursor being selected to form an acid due to the bonding of the ligand precursor to the tungsten; and the catalyst system being characterized therein that it is substantially free of the acid formed due to the bonding of the ligand precursor to the tungsten; and that the molar ratio of the tungsten in the source of tungsten to ligand precursor is at least 1:3/n where n is the number of bonds that the ligand precursor forms with the tungsten.

Abstract: According to the present invention there is provided a metathesis reaction between at least two olefinic compounds which are the same or different, each olefinic compound comprising a non-cyclic olefin or a compound which includes a non-cyclic olefinic moiety. The metathesis reaction is carried out in the presence of a Grubbs first generation catalyst and is characterised therein that it is carried out in the presence of a phenolic compound in the form of a phenol or a substituted phenol, which substituted phenol includes at least one hydroxyl and at least one further moiety other than H and OH attached to an arene ring.

Abstract: A catalyst system capable of catalysing the carbonylation of an olefinally unsaturated compound is described. The 5 catalyst system is obtainable by combining: (a) a metal of Group VIB or Group VIII B or a compound thereof; and (b) a bidentate phosphine of general formula (I) Ad)s(CR4R5R6)TQ2-A-(K,D)Ar(E,Z)-B-Q1(Ad)u(CR1R2R3)v. Ad represents an optionally substituted adamantyl radical bonded to the phosphorous atom via any one of its tertiary carbon atoms. A method of production of the catalyst is also illustrated.