Abstract: A process for the production of a carboxylic acid by carbonylation of an alkyl alcohol or its reactive derivative comprises contacting the reactant with carbon monoxide in a liquid reaction composition comprising: (a) an iridium catalyst or rhodium catalyst, (b) alkyl halide, (c) at least a finite concentration of water and (d) rhenium as promoter.

Abstract: A ruthenium-phosphine complex represented by formula (I): ##STR1## wherein R.sup.2 -BINAP represents a teritary phosphine compound represented by formula (II): ##STR2## wherein R.sup.2 represents a hydrogen atom, a methyl group, a methoxy group, or a t-butyl group; X represents a halogen atom; and R and R.sup.1, which may be the same or different, each represent a phenyl group or a substituted phenyl group, and a ruthenium-phosphine complex represented by formula (III): ##STR3## wherein R and R.sup.1 are as defined above; and dma represents N,N-dimethylacetamide, which is an intermediate for synthesizing the ruthenium-phosphine complex of formula (I), are disclosed. The complex of formula (I) is useful as a catalyst for general syntheses with its ligand being an optically inactive compound or for asymmetric syntheses with its ligand being an optically active compound and, also, can be prepared at a low cost.