Iridium is used in the following sectors of homogeneous catalysis:
Moreover, Heraeus manufactures new catalysts on a commercial scale and in strict confidence according to customers’ specifications.
Carbonylations are conversions with carbon monoxide (CO) under formation of aldehydes, ketones, or carboxylic acids by inserting a C=O group.
The most important process on a large scale is the carbonylation of methanol to acetic acid ("Monsanto Process"). Besides, there are other product routes, e.g. the manufacture of acetic anhydride from methyl acetate. All these processes are based on rhodium in the presence of iodine-containing compounds. Recent methods are also based on iridium with co-catalysts ("Cativa Process").
Hydrogenations are reactions of unsaturated molecules with hydrogen (H2). Precious metal compounds of rhodium, ruthenium, or iridium rank with the most effective homogeneous hydrogenation catalysts because of their outstanding selectivities.
Catalysts for hydrogenations are often equivalent to those for hydroformylations, where the reactants H2 and CO are applied.
Besides, C=O's, C=N's, and alkynes can be hydrogenated. Ruthenium in particular has an affinity for C=O bonds. Hydrogenations of imine groups could effectively be managed with iridium.
Hydrogenations lead to chiral centres in prochiral molecules. Like right and left hands, "chiral" molecules of the same constitution (empirical formula, structure) can coincide only with their mirror-images. Chirality is extraordinarily important to modern agents in the field of life science, where almost just one chiral variant is active to a specific purpose. Such "asymmetric hydrogenations" are feasible in a very effective way by using precious metal precursors along with chiral ligands. Heraeus offers a broad range of such precursors relevant to industry, mostly organometallics.