Hydroformylation process and bisphosphite compound used therein

A hydroformylation process for preparing a hydroformylated product by reacting an olefinic compound selected from the group consisting of an olefinic compound substituted with a saturated hydrocarbon group only, an olefinic compound substituted with a hydrocarbon group containing an unsaturated hydrocarbon group and an olefinic compound substituted with a functional group containing a heteroatom with hydrogen and carbon monoxide in the presence of a Group VIII metal catalyst which provides a concentration of Group VIII metal compound in the hydroformylation reaction medium of from 0.05 mg to 5 g per liter of the olefinic compound, on the basis of the Group VIII metal atom, at a temperature ranging from room temperature to 200.degree. C. and a pressure ranging from atmospheric pressure to 200 atmospheres, said reaction medium containing a phosphite compound in an amount of from 0.5 to 500 mol per gram of the Group VIII metal atom and having the formula (I), ##STR18## wherein R.sup.1 and R.sup.2 are each an aromatic hydrocarbon group which may be the same or different and the aromatic hydrocarbon group has at least a hydrocarbon group on a carbon atom adjacent to a carbon atom bonded to an oxygen atom as a substituent;

• A.sup.1 is an n-valent organic group having an aliphatic hydrocarbon group, a cycloaliphatic hydrocarbon group or an aromatic hydrocarbon group bonded to an adjacent oxygen atom;
• each of which may have a substituent;
• n is an integer of from 2 to 4;
• and each ##STR19## group may be the same or different.