tion of hydroformylation process parameters would be highly desirable to the art. 

It has been discovered that deactivation of metal› organopolyphosphite ligand complex catalysts caused by an inhibiting or poisoning organomonophosphite can be reversed or at least minimized by carrying out hydroformy› lation processes in a reaction region where carbon monoxide partial pressure is sufficiently high that the hydroformylation reaction rate is of a negative or inverse order in carbon monoxide and which is sufficient to prevent and/or lessen deactivation of $_{the }$metal-organopolyphosphite ligand com› plex catalyst and at a temperature such that the temperature difference between reaction product fluid temperature and inlet coolant temperature is sufficient to prevent and/or lessen cycling of carbon monoxide partial pressure, hydro› gen partial pressure. total reaction pressure, hydroformyla› tion reaction rate and/or temperature during said hydro- formylation process. 

This invention relates in part to a process which com› prises reacting one or more reactants in the presence of a metal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more products, wherein said process is conducted at (a) a carbon monoxide partial pressure such that reaction rate increases as carbon monoxide partial pressure decreases and reaction rate decreases as carbon monoxide partial pressure increases and which is sufficient to prevent and/or lessen deactivation of $_{the }$metal-organopolyphosphite ligand complex catalyst and (b) a temperature such that the temperature difference between reaction product fluid temperature and inlet coolant temperature is sufficient to prevent and/or lessen cycling of carbon monoxide partial pressure. hydrogen partial pressure, total reaction pressure. reaction rate and/or temperature during said process. 

This invention also relates in part to a hydroformylation process which comprises reacting one or more olefinic unsaturated compounds with carbon monoxide and hydro› gen in the presence of $_{a }$metal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more aldehydes. wherein said hydroformylation process is conducted at (a) a carbon monoxide partial pressure such that hydroformylation reaction rate increases as carbon monoxide partial pressure decreases and hydroformylation reaction rate decreases as carbon monoxide partial pressure increases and which is sufficient to prevent and/or lessen deactivation of $_{the }$metal-organopolyphosphite ligand com› plex catalyst and (b) a temperature such that the temperature difference between reaction product fluid temperature and inlet coolant temperature is sufficient to prevent and/or lessen cycling of carbon monoxide partial pressure. hydro- gen partial pressure. total reaction pressure. hydroformyla› tion reaction rate and/or temperature during said hydro› formylation process. 

## DISCLOSURE OF THE INVENTION 

This invention further relates in part to an improved hydroformylation process which comprises (i) reacting in at least one reaction zone one or more olefinic unsaturated compounds with carbon monoxide and hydrogen in the presence of a metal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more aldehydes and (ii) separating in at least one separation zone or in said at least one reaction zone the one or more 

aldehydes from said reaction product fluid, the improvement comprising preventing and/or lessening deactivation of the metal-organopolyphosphite ligand complex catalyst and preventing and/or lessening cycling of carbon monoxide partial pressure, hydrogen partial pressure. total reaction pressure. hydroformylation reaction rate and/or temperature during said hydroformylation process by conducting said hydroformylation process at (a) a carbon monoxide partial pressure such that hydroformylation reaction rate increases as carbon monoxide partial pressure decreases and hydro› formylation reaction rate decreases as carbon monoxide partial pressure increases and (b) a temperature such that the temperature difference between reaction product fluid tem› perature and inlet coolant temperature is less than about 25° c. relates in part to a hydroformy› 

This invention yet further lation process which comprises reacting one or more olefinic unsaturated compounds with carbon monoxide and hydro› gen in the presence of $_{a }$rnetal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more aldehydes. wherein said hydroformylation process is conducted at a carbon monoxide partial pressure such that hydroformylation reaction rate increases as carbon monox› ide partial pressure decreases and hydroformylation reaction rate decreases as carbon monoxide partial pressure increases and which is sufficient to prevent and/or lessen deactivation of $_{the }$metal-organopolyphosphite ligand complex catalyst. 

This invention also relates in part to an improved hydro› f ormylation process which comprises (i) reacting in at least one reaction zone one or more olefinic unsaturated com› pounds with carbon monoxide and hydrogen in the presence of $_{a }$metal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more aldehydes and (ii) separating in at least one separation zone or in said at least one reaction zone the one or more aldehydes from said reaction product fluid, wherein said reaction product fluid contains at least some organomonophosphite ligand formed during said hydroformylation process, the improvement comprising conducting said hydroformylation process at (a) a carbon monoxide partial pressure such that hydroformy› lation reaction rate increases as carbon monoxide partial pressure decreases and hydroformylation reaction rate decreases as carbon monoxide partial pressure increases and which is sufficient to prevent and/or lessen coordination of the organomonophosphite ligand with said metal› organopolyphosphite ligand complex catalyst and (b) a temperature such that the temperature difference between reaction product fluid temperature and inlet coolant tem› perature is sufficient to prevent and/or lessen cycling of carbon monoxide partial pressure. hydrogen partial pressure. total reaction pressure. hydroformylation reaction rate and/ or temperature during said hydrofonnylation process. 

This invention further relates in part to an improved hydroformylation process which comprises (i) reacting in at least one reaction zone one or more olefinic unsaturated compounds with carbon monoxide and hydrogen in the presence of a metal-organopolyphosphite ligand complex catalyst and optionally free organopolyphosphite ligand to produce a reaction product fluid comprising one or more aldehydes and (ii) separating in at least one separation zone or in said at least one reaction zone the one or more aldehydes from said reaction product fluid. wherein said reaction product fluid contains at least some organomono› phosphite ligand formed during said hydroformylation process. the improvement comprising preventing and/or 

