Patent ID: 7087797

Claim:
A hydroformylation process comprising: A) reacting an olefinically unsaturated compound comprising from 2 to 30 carbon atoms with carbon monoxide and hydrogen in the presence of a rhodium-bisphosphite complex catalyst to produce a mixture to be distilled comprising an aldehyde reaction product or products and a catalyst; B) reducing or eliminating the amount of dissolved and chemically bound molecular hydrogen in the mixture to be distilled; and C) separating the aldehyde product from the catalyst from the mixture to be distilled by means of distillation; wherein: D) said catalyst complex has at least a first and second state; E) said second state is more thermally stable and/or more stable against hydrolysis than the first state; F) reducing or eliminating the amount of hydrogen in the mixture to be distilled allows for most or all of the catalyst in the mixture to be in the more thermally and/or hydrolytic stable state, wherein reducing or eliminating the amount of hydrogen in the mixture to be distilled comprises adding an olefin to the mixture to be distilled.