It is well known in the art that aldehydes may be readily produced by reacting an olefinically unsaturated compound with carbon monoxide and hydrogen in the presence of a rhodium-organophosphite ligand complex catalyst and that preferred processes involve continuous hydroformylation and recycling of the catalyst solution such as disclosed, for example, in U.S. Pat. Nos. 4,148.830; 4,717,775 and 4,769, 498. Such aldehydes have a wide range of known utility and are useful, for example, as intermediates for hydrogenation to aliphatic alcohols. for aldol condensation to produce plasticizers, and for oxidation to produce aliphatic acids. 

However. notwithstanding the benefits attendant with such rhodium-organophosphite ligand complex catalyzed liquid recycle hydroformylation processes. stabilization of the catalyst and organophosphite ligand remains a primary concern of the art. Obviously catalyst stability is a key issue in the employment of any catalyst. Loss of catalyst or catalytic activity due to undesirable reactions of the highly expensive rhodium catalysts can be detrimental to the pro› duction of the desired aldehyde. Likewise degradation of the organophosphite ligand employed during the hydrofonny› lation process can lead to poisoning organophosphite com› pounds• or inhibitors or acidic byproducts that can lower the catalytic activity of the rhodium catalyst. Moreover, pro› duction costs of the aldehyde product obviously increase when productivity of the catalyst decreases. 

Numerous methods have been proposed to maintain cata› lyst and/or organophosphite ligand stability. For instance, U.S. Pat. No. 5.288.918 suggests employing a catalytic activity enhancing additive such as water and/or a weakly acidic compound; U.S. Pat. No. 5.364.950 suggests adding an epoxide to stabilize the organophosphite ligand; and U.S. Pat. No. 4,774.361 suggests carrying out the vaporization separation employed to recover the aldehyde product from the catalyst in the presence of an organic polymer containing polar functional groups selected from the class consisting of amide, ketone, carbamate, urea, and carbonate radicals in order to prevent and/or lessen rhodium precipitation from solution as rhodium metal or in the form of clusters of rhodium. Notwithstanding the value of the teachings of said references, the search for alternative methods and hopefully an even better and more efficient means for stabilizing the rhodium catalyst and organophosphite ligand employed remains an ongoing activity in the art. 

For instance, a major cause of organophosphite ligand degradation and catalyst deactivation of rhodium› organophosphite ligand complex catalyzed hydrofonnyla- tion processes is due to the hydrolytic instability of the organophosphite ligands. All organophosphites are suscep- 

# HYDROFORMYLATION PROCESSES 

This application claims the benefit of provisional U.S. patent application Ser. Nos. 60/008289, 60/008763. 60/008284 and 60/008286. all filed Dec. 6. 1995. and all of which are incorporated herein by reference. 

## BRIEF SUMMARY OF THE INVENTION 

1. Technical Field 

This invention relates to an improved metal› organophosphite ligand complex catalyzed hydrofonnyla› tion process directed to producing aldehydes. More particu› larly this invention relates to the use of water to prevent and/or lessen hydrolytic degradation of the organophosphite ligand and deactivation of the metal-organophosphite ligand complex catalyst of such hydroformylation processes. 

2. Background of the Invention 

tible to hydrolysis in one degree or another, the rate of hydrolysis of organophosphites in general being dependent on the stereochemical nature of the organophosphite. In general, the bulkier the steric environment around the phos- phorus atom. the slower the hydrolysis rate. For example. tertiary triorganophosphites such as triphenylphosphite are more susceptible to hydrolysis than diorganophosphites, such as disclosed in U.S. Pat. No. 4,737.588, and organopo› lyphosphites such as disclosed in U.S. Pat. Nos. 4,748.261 and 4.769.498. Moreover, all such hydrolysis reactions invariably produce phosphorus acidic compounds which catalyze the hydrolysis reactions. For example. the hydroly› sis of a tertiary organophosphite produces a phosphonic acid diester, which is hydrolyzable to a phosphonic acid monoester. which in turn is hydrolyzable to H$_{3}$PO$_{3 }$ acid. Moreover, hydrolysis of the ancillary products of side reactions, such as between a phosphonic acid diester and the aldehyde or between certain organophosphite ligands and an aldehyde, can lead to production of undesirable strong aldehyde acids. e.g .• n-C$_{3}$H$_{7}$ CH(OH)P(OXOHh 

Indeed even highly desirable sterically-hindered organo› bisphosphites which are not very hydrolyzable can react with the aldehyde product to form poisoning organophosphites. e.g .. organomonophosphites. which are not only catalytic inhibitors, but far more susceptible to hydrolysis and the formation of such aldehyde acid byproducts. e.g., hydroxy alkyl phosphonic acids. as shown. for example. in U.S. Pat. Nos. 5,288,918 and 5364.950. Further, the hydrolysis of organophosphite ligands may be considered as being autocatalytic in view of the production of such phosphorus acidic compounds. e.g .. H$_{3}$ P0$_{3}$ • alde› hyde acids such as hydroxy alkyl phosphonic acids, H$_{3}$P0$_{4 }$ and the like, and if left unchecked the catalyst system of the continuous liquid recycle hydrofonnylation process will become more and more acidic in time. Thus in time the eventual build-up of an unacceptable amount of such phos› phorus acidic materials can cause the total destruction of the organophosphite present. thereby rendering the hydroformy› lation catalyst totally ineffective ( deactivated) and the valu- able rhodium metal susceptible to loss, e.g., due to precipi› tation and/or depositing on the walls of the reactor. Accordingly. a successful method for preventing and/or lessening such hydrolytic degradation of the organophos› phite ligand and deactivation of the catalyst would be highly desirable to the art. 

It has now been discovered that water may be employed to effectively remove such phosphorus acidic compounds and thus prevent and/or lessen hydrolytic degradation of organophosphite ligands and deactivation of metal› organophosphite ligand complex catalysts that may occur over the course of time during a hydrofonnylation process directed to producing aldehydes. Although both water and acid are factors in the hydrolysis of organophosphite ligands, it has been swprisingly discovered that hydroformylation reaction systems are more tolerant of higher levels of water than higher levels of acid. Thus, the water can be used to remove acid and decrease the rate of loss of organophosphite ligand by hydrolysis. It has also been surprisingly discov› ered that minimum loss of organophosphite ligand occurs when a hydroformylation reaction product fluid containing a metal-organophosphite ligand complex catalyst is contacted with water even at elevated temperatures. 

This invention relates in part to a process for separating one or more phosphorus acidic compounds from a hydro› fonnylation reaction product fluid containing said one or 

## DISCLOSURE OF THE INVENTION 

