39  5,744,649  40  The  hydroformylation  processes  of  this  invention  may  be  carried  out  using,  for  example,  a  fixed  bed  reactor,  a  fluid  bed  reactor,  a  continuous  stirred  tank  reactor  (CSTR),  or  a  slurry  reactor.  The  optimum  size  and  shape  of  the  catalysts  will  depend  on  the  type  of  reactor  used.  In  general,  for  fluid  bed  reactors.  a  small,  spherical  catalyst  particle  is  preferred  for  easy  fluidization.  With  fixed  bed  reactors.  larger  catalyst  particles  are  preferred  so  the  back  pressure  within  the  reactor  is  kept  reasonably  low.  The  at  least  one  reaction  zone  employed  in  this  invention  may  be  a  single  vessel  or  may  By  way  of  further  explanation  it  is  believed  the  free  heterocyclic  nitrogen  compound  serves  as  a  replacement  ligand  for  the  lost  carbon  monoxide  ligand  thereby  forming  a  neutral  intermediate  metal  species  comprising  a  complex  of  the  metal,  organopolyphosphite.  the  heterocyclic  nitrogen  compound  and  hydrogen  during  such  harsh  conditions.  e.g  .•  vaporization  separation.  thereby  preventing  or  minimizing  the  formation  of  any  such  above  mentioned  catalytic  inac› tive  or  less  active  metal  species.  It  is  further  theorized  that  the  maintenance  of  catalytic  activity.  or  the  minimization  of  its  deactivation.  throughout  the  course  of  such  continuous  liquid  recycle  hydroformylation  is  due  to  regeneration  of  the  active  catalyst  from  said  neutral  intermediate  metal  species  in  the  reactor  (i.e.  hydroformylation  reaction  zone)  of  the  particular  hydroformylation  process  involved.  It  is  believed  that  under  the  higher  syn  gas  pressure  hydroformylation  conditions  in  the  reactor,  the  active  catalyst  complex  com- prising  metal.  e.g  ..  rhodium.  organopolyphosphite,  carbon  monoxide  and  hydrogen  is  regenerated  as  a  result  of  some  of  the  carbon  monoxide  in  the  reactant  syn  gas  replacing  the  heterocyclic  nitrogen  ligand  of  the  recycled  neutral  inter› mediate  rhodium  species.  That  is  to  say.  carbon  monoxide  having  a  stronger  ligand  affinity  for  rhodium,  replaces  the  more  weakly  bonded  heterocyclic  nitrogen  ligand  of  the  An  alternate  method  of  transferring  acidity  from  the  hydroformylation  reaction  product  fluid  to  an  aqueous  frac› tion  is  through  the  intermediate  use  of  a  heterocyclic  amine  which  has  a  fluorocarbon  or  silicone  side  chain  of  sufficient  size  that  it  is  immiscible  in  both  the  hydroformylation  reaction  product  fluid  and  in  the  aqueous  fraction.  The  heterocyclic  amine  may  first  be  contacted  with  the  hydro› formylation  reaction  product  fluid  where  the  acidity  present  in  the  reaction  product  fluid  will  be  transferred  to  the  nitrogen  of  the  heterocyclic  amine.  This  heterocyclic  amine  layer  may  then  be  decanted  or  otherwise  separated  from  the  reaction  product  fluid  before  contacting  it  with  the  aqueous  fraction  where  it  again  would  exist  as  a  separate  phase.  The  heterocyclic  amine  layer  may  then  be  returned  to  contact  the  hydroformylation  reaction  product  fluid.  It  is  to  be  understood  that  while  it  may  be  preferred  to  employ  only  one  free  heterocyclic  nitrogen  compound  at  a  time  in  any  given  hydroformylation  process.  if  desired,  mixtures  of  two  or  more  different  free  heterocyclic  nitrogen  compounds  may  also  be  employed  in  any  given  process.  Moreover  the  amount  of  such  free  heterocyclic  nitrogen  compounds  present  during  harsh  conditions,  e.g.,  the  vapor› ization  procedure,  need  only  be  that  minimum  amount  necessary  to  furnish  the  basis  for  at  least  some  minimization  of  such  catalyst  deactivation  as  might  be  found  to  occur  as  a  result  of  carrying  out  an  identical  metal  catalyzed  liquid  recycle  hydroformylation  process  under  essentially  the  same  conditions,  in  the  absence  of  any  free  heterocyclic  nitrogen  compound  during  vaporization  separation  of  the  aldehyde  product.  Amounts  of  such  free  heterocyclic  nitrogen  com› pounds  ranging  from  about  0.01  up  to  about  10  weight  percent.  or  higher  if  desired,  based  on  the  total  weight  of  the  hydroformylation  reaction  product  fluid  to  be  distilled  should  be  sufficient  for  most  purposes.  Another  problem  that  has  been  observed  when  organopo› lyphosphite  ligand  promoted  metal  catalysts  are  employed  in  hydroformylation  processes.  e.g  .•  continuous  liquid  catalyst  recycle  hydroformylation  processes.  that  involve  harsh  con- ditions  such  as  recovery  of  the  aldehyde  via  a  vaporizer› separator,  i.e.,  the  slow  loss  in  catalytic  activity  of  the  catalysts  is  believed  due  at  least  in  part  to  the  harsh  condi› tions  such  as  exist  in  a  vaporizer  employed  in  the  separation  and  recovery  of  the  aldehyde  product  from  its  reaction  product  fluid.  For  instance,  it  has  been  found  that  when  an  organopolyphosphite  promoted  rhodium  catalyst  is  placed  under  harsh  conditions  such  as  high  temperature  and  low  carbon  monoxide  partial  pressure,  that  the  catalyst  deacti› vates  at  an  accelerated  pace  with  time.  due  most  likely  to  the  formation  of  an  inactive  or  less  active  rhodium  species,  which  may  also  be  susceptible  to  precipitation  under  pro› longed  exposure  to  such  harsh  conditions.  Such  evidence  is  also  consistent  with  the  view  that  the  active  catalyst  which  under  hydroformylation  conditions  is  believed  to  comprise  a  complex  of  rhodium.  organopolyphosphite,  carbon  monox› ide  and  hydrogen.  loses  at  least  some  of  its  coordinated  carbon  monoxide  ligand  during  exposure  to  such  harsh  conditions  as  encountered  in  vaporization,  which  provides  a  route  for  the  formation  of  catalytically  inactive  or  less  active  rhodium  species.  The  means  for  preventing  or  minimizing  such  catalyst  deactivation  and/or  precipitation  involves  car› rying  out  the  invention  described  and  taught  in  copending  U.S.  patent  application  Ser.  No.  08/756,789,  referred  to  above,  which  comprises  carrying  out  the  hydroformylation  process  under  conditions  of  low  carbon  monoxide  partial  pressure  in  the  presence  of  a  free  heterocyclic  nitrogen  compound  as  disclosed  therein.  Thus  the  possibility  of  metal  catalyst  deactivation  due  to  such  harsh  conditions  is  said  to  be  minimized  or  prevented  by  carrying  out  such  distillation  of  the  desired  aldehyde  product  from  $_{the }$metal-organopolyphosphite  catalyst  con› taining  reaction  product  fluids  in  the  added  presence  of  a  free  heterocyclic  nitrogen  compound  having  a  five  or  six  mem› bered  heterocyclic  ring  consisting  of  2 to  5  carbon  atoms  and  from  2  to  3  nitrogen  atoms,  at  least  one  of  said  nitrogen  atoms  containing  a  double  bond.  Such  free  heterocyclic  nitrogen  compounds  may  be  selected  from  the  class  con› sisting  of  diazole,  triazole,  diazine,  and  triazine  compounds,  such  as,  e.g  .•  benzimidazole  or  benzotriazole.  and  the  like.  The  term  "free"  as  it  applies  to  said  heterocyclic  nitrogen  compounds  is  employed  therein  to  exclude  any  acid  salts  of  such  heterocyclic  nitrogen  compounds,  ie  ..  salt  compounds  formed  by  the  reaction  of  any  phosphorus  acidic  compound  present  in  the  hydroformylation  reaction  product  fluids  with  such  free  heterocyclic  nitrogen  compounds  as  discussed  herein  above.  recycled  neutral  intermediate  rhodium  species  that  was  formed  during  vaporization  separation  as  mentioned  above,  thereby  reforming  the  active  catalyst  in  the  hydroformyla› tion  reaction  zone.  Accordingly  the  water  extraction  of  this  invention  will  not  only  remove  free  phosphoric  acidic  compounds  from  the  metal-organophosphite  ligand  complex  catalyst  containing  reaction  product  fluids,  the  water  also  swprisingly  removes  the  phosphorus  acidic  material  of  the  conversion  product  salt  formed  by  the  use  of  the  organic  nitrogen  compound  scav› enger  when  employed.  i.e  .•  the  phosphorus  acid  of  said  conversion  product  salt  remains  behind  in  the  water,  while  the  treated  reaction  product  fluid,  along  with  the  reactivated  (free)  organic  nitrogen  compound  is  returned  to  the  hydro- formylation  reaction  zone. 