Abstract: A process is described for preparing polyoxymethylene by contacting a formaldehyde source with a catalyst of the formula I [CpvMLw]m+Zm/nn???(I) where M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh or Ir, Cp is a cyclopentadienyl ligand C5H(5-u)R1u, where u is from 0 to 5 and R1 is alkyl, alkenyl, aryl, heteroaryl, aralkyl, COOR2, COR2, CN or NO2, and R2 is H, alkyl, aryl or aralkyl, v is 1 or 2, each L is independently a nitrile, CO or a ligand displaceable by CO, w is an integer from 0 to 4, Z is an anion, and m and n are each independently an integer from 1 to 3.

Abstract: A process is described for preparing polyoxymethylene by contacting a formaldehyde source with a catalyst of the formula I [CpvMLw]m+Zm/nn???(I) where M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh or Ir, Cp is a cyclopentadienyl ligand C5H(5?u)R1u, where u is from 0 to 5 and R1 is alkyl, alkenyl, aryl, heteroaryl, aralkyl, COOR2, COR2, CN or NO2, and R2 is H, alkyl, aryl or aralkyl, v is 1 or 2, each L is independently a nitrile, CO or a ligand displaceable by CO, w is an integer from 0 to 4, Z is an anion, and m and n are each independently an integer from 1 to 3.