Continuous process for making melt-processable optical grade ring-opened polycyclic olefin (co)polymers in a single-stage multi-zoned reactor

A two-step process for hydrogenating a feedstream essentially free of an unreacted monomer(s) from a polymerization zone, said feedstream consisting essentially of (i) an unsaturated polymer formed by ring-opening metathesis polymerization (ROMP) of at least one multi-ringed monoolefinically unsaturated cycloolefin monomer, selected from the group consisting of bicyclo› 2.2.1.!hept-2-ene ("norbornene" "NB") and substituted embodiments thereof, (ii) a diluent amount of C.sub.6 -C.sub.8 -cycloalkane, (iii) a lower C.sub.3 -C.sub.7 .alpha.-olefin, and (iv) spent polymerization catalyst for forming said unsaturated polymer, said two-step process comprising,

• (a) continuously introducing said feedstream directly from a polymerization zone into a first hydrogenation zone at a pressure in the range from 1380 kPa (200 psig)-5000 kPa (700 psig), and a temperature at which less than 10% of said polymer is isomerized in the presence of said spent polymerization catalyst present in an amount in the range from 0.5 part to 6.5 parts by wt/100 parts of polymer, a filter aid, and an effective amount of a nickel-containing hydrogenation catalyst in an amount sufficient to produce a partially hydrogenated feedstream;
• and, in a second step,
• (b) introducing said partially hydrogenated feedstream into a second hydrogenation zone at a pressure in the range from 1380 kPa (200 psig)-5000 kPa (700 psig), and a temperature at which less than 10% of said polymer is isomerized, without removing said polymerization catalyst introduced into said first hydrogenation zone, and mixing said partially hydrogenated feedstream with additional nickel-containing hydrogenation catalyst in an amount sufficient to produce a slurry of an essentially fully hydrogenated feedstream;
• whereby more than 97% of double bonds in the unsaturated feedstream are converted to single bonds without deleteriously affecting the hydrogenation catalyst which is recovered for reuse.