{TAIL ~ The metal} made {HEAD ~ Raschig rings} used as an auxiliary packing material in the present invention has a bulk volume of preferably 0.3 3.5 times that of the shaped catalyst and a packed density of preferably 0.5 1.5 kg/l 
{ TAIL ~ The metal } made { HEAD ~ Raschig rings } used as an auxiliary packing material in the present invention has a bulk volume of preferably 0.3 3.5 times that of the shaped catalyst and a packed density of preferably 0.5 1.5 kg / l
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH