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