South American football’s governing body CONMEBOL also hit Boca with $200,000 fine and ordered them to play their next four home continental fixtures and four away games behind closed doors.
River have been awarded a 3-0 victory and progress to the quarter-finals where they will face Cruzeiro of Brazil.
The match was suspended at half-time after a number of River players emerged from the makeshift tunnel, designed to protect players from opposing fans, with their eyes streaming and burn marks on their skin.
Four River players needed hospital treatment for their injuries, with television images showing a figure in Boca’s supporters section reaching into the players’ tunnel with an aerosol can.
The match was goalless at the time of the suspension, with River holding a 1-0 aggregate lead from the first leg.
Boca president Daniel Angelici told local media the club will appeal the sanction.
"We wll appeal," he told La Nacion. "With this decision we are hostages to violence."