Removed from the game with Mists of Pandaria. All Enchanting spells for creating runed rods higher than copper and all Blacksmithing spells for crafting rods were removed due to Blizzard changing the design so that only one runed rod is ever needed. Copper Rods can be purchased from an enchanting or trade supplies vendor.
The item was not removed from character inventories and will still function - it just cannot be upgraded like in previous expansions. You will not need to destroy the rod and create a Runed Copper Rod.