According to the financial services provider, the deal over the metals, oil and European Energy sides of the business is worth $1.6 billion.
The bank is now continuing its work with Sempra Energy, the other partner in the joint venture, to sell the remaining power, gas and other energy business lines contained within the unit.
RBS also announced the sale of its retail and commercial banking business in India to HSBC in a deal worth $95 million.
This second deal is expected to be completed during the first half of 2011, subject to regulatory approval.
Bruce Van Saun, group chief financial officer for RBS, said: "We have made excellent progress in recent months with our disposal of non-core assets resulting in over 20 businesses sold so far.
âI am delighted that our Retail & Commercial (R&C) banking colleagues and customers in India will now become part of HSBC, one of the largest and most successful banking groups globally."
The R&C arm employs more than 1,800 staff who will be transferred to HSCB following the completion of the deal.
By Jim Ottewill