Chinese state oil giant Sinopec, Asia’s biggest refiner by capacity, will not buy Iranian oil even after the U.S. waiver on purchases of crude from Iran loaded on tankers as of March 20, a senior Sinopec executive said on Monday. Sinopec, officially known as China Petroleum & Chemical Corporation, is weighing the potential risks of Iranian oil trade and “basically won't buy” Iranian crude, the company’s president Zhao Dong said, as carried by Reuters. The U.S. Treasury Department’s…