Occidental Petroleum will sell its chemicals arm OxyChem to Warren Buffett's Berkshire Hathaway for $9.7 billion, the company said on Thursday, marking its biggest divestment yet to slash debt after years of costly acquisitions. Shares of the U.S. oil and gas producer, however, fell more than 6% in morning trading. Roth MKM analysts said in a note the sale of OxyChem could weigh on free cash flow growth in coming years, as the unit was expected to contribute significantly to expansion. Scotiabank analyst Pa ...