Warren Buffett's Berkshire Hathaway has announced plans to buy OxyChem from Occidental Petroleum for $9.7 billion. That's the largest deal the company has announced in three years and possibly the last it will undergo with Warren Buffett as CEO. OxyChem is a petrochemical company that is the leading provider of PVC, used to make everything from pipes to medical supplies to electrical conduits. It also makes water treatment chemicals and other products. “We look forward to welcoming OxyChem as an operatin ...