SINGAPORE (Reuters) - Industrial gases group Linde said on Tuesday it will spend $1.4 billion (£1.1 billion) to boost its Singapore gasification facilities to support the planned expansion of Exxon Mobil Corp's nearby integrated refining complex.The investment will enable Linde's facility on Jurong Island to supply additional hydrogen and synthesis gas to Exxon's Singapore refinery, the company said in a statement.Exxon's expansion project, which is expected to come online in 2023, would..