This is an experimental demonstration of a new homogeneous gas phase chemical reaction whose existence is predicted by kinetic modeling, a reaction in which methanol selectively reduces sulfur trioxide to sulfur dioxide. If, as predicted, this reaction occurs under conditions that would make its use practical in boilers and furnaces, it could be the basis of a new process that would significantly improve the efficiency of heat recovery. In present practice, boilers and furnaces are operated with an intentional loss of efficiency in order to avoid corrosion problems due to sulfur trioxide. A process for selective sulfur trioxide reduction would also eliminate the ammonium disulfate fouling problems which presently hamper postcombustion reduction with ammonia. Commercialization of a process for selectively reducing sulfur trioxide to sulfur dioxide will allow improved boiler and furnace efficiencies and facilitate the use of post combustion nitrogen oxides control technologies. The former would reduce America's dependence on imported oil while the latter would help solve the acid rain problem.