An apparatus and method of producing methanol includes reacting a heated hydrocarbon-containing gas and an oxygen-containing gas in a reactor; and adding a relatively cold hydrocarbon-containing gas, to be mixed directly with a mixture of the heated hydrocarbon-containing gas and the oxygen-containing gas, after formaldehyde is formed to inhibit decomposition of formaldehyde in the reactor, to provide a product stream comprising methanol and formaldehyde; and transferring heat from the product stream to the hydrocarbon-containing gas to heat the hydrocarbon containing gas.