Methanol is a primary raw material reactant used in the production of biodiesel. Methanol content of biodiesel fuel is an important factor in determining the tendency of the fuel to exhibit flammable characteristics. Additionally, a key quality factor for the alcohol reactant material is water content; methanol is hygroscopic to some degree. Water affects the extent and rate of the esterification reaction. Producers will value methanol purity tests to assure that water content is negligible at the start of production. Additionally, excess alcohol used during the production reaction can be recovered to minimize operating costs and environmental impacts. Evaluating the purity of recovered methanol enables the determination of reuse suitability. Lastly, the evaluation of methanol in a glycerin byproduct enables producers to market this fuel by-product as a commodity rather than manage it as a waste. Methanol content in biodiesel is performed in accordance with EN 14110.
ASTM D6751 Requirement: maximum methanol content of 0.2% mass. If the Flash Point is greater than 130° C, methanol analysis is not required.