Analyses and rates of reactions influenced by water in synthesis of polyoxymethylene dimethyl ethers from trioxane and methylal

•The reaction networks for synthesis of PODEn were studied.•The adsorption of water on the catalyst reduces the reaction rate.•The power law and LHHW kinetics model were built and validated. Polyoxymethylene dimethyl ethers (PODEn) are promising diesel blend components with high oxygen content, high cetane number and similar properties to diesel. In this paper, we conducted a series of experiments for synthesizing PODEn over a HZSM-5 catalyst in a batch stirred autoclave using methylal and trioxane as reactants. Our research focused on the water influence on these syntheses by contrasting the differences from experiments with or without water and built reaction pathway and rate laws. The experimental and kinetic results showed that decrease of water amount could not only increase yields of the PODEn but also reduce the influences on formation rates of the desired products and eliminate some side reactions. Therefore, it is necessary to optimize water amount in the raw materials for balancing costs of the feed and operation as well as yields of the products to maximize the economy in a commercial production of PODEn.