Method for synthesizing polyoxymethylene dimethyl ethers

Abstract

The present invention relates to the field of chemical engineering and technology, in particular relates to the sub-field of synthesis of high quality alternative liquid fuel for engines from non-petroleum based feedstock, more particularly relates to a method for adjusting, controlling and optimizing the synthetic process of polyoxymethylene dimethyl ethers by utilizing chemical thermodynamic principle. The process of the present invention is achieved by conditions wherein the initial temperature of reaction is controlled at 100-120° C., then the temperature is reduced to 50-70° C. by successive stepwise cooling or programmed cooling, the reaction pressure is controlled at 0.1-4.0 MPa, and the molar ratio of paraformaldehyde or trioxane, metered in formaldehyde units, to methylal in the feedstock is 1.5:1-8:1. In the process, higher overall yield of the target product can be achieved within the same reaction time, and selectivity of products with higher polymerization degree of methoxy groups can be increased.

Dependencies are inferred from the claim text.