20140364651 | METHOD FOR SYNTHESIZING POLYOXYMETHYLENE DIMETHYL ETHERS - 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 engine fuel from non-petroleum based feedstock, more particularly relates to a method for regulating and optimizing the synthetic process of polyoxymethylene dimethyl ethers 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 in the same reaction time, and selectivity of products with higher degree of polymerization of methoxy groups can be increased. | 12-11-2014 |