Application of molybdenum trioxide catalyst for inhibiting side reaction in process of preparing dimethyl carbonate from CO2 and methanol and recycling dehydrating agent

The invention provides application of a molybdenum trioxide catalyst for inhibiting side reaction in a process for preparing dimethyl carbonate (DMC) from CO2 and methanol and recycling a dehydrating agent. In the process, DMC is synthesized by taking methanol and CO2 as reactants, 2-cyanopyridine (2-CP) as a dehydrating agent and molybdenum trioxide as a catalyst. And collecting the reacted 2-CP dehydration product 2-picolinamide (2-PA) and a molybdenum trioxide catalyst, treating, and regenerating into 2-CP under a high-temperature condition. By utilizing the process route, cyclic regeneration of 2-CP can be realized, and the reaction cost caused by introduction of a dehydrating agent is greatly reduced. According to the process route for regenerating 2-CP from 2-PA, the 2-CP product can be obtained with high yield, and under the conditions of 250 DEG C and 3 hours, the conversion rate can reach 86.2%, and the selectivity can reach 93.0%. The molybdenum trioxide catalyst can obviously inhibit the reaction p