Study On Condensation Reaction Of Aromatic Aldehydes Under Microwave High-speed Airflow

Based on the traditional solid-state reaction which exists a number of deficiencies, this paper presents a new type of solid-state reaction method ---microwave-assisted high-speed air-solid phase reaction, meanwhile designing, processing, setting up and commissioning this apparatus.using of the device and method successfully achieved with aromatic aldehydes and active methylene compounds in the condensation reaction and synthesized the target produce whose structure used FT-IR, MS,'HNMR determined. At the same time according to the experment, we obtained the optimum conditions of benzaldehyde reactions:the primary pressure 0.4MPa, microwave power of 1000 w, under the conditions of the molar ratio of 1:1 condensation. The best reaction time and yield corresponding to Nitrobenzaldehyde, o-nitrobenzaldehyde, p-hydroxybenzaldehyde, respectively isopropylidene malonate, m-nitrobenzaldehyde, on chlorobenzaldehyde and barbituric acid were 3min/92.2%,3min/86.2%,2min/95.6%,3min/93.2%,2min/95.2%.In contrast the best reaction time and yield of high-speed air-solid phase reaction without microwave-assisted were 5min/86.9%,6min/83.3%,5min/93.2%, 5min/90.2%,5min/97.2%.So the advantage of microwave-assisted high-speed airflow visible solid-state reaction is shorter reaction time and higher yield, and its mechanism was discussed.Studies have shown that materials cycle, microwave leakage, the reaction yield, pollution-free and so on. Reach the designed requirements, the method of microwave-assisted high-speed airflow principle of solid-state reaction is feasible and suitable for many organic compounds in the preparation. Compared with traditional methods:short reaction time, high reaction yield, easy operation, simple process, low cost, and the reaction does not require solvents, green environmental protection, easy-to-industrialization.It can achieve the target product of the industrial production.