Fast Microwave‐Assisted Synthesis, Calcination and Functionalization of a Silica Mesoporous Nanomaterial: UVM‐7

Abstract

We report here, for the first time, the use of a solid state microwave source for the synthesis, calcination and functionalization of a UVM‐7 based hybrid mesoporous silica material. The synthesis of the UVM‐7 material is obtained in 2 min at low power (50 W) by the combination of a microwave irradiation and the atrane route. Moreover, it has been successfully calcined and functionalized in just 13 and 4 min respectively with microwave assisted procedures. A total synthesis comprising each individually optimized step, can be executed in only 4 h including work‐up, by contrast to a typical synthesis that comprises several days. Savings higher than one order or magnitude are obtained in time and energy. Our example is a proof of concept of the potential use of solid state microwave generators for the ultrafast on‐command preparation of hybrid nanomaterials due to their accurate control and accelerating properties.

Scaled-up microwave-assisted batch and flow synthesis and life cycle assessment of a silica mesoporous material: UVM-7

“…This could also be advantageous, since in our previous results a longer irradiation time led to an increase in the volume of inter-particle pores and therefore the expected diffusion capacity. 8 As expected, the formation of a white solid in the reactor due to condensation and the growth of silica is observed experimentally. The process occurs quickly in about 10 minutes and is accompanied by a decrease in reflected power.…”

“…The UVM-7 prepared following conventional procedures has larger inter-particle pores, but typically this parameter is one of those that presents greater variation. 8 This fact opens the possibility of modulating larger pores in a finer way through a modification of the MW preparative conditions.…”

“…This could also be advantageous, since in our previous results a longer irradiation time led to an increase in the volume of inter-particle pores and therefore the expected diffusion capacity. 8…”

“…Following our previous results, as an initial approximation, we proposed a scaled synthesis process in which the use of energy was proportional to the amount of water. 8 Considering that we sought to multiply by 100 the amount of material, a microwave power of 5 kW was implied. This value is much higher than the combined potency of 800 W of the four solid state sources.…”

“…In this sense, the authors of the present work reported a microwave-assisted UVM-7 synthesis method that allows the use of solid-state microwave generation technology to prepare, calcinate, and functionalize a mesoporous silica material in only 4 hours. 8 In part, the success of the result is due to the use of solid-state (SS) microwave generators that allow the generation of radiation with a controlled and stable power, even for small powers, and with a narrow range of frequencies. 9 Compared to other silica materials such as zeolites or fumed silica that are usually prepared in large quantities, mesoporous materials are generally prepared only in batches and at the gram level, limiting their practical application.…”