Synthesis radiation-assisted processes

Another method of graft copolymer synthesis is a combination of microwave-based and conventional synthesis, i.e. using both microwave radiation as well as a chemical free radical initiator (e.g. ceric ammonium nitrate) together. This process is referred to as microwave assisted synthesis [47]. Although it yields a higher percentage grafting than the microwave initiated synthesis, the rehability of the synthesis process is low. 

The recent literature on microwave-assisted chemistry has reported a multitude of different effects in chemical reactions and processes and attributed them to microwave radiation. Some of these published results cannot be reproduced, however, because the household microwave ovens employed often have serious technical shortcomings. Published experimental procedures are often insufficient and do not enable reproduction of the results obtained. Important factors required for qualification and validation, for example exact records, reproducibility, and transparency of reactions/processes, are commonly not reported, which poses a serious drawback in the industrial development of microwave-assisted reactions and processes for synthesis of fine chemicals, intermediates, and pharmaceuticals. Technical microwave devices for synthetic chemistry have been on the market for a while (cf a.m. explanations) and should enable comparative investigations to be conducted under set conditions. These investigations would enable better assessment of the observed effects. It is, furthermore, possible to obtain a better insight into the often discussed (nonthermal) microwave effects from these experiments (Ref. [138] and Chapter 4 of this book). Technical microwave systems are an important first step toward the use of microwave energy for technical synthesis. The actual scale-up of chemical reactions in the microwave is, however, still to be undertaken. Comparisons between microwave systems with different technical specifications should provide a measure for qualification of the systems employed, which in turn is important for validation of reactions and processes performed in such commercial systems. 

The introduction of electrical, photo and radiation energies into ammonia synthesis process to assist activating dinitrogen or to change reaction pathway also attracts researching interest. If they can be introduced into the nitrogen fixation process, it can not only create some non-spontaneous reaction in thermodjmam-ics on the basis of electrical energy so as to extend the research field of ammonia synthesis quomodo, but can also reduce and break the limitation of conversion of ammonia synthesis caused by thermodjmamic equilibrium. 

The microwave-assisted (MW) synthesis also promised to provide a green solution to the problem of synthesis of MOFs [36]. Indeed, the use of MW radiation decreases dramatically the time required to complete the synthesis of a number of MOFs, produces particles with the distribution shifted toward the nanosize range and reduces the energy consumption, thereby improving the economics of the process. It is important that MW helps to accelerate the stage... 

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