Microwave-assisted Organic Reaction Enhancement

If the product is needed on a small scale, up to 100 g, the reaction can be scaled out rather than scaled up. The excellent reproducibihty together with automation can easily produce up to 100 g overnight. Bose et al. have described an alternative for minor scale-up where the use of the microwave-assisted organic reaction enhancement (MORE) technique reduces the need for organic solvents and increases atom economy by improving product selectivity and chemical yield, thus, minimizing the need for larger scale-up. 

Banik, B.K., Barakat, K.J., Wagle, D.R., Manhas, M.S. and Bose, A.K., Microwave-induced organic reaction enhancement (MORE) chemistry, Part 13. Microwave-assisted rapid and simplified hydrogenation, /. Org. Chem., 1999, 64, 5746-5753. 

Microwave-assisted polycondensation reactions in ILs have also allowed the enhanced synthesis of polyamides and polyurethanes the comparison between microwave synthesis conditions in ILs with conventional heating methods and conventional organic solvents has also been addressed [92, 93]. Pretreatment methods combining microwave irradiation and ILs for cellulose dissolution and modification have been also proposed [94, 95]. Microwave irradiation can enhance the solubility of cellulose in ILs and decrease the degree of polymerization of regenerated cellulose after IL dissolution, which can be beneficial for improving cellulose hydrolysis [95]. 

Numerous studies have been carried out on microwave-assisted organic synthesis, and chentists have observed that the chentical reaction rates can be enhanced by... 

In microwave-assisted synthesis, a homogeneous mixture is preferred to obtain a uniform heating pattern. For this reason, silica gel is used for solvent-free (open-vessel) reactions or, in sealed containers, dipolar solvents of the DMSO type. Welton (1999), in a review, recommends ionic liquids as novel alternatives to the dipolar solvents. Ionic liquids are environmentally friendly and recyclable. They have excellent dielectric properties and absorb microwave irradiation in a very effective manner. They exhibit a very low vapor pressure that is not seriously enhanced during microwave heating. This makes the process not so dangerous as compared to conventional dipolar solvents. The polar participants of organic ion-radical reactions are perfectly soluble in polar ionic liquids. 

Microwave-assisted living cationic ring-opening showed an enhanced polymerization rate in comparison to the reaction in common organic solvents the ionic liquid was eSiciently recovered and reused in new reaction cycles, completely avoiding the use of volatile organic compounds [20]. 

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