Scale-up of solvent-free methods

The former French company Prolabo developed two microwave systems for synthesis7. The machines were employed in several research laboratories mainly for solvent-free organic chemistry. They had monomodal rectangular waveguide sections that also served as microwave cavities. Cylindrical tubes could be inserted and rotated to increase thermal homogeneity and if required condensers could be fitted. Temperature measurement was by infrared pyrometry. Computer control enabled reaction monitoring with respect to temperature or power. 

Loupy et al.7 demonstrated that the smaller of the two microwave systems could process sample sizes of30-40 g or 70 ml. For scale-up of microwave assisted dry media organic chemistry, a larger reactor was developed. Examples of reactions conducted on this instrument, some of which are presented in Table 9.1, included esterification75, 

Scale-up factor a, b (mmol) Final temperature (°C) Yield (%) 

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