Biodiesel and FAME synthesis assisted by microwaves: homogeneous batch and flow processes

Fatty acids methyl esters (FAME) have been prepared under microwave irradiation, using homogeneous catalysis, either in batch or in a flow system. The quality of the biodiesel obtained has been confirmed by GC analysis of the isolated product. While the initial experiments have been performed in a small scale laboratory batch reactor, the best experiment has been straightforward converted into a stop-flow process, by the use of a microwave flow system. Compared with conventional heating methods, the process using microwaves irradiation proved to be a faster method for alcoholysis of triglycerides with methanol, leading to high yields of FAME

Synthesis of highly stabilized ylides from N-[2-(1,3-benzazolylmethyl)]pyridinium salts

A series of new stable ylides has been synthesized by the reaction of N-[2-(1,3-benzazolylmethyl)]-pyridinium salts with electrophiles such as carbon disulphide, isothiocyanate derivatives, phenylisocyanate and benzoyl chloride in a two-phase system. Preparation of pyridinium ketene dithioacetal derivatives and attempts to transform them into N-(diheteroarylmethyl)pyridinium ylides are also described.Comisión Interministerial de Ciencia y Tecnología-CICY

Synthesis and structural study on α-substituted-1-styrylpyridinium salts. Reinvestigation of krohnke condensation

Kröhnke condensation of several cycloimmonium salts with p-dimethylaminobenzaldhyde has been studied. X-Ray diffraction, IR and Raman spectra, 1H-and 13C-NMR and UV spectra of the products are discussed, being compared, when necessary, with the starting pyridinium salts. All compounds showed the Z configuration, corresponding to the more stable structure, except one, in which steric factors were predominant