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Tin(IV)-based compounds (mono-n-butyltin hydroxide oxide ( a ), di- n -butyl-oxo-stannane ( b ), di-n-butyl tin dilaurate ( c ) and tin oxide ( d )) were used as catalysts in the hydrolysis of triacylglycerides (TGs). The effects of the nature and amount of the catalysts, the nature of the TGs, the temperature and reaction time were evaluated. Compared with the usual industrial processes, these systems showed excellent activities at mild temperatures and pressures, and low amounts of catalyst (ca. 0.3% w /w oil ). Fatty acid (FA) conversions of ca. 97% were obtained at 180 °C, 4 h at oil:water:catalyst a molar ratio of 1:24:0.01 and, using soybean oil. [ABSTRACT FROM AUTHOR]

Sn(IV) complexes (dimethyltin dineodecanoate ( 1 ), dibutyltin dineodecanoate ( 2 ), dioctyltin dineodecanoate ( 3 ), dimethyltin diundec-10-enoate ( 4 ), dibutyltin diundec-10-enoate ( 5 ), tributyltin undec-10-enoate ( 6 ) and tributyltin undecanoate ( 7 )) were tested as catalysts for transesterification or esterification in the presence of methanol, in order to investigate the effect of the substituents coordinated to the metal center. All complexes were active at relative high reaction temperatures, and their reactivity can be associated with the steric effects induced by the substituents (alkyls and carboxylates) at the metal center. [ABSTRACT FROM AUTHOR]

Abstract: Three Sn(IV) complexes, named butyl stannoic acid (BTA), di-n-butyl-oxo-stannane (DBTO) and dibutyltin dilaurate (DBTDL), were initially tested as catalysts for esterification reaction of fatty acids in the presence of methanol as alcoholysis agent. Parameters like reaction time, temperature, and catalyst amount were systematically evaluated in this work. All complexes were active at relative high reaction temperatures, but BTA displayed the highest activity. Former studies have already demonstrated that these same complexes display good catalytic activity in methanolysis of triacylglycerides (TAGs). These results prompted us to test BTA catalyst also in simultaneous esterification/transesterification reactions from a mixture of free fatty acids (FFAs) and TAGs in the presence of methanol. BTA was able to convert the mixtures in to fatty acid methyl esters (FAMEs) with good yields, with simple isolation processes. The results obtained and discussed in this work can help the development of new catalytic systems to biodiesel production from oils with very high acid content. [Copyright &y& Elsevier]