CHARACTERIZATION OF FATTY-ACID METHYL-ESTERS BY THERMAL-ANALYSIS

The thermal stability of selected straight-chain (C6-C-14) esters of f atty acids has been studied by TG-DTG and DTA analysis. In DTG, a peak is detected between 84-degrees and 125-degrees-C followed by a main e ffect in the range 105-degrees-215-degrees-C, whereas in DTA only an e xothermic peak appears in the range of 126.5-degrees to 187-degrees-C (onset temperatures). The temperatures of these effects have been rela ted with ignition points, molecular weights and boiling points. The ch aracteristics of melting and recrystallization of the above fatty acid methyl esters and those with carbon numbers between C-14 and C24 have been established by DSC along the melting range between -83-degrees a nd 50-degrees-C. Polymorphism appears in caproic, heptanoic, palmitic and stearic acid methyl esters.