Temperature influence on molecular weight determination

Marcel Dekker, Inc. 270 Madison Avenue, New York, New York 10016 

It is obvious that the solubility of asphaltenes in a given solvent increases as the temperature of measurement is increased. For example, the molecular weight of the asphaltenes from Bitumen 200 Elf is 1440 mol/g defined at 60°C and 10050 mol/g defined at 37 °C. It is clear that at 37°C, asphaltenes were not completely solved in the toluene and the defined molecular weight is probably the molecular weight of the micelles which are formed from 6 to 8 asphaltene molecules. The molecular weight of 1440 is very close to the molecular weight of asphaltenes reported in many references [1,9]. 

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