Use this calculator to find the molecular weight of various fats and oils. The total percentage cannot exceed 100%
Enter the fatty acid profile (% weight) of your vegetable oil or animal fat or select a feedstock to start with
Triglyceride feedstock
The molecular weight of a particular fat or oil depends on its
fatty acid profile. Fatty acid profile is the relative proportion of different
fatty acids in an oil or fat. In
order to determine the fatty acid profile, the oil is usually converted into
alcohol esters of fatty acid and then their proportionate weight is measured
using gas chromatography. The relative proportions of the esters are then
converted back to corresponding amounts of fatty acids. The fatty acids of
animal and plant origin are all straight carbon chains differing mainly in chain
length and the number of double bonds (saturation). A saturated fatty acid chain
with ‘n’ number of carbons will have a chemical structure of CH3- (CH2)n-2-COOH.
Once the fatty acid profile of the oil is known, it is easy to calculate the
average molecular weight of the oil. The molecular weight of a single fatty acid
‘i’ can be calculated as:
MWi = 14.027C-2.016d+31.9988
where ‘C’ is the
number of carbons and ‘d’ is the
number of double bonds. The average molecular weight of fatty acid mixture can
be calculated by dividing the sum of all reported fatty acid weights by total
moles in the mixture. Numerically,
Average molecular weight of fatty acids =
∑fi /
∑(fi/MWi)
Where, fi are the weight fraction of a reported
fatty acid. The molecular weight of the triglyceride (oil molecule) containing
three fatty acids can be calculated as:
MW=3*Average molecular weight of fatty acids+38.049