Two unrelated questions about FFA's

1. After reacting the FFA's with sulphiric acid the titration will show a number, say 1.0. That is with a certain amount of methanol, say 10%, in the mix right? Does this mean that the titration number is low by the % of methanol mixed in with the wvo? With 10% methanol the 1 ml used for the titration would be .9 ml wvo and .1 ml methanol.

Does that mean that the titration number after acid esterification needs to be multiplied by 1/the % of wvo, so 1/.9 or 1.11

2. What does the fatty acid look like and what happens to it during esterification? Does the molecular weight increase or decrease? What's the maxixmum theoretical yield?

1. Yes, correct.

2. FFA is miscible/soluble with the oil. It is most likely dark in colour (as can be witnessed by methanol extraction a la graemethechemist's technique). When esterified with methanol, its molecular weight increases because you are attaching the methyl group to the fatty acid - making a bigger molecule (Fatty Acid Methyl Ester, aka biodiesel).

What do you mean by "theoretical yield"? Say you have 100% FFA (free fatty acid) material, if you esterify with methanol then you will have >100% theoretical yield (nearly 110% yield based on FFA amount). If you get my gist.