Dear friend Abdelhalim Balouli

You can calculate the yield of biodiesel based on the weight. The biodiesel yield percentage can be calculated using the following formula:

biodiesel yield % = (biodiesel weight / initial oil sample weight) * 100

Where biodiesel weight is the mass of the biodiesel obtained after transesterification and initial oil sample weight is the mass of the oil used for transesterification².

However, since the upper layer contains unreacted oil and intermediate products, you can use a more accurate method to determine the yield of biodiesel. You can use gas chromatography (GC) or high-performance liquid chromatography (HPLC) to determine the amount of unreacted oil and intermediate products in the upper layer. The amount of unreacted oil and intermediate products can then be subtracted from the mass of the upper layer to obtain the mass of pure biodiesel. The yield of biodiesel can then be calculated using the formula mentioned above¹.

Here are some references that might help you:

- ¹ [Determination of Biodiesel Yield by Gas Chromatography](https://www.sciencedirect.com/science/article/pii/S1876610217320649)

- ² [How can I calculate the yield of biodiesel?](https://www.researchgate.net/post/How_can_I_calculate_the_yield_of_biodiesel)

- ³ [Optimized Biodiesel Production from Waste Cooking Oil (WCO ... - Nature](https://www.nature.com/articles/s41598-019-55403-4) This is my favorite article.

- 4 How to determine biodiesel yield? | ResearchGate. https://www.researchgate.net/post/How_to_determine_biodiesel_yield.

- 5 Study on Yield percentage of Biodiesel from Waste cooking oil using .... http://ripublication.com/ijaer21/ijaerv16n2_11.pdf.

Some of my publications can be of interest to you

1. Chapter Future Direction of Biodiesel in the Next Decade

2. Poster Reaction Energy: Fueling tomorrow

3. Chapter Pretreatment of Cellulosic Biomass for Better Yield of Bioet...

4. Conference Paper A Review of Biodiesel Policy around the Globe

5. Article Epidemiology, 17 (6), S146-S147, November 2006, Children's E...

I hope this helps.

Biodiesel Yield (%) = (Weight of Biodiesel Obtained / Weight of Initial Feedstock) x 100