Experimental Process, Step 1 - Purification and Titration

The crude canola oil feedstock was obtained from a local Chick-fil-A restaurant (Figure 1).  Solid material was initially present in the feedstock and was filtered out using a vacuum pump (Figure 2/Video 1).  The oil was poured into a Buchner funnel.  Filter paper covered the porous plate (plate in funnel with holes in it), and prevented large particles of solid from passing through.

A stopper around the base of the funnel fit into the Buchner flask to prevent air from disrupting the vacuum.  The Buchner flask had an extension that connected rubber tubing to the vacuum pump.  The vacuum pump sucked air from the flask at a pressure value of 23 mm Hg/75 kPa.  This process is further explained in Figure 3.

     Figure 1 - Unprocessed oil feedstock           Figure 2 - Setup of filtration method

        Video 1 - Filtration of oil feedstock                   Figure 3 - Detailed filtration diagram

 An alternate method involved spinning feedstock samples in a centrifuge at 4000 revolutions per minute (Figure 4/Video 2). However, this was not effective in separating out solid material since the oil was too viscous.

              Figure 4 - Centrifuge setup                         Video 2 - Centrifuge test trial

An 8.0 gram sample of filtrate was mixed with a 5 mL, 1:1 mL co-solvent of isopropyl alcohol and toluene.  The co-solvent was needed to help dissolve the nonpolar filtrate in the [0.1M] NaOH aqueous solution.  A few drops of phenophthalein indicator were added to the solution to determine the endpoint of the neutralization reaction.  

 

After 9.9 mL of [0.1M] NaOH were added to the mixture, a pink color persisted for more than 30 seconds.  This color change marked the end of the titration.  A video of this process can be seen below in Video 3.

        Video 3 - Titration of processed oil feedstock

Calculations were done to determine the amount of moles of NaOH added during the titration and was found to be 9.9x10^(-4) mol NaOH.  This number was determined by multiplying the concentration of NaOH ([0.1M]) by the volume of NaOH added (0.0099 L).  Since the hydroxide concentration in sodium hydroxide is equal to the concentration in potassium hydroxide, it was determined that 9.9x10^(-4) mol KOH will be needed during transesterification.

 The molecular mass of KOH was multiplied to this number to determine the amount of grams of KOH needed, which was found to be 0.6555 grams.  The total acid number was determined by taking a ratio of milligrams of KOH needed with grams of filtered oil used.  This ratio will be used to determine amount of base catalyst needed in the transesterification process.