The recipe calls for 3.5 grams of sodium hydroxide (lye) per liter of oil. However, I did not use one liter of oil in the demonstration. I used 1.4 liters of oil.
Problem 2: So how many grams of sodium hydroxide (NaOH) do I need to weigh out?

Gasoline doesn't really freeze, but water in gasoline will. These bottles of methanol is used to dissolve water that might be in the gasoline. The recipe calls for 200mL of methanol per liter of oil. Problem 3: Again, I am using 1.4 liters oil, so how many mL of methanol do I need?

The bottle with an "X" is isopropyl alcohol and not methanol. Isopropyl alcohol will not work for making biodiesel. All bottles are 12 fluid ounces.
Problem 4: Does a 12 fl. oz. bottle of methanol have enough mL of methanol to fulfil the recipe for 1.4 liters of oil that you figured in problem 3?

Here is both the ball and stick model of methanol and the space filled model. The ball and stick model makes it easier to see what atom is connected to what other atom. The space filled model shows the true size of the atoms. Methanol is also called methyl alcohol.

Problem 8a: What part of the molecule shown is the "methyl" group?
Problem 8b: What part of the molecule shown is the "alcohol" group?

Here is a similar fat molecule but shown with the structural formula for the left 3 carbons and a skeletal formula for the long hydrocarbon chains.
Problem 10: Fats and oils are called triglycerides. Why are they called that?

When biodiesel is created, there are some contaminants of methanol, sodium hydroxide, and glycerin in the biodiesel. Water is sometimes used to remove those contaminants. Once in awhile the water and biodiesel will form an emulsion and not separate. The emulsion can last for days. To break up the emulsion, table salt can be added to the mixture.

When the oil is getting converted to biodiesel by the methanol/lye mixture, some of the oil is getting converted to soap by the lye. The soap will tie the water and biodiesel layers together to make an emulsion. The salt will interfere with the soap (like hard water does) and break up the emulsion allowing the biodiesel and water to separate.

Problem 15: Other salts could be used. What are the formulas for the following salts?
Potassium chloride
Calcium sulfate
Magnesium sulfate
Barium chloride

Remember, potassium hydroxide can be used instead of sodium hydroxide; however, the recipe of 3.5 grams of sodium hydroxide per liter of oil can't be used because potassium hydroxide weighs more per mole than sodium hydroxide. The active component is NaOH is the OH (hydroxide). KOH can be used but we have to have the same number of OH ions.
Problem 16a: How many moles of OH are in 3.5 grams of NaOH? (hint: moles of OH is the same moles of NaOH since there's one OH per NaOH molecule.)

Problem 16b: How many moles of OH are in 3.5 grams of KOH?

The rule of like dissolves like is quite useful in the making and cleanup of biodiesel. One method of cleaning up the raw biodiesel is to use water. Here I am pouring water into the raw biodiesel. Earlier you saw biodiesel has long hydrocarbon chains similar to diesel. Those are non-polar so water is not attracted to those chains. That makes biodiesel not soluble in water. However, there are some residues in the biodiesel that we have to remove. They are NaOH, glycerin (CH₂OH-CHOH-CH₂OH), and methanol (CH₃OH). Water (H₂O or HOH) is attracted to all of these and they will all dissolve in water.
Problem 19: What do you see that is in common with all four of these compounds (water, lye, glycerin, and methanol)?

Problem 20: The density of biodiesel is about 0.86 g/mL. After mixing the water and biodiesel will separate. Which one will be at the bottom?

Here is the pH from the first wash of biodiesel. It's between pH 11 and pH 12. You are suppose to continue the washes until all of the NaOH is gone and the wash water is neutral.

Problem 22: What will be the pH then?

I usually make up a liter of 0.5% w/v solution of NaOH. Other people use 0.1% w/v solutions, but I get more accuracy with 0.5%w/v.

Problem 25: How many grams of NaOH do you need to make one liter of 0.5% w/v NaOH solution (remember 0.5% w/v is 0.5g/100mL)?

I will then measure out 5 mL of the used oil. The problem with oil is that it won't mix with the NaOH solution that we will be adding to the oil. So I dissolve the oil in about 30mL of pure isopropyl alcohol. The alcohol dissolves both oil and water. That way the OH- in the NaOH solution can get to the H+ in the fatty acids in the oil.

Let us say I fill the buret to the 20.0 mL mark with the 0.5% w/v NaOH solution. At the point the color changed, the level was then 16.6 mL. So it took 3.4 mL of my 0.5% w/v solution to neutralize the fatty acids in the 5 mL of oil. So now I need to neutralize the fatty acids in the batch of 20 gallons of used cooking oil that will get converted to biodiesel.

Problem 26: How many extra grams of NaOH powder is needed to neutralize the fatty acids in that 20 gallons of use cooking oil based on that titration (L2)? (See spreadsheet below for setup).

Problem 27: This is the extra NaOH needed to neutralize the fatty acid in the oil. This is extra grams of NaOH. You still need to have 3.5 grams NaOH per liter. So what is the total grams of NaOH needed for these 20 gallons?

Problem 28: Other biodiesel producers use a 0.1% w/v NaOH solution and only titrate 1.0 mL of oil. So what cells above would need to be changed?

Methanol is used as a fuel in Indy Car racing (at least until 2007, then switched to ethanol). The oxygen in methanol (CH₃OH) gives it some built-in access to oxygen, which helps it burn faster. In biodiesel production, methanol is turned to methoxide, which attaches to the fatty acid side of the fat or oil. Because methanol is quite flammable, biodiesel processing should avoid any open flames. Only electric or solar heating should be used.

Before the methanol/NaOH mixture (methoxide) is added to the cooking oil, the cooking oil must be heated up to 130°F. The electric heating element hangs on the side with the heating elements going down inside. Knowing the specific heat of oil, the amount of energy needed to heat it up can be calculated. The specific heat of vegetable oil is 1.917 joules per gram per °C. Here is a drum containing 100 gallons of oil. The density of the oil is 0.92g/mL. The heating element puts out 500 watts.
Problem 30: Assuming no loss of heat, how many minutes (cell T2) will it take for the 500 watt heater to heat up 100 gallons of oil that starts at 71°F and ends at 130°F? (See spreadsheet below for setup help if you want to use it)

Problem 35a: Are the bonds covalent or ionic in methanol?

Here is a segment of cellulose, which is made from chains of glucose. Both ball and stick model and charge distribution models are shown. Paper towels (cellulose fibers) are often used to trap water that might be in the used cooking oil before the process begins. Cellulose is also used to dry the biodiesel after it gets washed with water.
Problem 38: Why does cellulose have a higher attraction to water than biodiesel?

Problem 39: What atoms show up as blue in the upper model?

Problem 40: What atoms are responsible for the grayish regions in the charge distribution model?

Problem 41: This is methanol molecule again. What kind of hybridized bonds are carbon using? (Choices are sp, sp², sp³).

Problem 42: How many lone pairs does oxygen have?

This is the end of biodiesel that has the carbon with the 2 oxygen atoms. That carbon is using what kind of hybridized bonds to connect to the 3 atoms (2 O and 1 C) that it is bonded to.

Problem 43: What bond angle (shown in yellow) is formed between the O-C-C?

Problem 44: What two atoms share a pi bond in this image?

Problem 45: On the methyl group on the left, what bond angle (shown in blue) is formed between the H-C-O bonds?

After the reaction that creates biodiesel is finished, the glycerin is drained off, and then I recover the excess (unreacted) methanol. The boiling point of methanol is 65°C (148°F). So I heat up the biodiesel/methanol mixture to 65°C and the mixture boils. Methanol vapors go up to the bend and condense back to a liquid. Some liquid travels down the condenser (a tube within a tube) and then drips down in to the right side flask. Cold or cool water is run through the condenser to cool the vapors and liquid. See the below diagram for added clarity. There is still some glycerin in the mixture and we don't want that in the methanol. Since glycerin's boiling point is considerably higher than that of methanol, none will contaminate the methanol recovered.

Problem 46: Look up and report the boiling point of glycerin.

My demonstration uses about half a gallon of biodiesel; however, most producers make 20 to 500 gallons at a time. I had a biodiesel co-op ask me about recovering 32 gallons of methanol from their 400 gallon biodiesel reactor tank. They needed a way to cool the methanol vapor. They wanted to use a 55 gallon barrel of water to cool the vapor and wondered if that was enough. That requires knowing the heat (enthalpy) of condensation of methanol. That value is the same as the heat of vaporization. Heat of vaporization needs energy (+ sign) and the heat of condensation releases energy (- sign). I searched for the both of them on the Internet because both values are the same. Here are the various values I found:
3340 Btu/gal, 506 Btu/lb, 1100 kJ/kg , 35278 kJ/kmol.
I want the value in calories because that makes the calculations with the water easier (1 calorie raises 1 grams of water 1 degree Celsius).

Problem 58: Why did I invert the Heat of vaporization in columns C and D?
Problem 59: What goes in E2?
Problem 60: To eliminate moles in D2, we need to change moles of water into grams. What values go into G2 and H2?
Problem 61: What values go into G3 and H3?
Problem 62: What goes in K2?
Problem 63: What goes in K3?
Problem 64: How many gallons will get evaporated (N2)? (Hint: gallons is between 5 and 20)
There weren't that many gallons that would need to evaporate, so that's the design they went with. They were smart to let me do the chemistry calculations to see if their design would work on paper.  Learning these kind of calculations may be difficult but not as difficult as spending thousands of dollars and many days building an apparatus that isn't going to work.

Earlier this semester I was amused by a TV commercial for a new cholesterol reducing drug that was essentially biodiesel. It's called "Lovaza". They call it the ethyl esters of fish oils. Biodiesel is the methyl esters of oils. Methanol is usually used to make biodiesel, but ethanol can also be used. Ethanol is not used as much because it's harder to buy 100% ethanol because of the licenses required; however, ethyl esters of oils and fats are also biodiesel. This drug is biodiesel using ethanol and fish oil as the starting materials. The main fatty acid in fish oil is eicosapentenoic acid. An image of the ethyl ester of the eicosapentenoic acid fatty acid is on the left. Eicosapentaenoic acid is one of the healthy "omega-3" polyunsaturated fatty acids. The omega end is at the end of the long chain. Omega-3 is referring to the third carbon from the end. That's where there is a double-bond. That's call unsaturated because there are fewer hydrogen atoms on the carbons. If satured with hydrogen atoms, there's just a single bond.
Problem 65: "Eicosa" is Greek for twenty. Why is "eicosa" used in the naming of the fatty acid part of this molecule?

Problem 66: "Penta" means five. Why is "penta" used in the name?

Instead of animal fat or vegetable oil as the feedstock for biodiesel, oils from algae show a lot of promise. ASU has a department that specializes in algae research. Below is a link to that department's page on Algae-based biofuel production.
http://larb.asu.edu/research/biofuel/

Bonus 5: In the article, there is this sentence:
In addition, we have demonstrated that some of the algal isolates can thrive at high concentration of carbon dioxide (up to 20% CO2) and take up waste nutrients (mainly N and P) rapidly from various types of wastewater. 
What do they mean by "N and P"?

Bonus 6: There's one person selling a book on making algae biodiesel at home and produced a video to promote it. Even though I'm all for alternative fuels, I'm a little skeptical of his claims. But it's still interesting. What are some of the things it says the book will teach you. Below is the link to the video.

http://www.youtube.com/watch?v=7Nf3M68S3ec