BIODIESEL TITRATION LAB

This assay measures the level of free fatty acids present in oil and therefore determines the amount of additional sodium hydroxide that needs to be added during the reaction to neutralize the oil.

NOTE: Students may be asked to complete more than one trial, then average the results.

Materials

• 
  Samples of fresh and used canola oil (If used frying oil is not available, create used oil by heating it until it turns brown. Consider obtaining some from the cafeteria, if canola oil is used for cooking.)


• 
  99% isopropanol solution (IPA)
  


• • Titrant – 0.1% solution of sodium hydroxide ( 1 g NaOH added to 1 L of water or 0.025 moles/litre of titrant)


• 
  • pH indicator (phenolphthalein, turmeric or other indicator able to indicate pH 7.0)


• 
  • Clean sample cup (100 mL Erlenmeyer flask or plastic sample cup)


• 
  • Disposable plastic pipettes or graduated cylinders capable of an exact measurement of 1 mL of oil


• 
  • Burette

Test Method

1. Measure 10 mL of 99% isopropanol solution into an Erlenmeyer flask.
2. Add a small amount of pH indicator to the solution (3 drops of phenolphthalein or a dusting of
turmeric powder).
3. Use a disposable plastic pipette or graduated cylinder to measure exactly 1 mL of oil and pour it into the flask.
4. Stopper the flask and mix the solution of alcohol and oil by shaking it gently.
5. Fill a burette with the titrant (0.1% NaOH).
6. Slowly add the titrant to the Erlenmeyer flask and mix during addition.
7. Stop adding the titrant once pH =7 is determined by the colour change. For example if using
tumeric, the colour changes from yellow to pink. If the solution remains pink for at least 10
seconds the pH is 7; if the colour turns bright red, too much titrant was added and it is necessary to start over.
8. Record the amount in mL of titrant added to create a colour change.
9. This value (acid number) indicates the amount of additional NaOH required to neutralize the free fatty acids in g/L.
10. Calculate the amount of NaOH required to conduct the reaction using the following equation –
NaOH required (g/L of oil) = 3.5 + acid number.
Example if 2 mL of solution is required, acid number = 2

A Simple BioDiesel Experiment

Biodiesel is a diesel fuel that is made by reacting vegetable oil (cooking oil) with other common chemicals. Biodiesel may be used in any diesel automotive engine in its pure form or blended with petroleum-based diesel. No modifications are required, and the result is a less-expensive, renewable, clean-burning fuel. Here's how to make biodiesel from fresh oil. You can also make biodiesel from waste cooking oil, but that is a little more involved, so let's start with the basics.
Materials for Making Biodiesel

• 
  1 liter of new vegetable oil (e.g, canola oil, corn oil, soybean oil)
  3.5 grams (0.12 oz.) sodium hydroxide (also known as lye). Sodium hydroxide is used for some drain cleaners, such as Red Devil™ drain cleaner. The label should state that the product contains sodium hydroxide (not calcium hypochlorite, which is found in many other drain cleaners)


• 
  200 milliliters (6.8 fl. oz.) of methanol (methyl alcohol). Heet™ fuel treatment is methanol. Be sure the label says the product contains methanol (Isoheet™, for example, contains isopropyl alcohol and won't work).


• 
  blender with a low speed option. The pitcher for the blender is to be used only for making biodiesel. You want to use one made from glass, not plastic, since the methanol you will use can react with plastic.


• 
  digital scale [to accurately measure 3.5 grams (0.12 oz.)]
  glass container marked for 200 milliliters (6.8 fl. oz.). If you don't have a beaker, measure the volume using a measuring cup, pour it into a glass jar, then mark the fill-line on the outside of the jar.


• 
  glass or plastic container that is marked for 1 liter (1.1 quart)
  wide mouth glass or plastic container that will hold at least 1.5 liters (2-quart pitcher works well)
  safety glasses, gloves, and probably an apron. You do not want to get sodium hydroxide or methanol on your skin, nor do you want to breathe the vapors from either chemical. Both chemicals are toxic. Please read the warning labels on the containers for these products! Methanol is readily absorbed through your skin, so do not get it on your hands. Sodium hydroxide is caustic and will give you a chemical burn. Prepare your biodiesel in a well-ventilated area. If you spill either chemical on your skin, rinse it off immediately with water.

Let's Make Biodiesel!

• 
  You want to prepare the biodiesel in a room-temperature (70° F) or warmer room since the chemical reaction will not proceed to completion if the temperature is too low.
  If you haven't already, label all your containers as 'Toxic - Only Use for Making Biodiesel', since you don't want anyone drinking your supplies and you don't want to use the glassware for food again.


• 
  Pour 200 ml methanol (Heet) into the glass blender pitcher.
  Turn the blender on its lowest setting and slowly add 3.5 g sodium hydroxide (lye). This reaction produces sodium methoxide, which must be used right away or else it loses its effectiveness. (Like sodium hydroxide, it can be stored away from air/moisture, but that might not be practical for a home setup.)


• 
  Mix the methanol and sodium hydroxide until the sodium hydroxide has completely dissolved (about 2 minutes), then add 1 liter of vegetable oil to this mixture.

Continue blending this mixture (on low speed) for 20-30 minutes.

Pour the mixture into a wide-mouth jar. You will see the liquid start to separate out into layers. The bottom layer will be glycerin. The top layer is the biodiesel.

Allow at least a couple of hours for the mixture to fully separate. You want to keep the top layer as your biodiesel fuel. If you like, you can keep the glycerin for other projects. You can either carefully pour off the biodiesel or use a pump or baster to pull the biodiesel off of the glycerin.

Thinking Through Years Ahead

Biodiesel Production

Biodiesel is the most common biofuel in Europe. It is produced from oils or fats using transesterification and is a liquid similar in composition to mineral diesel. Its chemical name is fatty acid methyl (or ethyl) ester (FAME). Oils are mixed with sodium hydroxide and methanol (or ethanol) and the chemical reaction produces biodiesel (FAME) and glycerol. 1 part glycerol is produced for every 10 parts biodiesel.

Biodiesel is made by chemically altering an organic oil (typically vegetable oil) through a process called "transesterification". Essentially, the process thins down the oil to allow it to run in an unmodified diesel engine.

In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. These reactions are often catalyzed by the addition of an acid or base.


Transesterification: alcohol + ester → different alcohol + different ester


Production Process

Filtering and Heating

Oil is filtered to remove dirt, and other non-oil material. Water is removed because its presence causes the triglycerides to hydrolyze to give salts of the fatty acids instead of undergoing transesterification to give biodiesel.

This is often accomplished by heating the filtered oil to approximately 120 °C. At this point, dissolved or suspended water will boil off. A sample of the cleaned oil is titrated against a standard solution of base in order to determine the concentration of free fatty acids (RCOOH) present in the waste vegetable oil sample. The quantity of base required to neutralize the acid is then calculated.




Transesterification

While adding the base, a slight excess is factored in to provide the catalyst for the transesterification.
The calculated quantity of base (usually sodium hydroxide) is added slowly to the alcohol and it is stirred until it dissolves. Sufficient alcohol is added to make up three full equivalents of the triglyceride, and an excess is added to drive the reaction to completion.

The solution of sodium hydroxide in the alcohol is then added to a warm solution of the waste oil, and the mixture is heated (typically 50 °C) for several hours (4 to 8 typically) to allow the transesterification to proceed.

Used oil (straight vegetable oil) recycling requires titration. We do a titration to find out how much free fatty acid is present and to find out how much to compensate for it by adding more lye so there's some left for the desired biodiesel reaction.The biodiesel reaction needs alkaline lye (NaOH) or KOH, as a catalyst (methanol and vegetable oil wont' react to make biodiesel by themselves) Waste oil contains free fatty acids (FFA), and the free fatty acids will with lye to make soap before the lye has a chance to participate in making biodiesel.

Washing

There are a number of water-soluble impurities left in biodiesel after the reaction and initial settling is complete.. Biodiesel should be washed to remove the excess catalyst, alcohol and other impurities.When Biodiesel is first made it is quite caustic with a pH of between 8.0 and 9.0.

Washing with plain water is sufficient to wash out all remaining catalyst, bringing the pH down to near neutral territory. Since Biodiesel has a lower specific gravity than water, the water will sink to the bottom and the Biodiesel will remain over the water.

In the first wash, the water will turn almost totally white. This is because a form of soap is created when water comes in contact with the catalyst in the Biodiesel. It should clear up as the soap washes out with sub sequent washings.

http://www.biodieselcommunity.org/

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Thinking Through Years Ahead

Biofuels

Biofuels are any kind of fuel made from living things, or from the waste they produce. Biofuel can be produced from any carbon source that can be replenished rapidly e.g. plants. Many different plants and plant-derived materials are used for biofuel manufacture. The two most prevalent biofuels are ethanol, currently produced from sugar or starch crops, and biodiesel, produced from vegetable oils or animal fats Biodiesel was probably the first of the alternative fuels to really become known to the public. Ethanol for fuel is made through fermentation, the same process which produces it in wine and beer.

Plants absorb carbon dioxide as they grow which is released when biofuels are burnt. .Some additional energy is required to grow and process biofuels but the net carbon dioxide emitted is less than the alternative of burning fossil fuels. The great advantage of biodiesel is that it can be used in existing vehicles with little or no adaptation necessary.

With near record oil prices, the future of biofuel—made from plant material—is of keen interest worldwide. Global biofuel production has tripled from 4.8 billion gallons in 2000 to about 16.0 billion in 2007, but still accounts for less than 3 percent of the global transportation fuel supply.

Biofuels are essentially a way to convert solar energy into liquid form via photosynthesis. One of the greatest concerns raised about them, however, is their net energy balance—i.e., whether production of the fuels requires more energy inputs (particularly fossil energy, in the form of fertilizers, tractor fuel, processing energy, etc.) than is ultimately contained in the biofuels themselves. Advances in technology have improved production efficiency, giving all current biofuels a positive fossil energy balance.

Gas combustion engines running on Bioethanol, which is produced from agricultural crops, sugar cane or bio-mass, burn basically the same as gasoline. They both emit CO2 during combustion. But the burning of ethanol recycles the CO2 because it has already been removed from the atmosphere by photosynthesis during the natural growth process. In contrast, the use of gasoline or diesel injects quantities of CO2.

Jatropha

Jatropha Curcas ‘Linneus’ is recognized as a plant of many uses and is generally well-known. The plant grows to about 3 meters high and produces seed that contain an inedible vegetable oil that is used as a source of fuel. Known as tuba tuba or tubang bakod or physic nut, it has been planted in the Philippines for quite some time but it was used mainly as fencing since it animals do not eat the leaves. As Jatropha is toxic, it is not eaten by goats or other animals It is a vigorous, drought and pest resistant plant and has phytoprotective action against pests and pathogens and thus provides additional protection to intercropped plants. The trees are deciduous, shedding the leaves in the dry season. Flowering occurs during the wet season and two flowering peaks are often seen.

Many parts of Jatropha plants have been used historically by local cultures. Even the oil has applications as a medicine, a lubricant or as a fuel. The oil content is 35-40% in the seeds and 50-60% in the kernel. The oil contains 21% saturated fatty acids and 79% unsaturated fatty acids. The trees are easy to propagate from seed and cuttings and start bearing fruit within 9-12 months. The plant is a drought-resistant perennial, growing well in marginal/poor soil. It is easy to establish, grows relatively quickly and lives, producing seeds for so many years. This highly drought-resistant spe-cies is adapted to arid and semi-arid conditions. The current distribution shows that introduction has been most successful in the drier regions of the tropics with annual rainfall of 300-1000 mm.

Other known benefits:

it is capable of stabilizing sand dunes,
it does not exhaust the nutrients in the land
it is drought resistant