Lab Investigation: Creating a micro-emulsion
In many industries chemicals are used to make processes more efficient and economic. This is
especially true within the oil industry. In a lot of our day to day activities we use a variety of oil products.
In order to make these products they need to extract oil from the ground,
transport it to upgraders and refineries for societies needs. The oil in the
ground is not pure it is mixed with many impurities this is called bitumen.
The bitumen is very difficult to transport as it is viscous. Many of the
methods to get to the oil have been to take the bitumen out of the ground
and then to separate it on the surface. Industries are in search of ways to
Photo from Fort McMurrary.
retrieve the oil part of the bitumen and leave the impurities in the ground.
Oil trapped in Sand.
These methods are called in situ or “in place” methods. One of the methods could be
revolutionary to oil recovery. This method involves placing a chemical compound in the oil reserve that
reacts with the bitumen and allows the oil to separate. A drilling rig is put in the oil reserve and the
separated oil is then pumped out.
The chemical compound that is used is a nanocatalyst which means a very small catalyst. A
catalyst is a compound that initiates or accelerates a chemical reaction. These nanocatalysts are difficult
to make but start with adding two micro-emulsions together. A micro-emulsion is a system of a polar
solution, non-polar solution and surfactant. A micro-emulsion is optically isotropic which means it looks
like a one solution; a homogeneous mixture. These are highly sensitive to temperature but they are
stable at room temperature.
There are two main types of micro-emulsions.
The first type of oil in water (O/W) where there are
tiny little drops of oil surrounded by surfactant and in
water. The second type is water in oil (W/O). In this
micro-emulsion there are tiny droplets of water
surrounded by surfactant in oil. The surfactant is very
important to allow the oil and water to mix.
In order to create an emulsion you need the proper ratio of surfactant, non-polar solution and
polar solution. In this laboratory exercise you will alter the ratio of surfactant (AOT), heptane and water
in order to create a micro-emulsion. To create the micro-emulsion a surfactant must be dissolved in
heptane and then some water is added. For the lab the total volume of the solution will be 10 mL. The
solution will be 90% heptane and 10% water so that means 1mL water and 9 mL heptane.
To create a micro-emulsion you need to have a proper amount of water to surfactant mole
ratio. If the incorrect ratio is used then two things could occur. The first is a milky or cloudy solution or
the second will be a complete separated phases.
Problem
What ratio of water to surfactant, 10 or 40, will produce a micro-emulsion where the solution is 10%
water and 90% heptane, in 10mL total volume?
Pre Lab Questions:
1. Determine the mass of dioctyl sulfosuccinate sodium salt that is needed to create a water to
surfactant mole ratio of 10.
2. Determine the mass of dioctyl sulfosuccinate sodium salt that is needed to create a water to
surfactant mole ratio of 40.
Materials:
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3.1 g of AOT (dioctyl sulfosuccinate sodium salt MW: 444.55 g/mol)
27 mL of heptane
3 mL of distilled
10 mL graduated cylinder
3-20 mL glass vials with caps
10 mL Graduated pipette (or 10 mL graduated cylinder)
Procedure:
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Label 3 glass vials V1, V2, and V3.
Weigh 2.47 g of AOT in V1.
Weigh 0.62 g of AOT in V2.
Put 0g of AOT in V3.
Measure 9 mL of heptane and put 9 mL in each glass vial.
Shake glass vial until all of the AOT has been dissolved in the heptane.
Using a graduated cylinder measure 1 mL of water and put in 1 mL in each glass vial.
Shake the glass vial.
Record your observations.
Evidence
Ratio of
Components
Mass of Surfactant
(AOT)
(g)
Volume of
Heptane
(mL)
Volume of Water
(mL)
V1
V2
V3
Questions for Synthesis:
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4.
Describe and explain which glass vial produced a micro-emulsion.
Describe and explain which glass vial produced a bi-layered mixture?
Explain which layer was the heptane and water in the 2 layer solution?
Design a simple experiment to prove which layer was the water.
Evaluation:
Observation of
Solution