Question

1.) Look up the by-product of this reaction – glycerol – and determine whether this is

a useful molecule: would it make sense to save and recycle this by-product?

Explain.

2.) As mentioned above, soap molecules and biodiesel molecules have remarkably

different properties. Describe the intermolecular forces that lead to these

differences. (i.e., what intermolecular forces describe the behavior of soap

molecules? What IMFs dictate the behavior of biodiesel molecules?) Be specific!

3.) You will be using corn oil for your synthesis. Corn oil consists mainly of three

fatty acids in approximately the following ratio: 10% palmitic acid, 30% linoleic

acid, and 60% oleic acid. Keeping in mind that oils consist of triglycerides (as

shown above), calculate an average molar mass for corn oil.

Molar Mass of Palmitic Acid = 256.43 g/mol

Molar Mass of Linoleic Acid = 280.45 g/mol

Molar Mass of Oleic Acid = 282.47 g/mol

Average Molar Mass of Corn Oil = (10*256.43 + 30*280.45 + 60*282.47)/100

= (2564.3 + 8413.5 + 16948.2)/100 = 279.26 g/mol

Molar Mass of Corn Oil = 279.26 g/mol

4.) Assuming a density of 0.93 g/mL for corn oil, calculate the mass of corn oil you

will be used in this experiment (hint, you are measuring out 10.0 mL).

Mass of Corn Oil = density * volume

= (0.93 g/ml) * 10.0 mL = 9.30 g

Mass of corn oil = 9.3 g

5.) Using the molar mass you calculated in #6 along with the mass of starting

material and the balanced equation (Triacylglycerol Triglyceride → 3 Fatty Acid methyl Ester + Glycerol), calculate the theoretical yield

of both products in moles and mass.

Answer 1

1.

In the given reaction the byproduct glycerol is produced during the preparation of soap and biodiesel molecules as part of the soaponification and transesterification chemical reaction. The glycerol can be reused as drug for the wound and burn treatments and sweetener in the food industry. Vegetable oil contains fatty acids react with glycerol to form triglycerides as the  biological process.

2.

Soap molecule and biodiesel molecules have hydrocarbon chains are attracted to each other by Van der Waals forces (dispersion forces, London forces, weak intermolecular forces).

Biodiesel are the methyl ester of the long chain fatty acids have higher molecular weight than the soap molecules. The bigger the molecule the greater the intermolecular forces generated by dispersion forces hence the greater the melting temperature.

3. and 4.

The quantity used for this reaction = 9.3 gram of triglycride

5.

The yields of the products for the given transesterification reaction have been calculated as below,