Explosive Medicine

You’ve probably heard of Alfred Nobel, the inventor of dynamite and gelignite. The commercialisation of these explosives enabled him to accumulate great wealth during his lifetime which, by the terms of his will signed in 1895, was used to establish the Nobel Prize. In later life he was prescribed Trinitrin, a medication used to relieve a heart condition known as angina.

What do dynamite, gelignite and Trinitrin all have in common?

They all contain nitroglycerin!

This is not a story about the life of Alfred Nobel.

It is a story about the fascinating chemistry of nitroglycerin…

Read more in the June 2018 issue of AUS-e-NEWS, AUS-e-TUTE's free quarterly newsletter for chemistry students and teachers.

Subscribe to AUS-e-NEWS at https://www.ausetute.com.au/ausenews.html

Naming Esters the IUPAC Way

IUPAC naming of esters is not a bit hard, it's just a bit different to the way you name other organic molecules.

Follow AUS-e-TUTE's step-by-step guide to :

• naming esters
• drawing the structure of ester molecules
• writing the molecular formula for ester molecules

and you'll be amazed at how easily you can name, and draw the structure of, esters.

Then, when you think you've got the hang of that, why not try our ester naming game?
Or, test your skill with our ester test.
Preparing for an exam? We've got you covered! You can use our ester exam to practice your exam technique before you sit your exam.
And remember, AUS-e-TUTE's test and exam questions come with immediate feedback to help you understand where you go wrong and help you get the next question right.

AUS-e-TUTE Members should log-in to use these new resources. 

Not an AUS-e-TUTE Member?
There is currently a "free-to-view" tutorial available at http://www.ausetute.com.au/namester.html

Find out more about AUS-e-TUTE membership at : http://www.ausetute.com.au/membership.html
and you can join AUS-e-TUTE at http://www.ausetute.com.au/register.html

Pthalate in Plastics

Researchers in the USA have found a link between premature births and the exposure of  pregnant women to a group of organic (carbon based) chemicals known as phthalates.

Phthalates have been used for more than 50 years as plasticizers, substances which are added to plastics to increase their flexibility, transparency, durability and longevity. For example, adding phthalates to polyvinyl chloride (PVC) makes the PVC soft and flexible, ideal for flexible plastic tubing. You will find phthalates in many products you come into contact with every day, from vinyl upholstery and floor tiles, to plastic food containers and wrappers, to personal care products like perfumes, moisturizer, and liquid soap.

Phthalates have the general structural formula shown below:

R and R' represent alkyl groups.
If R and R' are both CH₃ (methyl) groups, the molecule is known as dimethyl phthalate (abbreviated as DMP).
If R and R' are both C₂H₅ (ethyl) groups, the molecule is known as diethyl phthalate (abbreviated DEP).
When R and R' are very small alkyl groups, like methyl or ethyl groups, the phthalates are colourless, odourless liquids at room temperature and pressure.
The phthalates are added to molten plastic, allowing the phthalates to mix with with the polymer. The polar C=O groups in the phthalate molecules interact with partial positive charges on atoms in the polymer chain, for example, the C^δ+ of the C-Cl covalent bond in a polyvinyl chloride polymer.
When the plastic is cooled, the interactions between the phthalate and the polymer chains remain, and the alkyl groups of the phthalate screen the polymer chains from interacting with each other so that the polymer chains can slide over each other. This results in a more flexible plastic.


Reference:
http://www.abc.net.au/news/2013-11-19/common-plastics-chemical-linked-to-pre-term-births/5101828

Further reading:
Esters and Esterification
Bond Polarity
Intermolecular Forces


Suggested Study Questions:

1. Draw the structural formula for
   • dimethyl phthalate
   • diethyl phthalate
2. Give the molecular formula for
   • dimethyl phthalate
   • diethyl phthalate
3. On the structural formula for dimethyl phthalate, circle a benzene ring.
4. On the structural formala for diethyl phthalate, circle an ester functional group.
5. Dimethyl phthalate can be prepared in an esterification reaction using phthalic acid and methanol. Draw the most likely structural formula for phthalic acid. 
6. In chemistry, what is meant by a polar bond?
7. On the structural formula of diethyl phthalate,  show the partial charges of the atoms in the polar areas of the molecule.
8. Draw a diagram to show the interaction between dimethyl phthalate and a section of the polyvinyl chloride polymer.