4/29/2012 - Synthesis of Lithium Alkyls

As I swerve back into the history of Organometallics I want to start back to 1917 in Germany.  A chemist named Wilhelm Schlenk, at the University of Munich, determined how to synthesize organolithium compounds through a Transalkylation process coupled with organomercury compounds.  He came up with two different methods of synthesis, one where there is nothing attached to the Lithium in the beginning and then the other method where there is an organic group that is transferred to the Mercury with a shorter alkyl group.  Both reactions are seen here below.

2Li + R₂Hg → 2LiR + Hg
2EtLi + Me₂Hg → 2MeLi + Et₂Li

The synthesis of the dimethylmercury (Me₂Hg) can be found here.


Source: 

The Immortality of Science

Here is a quote by Max Planck, touching on the subject of important scientific breakthroughs:

A scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.

To Describe is to Undescribe

Quantum mechanics is a peculiar subject to describe to someone who has very little knowledge of mathematics since most of the contents of the subject involve 'things' that have no visual analogies to the classical physics world we live in.  This topic has been orbiting around my mind ever since being introduced to the obscure topic, which told me that these particles can only be represented and understood through the mathematics that place foundation for theory.  For me as a student, whom had nothing more than the required mathematical background, it was difficult to pry myself away from my haunting visual of particles to grow solely dependent on the mathematics. This modern physics was the first to venture off into a realm of indescribability, where the physics could not be allegorical to anything built in our sensory system.  I am currently reading a biography on the quantum physicist Paul Dirac, who being a very quiet person already, only saying the most necessary words as if it was costly to say anything more than what was required, stated this very beautiful quote below, when his mother asked him to explain to her what he works on.  The beauty of this quote much relates to the philosophies described in Taoism, where all meaning is lost if one attempts to describe it through words.

“To draw its picture is like a blind man sensing a snowflake. One touch and it’s gone.”

4/18/2012 - How the Atomic Makeup of Water was Discovered

The question of how did someone could find out what is in water is a simple one, it basically consisted of combining hydrogen and oxygen together in a combustion to yield out water.  The scientist who carried out these experiments first was none other than Henry Cavendish, the British man to have the Cavendish Laboratory in Cambridge to be named after, of which many famous physicists go through, including Paul Dirac, James Maxwell, and Ernest Rutherford.  Now at that time, he had not named these gases as Hydrogen and Oxygen, but rather dephlogisiticated air and phlogiston respectively.  Phlogiston being the fire element that is released during combustion.  Through many experiments he determined that the greatest efficiency of water was obtained through the use of two parts hydrogen gas with one part of oxygen gas.  This was a very skeptical idea at the time that water was produced out of two invisible gases, but he endured many more of his experiments to prove his hypothesis, and win respect of the skeptics.

2H₂ + O₂ → 2H₂O + Heat

Source: Jaffe, Bernard. Crucibles: The Story of Chemistry. London, Hutchinson's scientific and technical publications, 1931.

4/17/2012 - The First Synthesis of Ammonium Chloride

The first recorded synthesis of this ammonium chloride compound was performed by Joseph Priestly, the minister responsible for my last post.  This was done while he was again experimenting with various gasses, and this time he was working with ammonia, seeing what would happen if he collecting a gas over mercury given off by ammonia water.  This gas was colorless, but contained the most pungent odor, so he took it even further by bringing the ammonia gas together with the hydrogen chloride gas.  This reaction produced a cloud, which after a while settled to form an odorless white powder.  He came to terms that this was something new when he analyzed it and noticed that there was no pungent odor from either the ammonia, nor the HCl.

NH_3(aq) + HCl_(aq) → NH₄Cl_(aq)

4/12/2012 - Creation of Soda Water

     In the late 18th century a Chemist by the name of Joseph Priestly, an self educated man living in Birmingham at the time, had an everlasting love for science and chemistry, so he decided to pursue science over his current ministerial work.  He was strong on the experimental method and had his scientific love focused on gases and the sources of the gas.  One day when he was at a public brewery he noticed the bubbles coming out of the vat and thought to himself what this gas was, so he decided to see what would happen if he would put a flame near these gases and observed that the flame extinguished after exposure.  So he collected this gas, and figured out a way to make it at home to analyze it, and little did he know that this gas was in fact carbon dioxide, CO2.  In one experiment he bubbled it through water and noticed that it was slightly soluble, and the water turned into an exceedingly pleasant sparkling water, very much like Seltzer water.  This was brought to the attention of the Royal Society and later became known as Soda water

4/10/2012 - Synthesis of Ethylene

     A very simple organic compound named ethylene, C₂H₄ was first synthesized by the ancient alchemist named Johann Becher. This compound of two carbons, containing a double bond was first synthesized by a process called ethanol dehydration where absolute ethanol is passed over a concentrated solution of sulfuric acid in the reaction C₂H₅OH + H₂SO₄ → C₂H₄ + H₂O +HSO₄. This compound later was introduced in 1922 as an anesthetic by Dr. Lockhardt, and is used today for hundreds of other purposes.

Beginnings of Chemistry: Paracelsus

   This post is a divergence from my usual reaction of the day, and more of a history lesson on one of the founders of what science is today, named Paracelsus.  Paracelsus was born in 1493 into an age of alchemy, where most men of that science were striving to turn anything into the valuable element of gold.  So naturally, as a man in love with the natural world, he would be immersed into the world of science (alchemy, medicine, astronomy, and botany).  In a lifetime of chasing this witchcraft and non scientific method of medicine, he finally had his epiphany in seeing that there were better methods in the science of medicine.  He found that it was better to search for drugs, to then prepare and purify them for use, than to use the previous methods of healing.  An example of this was that he was the first to make a tincture of opium, which was named by him laudanum, where he determined that the opium alkaloids were more soluble in alcohol than water and resulted in him making this laudanum solution.  At first people were skeptical of him because of his title as alchemist, meaning that he was related to the history of alchemists failing at producing gold.  Because of this he found it his mission to change peoples opinions of alchemy and science.  He gives a beautiful quote, that has much relevance still today for science skeptics:

"It's name will no doubt prevent its being acceptable to many; but why should wise people hate without cause that which some others wantonly misuse? Why hate blue because some clumsy painter uses it? Which would Caesar order to be crucified, the thief or the thing he had stolen? No science can be deservedly held in contempt by one who knows nothing about it.  Because you are ignorant of alchemy you are ignorant of the mysteries of nature."

     In changing the mission of the 16 century alchemist, he also set out to change the methods of the physician stating clearly that "if the physician were not skilled to the highest degree in alchemy, all his art was in vain".  With today's sciences we see clearly that he set future scientists in the right direction, and produce technology to better the human race.

Source:
Jaffe, Bernard. Crucibles: The Story of Chemistry. Hutchinson's Scientific and Technical Publications, London, 1931

Happy Easter From Chemistry

Here is a fun chemistry video on the contents of a creme egg.  There is nothing better than a holiday themed chemistry experiment.

4/4/2012 - What Makes Old Paper Yellow?

I apologize for once again another prolonged absence, for I have started physiotherapy and the pain has risen significantly, and writing a blog post was the least of my concerns.  I don't currently have my organometallic text book on me at this moment, so I thought I would diverge from the organometallic history for a moment to talk about paper.
If you have ever studied upon an old piece of paper, you would have noticed that the paper is no longer white but appears yellow.  If you were me, you would have had risen two questions, one, whether the paper was made in this tone, or two, whether some chemical reaction had been performed on the paper to make it this colour.  So I decided to look at what actually happens to the paper and have found that what makes it yellow is the formation of the molecules called Chromophores.  This process is done through the oxidation of cellulose over time creating many different products, but of most importance the aldehydic chromophores responsible for the yellowing.
Finding this information receives it's importance when researchers want to look into restoring old papers through a reduction process removing these chromophores.

Source: Science Magazine