7/22/2012: Bleach

Now everyone is familiar or should be familiar (for those who don't clean) with bleach. Bleach is a chemical known for its cleaning capabilities and its ability to remove pigments or colour from objects, and its disinfectant ability.  Bleaching is a general form and consists of a couple different methods, but in particular I will be talking about the use of Sodium hypochlorite (NaOCl) being that it is the most popular.  The power of this chemical comes from it's oxidizing ability when it combines with water to make HClO, since it is a molecule of high electronegativity.  The oxidation process goes as follows 2HClO_(aq) + 2H⁺ + 2e^- → Cl_2(g) + 2H₂O . There has also been very extensive research in it's disinfectant process.  The first synthesis performed by Claude Louis Berthollet in 1789 is very simple where it consists of passing chlorine gas through sodium hydroxide: 

Cl_2(g) + 2NaOH _(aq)  → NaCl _(aq) + H₂O _(l)

07/12/2012 - Organolithium Ether Cleavage

There comes a point in a compound's life when there is a question of whether there is an easier way to make it, and in 1930 Karl Ziegler questioned this with organolithium compounds.  Not only did he find more simpler ways of preparing such organolithium compounds but he developed many applications for the use of the light metal.  The largest application of these compounds is in organic chemistry as organolithium reagents, used in creating those precious carbon-carbon bonds. But one of the first applications that Ziegler developed was the ability of Lithium to cleave an ether bond, demonstrated in the following reaction:

PhCH₂OMe + 2Li → PhCH₂Li + MeOLi

7/11/2012 - Generation of Alkyl Radicals

The next year in 1929 one of the pioneers of radio chemistry, Friedrich Adolf Paneth, an Austrian scientist who did the majority of his early work at Königsberg University, completed a journey set out by Sir Edward Frankland.  This discovery gained humanity the ability to create alkyl radicals, and the identification of such radicals through their ability to displace a metallic mirror (silver mirror etc.).  This was performed through the pyrolysis (thermal decomposition) of a lead organometallic with the general formula of PbR_4.

7/10/2012 - Beginnings of Carbonyl Chemistry

In 1928 a chemist by the name of Walter Heiber, also known as the father of carbonyl chemistry, started a systematic study of many metal carbonyls.  This allowed him to discover many of the hidden catalytic properties of these utilizable compounds.  Two of his most famous reactions were in the realm of Iron chemistry with the two following reactions:

Fe(CO)₅ + H₂NCH₂CH₂NH₂ →  (H₂NCH₂CH₂NH₂)Fe(CO)₃ + 2CO
Fe(CO)₅ + X₂ → Fe(CO)₄X₂ + CO

7/9/2012 - Synthesis of Tetraethyllead Pt. II

In the year of 1922 two chemists working with General Motors Corportation Thomas Midgley and T.A. Boyd discovered an additive to gasoline that would prevent engine knocking, meaning uncontrollable combustion.  This additive was Tetraethyllead, an organometallic discovered back in Germany in 1854 but not utilized until this point.  This great discovery 'lead' to the creation of new gasoline solutions which have since phased out due to the high toxicity of lead in the exhaust fumes.  The synthesis of Pb(C₂H₅)₄ is performed through the following reaction of a sodium lead alloy with chloroethane:

4NaPb + 4CH₃CH₂Cl → (CH₃CH₂)₄Pb + 4NaCl + 3Pb

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7/8/2012 - Synthesis of Polyphenylchromium Compounds

The past couple of days I have been recovering from my dentist reaching into my mouth and stealing my precious wisdom teeth, and dealing with my new found tolerance to most pain killers making it much more difficult than it should be.  But I have finally got my hands back on my organometallics text book so that I can continue in my history of organometallic chemistry.  I last left off in 1917 with the synthesis of Lithium alkyls, which then brings our journey to 1919 with a German chemist named Franz Hein.  This man's claim to fame came to him with the synthesis of polyphenylchromium compounds, being the first sandwich compounds to be made.  This synthesis was performed by the mixture of CrCl₃ (Chromium (III) Chloride) with PhMgBr (Phenylmagnesium bromide) to create a series of these phenylchromium salts that were later found to be made of biphenyl, not phenyl, and oriented in a way making them look like a sandwich.

7/5/2012 - Synthesis of Thioridazine

Thioridazine is a drug currently used as a treatment for Schizophrenia and other psychotic ailments.  The drug can also be used in the aid of people coming off of opiate withdrawal and insomnia.  After the synthesis the drug exists in the racemic form (meaning two molecules mirror images to one another), which in some cases can cause a problem (See Thalidomide), but in this case both molecules are of bio-medical importance.  The synthesis involves the combination of 2-methylthiophenothiazine with 2-(2-chloroethyl)-1-methylpiperidine through the alkylation of the nitrogen on the 2-methylthiophenothiazine by the addition of a weak base to deprotonate that nitrogen (in this case Sodium amide, NaNH₂) so that a substitution reaction can occur between the Cl and the N.

Source: Wikipedia

7/2/2012 - Synthesis of Geosmin

The scent of rain is a very familliar odour for most, but most of those people have no clue why rain smells and question why rain should smell at all, it's just water.  Well the smell doesn't come from the rain itself, but from the soil below it.  The molecule in this scent is Geosmin, which also makes soil smell the way it does.  It is synthesized by microbes in the ground and when the rain disturbs the soil, this molecule gets released into the air.  Now chemists have found a way for us to make this molecule without the help of our little friends in the soil.  It all begins with a simple condensation reaction with ethyl vinyl ketone, and 2-methyl-cyclohexanone in presence of sodium ethoxide (NaOEt) creating the second ring.  But now there is an extra ketone on that second ring, so a second step of a special reduction method is required.  This involves the addition of (CH₂SH)₂ with BF₃ to create a thioketal derivative, and then desulfurization with Raney Nickel.

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