| brain activity log
11.04.2006 Tuesday 03:10 - benzene
I have been outside for a couple of hours: went to a local pub and had
a small Hoegaarden beer. The interesting thing is that the sheet of paper
that the barman put under the beer glass was a hexagon and everything that
follows sourced from there (and wikipedia, obviously). Yes, I know that I'm brain damaged :D
Benzene, C6H6, also known as PhH or benzol,
is an organic chemical compound that is a colorless and flammable liquid with a pleasant, sweet smell.
It is an additive in gasoline and also an important industrial
solvent and precursor in the production of drugs, plastics, gasoline, synthetic rubber, and dyes.
Benzene is a natural constituent of crude oil, but it is usually synthesized from other
compounds present in petroleum. Benzene is an aromatic hydrocarbon, and the second [n]-annulene ([6]-annulene).
The formula of benzene caused a mystery for some time after its discovery,
as no explanation had been found that could account for all the bonds - carbon usually
forms four single bonds and hydrogen one. The chemist Friedrich August Kekule' von Stradonitz
was the first to deduce the ring structure of benzene.
Benzene presents a special problem in that, to account for all the bonds, there must be
alternating double carbon bonds. Using X-ray diffraction, researchers discovered that all
of the carbon-carbon bonds in benzene are of the same length, and it is known that a
single bond is longer than a double bond. In addition, the bond length, the distance
between the two bonded atoms in benzene is greater than a double bond, but shorter
than a single bond. There seemed to be in effect, a bond and a half between each carbon.
This is explained by electron delocalization. One representation is that the structure exists
as a superposition of the forms below, rather than either form individually. This type of
structure is called a resonance hybrid.
In reality, neither form really exists. Delocalisation must be explained using a higher
level of theory than single and double bonds. This delocalisation of electrons is known
as aromaticity, and gives benzene great stability. This is the fundamental property of
aromatic chemicals that differentiates them from non-aromatics.
To reflect the delocalised nature of the bonding, benzene may be depicted as a circle
inside a hexagon in chemical structure diagrams.
In the 19th and early-20th centuries, benzene was used as an aftershave because of its pleasant smell.
Benzene was also used to initially decaffeinate coffee by German importer Lugwig Roselius in 1903.
Actually it is widely known that benzene is a carcinogen.
Benzene occurs sufficiently often as a component of organic molecules that there is a
Unicode symbol with the code 232C to represent it.
Many important chemicals are essentially benzene, with one or more of the hydrogen atoms
replaced with another functional group.
Toluene, also known as methylbenzene or phenylmethane
(C6H5CH3) is used in the preparation of
Trinitrotoluene, C6H2(NO2)3CH3,
widely known as TNT or Trytol.
Phenol, C6H5OH, also known under an older name of carbolic acid, has
antiseptic and anesthetic properties.
Benzoic acid (C6H5COOH) and its salts are used as a
food preservative, represented by the E-numbers E210, E211, E212 and E213. Benzoic acid inhibits
the growth of mold, yeast and some bacteria.
Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three benzene rings.
It is an organic semiconductor and is used as a scintillator for detectors of electrons and alpha particles.
Salicylic acid is toxic if ingested in large quantities, but in small quantities
is used as a food preservative and antiseptic in toothpaste.
The hydroxyl group (-OH) can be acetylated to form acetylsalicylic acid also known as Aspirine :)
Paracetamol is a common analgesic and antipyretic drug that is used for the relief of fever,
headaches, and other minor aches and pains.
You can clearly match the structure of the benzene ring in many other (more complex) chemicals.
However, I'll probably see the Hoegaarden logo on it from now on :D
10.04.2006 Monday 04:32 - diary
In fact this entry refers to Sunday 09.04. Just like 70% of the days
in the last 15 years, it happened to cross the midnight boundary.
My natural timezone is probably UTC-5 (called also EDT: Eastern Daylight Time).
The zone contains cities like New York, Philadelphia, Washington, Boston and Montreal...
Bex is running in the background and I'm drinking my fifth tea of the day.
Now it's clear why I can't sleep :D
Recently met Lorenzo Venza,
an old friend from the "garage band" days. He was the one of the few that decided to really
go the music way and move out of this silent city. He is an appreciated "virtuoso" guitarist now...
well done! :) He showed me a nice fingerpicking technique that I'll try to practise in the next months.
Giacomo and Roberto
gave me approximatively 50 hours of music to listen to... it will take some months :D
50% of the Siena population magically disappeared for the Easter holidays.
There are several projects running out of time and some new ones under the hood: I'm expecting
to do major work in this week. Two exams also await me. I'd need to reduce the hours
of sleep a bit more...
08.04.2006 Saturday 14:59 - airplane log
I've just seen a passenger (Meridiana ?) airplane flying very low over my house.
This is absolutely unusual since there are no airports for that class of planes
here around. The closest are Peretola, 90 km away from here and S.Giusto, 150 km.
It was flying so low that I could see the plane windows from here.
Very strange.
07.04.2006 Friday 14:54 - be afraid
...
You can't hold me down forever
What doesn't kill me makes me strong
...
"The edge" - Annihilator
:)
06.04.2006 Thursday 09:00 - targeting london
Rebooted.
Nice news from Iakko. Plan confirmed and finalized: we're tripping to London in late May.
The curious note is that the tube station near our hotel has been a target
of a recent terroristic attack. The probability of two consecutive terroristic attacks
on the same target is very low: we're in a statistically safe place :)
Yakuza Rules!
want more ?
... really ? :D
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