The word is derived from the Greek pheno ("I bear light") commemorating the fact that benzene was discovered by Michael Faraday in 1825 from the oily residue left by the illuminating gas used in London street lamps. (500-501)Rather poetic, isn't it? Unfortunately McMurry digresses at this point to discuss the ortho/meta/para system, but it would have been interesting to read a little more behind the unique linguistic history of naming aromatic compounds. Does anyone know about any of the others (for starters: toluene, styrene, aniline, cumene, xylene...)? Are there any other chemical naming systems that rouse people's linguistic interest?
Wednesday, April 23, 2008
Aromatic compound names
We discuss a lot of very exotic-sounding compounds in class but one of the distinctions that had eluded me so far this quarter was the difference between something containing a phenyl group and something containing a benzyl group. At last, I returned to the old college organic chemistry textbook (McMurry 6th ed.) and there it was: phenyl is C6H5 (aromatic ring) while benzyl is C6H5CH2 (aromatic plus an alkylic (?) carbon). The naming of aromatic compound still remains, to me, one of the most idiosyncratic naming systems in organic chemistry--it seems like the root word "benzene" almost never appears--and yet there must be a good reason behind words like "styrene" and "toluene". Take phenol/phenyl for instance. McMurry writes:
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4 comments:
I'm glad to know I'm not the only one who has trouble keeping all of those aromatic compound names straight!
A few minutes on Wikipedia revealed slightly less poetic origins for the names of styrene, toluene, and aniline - styrene and aniline are named after plants whose extracts they were isolated from (the styrax tree and Indigofera anil) and toluene is named after tolu balsam, a secretion from a Columbian tree, from which toluene was extracted.
There's tons of them out there. Take for example the polyamines--all of their names are related to where they were first isolated from (and they're much more interesting than plants) such as cadaverine, and putrescine. So yeah, putrefying flesh and bad breath.
How about the names of the amino acids - Alanine, Glycine, Cysteine, etc.; where did they come from?
And, why is an 'ester' called an ester?
Several amino acid names are derived from other chemical words: cysteine from the compound cystine, alanine from the word "aldehyde" plus the suffix -ine (the middle syllable is just filler), methionine, phenylalanine, isoleucine, etc. A few have more colorful histories. Asparagine and aspartic acid both derive from "asparagus", and tyrosine comes in part from the Greek word for cheese ("tyros") because chemists used to isolate it from cheese. Glycine and leucine are descended from the Greek words for "sweet" and "white". And valine was first isolated from valerian, a medicinal herb.
The word "ester" appears to be a fusion of two German words. The second half of the word is from the word for "ether", but the first is from Essig, meaning vinegar; so 'vinegar-ether'?
PS This is all from the online Oxford English Dictionary--the University has a free subscription: www.oed.com
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