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Ester is quite a random nomenclature for a compound derived from a parent acid and parent alcohol.

Is there any reasoning behind using the word 'ester' to name such compound (for memorising purpose)?

One explanation for such nomenclature I found is quoted below from this website

The word "ester" was coined in 1848 by German chemist Leopold Gmelin, probably as a contraction of the German Essigäther, meaning acetic ether.

But even then, how does 'acetic ether' has to do with anything about ester being a nomenclature for a compound derived from a parent acid and parent alcohol?

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    $\begingroup$ The thing you have to remember is that most of the 'simple' compounds and functional groups were discovered before the structures were figured out. The names, therefore, would have been descriptive based on some quirk of the chemical. As musicians and coders know, naming things can be hard. You look at the etymology of most early elements and compounds, the names tend to work out to 'smells bad' or 'green flame' or 'oil from Tolu' $\endgroup$ – Ingolifs Sep 21 at 2:22
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The term "Essigäther" is actually the German name for ethyl acetate i.e Essig = "vinegar" + Äther = "ether". "vinegar" becomes acetic, hence ethyl acetate becomes "acetic ether". (etymoline.com)

But, ethyl acetate is an ester. So, why is it named "acetic ether"?

According to Leopold Gmelin, ester was called "oxy-acids ether" or "ether of third type". The original German text is:

b. Ester oder sauerstoffsäure Aetherarten. Ethers du troisième genre.

Viele mineralische und organische Sauerstoffsäuren treten mit einer Alkohol-Art unter Ausscheidung von Wasser zu neutralen flüchtigen ätherischen Verbindungen zusammen, welche man als gepaarte Verbindungen von Alkohol und Säuren-Wasser oder, nach der Radicaltheorie, als Salze betrachten kann, in welchen eine Säure mit einem Aether verbunden ist.

which translates to:

b. Ester or oxy-acid ethers. Ethers of the third type.

Many mineral and organic acids containing oxygen combine with an alcohol upon elimination of water to [form] neutral, volatile ether compounds, which one can view as coupled compounds of alcohol and acid-water, or, according to the theory of radicals, as salts in which an acid is bonded with an ether. (italics mine)

You see the name "ether" was used to define an ester but this usage has become obsolete to avoid confusion.

Other compound classes originally named ethers

Gmelin reports in his 1848 Handbook of Chemistry that French chemists use the terms ether of the first, second and third type to refer to ethers, thio- and halo-alkanes, and esters, respectively. While the modern term ether refers to compounds with a specific functional group, the term ether was historically used to refer to a variety of volatile substances.

https://www.google.com/books/edition/Hand_book_of_Chemistry/U4sMAAAAYAAJ?hl=en&gbpv=1&bsq=Ethers%20du%20troisi%C3%A8me%20genre

The names ether and ester are currently used, while the name "afer" for the thio- and halo-alkanes has not caught on.

Source: https://www.google.com/books/edition/Hand_book_of_Chemistry/U4sMAAAAYAAJ?hl=en&gbpv=1&bsq=Ethers%20du%20troisi%C3%A8me%20genre

Reference

  1. Leopold Gmelin, Handbuch der Chemie, vol. 4: Handbuch der organischen Chemie (vol. 1) (Heidelberg, Baden (Germany): Karl Winter, 1848)
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    $\begingroup$ Esters are volatile, ethereal, just like ethers. $\endgroup$ – Karsten Theis Sep 20 at 3:16
  • $\begingroup$ Thanks for the answer. The translated text of the german quote you provided said 'Ester [is the] Ethers of the third type," would you know what is the second type of ether (if there is one)? $\endgroup$ – Bøbby Leung Sep 21 at 20:44
  • $\begingroup$ @BobbyLeung these are very archaic terminologies. Only Gmelin knows what is he referring to ;-) $\endgroup$ – Nilay Ghosh Sep 22 at 3:19
  • $\begingroup$ @NilayGhosh Second type of ether are haloalkanes like chloroform. $\endgroup$ – Karsten Theis Sep 22 at 17:38
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Just to add another resource besides the excellent find by Nilay, in Organic Chemistry, The Name Game, it mentions

ester from German Essigäther (acetic ether) an early name for ethyl acetate

The unabridged Oxford English Dictionary (by subscription only) also mentions that Gmelin called these compounds as napthas but later he changed it to ester.

H. Watts tr. L. Gmelin Hand-bk. Chem. VII. 190 Ethers du troisième genre. I formerly distinguished these compounds by the name of Naphthas produced by oxygen-acids (Naphthen durch Sauers[t]offsäuren erzeugt); but I now propose for them the term Ester.]

Naphthas referred to

naphtha was used in Latin and Greek for a flammable, volatile liquid derived from the distillation of coal tar.

So it sort of supports what Karsten is saying that the volatility of esters must have impressed Gmelin. Ethers is very volatile!

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    $\begingroup$ I updated the other answer to include an excerpt of the English translation of Gmelin's handbook where he talks about ethers of the first, second and third kind. $\endgroup$ – Karsten Theis Sep 22 at 17:52
  • $\begingroup$ Thanks Karsten, this was useful. $\endgroup$ – M. Farooq Sep 22 at 18:53

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