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September–November 2020

Why do they call it that?

A buzz went through the historians of chemistry virtual gathering in July when it was reported to the CHEM-HIST list that a number of supposedly reliable sources report that benzine (what we call ‘petrol’ and the Americans call ‘gasoline’) was named after Karl Benz (1844–1929), whose patent for the first automobile was granted in 1886. The Benz car had a four-stroke engine with just one cylinder and the fuel was indeed ‘benzine’, a hydrocarbon fraction that had been available since about 1860 and was mainly used as a cleaning product. This benzine was a coal-tar product with a specific boiling range. Within a few years, the name was also adopted for a petroleum hydrocarbon fraction with more-or-less the same boiling range. The next higher fraction was called kerosene or sometime kerosine.

This all seemed pretty straightforward but other contributors to the list said that there was a longer history to it. It started with Eilhard Mitscherlich (1794–1863), who sent a manuscript with the title ‘Ueber das Benzol’ to the Annalen der Pharmacie and it was published in early 1834. A footnote revealed, however, that the editor, Justus von Liebig, had changed the name benzin that Professor Mitscherlich had given to the dangerous (possibly ‘flammable’?) oil that he had obtained by dry distillation of calcium benzoate, to benzol. Liebig had done this, he said, to avoid confusion of the chemical nature of the substance with the alkaloids that had names ending in ‘in’ and to align it instead with existing nomenclature for the acid (Benzosäure) and benzoyl compounds. Since Liebig was ‘he who is to be obeyed’ in the 19th century, most people accepted his dictum but in French publications such as those of Kekulé, there continued to appear benzine. Maybe it was just an example of the well-known French resistance to all things Allemand.

The lead for my second nomenclature puzzle is a report published by RACI Proceedings in 1955 of a talk given to the Analytical Group of the New South Wales Branch. The speaker was F.H. Conaghan and the talk was about the use of ethylenediaminetetraacetic acid (EDTA), a complexing agent used in analytical chemistry ‘as a titrant in the volumetric determination of metals’. The end point in a titration was indicated by loss of the colour formed by an indicator with those metals ions that had not been gobbled up by EDTA.

EDTA featured strongly in Ben Selinger’s article in Chemistry in Australia, just a year ago, when he wrote about crabby chemicals (Sept/Oct 2019, p. 38). Ben didn’t mention titrations, but I guess that modern technologies like atomic absorption have swept away such primitive things as indicators that change colour, and maybe even burettes!

In his talk, Conaghan mentioned a number of indicators, but curiously not the o-nitrosophenols that were the subject of his 1956 PhD thesis at the University of New South Wales. The o-nitrosophenols were the centrepiece of a technical report written by Conaghan and published by his employer, the NSW Department of Mines, in the same year. The RACI report of Conaghan’s talk was entitled ‘The Use of Versenes in Chemical Analysis’ but ‘Versenes’ was not mentioned in the text. I guessed that it was a tradename for EDTA, and that turned out to be the case, but I had to dig a lot to satisfy my curiosity. A method for the synthesis of EDTA was patented by a German inventor in the 1930s and marketed as Trilon B. Other manufacturers had already begun to market it under various tradenames. The Bersworth Chemical Company in the United States, founded about that time by Frederick Charles Bersworth (?–1973), marketed the sodium salt as Versene. After the company expanded its range to various salts and derivatives of EDTA, they adopted the plural and in 1952 changed the company name to Versenes Inc. In late 1954, the company was purchased by Dow Chemical and they still use the Versenes tradename today. Bersworth stayed with his company, now a Dow subsidiary, to make inventions relating to complexing agents. He took out more than 100 patents, the last of them being granted four months after he died.

It’s a pity that we don’t have the romance of Benz-ine, and nor was there any trace of Bers-ene ... but I do wonder if there was a V-for-B substitution back there in the 1930s. Or could it have been EDTA versus metal ions?

Ian D. Rae FRACI CChem ( is a veteran columnist, having begun his Letters in 1984. When he is not compiling columns, he writes on the history of chemistry and is an editor of Historical Records of Australian Science.

A 1955 advertisement for Versenes Incorporated.

... ‘Versenes’ was not mentioned in the text. I guessed that it was a tradename for EDTA, and that turned out to be the case, but I had to dig a lot to satisfy my curiosity.

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