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MARGINALIA

Döbereiner's Lighter

Roald Hoffmann

Döbereiner's Feuerzeug

Johann Wolfgang Döbereiner was born in Hof an der Saale in Germany in 1780. His beginnings were simple. He was largely self-educated, the son of a coachman. But Döbereiner's talents were recognized, and in 1810 he was appointed to a professorship in Jena. This town was in the Grand Duchy of Saxe-Weimar-Eisenach, a princely state under the administration at just that time of another Johann Wolfgang, namely Goethe. Goethe and Döbereiner had an extensive correspondence, inter alia dealing with the tarnishing of silver spoons in red cabbage and the composition of Mme. Pompadour's toothpaste. Goethe went to Jena to study analytical chemistry with Döbereiner. (A contemporary analogue would be if the present French Prime Minister Jospin took off a few weeks to learn about supramolecular chemistry with Jean-Marie Lehn at the University of Strasbourg. It would be good for Jospin, but . . . .)

Döbereiner did much interesting chemistry. For instance, he was responsible for noting an important regularity in the chemistry of the elements, that of triads, one of the forerunners of Mendeleyev's periodic table. And Döbereiner observed in 1823 that when platinum metal (in a finely dispersed form called platinum sponge), was exposed to hydrogen, much heat was generated. The platinum (Pt) in fact glowed red- to white-hot, and if more hydrogen were supplied, the hydrogen burst into a hot but nearly colorless flame.

Figure 1. SchematicClick to Enlarge Image

Within days Döbereiner turned this beautiful observation (which Davy had also made six years before on platinum wires) into a practical lamp. Figure 1 shows the design. One has a bottle that can be tightly sealed. In an open glass cylinder in that bottle hangs a piece of zinc (d). The bottle is filled with sulfuric acid (typically 25 percent sulfuric acid (H2SO4)). There is a controlled outlet from the glass bottle, the stopcock (e). The zinc (Zn) reacts with sulfuric acid, generating hydrogen gas in situ:

Zn + H2SO4 → Zn2+ + SO42- + H2

When the stopcock is opened, the H2 is directed through a thin tube (f) onto a bit of platinum sponge (g). A flame lights, essentially instantaneously. When the stopcock is closed, the flame goes out. More H2 is generated, but comes to a stop as gas pressure builds.

Döbereiner continued his research with the catalytic properties of platinum (the word "catalysis" was coined by Berzelius in 1836); he actually was the first to make a supported catalyst (a mainstay of industrial catalysis and automotive catalytic converters today) by shaping small balls of potter's clay impregnated with platinum. For his work Döbereiner needed great supplies of the precious metal, and a geopolitical footnote is in order here: Platinum originally came from Spanish colonial mines in the New World, and that is presumably Döbereiner's original source. Around 1824 major deposits were discovered in the Urals. How could Döbereiner, who was struggling desperately in his laboratory finances, get the precious white metal? Well, the Empress of Russia, Catherine the Great (1729–1796), was a German princess from the Duchy of Anhalt-Zerbst. There were close Russian-German ties throughout this period, and they continued until the first World War. In Döbereiner's principality, the wife of Carl Friedrich, the then heir to the Grand Duke, was Maria Pavlovna, the daughter of Czar Paul I of Russia. Platinum from the Urals came easily to Jena.

Figure 2. Döbereiner lighterClick to Enlarge Image

Döbereiner's lamp became a common way to light fires in industrial settings in the first half of the 19th century. Within five years of its discovery 20,000 lamps were in use in Germany and England. It entered the middle-class home as well. (Nothing like this could happen today; imagine the horror of today's risk-avoiding society at the thought of filling a lamp with sulfuric acid!) And when a utilitarian technology is accepted into society, it is culturally processed. What I mean is that it is clothed according to the prevalent aesthetics of the time. In 1829 a Berlin manufacturer could offer "… as a pleasant and useful Christmas present a lighting machine, outfitted with platinum, elegant, clean, and sturdily constructed, with Chinese and other decoration, insensitive to wetness and cold…." Figure 2 shows a household Döbereiner lamp of the 19th century.

In time the safety match, the cerium frictional spark source (see Primo Levi's Ce chapter in his Periodic Table), the cigarette lighter and the gas stove electronic lighter put Döbereiner's lamp into the museum.





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