Braunschweig salmiak

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Johann Heinrich (left) and Christoph Julius Gravenhorst

Braunschweiger salmiak was a product of the chemical factory Gebrüder Gravenhorst , which was founded in 1759 by the brothers Johann Heinrich and Christoph Julius Gravenhorst in Braunschweig and started with the production of salmia ( ammonium chloride , chemical formula: NH 4 Cl) in Braunschweig in 1762 .

background

At that time, ammonium chloride was used in dyeing and tannery as well as in tinning , galvanizing and soldering . Until the first salmia factories were built in England and France , ammonium chloride was mainly imported from Egypt , where it occurs in natural deposits.

production method

Ammonium chloride was produced in the Gravenhorst factory from animal and human urine. The urea contained therein was decomposed by putrefaction processes and converted in a multi-stage manufacturing process with gypsum ( calcium sulfate ; CaSO 4  · 2 H 2 O) and common salt ( sodium chloride ; NaCl). When the solution was evaporated, first Glauber's salt ( sodium sulfate ; Na 2 SO 4  · 10 H 2 O) was deposited, then ammonium chloride.

The Glauber's salt produced as a by-product of salmiak production was sold under the trade names "Gravenhorst'sches Salz" and "Braunschweig'sches Salz" for pharmaceutical purposes, e.g. B. as a laxative , sold to pharmacies.

The crude product was carefully recrystallized to purify the ammonium chloride . A highly concentrated ammonium chloride solution was poured into perforated ceramic molds for crystallization. After crystallization, the ammonium chloride was obtained in a conical block, similar to a sugar loaf .

Salmiak in sugar loaf form was still called "Braunschweiger Salmiak" after the Braunschweig company was shut down in the early 19th century.

Opinions of contemporaries

Chemical factory of the Gravenhorst brothers
"Plan of the City of Braunschweig" by Albrecht Heinrich Carl Conradi around 1755.
The site of the chemical factory of the Gravenhorst brothers in Braunschweig city center.

"... the manufacture of salmiac from urine, as was done earlier by the Gravenhorst brothers in Braunschweig, spreads an unpleasant, suffocatingly pungent steam and smell in a wide area."

- Johann Anton Heinrich Nicolai : Floor plan of the medical police , 1835

"It has a pungent salty, urinary taste."

- Justus von Liebig : Handbuch der Pharmacie , 1843

literature

Individual evidence

  1. ^ Rolf Walter (Ed.): History of innovation: Income from the 21st working conference of the Society for Social and Economic History, March 30 to April 2, 2005 in Regensburg . F. Steiner, Stuttgart 2007, ISBN 978-3-515-08928-9 , p. 189.
  2. ^ Karl Gottlieb Heinrich Erdmann: Textbook of chemistry and pharmacology for physicians, thier physicians and pharmacists. Volume 1, von Veit, Berlin 1841, pp. 444-445.
  3. ↑ Ernst Horn: Handbook of practical drug theory for physicians and surgeons . 2nd edition, Oehmigke the Younger, Berlin 1805, p. 646.
  4. ^ Johannes Leunis: School Natural History - Third Part . 4th edition, Hahn'sche Hofbuchhandlung, Hanover 1870, p. 189.
  5. ↑ Christoph Schümann: The share of German pharmacists in the development of technical chemistry between 1750 and 1850 . Peter Lang, Frankfurt am Main 1997, p. 117, ISBN 3-631-48212-4
  6. ^ A b Justus von Liebig: Handbuch der Pharmacie . Volume 1, 5th edition, C. F. Winter, Heidelberg 1843, p. 245.
  7. ^ Johann Anton Heinrich Nicolai: Floor plan of the medical police . Nicolaische Buchhandlung, Berlin 1835, p. 401.