Paul Friedländer (29 August 1857 in

Königsberg Königsberg (, ) was the historic Prussian city that is now Kaliningrad, Russia. Königsberg was founded in 1255 on the site of the ancient Old Prussian settlement ''Twangste'' by the Teutonic Knights during the Northern Crusades, and was named ...

– 4 September 1923 in

Darmstadt Darmstadt () is a city in the States of Germany, state of Hesse in Germany, located in the southern part of the Frankfurt Rhine Main Area, Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it th ...

) was a German

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

best known for his research on derivates of

indigo Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m ...

(for example

thioindigo Thioindigo is an organosulfur compound that is used to dye polyester fabric. A synthetic dye, thioindigo is related to the plant-derived dye Indigo dye, indigo, replacing two NH groups with two sulfur atoms to create a shade of pink. Thioindigo ...

) and isolation of

Tyrian purple Tyrian purple ( grc, πορφύρα ''porphúra''; la, purpura), also known as Phoenician red, Phoenician purple, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It is ...

from ''

Murex brandaris ''Bolinus brandaris'' (originally called ''Murex brandaris'' by Linnaeus and also Haustellum brandaris), and commonly known as the purple dye murex or the spiny dye-murex, is a species of medium-sized predatory sea snail, an edible marine gastr ...

''.

Life and work

Paul Friedländer was born as son of Ludwig Friedländer in Königsberg in 1857. The chemist

Carl Gräbe Carl Gräbe (; 24 February 1841 – 19 January 1927) was a German industrial and academic chemist from Frankfurt am Main who held professorships in his field at Leipzig, Königsberg, and Geneva. He is known for the first synthesis of the ec ...

was a regular guest of his father; thus after finishing the gymnasium, Friedländer studied chemistry in

in the laboratories of Gräbe. Later he studied at the

Strasbourg Strasbourg (, , ; german: Straßburg ; gsw, label=Bas Rhin Alsatian, Strossburi , gsw, label=Haut Rhin Alsatian, Strossburig ) is the prefecture and largest city of the Grand Est region of eastern France and the official seat of the Eu ...

and

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...

where he assisted

Adolf von Baeyer Johann Friedrich Wilhelm Adolf von Baeyer (; 31 October 1835 – 20 August 1917) was a German chemist who synthesised indigo and developed a nomenclature for cyclic compounds (that was subsequently extended and adopted as part of the IUPAC org ...

. He received his PhD for the work with Baeyer and completed his habilitation in 1883. He left the well-equipped laboratories of Baeyer in Munich in 1884 to work in the small company K. Oehler in Offenbach. In 1888, he became professor at the

University of Karlsruhe The Karlsruhe Institute of Technology (KIT; german: Karlsruher Institut für Technologie) is a public research university in Karlsruhe, Germany. The institute is a national research center of the Helmholtz Association. KIT was created in 2009 w ...

During a visit at his parents in Königsberg, he got engaged and married Martha Kobligk; they had three daughters. Although he liked staying in Germany, Friedländer accepted a position at the Technologische Gewerbemuseum in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

in 1895. During that time, he discovered the

. His research on the color variations in substituted indigoes yielded numerous patents and was applied in industrial production. Friedländer isolated and analyzed the

natural dye Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, and wood—and other biological sources such as fungi. Archaeol ...

stuff of

. He was able to obtain 12,000 ''

'' from biologists working at the Mediterranean sea. In a complicated process, he isolated 1.4 g of pure Tyrian purple. Contrary to his expectations, the compound did not contain

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

, but was a

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simila ...

substituted

, which had been already synthesized back in 1903. Friedlander was awarded the

Lieben Prize The Ignaz Lieben Prize, named after the Austrian banker , is an annual Austrian award made by the Austrian Academy of Sciences to young scientists working in the fields of molecular biology, chemistry, or physics. Biography The Ignaz Lieben Pri ...

for this discovery. In 1911, Friedländer abandoned his position in Vienna and joined the

Technische Universität Darmstadt The Technische Universität Darmstadt (official English name Technical University of Darmstadt, sometimes also referred to as Darmstadt University of Technology), commonly known as TU Darmstadt, is a research university in the city of Darmstadt ...

. The University was not far from the dye factories Chemische Fabrik Kalle, Höchst and

Cassella Cassella AG, formerly Leopold Cassella & Co. and Cassella Farbwerke Mainkur AG, commonly known as Cassella, was a German chemical and pharmaceutical company with headquarters in Frankfurt am Main. Founded in 1798 in the Frankfurt Jewish Alley by ...

that helped Friedländer in his research on dyes. In 1911, he was awarded the ''Adolf-von-Baeyer-Prize''. During

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

, Friedländer worked at the Kaiser Wilhelm Institute for Physical Chemistry and Elektrochemistry together with

Fritz Haber Fritz Haber (; 9 December 186829 January 1934) was a German chemist who received the Nobel Prize in Chemistry in 1918 for his invention of the Haber–Bosch process, a method used in industry to synthesize ammonia from nitrogen gas and hydrogen ...

. The poor living standards after the war affected his health, and after a trip in the summer of 1923 from Darmstadt to Biebrich, Friedländer had to stay in a hospital. His health problems gradually deteriorated and on 4 September 1923 he died in Darmstadt. The chemical reaction of

2-aminobenzaldehyde 2-Aminobenzaldehyde is an organic compound with the formula C6H4(NH2)CHO. It is one of three isomers of aminobenzaldehyde. It is a low-melting yellow solid that is soluble in water. Preparation and reactions It is usually prepared by reduction ...

s with

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...

s to form

quinoline Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only sli ...

derivatives, which Friedländer discovered in 1882, is today known as the

Friedländer synthesis The Friedländer synthesis is a chemical reaction of 2-aminobenzaldehydes with ketones to form quinoline derivatives. It is named after German chemist Paul Friedländer (1857–1923). This reaction has been catalyzed by trifluoroacetic acid, ...

References

{{DEFAULTSORT:Friedlander, Paul 1857 births 1923 deaths 19th-century German chemists 20th-century German chemists Scientists from Königsberg People from the Province of Prussia 19th-century German Jews University of Königsberg alumni University of Strasbourg alumni Ludwig Maximilian University of Munich alumni Academic staff of the Karlsruhe Institute of Technology Academic staff of Technische Universität Darmstadt