Friedrich Reinitzer

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Friedrich Reinitzer

Friedrich Richard Kornelius Reinitzer (born February 25, 1857 in Prague , † February 16, 1927 in Graz ) was an Austrian botanist , chemist and discoverer of liquid crystals .

Life

Reinitzer was born in Prague in 1857 as the son of a railway clerk. From 1867 to 1873 he attended secondary school in Prague. In 1873 he began his studies at the chemical-technical college of the Technical University in Prague and at the German University in Prague . He graduated in 1877 and then became an assistant for general and analytical chemistry . From 1882 to 1888 he was assistant for botany at the Plant Physiological Institute of the German University in Prague. In 1883 he was at the German University of Technology in Prague for Silo and technical microscopy habilitation . In 1888 Reinitzer was appointed associate professor for botany, merchandise and technical microscopy. In 1891 he became an associate professor for agricultural chemistry at the German Technical University in Prague.

In 1895 he moved to Graz, where he attended the local Institute of Technology was appointed first associate professor and in 1902 full professor of botany, organic raw materials and technical teaching microscopy.

The chemist Benjamin Reinitzer (1855–1928) and the sculptor and chaser Alois Reinitzer (1865–1917) were brothers of Friedrich Reinitzer. Sigrid Reinitzer and Heimo Reinitzer were his grandchildren.

plant

The structural formula of cholesteryl benzoate

Reinitzer's most important achievement was the discovery of the liquid-crystalline phase. In 1888 Reinitzer experimented with ester derivatives of cholesterol . He obtained the cholesterol by extracting it from carrots . With the derivatives he hoped to get information about the structure of cholesterol. Previously, some scientists had already observed a clear change in color when various cholesterol derivatives melt. One of the compounds Reinitzer synthesized was cholesteryl benzoate , the benzoic acid ester of cholesterol, whose molar mass he actually wanted to determine. Reinitzer was also able to detect a color in the range of the melting point on the cholesteryl benzoate. What was new, however, was that although this substance had its melting point at 145 ° C , the melt was a relatively viscous and, above all, cloudy liquid. Further heating at 178.5 ° C. turned the cloudy liquid into a clear one. The process was reversible and reproducible on cooling. Further purification processes did not change the behavior of the substance either. Such alleged melting intervals can usually be observed with contaminated compounds; Pure substances, on the other hand, have a “sharp” melting point. Reinitzer did not know how to further interpret this phenomenon and consulted the Prague crystallograve Viktor Leopold Zepharovic . Even he found no explanation for this phenomenon and recommended Reinitzer that he should contact Otto Lehmann in Aachen. On March 14, 1888, Reinitzer wrote to Lehmann, who was then a private lecturer at the Kgl. Technical University of Aachen was. This was followed by an exchange of letters and samples - cholesteryl benzoate and cholesteryl acetate . When examining the so-called Reinitzer preparations , Lehmann found that, like the silver iodide he was investigating, they have a third phase between the liquid and solid phase. This phase shows, for example, a birefringence that is otherwise only observed in solids .

The correspondence between Lehmann and Reinitzer ended on April 24, 1888, and many questions remained unanswered. Reinitzer presented the results on May 3, 1888 at a meeting of the Chemical Society in Vienna, mentioning the contributions of Lehmann and von Zepharovic.

Reinitzer discovered three important characteristics of cholesteric liquid crystals in cholesterol esters :

  • The presence of two "melting points" (melting point and clearing point )
  • The reflection of circularly polarized light
  • The ability to rotate the direction of polarized light

Even if the year 1888 is considered to be the birth of liquid crystal research, the "flowing crystals" - the term was later coined by Otto Lehmann - remained a phenomenon with little practical application for almost 80 years. It was not until the beginning of the 1970s that electro-optical displays based on liquid crystals ( LCDs ) were first used in wristwatches, pocket calculators and the like. Another 35 years should pass before it is widely used in flat screen televisions.

Fonts

  • About the physiological importance of transpiration in plants. In meeting reports of the Academy of Sciences , Vienna, 1881.
  • Analysis of a vegetable fat. In meeting reports of the Academy of Sciences , Vienna, 1882.
  • About the components of the leaves of Fraxinus Excelsior. In monthly journals for chemistry , 3/1882.
  • About hydrocarotene and carotene. In meeting reports of the Academy of Sciences , Vienna, 1886.
  • Contributions to the knowledge of cholesterol. In monthly magazine for chemistry , 9/1888.
  • About the true nature of the rubber ferment. In Zeitschrift für Physiologische Chemie , 14 (5) / 1890, pp. 453-470, Strasbourg, 1890.
  • The concept of tanning agents and its relationship to plant chemistry. In lotus. , Volume 11, 1891.
  • About the cell wall-dissolving enzyme in barley. In Hoppe-Seyler's Zeitschrift für Physiologische Chemie , 23 (2), pp. 175–208, Strasbourg, 1897.
  • About mushrooms as nurses and nourishers for higher plants. In communications from the Natural Science Association for Styria , Graz, 1907.
  • On the history of liquid crystals. In Annalen der Physik , Volume 27, Episode 4, Leipzig, 1908.
  • About the enzymes in acacia gum and some other types of gum. In Hoppe-Seyler's Zeitschrift für Physiologische Chemie , Volume 61 (4/5), pp. 352-394, Strasbourg, 1909.
  • About the breathing of the plants. , Inauguration speech, Graz, 1909.
  • Reply regarding the enzymes of acacia gum. In Hoppe-Seyler's Zeitschrift für Physiologische Chemie , Volume 64 (2), pp. 164-168, Strasbourg, 1910.
  • Contribution to the knowledge of the structure of the flax and hemp fiber. In Archives for Chemistry and Microscopy , Vienna, 1911.
  • About the determination of lupulin in hops. In reports. the Austrian Society for Promotion d. chem. Ind. , 1889.
  • Occurrence and extraction of rubber milk. In communications from the Natural Science Association for Styria , Graz, 1912.
  • The resins as vegetable waste. In communications from the Natural Science Association for Styria , Graz, 1914.
  • Investigations into Siambenzoe. In the Archives of Pharmacy , Volume 252, Berlin, 1914.
  • Dextrin manufacture. In Lexicon of all of technology and its auxiliary sciences , Stuttgart, 1919.
  • Studies on the olive resin. In proceedings of the Academy of Sciences , Volume 133, Vienna, 1926.
  • The Extraction of Benzoin and Benzoin Pre-Resin. In Archives of Pharmacy , Volume 264, Leipzig, 1926.

literature

Individual evidence

  1. ↑ P. Laggner: Friedrich Reinitzer (1857–1927) - from the discoverer of liquid crystals to the fighter against the "cognac madness", in Karl Acham (ed.): Natural sciences, medicine and technology from Graz. Böhlau Verlag Vienna, 2007, pages 319–326. ISBN 978-3-205-77485-3
  2. ↑ O. Lehmann: Liquid crystals and colloids . In: Colloid Journal . tape 15 , no. 2 , 1914, ISSN  0368-6590 , p. 65-75 , doi : 10.1007 / BF01430610 .
  3. ^ Friedrich Reinitzer ( memento of February 22, 2008 in the Internet Archive ), University of Hamburg, accessed on February 14, 2008.
  4. ^ F. Reinitzer: Contributions to the knowledge of cholesterol. In: Monthly magazine for chemistry . Volume 9, 1888, pp. 421-441, doi: 10.1007 / BF01516710 .
  5. ↑ Functional materials ( memento of October 1, 2011 in the Internet Archive ), accessed on February 14, 2008.
  6. ^ German Future Prize 2003: Lighter, Brighter, Faster: Liquid Crystals for TV Screens ( Memento from June 29, 2013 in the Internet Archive ).
personal data
SURNAME Reinitzer, Friedrich
ALTERNATIVE NAMES Reinitzer, Friedrich Richard Kornelius (full name)
BRIEF DESCRIPTION Austrian botanist and chemist; Discoverer of the liquid crystalline state
DATE OF BIRTH February 25, 1857
PLACE OF BIRTH Prague
DATE OF DEATH February 16, 1927
Place of death Graz