Wilhelm Rudolph Fittig

Wilhelm Rudolph Fittig (December 6, 1835 in Hamburg, † November 19, 1910 in Strasbourg ) was a German chemist. Fittig discovered a process for the conversion of halobenzenes to alkylbenzenes. He synthesized the methacrylic acid and acetone from the pinacol, he clarified the structure of benzoquinone on.

Life and work

Rudolph Fittig was the son of a private school teacher in Hamburg. The living conditions were very modest, so that the young Fittig the age of 16 worked as a teacher at a private school. Fittig earned the money for the study at the Pestalozzi Foundation. 1856 Rudolph Fittig began a science degree at the University of Göttingen. On the advice of Traun he took courses in chemistry at Friedrich Wohler, in physics, botany and technology. In October 1858 Fittig finished his chemistry studies with a dissertation on About acetone at Limprecht. He worked with Friedrich Wöhler Friedrich Konrad Beilstein together as a teaching assistant. In August 1860, Fittig habilitated with a lecture about Auguste Laurent and Jean Baptiste Dumas and their influence on the theoretical organic chemistry.

Fittig soon wrote the textbooks outline of organic chemistry (Berlin 1863), Outline of Chemistry ( Inorganic Chemistry, Organic Chemistry (Leipzig 1871, 1873) ).

From 1865 onwards, gave Fittig together with Beilstein published the journal for chemistry. In 1866 was Fittig full professor in Göttingen, 1870 Fittig went to Tübingen. 1876 ​​was Fittig successor to Adolf von Baeyer at the University of Strasbourg. Here a new chemical laboratory was built under his auspices. 1895/1896 Fittig was elected Rector of the University. 1902 ended Fittig his teaching.

He is co named after him and after Adolphe Wurtz, Wurtz synthesis of hydrocarbons. Among his major discoveries include the molecular formula for fructose and glucose, as well as the chemical substances pinacolin and biphenyl.

Scientific work

In his work on the acetone in the acetone Limprecht Fittig treated with sodium and discovered a well crystallizable substance, which he called Para acetone. Staedler showed that this substance contained more hydrogen than the acetone, and named the substance due to its tabular crystals pinacone. The fabric was newly found that pinacol (2,3- Dimethylbutandiol ).

From the oxidation of toluene ( contaminated with a little xylene - where the oxidation product was detected in the work) with dilute nitric acid was Fittig the previously unknown toluic acid.

As a result of Fittig alkyl derivatives of benzene (whose structure was unknown at that time ) now have been sought. Since the Bromabkömmlinge of benzene could be easily produced which positional good differentiated by chemical properties ( boiling points, melting points ), it was advantageous to find a reaction to replace the bromine by an alkyl group (which is clearly detectable at an elementary analysis).

First, he tried to implement bromobenzene with cyanide - in the hope to get the benzonitrile. These experiments - unlike aliphatic bromine compounds - fell through.

He set it forth benzyl chloride and had it together with sodium to the bromobenzene act. He could replace the bromine of the benzene by a benzyl radical. Together with Bernhard Tollens presented Fittig with benzyl radicals now since ethylbenzene, butylbenzene. Followed by reactions of bromobenzene with sodium acetate and methyl iodide, ethyl iodide, propyl iodide, they received toluene, ethylbenzene, propylbenzene. This reaction is known in textbooks as Wurtz reaction. Fittig could also show that the homologous compounds chlorotoluene and benzyl chloride behave quite differently with respect to the reactivity (substitution, alkylation).

Also, due to extensive work on homologues of benzene from Fittig decided Friedrich August Kekulé von Stradonitz to publish his ideas about the structure of the benzene ring.

Between 1867 and 1870 Fittig and employees mono-, di -, tri- bromotoluene added to xylene, mesitylene, tetramethyl benzene. A graduate student in Göttingen, Otto Wallach, discovered that distinguished the Bromtoluole. A bromotoluene crystallized out in the cold, the others remained in solution. The xylene there are several positional isomers (ortho -, meta-, para- ). By oxidation and elimination of carbon dioxide, various positional isomers of xylene could be represented clearly. Also on oxidation to terephthalic acid, formation of the anhydrides were xylenes positional isomers can be distinguished. Based on this finding, the positional isomers on the benzene ring were (ortho, meta, para) are assigned.

Another important work of Fittig was the elucidation of the structure of quinone. First Fittig had simultaneously elucidated by Zincke the structure of anthraquinone. The proposed Fittig correct structure of the benzoquinone, however, still remained unproven for some time. The assembly position of the two keto groups (ortho, meta or para) was questionable. It was not until the formation of the oximes by H. Goldschmidt brought an unambiguous clarification.

Along with Bieber Fittig could fathom the end of the Perkin reaction in more detail. He showed that initially made ​​an aldol condensation and a dehydration. Also for the coumarin showed Fittig to the correct structure and mode of formation about the coumaric acid. He used in the Perkin reaction also successfully succinic anhydride instead of acetic anhydride.

Fittig and Easter Meier also cleared of phenanthrene on the structure of this compound and gave her name. Furthermore Fittig found the fluoranthene.

Fittig employees and also the lactones have discovered. The addition of hydrogen bromide to cinnamic acid or when heated Ethylcrotonsäure led to a release of carbon dioxide. According to the findings of E. Erlenmeyer, the bromine anion in β - position, the hydrogen cation in α -position outsourced to the carboxyl group. The neighboring carboxyl group substituted the bromide anion and forms a lactone. Fittig also discovered the methacrylic acid in this work. From this acid introduced G. Kahlbaum soon a flexible glass forth (Plexiglas ). For cinnamic acid could be represented in a similar way, the Distyrol.

Works

• Floor plan of Chemistry, 6th Ed Berlin 1863.
• Contributions to examine the additive behavior of the molecular heat, specially organic compounds, Göttingen 1900.