Paul Walden
Encyclopedia
- For the DJ Paul Walden, see Guru JoshGuru JoshPaul Walden , commonly known as Guru Josh, is an English musician currently performing under his own stage name as Guru Josh. Guru Josh was an original music icon of the British post-acid house music scene in 1990, most recognised for his debut single "Infinity," initially released in 1989 on...
.
Paul Walden was a Latvian
Latvians
Latvians or Letts are the indigenous Baltic people of Latvia.-History:Latvians occasionally refer to themselves by the ancient name of Latvji, which may have originated from the word Latve which is a name of the river that presumably flowed through what is now eastern Latvia...
-German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
known for his work in stereochemistry
Stereochemistry
Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms within molecules. An important branch of stereochemistry is the study of chiral molecules....
and history of chemistry. In particular he invented the stereochemical reaction known as Walden inversion
Walden inversion
Walden inversion is the inversion of a chiral center in a molecule in a chemical reaction. Since a molecule can form two enantiomers around a chiral center, the Walden inversion converts the configuration of the molecule from one enantiomeric form to the other. For example, in a SN2 reaction,...
and synthesized the first room-temperature ionic liquid
Ionic liquid
An ionic liquid is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below some arbitrary temperature, such as . While ordinary liquids such as water and gasoline are predominantly made of electrically neutral molecules, ILs are largely made...
, ethylammonium nitrate
Ethylammonium nitrate
Ethylammonium nitrate or ethylamine nitrate is a salt with formula or ·. It is an odorless and colorless to slightly yellowish liquid with a melting point of 12 °C...
.
Early years
Walden was born in Rozula, Stalbe parishStalbe parish
- Towns, villages and settlements of Stalbe parish :*...
, Pārgauja municipality
Pārgauja municipality
Pārgauja municipality is a municipality in Vidzeme, Latvia. The municipality was formed in 2009 by merging Raiskums parish, Stalbe parish and Straupe parish the administrative centre being Stalbe.- References :...
in Latvia
Latvia
Latvia , officially the Republic of Latvia , is a country in the Baltic region of Northern Europe. It is bordered to the north by Estonia , to the south by Lithuania , to the east by the Russian Federation , to the southeast by Belarus and shares maritime borders to the west with Sweden...
in a large peasant family. At the age of four, he lost his father and later his mother. Thanks to financial support from his two older brothers who lived in Riga
Riga
Riga is the capital and largest city of Latvia. With 702,891 inhabitants Riga is the largest city of the Baltic states, one of the largest cities in Northern Europe and home to more than one third of Latvia's population. The city is an important seaport and a major industrial, commercial,...
(one was a merchant and another served as a lieutenant
Lieutenant
A lieutenant is a junior commissioned officer in many nations' armed forces. Typically, the rank of lieutenant in naval usage, while still a junior officer rank, is senior to the army rank...
) Walden managed to complete his education – first graduated with honors from the district school in the town of Cēsis
Cesis
Cēsis , is a town in Latvia located in the northern part of the Central Vidzeme Upland. Cēsis is on the Gauja River valley, and is built on a series of ridges above the river overlooking the woods below...
(1876), and then from the Riga Technical High School (1882). In December 1882, he enrolled into the Riga Technical University
Riga Technical University
Riga Technical University is located in Riga, Latvia.- Riga Polytechnical Institute, 1862-1918 :...
and became seriously interested in chemistry. In 1886, he published his first scientific study on the color evaluation of the reactions of nitric and nitrous acid with various reagents and establishing the limits of sensitivity of the color method to detection of nitric acid. In April 1887, he was appointed a member of the Russian Physico-Chemical Society. During this time, Walden started his collaboration with Wilhelm Ostwald
Wilhelm Ostwald
Friedrich Wilhelm Ostwald was a Baltic German chemist. He received the Nobel Prize in Chemistry in 1909 for his work on catalysis, chemical equilibria and reaction velocities...
(Nobel Prize in Chemistry
Nobel Prize in Chemistry
The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outstanding contributions in chemistry, physics, literature,...
1909) that has greatly influenced his development as a scientist. Their first work together was published in 1887 and was devoted to the dependence of the electrical conductivity of aqueous solutions of salts on their molecular weight.
Work in chemistry
In 1888, Walden graduated from the University with a degree in chemical engineering and continued working at the Chemistry Department as an assistant to professor C. Bischof. Under his guidance, Walden began compiling "Handbook of Stereochemistry" which was published in 1894. In preparation of this handbook, Walden had to perform numerous chemical syntheses and characterizations which resulted in 57 journal papers on stereochemistry alone, published between 1889 and 1900 in Russian and foreign journals 57 articles on the stereochemistry. He also continued his research in the field of physical chemistry, establishing in 1889 that the ionizing power of non-aqueous solvent is directly proportional to the dielectric constant. During the summer vacations of 1890 and 1891, Walden was visiting Ostwald at the University of LeipzigUniversity of Leipzig
The University of Leipzig , located in Leipzig in the Free State of Saxony, Germany, is one of the oldest universities in the world and the second-oldest university in Germany...
and in September 1891 defended there a master thesis on the affinity values of certain organic acids. Ostwald suggested him to stay in Leipzig as a private lecturer, but Walden declined, hoping for a better career in Riga.
In the summer of 1892 he was appointed assistant professor of physical chemistry. A year later he defended his doctorate on osmotic phenomena in sedimentary layers and in September 1894 became professor of analytical and physical chemistry at the Riga Technical University. He worked there until 1911 and during 1902–1905 was rector of the University. In 1895, Walden made his most remarkable discovery which was later named Walden inversion
Walden inversion
Walden inversion is the inversion of a chiral center in a molecule in a chemical reaction. Since a molecule can form two enantiomers around a chiral center, the Walden inversion converts the configuration of the molecule from one enantiomeric form to the other. For example, in a SN2 reaction,...
, namely that various stereoisomers can be obtained from the same compound via certain exchange reactions involving hydrogen. This topic became the basis for his habilitation
Habilitation
Habilitation is the highest academic qualification a scholar can achieve by his or her own pursuit in several European and Asian countries. Earned after obtaining a research doctorate, such as a PhD, habilitation requires the candidate to write a professorial thesis based on independent...
thesis defended in March 1899 at St. Petersburg University
Saint Petersburg State University
Saint Petersburg State University is a Russian federal state-owned higher education institution based in Saint Petersburg and one of the oldest and largest universities in Russia....
.
After that, Walden became interested in electrochemistry
Electrochemistry
Electrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
of nonaqueous solutions. In 1902, he proposed a theory of autodissociation of inorganic and organic solvents. In 1905, he found a relationship between the maximum molecular conductivity and viscosity of the medium and in 1906, coined the term "solvation". Together with his work on stereochemistry, these results brought him to prominence; in particular, he was considered a candidate for the Nobel Prize in Chemistry in 1913 and 1914.
Walden was also credited as a talented chemistry lecturer. In his memoirs, he wrote: "My audience usually was crowded and the feedback of sympathetic listeners gave me strength ... my lectures I was giving spontaneously, to bring freshness to the subject ... I never considered teaching as a burden".
1896 brought reforms to the Riga Technical University. Whereas previously, all teaching was conducted in German and Walden was the only professor giving some courses in Russian, from then on, Russian became the official language. This change allowed receiving subsidies from the Russian government and helped the alumni in obtaining positions in Russia. These reforms resulted in another and rather unusual collaboration of Walden with Ostwald: Walden was rebuilding the Chemistry Department and Ostwald has sent the blueprints of the chemical laboratories in Leipzig as an example. In May 1910, Walden was elected a member of the St. Petersburg Academy of Sciences and in 1911 was invited to Saint Petersburg
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
to lead the Chemical Laboratories of the Academy founded in 1748, by Mikhail Lomonosov
Mikhail Lomonosov
Mikhail Vasilyevich Lomonosov was a Russian polymath, scientist and writer, who made important contributions to literature, education, and science. Among his discoveries was the atmosphere of Venus. His spheres of science were natural science, chemistry, physics, mineralogy, history, art,...
. He remained in that position till 1919. As an exception, he was allowed to stay in Riga where he had better research possibilities, but he was traveling, almost every week, by train, to St. Petersburg for the Academy meetings and guidance of research. In the period 1911–1915, Walden published 14 articles in the "Proceedings of the Academy of Sciences" on electrochemistry of nonaqueous solutions. In particular, in 1914 he synthesized the first room-temperature ionic liquid
Ionic liquid
An ionic liquid is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below some arbitrary temperature, such as . While ordinary liquids such as water and gasoline are predominantly made of electrically neutral molecules, ILs are largely made...
, namely ethylammonium nitrate
Ethylammonium nitrate
Ethylammonium nitrate or ethylamine nitrate is a salt with formula or ·. It is an odorless and colorless to slightly yellowish liquid with a melting point of 12 °C...
· with the melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...
of 12 °C.
After 1915, due to the difficulties caused by the World War I, political unrest in Russia and then October Revolution, Walden had reduced his research activity and focused on teaching and administrative work, taking numerous leading positions in science. Due to the political unrest in Latvia, Walden had immigrated to Germany together. He was appointed as professor of inorganic chemistry at the University of Rostock
University of Rostock
The University of Rostock is the university of the city Rostock, in the German state of Mecklenburg-Vorpommern.Founded in 1419, it is the oldest and largest university in continental northern Europe and the Baltic Sea area...
where he worked until retirement in 1934. In 1924 he was invited back to the Riga, where he gave a series of lectures. He was offered leading positions in chemistry in Riga and in St. Petersburg, but declined. Despite his emigration, Walden retained his popularity in Russia, and in 1927 he was appointed as a foreign member of the Russian Academy of Sciences. Later, he also became member of the Swedish (1928) and Finnish (1932) Academies.
Late years
In his late years, Walden focused on history of chemistry and collected a unique library of over 10,000 volumes. The library and his house were destroyed during the British bombing of Rostock in 1942. Walden moved to Berlin and then to Frankfurt am Main where he became a visiting professor of the history of chemistry at the local university. He met the end of the World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
in the French Occupation Zone, cut off the Rostock University, which was located in the Soviet Zone, and thus left without any source of income. He survived on a modest pension arranged by German chemists, giving occasional lectures in Tübingen
Tübingen
Tübingen is a traditional university town in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, on a ridge between the Neckar and Ammer rivers.-Geography:...
and writing memoirs. In 1949, he published his most well known book on "History of Chemistry". He died in Gammertingen
Gammertingen
Gammertingen is a town in the district of Sigmaringen, in Baden-Württemberg, Germany. It is situated 18 km north of Sigmaringen....
in 1957 at the age of 93. His memoirs were published only in 1974.