Who is the first father of chemistry

"Father of Modern Chemistry"

The words were supposed to precede his book "Organic Chemistry in Its Application to Physiology and Pathology" as part of a dedication, but Berzelius found them exaggerated and refused. Liebig shortened to “Dedicated to my friend J. J. Berzelius as a token of heartfelt affection and sincere respect”. By then the relationship between the two was no longer untroubled. A year later there was a break that even mediating friends could not undo.

Berzelius occupies a prominent position in the history of chemistry. Antoine Lavoisier and John Dalton had already developed a sign language for the chemical elements. Berzelius established a symbolic language based on the first letter of the Latin words and precisely determined a number of atomic and molecular masses. He developed a first model to understand electrolysis and discovered the elements cerium (also cerium), selenium and thorium. He presented other elements such as silicon, titanium and vanadium in pure form for the first time. He also used the term "organic chemistry" for the first time, and described and named phenomena such as isomerism and allotropy. Berzelius called the accelerated conversion of substances by an auxiliary substance discovered by Eilhard Mitscherlich and others as catalysis. The first volume of his “Textbook of Chemistry” appeared in 1808, further volumes followed. The work has been translated into numerous languages ​​and had a decisive influence on the development of chemistry in the 19th century.

Berzelius was born in 1779 as the son of a pastor. His father died of tuberculosis when he was four years old. The mother remarried, and Berzelius described his stepfather, Anders Ekmark, as a man of impeccable character who raised his wife's two children and his five children to observe nature. When Berzelius was nine years old, his mother died too, and he was raised by an uncle and guardian. After attending high school, he first studied medicine in Uppsala. At that time, the universities in Uppsala and Lund were still under strong spiritual influence and resisted the appointment of science teachers. In the field of chemistry, they contributed next to nothing. So Berzelius could not learn much from his teachers and essentially taught himself his knowledge and skills. After passing the physics course, he read with his stepbrother Christoph Girtanner's book “Beginnings of Antiphlogistic Chemistry” and familiarized himself with Lavoisier's theories. In his dissertation “Effects of Galvanic Electricity on Patients” (1802) he showed that galvanism, which was fashionable at the time, had no medical benefit for patients.

Until around 1775, the “phlogiston theory” prevailed in chemistry. According to her, the phlogiston, a hypothetical substance, escapes from all combustible bodies when burned and penetrates into them when heated. From the 1770s, Lavoisier and others refuted the phlogiston theory, and the role of the phlogiston shifted to oxygen: burns were now viewed as the association of combustible material with oxygen. Combustions with certain weight ratios result in oxygen compounds, so-called oxides, which react either acidic or alkaline. Acid and alkaline combustion products combine to form neutral compounds, the salts.

Two other significant discoveries made a decisive contribution to the further development of chemistry at the turn of the 19th century: the discovery of flowing electricity by Luigi Galvani and Alessandro Volta and the construction of the Voltaschen column, the first functioning battery. It was only this invention that enabled the use of electricity in chemistry and showed the close connection between chemical processes and electricity. Soon after the Voltasche invention became known, Berzelius manufactured a battery himself. Because silver was too expensive, he replaced it with copper. The function of the column was apparently not significantly impaired. In Jena, Johann Wilhelm Ritter changed the battery in the same way.

In 1802 Berzelius received an unpaid job as an adjunct in medicine and pharmacy at the Royal Collegium Medicum in Stockholm. It was not until 1807 that he became a professor there with an annual salary. Until then, he, who was not happy in business matters, had to rely on income from his work as a doctor for the poor. At first, Berzelius had no laboratory in Stockholm; but the mine owner Wilhelm Hisinger offered him an apartment in his house. It was here that the two of them carried out their first electrochemical experiments. They found that an alkali salt solution is broken down into an acid and a base by the voltaic column. Berzelius now assumed that all salts consist of a negative and a positive pole and are, as it were, small molecular magnets. In an electropositive particle the positive charge prevails, in an electronegative particle the negative charge. According to him, for example, potassium sulfate consisted of the electropositive KO and the electronegative SO3. According to Berzelius, the most electronegative substance was oxygen. His “dualistic theory” was only valid for about 20 years, but the terms “electropositive” and “electronegative” are still used today to denote polarized bonds in molecules.

From 1807 Berzelius experimented with the aim of “finding the definite and simple relationships according to which the components of inorganic nature are connected with one another”. At this point in time, Joseph-Louis Proust and John Dalton had already formulated the “law of constant proportions” and the “law of multiple proportions”. With Dalton, Berzelius assumed to explain these laws that matter is not infinitely mechanically divisible. He preferred the term “atom” for the smallest particles that could no longer be divided. He distinguished between atoms of simple and composite bodies. His experiments provided abundant evidence of the law of single and multiple proportions. Using precise analyzes, he calculated the percentage composition of inorganic compounds. This resulted in the atomic and molecular weights on the basis of the atomic and molecular theory. With his research he put “anti-inflammatory chemistry” on a solid basis.

His extensive analysis work was automatically linked to the desire to improve existing methods and invent new ones. Berzelius ’methods of separating substances from one another were considered the best of his time. Students like Heinrich Rose later developed it further.

From 1814 Berzelius included organic substances in his investigations. At that time, “organic” was the term used to describe substances found in plant and animal organisms, and it was assumed that they were produced by a mysterious life force. Today, by definition, organic chemistry includes all compounds of carbon with other elements; there are currently about 19 million known. Lavoisier had assumed that in inorganic nature all oxidized substances have a simple radical, while organic substances consist of oxides with compound radicals. Berzelius shared this view. A radical was understood to mean the atom or group of atoms that is bound to the oxygen in the oxygen compounds, "the oxygen-free remainder of a body". Sulfur and phosphorus, for example, were the radicals of sulfuric acid and phosphoric acid. In the case of vegetable substances, the radical should usually consist of carbon and hydrogen, and in the case of animal substances, it should also consist of nitrogen. By means of the "organic elemental analysis" it was possible to find out how many elementary components are present in an organic substance. To do this, it was completely oxidized, i.e. the carbon it contained was converted into carbonic acid and its hydrogen content into water. Nitrogen was released as a gas. The percentage of carbon, hydrogen and nitrogen could be calculated from the amount of each of these combustion products.

As important as Berzelius was as an empiricist and a practitioner, he attached great importance to theory and systematics at the same time: “The sciences always require a theory in order to bring our ideas into a certain order, without which the details would be too difficult to keep. Every theory is nothing more than a way of imagining the inside of phenomena, ”he wrote in his textbook. In doing so, he considered it a “reprehensible innovation to swap an already accepted type of explanation with another, the accuracy of which is not based on greater probability”. In 1822 Berzelius met Johann Wolfgang von Goethe and examined the Kammerbühl an extinct volcano with him. Berzelius explained to the poet how the soldering tube was used to investigate minerals. At the meeting of the naturalists in Hamburg in 1830, Berzelius met the 27-year-old Liebig and was so impressed that he invited him to an exchange of letters. The two only saw each other once, and Liebig's trip to Stockholm, which had been planned several times, did not materialize. Both valued each other very much, and yet from the mid-1830s onwards there was increasing alienation due to different theoretical views. Liebig disagreed with Berzelius' assumption of a "catalytic force" - in his view, it hampered scientific progress. And Berzelius refused to accept the substitution theory founded by Jean Baptiste Dumas in 1834 - the substitutability of hydrogen in organic compounds by, for example, halogens. He criticized corresponding experiments by Liebig and Friedrich Wöhler as well as the French researchers and tried to interpret them with the help of his electrochemical theory. In a letter to the Paris Academy, he opposed Liebig's assumptions, whereupon the latter publicly took a position against Berzelius. "(...) The reins have slipped out of his hand, he wakes up: the lion, whose teeth have become blunt, raises a roar over it, which no longer frightens a mouse," wrote Liebig in 1838 to Wöhler.

In 1835 Berzelius married Johanna Poppius, who was more than 30 years his junior and the daughter of a long-term friend. The marriage remained childless, but obviously did Berzelius good: "I'm fat and round like a provost and live very happily," he wrote to Wöhler. He traveled to Denmark several times with his young wife, but increasingly felt his strength waning: “But it is in the nature of things that everything goes downhill when you get old, and I am far from feeling sad about it (...) “, Wrote the 60-year-old to Wöhler. On August 7, 1848, Jöns Jakob Berzelius died in Stockholm at the age of 68.

 

literature

 

1. Hjelt E: History of Organic Chemistry. Wiesbaden: Springer Fachmedien 1916.

 

2. Melhado E: Jacob Berzelius. Stockholm: The University of Wisconsin Press 1981.

 

3. Prandtl W: Humphry Davy, Jöns Jacob Berzelius. Stuttgart: Scientific publishing company 1948.

 

Taken from MTA Dialog 12/2020