German organic chemist Kekule. This paper mainly studies the structure theory of organic compounds. I found a simplified structure of benzene in my dream, which is called Meitan.

1829 was born in darmstadt on September 7th. 1848- 185 1 entered the university of Giessen and studied architecture at first. Later, he was deeply attracted and inspired by Justus von Liebig, the master of chemistry, so he changed to chemistry, and actively and rigorously studied it in Justus von Liebig's laboratory, completed an experimental paper on amyl sulfate and its salts, and obtained a doctorate. 1875 was elected as a member of the Royal Society. 1877 President of Bonn University. 1867- 1869, Kekule published the idea of three-dimensional arrangement of atoms in his speeches "On the Structure of Salt" and "On the Structure of Toluene 1 3,5-trimethylbenzene", which pushed the concept of atomic valence from plane to three-dimensional space for the first time.

Chinese name: Kekule.

Friedrich Kekule

Nationality: Germany

Nationality: Germanic

Place of birth: darmstadt.

Date of birth: 1829 (ugly year) September 7th.

Date of death:1July 896 13.

Occupation: chemist

Graduate school: Giessen University

Main achievements: Kekule benzene.

Representative works: the structure of aromatic compounds; On the structure of Lai (1, 35- trimethylbenzene).

The life of the character

Kekule received his doctorate from Giessen University. He studied under the famous chemist Justus von Liebig and others. He has taught at the universities of Heidelberg, Ghent (Belgium) and Bonn.

Kekule wrote many things in his life. From 65438 to 0929, editor-in-chief Anschuetz published two volumes of Kekule materials in Berlin, including his life, work and papers.

Former President of Bonn University, President of German Chemical Society. Cultivate a group of outstanding chemists such as Bayer. 1895 was awarded the title of nobility by German Emperor William II.

Kekule was born in darmstadt on 1829. When he was in middle school, he knew four foreign languages and loved architecture since childhood. He is determined to be an excellent architect when he grows up.

18 years old, admitted to Giessen University with excellent results. This was the most famous university in Germany at that time, with a beautiful campus and a simple style of study. What is more proud of this university is that it also has a group of well-known professors, and students can choose their favorite professors without professional restrictions.

Kekule designed three houses for darmstadt before he went to college. At the beginning of his career, he was convinced that he had a talent for architecture. Therefore, after entering Giessen University, he chose architecture without hesitation and quickly completed more than a dozen compulsory courses such as geometry, mathematics, sketching and painting at an alarming rate.

When he was preparing to raise his ideal sail, an accidental event changed his life track.

This is the case of the Countess Herlitz.

Kekule attended the hearing of the case. In the Hessian court, he met the real arbiter of this case-the famous Professor Justus von Liebig. The professor has a ring in his hand. This is a priceless gem ring with two intertwined metal snakes, one is red gold and the other is platinum. It looks exquisite. Professor Justus von Liebig measured the composition of metal, then stood up slowly to face the impatient audience and said in a calm and firm tone:

"White is made of platinum, so-called platinum. The crime of the countess's servant is obvious, because platinum was only used in the jewelry industry from 18 19, but he insisted that the ring came to him from 1805. "

Clear logical analysis and conclusive experimental conclusions made the criminal finally confess the fact of stealing the ring. The trial of this case made Kekule sincerely admire the famous professor.

In fact, Kekule had already heard the name of Professor Justus von Liebig at Giessen University, and his classmates had repeatedly persuaded him to attend the professor's chemistry class, but he had no interest in chemistry and didn't want to spend his time on things he didn't want to do. Therefore, his understanding of the professor is limited to hearsay. This accidental contact made Kekule change his mind and decided to attend Professor Justus von Liebig's chemistry class. In class, Professor Justus von Liebig's relaxed manners, humorous language and extensive knowledge brought Kekule to a brand-new world, which was as beautiful as a dream, strongly attracted Kekule and aroused his great interest. From then on, Kekule often attended Justus von Liebig's chemistry class, and gradually he became fascinated with chemistry research. Soon, Kekule gave up architecture and decided to switch to chemistry. This move was resolutely opposed by his relatives, so he was once forced to transfer to a higher technical school in darmstadt. But he still firmly believes that his future is to engage in chemistry, and there is no other way. Shortly after entering the technical school, he became very close to Friedrich Modern Hall, a chemistry teacher who is famous for inventing phosphorus matches. Under the guidance of this teacher, Kekule conducted analytical chemistry experiments and mastered many analytical methods. When relatives learned that Kekule was determined not to give up chemistry, they had to allow him to return to Giessen University to continue his research. 1in the autumn of 849, he returned to Justus von Liebig laboratory to continue his analytical chemistry experiment. Justus von Liebig was deeply moved by the student's strong will. Under his guidance, Kekule embarked on the road of studying chemistry.

1849 autumn, this is an autumn full of temptation and harvest joy! After hard work, Kekule entered the chemistry laboratory in Justus von Liebig with excellent results.

People lament that the construction industry has lost an excellent designer, but they are surprised to find that a beautiful building stands in the virgin forest of organic chemistry!

In order to further study chemistry, with the support of his uncle, Kekule went to Paris to study at his own expense. Due to financial constraints, he can only maintain a very low standard of living in Paris. However, Kekule, who is full of energy, ignored these difficulties and just worked hard. He wants to seize every opportunity and every minute to fully absorb new French academic ideas and styles. One day, he learned from the bulletin board on campus that Charles Gillard, a famous French organic chemist, was teaching a course of chemical philosophy. He went to class at once. After class, he asked Jural some very important questions, which immediately attracted the attention of scholars. He was invited to the study by Zhilal to discuss together. They talked so speculatively that they forgot to eat. It was already late at night when he said goodbye to Gillard and walked home slowly. In Paris, Kekule lived a poor life. Running between classrooms, libraries and dormitories from morning till night every day. He gained a lot and mastered many new experimental facts and research methods. He seized every minute because he knew that the day of returning to China in the spring of 1852 was getting closer and closer.

The first chemical paper written by Kekule was his research results on amyl bisulfate. This academic paper was highly praised by experts such as Professor Will. After the paper was published, in June of 1852, the academic committee of the school decided to award Kekule a doctorate in chemistry.

Shortly after returning home, Justus von Liebig introduced Kekule to work in Adolf von plante's private laboratory for a period of time. Later, he came to work in the laboratory of John steinhaus in London. The main task of steinhaus Laboratory is to analyze various pharmaceutical preparations and study the methods of preparing various new drugs from natural substances (mainly plants). These jobs are tedious and exhausting every day, but Kekule studies them tirelessly without complaint. When I am free in the evening, I will discuss theoretical and philosophical issues in organic chemistry with my colleagues. They sat around and had a heated debate: the concepts of valence, atomic weight and molecule were controversial topics for many times.

Kekule paid special attention to the problem of valence. He repeatedly imagined that bivalent sulfur and oxygen were the same. Therefore, if appropriate conditions are met, oxygen in some oxygen-containing organic compounds should be replaced by sulfur atoms in the near future. His idea has been proved by experiments, from which Kekule thinks that the concept of "valence" of atoms can be used as the basis of a new theory. Atoms combine according to some simple law. He imagined the atoms of elements as tiny spheres, and the only difference between them was the size. Every time he closes his eyes, he seems to see these balls clearly. They are constantly moving. When they approach each other, they combine with each other. In steinhaus's laboratory, intense and monotonous work occupied almost all of Kekule's time, and many of his scientific ideas and new hypotheses were too busy to have time for in-depth thinking and experimental verification. Therefore, he is eager to return to Germany, even if he is a lecturer in a university, he can have time to do his own scientific research. 1in the spring of 855, Kekule left Britain for home. He visited some universities in Berlin, Giessen, G? ttingen and Heidelberg, but to his disappointment, so many places failed to let him find a suitable job. So he decided to be an associate professor in Heidelberg and give private lessons. His idea was supported by robert bunsen, a professor of chemistry at the University of Heidelberg. Kekule rented a house, used one as a classroom and the other as a laboratory. Funded by my uncle.

At first, only six people came to his lecture. But before long, the classroom was crowded with people. This has enabled Kekule to earn considerable income. And the number of interns who make appointments to work in his laboratory is increasing day by day. While giving lectures, he took interns to do experiments and used all his spare time to continue his research. The main topics are "type theory" of organic matter and "valence" of atoms, starting from London. Although the funds are insufficient, it is still possible to carry on the research.

The period when Kekule devoted himself to chemistry was the period when organic chemistry became the mainstream of chemistry. Organic chemistry is developing at an unprecedented speed: chemists have discovered the fact that a large number of organic compounds exist and synthesized many rare organic compounds artificially; Willer and Justus von Liebig put forward the gene theory; The establishment of type theory, French chemist, and so on.

This undoubtedly greatly enriches the knowledge of organic chemistry, but at this time, organic chemistry can't be compared with inorganic chemistry anyway, because the research of inorganic chemistry is guided by Dalton's atomism, but organic chemistry is not. Practice without theoretical guidance is bound to be blind and chaotic: to describe the structure of acetic acid, people use the expression 19. Who is right and who is wrong? Chemists hold their own opinions and do not give in to each other, and the field of organic chemistry is in chaos.

From 65438 to 0895, Kekule, an accomplished chemist, became a chemistry teacher at Ghent University. He focused on the carbon chain, the backbone of organic compounds, in the chemical laboratory of Ghent University. As we all know, carbon atoms in nature do not form material molecules alone like other inorganic elements, but form carbon chains hand in hand between carbon atoms. There are several carbon atoms in the short chain and hundreds of carbon atoms in the long chain.

Kekule realized that the carbon chain is constant and stable in chemical reaction through chlorination of acetic acid. Then, he used succinic acid, fumaric acid, maleic acid and other organic compounds to carry out a series of experimental studies to confirm. Soon, Kekule expressed his views on carbon chain and put forward the structure theory of organic compounds. He established the theory of carbon chain structure with C4 as the core. Kekule's theory was later developed and perfected by the famous Russian chemist Breitlev, and became a classic theory of the structure of organic compounds.

With the rapid development of organic chemistry, Kekule, a professor of system chemistry at Ghent University, thinks that the traditional textbook is out of date, and a new textbook of organic chemistry should be rewritten to meet the needs of new topics.

However, in the process of collecting information, Kekule deeply felt the confusion in the field of chemistry. In order to improve the theoretical unity of chemists, he came to Karlsruhe from Qiu Lai on 1859.

The purpose of Kekule's visit is to discuss with Karl Wei Qing Er, a professor of chemistry, the convening of a world conference of chemists. The main content of the meeting is to solve the different opinions of chemists on chemical valence, element symbols, atoms and molecules.

Kekule's idea was immediately echoed by the world chemical community.

1860 On September 3rd, the first World Congress of Chemists was held in Karlsruhe, Germany, and 150 chemists from more than ten countries attended the meeting. This meeting solved all the puzzling problems in inorganic chemistry, and it can be said that the expected purpose was achieved.

But Kekule, the initiator of the meeting, was not satisfied. Because inorganic chemistry dominated the meeting, his organic chemical structure was forgotten by most people. Perhaps organic chemistry is really a fierce and terrible virgin forest, as Weiler said.

Since 186 1, Organic Chemistry Course edited by Kekule has been published in a book. 1862 33-year-old Kekule married Stefanija, the daughter of the director of the lighting gas plant. A happy marriage doubled Kekule's strength, and he devoted himself to his work with greater enthusiasm. But unfortunately, the happy time is fleeting. The health condition of pregnant wife is worrying, which makes Kekule very anxious. As a result, the birth of a son sacrificed the mother's life. Kekule was immersed in infinite grief. How many relatives and friends comforted him, but failed to free him from the pain. It's just that his research work made him forget his misfortune temporarily and concentrate on studying benzene and its derivatives. In 1866, he drew a single and double bond space model of benzene, which is completely equivalent to the modern structural formula. 1896 In the spring, a severe flu broke out in Berlin. Kekule, who has chronic bronchitis, became more and more serious after being infected. On June 3rd of the same year, he passed away.

As an outstanding scientist, Kekule's achievements have been universally recognized all over the world. Academies in many countries have elected him as an honorary academician. His views are not only valued by scientists, but also often adopted by industrialists, and have been adopted since the19th century. The real authority of organic chemistry.

Personal realization

In the early years, Kekule developed type theory on the basis of predecessors' work, and thought that the nature of molecules was mainly determined by types, and tried to establish the overall type theory of organic matter. From 1857 to 1858, he proposed that carbon atoms in organic molecules are tetravalent and can combine with each other to form carbon chains, which laid the foundation of modern structural theory. His other great contribution is the paper "On the Structure of Aromatic Compounds" published by 1865, which put forward the cyclic structure theory of benzene for the first time. This theory has greatly promoted the development of aromatic chemistry and the progress of organic chemistry industry. It fully embodies the great promotion of basic theoretical research to technological and economic progress.

In the private class of Heidelberg (1856- 1858), Kekule synthesized many new substances with various chemical reagents and studied their properties. He paid special attention to the study of fulvic acid and its salts, hoping to find out their structures.

Kekule's research adds a new type-methane type to the original basic type of organic compounds. For example, if four hydrogen atoms of methane are replaced by monovalent groups, methane compounds can be obtained. In the article "On the Structure of Leimercury", he expounded the above conclusions. In Germany at that time, few chemists could understand and agree with Jural's and Aldrin's scientific thoughts, while Kekule supplemented and developed his type theory.

On the theory of atomic valence, Kekule published the article "Polyatomic Group Theory", and he put forward some basic principles. Some conclusions of frankland, Williamson, Aldrin and others are summarized, and the bonding force between atoms is deeply studied. How many atoms does he think one element has combined with one atom of another element? This number depends on the valence, that is, on the affinity between the components. He divided the elements into three categories:

Univalent elements-hydrogen, chlorine, bromine, potassium and sodium;

Bivalent elements-oxygen and sulfur;

The trivalent elements are nitrogen, phosphorus and arsenic.

In this way, Kekule expounded his views on valence. In this paper, he also pointed out that carbon occupies a special position among all chemical elements. Carbon is tetravalent in organic compounds because it combines with four monovalent hydrogen or chlorine to form CH4 and CCl4. However, carbon can also produce other hydrocarbons. Therefore, carbon-containing compounds need special study. His article "On the Composition and Transformation of Carbon-containing Compounds and the Chemical Properties of Carbon" not only demonstrates that carbon is tetravalent in organic matter, but also points out that Gjiral tries to summarize all chemical reactions with a universal principle-"double substitution" (or "binary substitution"). Practice has proved that Zhilal's theory is wrong, because some reactions directly synthesize one molecule from several molecules. In this paper, Kekule also used his brand-new ideas to examine the composition of organic groups. He wrote that for those substances containing several carbon atoms, it should be considered that the atoms of individual elements depend on the affinity (valence) of carbon for their existence in organic matter. Carbon primary carbon and carbon atoms are also combined with each other. At this time, the partial affinity (valence) of one carbon atom is saturated with the same affinity (valence) of another carbon atom. At that time, when most chemists didn't understand the essence of valence, the emergence of Kekule's above thought, that is, the new idea about carbon chain, was a revolution in the theory of organic compounds.

Kekule not only expressed his views on carbon chain, but also put forward the structural theory of organic compounds, pointing out that the general formula of saturated hydrocarbon is CnH2n+2. He also pointed out that if another substance is formed by simple transformation of a substance, it can be considered that the arrangement of carbon atoms in this compound is unchanged. When the transformation occurs, it only changes the position and type of other atoms except carbon atoms.

Kekule began to study the structure of benzene from 186 1. Kekule's benzene ring structure hypothesis has made outstanding contributions in the development history of organic chemistry. He was trained as an architect in his early years and has a certain ability of thinking in images. He is good at linking the properties and structures of compounds with model methods, and his painstaking research has finally achieved results. /kloc-in the winter of 0/864, his scientific inspiration made him make a major breakthrough. He once recorded: "I sat down to write my textbook, but my work didn't progress;" I am absent-minded. I turned my chair to the fire and fell asleep. Atoms jumped up before my eyes again, and smaller groups humbly retreated behind. Because of the constant appearance of this illusion, my thinking has become more acute. I can distinguish large structures of various shapes, and I can also distinguish long-line molecules that are sometimes close together. It spins, turns and moves like a snake. Look! What is that? There is a snake biting its tail, and this shape is spinning in front of my eyes. Like lightning, I woke up. I have been making this assumption all night. " In this way, Kekule satisfactorily wrote the structural formula of benzene for the first time. It is pointed out that the structure of aromatic compounds contains closed carbon atoms. It is different from aliphatic compounds with open chain structure.

The birth of benzene ring structure. This is a milestone in the development history of organic chemistry. Kekule believed that the six carbon atoms in the benzene ring were alternately connected by single bonds and double bonds to maintain the tetravalence of carbon atoms.