Li Fangxun

Li Fangxun

Li Fangxun (1902-1962) was born in Yizheng, Jiangsu Province. He is a physical chemist and educator, member of the academic department of the Chinese Academy of Sciences, and professor of Nanjing University.

In 1921, Li Fangxun was admitted to chemistry major of Jinling University; in 1925, he stayed in the university to teach; in 1928, he went to Northwestern University of the United States to study; in 1930, he returned to teach in Jinling university after receiving a doctor's degree; in 1947, he represented the Chinese chemical society to attend the 100th anniversary celebration meeting of British Chemical Society and the academic conference of International Federation of pure and Applied Chemistry; in 1948, Northwestern University of the United States invited him to give lectures in the United States and gave lectures He was appointed Vice President of Nanjing University in 1952; he was elected member of the academic department of the Chinese Academy of Sciences in 1955; he attended the 15th International Federation of pure and Applied Chemistry Academic Conference held in Portugal in September 1956 as the chief representative of the Chinese delegation; he persisted in his work after suffering from hypertension and heart disease in 1959; Li Fangxun was ill in 1962 He died in Nanjing on August 2. He was 60 years old.

Li Fangxun has been engaged in the research on the properties and theory of electrolyte solutions for a long time. He has made contributions to the reaction mechanism of Grignard reagent, the physicochemical properties of ions in aqueous solutions, such as ion entropy, ion polarization and radius, and ion activity coefficient in mixed electrolyte solutions. He has taught in Jinling University and Nanjing University for more than 30 years, and has cultivated a large number of talents for China.

Life of the characters

Born in Yizheng, Jiangsu Province on December 25, 1902.

In 1919, the revolution wave of the May 4th Movement swept across the country. Li Fangxun believed that the root of poverty and backwardness in old China was political corruption and backward science. Therefore, he is determined to use what he has learned to take the road of "saving the country by science" and "saving the country by education".

In 1921, he was admitted to Jinling University and chose to major in chemistry. He graduated in 1925 and stayed in the university to teach.

In 1928, he went to the Northwest University of the United States to study. In 1930, he received his doctorate. At that time, on the eve of the September 18th Incident, the Chinese people were in dire straits. In order to develop the cause of science and education in the motherland, he politely declined the retention of his tutor, resolutely returned to teach in Jinling University, and soon became the dean of the College of science. At that time, Li Fangxun was only 28 years old. Since then, he has been working in scientific research and education in his motherland for more than 30 years.

After the July 7th incident in 1937, North China fell and Nanjing was in danger. Jinling University moved to Chengdu. During the eight years of the Anti Japanese War, the KMT government suffered from political corruption and the people were in dire need of livelihood. In addition to the Japanese aircraft bombardment, not only the teaching was in trouble, but also many scientific research work was forced to stop. Li Fangxun's life is very poor, but with the strong support of his wife Professor Lin Fumei, he still makes use of all possible conditions to devote himself to teaching, scientific research and training postgraduates. As he said in the postscript of a paper, "during the Anti Japanese War, there was a lack of drugs and it was difficult to carry out experiments. Therefore, we must find a new way to find new relations from the data of previous experiments, to cause theoretical discussion, and to point out the way to carry out experiments in the future." In this way, based on his extensive theoretical knowledge, he continued his scientific research work with amazing perseverance. In order to consult the literature, he often walked between five universities in Chengdu. A large number of neat manuscripts record his meticulous academic attitude and assiduous spirit. Whenever there is an air raid, he always takes scientific research materials and pen and paper to hide in the air raid shelter to continue his thinking, calculation and writing. By systematically studying the physical and chemical properties of ions in electrolyte solution, a number of original results have been obtained. During this period, he published more than ten papers on hydration heat, hydration entropy, apparent volume, isotonic specific volume, polarization and radius, diamagnetism and susceptibility of ions. His scientific research achievements and perseverance to overcome difficulties are praised by peers at home and abroad.

In 1947, on behalf of the Chinese chemical society, Li Fangxun attended the 100th anniversary celebration of the British Chemical Society and the academic conference of the International Union of pure and Applied Chemistry (IUPAC), participated in various academic activities, and established friendship with world-famous scholars such as L. Pauling at that time.

In 1948, Northwestern University specially invited him to give lectures in the United States. In recognition of his outstanding contribution to the theory of electrolyte solution, he was awarded the honorary doctor of Science degree and the golden key in the same year.

In 1949, Li Fangxun once again declined the invitation of scientific research and teaching institutions in the United States and Australia, and firmly stayed in the motherland. At the same time, his wife, Lin Fumei, also declined the tutor's invitation to stay and overcame many obstacles to return from the United States to the embrace of the motherland.

Li Fangxun pursued progress in politics. Before the founding of the people's Republic of China, he was dissatisfied with the dark rule of the Kuomintang government, sympathized with the revolution, and actively supported and rescued progressive students many times under white terror. For example, in December 1935, the "129" student movement spread to Nanjing, and the progressive students of Jinling University responded. The school was surrounded by the Kuomintang army, and the situation was tense. Fearing no violence, Li Fangxun negotiated with eight professors to force the authorities to withdraw the army and protect the progressive forces in the school. In the previous student movements before the liberation of Nanjing, as the head of the school, he tried every means to cope with the suppression and search of the Kuomintang government. He was deeply cared and admired by patriotic teachers and students for his difficult situation and his actions to safeguard the revolutionary forces. After the founding of the people's Republic of China, he was deeply inspired by the prosperous scene of his motherland.

In 1952, Nanjing University merged with Jinling University, and Li Fangxun was appointed Vice President of Nanjing University. In addition to the teaching and scientific research work of chemistry, he also undertook the planning work of teaching and scientific research of the whole university.

In 1955, he was elected member of the academic department of the Chinese Academy of Sciences.

In September 1956, as the chief representative of the Chinese delegation, he participated in the 15th International Federation of pure and Applied Chemistry Academic Conference held in Portugal. When he found that someone was trying to create two Chinas, he immediately protested and led the delegation to withdraw from the meeting, thus defeating the plot against the new China.

He joined the China Democratic League in 1949 and served as a member of the Central Committee of the League since 1955.

In 1959, due to his long-term hard work, he suffered from high blood pressure and heart disease. However, he persisted in his work with indomitable perseverance.

On May 20, 1962, the anniversary of Nanjing University, he read a lot of literature and made a long special report entitled "sixty years of electrochemistry", from Arrhenius to the new progress of contemporary solution theory, from the foreign trends to the domestic situation, and looked forward to the future development of China. He won a warm welcome from the audience with his detailed materials and incisive arguments. But I didn't expect that this was his last public academic report. He died of myocardial infarction more than two months later.

Main achievements

Achievements in scientific research

Early engaged in Grignard reagent in non-aqueous solution reaction mechanism and electrolyte solution theoretical research, put forward the theory of ion hydration enthalpy and absolute entropy of hydration, used in the calculation formula of ion physical and chemical properties in aqueous solution, long-term cited by Monographs in this field. Since the 1950s, we have focused on the systematic study of mixed electrolytes, and measured the cell electromotive force of Grignard reagent in non-aqueous solution, which proved that Grignard reagent still has the characteristics of electrolyte in non-aqueous solution. The applicability of Harned rule to the calculation of ion activity coefficient in mixed electrolyte solution is verified, and a better formula is derived, which can be applied to mixed electrolyte solution with different ions.

Solution theory

As early as 1928, when he studied in the United States, he paid attention to some behaviors of Grignard reagent. At that time, Grignard reagent had been widely used in organic synthesis, but there were different opinions on the physical and chemical properties of Grignard reagent and the reaction mechanism. He made a systematic study of it. He measured the conductance of a series of Grignard reagents with different alkyl groups, listed the order of their conductance, studied the relationship between them and temperature, and found that the molar conductivity of ch3mgx decreased with the increase of temperature. At that time, some people used to electrolyze Grignard reagent, but due to the different electrodes used, the equipment was not perfect, and the products obtained were different from each other. Some people think that hydrocarbons such as ethyl should be formed on the anode, but they cannot be separated. Li Fangxun systematically analyzed and synthesized the previous work, elaborately designed a set of closed system to eliminate the interference of environment and air. He used platinum electrode, carefully collected and analyzed the products on cathode and anode, measured their decomposition voltage, thus clarified the possible structure of Grignard reagent, and proposed the reaction process on the electrode. He cooperated with W.V. Evans and others to publish five papers, which were published in the Journal of the American Chemical Society (JACS) from 1933 to 1935. Although this work was interrupted after returning to China, he instructed young teachers to study it again in 1958. Using amalgam electrode, he studied the electromotive force of the battery composed of Grignard reagent, analyzed the products on the electrode, deduced the reaction formula on the electrode, and confirmed that the Nernst formula was still valid in non-aqueous solution. On the basis of his previous work, from all angles, including electrolysis, conductivity, decomposition voltage, electromotive force of battery, etc