Cannizzaro

Italian chemist. He entered the medical school of the University of Palermo and initially became interested in biology. In 1845, he met physicist M. Melloni in Naples, and through an introduction he went to Professor R. Piria at the University of Pisa, where he became his laboratory assistant and decided to become a chemist. In 1847 he participated in the uprising for the Kingdom of Naples, but it failed, and he fled to Marseille. In the same year he went to Paris and continued his studies of chemistry in the laboratory of ME Chevreul. In 1851 he returned to Italy and became a teacher of chemistry, physics, and mathematics at the Collegio Nazionale in Alessandria. He subsequently served as professor at the University of Genoa (1855-1861), the University of Palermo (1861-1871), and the University of Rome (1871-1909). His experimental work was in organic chemistry, and he is famous for his discovery in 1853 of the production of benzoic acid and benzyl alcohol from benzaldehyde using potassium hydroxide (the Cannizzaro reaction). His greatest achievement in theoretical chemistry was the letter he wrote in 1858, "Outline of a Course in the Philosophical Science of Chemistry", which outlined elementary chemistry lectures at universities (it was published in a journal the same year and as a pamphlet the following year), in which he proposed a new method for determining atomic weights and an atomic weight system. Chemists in the first half of the 19th century acknowledged the existence of atomic weights based on the chemical atomism announced by J. Dalton, but there were differences of opinion about how to determine atomic weights, and people adopted different atomic weights, resulting in a state of confusion. He made a clear distinction between atoms, molecules, and equivalents, and consistently used Avogadro's hypothesis (the same number of gas molecules are contained at the same pressure, temperature, and volume) and Dulong-Petit's hypothesis (the product of atomic weight and specific heat is constant) to create an atomic weight system that was not inconsistent with physical data. This pamphlet was distributed at the first-ever international congress of chemists, held in Karlsruhe, Germany in 1860, and the paper, along with his speech in the assembly hall, had a profound influence on the young chemists who attended. DI Mendeleev and JL Meyer, discoverers of the periodic law, also attended and were greatly influenced by him. In politics, he was highly regarded as a moderate liberal, and participated in national politics as a senator.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

イタリアの化学者．パレルモ大学医学部に入学し，はじめ生物学に関心をもつ．1845年ナポリで会った物理学者M. Melloniの紹介で，ピサ大学のR. Piria教授のもとに赴き，その実験助手になり，化学者となる決心をする．1847年にナポリ王国へのほう起に参加したが失敗し，かれはマルセイユに逃げた．同年，パリに出て，M.E. Chevreul(シュブルール)の研究室で化学の勉学を続け，1851年イタリアに帰国し，アレッサンドリアのCollegio Nazionaleの化学・物理学・数学の教師になった．その後，ジェノア大学(1855～1861年)，パレルモ大学(1861～1871年)，ローマ大学(1871～1909年)の教授を歴任した．かれの実験的な仕事は有機化学で，1853年に発見した水酸化カリウムによるベンズアルデヒドからの安息香酸とベンジルアルコールの生成(カニッツァーロ反応)が有名である．理論化学上の最大の業績は，1858年に書いた大学における初等化学講義の概要を説明した手紙“化学哲学教程の概要”(同年雑誌に掲載され，翌年小冊子として出版)で，ここで新しい原子量決定法と原子量体系を提案した．19世紀前半の化学者たちは，J. Dalton(ドルトン)が発表した化学的原子論にもとづく原子量の存在は認めていたが，どのように原子量を決定するかについて意見の対立があり，人によって採用する原子量がまちまちで混乱状態にあった．かれは，原子と分子，当量の明確な区別をし，アボガドロの仮説(同圧・同温・同体積には同数の気体分子が含まれる)とデュロン-プティの仮説(原子量と比熱の積が一定)を首尾一貫して用いて，物理学的データに矛盾しない原子量体系をつくりあげた．この論文冊子は，1860年ドイツのカールスルーエで開催された史上初の国際化学者会議で配布され，同論文は議場でのかれの弁舌とともに，参加した若手化学者に多大な影響を与えた．周期律の発見者D.I. Mendeleev(メンデレーエフ)とJ.L. Meyer(マイヤー)も参加して，大きな影響を受けた．政界においても穏健な自由主義者として重きをなし，元老院議員として国政に参与した．

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