Biographical Memoirs Volume 46 (1975) / Chapter Skim
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12. Arthur Michael
12. Arthur Michael
Pages 330-367
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From page 331... ...
B Lamb, "Arthur Michael," Harvard University Gazette 38(1943)
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From page 332... ...
He returned to Berlin in 1876 for two years of study, and it was then that he began the execution and publication of his remarkably long series of brilliant and important researches. Hofmann was the outstanding organic chemist of Germany and his laboratory at that time was the focal point of the world for research in organic chemistry, and there Michael became acquainted with many of the future leaders in that field, among them Ira Remsen and our own Charles Loring Jackson.
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From page 333... ...
ARTHUR MICHAEL 333 research students and his private assistants worked with him in his laboratory at Newton Center, but during his later years, they carried on their experimental work at the Converse Laboratory, reporting at frequent intervals to Professor Michael at his home. Michael became Emeritus here in 1936, nineteen years after he had taken a similar status at Tufts College.
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From page 334... ...
Michael was passionately interested in the theories of organic chemistry; that is, the fundamental laws and the mechanisms which might explain the marvelous variety and
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From page 335... ...
He developed special conceptions of the nature of valence, the condition of unsaturated systems, and the forces involved in chemical reactions, and he formulated a principle according to which 'every chemical system tends to so arrange itself that the maximum of chemical neutralization is attained.' "While a few of Michael's collaborators learned to apply his method of reasoning, the Michaelian theories have had but little following, even though accorded the prominence of a special chapter in F Henrich's treatise on the Theories of Organic Chemistry.
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From page 336... ...
"Summarizing, we can say that Michael was a powerful theorist, a keen critic and a consummate experimentalist. Or perhaps with equal appropriateness we can in conclusion quote the citation opposite his name in American Men of Science describing his field of activity, which reads, "Investigations in organic chemistry bearing on its fundamental laws and theory." In a review of the Michael reaction published 112 years after the initial discovery, E
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From page 337... ...
Typical acceptors are ~,,8-unsaturated aldehydes, ketones, and acid derivatives. By extension of the original scope, the Michael reaction has come to be understood to include addends and acceptors activated by groups other than carbonyl and carboalkoxyl.
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From page 338... ...
The original corpuscles of matter were exclusively carriers of free chemical energy (convertible into less active chemical and physical energy) , and all of the bound chemical energy (only partially reconvertible into free energy)
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From page 339... ...
Michael proposed that the free chemical energy in two unlike molecules was converted in part into bound energy and heat, the stability of the double molecule being determined by the extent of this conversion. He represented the reaction between sodium and chlorine in the following manner, using dotted lines to represent the free energy and solid lines the bound energy of atoms.
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From page 340... ...
He then restated the second law in chemical terms: 'Every chemical system tends to arrange itself so that the maximum of chemical neutralization is attained.' "Michael applied this general theory in detail to organic chemistry. Molecular rearrangements, addition and substitution reactions, tautomerism, and stereochemical phenomena were among the aspects of organic chemistry included within his theory.
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From page 341... ...
By changing into the oxime, much of the free energy in the nitroso group is converted into bound energy and heat; hence, there has been formed a well neutralized substance. However, the nitro group has less free energy, and its oxygen is less capable of overcoming the bound energy holding the hydrogen to carbon in the methyl group.
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From page 342... ...
"The addition process meant that a substance was unsaturated, and unsaturated compounds have free energy potentially convertible into bound energy. His understanding of unsaturation in organic compounds was a consistent aspect of his general theory.
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From page 343... ...
Michael found experimentally that the isomeric addition products were present in a ratio of 3:1 of the primary to the secondary iodide. With BrC1 the two atoms were more nearly equal in electronegativity and more nearly equal amounts of the primary and secondary bromide were formed.
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From page 344... ...
addition will occur if the affinity of AC-BD is greater than that of CD, and the more readily and completely the larger the difference. In this process of addition not only the affinity of A to C and of B to D comes into action, but also that of A to D and B to C, and therefore the further possibility is presented, not only of the combination of AC-BD, but of AD-BC, and the latter in increasing proportion the nearer the two combinations AC-BD is greater than AD-BC approach one another.' Thus, the more closely two atoms of a molecule resemble each other in chemical affinity for a third, the more nearly equal will be the relative number of molecules of the two compounds formed.
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From page 345... ...
"Far from overthrowing the basic theory, Michael felt that his correction of it greatly strengthened stereochemistry and ensured that it would become a fully established part of organic chemistry. Where chemists such as Wislicenus had erred was in thinking that the stereochemical course of reactions could be represented by purely mechanical, geometric means; adequate understanding required the use of thermodynamic factors.
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From page 346... ...
Thus, a change in affinity relations had occurred, and the system, instead of rupturing a carbon-carbon bond, was converted by migration of the phenyl group and a hydrogen atom into a salt of benzilic acid with a large increase in entropy OK OK OH 1 1 1 C6H5 C COC6H5~ C C C6H5 1 11 1 OH o C6H5 "Michael was a critic of all purely mechanical interpretations of organic.reactions, such as Victor Meyer's steric hindrance concept and Baeyer's strain hypothesis. He experimentally showed that steric hindrance was very limited and was applicable to the esterification of substituted benzoic acids only when hydrochloric acid was used as a catalyst.
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From page 347... ...
formation. "Michael's speculations were an attempt to broaden and develop structural theory in organic chemistry.
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348 BIOGRAPHICAL MEMOIRS had the same end: the realization of the maximum increase in entropy, and a sound chemcial theory must have this fundamental law as a basis. He stressed the need for thermochemical and physico-chemical investigations in order to reveal the intimate connection between energy relations and chemical behavior and hoped that the union of thermodynamical principles with structural theory would lead to a more profound science of organic chemistry.
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Zur Kenntniss der aromatischen Sulphone.
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From page 350... ...
Ges., 14:110. Uber die Einwirkung von aromatischen Oxysauren auf Phenole.
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ARTHUR MICHAEL 1883 351 On the action of aromatic oxy-acids on phenols.
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From page 352... ...
Uber einen Zusammenhang zwischen Anilidbildung und der Constitution ungesattigter, Mehrbasischer, organischer Sauren. IT Rer ritsch rE`~m f~ec 1q 187\ Uber die einwirkung des Anilins auf die Brommalein- und Chlo~ fumarsaure.
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From page 353... ...
Chem., 35:257. ·— Uber die Addition von Natriumacetessig- und Natriummalonsaureather zu den Athern ungesattigter Sauren.
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From page 354... ...
Uber die einwirkung von Jodwasserstoffsaure auf die Krotonsauren.
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From page 355... ...
Uber die Addition von Natriumacetessig- und Natriummalonsather zu den Athern ungesattigter Sauren.
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From page 356... ...
Chem., 48:94. 1894 ·— Uber die Addition von Natriumacetessig- und reather zu den Athern ungesattigter Sauren.
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From page 357... ...
Ges., 29:1792. Zur Kenntniss der Additionsvorgange bei den Natriumderivaten von Formyl- und Acetessigestern und Nitroathanen.
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From page 358... ...
Zur Kenntniss der Substitution-vorgange in der Fettreihe.
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From page 359... ...
Ges., 38:2523. Zur Kenntniss der Vorgange bei der Synthesen mit Natrium Malonester und verwandten Verbindungen.
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From page 360... ...
Ges., 39:2785. Uber die Einwirkung von Salzsaure auf With V
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From page 361... ...
Uber den stereochemischen verlauf der Addition von Chlor zu Crotonsaure.
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From page 362... ...
Zum verlauf der intramolekularen Umlagerungen bei den Alkylbromiden und zur Frage der Ursacl~e des Gieichgewichtszustandes bei Unkehrbaren reaktionen.
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From page 363... ...
Uber den Mechanisms der Einwirkung van Brom auf Fettsaurechloride.
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From page 364... ...
Ross. Partition principles as applied to the structures of enolic sodium derivatives of 1,3-diketones and ,8-keto esters.
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From page 365... ...
The partition principle as applied to the structures of enolic sodium derivatives of ,8-diketones and ,8-keto esters.
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From page 366... ...
Solvent and peroxide effect in the addition of hydrogen bromide to unsaturated compounds.
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