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Doctoral Thesis
DOI
10.11606/T.46.1974.tde-24052011-142944
Document
Author
Full name
Paulo Celso Isolani
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1974
Supervisor
Committee
Riveros, José Manuel (President)
Chaimovich Guralnik, Hernan
Jordan, Ivo
Qualifik, Paul
Toscano, Vicente Guilherme
Title in Portuguese
Formação e reatividade de íons negativos solvatados em fase gasosa por espectroscopia de ressonancia ciclotrônica de íons
Keywords in Portuguese
Íons negativos
Íons solvatados
Reações íon-molécula
Reações químicas
Ressonância ciclotrônica de íons
Abstract in Portuguese
A espectroscopia de ressonância ciclotrônica de íons foi usada para estudar reações de íons alcóxido, hidróxido, fluoreto, íon-radical óxido, acetileto e amideto com formiatos de alquila; o último íon reage também com N,N-dimetilformamida. Em todos os casos ocorre uma reação de descarbonilação, dando origem a um íon solvatado, que as evidências experimentais indicam ser unido por ponte de hidrogênio. Deslocamentos nucleófilos de grupos ligados ao esqueleto formílico podem ocorrer em casos adequados e em casos especiais ocorre ainda a formação de íons formiato. Os íons solvatados formados a partir de íons fluoreto e alcóxido com formiatos de alquila reagem com álcoois, podendo-se desta meneira estabelecer uma ordem de capacidade de solvatação para os álcoois alifáticos simples. A ordem estabelecida foi: CH3OH < C2H5OH < iso-C3H7OH < tert-C4H9OH. Foram determinadas constantes relativas de velocidade para as reações de vários íons negativos com formiatos de alquila, em sistemas onde se forma mais de um produto. Nos casos mais favoráveis (reações de íons fluoreto) foram calculadas constantes de velocidade absolutas para os vários canais de reação.
Title in English
Formation and reactivity of solvated negative ions in gas phase byion cyclotron resonance spectroscopy
Keywords in English
Chemistry reactions
Ion cyclotron resonance
Ion-molecule reactions
Negative ions
Solvated ions
Abstract in English
Ion-cyclotron resonance spectroscopy has been used to study the reactions between alkoxide, hydroxide, fluoride, O-, acetylide and amide ions with alkyl formates; the last ion reacts also with N,N-dimethylformamide. In all systems a decarbonylation occurs, giving rise to a solvated product ion, held by a hydrogen bond, as evidenced experimentally. Nucleophilic displacement of the formyl group substituents may occur in favorable cases and in a few particular systems the formation of formate ion is observed. The solvated ions formed through the reaction of fluoride or alkoxide ions with alkyl formates can react further with alcohols to establish the intrinsic clustering ability of simple aliphatic alcohols. The order of solvating ability is shown to follow the order CH3OH < C2H5OH < iso-C3H7OH < tert-C4H9OH. In systems where parallel reactions occur, relative rate constants were determined; in the most favorable cases (reactions of fluoride ions), absolute rate constants for the various reaction channels were calculated.
 
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Publishing Date
2011-05-24
 
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