59582-39-7Relevant articles and documents
Collision-induced Dissociations of Carboxylate Negative Ions from 2-Ethylbutanoic, 2-Methylpropanoic, and Pivalic Acids. An Isotopic Labelling Study
Stringer, Michael B.,Bowie, John H.,Eichinger, Peter C. H.,Currie, Graeme J.
, p. 385 - 390 (1987)
Deprotonation of Et2CHCO2H yields Et2CHCO21-.On collisional activation this ion forms CO2-., CH2=CH-, and MeCH=CH-.In addition, elimination of H. and Et. yield Et(R)C=CO2-. (R=Et and H, respectively).The elimination of Et. is not a simple cleavage but occurs by loss of H. from a methyl group followed by loss of ethene.The carboxylate ion also rearranges to ; this species decomposes to OH-, , and also eliminates the elements of C3H8 and CH4.All fragmentations have been studied using 2H and 13C labelling: for example it is proposed that loss of CH4 from occurs by a six-centre stepwise process in which the first step (formation of an incipient methyl anion) is rate determining.The collisional activation mass spectra of Et2CHCO2-, Me2CHCO2-, and Me3CCO2- are different, all showing characteristic decompositions.For example, all three ions eliminate methane; the mechanism is different in each case.
