Substituent effects in the mass spectra of some γ- and β-substituted methyl butyrates was written by Howe, Ian;Williams, Dudley H.;Kingston, David G. I.;Tannenbaum, Harvey P.. And the article was included in Journal of the Chemical Society [Section] B: Physical Organic in 1969.Product Details of 20637-09-6 This article mentions the following:
Results are presented (relative ion abundances, I.P. and A.P. measurements) to illustrate substituent effects in the mass spectra of some γ-and β-substituted methyl butyrates. It is argued that (i) “subdecompn. energy” ions and (ii) competition in the source with fast fragmentation processes are important factors influencing parent/daughter ion ratios, which are then rationalized in terms of the variation of these two factors with substituent. In certain cases a substituent effect on the energy of activation of the transition state is also invoked. The variation in parent/daughter ratios at different energies is explained in terms of relative A.P.’s and frequency factors. Mechanisms are discussed for the elimination of MeOH from M+ and for the McLafferty rearrangement. (I. P. and A. P. = ionization and appearance potential). In the experiment, the researchers used many compounds, for example, Methyl 4-(4-aminophenyl)butanoate (cas: 20637-09-6Product Details of 20637-09-6).
Methyl 4-(4-aminophenyl)butanoate (cas: 20637-09-6) belongs to esters. Esters perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Product Details of 20637-09-6
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics