Infrared spectra and chemical abundance of methyl propionate in icy astrochemical conditions

Abstract

We carried out an experiment in order to obtain the InfraRed (IR) spectra of methyl propionate (CH3CH2COOCH3) in astrochemical conditions and present the IR spectra for future identification of this molecule in the InterStellar Medium (ISM). The experimental IR spectrum is compared with the theoretical spectrum and an attempt was made to assign the observed peak positions to their corresponding molecular vibrations in condensed phase. Moreover, our calculations suggest that methyl propionate must be synthesized efficiently within the complex chemical network of the ISM and therefore be present in cold dust grains, awaiting identification.

Promoting CO2 Electroreduction to Acetate by an Amine-Terminal, Dendrimer-Functionalized Cu Catalyst

“… The degree of crossing-linking dendritic branches and functional terminals was controlled by the number of repeated synthesis cycles (Figure S1a), including full generations of -NH 2 -terminated dendrimers (i.e., G 1 -NH 2 , G 2 -NH 2 , G 3 -NH 2 , G 4 -NH 2 ) and half generation of the -OCH 3 -terminated dendrimer (i.e., G 3 -OCH 3 , Figure S1b). Fourier transform infrared (FT-IR) spectra (Figure S2) of both G 3 -NH 2 and G 3 -OCH 3 samples showed typical vibrations of N–CO bonds (1650 and 1557 cm –1 ) and amide-linked -CH 2 - (2834, 2838, and 2927 cm –1 ), assigned to the dendrimer branches. − The G 3 -NH 2 sample showed a broad vibration of -NH 2 (∼3285 cm –1 ), while the G 3 -OCH 3 showed vibrations of -COOCH 3 (2958, 1735, and 1443 cm –1 ) and C–CO bond (1362, 1358, 1328, 1048, and 846 cm –1 ). , …”

“…20−22 The G 3 -NH 2 sample showed a broad vibration of -NH 2 (∼3285 cm −1 ), 22 while the G 3 -OCH 3 showed vibrations of -COOCH 3 (2958, 1735, and 1443 cm −1 ) and C−C�O bond (1362, 1358, 1328, 1048, and 846 cm −1 ). 22,23 Those synthesized dendrimers were then functionalized onto the Cu nanoparticles via an electrochemical deposition approach (Methods in Supporting Information, Figure 2a), and they were designated as G 3 -NH 2 /Cu and G 3 -OCH 3 /Cu, respectively. X-ray diffraction of all the samples showed the dominant Cu(111) diffraction at 2θ of 43.3°(JCPDS No.…”

Methyl Acetate and Its Singly Deuterated Isotopomers in the Interstellar Medium

“…Recently, Sivaraman et al (2013Sivaraman et al ( , 2015 carried out experiments to find out the spectral behaviour of methyl acetate and methyl propionate in Vacuum Ultraviolet (VUV) and Infrared (IR) at various astrophysically rel-evant temperatures (from 10 K to sublimation of ice) in ultrahigh vacuum chamber. In between 110 K to 120 K, they found an irreversible phase change (from amorphous to crystalline form of methyl acetate ice).…”