Chiral molecule formation in interstellar ice analogs: alpha-aminoethanol NH 2 CH(CH 3 )OH

Bossa

Marcellus

et al. 2010

A&A

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Context. The study of the chemical reactivity in interstellar ices in astrophysical environments is an important tool for understanding the origin of the organic matter in molecular clouds, in protoplanetary disks, and possibly, as a final destination, in our solar system. The laboratory simulations of the reactivity in ice analogs provide important information for understanding the reactivity in these environments. Here, we used these experimental simulations to trace some formation pathways of two nitriles, acetonitrile and amino acetonitrile, which are two potential precursors of amino acids in astrophysical environments. Aims. The purpose of this work is to present the first experimental approach for the formation of acetonitrile and amino acetonitrile in interstellar-like conditions. Methods. We use Fourier Transform InfraRed (FTIR) spectroscopy and mass spectrometry to study the formation at 20 K of acetonitrile CH 3 CN from VUV irradiation of ethylamine and of amino acetonitrile NH 2 CH 2 CN from VUV irradiation of ammonia: acetonitrile mixture. Isotopic substitutions are used to confirm identifications. Results. We demonstrate that acetonitrile can be formed at 20 K from the VUV irradiation of ethylamine with a yield of 4%. Furthermore, in presence of ammonia, at 20 K and under VUV irradiation, the acetonitrile can lead to the amino acetonitrile formation. These results suggest that acetonitrile and amino acetonitrile can be formed in astrophysical environments that are submitted to VUV irradiations.

Section: Astrophysical Discussionmentioning

confidence: 99%

Experimental investigation of nitrile formation from VUV photochemistry of interstellar ices analogs: acetonitrile and amino acetonitrile

Bossa

Marcellus

et al. 2010

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“…The amino alcohol might then dehydrate in the presence of an acid to produce the corresponding imine (Walch et al 2001). These data are strengthened by experimental results, which show that ammonia can condense onto either formaldehyde or acetaldehyde for the temperature range 50-100 K (Bossa et al 2009;Duvernay et al 2010) to form the corresponding amino alcohols. Furthermore, recent experiments on hexamethylenetetramine (HMT) formation suggest that the imine can be formed at 200 K in the presence of acid by dehydratation of the corresponding amino alcohols (Vinogradoff et al 2011).…”

Section: Introductionmentioning

confidence: 92%

Experimental investigation of aminoacetonitrile formation through the Strecker synthesis in astrophysical-like conditions: reactivity of methanimine (CH₂NH), ammonia (NH₃), and hydrogen cyanide (HCN)

Borget

Chomat

et al. 2011

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Context. Studing chemical reactivity in astrophysical environments is an important means for improving our understanding of the origin of the organic matter in molecular clouds, in protoplanetary disks, and possibly, as a final destination, in our solar system. Laboratory simulations of the reactivity of ice analogs provide important insight into the reactivity in these environments. Here, we use these experimental simulations to investigate the Strecker synthesis leading to the formation of aminoacetonitrile in astrophysicallike conditions. The aminoacetonitrile is an interesting compound because it was detected in SgrB2, hence could be a precursor of the smallest amino acid molecule, glycine, in astrophysical environments. Aims. We present the first experimental investigation of the formation of aminoacetonitrile NH 2 CH 2 CN from the thermal processing of ices including methanimine (CH 2 NH), ammonia (NH 3 ), and hydrogen cyanide (HCN) in interstellar-like conditions without VUV photons or particules. Methods. We use Fourier Transform InfraRed (FTIR) spectroscopy to monitor the ice evolution during its warming. Infrared spectroscopy and mass spectroscopy are then used to identify the aminoacetonitrile formation. Results. We demonstrate that methanimine can react with − CN during the warming of ice analogs containing at 20 K methanimine, ammonia, and [NH + 4− CN] salt. During the ice warming, this reaction leads to the formation of poly(methylene-imine) polymers. The polymer length depend on the initial ratio of mass contained in methanimine to that in the [NH + 4− CN] salt. In a methanimine excess, long polymers are formed. As the methanimine is progressively diluted in the [NH + 4− CN] salt, the polymer length decreases until the aminoacetonitrile formation at 135 K. Therefore, these results demonstrate that aminoacetonitrile can be formed through the second step of the Strecker synthesis in astrophysical-like conditions.

“…The non-detection so far of these compounds in the gas phase comes from the lack of rotational spectra for these molecules. From an astrobiological point of view, aminoalcohols are interesting molecules because they are considered as amino acid precursors in the Strecker synthesis (Bossa et al 2009b;Duvernay et al 2010;Vinogradoff et al 2011;Rimola et al 2010;Danger et al 2011). In our case the N-methylaminomethanol will form through the Strecker synthesis the corresponding amino acid, the sarcosine (Eq.…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

Formaldehyde and methylamine reactivity in interstellar ice analogues as a source of molecular complexity at low temperature

Vinogradoff

Duvernay

et al. 2012

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Aims. The aim of this work is to consolidate the knowledge of ice evolution during the star formation process by investigating the influence of thermal reactions as a source of molecular complexity in the ISM. In this study, we are interested in the thermal reactivity between two interstellar molecules, formaldehyde (H 2 CO) and methylamine (CH 3 NH 2 ) in water ice analogues. Methods. We used Fourier transform infrared spectroscopy, mass spectrometry, and B3LYP calculations to investigate the thermal reaction between formaldehyde and methylamine ( 14 N and 15 N) at low temperature in water ice analogues. Results. We demonstrate that methylamine and formaldehyde quickly react in water ice analogues for astronomically relevant temperatures and form N-methylaminomethanol CH 3 NHCH 2 OH. The measured activation energy of this reaction, 1.1 ± 0.05 kJ mol −1 (1.8 ± 0.08 kJ mol −1 with methylamine 15 N), allows the reaction to proceed in interstellar ices, when the ices are gently warmed, as it occurs in young stellar objects, in photo-dissociation regions, or in comets. Therefore, CH 3 NHCH 2 OH is likely to be found in these objects. This hypothesis is confirmed by numerical simulations that clearly show that the formation of N-methylaminomethanol is likely at low temperature. Isotopic experiments as well as photochemical studies have also been performed to better characterise the ice evolution induced by heat and ultraviolet radiation during star formation.