000144594 001__ 144594
000144594 005__ 20250923084423.0
000144594 0247_ $$2doi$$a10.1038/s42004-024-01248-6
000144594 0248_ $$2sideral$$a139429
000144594 037__ $$aART-2024-139429
000144594 041__ $$aeng
000144594 100__ $$aMerino, P.
000144594 245__ $$an-Alkanes formed by methyl-methylene addition as a source of meteoritic aliphatics
000144594 260__ $$c2024
000144594 5060_ $$aAccess copy available to the general public$$fUnrestricted
000144594 5203_ $$aAliphatics prevail in asteroids, comets, meteorites and other bodies in our solar system. They are also found in the interstellar and circumstellar media both in gas-phase and in dust grains. Among aliphatics, linear alkanes (n-CnH2n+2) are known to survive in carbonaceous chondrites in hundreds to thousands of parts per billion, encompassing sequences from CH4 to n-C31H64. Despite being systematically detected, the mechanism responsible for their formation in meteorites has yet to be identified. Based on advanced laboratory astrochemistry simulations, we propose a gas-phase synthesis mechanism for n-alkanes starting from carbon and hydrogen under conditions of temperature and pressure that mimic those found in carbon-rich circumstellar envelopes. We characterize the analogs generated in a customized sputter gas aggregation source using a combination of atomically precise scanning tunneling microscopy, non-contact atomic force microscopy and ex-situ gas chromatography-mass spectrometry. Within the formed carbon nanostructures, we identify the presence of n-alkanes with sizes ranging from n-C8H18 to n-C32H66. Ab-initio calculations of formation free energies, kinetic barriers, and kinetic chemical network modelling lead us to propose a gas-phase growth mechanism for the formation of large n-alkanes based on methyl-methylene addition (MMA). In this process, methylene serves as both a reagent and a catalyst for carbon chain growth. Our study provides evidence of an aliphatic gas-phase synthesis mechanism around evolved stars and provides a potential explanation for its presence in interstellar dust and meteorites.
000144594 536__ $$9info:eu-repo/grantAgreement/ES/AEI/PID2021-125309OA-I00$$9info:eu-repo/grantAgreement/ES/AEI/TED2021-129416A-I00$$9info:eu-repo/grantAgreement/EC/FP7/610256/EU/Gas and Dust from the Stars to the Laboratory: Exploring the NanoCosmos/NANOCOSMOS$$9info:eu-repo/grantAgreement/ES/MCIU/RYC2018-024364-I$$9info:eu-repo/grantAgreement/ES/MICINN/AEI/CNS2022-135658$$9info:eu-repo/grantAgreement/ES/MICINN/CEX2020-001039-S$$9info:eu-repo/grantAgreement/ES/MCINN/EUR2021-122006$$9info:eu-repo/grantAgreement/ES/MICINN/FIS2016-77578-R$$9info:eu-repo/grantAgreement/ES/MICINN/FIS2016-77726-C3-1-P$$9info:eu-repo/grantAgreement/ES/MICINN/PGC2018-096047-B-I00$$9info:eu-repo/grantAgreement/ES/MICINN/RYC2020-029800-I$$9info:eu-repo/grantAgreement/ES/MICINN/RYC2020-029810-I$$9info:eu-repo/grantAgreement/ES/MINECO/CEX2018-000805-M$$9info:eu-repo/grantAgreement/ES/MINECO/MAT2017-85089-C2-1-R$$9info:eu-repo/grantAgreement/ES/MINECO/PID2020-113142RB-C21
000144594 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
000144594 590__ $$a6.2$$b2024
000144594 592__ $$a1.485$$b2024
000144594 591__ $$aCHEMISTRY, MULTIDISCIPLINARY$$b50 / 239 = 0.209$$c2024$$dQ1$$eT1
000144594 593__ $$aBiochemistry$$c2024$$dQ1
000144594 593__ $$aMaterials Chemistry$$c2024$$dQ1
000144594 593__ $$aChemistry (miscellaneous)$$c2024$$dQ1
000144594 593__ $$aEnvironmental Chemistry$$c2024$$dQ1
000144594 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000144594 700__ $$aMartínez, L.
000144594 700__ $$aSantoro, G.
000144594 700__ $$aMartínez, J. I.
000144594 700__ $$aLauwaet, K.
000144594 700__ $$aAccolla, M.
000144594 700__ $$aRuiz del Arbol, N.
000144594 700__ $$aSánchez-Sánchez, C.
000144594 700__ $$aMartín-Jimenez, A.
000144594 700__ $$aOtero, R.
000144594 700__ $$aPiantek, M.
000144594 700__ $$0(orcid)0000-0002-3260-9641$$aSerrate, D.
000144594 700__ $$aLebrón-Aguilar, R.
000144594 700__ $$aQuintanilla-López, J. E.
000144594 700__ $$aMendez, J.
000144594 700__ $$aDe Andres, P. L.
000144594 700__ $$aMartín-Gago, J. A.
000144594 773__ $$g7, 165 (2024), 10$$tCommunications Chemistry$$x2399-3669
000144594 8564_ $$s1736839$$uhttps://zaguan.unizar.es/record/144594/files/texto_completo.pdf$$yVersión publicada
000144594 8564_ $$s2689732$$uhttps://zaguan.unizar.es/record/144594/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000144594 909CO $$ooai:zaguan.unizar.es:144594$$particulos$$pdriver
000144594 951__ $$a2025-09-22-14:37:31
000144594 980__ $$aARTICLE