caa a22 4500 606173277 CHVBK 20210128100732.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s11244-014-0342-0 doi (NATIONALLICENCE)springer-10.1007/s11244-014-0342-0 Reaction Mechanisms in the Direct Carboxylation of Alcohols for the Synthesis of Acyclic Carbonates [Elektronische Daten] [Michele Aresta, Angela Dibenedetto, Antonella Angelini, Imre Pápai] Dialkylcarbonates, (RO)2CO, can be prepared from alcohols and CO2. Such reaction is clean (water is the co-product) but thermodynamically disfavored. In principle, the reaction mechanism of formation of carbonates requires the acid-base activation of alcohols. Existing data support that the first step is the formation of the alkoxo group RO− that reacts with CO2 to give the hemicarbonate moiety ROC(O)O−. The latter converts into the relevant carbonate (RO)2CO following different pathways depending on the catalyst used. DFT calculations have been used in a few cases to support the reaction mechanism. Transition states relevant to various mechanistic scenarios have been identified. The results indicated that the relative energies of these transition states depend on the nature of the alkyl group and the molecularity of the reactive step. Organic catalysts, homogeneous-, heterogenized- and heterogeneous-metal systems are discussed in this paper and the known relevant mechanisms compared. Water represents a serious limitation to equilibrium shift to the right and can affect the catalysts. Techniques used to remove water are also discussed. Springer Science+Business Media New York, 2014 Organic acyclic carbonates nationallicence Alcohols carboxylation nationallicence Reaction mechanism nationallicence Water removal nationallicence Aresta Michele CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut Dibenedetto Angela CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut Angelini Antonella CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut Pápai Imre Research Center for Natural Sciences, HAS, Magyar Tudosok Korutja 2, H-1117, Budapest, Hungary aut Topics in Catalysis Springer US; http://www.springer-ny.com 58/1(2015-02-01), 2-14 1022-5528 58:1<2 2015 58 11244 https://doi.org/10.1007/s11244-014-0342-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11244-014-0342-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Aresta Michele CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut NATIONALLICENCE 700 1- Dibenedetto Angela CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut NATIONALLICENCE 700 1- Angelini Antonella CIRCC, Via Celso Ulpiani 27, 70126, Bari, Italy aut NATIONALLICENCE 700 1- Pápai Imre Research Center for Natural Sciences, HAS, Magyar Tudosok Korutja 2, H-1117, Budapest, Hungary aut NATIONALLICENCE 773 0- Topics in Catalysis Springer US; http://www.springer-ny.com 58/1(2015-02-01), 2-14 1022-5528 58:1<2 2015 58 11244