Poster

CO2 Forum, 3rd edition
5
mai
/
2014, Poster

Segarra Anna M. : Synthesis of dimethyl carbonate by carboxylation reaction catalyzed by hydrotalcites supported on silical lyogel

Anna M. Segarra (a) Jordi Llorca, Ausies , Francesc Medina,
a ) University Rovira i Virgili
Corresponding author email:  anamaria.segarra@urv.cat

Carboxylation reaction is thus a new, safe, eco-friendly and economic alternative way of valorizing CO2 for use in generating fine chemicals.

Some studies have reported on the heterogeneous carboxylation reaction because of the advantages of heterogeneous catalysts over their homogeneous counterparts. A recently published study reported that heterogeneous catalytic materials such as CeO2, SnO2 and pure and modified ZrO2 have catalyzed the direct synthesis of DMC directly from MeOH and CO2 in a batch reactor. However, the methanol conversion was around 1% [1-2]. Several studies have confirmed that the equilibrium of the reactions (Scheme 1) is largely shifted to the left and can reach equilibrium concentrations of alkyl carbonates of between 1% and 2% depending on the reaction temperature [3]. Nevertheless, when was used CeO2-ZrO2 as catalyst, and when the H2O was removed from the reaction system using 2,2-dimethoxy propane as dehydrated agent, the methanol conversion improved from 0.81% to 4.2% [4].

The authors suggested that the presence of both acid and basic sites is an important factor in selective DMC synthesis. The mixed Mg-Al oxides (HTO) derived from the calcination of HTs are known to exhibit both weak acidic and weak basic properties [5]. Silica lyogels (LGs) [6] are also appropriate materials for use as catalysts supports.

In this context, nonimmobilized and immobilized Mg-Al hydrotalcite-like materials on silica lyogel were prepared and activated by calcination to be tested as catalysts in the direct carboxylation reaction of methanol. The HTs supported on silica lyogel showed an important improvement and high stability in the direct synthesis reaction of DMC from CO2 and MeOH.

2014 - Segarra Anna M. - synthesis of dimethyl carbonate_schema_2

Figure. Carboxylation reaction of MeOH with LG-HTO in standard conditions.

 

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References:

  1. Yoshida, Y.Arai, S.Kado, K.Kunimori, K.Tomishige, Catal.Today 2006 115 95
  2. Aymes, D.Ballivet-Tkatchenko, L.Jeyalakshmi, L.Saviot, S. Vasireddy, Catal. Today 2009 147 62
  3. Dibenedetto, M.Aresta, A.Angelini, J.Ethinraj, B.M.Aresta, Chem Eur. J. 2012 18 10324 and references therein
  4. Tomishige, K.Kuminori, Applied Catalysis A: General 2002 237 103
  5. Asadullah, K.Fujimoto, K.Tomishige,J.Phys.Chem.B 2001 105 10653
  6. Pons, Ll.Casas, E.Estop, E.Molins, K.D.M.Harris, M.Xu. J. of Non-Cryst. Solids  2012 358 461