Elsevier

Applied Catalysis B: Environmental

Volume 254, 5 October 2019, Pages 380-390
Applied Catalysis B: Environmental

Solvent-free synthesis of cyclic carbonates from CO2 and epoxides catalyzed by reusable alumina-supported zinc dichloride

https://doi.org/10.1016/j.apcatb.2019.04.024Get rights and content

Highlights

  • The first heterogeneous ZnCl2-catalyzed carboxylation of epoxides is presented.

  • ZnCl2/Al2O3-TBAI is efficient, cheap, easily prepared and applied catalytic system.

  • The reaction typically occurs under mild (60 °C, 4 atm) and solvent-free conditions.

  • The catalyst (ZnCl2/Al2O3) and nucleophilic additive (TBAI) have been reused in five cycles.

  • The catalyst also works in the reaction of epoxides with CS2 to form thiocarbonates.

Abstract

There is an ongoing interest to advance in the production of cyclic carbonates from carbon dioxide and epoxides under sustainable conditions. The ZnCl2/Al2O3-TBAI system has evinced to be a cheap, simple, readily accessible and reusable catalyst for the reaction of carbon dioxide with aromatic, aliphatic, cyclic and fluorinated epoxides with a low metal loading under solvent-free and mild conditions. This system has been also shown to be adequate for the reaction of epoxides with carbon disulfide to form the sulfur-containing cyclic carbonate analogs.

Introduction

Carbon dioxide is, among others (CO, CO2, CH4), the most appealing C1 carbon source because of being renewable, nontoxic, non-flammable, readily available and relatively inexpensive. It can be converted into fuels, materials and value-added chemicals by replacing other environmentally less benign substances with a lower E-factor impact [1]. It is a crucial building block for the synthesis of useful organic compounds [[2], [3], [4], [5]], being its reaction with epoxides [6,7] of paramount importance for the industrial preparation of carbonates (e.g., dimethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate and glycerol carbonate) [8,9] and polycarbonates [10]. Cyclic carbonates, apart from being present in natural products and potential pharmaceuticals, have found manifold applications in different disciplines; for instance, as electrolytes in lithium-ion batteries, as polar aprotic solvents and as synthetic intermediates [[11], [12], [13], [14]].

Besides being a 100% atom-economical process, the high thermodynamic stability of the CO2 molecule [15] makes the intervention of catalysts imperative for activating the implicated reagents [16]. Homogeneous catalysis and, to some extent, organocatalysis, dominate over heterogeneous catalysis, typically, in the presence of an ammonium salt [6,[17], [18], [19]]. A great advance in the field was made by North et al., who introduced the binuclear Al-salen [20,21] and salphen [22,23] complexes, together with a polystyrene-immobilized counterpart [24], as highly efficient catalysts for the carboxylation of terminal epoxides at room temperature and atmospheric pressure. Notwithstanding this research merit, the catalysts preparation requires multistep synthesis and the immobilized catalyst suffers from deactivation. Mononuclear Al-salen complexes [25] were shown to be also effective in the carboxylation of terminal epoxides, though higher temperature and longer reaction time were mandatory.

Lately, new catalytic systems have emerged with the aim to upgrade the performance of the epoxide−CO2 cycloaddition, namely: CaI2-(PEG DME 500) [26], CaI2-crown ether [27,28], tri-Co complex containing amine-bis(benzotriazole phenolate) ligands (in combination with TBAC) [29], highly active Al-aminotriphenolate [30] and Al-porphyrin based catalysts [31], Mn(II)-pyridin-4-yl-phosphonate MOF-TBAB [32], Ln(III)-coordinated polymers-TBAB [33] and La-heteroscorpionate-TBAB [34]. Notably, the formation of the cyclic carbonates could be accomplished not only in the presence of rather sophisticated complexes but also with simple catalysts such as MgCl2 (DMF, 100 °C) [35].

The combination of a ZnX2 Lewis acid catalyst with an ammonium salt has been also successfully exploited in the epoxide carboxylation [36]. For instance, TBAI with Zn-salphen [37,38], bis-(Zn-salphen) [39], Zn-azatrane [40], Zn-pyrrolidine [41] complex or Zn-MOF [42,43] allowed to carry out the reaction under mild conditions in good yields. The ammonium salt could be replaced with an ionic liquid [44] to furnish good yields with the assistance of a ligand-free zinc salt at 30 °C and 1 atm CO2 [45]. Ema et al. inserted an ammonium-fragment linker into zinc porphyrinate [[46], [47], [48]], with the resulting catalyst showing high TONs and TOFs, albeit under harsh reaction conditions (120 °C, 17 atm). A system based on the Zn cluster Zn4(TFA)6O-TBAI, insensitive to moisture and gaseous impurities, was effective under mild conditions (25 °C, 1 atm) but relatively longer reaction time was needed (up to 20 h) [49]. As an alternative to the activation of the epoxide, CO2 can be activated by N-heterocyclic carbenes (NHC) through the formation of NHC−CO2 adducts [50]; in this sense, the NHC-ZnBr2 system catalyzed the cycloaddition of CO2 to epoxides at atmospheric pressure (80 °C, DMSO) [51].

Metal-free organocatalytic systems look very attractive and green [18]. As recent examples, highly active cavitand-based polyphenol catalyst allowed to get good-to-excellent yields of both mono- and disubstituted carbonates in 18 h at 50 °C and 10 bar of CO2 in the presence of TBAI [52]; using squaramide derivatives, terminal carbonates were obtained in shorter time at higher temperature [53], whereas harsher conditions were necessary for internal epoxides. Alkyl ammonium and phosphonium salts themselves are active organocatalysts but they are difficult to recover and are deployed in quasi-equimolar amounts with respect to the substrate.

In spite of the fact of the good catalytic behavior manifested by the aforementioned catalysts, their homogeneous nature precludes reutilization and limits their practical application, especially of those involving tedious preparation procedures. In this vein, heterogeneous catalysis offers the possibility of catalyst recovery and reuse, hence making the whole process more sustainable [54]. Even though heterogeneous catalysts are characterized by a longer life than the homogeneous counterparts, the former have been much less investigated than the latter in the epoxide carboxylation, in part, because they are considered less active and require more severe conditions to reach a satisfactory yield. For instance, the silica/TBAB-catalyzed CO2-epoxide cycloaddition needed high catalyst loading, pressure (40 atm) and temperature (90 °C) [55]. Likewise, elevated temperature (100–140 °C) and pressure (10–45 atm) or prolonged reaction time (up to 48 h) had to be applied for ionic liquids [56] grafted onto different supports [[57], [58], [59], [60], [61]]. A CuII metal-organic hydrogel [62] and indium-based metal organic framework [63] worked under milder conditions but with modest-to-good conversions of the terminal epoxides (32–80%). Recently investigated, the heterogeneous catalysts based on three-dimensional copper-phosphate grid [64], APTES-modified zirconium oxide on MCM-41 [65], and cobalt-coordinated conjugated microporous polymer (Co-CMP-2) [66] allowed to attain high TONs and TOFs, but excellent yields were achieved only under relatively high pressure and temperature (80–100 °C, 10–30 at m). Several zinc-containing heterogeneous systems, such as a zinc complex with mesoporous o-hydroxybenzene polymers [67], a zeolitic imidazolate framework (ZIF-95) containing Zn atoms [68], a binuclear supramolecular zinc complex with hexadentate ligands [69] or Zn-Mg-Al composite oxides [70] have been reported; although all the catalysts were reused, at least, five times without significant loss of their activity, the reaction conditions were rather harsh (80–140 °C, 12–50 atm).

Concluding this introduction, we can say that there is a general upsurge of interest in developing sustainable catalysts [71,72] and reaction media [73] to promote the synthesis of cyclic carbonates from CO2 and epoxides under mild conditions [74]. In an ideal scenario, the catalytic systems should be simple, reusable for several cycles, without toxic reagents, and producing the cyclic carbonates in high yield and selectivity with a minimum generation of waste. In this context, we present herein our endeavor to adhere to these premises and introduce the heterogeneous catalytic system composed of ZnCl2 supported on alumina which, together with a catalytic amount of TBAI, catalyzes the epoxide carboxylation and thiocarboxylation in an efficient manner.

Section snippets

General

All starting materials were purchased from Sigma Aldrich and P&M-Invest (http://en.fluorine1.ru/) and were used without any further purification; solvents were dried and deoxygenated using standard procedures. Carbon dioxide gas of 99.99% purity was used. The carboxylation reactions were performed in a 15 mL-capacity glass low-pressure reactor RLP25ML (http://www.openscience.ru) equipped with a gas feeding system, magnetic stirrer and manometer. The NMR spectra of all products were recorded on

Results and discussion

The reaction of styrene oxide 1a with CO2 was used as a model reaction to gauge the activity of different Lewis acids (LA) under the following conditions: 0.6 mol% LA, 1.6 mol% TBAI as nucleophilic additive, 60 °C, 4 atm, neat (Fig. 1). The highest yields were recorded using zinc(II) bromide and chloride. It is known that NbCl5 can perform well in this reaction [75,76]; however, its catalytic activity (FeCl3 behaved similarly) was found to be inferior to that of the zinc salts under the above

Conclusions

The results of this study suggest a new avenue for research on epoxide carboxylation based on heterogeneous catalysis: the first heterogeneous ZnCl2-catalyzed carboxylation of epoxides in the presence of a tetrabutylammonium halide has been presented. A thorough comparison of the activity of different Lewis acids and their supports led to the conclusion that ZnCl2/Al2O3 was the catalyst of choice for the title reaction because of being efficient, cheap and easily prepared and applied. When

Acknowledgments

This study was generously supported by the Russian Science Foundation [project no. 14-23-00186 P], the M. V. Lomonosov Moscow State University Program of Development, the Spanish Ministerio de Ciencia, Innovación y Universidades [MICIU; grant no. CTQ2017-88171-P] and the Generalitat Valenciana [GV; grant no. AICO/2017/007].

References (104)

  • M. Aresta et al.

    Catalysis for the valorization of exhaust carbon: from CO2 to chemicals, materials, and fuels. Technological use of CO2

    Chem. Rev.

    (2014)
  • T. Sakakura et al.

    Transformation of carbon dioxide

    Chem. Rev.

    (2007)
  • Q. Liu et al.

    Using carbon dioxide as a building block in organic synthesis

    Nat. Commun.

    (2015)
  • Q.-W. Song et al.

    Efficient, selective and sustainable catalysis of carbon dioxide

    Green Chem.

    (2017)
  • C. Martín et al.

    Recent advances in the catalytic preparation of cyclic organic carbonates

    ACS Catal.

    (2015)
  • R.R. Shaikh et al.

    Catalytic strategies for the cycloaddition of pure, diluted, and waste CO2 to epoxides under ambient conditions

    ACS Catal.

    (2018)
  • M.A. Pacheco et al.

    Review of dimethyl carbonate (DMC) manufacture and its characteristics as a fuel additive

    Energy Fuels

    (1997)
  • M.O. Sonnati et al.

    Glycerol carbonate as a versatile building block for tomorrow: synthesis, reactivity, properties and applications

    Green Chem.

    (2013)
  • S.J. Poland et al.

    A quest for polycarbonates provided via sustainable epoxide/CO2 copolymerization processes

    Green Chem.

    (2017)
  • B. Schäffner et al.

    Organic carbonates as solvents in synthesis and catalysis

    Chem. Rev.

    (2010)
  • J. Vaitla et al.

    Enantioselective incorporation of CO2: status and potential

    ACS Catal.

    (2017)
  • W. Guo et al.

    Catalytic transformations of functionalized cyclic organic carbonates

    Angew. Chem. Int. Ed.

    (2018)
  • S. Foltran et al.

    Theoretical study on the chemical fixation of carbon dioxide with propylene oxide catalyzed by ammonium and guanidinium salts

    Catal. Sci. Technol.

    (2014)
  • C. Maeda et al.

    Recent progress in catalytic conversions of carbon dioxide

    Catal. Sci. Technol.

    (2014)
  • C.J. Whiteoak et al.

    Development in the context of ring expansion–addition of carbon dioxide to epoxides to give organic carbonates

    Synlett

    (2013)
  • M. Cokoja et al.

    Synthesis of cyclic carbonates from epoxides and carbon dioxide by using organocatalysts

    ChemSusChem

    (2015)
  • V. D’Elia et al.

    Cycloadditions to epoxides catalyzed by group III–V transition-metal complexes

    ChemCatChem

    (2015)
  • J. Meléndez et al.

    Synthesis of cyclic carbonates from atmospheric pressure carbon dioxide using exceptionally active aluminium(salen) complexes as catalysts

    Eur. J. Inorg. Chem.

    (2007)
  • W. Clegg et al.

    Cyclic carbonate synthesis catalysed by bimetallic aluminium–salen complexes

    Chem. Eur. J.

    (2010)
  • J.A. Castro‐Osma et al.

    Synthesis of cyclic carbonates catalysed by chromium and aluminium salphen complexes

    Chem. Eur. J.

    (2016)
  • X. Wu et al.

    A bimetallic aluminium(salphen) complex for the synthesis of cyclic carbonates from epoxides and carbon dioxide

    ChemSusChem

    (2017)
  • J. Melendez et al.

    One-component bimetallic aluminium(salen)-based catalysts for cyclic carbonate synthesis and their immobilization

    Dalton Trans.

    (2011)
  • Y. Xu et al.

    Aluminum complexes derived from a hexadentate salen-type Schiff base: synthesis, structure, and catalysis for cyclic carbonate synthesis

    Dalton Trans.

    (2017)
  • J. Steinbauer et al.

    Poly(ethylene glycol)s as ligands in calcium-catalyzed cyclic carbonate synthesis

    ChemSusChem

    (2017)
  • J. Steinbauer et al.

    An in situ formed Ca2+-crown ether complex and its use in CO2-fixation reactions with terminal and internal epoxides

    Green Chem.

    (2017)
  • L. Longwitz et al.

    Calcium-based catalytic system for the synthesis of bio-derived cyclic carbonates under mild conditions

    ACS Catal.

    (2018)
  • C.-Y. Li et al.

    Synthesis and characterization of trimetallic cobalt, zinc and nickel complexes containing amine-bis(benzotriazole phenolate) ligands: efficient catalysts for coupling of carbon dioxide with epoxides

    Dalton Trans.

    (2017)
  • C.J. Whiteoak et al.

    A powerful aluminum catalyst for the synthesis of highly functional organic carbonates

    J. Am. Chem. Soc.

    (2013)
  • Y. Qin et al.

    An aluminum porphyrin complex with high activity and selectivity for cyclic carbonate synthesis

    Green Chem.

    (2015)
  • Y. Yang et al.

    A highly stable MnII phosphonate as a highly efficient catalyst for CO2 fixation under ambient conditions

    Chem. Commun.

    (2018)
  • C. Xu et al.

    New lanthanide(III) coordination polymers: synthesis, structural features, and catalytic activity in CO2 fixation

    Dalton Trans.

    (2017)
  • J. Martinez et al.

    An efficient and versatile lanthanum heteroscorpionate catalyst for carbon dioxide fixation into cyclic carbonates

    ChemSusChem

    (2017)
  • T. Fujihara et al.

    Synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by MgCl2

    Chem. Lett.

    (2017)
  • H. Kisch et al.

    Bifunktionelle katalysatoren zur synthese cyclischer carbonate aus oxiranen und kohlendioxid

    Chem. Ber.

    (1986)
  • A. Decortes et al.

    Efficient carbonate synthesis under mild conditions through cycloaddition of carbon dioxide to oxiranes using a Zn(salphen) catalyst

    Chem. Commun.

    (2010)
  • A. Decortes et al.

    Ambient fixation of carbon dioxide using a ZnIIsalphen catalyst

    ChemCatChem

    (2011)
  • S. He et al.

    Topologically diverse shape-persistent bis-(Zn–salphen) catalysts: efficient cyclic carbonate formation under mild conditions

    Chem. Commun.

    (2016)
  • B. Bousquet et al.

    Zinc–azatrane complexes as efficient catalysts for the conversion of carbon dioxide into cyclic carbonates

    ChemCatChem

    (2018)
  • E. Mercade et al.

    Robust zinc complexes that contain pyrrolidine-based ligands as recyclable catalysts for the synthesis of cyclic carbonates from carbon dioxide and epoxides

    ChemCatChem

    (2016)
  • P. Patel et al.

    Efficient solvent free CO2 fixation reactions with epoxides under mild conditions by mixed ligand Zn(II) MOFs

    ChemCatChem

    (2018)
  • Cited by (66)

    View all citing articles on Scopus
    View full text