Environmental Assessment of Dimethyl Carbonate Production: Comparison of a Novel Electrosynthesis Route Utilizing CO2with a Commercial Oxidative Carbonylation Process

Isabel Garcia-Herrero,Manuel Alvarez-Guerra,Rosa Marisa Cuéllar-Franca,Víctor Manuel Enríquez-Gutiérrez,Angel Irabien,Adisa Azapagic

doi:10.1021/acssuschemeng.5b01515

Isabel Garcia-Herrero, Manuel Alvarez-Guerra + Show 4 more

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https://doi.org/10.1021/acssuschemeng.5b01515

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Abstract

Life cycle assessment (LCA) has been used at an early design stage to evaluate the environmental sustainability of a novel process for synthesizing dimethyl carbonate (DMC) from waste CO2. The process involves an electrochemical reaction of CO2 and methanol in the presence of potassium methoxide and the ionic liquid 1-butyl-3-methylimidazolium bromide to produce DMC. Experimental data and process simulation have been combined to estimate the environmental impacts and compare them to the conventional commercial “Eni” process based on oxidative carbonylation of methanol. Eleven environmental impact categories have been assessed from “cradle to gate”, including global warming potential (GWP), toxicity potentials, and resource depletion. For example, GWP of DMC produced in the electrochemical process ranges from 63.3 to 94.5 kg CO2 eq./kg DMC, depending on a process configuration. This is around 25 times higher than GWP of the commercial process estimated in this study at 3.2 kg CO2 eq./kg DMC. This is becaus...

Highlights

Dimethyl carbonate (DMC) is an alkyl carbonate [(CH3O)2CO] which can be used in different applications
We focus on an electrochemical route developed recently,[18,19] using electrosynthesis of dimethyl carbonate (DMC) from waste CO2 and methanol in the presence of potassium methoxide (CH3OK) and the ionic liquid 1-butyl3-methylimidazolium bromide
The Life cycle assessment (LCA) study has been carried in accordance with the ISO 14040/44 methodology[24,25] and follows some of the recommendations made in previous LCA studies.[26−29] GaBi V4.430 has been used for the LCA modeling and the CML 2001 impact assessment method[31] to estimate the following 11 environmental impacts: global warming potential (GWP), abiotic depletion potential of elements (ADPelements), abiotic depletion potential of fossil resources (ADPfossil), acidification potential (AP), eutrophication potential (EP), human toxicity potential (HTP), terrestrial ecotoxicity potential (TETP), freshwater aquatic ecotoxicity potential (FAETP), marine aquatic ecotoxicity potential (MAETP), ozone layer depletion potential (ODP), and photochemical oxidants creation potential (POCP)

Summary

Introduction

Dimethyl carbonate (DMC) is an alkyl carbonate [(CH3O)2CO] which can be used in different applications. III) is based on the carbonylation of methanol but uses NOx instead of O2;6 it contributes 11% to the DMC market.[8] In addition, new alternative processes for DMC are being studied, including transesterification of ethylene carbonate (route IV) which was setup at a commercial scale in the early 2000s by Asahi (as described in ref 9) transesterification of urea (route V10) and direct synthesis from CO2 (route VI11) The latter is arguably the most attractive option, as it allows the use of waste CO2 captured from power plants or other industrial sources as a feedstock for the production of chemicals such as DMC. Electrochemical techniques could represent a Received: November 17, 2015 Revised: February 26, 2016 Published: March 7, 2016

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