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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 because of the low conversion achieved in the current design of the electrochemical process (0.7%), requiring high energy consumption in the separation process. The results suggest that the process yield must be increased to at least 20% to reduce the GWP to a level comparable with the commercial process. At this yield, the electrochemical process also becomes more sustainable than the commercial system for most other impacts considered. The study demonstrates how LCA can play a key role in the development of environmentally more sustainable processes during design by combining experimental data and process simulation at an early stage of technology development.

In this study, two new alternative preys: Grapsus adscensionis zoeae (as sole prey) and Palaemon elegans zoeae (in cofeeding with Artemia sp.), as well as, Artemia sp. juveniles were used as feed for octopus paralarvae, as a way to understand its lipid requirements. Total lipid (TL) content, lipid class (LC) and fatty acid (FA) profiles of preys, octopus hatchlings and 9-day-old paralarvae were analysed. Growth and survival of the paralarvae were also determined. Regardless the prey provided, a notable shift in the lipid profile of paralarvae was registered after 9 days of rearing. The highest index of growth rate (IGR) recorded when decapod crustacean zoeae were supplied might have some relation with levels of 20:4n-6 (ARA) and DHA/EPA ratio observed. In this sense, Grapsus adscensionis zoeae leaded to a higher content of ARA and a lower content of EPA, which may indicate a possible competition between these two FA. For that a balanced EPA/ARA ratio might be significant in this species nutrition without disconsidering DHA levels as an essential fatty acid. Finally, the changes observed in paralarvae FA profile might not only be related to prey FA profile, but also with changes occurring in the lipid classes contents.

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applications, and has been suggested as a potential gasoline additive. However, DMC has traditionally been produced from hazardous phosgene and CO routes, which encourages the interest in developing new processes. The aim of this work is to study the valorization process for the direct electrosynthesis of DMC from CO 2 and methanol using CH 3 OK and the ionic liquid 1-butyl-3-methylimidazolium bromide, avoiding the addition of carcinogenic compounds.This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/jctb.4445 This article is protected by copyright. All rights reserved Accepted Article Accepted Article RESULTS: The evolution of the concentration of DMC was studied in a filter-press electrochemical cell with anodic and cathodic compartments separated by a Nafion 117 membrane, operating for 48 h. A final DMC concentration of 15.07 mmol·L -1 was observed.Moreover, analysis of the by-products obtained in the process revealed the formation of tetramethyl orthocarbonate and dimethoxymethane, which were detected and quantified in the liquid phase. A simplified reaction scheme was also proposed according to the results obtained.CONCLUSION: Unlike all previous works that used an undivided cell, the new experimental results of this study using a divided cell can serve as a reference for further research to overcome current limitations.

BACKGROUND: The valorization of CO 2 into added-value products appears as a promising

Life Cycle Assessment (LCA) has been used to assess the environmental sustainability of the chlor-alkali production in Europe. The three current technologies applied nowadays are mercury, diaphragm, and membrane cell technology. Despite, having achieved higher energy efficiencies since the introduction of membrane technology, energy consumption is still one of the most important issues in this sector. An emerging technology namely oxygen-depolarised cathodes (ODC) is suggested as a promising approach for reducing the electrolysis energy demand. However, its requirement of pure oxygen and the lack of production of hydrogen, which could otherwise be valorised, are controversial features for greener chlorine production. The aim of this work is to evaluate and compare the environmental profiles of the current and emerging technologies for chlorine production and to identify the main hot spots of the process. Salt mining, brine preparation, electrolysis technology and products treatment are included inside the system boundaries. Twelve environmental impact categories grouped into natural resources usage and environmental burdens are assessed from cradle to gate and further normalised and weighted. Furthermore, hydrogen valorisation, current density and allocation procedure are subjected to sensitivity analysis. Results show that the electrolysis stage is the main contributor to the environmental impacts due to energy consumption, causing 99.5-72% of these impacts. Mercury is the less environmentally sustainable technology, closely followed by diaphragm. This difference becomes bigger after normalisation, owing to hazardous waste generated by mercury technique. Conversely, best results are obtained for ODC instead of membrane scenario, although the reduction in energy requirements is lesser than expected (7%).