Emeline Vedrenne

Development of eco-friendly porous fired clay bricks using pore-forming agents: a review.

Today, clay bricks are facing technological challenges and are uncompetitive compared to materials such as concrete. Their performance must be improved if they are to stand up to the competition. Increasing environmental concerns over the accumulation of unmanaged wastes from agricultural or industrial productions have made these good candidates for incorporation into building materials to improve their performance. This process leads to the formation of pores in the bricks, producing lightweight and sustainable building materials. This paper reviews the different pore-forming agents from renewable or mineral resources as described in the literature. It also presents the impact of pore-forming agents on the physical, mechanical and thermal properties of clay bricks.

Synthesis of new cellulose ethers using Suzuki-Miyaura reactions.

Cellulose ethers are functionalized biopolymers that are industrially produced through drastic conditions employing gaseous reactants with a high risk of industrial accident. The cellulose ethers that are commercially available generally bear short carbon-chains. In this work, an alternative method using non-gaseous chemicals is proposed. It relies on the use of the Suzuki-Miyaura reaction employing mild, moisture- and air-stable conditions. Relatively innocuous reagents are used for this step, which allows the formation of a wide range of cellulose ethers bearing various functional groups with different chain-length.

LCA case study: comparison between independent and coproduction pathways for the production of ethyl and n-butyl acetates

PurposeThe production of ethyl acetate and n-butyl acetate was investigated through two different pathways: either by independent reactions or by coproduction. In the coproduction pathway, the n-butyl acetate was produced by reusing the by-products of the synthesis of ethyl acetate. This study provides a comparison of the environmental impacts of these two pathways using a life cycle assessment (LCA). A discussion about the use of LCA on chemicals and its challenges was also developed.MethodsEthyl acetate and n-butyl acetate were synthesized with maximum respect to the principles of green chemistry (use of heterogeneous catalyst, energy savings, minimum steps). An innovative pathway was developed to avoid waste production, by reusing all the by-products of syntheses. After characterizing the feasibility of using these solvents in paint formulations, their potential impacts on the environment were evaluated through a cradle to gate analysis, up to the synthesis at laboratory scale. Most of the foreground data were directly collected with experimental trials. The background data that were not available in the Ecoinvent 3.1 database were estimated thanks to literature or proxys. Evaluations were then performed on the SimaPro 8.1.1 LCA software, using a derivative of ILCD 2011 1.05 as life cycle impact assessment methodology.Results and discussionThe coproduction of both acetates led to the synthesis of purified ethyl acetate (purity of 92.1% w/w) and n-butyl acetate (purity of 97.1% w/w), after distillation. These results were quite similar to those obtained when independent syntheses were carried out. On an environmental point of view, it was found that the reagents preparation was always the step of the process responsible of the majority of the environmental impacts. The comparison between independent syntheses and coproduction showed that recycling the acetic acid produced during the first esterification (ethyl acetate from ethanol and acetic anhydride) led to a decrease of the impacts from 5 to 23% for all the impact categories.ConclusionsThis innovative coproduction of ethyl and n-butyl acetates led to interesting results from both a technical and environmental perspective, with a clear reduction of the environmental impacts. In a context of sustainable chemistry, this appears to be a very interesting way of production. Concerning the LCA of chemicals, a lot of work is still needed in order to improve the accuracy and the reliability of the assessment.