Safety considerations of furanic compounds from an industrial safety point of view - an integrated biorefinery approach
Résumé
The European Union?s approach of replacing progressively fossil sources by other renewable sources to support the transportation fuel and production of commodity polymers is one significant driver of the bio-economy. Today?s research is focusing more on faster and effective sustainable biomass conversion techniques with successful attempts resulting in producing new versatile carbon-based building blocks from lignocellulosic biomass residues. Chemicals such as 5-hydroxymethylfurfural (HMF) and furfural can be produced by the dehydration of cellulosic and hemicellulosic fractions to extract C5 and C6 sugars which can be further converted into various furanic derivatives (FD) such as 2,5-furandicarboxylic acid (FDCA) or furfuryl alcohol (FA), which are well-known precursors of bio-based polymers [1]?[3]. Owing to the wide variety of phys-chem properties, and wide diversity of existing and potential FD structures (fig.1), one can anticipate risk profiles may be triggered and can highly vary during their synthesis and targeted applications. First order about hazards pertaining to marketed chemicals can be obtained from various haz-mat classification systems as those derived internationally from the (GHS) (like CLP regulation in the EU) and from the UN TDG Model Regulations for the transport of dangerous goods [4], [5]. However, except for a few well known FD (such as furan, furfural, furfuryl alcohol, hydroxymethylfurfural etc), these regulations have limited interest as in most cases, no harmonized classification or UN number have been given to FD. Moreover, access to Material Safety Data Sheets (MSDS) where hazard rating must be done as a duty of the supplier are only available when the FD of interest has already been put on the market. Besides, use of conventions in those haz-mat classifications leads very often to misleading messages when the threshold value for a given hazard is not reached. For instance, qualifying a compound as ?non-flammable? is misleading to some extent. Similar to most ionic liquids, many FD (furfural FP 60 0C) does not enter the class of flammable liquids, due to their flash point (FP) position compared to limits defined by regulatory frameworks (eg. flammable substances have a flash point ?60 °C in the CLP) [6]. Depending on the context of use, compounds that are not identified as ?dangerous? may still induce flammable, corrosive, oxidative, toxic and eco-toxic issues [7], meaning that these classifications are set by pure convention (fig.2). In addition, thermal stability, speed of combustion, type of surrounding environment, conventional methods of storage and disposal, safety training to the employees, etc., are some of the governing factors that have to be considered in further evaluation of risk at use beyond haz-mat classification. Growing research, innovation in the field of biomass conversion processes is leading to synthesis of brand new FD which raise the need of providing holistic safety assessment. To meet the new market requirements and to resolve some of the above mentioned discrepancies, there is a need for careful examination of the potential risks associated in the family of FD. The current study is part of the HUGS project [8] and focuses on examining the safety profile of existing and some newly synthesized FD, while safety aspects of humins & and other derivatives like levulenic acid will also be taken into account. Specific focus is given on learning their thermal stability, flammability, or combustion behavior during fire scenarios, via fire propagation apparatus & flash point tests. The study aims at identifying and defining specific trends of physico-chemical properties of the family of FD thus developing knowledge to choose the best-suitable compound based on its functionality and applications while integrating economics and sustainability.