Table 4 The relation of the phase-out of substances of concern with the 12 principles of green chemistry as defined by the ACS
Principle | Relevance for substances of concern phase-out |
|---|---|
Prevention | No direct impact |
Atom economy | Substitution can have an impact on the atom economy, as alternatives could result in longer and less efficient routes |
Less hazardous chemical syntheses | As outlined in the introduction, categorisation of substances as SVHCs occurs due to their hazard properties (e.g. carcinogenicity, mutagenicity). Therefore, phasing out substances of concern is directly correlated with using less hazardous reagents. Some examples are chromium-mediated oxidations, which have been completely removed from modern pharmaceutical chemistry |
Designing safer chemicals | No direct impact (design of safer drug substances in terms of their environmental degradability and toxicological profile is an important topic in modern medicinal chemistry but is only linked by way of structural motifs which need to be incorporated during their synthesis into substances of concern) |
Safer solvents and auxiliaries | This in principle is directly related to the phase-out of substances of concern and at the same time a tremendous technical challenge, because key aprotic polar solvents have been identified by ECHA as SVHCs: DMAC, DMF, NMP, 2-methoxyethyl ether (DIGLYME) Toxicological safety is only one aspect. Alternatives to the solvents mentioned are often less stable and result in more dangerous (in the sense of physical safety) processes |
Design for energy efficiency | No direct impact |
Use of renewable feedstocks | No direct impact |
Reduce derivatives | No direct impact |
Catalysis | No direct impact |
Design for degradation | Particularly in the area of surfactants, it may be possible to find good substitutes, as shown by the replacement of alkylphenol ethoxylates We are also aware that there is a broad choice of readily degradable chelators A special case is the replacement of inorganic process aids by readily biodegradable organic substances (ideally without heteroatoms). An example is the replacement of boric acid and borates as buffer substances |
Real-time analysis for pollution prevention | No direct impact |
Inherently safer chemistry for accident prevention | Process safety is of utmost importance in research, development and manufacturing. When introducing a less hazardous (in terms of toxicology or ecotoxicology) substance, the process safety might deteriorate |