Chemistry Reference
In-Depth Information
9
Outlook
Where will the chemistry of phosgenation reactions go?
Contradictions about phosgene chemistry will endure, albeit in another sense
and manner as outlined in Chapter 1. As we see it, there will probably be four,
partially contradictory, pathways.
Methods and processes for the supply of phosgene on demand of the consumers
will be developed further. In this way, the present gap of providing consumers with
1-100 kg amounts of phosgene per day will be closed. This will be the field of
safety phosgenation (see Sections 2.2.2.1 and 7.1.2).
The development of phosgene equivalents and substitutes is still not at an end.
Phosgene equivalents with lower vapor pressures and higher TLVs remain a desir-
able aim, and a furtherance in the use of triphosgene for the same applications as
phosgene is likely.
Specifically designed sustainable phosgene substitutes for specific applications
will be increasingly used (like the already used BOP, BDDC, CDC, and Burgess
reagent; see Chapter 4) to perform selective reactions that comply with the intrin-
sic (yield, reactivity, handling, work-up) and extrinsic (safety, toxicity, environmental
impact) criteria set out in Chapter 6.
Fulfilment of the requirements of ''green chemistry'', such as atom-e
ciency, the
avoidance of waste, toxic and dangerous chemicals, better performing compounds,
their biodegradability, eco-compatible solvents (H
2
O, supercritical CO
2
), energy re-
duction, and renewable materials, will be the fourth path for the future of phos-
gene chemistry.
Phosgene chemistry may then be renamed, or it might keep its traditional name
in remembrance of a very small molecule of four atoms, with all its enormous
synthetic potential and economic importance that has endured since the very be-
ginnings of organic and industrial chemistry.
Only the future will tell what pathway(s) will be followed up.