1 3
Topics in Current Chemistry (2018) 376:45
mitigate or overcome those well-known limitations, like the reaction control module
described above. These recent developments have reduced the distance for the adoption of solar photochemistry in the production of chemicals. Another potential application of solar photochemistry could be the photocatalytic lignin-depolymerization,
creating a renewable approach to bio-based chemicals [48].
In the absence of subsidies directly promoting solar photochemistry, it is likely
that the first industrial applications will be specialty chemicals having niche markets and high profit margins. With further development in the reactor efficiencies,
it is expected that in the future the solar manufacturing of fine chemicals could be
economically competitive for several fine and specialty chemicals. Nowadays, specialty chemicals are usually produced batchwise as opposed to the continuous process that characterizes most bulk chemicals. Since efficient solar photochemistry
is inextricably linked with a flow operation mode, the barrier for adoption is currently significant as both a batch-to-flow and a lamp-to-solar conversion are needed.
The reluctance to change of the chemical industry is well exemplified by economic
evaluation of the industrial synthesis of ε-caprolactam via solar photooximation of
cyclohexane, which already in 1999 had shown that the return of investment for the
solar photochemical process is superior to the existing lamp-driven approach [49,
50]. Nevertheless, no solar-powered power plants that we are aware of have been
commissioned or even planned so far. We hope that future research in simpler, more
efficient and versatile reactor design, coupled with the growing interest toward visible-light photochemistry, can change this situation in the future and unleash the sustainable potential of solar energy for the production of chemicals.
Acknowledgements DC and TN would like to acknowledge the European Union for a Marie Curie ITN
Grant (Photo4Future, Grant No. 641861).
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution,
and reproduction in any medium, provided you give appropriate credit to the original author(s) and the
source, provide a link to the Creative Commons license, and indicate if changes were made.
References
1. Esen V, Sağlam Ş, Oral B (2017) Light sources of solar simulators for photovoltaic devices: a
review. Renew Sustain Energy Rev 77:1240–1250
2. Protti S, Fagnoni M (2009) The sunny side of chemistry: green synthesis by solar light. Photochem
Photobiol Sci 8(11):1499–1516
3. Roth HD (1989) The beginnings of organic photochemistry. Angew Chem Int Ed 28(9):1193–1207
4. Albini A, Fagnoni M (2004) Green chemistry and photochemistry were born at the same time.
Green Chem 6(1):1–6
5. Roth HD (2001) Twentieth century developments in photochemistry. Brief historical sketches. Pure
Appl Chem 73(3):395–403
6. Schönberg A, Schenck GO, Neumüller OA (1968) Preparative organic photochemistry. SpringerVerlag, Berlin
7. Zhang Y, Sivakumar M, Yang S, Enever K, Ramezanianpour M (2018) Application of solar energy
in water treatment processes: a review. Desalination 428:116–145
25
Reprinted from the journal
Topics in Current Chemistry (2018) 376:45
mitigate or overcome those well-known limitations, like the reaction control module
described above. These recent developments have reduced the distance for the adoption of solar photochemistry in the production of chemicals. Another potential application of solar photochemistry could be the photocatalytic lignin-depolymerization,
creating a renewable approach to bio-based chemicals [48].
In the absence of subsidies directly promoting solar photochemistry, it is likely
that the first industrial applications will be specialty chemicals having niche markets and high profit margins. With further development in the reactor efficiencies,
it is expected that in the future the solar manufacturing of fine chemicals could be
economically competitive for several fine and specialty chemicals. Nowadays, specialty chemicals are usually produced batchwise as opposed to the continuous process that characterizes most bulk chemicals. Since efficient solar photochemistry
is inextricably linked with a flow operation mode, the barrier for adoption is currently significant as both a batch-to-flow and a lamp-to-solar conversion are needed.
The reluctance to change of the chemical industry is well exemplified by economic
evaluation of the industrial synthesis of ε-caprolactam via solar photooximation of
cyclohexane, which already in 1999 had shown that the return of investment for the
solar photochemical process is superior to the existing lamp-driven approach [49,
50]. Nevertheless, no solar-powered power plants that we are aware of have been
commissioned or even planned so far. We hope that future research in simpler, more
efficient and versatile reactor design, coupled with the growing interest toward visible-light photochemistry, can change this situation in the future and unleash the sustainable potential of solar energy for the production of chemicals.
Acknowledgements DC and TN would like to acknowledge the European Union for a Marie Curie ITN
Grant (Photo4Future, Grant No. 641861).
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution,
and reproduction in any medium, provided you give appropriate credit to the original author(s) and the
source, provide a link to the Creative Commons license, and indicate if changes were made.
References
1. Esen V, Sağlam Ş, Oral B (2017) Light sources of solar simulators for photovoltaic devices: a
review. Renew Sustain Energy Rev 77:1240–1250
2. Protti S, Fagnoni M (2009) The sunny side of chemistry: green synthesis by solar light. Photochem
Photobiol Sci 8(11):1499–1516
3. Roth HD (1989) The beginnings of organic photochemistry. Angew Chem Int Ed 28(9):1193–1207
4. Albini A, Fagnoni M (2004) Green chemistry and photochemistry were born at the same time.
Green Chem 6(1):1–6
5. Roth HD (2001) Twentieth century developments in photochemistry. Brief historical sketches. Pure
Appl Chem 73(3):395–403
6. Schönberg A, Schenck GO, Neumüller OA (1968) Preparative organic photochemistry. SpringerVerlag, Berlin
7. Zhang Y, Sivakumar M, Yang S, Enever K, Ramezanianpour M (2018) Application of solar energy
in water treatment processes: a review. Desalination 428:116–145
25
Reprinted from the journal