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The “Photo-Friedel−Crafts Acylation” of 1,4-Naphthoquinones

“…15 suns, 24 m 2 reflecting mirror area), 3 (500 g) in a tertbutyl alcohol/acetone mixture (80 l) was converted into the acylation product (6b) within 3 d (Germany, August 1996), and in 90% yield without appreciable amounts of by-products. [33] This result clearly demonstrated that the goal of green photochemistry with sunlight was achievable, although further modifications were desirable.…”

Wolff–Kishner reduction reactions using a solar irradiation heat source and a green solvent system

“…Like the CPC collector, this design is also non-mobile, and is at a fixed slope of 30°to the position of the sun. Due to the design of this collector, two major disadvantages were observed: reacting components were not properly mixed and the solution solidified overnight during the cold weather months (10).…”

“…The CPC reactor is run with a fixed slope of 50°to the position of the sun, and reaction mixtures are passed through the absorber tubes during the experiment. For overnight reactions, the reactor is covered with a plastic foil to help maintain heat to the system (10).…”

Photoinduced acyl transfer

“…[54] The most spectacular use of the photoinduced acylation was demonstrated by Mattay et al on a large scale using solar light (Scheme 34). [55][56][57][58][59][60] Irradiation of a solution of 1,4-naphthoquinone in tert-butanol/acetone (500 g) with butyraldehyde in a 24 m 2 mirror system for 3 days (Germany, August 1996) gave the acylated product in 90% yields without major side products. During the reaction, 300 moles of photons (between 300 and 500 nm, in the major absorption range of 1,4-quinones) were collected.…”