A Mechanistic Study of Photocyanation of Pyrene in Oil-in-Water Emulsion Systems

Abstract

A highly efficient one-step photocyanation reaction of pyrene was shown to proceed in oil-in-water emulsion systems. As a typical example, photoirradiation of pyrene in the presence of 1,4-dicyanobenzene and NaCN in a benzonitrile/water mixture (1/100, vol %) under vigorous stirring gave 1-cyanopyrene in a conversion yield of 83%, while an analogous reaction in an acetonitrile/water mixture (9/1, vol %) yielded this product in 61% yield. We evaluated the quantum yield of photocyanation in the oil-in-water emulsion system to be 0.17. Under optimum conditions, the quantum yield was improved to 0.68. Characteristics and possible mechanisms of the photocyanation reaction are discussed in detail.

Laser ionization/time-of-flight mass spectrometry for the direct analysis of emulsions

“…To date, several techniques have been used to evaluate emulsions: spectrometry, light scattering, and small X-ray scattering. [23][24][25][26][27][28][29] To the best of our knowledge, an online mass spectrometric and stability evaluation approach of emulsions has not yet been accomplished. Normally, appropriate pretreatments such as drying or matrix addition are performed before the mass analysis.…”

Electrochemical Reactions in Microreactors

“…For example, a polymer microchip having a microchannel (100 mm width and 20 mm depth) integrated with electrodes [8,9] has been developed by Kitamura and coworkers. The anodic oxidation of pyrene in the presence of NaCN was carried out in the reactor with a serial electrode configuration (Figure 9.1) [10][11][12]. In this system, the electric current flow and the liquid flow are parallel.…”

Aryl Cation Chemistry as an Emerging Versatile Tool for Metal-Free Arylations

“…76 In a recent example, the photocyanation of pyrene to give 1-cyanopyrene (83% yield) was accomplished by irradiation in the presence of 1,4-dicyanobenzene (an electron-transfer sensitizer) and NaCN in an oil-in-water emulsion system. 77 Cyanation of electron-rich aromatics is still a challenge, however. Once again, the irradiation, this time in a wateracetonitrile 1:3 (or 1:1) solution of KCN, of electron-donating substituted phenyl halides or esters overcomes this limitation.…”