A laser trapping-spectroscopy study on the photocyanation of perylene across a single micrometre-sized oil droplets/water interface: droplet-size effects on photoreaction quantum yield

Kitagawa, Fumihiko; Kitamura, Noboru

doi:10.1039/b203259g

Cited by 11 publications

(7 citation statements)

References 24 publications

(26 reference statements)

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“…The fundamental influence of the enhanced electromagnetic energy density on the rate of photochemical reactions in micro- and nanodroplets has been recognized and calculations have provided limited evidence for enhanced photochemical rates 24 25 26 27 . Experimental results remain inconclusive concerning the influence of light enhancement on the kinetics, mainly because direct observation of the actual photoactive step was not possible 23 28 29 30 31 32 33 34 . The observation of size-dependent effects in ensembles of aerosol or emulsion droplets is often hindered because the droplet size distribution cannot be varied and determined with the necessary accuracy.…”

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confidence: 99%

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics

et al. 2016

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Photochemistry taking place in atmospheric aerosol droplets has a significant impact on the Earth's climate. Nanofocusing of electromagnetic radiation inside aerosols plays a crucial role in their absorption behaviour, since the radiation flux inside the droplet strongly affects the activation rate of photochemically active species. However, size-dependent nanofocusing effects in the photokinetics of small aerosols have escaped direct observation due to the inability to measure absorption signatures from single droplets. Here we show that photoacoustic measurements on optically trapped single nanodroplets provide a direct, broadly applicable method to measure absorption with attolitre sensitivity. We demonstrate for a model aerosol that the photolysis is accelerated by an order of magnitude in the sub-micron to micron size range, compared with larger droplets. The versatility of our technique promises broad applicability to absorption studies of aerosol particles, such as atmospheric aerosols where quantitative photokinetic data are critical for climate predictions.

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confidence: 99%

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics

et al. 2016

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“…In order to test this idea, we employed an interfacial cyanation reaction of an aromatic hydrocarbon (DH) in the present experiments. According to our previous studies on oilin-water emulsion systems, [14][15][16] we anticipated that the following photoreaction would proceed in a microchannel (see Scheme 1). Under laminar flow of an aqueous NaCN solution and an immiscible oil containing DH and an electron acceptor (A) in a microchannel, photoinduced electron transfer (PET) between DH and A takes place in the oil phase.…”

Section: Introductionmentioning

confidence: 99%

“…If the solubility of DCN in water is very poor, DCN will be distributed to the oil phase along solution flow in the microchannel (i.e., extraction). In the case of oil-in-water emulsion systems, cyanation reactions of pyrene (PyH), 14,15 perylene, 16 and so forth via a PET mechanism proceed across an oil-droplet/water interface. In practice, we demonstrated that the cyanation yield of DH increased with decreasing droplet size through the increase in the surface area/ volume ratio of a droplet.…”

Section: Introductionmentioning

confidence: 99%

Photocyanation of pyrene across an oil/water interface in a polymer microchannel chip

2002

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Photocyanation of pyrene (PyH) across an oil/water interface was explored by using two types of polymer microchannel chip. The chips (channel depth of 20 microm and width of 100 microm) were fabricated on the basis of photolithography and an imprinting method, with micromachined silicon templates being used for imprinting. As a typical example of the photoreaction, an aqueous NaCN solution and a propylene carbonate solution of PyH and 1,4-dicyanobenzene were brought separately into a Y-structured microchannel chip with the same flow velocity by pressure driven flow. Light irradiation onto the whole of the channel chip by a high-pressure Hg lamp resulted in formation of 1-cyanopyrene (PyCN), as confirmed by GC-MS analysis of the oil phase. The results demonstrated that the interfacial photochemical reaction of PyH proceeded successfully along the water/oil solution flow in the microchannel. Under optimum conditions by using a three-layer channel chip, absolute PyCN yields as high as 73% were attained with a reaction time of 210 s.

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“…36 Photoreaction analogous to that mentioned above proceeds in a water/oil interfacial system in the presence of CNand ArH/DCB in the water and oil phases, respectively. 3,6,37 In the case of microchip experiments, 25 an aqueous solution of NaCN (1 M) and a propylene carbonate (PC) solution of pyrene (PyH, 2.0 ¥ 10 -2 M) and DCB (4.0 ¥ 10 -2 M) are introduced to a Y-structured PSt microchannel chip at u = 0.2 mL/min as shown schematically in Fig. 10.…”

Section: ·4 Microreactorsmentioning

confidence: 99%

“…In practice, some chemical processes have been shown to be dependent on the size of a material: microdroplet or microparticle. [1][2][3][4][5][6][7] A large A/V ratio of a material is also very favorable for efficient heat management: fast heating/cooling cycles. Furthermore, it is clear that a minute volume is characterized by low amounts of chemicals/solvents, low energy, a short diffusion distance of each molecule, and so forth; 1 all these aspects are advantageous over those of a conventional bulk system.…”

Section: Introductionmentioning

confidence: 99%

Polymer Channel Chips as Versatile Tools in Microchemistry

2008

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The paper describes the fabrication and chemical applications of polymer microchannel chips, with special reference to in situ observations of the chemical/physical processes occurring in polystyrene microchannel chips, including those in microchannel-microelectrode/microheater chips. On the basis of absorption/fluorescence microspectroscopy and microelectrochemistry techniques, we show some characteristic features of liquid/liquid extraction, electrochemical responses, and photochemical/electrochemical/thermal synthetic reactions in microchannel chips.

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A laser trapping-spectroscopy study on the photocyanation of perylene across a single micrometre-sized oil droplets/water interface: droplet-size effects on photoreaction quantum yield

Cited by 11 publications

References 24 publications

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics

Photocyanation of pyrene across an oil/water interface in a polymer microchannel chip

Polymer Channel Chips as Versatile Tools in Microchemistry

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