The Quantum Yield of Monochloroacetic Acid Hydrolysis

SMITH, R. N. M.; Leighton, Philip A.; Leighton, Wesley G.

doi:10.1021/ja01878a009

Cited by 53 publications

(19 citation statements)

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“…36 On the other hand, the rate of MCAA photohydrolysis is also determined and quantified by the quantum yield, defined as = (yield of photoproducts)/(number of photons absorbed). The variation in the quantum yield of MCAA photohydrolysis with temperature 40 is shown in Fig. 5 (open circles), and proportionally increases from MCAA (25 • C) = 0.31 to MCAA (69 • C) = 0.69 with temperature coefficient +0.009/ • C. 30 The temperature effect on the quantum yield is opposite to that on the EDL light intensity of the 254 nm line: therefore the optimal temperature for the photochemical reaction course is about 50…”

Section: Resultsmentioning

confidence: 99%

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Cı́rkva

Relich

Hájek

2009

J of Chemical Tech & Biotech

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BACKGROUND: Low-pressure batch and continuous-flow microwave photoreactors were equipped with microwave powered quartz mercury electrodeless discharge lamps (Hg-EDLs). Photohydrolysis of aqueous mono-chloroacetic acid (MCAA) into hydroxyacetic acid and HCl was chosen as the model reaction to evaluate these photoreactors. The effects of operational parameters on the MCAA photolysis through a UV/MW process were investigated.

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Section: Resultsmentioning

confidence: 99%

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Cı́rkva

Relich

Hájek

2009

J of Chemical Tech & Biotech

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“…23 This result supports that the reaction (13) and (14) could be happen on the surface of TiO 2 particles in the irradiation of aqueous ammonia solution. The reaction probability for the reactions (13) and (14) increases in higher concentration of aqueous ammonia solution and more NH 2 radicals thereby produced. This is a reason why hydrazine gives the higher yield with increasing the concentration of ammonia.…”

Section: Resultsmentioning

confidence: 99%

“…The intensity of the 253.7 nm light was determined by monochloroacetic acid actinometer. 13,14 The yield of chloride ion (Cl − ) formed during the irradiation of aqueous monochloroacetic acid was measured by spectrophotometric method. The lamp intensity was found to be 5.37 × 10 18 quanta.…”

Section: Methodsmentioning

confidence: 99%

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Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂

2008

Bulletin of the Korean Chemical Society

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Ammonia is produced in huge quantities worldwide not only by commercial chemical factories but by decaying vegetation, garbage, even decomposition of the other protein materials. Ammonia with foul odor causes a serious environmental pollution in the atmosphere. Therefore, the decomposition of ammonia has attracted considerable attention in respect to environmental pollution of the atmosphere.Earlier investigation on the decomposition of ammonia using a light was performed by means of radiolysis 1,2 and photolysis 3-8 in the gaseous state. Ammonia molecules are incorporated into water droplets and form liquid aerosols which can range in diameter with nanoscale particle.9 Recently, we have reported on the photochemical decomposition of aqueous ammonia in the absence and presence of oxygen using 184.9 nm UV light. 10 It was found that hydrazine was mainly produced by the dimerization of NH 2 radicals and oxygen affected the formation of hydrazine. In order for a photochemical reaction to occur, reactant chemical species must absorb the light illuminated. NH 3(aq) , NH 4 + (aq) , OH aq and H 2 O species exist in the aqueous ammonia solution. Since such chemical species have relatively strong intramolecular chemical force, a high enough energy is necessary to begin the photochemical reaction. It corresponds to vacuum UV light to break the chemical bond of such chemical species. The photochemical reaction of aqueous ammonia can not be carried out by a natural ultraviolet solar radiation on the earth's surface, because the solar energy reached on the earth's surface is the wavelength above λ = 314 nm UV light. It is necessary to use a photocatalyst to begin the photochemical decomposition of aqueous ammonia. Metal oxide such as titanium oxide and zinc oxide may be used for the purpose as a photocatalyst. It is well known that titanium oxide absorbs photons with energy higher than its bandgap (~3.2 eV) and electronhole pairs, so called geminated form, are produced.11 To our knowledge, there has been no report to date on the quantitative results for photochemical reaction of aqueous ammonia in the presence of TiO 2 particles. Since the photochemical reactions are very fast, products analysis is generally used to determine the photochemical behavior in a system. The aim of this study is to present the quantitative results for the photochemical reaction of the aqueous ammonia containing TiO 2 particles using 253.7 nm UV light, and to elucidate the behavior of TiO 2 during the photochemical reaction of aqueous ammonia based on the product analysis. Experimental SectionLightsource and Actinometry. Irradiations were carried out at 25 o C usinglow pressure Hg lamp (Osram HNS 10W/ U OFR). Low pressure Hg lamp is classified into two types depending on the method of its emitting wavelength; ozone generating lamp and ozonefree lamp. 12 The ozonefree lamp used in this study emits only 253.7 nm UV light, but on the other hand ozone generating lamp emits two monochromatic lights of 184.9 and 253.7 nm. The lamp was mounted in a quart...

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“…The solutions were purged with high purity argon in order to remove the oxygen before irradi ation. Actinometry with airfree 0.5 mol dm-3 chloroacetic acid (Qa -=0.34 at 30 °C) [23,24] yielded a light intensity of I0 = 5 x 1017 quanta ml-1 min-1.…”

Section: Uv-irradiationmentioning

confidence: 99%

Steady-State and Flash Photolysis Investigations of 1 H-Indene-l,3(2H)-Dione Derivatives

Grabner

Quint

Getoff

et al. 1991

Zeitschrift Für Naturforschung A

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Pyrophthalone (PP, 2-(2-pyridinyl)-l H-indene-l,3(2H)-dione) and quinophthalone (QP, 2-(2-quinolinyl)-l H-indene-l,3(2 H)-dione) were investigated in various solvents with respect to their photostability. It was found that PP and QP in ethanol as well as QP in cyclohexane are rather stable under steady-state conditions using UV light (A = 253.7 nm). Conventional as well as laser flash photolysis of airfree aqueous alkaline solutions (pH 12) lead to the formation of different radicals and solvated electrons (eã). Some reaction rates were determined and probable reaction mechanisms were postu lated.

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The Quantum Yield of Monochloroacetic Acid Hydrolysis

Cited by 53 publications

References 0 publications

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂

Steady-State and Flash Photolysis Investigations of 1 H-Indene-l,3(2H)-Dione Derivatives

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The Quantum Yield of Monochloroacetic Acid Hydrolysis

Cited by 53 publications

References 0 publications

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

Photochemical Behavior of Ammonia in Aqueous Suspension of TiO2

Steady-State and Flash Photolysis Investigations of 1 H-Indene-l,3(2H)-Dione Derivatives

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Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂