scholarly journals Laser-Induced Photochemical Reaction of Maleic Acid Solutions in the Presence of Hydrogen Peroxide

1997 ◽  
Vol 17 (2) ◽  
pp. 97-108 ◽  
Author(s):  
Yuichi Shimizu ◽  
Shun'ichi Sugimoto ◽  
Shunichi Kawanishi ◽  
Nobutake Suzuki
Keyword(s):  
Hydrogen Peroxide ◽  
Maleic Acid ◽  
Photochemical Reaction ◽  
Room Temperature ◽  
Direct Synthesis ◽  
Reaction Scheme ◽  
Photochemical Reactions ◽  
The Other ◽  
Acid Solutions ◽  
Selective Formation

Targeting the selective and direct synthesis of tartaric acid (TA), the photochemical reactions of maleic acid (MA) solutions containing H2O2. in various solvents have been investigated using four wavelengths in the UV region between 193 and 351 nm, with high intensity from an excimer laser. All the laser irradiations in H2O resulted in the direct synthesis of TA with lower selectivity and it was found that, with XeF-laser (351 nm) irradiation in 1,4-dioxane, TA is selectively and directly synthesized from MA containing H2O2 of lower concentration at room temperature. On the other hand, none of the irradiations in methanol, N,N-dimethylformamide, acetonitrile, and tetrahydrofuran gave the selective formation of TA. On the basis of these results, the reaction scheme for the selective formation of TA is discussed.

scholarly journals Sunscreen-Assisted Selective Photochemical Transformations

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2125
Author(s):  
Or Eivgi ◽  
N. Gabriel Lemcoff
Keyword(s):  
Photochemical Reaction ◽  
Reaction Pathway ◽  
General Procedure ◽  
Molar Absorptivity ◽  
Photochemical Reactions ◽  
The Other ◽  
Protecting Group ◽  
Selective Reaction ◽  
Photochemical Transformations ◽  
Photolabile Protecting Group

In this review, we describe a simple and general procedure to accomplish selective photochemical reaction sequences for two chromophores that are responsive to similar light frequencies. The essence of the method is based on the exploitation of differences in the molar absorptivity at certain wavelengths of the photosensitive groups, which is enhanced by utilizing light-absorbing auxiliary filter molecules, or “sunscreens”. Thus, the filter molecule hinders the reaction pathway of the least absorbing molecule or group, allowing for the selective reaction of the other. The method was applied to various photochemical reactions, from photolabile protecting group removal to catalytic photoinduced olefin metathesis in different wavelengths and using different sunscreen molecules. Additionally, the sunscreens were shown to be effective also when applied externally to the reaction mixture, avoiding any potential chemical interactions between sunscreen and substrates and circumventing the need to remove the light-filtering molecules from the reaction mixture, adding to the simplicity and generality of the method.

scholarly journals Pengaruh Perendaman Telur dengan Larutan Hidrogen Peroksida terhadap Penurunan Bobot, Haugh Unit dan Indeks Putih Telur Itik Konsumsi Selama Penyimpanan pada Suhu Ruang

2017 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Nilawati Widjaya
Keyword(s):  
Hydrogen Peroxide ◽  
Weight Reduction ◽  
Room Temperature ◽  
The Other ◽  
Duncan Multiple Range Test ◽  
Egg Weight ◽  
Chamber Temperature ◽  
Weight Decrease ◽  
Range Test ◽  
Haugh Unit

<p>This objective of the research was to know the effect of soaking with hydrogen<br />peroxide on weight reduction, haugh unit and albumen index of duck eggs during storage at room temperature. The research was designed as Completely Randomize Design (CRD) wtih four treatments and six replicates each. The treatments were: soaking with aquades, soaking with 1, 2, and 3% of hydrogen The data were analyzed by analysis of variance and continued with Duncan Multiple Range Test. The results indicated that soaking with hydrogen peroxyde influended the egg weight, Haugh Unit and albumen index at chamber temperature during the storage. Soaking with 1% hydrogen peroxide showed the best results compared with the other treatments.<br />Key words: soaking, hydrogen peroxide, weight decrease, haugh unit, albumen index</p>

Photochemical reactions of bacteriorhodopsin in Triton X-100 solution studied by low temperature spectrophotometry

1985 ◽  
Vol 63 (7) ◽  
pp. 1891-1898 ◽  
Author(s):  
Tatsuo Iwasa ◽  
Fumio Tokunaga ◽  
Tỏru Yoshizawa
Keyword(s):  
Low Temperature ◽  
Thermal Equilibrium ◽  
Photochemical Reaction ◽  
Membrane Structure ◽  
Purple Membrane ◽  
Photochemical Reactions ◽  
The Other ◽  
Other Hand ◽  
Triton X

The photochemical reaction of purple membrane solubilized with Triton X-100 (T-BR) was investigated by low temperature spectrophotometry. The batho- and meta-intermediates of T-BR were observed to resemble bacteriorhodopsin in native purple membrane. Two photoproducts characteristic of the T-BR system were found, which were named the "490-nm complex" and the "380-nm complex". The 490-nm complex was in thermal equilibrium with T-BR in the dark. Cooling T-BR to low temperature favoured the 490-nm complex, which was photoinsensitive. On the other hand, the 380-nm complex was produced by warming the batho-intermediate and reverted to the original T-BR. The meta-intermediate of T-BR may possibly be in thermal equilibrium with the 380-nm complex. On the basis of the above results, the possible role of the membrane structure was discussed

Paraquat (Methylviologen): Its Interference with Primary Photochemical Reactions

1993 ◽  
Vol 48 (3-4) ◽  
pp. 374-378 ◽  
Author(s):  
Tetsuo Hiyama ◽  
Akira Ohinata ◽  
Shin-ichi Kobayashi
Keyword(s):  
Reaction Center ◽  
Electron Donor ◽  
Photosystem I ◽  
Photochemical Reaction ◽  
Photochemical Reactions ◽  
The Other ◽  
Primary Photochemical Reaction

Paraquat(methylviologen), a widely used nonspecific herbicide, is ptoreduced in the primary photochemical reaction of photosystemI. Using two types of the photosystem I reaction center preparations, i.e. one with FeSA/FeSB and the other without, the immediate electron donor to methylviologen was determined to be FeSx (P430) rather than FeSA/FeSB.

Detoxification of Citrinin and Ochratoxin A by Hydrogen Peroxide

1994 ◽  
Vol 77 (3) ◽  
pp. 631-637 ◽  
Author(s):  
Sophie G Fouler ◽  
Alka B Trivedi ◽  
Naofumi Kitabatake
Keyword(s):  
Hydrogen Peroxide ◽  
Ochratoxin A ◽  
Hela Cells ◽  
Room Temperature ◽  
The Other ◽  
Toxic Compound ◽  
Other Hand ◽  
Alkaline Conditions

Abstract The effects of hydrogen peroxide on citrinin and ochratoxin A toxicity were examined using HeLa cells. The citrinin was completely detoxified by prior incubation with 0.05% hydrogen peroxide for 30 min at room temperature, and the toxic compound(s) that resulted from heating citrinin at 100°C were also detoxified upon reheating it with hydrogen peroxide. On the other hand, ochratoxin A was not detoxified by hydrogen peroxide at room temperature, but its toxicity was reduced by heating ochratoxin A with hydrogen peroxide under alkaline conditions.

Study of Direct Synthesis of Hydrogen Peroxide Acid Solutions at a Heat-Treated MnCl–Porphyrin/Activated Carbon Cathode from H2 and O2

2012 ◽  
Vol 116 (7) ◽  
pp. 4572-4583 ◽  
Author(s):  
Ichiro Yamanaka ◽  
Takeshi Onizawa ◽  
Hirobumi Suzuki ◽  
Noriko Hanaizumi ◽  
Naoya Nishimura ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Direct Synthesis ◽  
Acid Solutions ◽  
Carbon Cathode ◽  
Heat Treated

One-electron photooxidation of N-ethylcarbazole in the presence of carbon tetrachloride. Products and mechanism of the photochemical reaction

1985 ◽  
Vol 63 (7) ◽  
pp. 1654-1665 ◽  
Author(s):  
Bogumil Zelent ◽  
Gilles Durocher
Keyword(s):  
Carbon Tetrachloride ◽  
Photochemical Reaction ◽  
Reaction Medium ◽  
Chloride Ion ◽  
Photochemical Reactions ◽  
The Other ◽  
Main Process ◽  
Reaction Products ◽  
Solvent Cage ◽  
Ct Complex

The mechanism of the photodecomposition of N-ethylcarbazole (NEC) in the presence of carbon tetrachloride has been discussed on the basis of the photoproducts identified. The photodissociation of the N-ethyl bond and the electron transfer in the transiently formed ex-CT complex, [Formula: see text], have been proposed as the primary photochemical processes involved irr the singlet excited NEC molecule. The latter, treated as the main process, leads to the radical cation of NEC, chloride ion, and trichloromethyl radical in the solvent cage, [NEC+•Cl−ĊCl3]. The other reactions in the system studied are analysed following the decomposition of NEC+• in the presence of Cl− and ĊCl3, which can occur by the N-ethyl group and (or) by the aromatic ring. The formation of intermediate products such as[Formula: see text]in the solvent cage gives rise to secondary photochemical reactions in the system studied. The polarity and chemical activity of the reaction media used strongly influence the nature of the secondary photochemical transformations both in and outside the solvent cage. The formation mechanism of the photochemical reaction products in CCl4 when ammonia was used, after and during irradiation, has been explained mainly by the transformations of the radical αr and cation αk as well as by the carbazyl radical β, which is also formed in the reaction medium. On the other hand, reaction of the cation [Formula: see text] explains the formation of the photoproducts in the irradiated solution of NEC with CCl4 in ethanol. These photochemical results have been compared to the photochemical reactions involved in the carbazole–CCl4 system.

scholarly journals Pengaruh Perendaman Telur dengan Larutan Hidrogen Peroksida terhadap Penurunan Bobot, Haugh Unit dan Indeks Putih Telur Itik Konsumsi Selama Penyimpanan pada Suhu Ruang

2017 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Nilawati Widjaya
Keyword(s):  
Hydrogen Peroxide ◽  
Weight Reduction ◽  
Room Temperature ◽  
The Other ◽  
Duncan Multiple Range Test ◽  
Egg Weight ◽  
Chamber Temperature ◽  
Weight Decrease ◽  
Range Test ◽  
Haugh Unit

<p>This objective of the research was to know the effect of soaking with hydrogen<br />peroxide on weight reduction, haugh unit and albumen index of duck eggs during storage at room temperature. The research was designed as Completely Randomize Design (CRD) wtih four treatments and six replicates each. The treatments were: soaking with aquades, soaking with 1, 2, and 3% of hydrogen The data were analyzed by analysis of variance and continued with Duncan Multiple Range Test. The results indicated that soaking with hydrogen peroxyde influended the egg weight, Haugh Unit and albumen index at chamber temperature during the storage. Soaking with 1% hydrogen peroxide showed the best results compared with the other treatments.<br />Key words: soaking, hydrogen peroxide, weight decrease, haugh unit, albumen index</p>

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

Understanding the risks and rewards of using 50% vs. 10% strength peroxide in pulp bleach plants

TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 601-607
Author(s):  
Alan Rudie ◽  
Peter Hart
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Rate ◽  
The Other ◽  
Mechanical Pulp ◽  
Engineering Controls ◽  
Point Of Use ◽  
Process Failure

The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant, it is recommended to dilute the peroxide to 10% prior to application, because risk does not outweigh the benefit. For point of use in a mechanical bleach plant, it is recommended to use 50% peroxide going into a bleach liquor mixing system that includes the other chemicals used to maintain the brightening reaction rate. When 50% peroxide is used, it is critical that proper engineering controls are used to mitigate any risks.

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