Search results for " oxidation"

Green Oxidation of Alcohols to Carbonyl Compounds by Heterogeneous Photocatalysis

2010

Titania Photocatalysts for Selective Oxidations in Water

2011

Heterogeneous photocatalysis by polycrystalline semiconductor oxides is an unconventional technology that has been mainly applied for the degradation of organic and inorganic pollutants in both the vapor and liquid phase. The application of photocatalysis in synthetic routes has also been researched in recent years, demonstrating its viability as an alternative route in organic chemistry. This work illustrates the main findings in the application of heterogeneous photocatalysis to the oxidation of organic compounds dissolved in water, free of any organic co-solvent. Two main aspects of the oxidative process have been studied: the first one is the partial oxidation of various mono-substitute…

Methane oxidation at a surface-sealed boreal landfill.

2009

Abstract Methane oxidation was studied at a closed boreal landfill (area 3.9 ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable layer into the top soil cover. Mean methane emissions at the 25 measuring points at four measurement times (October 2005–June 2006) were 0.86–6.2 m 3  ha −1  h −1 . Conservative estimates indicated that at least 25% of the methane flux entering the soil cover at the measuring…

Catalytic CO oxidation over pumice supported Pd–Ag catalysts

2001

Abstract Results on the catalytic oxidation of CO at 523 K over bimetallic Pd–Ag catalysts supported on pumice are reported and compared with those obtained from the monometallic Pd and Ag catalysts. The catalysts were prepared by organometallic precursors and were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) after different treatments with air and with hydrogen. The activity of the catalysts decreases with increasing Ag/Pd atomic ratio, the monometallic palladium exhibiting the highest activity. Furthermore, the treatment with air and with hydrogen always results in a better catalytic performance. On the basis of the structural characterization by XRD…

2017

A hybrid bioinspired material with manganese(II) complexes grafted on the surface of a mesostructured porous silica is investigated. The Mn sites mimic the manganese-dependent dioxygenase (MndD), which is an enzyme that catalyses the oxidation of catechol derivatives. The metal complexes were introduced in the silica using a dinuclear complex [Mn2L2(Cl)2(μ-Cl)2] as a precursor with a clickable ligand N,N′-bis[(pyridin-2-yl)methyl]prop-2-yn-1-amine (L). Azide moieties covalently grafted on MCM-41 type mesoporous silica were utilised to anchor the manganese complex through Huisgen cycloaddition using CuBr(PPh3)3 as a catalyst. A second functional group – trimethylsilyl or pyridine—was grafted…

The experimental herbicide UKJ72J is an inhibitor of succinate oxidation in plant mitochondria

1983

not received UKJ72J Herbicide Thiopyrimidine Plant mitochondria Inhibitor Succinate oxidation

Insights into the catalytic production of hydrogen from propane in the presence of oxygen: Cooperative presence of vanadium and gold catalysts

2015

7 figures.-- © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Stability of the lipid fraction of milk‐based infant formulas during storage

2005

A study is made of the effects of storage (time and temperature) on the lipid fraction of four milk-based adapted infant formulas with basically the same composition, though differing in the iron salt added (lactate or sulfate) and/or the vitamin E source (a-tocopherol or α-tocopherol acetate). Peroxide value, hydroperoxide C 18 percentage and thiobarbituric acid-reactive substance (TBARS) content were used as indicators of lipid peroxidation. Fat contents remained stable throughout storage. Peroxide values increased from the first storage month and were affected by storage time, although they exhibited irregular behavior. Storage time and temperature affected hydroperoxide percentage, whic…

A Comprehensive Review on Lipid Oxidation in Meat and Meat Products.

2019

Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Noneth…

Oxidative markers in children with severe obesity following low-calorie diets supplemented with mandarin juice

2010

Aim:  To evaluate the effect of supplementing a hypocaloric diet with mandarin juice, a food with a high content of antioxidants (vitamin C, flavonoids and carotenoids), on biomarkers of oxidant/antioxidant status of severe obese children. Methods:  Forty obese children were randomized into two groups pair-wise in a 4-week controlled intervention study. Both groups followed a hypocaloric diet. One group received additionally a supplementation of 500 mL of 100% mandarin juice daily. Clinical data, anthropometry, dietary intake and fasting blood samples were collected at baseline and after the intervention. Lipid peroxidation was assessed by circulating levels of malondialdehyde, and protein …