Search results for "Hydroxyacetone"
showing 10 items of 10 documents
Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of pm<sub>2.5</sub> from xi'an, northwestern c…
2018
Abstract. The sources, formation mechanism and amount of organosulfates (OS) in atmospheric aerosol are not yet well understood, partly due to the lack of authentic standards for quantification. In this study, we report an improved robust procedure for the synthesis of organosulfates with different functional groups. Nine authentic organosulfate standards were synthesized and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate, and hydroxyacetone sulfate) were used to quantify their ambient concentrations. The authentic standards and ambient aerosol samples were analyzed using an optimized ultra performance liquid chromatography–electrospray ionization-tandem mass spectrom…
On the Mechanistic Origins of the pH-Dependency in Au-Catalyzed Glycerol Electro-Oxidation: Insight from First Principles Calculations
2021
Electrocatalytic oxidation of glycerol (EOG) is an attractive approach to convert surplus glycerol to value-added products. Experiments have shown that EOG activity and selectivity depend on the electrocatalyst, but also on the electrode potential, the pH, and the electrolyte. For broadly employed gold (Au) electrocatalysts, experiments have demonstrated high EOG activity under alkaline conditions with glyceric acid as a primary product, whereas under acidic and neutral conditions Au is rather inactive producing only small amounts of dihydroxyacetone. In the present computational work, we have performed an extensive mechanistic study to understand the pH- and potential-dependency of Au-cata…
Enzymes for the NADPH-dependent reduction of dihydroxyacetone and D-glyceraldehyde and L-glyceraldehyde in the mould Hypocrea jecorina
2006
The mould Hypocrea jecorina (Trichoderma reesei) has two genes coding for enzymes with high similarity to the NADP-dependent glycerol dehydrogenase. These genes, called gld1 and gld2, were cloned and expressed in a heterologous host. The encoded proteins were purified and their kinetic properties characterized. GLD1 catalyses the conversion of d-glyceraldehyde and l-glyceraldehyde to glycerol, whereas GLD2 catalyses the conversion of dihydroxyacetone to glycerol. Both enzymes are specific for NADPH as a cofactor. The properties of GLD2 are similar to those of the previously described NADP-dependent glycerol-2- dehydrogenases (EC 1.1.1.156) purified from different mould species. It is a reve…
A Combined Theoretical and Experimental Approach for Platinum Catalyzed 1,2-Propanediol Aqueous Phase Reforming
2017
Decomposition pathways of 1,2-propanediol (1,2-PDO) on platinum were investigated by means of experiments and quantum-mechanical calculations. Different reaction paths on a Pt(111) model surface were computationally screened. Gas and liquid phase products distribution for aqueous phase reforming of 1,2-PDO solutions was experimentally analyzed. A mechanistic approach was used to trace the preferred paths according to calculated activation barriers of the elementary steps; in this way, the presence or absence of some hypothesized intermediates in the experiments was computationally rationalized. Hydroxyacetone was demonstrated to be among the most favored decomposition products. The competit…
Copurification of dihydroxyacetone-phosphate acyl-transferase and other peroxisomal proteins from liver of fenofibrate-treated rats.
1997
Dihydroxyacetone-phosphate acyl-transferase (DHAP-AT), a peroxisomal membrane-bound enzyme that catalyzes the first step of ether-glycerolipid synthesis, was purified from liver of rats treated with fenofibrate, a peroxisome proliferator. The protocol first included isolation of peroxisomes, their purification through a discontinuous gradient and solubilization of membranes in CHAPS. DHAP-AT was further purified by four chromatographic steps, namely low-pressure size-exclusion, cation-exchange, hydroxylapatite and chromatofocusing. The chromatofocusing step led to a 4000-fold increase in the specific activity of DHAP-AT with respect to the liver homogenate with a yield of about 0.2%. Trypsi…
In situ hybridization of dihydroxyacetone phosphate acyltransferase, the regulating enzyme involved in plasmalogen biosynthesis
2005
International audience; In situ hybridization can be carried out using different methods. The experimenter has to choose various parameters: the type of tissue fixation, the time of incubation, and the duration of the exposure time. All these parameters are determinant for the sensitivity and the resolution of this technique. This publication of technical aspects described different experiments performed for in situ hybridization on liver tissue. We may conclude on the parameters to optimize each step of the hybridization procedure. Moreover, this technique could be transposed to the brain and applied to little structures with a light expression of DHAP-AT.
Die α-Glycerophosphat-Oxydation des Heuschreckenbrustmuskels (Locusta migratoria)
1956
The conditions were studied for the glycerophosphate oxidation by homogenate from locust flight muscle, and the O2-consumption was measured. Maximal oxidation rates were found with 0.087m glycerophosphate, 8 × 10−6m cytochromec, 7 × 10−6m DPN and pH 7.5. The production of dihydroxyacetone phosphate is followed by further oxidation steps, as could be shown by estimation of the different fractions of acid-soluble phosphate. Comparative studies were made on different insects and vertebrates. The rate of succinate oxidation by insect muscle was found to be ten times higher than that of vertebrate muscle. The relation of glycerophosphate oxidation to succinate oxidation is quite different in ins…
Production of ethyl lactate by activated carbon-supported Sn and Zn oxide catalysts utilizing lignocellulosic side streams
2021
Abstract In this study, activated carbon-supported Sn and Zn oxide catalysts were prepared from hydrolysis lignin and used for the conversion of model solutions of trioses, hexoses, and lignocellulosic biomass hydrolysates to ethyl lactate. Both catalysts, SnO2@AC and ZnO@AC, were able to produce ethyl lactate in high yields. SnO2@AC was a more active and selective catalyst in triose (dihydroxyacetone) conversion, providing 99% yield to ethyl lactate. ZnO@AC, by contrast, was more selective in glucose and hydrolysate conversion, with a yield of 60% and 85%, respectively. The ethyl lactate yields were significantly higher than those from the optimized model solution experiments when using Zn…
In situ ATR-IR studies in aqueous phase reforming of hydroxyacetone on Pt/ZrO2 and Pt/AlO(OH) catalysts: The role of aldol condensation
2018
Abstract In situ Attenuated Total Reflection Infrared (ATR-IR) spectroscopy was used to study Aqueous Phase Reforming of hydroxyacetone on Pt/AlO(OH) and Pt/ZrO2 catalysts at 230 °C/ 30 bar. Formation of strongly adsorbed aldol condensation products was observed on the surface of Pt/ZrO2 and ZrO2 in contrast to Pt/AlO(OH) and AlO(OH). Peak assignments were supported by DFT calculations of the IR spectra of the condensation products in vacuum and in the presence of water. Aldol condensation of hydroxyacetone leading to compounds with high molecular weight with unsaturated bonds was suggested as a first step in coke formation. Carbonaceous deposits on the surface of the ZrO2 support are oxyge…
Imidazol-4-carbinole aus Iminoestern und Dihydroxyaceton. 2. Mitt. über Imidazolsynthesen mit flüssigem Ammoniak
1974
Imidazol-4-carbinole 3 mit funktionellen Gruppen am C-Atom 2 lassen sich aus Iminoestern 1 und Dihydroxyaceton (2) in flussigem Ammoniak unter Druck darstellen. Imidazole-4-carbinols from Iminoesters and Dihydroxyacetone Imidazole-4-carbinols 3 with functional groups at C-atom 2 are obtained from iminoesters 1 and dihydroxyacetone (2) in liquid ammonia under pressure.