نتایج جستجو برای: acid sulfuric
تعداد نتایج: 747871 فیلتر نتایج به سال:
Sulfate esters have recently been identified in the secondary organic aerosol (SOA) formed in the photooxidation of biogenic hydrocarbons both in laboratory and under ambient atmospheric conditions. In the present study, the kinetics feasibility of direct reactions between alcohols and sulfuric acid to form sulfate esters in aerosol particles is explored. Nuclear magnetic resonance methods were...
A water vapor electrolysis cell utilizing sulfuric acid as the electrolyte has been shown to be capable of operating efficiently on the typical humidity of cabin air. Concentrated sulfuric acid can absorb enough water from a 50% relative humidity air stream at 75°F to permit an electrolysis cell to c&rate at a current density as high as 150 mA/cm2. . Sulfuric acid was examined for physical prop...
silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 by reaction with aromatic amines at room temperature in good to excellent yields. imidate was prepared by treatment of equimolar quantities of triethyl orthoformate and diaminomaleonitrile in refluxing dioxane. all the compounds were characterized fully by ...
the aryl-(z)-n-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...
a novel and safe method for nitration of phenols, anilines and other aromatic compounds has beenfound to be feasible with alumina sulfuric acid (asa) as catalyst and mg (no3)2.6h2o as nitrating agent inneat water as solvent. the use of water makes this method compatible with the green chemistry approach
cellulose sulfuric acid as a bio-polymer based solid catalyst efficiently catalyzes the selectively oxidation of sulfides to sulfoxides and thiols to disulfides using hydrogen peroxide as a green oxidant with good yields at room temperature. the developed method offers a number of advantages such as high selectivity, mild reaction conditions, simple operation, cleaner reaction profiles, low cos...
It is well established that the bacterium Thiobacillus thiooxidans is capable of growing in very strong mineral acid solutions and of producing, from elementary sulfur, sulfuric acid solutions more concentrated than 1 N and a reaction considerably below pH 1. This organism had been considered unique in its tolerance to acid until Starkey and Waksman (1943) demonstrated that certain fungi, Acont...
Isopropyl alcohol has been called the first petrochemical (IARC, 1992). It can be prepared via three different methods: indirect hydration of propylene, direct hydration of propylene, and catalytic hydrogenation of acetone. Indirect hydration, also called the sulfuric-acid process, was the only method used to produce isopropanol worldwide until the first commercial direct-hydration process was ...
a new model is proposed in this research to calculate the longitudinal strengthof unidirectional e-glass reinforced polymer composites exposed to sulfuricacid environment, using a micromechanics model. in the proposed method,it is assumed that the residual strength of the degraded composites under acidic environment can be calculated by knowing the degraded strength properties of the constituen...
The molecular processes leading to formation of nanoparticles of blue haze over forested areas are highly complex and not fully understood. We show that the interaction between biogenic organic acids and sulfuric acid enhances nucleation and initial growth of those nanoparticles. With one cis-pinonic acid and three to five sulfuric acid molecules in the critical nucleus, the hydrophobic organic...
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