The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Philip Hodge - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of isopropyl-substituted anthraquinones via Friedel-Crafts acylations: migration of isopropyl groups.
Royal Society Open Science, 2017Co-Authors: Abdel B. Chakiri, Philip HodgeAbstract:Friedel–Crafts reactions of isopropyl-substituted benzenes with phthalic anhydride in the presence of aluminium trichloride, followed by cyclization of the products with Strong Sulfuric Acid give, ...
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Synthesis of isopropyl-substituted anthraquinones via Friedel-Crafts acylations: migration of isopropyl groups.
Royal Society open science, 2017Co-Authors: Abdel B. Chakiri, Philip HodgeAbstract:Friedel-Crafts reactions of isopropyl-substituted benzenes with phthalic anhydride in the presence of aluminium trichloride, followed by cyclization of the products with Strong Sulfuric Acid give, as expected, anthraquinones. The syntheses, however, often afford more than one anthraquinone. In some cases the isopropyl groups migrate cleanly to other ring positions; in other cases they are lost.
Abdel B. Chakiri - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of isopropyl-substituted anthraquinones via Friedel-Crafts acylations: migration of isopropyl groups.
Royal Society Open Science, 2017Co-Authors: Abdel B. Chakiri, Philip HodgeAbstract:Friedel–Crafts reactions of isopropyl-substituted benzenes with phthalic anhydride in the presence of aluminium trichloride, followed by cyclization of the products with Strong Sulfuric Acid give, ...
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Synthesis of isopropyl-substituted anthraquinones via Friedel-Crafts acylations: migration of isopropyl groups.
Royal Society open science, 2017Co-Authors: Abdel B. Chakiri, Philip HodgeAbstract:Friedel-Crafts reactions of isopropyl-substituted benzenes with phthalic anhydride in the presence of aluminium trichloride, followed by cyclization of the products with Strong Sulfuric Acid give, as expected, anthraquinones. The syntheses, however, often afford more than one anthraquinone. In some cases the isopropyl groups migrate cleanly to other ring positions; in other cases they are lost.
Michael S. Moats - One of the best experts on this subject based on the ideXlab platform.
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Dehydrating air and gases with Strong Sulfuric Acid
Sulfuric Acid Manufacture, 2013Co-Authors: Matthew J. King, William G. Davenport, Michael S. MoatsAbstract:SO2-bearing gas must be dry before it goes to catalytic SO2 oxidation. Otherwise, the SO3 made by catalytic oxidation will react with the gas's H2O(g) to form corrosive liquid Sulfuric Acid in cool flues and heat exchangers, especially during shutdowns. This problem is avoided by dehydrating (i) sulfur burning air and (ii) scrubbed metallurgical/spent Acid furnace off-gas by contacting these gases with Strong Sulfuric Acid. Dehydration is represented by the reaction: H2Og+H2SO4linStrongAcid→H2SO4·H2OlinslightlyweakenedAcid Industrially, the process is carried out in brick-lined stainless steel towers packed with ceramic saddles. Acid descends around the saddles where it meets and reacts with ascending H2O(g)-laden gas.
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Acid temperature control and heat recovery
Sulfuric Acid Manufacture, 2013Co-Authors: Matthew J. King, William G. Davenport, Michael S. MoatsAbstract:H2SO4(l) is made by the reaction of SO3 with the H2O(l) in Strong Sulfuric Acid. Heat is released by the reaction, so that H2SO4 making’s output Sulfuric Acid is ~ 25 K warmer than its input Acid. Output Acid temperature increases markedly with increasing input Acid temperature and decreasing Acid circulation rate. Corrosion rates increase with increasing temperature so that excessive temperatures must be avoided. They are avoided by cooling the recycled Acid in water cooled “shell and tube” or “plate and frame” heat exchangers. Acid plants (especially sulfur burning plants) are now often built with “Acid-sensible-heat-to-steam” energy recovery systems. These significantly increase Acidmaking energy efficiency.
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Regeneration of spent Sulfuric Acid
Sulfuric Acid Manufacture, 2013Co-Authors: Matthew J. King, William G. Davenport, Michael S. MoatsAbstract:Sulfuric Acid is used as a catalyst in gasoline, jet fuel, and polymer manufacture. The Sulfuric Acid catalyst is not consumed, but it becomes ineffective as it absorbs water, hydrocarbons, and other chemicals over time. Its catalytic properties are maintained by bleeding off some of the contaminated “spent” Acid and regenerating it to high purity 98% H2SO4() Sulfuric Acid. The spent Acid bleed is recycled and made into new Acid by (a) decomposing its H2SO4() to SO2, O2, and H2O(g) in a hot (1000 °C), mildly oxidizing furnace (b) removing dust and condensing water from the decomposition furnace’s offgas (c) adding air (d) dehydrating the gas with Strong Sulfuric Acid (e) catalytically oxidizing the gas’s SO2 to SO3 (f) making new, Strong Sulfuric Acid from (e)’s SO3.
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Production of H 2 SO 4 (ℓ) from SO 3 (g)
Sulfuric Acid Manufacture, 2013Co-Authors: Matthew J. King, William G. Davenport, Michael S. MoatsAbstract:The final step in Sulfuric Acid manufacture is the production of H2SO4(l) from SO3-bearing gas. The H2SO4 is made by sending Strong Sulfuric Acid down around ceramic saddles in a packed bed while blowing SO3 gas up through the bed. SO3 in the ascending gas reacts with H2O(l) in the descending Acid to produce strengthened Sulfuric Acid, i.e., SO3ginSO3,O2,N2gas+H2Olin98.5mass%H2SO4,1.5mass%H2OSulfuricAcid→80-110°CH2SO4linstrengthenedSulfuricAcid~99mass%H2SO4 The strengthened Acid is mostly diluted and sold. Some is recycled to the dehydration and absorption towers. Most Sulfuric Acid plants are double contact plants. They efficiently oxidize their feed SO2 to SO3 and efficiently make the resulting SO3 into H2SO4(l). Single contact plants are simpler and cheaper, but their exit gases contain more SO2.
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Metallurgical Offgas Cooling and Cleaning
Sulfuric Acid Manufacture, 2007Co-Authors: Matthew J. King, William G. Davenport, Michael S. MoatsAbstract:About 30% of the world's Sulfuric Acid is made from the SO2 in smelter and roaster offgases. These gases contain 10-75 volume% SO2. Their SO2 is suitable for making Sulfuric Acid, but the gases must be cooled, cleaned, diluted, and dried before being sent to Acidmaking. Cooling is usually done in a heat recovery boiler—which cools the gas and recovers its heat as steam. Considerable dust is removed in this heat recovery boiler. Additional dust and unwanted vapors are removed from the gas by subsequent electrostatic precipitation and aqueous scrubbing. Finally, H2O(g) is removed by (i) condensation and (ii) dehydration with Strong Sulfuric Acid. The gas is then ready for catalytic SO2 oxidation and H2SO4 making.
Jaroslav Stejskal - One of the best experts on this subject based on the ideXlab platform.
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Raman spectroscopy of polyaniline and oligoaniline thin films
Electrochimica Acta, 2014Co-Authors: Miroslava Trchova, Zuzana Morávková, Michal Bláha, Jaroslav StejskalAbstract:Abstract Polyaniline or oligoanilines were deposited in situ as thin films on non-conducting silicon supports during the chemical oxidation of aniline with ammonium peroxydisulfate in various aqueous media. When the polymerization was carried out in the solution of Strong (Sulfuric) Acid, polyaniline films having a globular morphology were obtained. In the solutions of weak (acetic or succinic) Acids or in water, the films composed of polyaniline nanotubes were produced. The oxidation of aniline under alkaline conditions yielded aniline oligomers with microspherical morphology. Infrared spectra suggest that the oligomers produced at the beginning of the oxidation are similar regardless of the Acidity of the medium, but this method was not able to elucidate the details of their molecular structure. A new insight into the structure of the early products of aniline oxidation based on their Raman spectra is reported. The influence of smooth gold support on the Raman spectra of the films has also been studied.
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polyaniline the infrared spectroscopy of conducting polymer nanotubes iupac technical report
Pure and Applied Chemistry, 2011Co-Authors: Miroslava Trchova, Jaroslav StejskalAbstract:Polyaniline (PANI), a conducting polymer, was prepared by the oxidation of ani- line with ammonium peroxydisulfate in various aqueous media. When the polymerization was carried out in the solution of Strong (Sulfuric) Acid, a granular morphology of PANI was obtained. In the solutions of weak (acetic or succinic) Acids or in water, PANI nanotubes were produced. The oxidation of aniline under alkaline conditions yielded aniline oligomers. Fourier transform infrared (FTIR) spectra of the oxidation products differ. A group of par- ticipants from 11 institutions in different countries recorded the FTIR spectra of PANI bases prepared from the samples obtained in the solutions of Strong and weak Acids and in alkaline medium within the framework of an IUPAC project. The aim of the project was to identify the differences in molecular structure of PANI and aniline oligomers and to relate them to supramolecular morphology, viz. the nanotube formation. The assignment of FTIR bands of aniline oxidation products is reported.
Tawfik M. Ahmed - One of the best experts on this subject based on the ideXlab platform.
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Active/Passive Behavior of Copper in Strong Sulfuric Acid
Journal of The Electrochemical Society, 1998Co-Authors: Desmond Tromans, Tawfik M. AhmedAbstract:A combination of thermodynamic analyses and potentiodynamic polarization tests have been used to study the anodic behavior of Cu in Strong H{sub 2}SO{sub 4} solutions in the concentration range 1--10 M. The studies were supplemented by chemical analyses of surface films. It was found that concentration-dependent changes in the activity of water played a major role in determining the anodic behavior and relative stability of corrosion product films. The anodic Tafel slope decreased from {approximately} 41 to {approximately} 31 mV with increasing Acid concentration. The onset of limiting current and active-passive behaviors at higher potentials was determined by the formation of films of hydrated copper sulfate, CuSO{sub 4} {center_dot} xH{sub 2}O, and not by formation of oxides. Limiting current behavior was observed in 1 M solutions, where the degree of hydration was x = 5. Well-developed passivity occurred in 10 M solutions where x = 1. The results are relevant to industrial electrorefining operations for Cu and indicate that chloride contamination, if present in sufficient amounts, could cause the premature onset of limiting current behavior (anode passivity) during refining.
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active passive behavior of copper in Strong Sulfuric Acid
Journal of The Electrochemical Society, 1998Co-Authors: Desmond Tromans, Tawfik M. AhmedAbstract:A combination of thermodynamic analyses and potentiodynamic polarization tests have been used to study the anodic behavior of Cu in Strong H{sub 2}SO{sub 4} solutions in the concentration range 1--10 M. The studies were supplemented by chemical analyses of surface films. It was found that concentration-dependent changes in the activity of water played a major role in determining the anodic behavior and relative stability of corrosion product films. The anodic Tafel slope decreased from {approximately} 41 to {approximately} 31 mV with increasing Acid concentration. The onset of limiting current and active-passive behaviors at higher potentials was determined by the formation of films of hydrated copper sulfate, CuSO{sub 4} {center_dot} xH{sub 2}O, and not by formation of oxides. Limiting current behavior was observed in 1 M solutions, where the degree of hydration was x = 5. Well-developed passivity occurred in 10 M solutions where x = 1. The results are relevant to industrial electrorefining operations for Cu and indicate that chloride contamination, if present in sufficient amounts, could cause the premature onset of limiting current behavior (anode passivity) during refining.
