Sulfuric acid reaction with copper

Among other color reactions of thiophene, the following may be mentioned Liebermann reaction with nitrite and sulfuric acid (73) the very sensitive reaction with thaline (tetrahydro-/ -hydroxyquinoline methyl ether) and dilute nitric acid (74) reaction with sulfuric acid, copper (II) acetate, and lactic acid (75) and, especially, the reaction with ceric ammonium nitrate (76). Of course, this reaction is not specific (see also p. 170), but it allows the differentiation of isomeric thiophene derivatives. 

Benzanthrone has been prepared by three general methods, the first of which is generally regarded as the best (i) by heating a reduction product of anthraquinone with sulfuric acid and glycerol,1 or with a derivative of glycerol, or with acrolein. The anthraquinone is usually reduced in sulfuric acid solution, just prior to the reaction, by means of aniline sulfate, iron, , or copper. It has also been prepared (2) by the action of aluminum or ferric chloride on phenyl-a-naphthyl ketone, and (3) from i-phenylnaphthalene-2-carboxylic acid. ... 

The various types of heterogeneous reactions are shown in Table 3.3. They are broadly grouped as solid-gas, solid-liquid, solid-solid, liquid-gas, and liquid-liquid reactions. The different types included in each group are also shown in the compilation. Some representative processes have been indicated as examples. It may be pointed out that in the group of solid-liquid reactions a specific mention of what is known as autocatalytic reactions has not been made. The autocatalytic processes occur when the liquid product reacts further with the solid undergoing reaction. The dissolution of copper in dilute sulfuric acid (or aqueous ammonia) in the presence of oxygen may be cited as an example ... 

Methylpropene can be removed from the reaction mixture by distillation and easily is made the principal product by appropriate adjustment of the reaction conditions. If the 2-methylpropene is not removed as it is formed, polymer and oxidation products become important. Sulfuric acid often is an unduly strenuous reagent for dehydration of tertiary alcohols. Potassium hydrogen sulfate, copper sulfate, iodine, phosphoric acid, or phosphorus pentoxide may give better results by causing less polymerization and less oxidative degradation which, with sulfuric acid, results in the formation of sulfur dioxide. 

An additional cleanup step should be performed to remove sulfur using mercury or copper powder. Permanganate-sulfuric acid treatment is not recommended. Unlike PCBs, most pesticides are fully or partially oxidized by reaction withKMn04-H2S04. Treatment with concentrated H2S04 alone is not recommended, because pesticides such as dieldrin and endrin were found to be totally destroyed at 20 ng/mL and endrin aldehyde and endosulfan sulfate partially decomposed at 60 ng/mL concentrations, respectively, in the extract (Cavanaugh and Patnaik, 1995). 

Dimethyl terephthalate is manufactured from terephthalic acid or directly from p-xylene. Esterification of terephthalic acid with methanol occurs with sulfuric acid as the acid catalyst. Direct oxidation of p-xylcnc with methanol present also produced dimethyl terephthalate copper salts and manganese salt are catalysts for this reaction. The dimethyl terephthalate (boiling point 288°C, melting point 141°C) must be carefully purified via a five-column distillation system. 

The main requirement to methylchloride, ethylchloride and chlorobenzene is the absence of impurities, by-products and especially moisture. With even the slightest amount of liquid entering the reaction zone, the products start to hydrolyse and condense, the activity of the contact mass or copper-silicon alloy decreases, and the process subsides. That is why the technology of direct synthesis usually provides for a device to dehydrate alkyl- and arylchlorides. For this purpose one can pass methyl- or ethylchloride through the tower sprayed with sulfuric acid, or use other dehydrating substances (burnt CaCF, AI203 and zeolites, e.g. burnt klinoptilo-lite). 

The decomposition of the lower sulfides of the heavy metals and the recovery of the metal as soluble salts and of sulfur in the elemental form have been demonstrated for pyrite, pyrrhotite, chalcopyrite, sphalerite, galena, molybdenite, and associated metals such as nickel and cobalt. Pyrite and chalcopyrite are higher sulfides and to be amenable to this treatment have to be thermally decomposed at 600-650 C prior to leaching. The reactions with nitric acid are exothermic, and are carried out below 1 atm and at around 100°C. In addition to the sulfides, this technique has been applied successfully to the extraction of nonferrous metals from partly oxidized sulfide ores, fayalite slags, copper scrap, and other intermediate products, such as residue from electrolytic zinc plats. 

Zinc blende, galena and copper pyrites are important raw material sources in the Federal Republic of Germany. These ores are utilized in the extraction of metals with sulfuric acid being produced as a byproduct, so-called metal acid. As a result of increased efforts in environmental protection, the proportion of recycled sulfuric acid e.g. from nitration reactions or oil refineries, has increased significantly in the last 20 years. 

Hydrofluoric acid is the most basic common precursor of most fluorochemicals. Aqueous hydrofluoric acid is prepared by reaction of sulfuric acid with fluorspar (CaF2). Because HF etches glass with formation of silicon tetrafluoride, it must be handled in platinum, lead, copper. Monel (a Cu-Ni alloy developed during the Manhattan Project), or plastic (e.g. polyethylene or PTFE) apparatus. The azeotrope contains 38 % w/w HF and it is a relatively weak acid (pfC 3.18, 8 % dissociation), comparable with formic acid. Other physicochemical properties of hydrofluoric acid are listed in Table 1.2. 

IRON PERSULFATE (10028-22-5) Fe2(S04)3 Light sensitive. Hygroscopic hydrolyzed slowly in water , forming acid solution and precipitates hydroxide and phosphate salts. Violent reaction with strong bases. Aqueous solution (often shipped as 73% solution) is incompatible with sulfuric acid, aluminum, caustics, alkylene oxides, ammonia, aliphatic amines, alkanolamines, amides, epichlorohydrin, organic anhydrides, isocyanates, magnesium, methyl isocyanoacetate, vinyl acetate. Corrosive to copper, copper alloys, and both mild and galvanized steel. 

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