Sulfuric acid, catalytic converter

Table 25.2 Typical compositions of wet sulfuric acid catalytic converter feed gas (Laursen and Karavanov, 2006) ...

In the early versions, ethylene cyanohydrin was obtained from ethylene chlorohydrin and sodium cyanide. In later versions, ethylene oxide (from the dkect catalytic oxidation of ethylene) reacted with hydrogen cyanide in the presence of a base catalyst to give ethylene cyanohydrin. This was hydrolyzed and converted to acryhc acid and by-product ammonium acid sulfate by treatment with about 85% sulfuric acid. 

The y -phenylenediamiaes are easily obtained by dinitrating, followed by catalyticaHy hydrogenating, an aromatic hydrocarbon. Thus, the toluenediamiaes are manufactured by nitrating toluene with a mixture of sulfuric acid, nitric acid, and 23% water at 330°C which first produces a mixture (60 40) of the ortho and para mononitrotoluenes. Further nitration produces the 80 20 mixture of 2,4- and 2,6-dinitrotoluene. Catalytic hydrogenation produces the commercial mixture of diamiaes which, when converted to diisocyanates, are widely used ia the production of polyurethanes (see Amines, aromatic, DIAMINOTOLUENES) (22). 

Phosphate fertilizer complexes often have sulfuric and phosphoric acid production facilities. Sulfuric acid is produced by burning molten sulfur in air to produce sulfur dioxide, which is then catalytically converted to sulfur trioxide for absorption in oleum. Sulfur dioxide can also be produced by roasting pyrite ore. Phosphoric acid is manufactured by adding sulfuric acid to phosphate rock. The... 

To get a complex set of substituents by direct derivatization of benzotriazole is not feasible. In such situations, it is better to have all the substituents in place first and later construct the heterocyclic ring. High reactivity of anilines and their well-developed chemistry makes them good stating materials. In an example shown in Scheme 215, acetanilide 1288 is nitrated to afford nitro derivative 1289 in 73% yield. Catalytic reduction of the nitro group provides methyl 4-acetylamino-3-amino-5-chloro-2-methoxybenzoate 1290 in 96% yield. Nitrosation of compound 1290 in diluted sulfuric acid leads to intermediate 1291, which without separation is heated to be converted to 7-chloro-4-methoxy-l//-benzotriazole-5-carboxylic acid 1292, isolated in 64% yield <2002CPB941>. 

SNOX A combined flue-gas desulfurization and denitrification process. The NOx is first removed by the SCR process, and then the S02 is catalytically oxidized to S03 and converted to sulfuric acid by the WSA process. Developed by Haldor Topsoe and first operated at a power station in Denmark in the 1990s. 

Polymerization units convert olefin feedstocks (primarily propylene) into higher octane polymers. These units generally consist of a feed treatment unit (to remove H2S, mercaptans, and nitrogen compounds), a catalytic reactor, an acid removal section, and a gas stabilizer. The catalyst is usually phosphoric acid, although sulfuric acid is used in some older methods. The catalytic reaction occurs at 150-224°C (300-435°F) and at a pressure of 11.2-137.0 atm (150-2000 psig). The temperature and pressure vary with the subprocess used. 

IsoquinoUne was converted to 1,2,3,4-tetrahydroisoquinoline in 89% yield by reduction with sodium in liquid ammonia and ethanol [473], and to a mixture of 70-80% cis- and 10% trans-decahydroisoquinoline by catalytic hydrogenation over platinum oxide in acetic and sulfuric acid [474]. Without sulfuric acid the hydrogenation stopped at the tetrahydro stage. Catalytic hydrogenation of isoquinoline and its derivatives is the topic of a review in Advances in Catalysis [439]. 

Reduction of lactams to amines resembles closely the reduction of amides except that catalytic hydrogenation is much easier and was accomplished even under mild conditions. a-Norlupinone (l-azabicyclo[4.4.0]-2-oxodecane) was converted quantitatively to norlupinane (l-azabicyclo[4.4.0]decane) over platinum oxide in 1.25% aqueous hydrochloric acid at room temperature and atmospheric pressure after 16 hours [1122]. Reduction of the same compound by electrolysis in 50% sulfuric acid over lead cathode gave 70% yield [1122]. 

Nitration of hydroxypropiophenone (7-1) followed by conversion of the phenol to its methyl ether by means of methyl iodide provides the intermediate (7-2) the nitro group is then reduced to the corresponding amine (7-3) by catalytic reduction. The newly introduced amine is then replaced by a nitrile group by successive conversion to the diazonium salt by means of nitrous acid followed by treatment with cuprous cyanide (7-4). Reaction with aluminum chloride removes the methyl ether to afford the ortho acylphenol (7-5). This is converted to the chromone (7-6) as above by reaction with benzoyl chloride and sodium benzoate. The nitrile is next hydrolyzed to the carboxylic acid (7-7) by means of sulfuric acid. The acid is then converted to its acid chloride by means of thionyl chloride and that treated with 2-(A -piperidyl)ethanol (7-8). There is thus obtained flavoxate (7-9) [8], a muscle relaxant whose name reflects its flavone nucleus. 

A number of dihalogenated aromatic amines have been conveniently converted into the corresponding nitroso compounds by room-temperature oxidation with peracetic acid with and without the presence of catalytic amounts of sulfuric acid. Care must be taken to maintain mild reaction conditions to prevent the conversion of the nitroso product into a nitro compound [84]. The example cited here for the preparation of 2,6-dichloronitrosobenzene dimer does afford an excellent yield. 

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