Oleum Fuming

The reconcentration of dilute (50—60%) sulfuric acid is one of the more costly operations in the manufacture of ethanol by this process. An acid reboiler, followed by a two-stage vacuum evaporation system, raises acid concentration to about 90%. The 90% acid is then brought to 96—98% strength by fortification with 103% oleum (fuming sulfuric acid). 

Nitrohydrochloric acid Perchloric acid Phenosulphonic acid Phosphorus pentoxide Propionic acid Selenic acid Spent acids Sulphamic acid Sulphuric acid and oleum (fuming sulphuric acid) Sulphurous acid Thioglycolic acid Trichloroacetic acid... 

Oleum, n. oleum, fuming sulfuric acid (in Latin Pharm. names) oil,... 

Oleum. Fuming sulfuric acid a soln of sulfur trioxide in sulfuric acid used as a sulfating and sulfonating agent. See under Acidity in Acids in Vol 1, A88-R to A90-R Acids Used in Manufacture and Analysis of Explosives in Vol 1, A93-L to A93-R and under Nitration in this Vol For analytical procedures, see under Glass Bulbs for Weighing Acids in Vol 6, G78-R to G79-R... 

In the final stage, the sulphur trioxide is absorbed in 98% sulphuric acid to form oleum (fuming sulphuric acid). 

PTFE, FEP and PFA are attacked only by alkaline metals and their organic derivatives elemental fluorine and chlorine trifluoride alkali and alkaline earth metals with their oxides and carbonates above 350°C. The other halogens, aqua regia, nitrosulfuric acid mixtures, oleum (fuming sulfuric acid) and solvents are without significant effects. 

OLEUM Fuming Sulfuric Acid Corrosive Material 3 0 2 W... 

Although the substance of the composition H2S207 is capable of definite existence, the commercial products deviate from the composition expressed by the formula and contain variable quantities of sulphuric acid with pyrosulphurie acid or of pyrosulphuric acid with sulphur trioxide. For the purpose of including all varieties of impure pyrosulphurie acid, the somewhat vague terms oleum, fuming sulphuric acid and Nordhausen sulphuric acid are advantageous. 

Sulfonic acids are prepared on a commercial scale by the sulfonalion of organic substrates using a variety of sulfonating agents, including sulfur trioxidc (diluted in air), sulfur trioxide (in sulfur dioxide), sulfuric acid, oleum (fuming sulfuric acid), chlorosulfuric acid, sulfamic add, trialkylamine-sulfur trioxide complexes, and sulfite ions. Other methods of sulfonic acid production, practiced on an industrial scale, include the oxidation of thiols, sulfide, disulfides, sulfoxides, sulfones, and sulfinic acids. See also Sulfonalion and Sulfation. 

Sulfonation is a bimolecular electrophilic substitution reaction (SE2) and the electrophile is sulfur trioxide.3a Sulfur trioxide is a powerful electrophile because of the electron-withdrawing effect of the three double-bonded oxygen atoms. Consequently, oleum (fuming sulfuric acid), which contains approximately 10% of excess sulfur trioxide, is a much more powerful sulfonating agent than concentrated sulfuric acid. Sulfur trioxide is a sufficiently powerful electrophile to attack benzene (23) directly. The mechanism of the sulfonation of benzene by hot concentrated sulfuric acid to give benzenesulfonic acid (24) is shown in Scheme 15.4a... 

OLEUM (FUMING SULFURIC ACID) See Sulfur trioxide Sulfuric acid... 

Oleum (fuming sulfuric acid) Oxidation catalyst made from porcelain Porchloric acid Peroxides, inorganic Phosphates, except defluorinated and ammoniated... 

Magnesium arsenide Martonite Methyl bromide Methyl fluoride Methyl mercaptan Methyl sulfate Molybdenum fluoride Nickel carbonyl Nitrogen peroxide Nitrogen trifluoride Nitrosomethylurethane Oleum (fuming sulfuric acid) Oxygen difluoride Paranitro benzyl chloride... 

The exact nature of the electrophile in sulfonation reactions seems to vary with the amount of water present. Certainly for oleum (fuming sulfuric acid, that is concentrated sulfuric acid with added sulfur trioxide) and solutions of sulfur trioxide in organic solvents, the electrophile is sulfur trioxide itself, SO3. With more water around, H3SOJ and even H2S2O7 have been suggested. 

Stanton and Staveley Ltd. (1975). Notes on the properties and handling of oleums (fuming sulphuric acids). 

The Chemical Emergency Preparedness and Prevention Office has estimated the zone of vulnerability under worst-case scenario conditions for facilities containing different hazardous substances. They conclude that for a facility containing toxic substances, the median distance from the facility to the outer edge of its vulnerable zone is 1.6 miles. Flammable substances have a worst-case scenario vulnerability zone whose median distance reaches 0.4 miles from the facility. However, many facilities reported vulnerability zones extending 14 miles from the facility (primarily for urban area releases of chlorine stored in 90-ton rail tank cars) and 25 miles (for rural releases of chlorine stored in 90-ton rail tank cars). Other chemicals for which the reported vulnerability zone equaled or exceeded 25 miles include anhydrous ammonia, hydrogen fluoride, sulfur dioxide, chlorine dioxide, oleum (fuming sulfuric acid). 

However molded graphite cannot be used to seal materials that would attack it chemically, such as aqua regia, perchloric acid, and oleum (fuming sulfuric acid) (see Ch. 3, Sec. 7.0). Sealing failure may also occur with abrasive materials such as chromic acid, chromic oxide, chrome plating compounds, potassium dichromate, sodium chromate, and sodium dichro-mate.Pl... 

The second incident, the least significant of the three incidents, involved oleum or fuming sulfuric acid which is a solution of sulfur trioxide in sulfuric acid. Oleum fumes are toxic and of course corrosive. At the Belle plant, oleum had been used in the production of methacrylic acid which is used for making acrylic polymers. 

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