Strong acids sulfuric acid

Concentrated nitric acid can effect nitration but it is not as reactive as a mixture of nitric acid with sulfuric acid. The active nitrating species in both media is the nitronium ion, NOz+, which is formed by protonation and dissociation of nitric acid. The concentration of NOz+ is higher in the more strongly acidic sulfuric acid than in nitric acid. 

A high number of [l,3,4]thiadiazolo[2,3-c][l,2,4]triazinones 220 have been prepared by treatment of the fV-aminomer-captotriazine 218 with various acids. The cyclization proceeds in the presence of strong acid (sulfuric acid, phosphorus oxychloride) in good to large yields. Information (R and R1 groups, reaction conditions, yield, and references) concerning 46 different representatives of the heterocycle 220 obtained by this method are compiled in Table 7. 

Both the acidic character and the covalent character of different oxides of the same element increase with increasing oxidation number of the element. Thus, sulfur(VI) oxide (S03) is more acidic than sulfur(IV) oxide (S02). Reaction of S03 with water gives a strong acid (sulfuric acid, H2SC>4), whereas reaction of S02 with water yields a weak acid (sulfurous acid, H2S03). The oxides of chromium exhibit the same trend. Chromium(VI) oxide (Cr03) is acidic, chromium(III) oxide (Cr203) is amphoteric, and chromium(II) oxide (CrO) is basic. 

Many papers contain aluminum salts such as aluminum sulfate and aluminum nitrate. These are salts derived from a weak base, aluminum hydroxide, and strong acids, sulfuric acid and nitric acid, respectively. This combination produces acidic salts. The paper becomes acidic when the aluminum salts react with water in the air to form acids. Most paper contains these salts because aluminum salts prevent ink from soaking into paper. Paper made with calcium carbonate, a fairly neutral salt since it is derived from a weak acid (carbonic acid) and a weak base (calcium hydroxide), will not readily react with water in air. They are acid-free. Acid-free papers do not easily discolor and disintegrate. 

The first steps are the formation of a very powerful electrophile, none other than NO2. by the interaction of the two strong acids. Sulfuric acid is the stronger and it protonates the nitric acid on the OH group so that a molecule of water can leave. 

Sulfur dioxide dissolves to form the strong acid, sulfurous acid, so is strongly acidifying at very low concentrations. For example, for /7SO2 = 10 atm (a value much higher than concentrations now occurring owing to air pollution control measures in developed countries. Note, however, that low-pH rainfall still occurs as a result of incorporation of sulfuric and nitric acids). 

Dehaen et al. [100,101] found another interesting way to synthesize the IC backbone. They first used a condensation of indole and aldehyde in the presence of iodine in acetonitrile to afford 3,3,-bis(indolyl)mclhanc. The IC moiety was obtained by treating the previous compound with triethyl orthoformate and a catalytic amount of a strong acid (sulfuric acid or methanesulfonic... 

DIPROPYL OXIDE (111-43-3) CeHj O Highly flammable, peroxidizable liquid. Forms explosive mixture with air (flash point 70°F/21°C Fire Rating 3). Forms xmstable and explosive peroxides, especially when anhydrous. Reacts violently with oxidizers, permanganates, peroxides and hydroperoxides, ammonium persulfate, bromine dioxide, acyl halides, strong acids sulfuric acid, nitric acid. On small fires, use dry chemical powder (such as Purple-K-Powder), alcohol-resistant foam, or COj extinguishers. 

HEXANEDIOL (107-41-5) CsH O, Combustible liquid. Forms explosive mixture with air (flash point 204°F/96°C Fire Rating 1). Inconpatible with strong oxidizers, strong acids sulfuric acid, nitric acid, caustics, aliphatic amines, isocyanates. 

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