Sulfuric acid experimental

Nitroanthraquinone is prepared from anthraquinone by nitration in sulfuric acid (11), or in organic solvent (12). Nitration in nitric acid is dangerous. The mixture of anthraquinone and nitric acid forms a Sprengel mixture (13,14) which may detonate. However, detonation can be prevented by a dding an inert third component such as sulfuric acid. Experimental results of the steel-tube detonation tests for the anthraquinone—HNO2—H2SO4 system have been pubUshed (13). 

Hong, S-D., et al. (2008), A High Pressure and High Temperature Sulfuric Acid Experimental System , Trans. Korean Nuc. Soc. Autumn Mtg., Pyeongchang, Korea, 30-31 October. 

SAFETY PROFILE Fairly large doses of sulfites can be tolerated since they are rapidly oxidized to sulfates, although if swallowed they may cause irritation of the stomach by liberating sulfurous acid. Experimentally, large doses of sodium sulfite have been shown to cause retarded growth, nerve irritation, atrophy of bone marrow, depression, and paralysis. They will react with water, steam, or acids to produce a toxic and corrosive material. When heated to decomposition they emit highly toxic fumes of SO,. 

The similar C-H o-bond activation by platinum(II) sulfonate complex was theoretically investigated [36-38]. This is a model of the methane-to-methanol conversion by the platinum(II) complex in dry sulfuric acid experimentally reported [3]. There are two possible reaction courses in the C-H o-bond activation one is the oxidative addition of the C-H o-bond to the platinum(II) complex and the other is the metathesis of the C-H o-bond with the Pt-OSOjH moiety. Hush et al. proposed that the C-H o-bond activation took place through the oxidative addition to the platinum(II) complex [36]. This is not surprising because the oxidative addition of methane to the coordinatively unsaturated platinum(II) complex is not very difficult, as discussed above. However, Ziegler et al. reported that the metathesis could take place with the similar activation barrier to that of the oxidative addition [37]. Recently, Goddard et al. clearly concluded that the metathesis more easily proceeded than the oxidative addition in sulfuric acid [38]. They investigated this reac-... 

Fig. 4.11 Sulfuric acid experimental washing (dynamic effect)...

FIGURE 12.11 Nyquist plots of methanol oxidation at 80 °C and 0.35 V, 0.45 V, 0.55 V, and 0.65 V (vs. NHE) for an electrode with 40 wt.% Pt Ru (1 1 atomic ratio) on Vulcan XC-72 in l.Omoldm methanol and l.Omoldm sulfuric acid. Experimental data (symbols) and fitted results for equivalent circuit model (ECM) curves (solid lines) [24]. (For color version of this figure, the reader is referred to the online version of this book.)... 

That numerous 2-amino-5-nitrothiazole derivatives exhibit antiamebic, antihistomonal, antitrichomonal, and antischistosomal properties (see Section VI.2) explains the large number of nitration reactions reported. Nitration in a mixture of concentrated nitric and concentrated sulfuric acids IS among the most common experimental methods (16, 27, 58, 374-377). 

Experimental requirements for the isolation of these nitramino derivatives are developed in Ref. 87. They rearrange easily to ring nitro-substituted isomers (see Section V.6). In the 2-aminothiazole series, nitration may proceed through direct electrophilic substitution competing with rearrangement of nitramino derivatives. Dickey et al. have shown that the rearrangement proceeds rapidly in 96% sulfuric acid at 2(fC, but in 85% sulfuric add it is very slow so. according the concentration of add various mechanisms can participate in the formation of the 5-nitro derivative. 

Halogenation of 2-aminothiazole and derivatives has been reported under a wide variety of experimental conditions in water (161, 405. 406) in aqueous acids (16. 172, 407, 408) in solvents such as chloroform (27. 172), carbon disulfide (162, 166. 320. 409). benzene (165), acetic acid (410-413, 1580). or hydrochloric acid (414) or in 20% sulfuric acid (415-417). 

MO calculations of the cinnoline ring system show that the relative order of reactivities for electrophilic substitution is 5=8>6 = 7>3 4. This is confirmed experimentally, as nitration of cinnoline with a mixture of nitric and sulfuric acids affords 5-nitrocinnoline (33%) and 8-nitrocinnoline (28%). Similarly, 4-methylcinnoline gives a mixture of 4-methyl-8-nitrocinnoline (28%) and 4-methyl-5-nitrocinnoline (13%). 

Experimentally, both modes probably should be tried. In the alkylation of C4S with sulfuric acid, For instance, the continuous emulsion of acid produces a much better product and consumes less acid. 

Sonic agglomerators, which have been used experimentally for sulfuric acid mists and as mist eliminators. Commercial development is not projected at this time because the energy requirements are considerably greater than those for venturi scrubbers of similar capacity. 

Methyl-4-nitropyridine-l-oxide has been prepared by the nitration of 3-methylpyridine-l-oxide hydrochloride with a mixture of concentrated sulfuric acid and potassium nitrate. The I)reparation of this compound has been mentioned briefly by Talikowa, but no experimental details have been given. 

Experimental observations indicate that acid strength significantly affects the reaction rate. For example, sulfuric acid promotes nucleophilic substitution of alcohols by bromide, but acetic acid does not. How would a change in acid strength affect your calculated reaction energies ... 

The acid cleavage of the aryl— silicon bond (desilylation), which provides a measure of the reactivity of the aromatic carbon of the bond, has been applied to 2- and 3-thienyl trimethylsilane, It was found that the 2-isomer reacted only 43.5 times faster than the 3-isomer and 5000 times faster than the phenyl compound at 50,2°C in acetic acid containing aqueous sulfuric acid. The results so far are consistent with the relative reactivities of thiophene upon detritia-tion if a linear free-energy relationship between the substituent effect in detritiation and desilylation is assumed, as the p-methyl group activates about 240 (200-300) times in detritiation with aqueous sulfuric acid and about 18 times in desilylation. A direct experimental comparison of the difference between benzene and thiophene in detritiation has not been carried out, but it may be mentioned that even in 80.7% sulfuric acid, benzene is detritiated about 600 times slower than 2-tritiothiophene. The aforementioned consideration makes it probable that under similar conditions the ratio of the rates of detritiation of thiophene and benzene is larger than in the desilylation. A still larger difference in reactivity between the 2-position of thiophene and benzene has been found for acetoxymercuration which... 

This approach explains the experimental fact that the complete decomposition of columbite or tantalite by sulfuric acid yields hydroxides of tantalum and niobium according to the first step of Equation (127). 

Other examples of esterification with trialkyloxonium salts have been reported.7,8 The present procedure offers the advantages that the reactive carboxylate ion is generated in sitv and that a low-boiling, nonaqueous solvent is employed, whereby the experimental procedure is considerably simplified. A related method has been reported which utilizes a hindered amine wdth dimethyl sulfate [Sulfuric acid, dimethyl csterj as the alkylating agent.9 The present procedure is carried out under somewhat milder conditions and avoids the use of highly toxic reagents. 

However, in most cases, relation (48) does not account for results obtained under experimental conditions used in industry, i.e. high reactant concentrations. Othmer carried out a detailed study in this field and suggested second-order reactions for the esterifications of n-butanol with acetic acid245 and monobutyl terephthalate246 catalyzed by sulfuric acid. Since such relations cannot be established in all cases, no reaction order could be found for the esterification of 2,3-butanediol with acetic arid247 in the presence of sulfuric add. Moreover, Othmer s reaction orders were obtained for very concentrated media and in our opinion cannot be connected to a mechanism. In fact, this was not Othmer s objective who established these relations for practical use in industrial esterifications. 

Van Urk s reagent as 4-(dimethylamino)-benzaldehyde - sulfuric acid, but the experimental section incorrectly refers to a solution of 4-(dimethylamino)-benzaldehyde in hydrochloric acid/ethanol as Van Urk s reagent [1]. 

Preparation of Emulsions. The entire aqueous phase was stirred until all solids were dissolved. Sufficient water was withheld from the formulation so small volumes of experimental and control components could be added to emulsion subsamples. Sulfuric acid (1 N) was added to the aqueous phase to decrease the pH to 5.7. The two phases in separate containers were blanketed with nitrogen, sealed, and heated to 75 in an 80 water bath (about 30 minutes). The hot oil phase was stirred slowly and blanketed with nitrogen, then the hot aqueous phase was quickly added while stirring. The emulsion was blanketed with nitrogen and slowly stirred (about 2 hours) in the stoppered container until ambient temperature ( 25 ) was reached. Subsamples of the master batch were removed for the addition of experimental components and stored in 1-oz containers. The containers had been washed with hot tap water, deionized water, and methanol, then dried at 120 . 

P 68] No detailed experimental protocol was given [61, 62,142,143]. Two reactant streams, the solution of the reactant in hexane and concentrated sulfuric acid, were fed separately in a specially designed micro reactor by pumping action. There, a bilayer was formed initially, potentially decomposed to a dispersion, and led to rapid mass transfer between the phases. From this point, temperature was controlled by counter-flow heat exchange between the reaction channel and surrounding heat-transfer channel. The reaction was typically carried out at temperatures from 0 to 50 °C and using residence times of only a few seconds. If needed, a delay loop of... 

The specific activity of the sulfur dioxide was 14, 21, and 13% for the elemental sulfur, hydrogen sulfide, and sulfuric acid treated fruit, respectively (Table III). Thus about the same proportion (within experimental error) of sulfur dioxide is derived from the radioactive elemental sulfur and sulfur acids applied in the treatments. 

Determining the temperature at which ancient sediments were formed entails two successive experimental stages (1) extracting the carbon dioxide from the sediments and (2) determining the relative amounts of the oxygen isotopes in the extracted carbon dioxide. Treating a sediment with a standard acid, such as hydrochloric or sulfuric acid, dissolves the calcium and magnesium carbonates in the sediments and... 

The stereochemistry of electrochemical reduction of acetylenes is highly dependent upon the experimental conditions under which the electrolysis is carried out. Campbell and Young found many years ago that reduction of acetylenes in alcoholic sulfuric acid at a spongy nickel cathode produces cis-olefins in good yields 126>. It is very likely that this reduction involves a mechanism akin to catalytic hydrogenation, since the reduction does not take place at all at cathode substances, such as mercury, which are known to be poor hydrogenation catalysts. The reduction also probably involves the adsorbed acetylene as an intermediate, since olefins are not reduced at all under these conditions and since hydrogen evolution does not occur at the cathode until reduction of the acetylene is complete. Acetylenes may also be reduced to cis olefins in acidic media at a silver-palladium alloy cathode, 27>. 

The end point corresponded to generation of sulfuric acid monohydrate the experimenter subsequently adopted the rules of thumb that oxidative side reactions do not occur while the availability of water is less than this, and that dinitration side-products are a consequence of charging substrate, traditionally but irrationally, to nitration mixture. 

Starting natural graphite from Zavalie deposit in, Ukraine was chemically intercalated in sulfuric acid. Potassium persulphate was used as an oxidizer. Thermal expansion of graphite was performed at 900°C [3], Carbon content in the experimental samples was of about 99.0%. 

In a facile and rapid stereoselective, three-component, one-pot reaction, a series of cis-isoquinolonic acids 132 were synthesized using silica supported sulfuric acid to catalyze the reaction between homophthalic anhydride 133 with different aldehydes 134 and amines 135. This three-component cyclocondensation offers a variety of advantages including high yields, easy experimental work-up, and the use an inexpensive, non-toxic, readily available, and recyclable catalyst <06JHC187>. 

Because sulfuric acid and halogen are very corrosive, selection of the structural materials is an important issue. Screening tests have been carried out using test pieces of commercially available materials at GA [29], JAEA [30,31], etc. As for the gas-phase environment of the H2S04 decomposition step, some refractory alloys that have been used in conventional chemical plants showed good corrosion resistance. Figure 4.13 shows one of the experimental results of Alloys 800 and —600 obtained under gas-phase sulfuric acid decomposition environments at 850°C. Gas compositions in the upstream and downstream... 

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