Sulfuric acid reactant

A suitable microreactor system corresponding to the above mentioned requirements was developed by Worz et al. [89]. Their installation consisted of 32 stainless steel channels of 900 X 60 pm size separated by cooling channels (Figure 7.24). Reactant and the acid were mixed extremely fast in these microchannels and cooled simultaneously. As the product is sensitive for consecutive reactions, it is obvious that the absence of backmixing increases the product yield. At a temperature of 20 C, a maximum yield of 90-95% could be achieved with a residence time of 30 s. The reaction is quenched by diluting the concentrated sulfuric acid-reactant mixture with water. The dilution of concentrated sulfuric acid has an even higher exothermicity and must carried... 

The ratio of reactants had to be controlled very closely to suppress these impurities. Recovery of the acrylamide product from the acid process was the most expensive and difficult part of the process. Large scale production depended on two different methods. If soHd crystalline monomer was desired, the acrylamide sulfate was neutralized with ammonia to yield ammonium sulfate. The acrylamide crystallized on cooling, leaving ammonium sulfate, which had to be disposed of in some way. The second method of purification involved ion exclusion (68), which utilized a sulfonic acid ion-exchange resin and produced a dilute solution of acrylamide in water. A dilute sulfuric acid waste stream was again produced, and, in either case, the waste stream represented a... 

Triple (Concentrated) Superphosphate. The first important use of phosphoric acid in fertilizer processing was in the production of triple superphosphate (TSP), sometimes called concentrated superphosphate. Basically, the production process for this material is the same as that for normal superphosphate, except that the reactants are phosphate rock and phosphoric acid instead of phosphate rock and sulfuric acid. The phosphoric acid, like sulfuric acid, solubilizes the rock and, in addition, contributes its own content of soluble phosphoms. The result is triple superphosphate of 45—47% P2 s content as compared to 16—20% P2 5 normal superphosphate. Although triple superphosphate has been known almost as long as normal superphosphate, it did not reach commercial importance until the late 1940s, when commercial supply of acid became available. 

In a typical isothermal process, 70% hydrogen peroxide is added to 98% sulfuric acid, and subjected to rapid stirring and efficient cooling, so that the temperature does not rise to above 15°C. If equimolar quantities of reactants are used, the product contains 42% H2SO and 10% H2O2. Although the reaction may seem simple, many of its features are critically important and it should only be attempted foUowiag advice from speciaUsts. 

Propylene, butylenes, or amylenes are combiaed with isobutane ia the presence of an acid catalyst, eg, sulfuric acid or hydrofluoric acid, at low temperatures (1—40°C) and pressures, 102—1035 kPa (1—10 atm). Sulfuric acid or hydrogen fluoride are the catalysts used commercially ia refineries. The acid is pumped through the reactor and forms an emulsion with reactants, and the emulsion is maintained at 50% acid. The rate of deactivation varies with the feed and isobutane charge rate. Butene feeds cause less acid consumption than the propylene feeds. 

There are explosion hazards with phthahc anhydride, both as a dust or vapor in air and as a reactant. Table 11 presents explosion hazards resulting from phthahc anhydride dust or vapor (40,41). Preventative safeguards in handling sohd phthahc anhydride have been reported (15). Water, carbon dioxide, dry chemical, or foam may be used to extinguish the burning anhydride. Mixtures of phthahc anhydride with copper oxide, sodium nitrite, or nitric acid plus sulfuric acid above 80°C explode or react violently (39). 

The principal reactions are reversible and a mixture of products and reactants is found in the cmde sulfate. High propylene pressure, high sulfuric acid concentration, and low temperature shift the reaction toward diisopropyl sulfate. However, the reaction rate slows as products are formed, and practical reactors operate by using excess sulfuric acid. As the water content in the sulfuric acid feed is increased, more of the hydrolysis reaction (Step 2) occurs in the main reactor. At water concentrations near 20%, diisopropyl sulfate is not found in the reaction mixture. However, efforts to separate the isopropyl alcohol from the sulfuric acid suggest that it may be partially present in an ionic form (56,57). 

The reaction between urea and Aiming sulfuric acid is rapid and exothermic. It may proceed with violent boiling unless the reaction temperature is controlled. The reactants are strongly acidic. Therefore, operators should wear suitable protective gear to guard against chemical hazard. Special stainless steel, mbber lining, fiber-reinforced plastics, and polyvinyl chloride and carbon equipment are used. 

Hydrolysis of solutions of Ti(IV) salts leads to precipitation of a hydrated titanium dioxide. The composition and properties of this product depend critically on the precipitation conditions, including the reactant concentration, temperature, pH, and choice of the salt (46—49). At room temperature, a voluminous and gelatinous precipitate forms. This has been referred to as orthotitanic acid [20338-08-3] and has been represented by the nominal formula Ti02 2H20 (Ti(OH). The gelatinous precipitate either redissolves or peptizes to a colloidal suspension ia dilute hydrochloric or nitric acids. If the suspension is boiled, or if precipitation is from hot solutions, a less-hydrated oxide forms. This has been referred to as metatitanic acid [12026-28-7] nominal formula Ti02 H2O (TiO(OH)2). The latter precipitate is more difficult to dissolve ia acid and is only soluble ia concentrated sulfuric acid or hydrofluoric acid. 

In some processes the reactant bases are too weak to be protonated significantly except in the presence of very strong acids such as fuming sulfuric acid or a mixture of concentrated sulfuric and nitric acids, ie, mixed acid. Nitration of toluene, for example, requires such solutions two Hquid phases are present in the reactor. 

In a study of the kinetics of the reaction of 1-butanol with acetic acid at 0—120°C, an empirical equation was developed that permits estimation of the value of the rate constant with a deviation of 15.3% from the molar ratio of reactants, catalyst concentration, and temperature (30). This study was conducted usiag sulfuric acid as catalyst with a mole ratio of 1-butanol to acetic acid of 3 19.6, and a catalyst concentration of 0—0.14 wt %. 

Yourfacility receives toluene and naphthalene (both listed toxic chemicals) from an off-site location. You react the toluene with air to form benzoic acid and react the naphthalene with sulfuric acid, which forms phthalic acid and also produces sulfur dioxide fumes. Your facility processes toluene and naphthalene. Both are used as reactants to produce benzoic acid and phthalic acid, chemicals not on the section 313 list. 

This ease with which we can control and vary the concentrations of H+(aq) and OH (aq) would be only a curiosity but for one fact. The ions H+(aq) and OH (aq) take part in many important reactions that occur in aqueous solution. Thus, if H+(aq) is a reactant or a product in a reaction, the variation of the concentration of hydrogen ion by a factor of 1012 can have an enormous effect. At equilibrium such a change causes reaction to occur, altering the concentrations of all of the other reactants and products until the equilibrium law relation again equals the equilibrium constant. Furthermore, there are many reactions for which either the hydrogen ion or the hydroxide ion is a catalyst. An example was discussed in Chapter 8, the catalysis of the decomposition of formic acid by sulfuric acid. Formic acid is reasonably stable until the hydrogen ion concentration is raised, then the rate of the decomposition reaction becomes very rapid. 

Reaction (25) between methanol and acetic acid is slow, but it can be speeded up greatly if a catalyst is added. For example, addition of a strong acid such as hydrochloric acid or sulfuric acid will speed up the reaction by catalysis. As mentioned in Section 9-1.4, the catalyst does not alter the equilibrium state (that is, the concentrations of the reactants at equilibrium), but only permits equilibrium to be attained more rapidly. 

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. 

Forms azeotropic mixts with butyl ale, acetic acid, heptane, toluene, nitroethane, perchioro-ethylene, w, etc. Prepn is by reacting propyl ale with coned nitric acid (d 1.41g/cc) dissolved in ethylacetate at 20°, followed by distn of the product. NPN can also be preod bv reacting a continuous stream of propyl ale below the surface of stirred mixed acid (20% nitric acid, 68% sulfuric acid and 12% w by wt) in a cooled (0—5°) open stainless steel vessel. Addnl mixed acid is also simultaneously introduced at about a third of the depth of the liq. An overflow pipe maintains a constant reactant level and the effluent prod is sepd, washed with 10% aq Na carbonate soln and dried by passage thru a Filtrol packed tower. Contact time of reactants can vary from 0.6 to 15 mins using about 50% isopropanol at 0° to yield 66.5% NPN (Ref 3b)... 

In 1969 a serious explosion took place in Basle when 287 kg (1.3 kmol) of 2-chloro-4,6-dinitroaniline was diazotized in 384 kg 40% nitrosylsulfuric acid. The temperature was increased from 30 °C to 50 °C and kept at that level. Shortly afterwards the explosion occurred three workers were killed and 31 injured, some seriously. The reaction had been carried out twice before in the same way without difficulty. Detailed investigations (Bersier et al., 1971) with the help of differential scanning calorimetry showed that, at the high concentration of that batch, a strongly exothermic reaction (1500 kJ/kg) starts at about 77 °C. In contrast, when the reactants were diluted with 96% sulfuric acid to twice the volume, the reaction was found to begin at 146 °C, generating only 200 kJ/kg. 

This is a chemical reaction. The fact that iron reacts when it comes into contact with sulfuric acid is a chemical property of iron. Conversely, the ability of sulfuric acid to affect iron is a chemical property of sulfuric acid. The sulfuric acid and iron are called reactants in the above equation, and the iron sulfate and hydrogen are the products of the reaction. 

To evaluate the heat exchange/productivity performances of the device and its environment, an acid-base neutralization involving sulfuric acid and soda has been performed. It is an instantaneous and exothermic reaction with AH = —92.4 kj moP (NaOH). Each experiment is characterized by the initial concentration of the reactants (from 10 to 30% in mass of soda and from 5 to 12% in mass of sulfuric acid). These concentrations are varied in order to evaluate the behavior of the reactor with respect to different amounts of heat generated (from 0.4 to 1.3 kW). Each run is performed with a variable utility flow rate (from 1 to 3 m h ). 

By reaction of sulfuric acid and benzal chloride benzaldehyde is generated. Both reactants are rather viscous and immiscible leading to the above mentioned reaction problems [46]. Due to temperature increase and too long reaction times, side reactions such as the oxidation to benzoic acid occur. 

The reactants and the product were not disclosed in the open literature as the industrial process is proprietary [61, 62,127,142,143]. The reactant is dissolved in hexane and the reaction is catalyzed by concentrated sulfuric acid which is present in quantitative amounts. Thus, the reaction is carried out as a liquid/liquid process. A reaction scheme is given in [61, 62]. The reactant quickly forms an intermediate which again quickly reacts to give the product. Thermally induced side reactions occur. 

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... 

Reactions which under existing conditions cannot be inverted because of lack of reactants. Thus, metallic zinc readily dissolves anodicaUy in sulfuric acid solution [reaction (1.21) from the right to the left], but when this solution contains no zinc salt, the reverse reaction in which zinc is deposited cathodicaUy cannot occur. 

In a chemical equation, like the one for the reaction between sulfuric acid and potassium hydroxide, the reactants (the substances being mixed together) are always written on the left-hand side of the equation. The products (the substances made when the reactants react with each other) are placed on the right-hand side of the equation. Atoms cannot be made or destroyed in a chemical reaction, only rearranged. This is called the law of conservation of matter. Therefore, there must always be the same number of atoms of each element on the reactant side of the equation as there are on the product side. 

To build the balanced chemical equation that shows the chemical reaction between sulfuric acid and potassium hydroxide, start off by writing the reactants on the left-hand side of the equation ... 

The extra hydrogen atom on the reactant side of the equation cannot just disappear. Likewise, there cannot be more potassium atoms on the right side of the equation than on the left side. Therefore, sulfuric acid and potassium hydroxide must not react in a 1 1 ratio. Instead, for every molecule of sulfuric acid that reacts, there must be two molecules of potassium hydroxide ... 

Now there are four hydrogen atoms on the reactant side (two in sulfuric acid and one in each of the two molecules of potassium hydroxide) and four hydrogen atoms on the product side (two in each of the two molecules of water). All of the other atoms have equal numbers on each side as well. Now the equation conforms to the law of conservation of matter, and it is a balanced chemical equation. 

Fixed Bed Reactors. In its most basic form, a fixed bed reactor consists of a cylindrical tube filled with catalyst pellets. Reactants flow through the catalyst bed and are converted into products. Fixed bed reactors are often referred to as packed bed reactors. They may be regarded as the workhorse of the chemical industry with respect to the number of reactors employed and the economic value of the materials produced. Ammonia synthesis, sulfuric acid production (by oxidation of S02 to S03), and nitric acid production (by ammonia oxidation) are only a few of the extremely high tonnage processes that make extensive use of various forms of packed bed reactors. 

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