Ammonium bisulfate

Ammonium sulfate [7783-20-2], (NH 2 U4, is a white, soluble, crystalline salt having a formula wt of 132.14. The crystals have a rhombic stmcture d is 1.769. An important factor in the crystallization of ammonium sulfate is the sensitivity of its crystal habit and size to the presence of other components in the crystallizing solution. If heated in a closed system ammonium sulfate melts at 513 2° C (14) if heated in an open system, the salt begins to decompose at 100°C, giving ammonia and ammonium bisulfate [7803-63-6], NH HSO, which melts at 146.9°C. Above 300°C, decomposition becomes more extensive giving sulfur dioxide, sulfur trioxide, water, and nitrogen, in addition to ammonia. 

Methyl Methacrylate and Methacryhc Acid. The traditional production of methyl methacrylate [80-62-6] and methacryhc acid [79-41-4] involves the reaction of acetone with HCN and subsequent conversion to methyl ester and by-product ammonium bisulfate. Older plants in the United States with capacities in the range of 380,000 t/yr stUl use this process. 

The handling of toxic materials and disposal of ammonium bisulfate have led to the development of alternative methods to produce this acid and the methyl ester. There are two technologies for production from isobutylene now available ammoxidation to methyl methacrylate (the Sohio process), which is then solvolyzed, similar to acetone cyanohydrin, to methyl methacrylate and direct oxidation of isobutylene in two stages via methacrolein [78-85-3] to methacryhc acid, which is then esterified (125). Since direct oxidation avoids the need for HCN and NH, and thus toxic wastes, all new plants have elected to use this technology. Two plants, Oxirane and Rohm and Haas (126), came on-stream in the early 1980s. The Oxirane plant uses the coproduct tert-huty alcohol direcdy rather than dehydrating it first to isobutylene (see Methacrylic acid). 

The oxime is converted to caprolactam by Beckmann rearrangement neutralization with ammonia gives ca 1.8 kg ammonium sulfate per kilogram of caprolactam. Purification is by vacuum distillation. A no-sulfate, extraction process has been described, but incineration of the ammonium bisulfate recovers only sulfur values and it is not practiced commercially (14). 

Acetaldehyde Cyanohydrin. This cyanohydrin, commonly known as lactonitnle, is soluble in water and alcohol, but insoluble in diethyl ether and carbon disulfide. Lactonitnle is used chiefly to manufacture lactic acid and its derivatives, primarily ethyl lactate. Lactonitnle [78-97-7] is manufactured from equimolar amounts of acetaldehyde and hydrogen cyanide containing 1.5% of 20% NaOH at —10 20 ° C. The product is stabili2ed with sulfuric acid (28). Sulfuric acid hydroly2es the nitrile to give a mixture of lactic acid [598-82-3] and ammonium bisulfate. 

This mixture can be purified by adding methanol to form methyl lactate [547-64-8] which is separated from the ammonium bisulfate. The methyl lactate is distilled, then hydroly2ed back to the aqueous acid. Removal of most of the water yields 90% lactic acid (29). 

The methaciylamide sulfate is esteiified with methanol to give methyl methacrylate and ammonium bisulfate [7802-63-6J as a by-product. 

Conversion of acetone cyanohydrin to methyl methacrylate produces a large amount of ammonium bisulfate by-product which lacks ready marketabihty and is usually converted to sulfuric acid for reuse in the conversion of acetone cyanohydrin to methacrylates. The nitrogen values of the... 

The formation of ammonium bisulfate is strongly temperature dependent. Formation is favored at the lower temperatures. The temperature at which ammonium bisulfate is not formed depends strongly on the SO concentration in the exhaust gas. The temperature needed to minimize bisulfate formation has been reported to increase by about I5°C (around about 350°C) when the SO concentration increases from 5 to 15 ppm (23). The formation of the bisulfate is reversible, ie, if the temperature is raised to 20°C above the minimum temperature, the reaction is shifted to result in the decomposition of the bisulfate formed. When chlorides are present, ammonium chlorides can be formed ... 

When sulfuric acid is present, ammonium bisulfate can be formed ... 

Other problems that can be associated with the high dust plant can include alkaH deterioration from sodium or potassium in the stack gas deposition on the bed, calcium deposition, when calcium in the flue gas reacts with sulfur trioxide, or formation and deposition of ammonium bisulfate. In addition, plugging of the air preheater as weU as contamination of flyash and EGD wastewater discharges by ammonia are avoided if the SCR system is located after the FGD (23). 

Ammonium bisulfate (ammonium hydrogen sulfate) [7803-63-6] M 115.1°, m -147°, d 1.79, pK 1.96 (HS04 ). Crystd from water at room temperature (ImL/g) by adding EtOH and cooling. 

Oxides of sulfur Sulfur dioxide SO2 Sulfur trioxide SO3 Sulfuric acid H2SO4 Ammonium bisulfate (NH))HS04 Ammonium sulfate (NH4)2S04... 

Sulfuric acid (H1SO4) and ammonium bisulfate (NH4HSO4) contribute importantly to ambient acid aerosols, particularly in geographic locations where sulfur-rich coal is used for power plant fuel, such as the eastern United States.Studies on animals and human subjects have shown that H2SO4 and NH4HSO4 alter mucociliary transport in a dose-dependent fashion and... 

Ammonium acetate Ammonium adipate Ammonium benzoate Ammonium bicarbonate Ammonium biflluoride Ammonium binoxalate Ammonium bisulfate Ammonium bitartrate Ammonium tetraborate Ammonium bromide Ammonium carbonate Ammonium chloride Ammonium citrate Ammonium diclnomate Ammonium fluoride Ammonium fluorosilicate Ammonium gluconate Ammonium iodide Ammonium molybdate Ammonium nitrate Ammonium oxalate Ammonium perchlorate Ammonium picrate Ammonium polysulfide Ammonium salicylate Ammonium stearate Ammonium sulfate Ammonium sulfide (hydrosulfide) Ammonium tartrate Ammonium tliiocyanate Ammonium thiosulfate... 

The epoxidation method developed by Noyori was subsequently applied to the direct formation of dicarboxylic acids from olefins [55], Cyclohexene was oxidized to adipic acid in 93% yield with the tungstate/ammonium bisulfate system and 4 equivalents of hydrogen peroxide. The selectivity problem associated with the Noyori method was circumvented to a certain degree by the improvements introduced by Jacobs and coworkers [56]. Additional amounts of (aminomethyl)phos-phonic acid and Na2W04 were introduced into the standard catalytic mixture, and the pH of the reaction media was adjusted to 4.2-5 with aqueous NaOH. These changes allowed for the formation of epoxides from ot-pinene, 1 -phenyl- 1-cyclohex-ene, and indene, with high levels of conversion and good selectivity (Scheme 6.3). 

The organic phase was evaporated and the residue dissolved in chloroform. A portion of the chloroform solution was spotted on silica gel plates which were then developed in chloroform methanol ammonia (89 10 1). After development, the plate was air dried and sprayed with a 2M aqueous solution of ammonium bisulfate. After the plate was air dried for 1 hour, the fluorescent spot representing triprolidine was quantitated with a spectrodensitometer in the reflectance mode with 300 nm excitation and emission above 405 nm. With... 

Ammonium acetates, 2 711-712 Ammonium alum calcination, 2 395 neutralization, 2 430 Ammonium benzoate, 3 634 Ammonium bicarbonate, 2 712-713 Ammonium bifluoride, 2 717-718 Ammonium bisulfate formation, 10 98 Ammonium bromide, 2 714... 

The process consumes the sulfuric acid and produces a waste. product, ammonium bisulfate, so it is expensive. So when propylene oxidation technology was developed, it became the preferred route. 

Several alternate routes to MMA eliminate ammonium bisulfate byproduct—really a coproduct since its 1.5 tons for every 10 tons of MMA produced. They also do not involve HCN, always a safety problem in the plants and sometimes an unreliable market. Although these routes are more efficient and economical, American producers have stuck to the acetone cyanohydrin route. The plants are fully amortized and by staying with the old technology, producers can avoid the large capital investments associated with a new plant. 

Aqueous solutions of ammonium sulfate and ammonium bisulfate were deposited on Fluoropore filters, placed in the direct insertion probe, and analyzed in the chemical ionization mode (H2O reagent) gas. The samples were heated from 100°C to 330 C at 15 C/minute. No sample ions were observed under these anlaysis conditions, even when several micrograms of ammonium salts were analyzed. The thermal decomposition of ammonium salts of sulfate has been the subject of many studies. (29,30) Some pathways include sulfuric acid production at one stage of the decomposition while others suggest ammonia, SO2 and SO3 are the products. None of these accurately simulate the conditions (temperature, pressure, gas flow) present in our chemical ionization source. However, no sulfuric acid ions (H3SO4+, etc.) were ob-served... 

Methane chemical ionization spectra of ammonium sulfate and ammonium bisulfate are similar to that of sulfuric acid. The elution profile, however, is quite different, as can be seen from Figure 7. If the salts were deposited on the filter in aerosol form, the shape of the elution profile was somewhat narrower and began at a slightly lower temperature compared to the profile obtained when the salt was deposited in aqueous solution from a syringe. In no case, however, did the elution profile of any of the salts tested overlap the profile for sulfuric acid. 

Fouling Salt formation can build-up on the catalyst surface effectively limiting accessibility. Ammonium bisulfate can form at low temperatures. This foulant can be removed by increasing temperature and is considered a temporary poison. 

Oxidation of SO2 to SO3 Ammonia oxidation to NO Sulfuric acid formation Ammonium bisulfate formation ... 

The oxidation of SO2 to SO3 is undesirable for several reasons. SO3 will result in a blue plume off the stack and increase opacity. SO3 will also continue to react to form sulfuric acid and ammonium bisulfate. Sulfuric acid will corrode downstream equipment like economizers and ductwork as well as leave the stack as an acid mist. SO3 will also reactant with NH3 to form ammonium bisulfate salt (ABS), which is corrosive and tacky. ABS will sublime from a gas to its solid form at and below its dew point. 

Ammonia slip on large units like an FCCU translates to wasted chemical expense with no benefit to the refiner. Excess ammonia in a high temperature SCR will oxidize to create NO, which is counter to the intended purpose of the unit. Excess ammonia in a low temperature SCR will tend to form ammonium bisulfate (ABS) per Figure 17.9. 

Ammonium bisulfate is a corrosive salt that sublimes from a vapor to a solid at temperatures below its dew point. The salt will foul downstream equipment resulting in higher pressure drops across economizers and preheaters. Ammonium bisulfate can be returned to its vapor state if the temperature is increased above its ABS dew point. 

Ammonium sulfate decomposes upon heating at 100°C in an open system, forming ammonium bisulfate, NH4HSO4. As a salt of a strong acid and weak base, its solution is acidic pH of 0. IM solution is 5.5. 

RH (e.g., Oatis et al., 1998). In addition, there is evidence that new metastable solid states can form in these droplets (Tang et al., 1995). Similar studies of ammonium bisulfate, NH4HS04, have been carried out over a range of temperatures and relative humidities relevant to the atmosphere, and its phase diagram, including metastable states and a crystalline hydrate phase at low temperatures has been reported (Imre et al, 1997). 

In cases in which the space charge across the electrical field was insufficiently intense for proper charge buildup, it was found that ammonia injection improved the capturability of the fly ash (14)- Other studies confirmed the applicability of sulfuric acid, ammonium sulfate and ammonium bisulfate as useful conditioners (15). 

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