Ammonium bisulfate concentration

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 ... 

ACH (1) [Acetone CyanHydrin] A process for making methyl methacrylate via this intermediate. Acetone is reacted with hydrogen cyanide to yield the cyanhydrin. This is then converted to methacrylamide, using concentrated sulfuric acid. Methanolysis of this yields methyl methacrylate. Developed by Rohm GmbH Chemische Fabrik, Germany, and ICI, UK used in 11 countries in 1990. Other processes have been developed that avoid the coproduction of large quantities of ammonium bisulfate. See also Alpha (2). 

A mixture of 1 kg. (18.9 moles) of acrylonitrile Caution—volatile toxic material), 6 g. of hydroquinone, 14 g. of copper powder, 648 g. of ice, and 1012 ml. of concentrated sulfuric acid is heated gradually under a reflux condenser on a steam bath. The exothermic reaction is controlled by cautious application of heat, particularly during the first hour. Heating is continued for 48 hours, after which the mixture is cooled and the precipitated ammonium bisulfate is filtered off. The crude acid is distilled by dropping it into a distilling flask loosely packed with fine copper wire and heated to a bath temperature of 250°. The system is maintained under a pressure of about 10 mm, and the distillation receiver is packed in ice. Approximately 1 kg. of clear, colorless distillate is obtained which is shown by analysis to be 86% acrylic acid free of sulfur and nitrogen. 

The problem is operation below the freezing point of ammonium bisulfate. This results in deposition on the catalyst. At the end of this section is a phase-chart showing the deposition temperature of both ammonium sulfate and ammonium bisulfate, as a function of SO3 and ammonia concentrations. 

A series of laboratory experiments was conducted in which galvanized steel samples were exposed to NO2 in air and irradiated propylene/nitrogen oxides/air mixtures in the absence and presence of SO2. Dew was produced periodically on the test panels, and, at the end and/or during the experiments, panels were sprayed with either deionized water or an ammonium bisulfate solution (pH of 3.5). Gas phase concentrations were monitored, and dew and rain rinse samples were analyzed for nitrite, nitrate, sulfite, sulfate, formaldehyde, and zinc. 

This reaction was initially reported by Flood in 1933. It is a synthesis of trialkylsilyl halide involving the treatment of the mixture of di-trialkylsilyl oxide and concentrated sulfuric acid with sodium halide or ammonium halide. The resulting trialkylsilyl halide can be extracted by petroleum ether and then purified via distillation. It was found that when di-trimethylsilyl oxide is mixed with concentrated sulfuric acid, trimethylsilyl sulfate can be isolated as a white crystalline (m.p., Sb-SS C), which forms trimethylsilyl halide when it reacts with ammonium halide. The reaction has been improved by continuous extraction of the reaction mixture with pentane to yield more and purer trialkylsilyl halide and by the addition of ammonium bisulfate to the reaction mixture. ... 

Another separation strategy uses the formation of diammonium succinate, where the ammonium ion is used to control the pH in the fermentation. The diammonium succinate can be concentrated and reacted with a sulfate ion at low pH to yield ammonium sulfate and succinic acid. Succinic acid has very low solubility in aqueous solutions with a pH below 2 and can be crystallized. The succinic acid can be purified with methanol, and the ammonium sulfate is thermally cracked into ammonia and ammonium bisulfate. The ammonia can be fed back into the fermenter, and the ammonium bisulfate can be recycled for use in succinic acid crystallization (Berglund et al. 1999). 

Performance of the air preheater when exposed to high SO3 concentrations and subsequently high concentrations of ammonium sulfate and ammonium bisulfate, and... 

Seasonal variability is shown from the 1979 ERAQS data (Mueller and Watson, 1982) averaged over nine SURE Class I sites in Figure 8 ammonium drops faster than sulfate from summer to winter, resulting in a more acidic composition but lower mass concentrations. In rural areas, the composition is approximately that of ammonium bisulfate, but the aerosol is more nearly neutralized in cities. 

Kjeldahl discovered in 1883 that when agricultural materials were heated with concentrated sulfuric acid, the nitrogen originally present in the organic matter was transformed into ammonium bisulfate. He accomplished the determination of nitrogen by liberation of ammonia through the action of a strong alkali and titration of the ammonia. The chemistry involved can be depicted as follows ... 

The desired chloride is formed when a cold saturated solution of the bisulfate is filtered into an excess of cold concentrated hydrochloric acid or a saturated solution of ammonium chloride. 

The resultant light yellow solution is stirred at -78°C for 12 hr (Note 6). During this time, the color of the solution intensifies considerably. The bright yellow solution is warmed to 0°C in an ice water bath and stirred for 35 min, during which time the color of the solution becomes bright yellow-orange. The reaction is then quenched by the sequential addition of 270 mL of saturated aqueous ammonium chloride and 200 mL of saturated aqueous sodium potassium tartrate. The emulsion is removed from the ice water bath and stirred vigorously for 50 min, by which time adequate phase separation is observed (Note 7). The biphasic mixture is transferred to a 2-L separatory funnel and is extracted with four 175-mL portions of dichloromethane. The combined extracts are washed sequentially with two 500-mL portions of an ice-cooled IM aqueous solution of sodium bisulfate, three 500-mL portions of saturated aqueous sodium bicarbonate and 500 mL of saturated aqueous sodium chloride. The solution is dried over anhydrous sodium sulfate, filtered, and is concentrated under reduced pressure to afford 8.5 g of a yellow oil. 

The different aqueous solutions of bisulfate, ammonium sulfate and sulfuric acid can be utilized as fertilizers after supplementary processing or reconverted to concentrated sulfuric add. To do this, they are incinerated in the presence of methane and air, at... 

The behavior in these two different regimes is depicted in Figure 10.23. The transition occurs at approximately 3.5 pgm3. At very low ammonia concentrations, sulfuric acid and bisulfate constitute the aerosol composition. As ammonia increases ammonium nitrate becomes a significant aerosol constituent. The aerosol liquid water content responds nonlincarly to these changes, reaching a minimum close to the transition between the two regimes. 

Aerosol Na+ and Cl are present in substantial concentrations in regions close to seawater. Sodium and chloride interact with several aerosol components (Table 10.7). A variety of solids can be formed during these reactions including ammonium chloride, sodium nitrate, sodium sulfate, and sodium bisulfate, while HCl(g) may be released to the gas phase. 

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