Salts sulfates

Sulfate salts are sometimes added to batteries to depress the formation of large lead sulfate crystals that are difficult to recharge. Failure by sulfation is common when the battery is deeply discharged or left on open-circuit in the discharged state. Because crystals of barium sulfate and strontium sulfate are isomorphous with lead sulfate and are relatively insoluble, they can nucleate the lead sulfate crystals and thus reduce their size. 

The addition of sulfates to the positive plate was evaluated by Lorenz (as described in Ref. 58). Results showed that 0.5wt.% barium sulfate or strontium sulfate added to the positive active-material reduced the cycle-life from 100 cycles without the additive to 30-50 cycles with the additive under the same conditions. The end-of-life was taken as a 40% decline in the initial capacity. Lorenz further reported that calcium sulfate is not isomorphous with lead sulfate and therefore has no effect on battery life. (Note, calcium sulfate also does not act as an inorganic expander for negative plates.) 

The cycle-life of cells discharged at the C/5 rate to 0.7 V was found to decrease when 0.3 or 3wt.% BaS04 was added to the positive plate [59]. Compared with an undoped plate, the addition of 3 wt.% BaS04 decreased the cycle-life by a factor of 

Sodium sulfate is not isomorphous with lead sulfate and is more soluble. The solubility of lead sulfate in sulfuric acid containing sodium sulfate is given in Table 4.6 for acid concentrations from 0 to 10 wt.% [60,61]. When dissolved in the 

In the early 1950s, the United States National Bureau of Standards evaluated a battery electrolyte additive which contained sodium sulfate and magnesium sulfate. The manufacturer s claim was that the additive could restore the performance of 

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The amide group is readily hydrolyzed to acrylic acid, and this reaction is kinetically faster in base than in acid solutions (5,32,33). However, hydrolysis of N-alkyl derivatives proceeds at slower rates. The presence of an electron-with-drawing group on nitrogen not only facilitates hydrolysis but also affects the polymerization behavior of these derivatives (34,35). With concentrated sulfuric acid, acrylamide forms acrylamide sulfate salt, the intermediate of the former sulfuric acid process for producing acrylamide commercially. Further reaction of the salt with alcohols produces acrylate esters (5). In strongly alkaline anhydrous solutions a potassium salt can be formed by reaction with potassium / /-butoxide in tert-huty alcohol at room temperature (36). 

The current routes to acrylamide are based on the hydration of inexpensive and readily available acrylonitrile [107-13-1] (C3H3N, 2-propenenittile, vinyl cyanide, VCN, or cyanoethene) (see Acrylonitrile). For many years the principal process for making acrylamide was a reaction of acrylonitrile with H2SO4 H2O followed by separation of the product from its sulfate salt using a base neutralization or an ion exclusion column (68). 

Hydrazine [302-01-2] (diamide), N2H4, a colorless liquid having an ammoniacal odor, is the simplest diamine and unique in its class because of the N—N bond. It was first prepared in 1887 by Curtius as the sulfate salt from diazoacetic ester. Thiele (1893) suggested that the oxidation of ammonia (qv) with hypochlorite should yield hydrazine and in 1906 Raschig demonstrated this process, variations of which constitute the chief commercial methods of manufacture in the 1990s. 

After sulfuric acid work-up (accompanied by the formation of sodium sulfate), the resorcinol is extracted and isolated in a 94% yield based on y -benzenedisulfonic acid [98-48-6]. In addition to the technical complexity that goes along with the manipulation of soHds at high temperature, this process produces large amounts of salts (sulfite and sulfate salts) which economically as well as environmentally are not always desired. 

Cmde diketene obtained from the dimeriza tion of ketene is dark brown and contains up to 10% higher ketene oligomers but can be used without further purification. In the cmde form, however, diketene has only limited stabHity. Therefore, especiaHy if it has to be stored for some time, the cmde diketene is distiHed to > 99.5% purity (124). The tarry distiHation residue, containing trike ten e (5) and other oligomers, tends to undergo violent Spontaneous decomposition and is neutralized immediately with water or a low alcohol. Ultrapure diketene (99.99%) can be obtained by crystallization (125,126). Diketene can be stabHized to some extent with agents such as alcohols and even smaH quantities of water [7732-18-5] (127), phenols, boron oxides, sulfur [7704-34-9] (128) and sulfate salts, eg, anhydrous copper sulfate [7758-98-7]. 

The salt ia this case is tetrakis(hydroxymethyl)phosphonium chloride [124-64-1]. The corresponding sulfate salt [55566-30-8] is also produced commercially as are urea-containing formulations of both salts. The latter formulations are actually used to flame retard the textiles (see Flame retardants FOR textiles). 

Several types of chemical processes are used to produce potassium sulfate. The traditional Mannheim process is used in countries that produce KCl but lack a natural source of sulfate salts for converting the KCl to K2SO4. In this process, KCl reacts with sulfuric acid to yield K2SO4 and HCl as a co-product. 

Kieserite is not present in U.S. potassium salt deposits in commercial quantities. Langbeinite is the predominant U.S. magnesium sulfate salt. The latter, a raw material for the production of potassium sulfate in New Mexico, reacts directiy with potassium chloride ... 

Ritter Reaction (Method 4). A small but important class of amines are manufactured by the Ritter reaction. These are the amines in which the nitrogen atom is adjacent to a tertiary alkyl group. In the Ritter reaction a substituted olefin such as isobutylene reacts with hydrogen cyanide under acidic conditions (12). The resulting formamide is then hydroly2ed to the parent primary amine. Typically sulfuric acid is used in this transformation of an olefin to an amine. Stoichiometric quantities of sulfate salts are produced along with the desired amine. 

In the reaction of arulinium sulfate [542-16-5] with fuming sulfuric acid, the major products are m- and -aminoben2enesulfonic acid with less than 2% of the ortho isomer. With excess concentrated sulfuric acid (96.8—99.9%) at 60—100°C, the sulfate salt gives mainly the ortho and para isomers of the sulfonic acid (42). 

Its chief use is as a component in photographic developers. Because the free compound is unstable in air and light, it is usually marketed as the sulfate salt [55-55-0] Metol, mp 260°C (dec.). It also finds appHcation as an intermediate for fur and hair dyes and, under certain circumstances, as a corrosion inhibitor for steel. Prolonged exposure to 4-(/V-methy1amino)pheno1 has been associated with the development of dermatitis and allergies. 

Organic Reactions. Primary alcohols react with sulfamic acid to form alkyl ammonium sulfate salts (21—23) ... 

Vanadium Sulfates. Sulfate solutions derived from sulfuric acid leaching of vanadium ores are industrially important in the recovery of vanadium from its raw materials. Vanadium in quadrivalent form may be solvent-extracted from leach solutions as the oxycation complex (VO) ". Alternatively, the vanadium can be oxidized to the pentavalent form and solvent-extracted as an oxyanion, eg, (V O ) . Pentavalent vanadium does not form simple sulfate salts. 

Fig. 4. (a) Yam resistance in n-cm vs amount of antistatic agent on the yam. The agent is the ethyl sulfate salt of an amine, (b) Resistance vs amount of nonionic, hygroscopic agent on the yam. Dotted lines are calculated from the specific resistance of the dry bulk solution soHd lines are experimental yam... 

Zinc chloride is a Lewis acid catalyst that promotes cellulose esterification. However, because of the large quantities required, this type of catalyst would be uneconomical for commercial use. Other compounds such as titanium alkoxides, eg, tetrabutoxytitanium (80), sulfate salts containing cadmium, aluminum, and ammonium ions (81), sulfamic acid, and ammonium sulfate (82) have been reported as catalysts for cellulose acetate production. In general, they require reaction temperatures above 50°C for complete esterification. Relatively small amounts (<0.5%) of sulfuric acid combined with phosphoric acid (83), sulfonic acids, eg, methanesulfonic, or alkyl phosphites (84) have been reported as good acetylation catalysts, especially at reaction temperatures above 90°C. 

Pyrolysis. Pyrolysis of 1,2-dichloroethane in the temperature range of 340—515°C gives vinyl chloride, hydrogen chloride, and traces of acetylene (1,18) and 2-chlorobutadiene. Reaction rate is accelerated by chlorine (19), bromine, bromotrichloromethane, carbon tetrachloride (20), and other free-radical generators. Catalytic dehydrochlorination of 1,2-dichloroethane on activated alumina (3), metal carbonate, and sulfate salts (5) has been reported, and lasers have been used to initiate the cracking reaction, although not at a low enough temperature to show economic benefits. 

Bake sulfonation is an important variant of the normal sulfonation procedure. The reaction is restricted to aromatic amines, the sulfate salts of which ate prepared and heated (dry) at a temperature of approximately 200°C in vacuo. The sulfonic acid group migrates to the ortho or para positions of the amine to give a mixture of orthanilic acid [88-21-1] and sulfanilic acid [121 -57-3] respectively. This tendency is also apparent in polynuclear systems so that 1-naphthylamine gives 1-naphthy1amine-4-su1fonic acid. 

Nickel sulfamate is more soluble than the sulfate salt, and baths can be operated using higher nickel concentrations and higher currents. Sulfamate baths have been found to have superior microthrowing power, the abiUty to deposit in small cracks or crevices. Using one nickel salt, only a hydrometer and pH paper are needed to control the bath. A small amount of chloride salt was added as a proprietary. Highly purified nickel sulfamate concentrates are commercially available that can be used to make up new plating baths without further purification. 

The precious-metal platinum catalysts were primarily developed in the 1960s for operation at temperatures between about 200 and 300°C (1,38,44). However, because of sensitivity to poisons, these catalysts are unsuitable for many combustion apphcations. Variations in sulfur levels of as Httle as 0.4 ppm can shift the catalyst required temperature window completely out of a system s operating temperature range (44). Additionally, operation withHquid fuels is further compHcated by the potential for deposition of ammonium sulfate salts within the pores of the catalyst (44). These low temperature catalysts exhibit NO conversion that rises with increasing temperature, then rapidly drops off, as oxidation of ammonia to nitrogen oxides begins to dominate the reaction (see Fig. 7). 

Sulphate SO4 Increased solid content Combines with Ca to form calcium sulfate salt Distillation Demineralization... 

Sulfate ions have reactions similar to those of chloride. They are corrosion-causative agents (similar to oxygen and hydrogen) of the various types of concentration cell corrosion. In addition, they also are depassivation agents and may greatly accelerate the risk of stress corrosion mechanisms. Saline corrosion pits resulting from high concentrations of chloride and sulfate salts also may be associated with low pH corrosion because hydrochloric acid and sulfuric acid can form within the pit, under deposits. 

Acid addition is commonly used to convert bicarbonates into the more soluble sulfate salts to reduce the alkalinity of the RO RW, which in turn modifies the brine reject water LSI. Sometimes it is required to maintain the pH level within membrane limits. Additionally, it may be used in conjunction with a reduced dosage of antiscalent chemical to reduce the overall chemical treatment costs. 

The alcohol sulfate salts of monovalent metals, such as sodium and potassium, crystallize as anhydrous salts from aqueous solutions, whereas salts of bivalent alkaline earth metals form hydrates with 1 mol of water less than that of the equivalent inorganic sulfate [68]. 

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