Zinc sulfate, decomposition

A preferable, three-step, procedure for preparing anhydrous bis(2,4-pentanedionato)zinc, m.p. 127°, in good yields involves (1) the preparation of bis(2,4-pentanedionato)zinc hydrate from zinc sulfate heptahydrate and 2,4-pentanedione in aqueous solution in the absence of heat, (2) conversion of the bis(2,4-pentanedionato)zinc hydrate into a bis (2,4-pentanedionato) zinc-methanol adduct, and (3) decomposition of the methanol adduct. 

To a solution of 100 g. (1 mol) of 2,4-pentanedione and 40 g. (1 mol) of sodium hydroxide in 500 ml. of water is slowly added with stirring a solution of 144 g. (0.5 mol) of zinc sulfate heptahydrate in 500 ml. of water. After the suspension has stood for one hour, the white precipitate is filtered, washed with water, and dried, to give 122 g. (87%) of rather pure bis(2,4-pentanedionato)zinc hydrate with m.p. 138°. The crude product is dissolved in 11. of hot ethyl acetate, to which 50 ml. of 2,4-pentanedione has been added. The solution is filtered hot in order to remove a small amount of high-melting decomposition products. From the cooled solution, 90 g. (64%) of bis(2,4-pentanedionato) zinc hydrate is obtained as needles, m.p. 138 to 140°. 

SAFETY PROFILE Human poison by an unspecified route. Poison experimentally by subcutaneous, intravenous, and intraperitoneal routes. Moderately toxic by ingestion. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of SOx and ZnO. See also ZINC SULFATE. 

The results of our evaluations for the other hybrid cycles are summarized in Table 3. The advantages of the Cu-Cl cycle are its low maximum temperature requirement and its relatively high efficiencies. The Level 1 and 2 efficiencies exceed 40% (LHV). All reactions in this cycle have been proven [1, 9, 10]. The Mg-Cl cycle has a low maximum temperature requirement but comparatively low Level 1 and 2 efficiencies. The chemistry for the thermal reactions has not been demonstrated. The low maximum temperatures, 550 and 600°C, respectively, for the two chloride cycles provide more flexibility in coupling them with heat sources other than the VHTGR. The advantages of the metal sulfate cycles are their lower corrosivity and the common high temperature decomposition reaction with the sulfur cycles. Of the two metal sulfate cycles, the copper sulfate cycle appears more promising because the copper sulfate cycle requires somewhat lower temperatures than the zinc sulfate cycle. The copper sulfate cycle has also been demonstrated with recycled materials, but no experimental work has been reported for the zinc sulfate cycle [1]. 

Li and coworkers [50] studied the zinc hydroxide carbonate precursor, Zii4C03(0H)6-H20, synthesized from zinc sulfate using ammonium carbonate as a precipitating agent. TG), DSC, transmission electronic microscopy (TEM), infiared spectroscopy (IR) and XRD were used to characterize die precursor and the decomposition product, while the non-isothermal kinetics of the thermal decomposition of zinc hydroxide carbonate were studied in nitrogen. The kinetic parameters were obtained using a model-free method and the reaction model was then derived by means of non-linear regression. The results showed that the decomposition of zinc hydroxide carbonate is a two-step reaction a reversible reaction of two-dimensional diffusion (D2), followed by an irreversible one of... 

Zinc stearate was synthetized [64] by precipitation method through steps neutralization of stearic acid by sodium hydroxide then double decomposition using zinc sulfate to precipitate zinc stearate. It was concluded that zinc stearate can be used as activator for sulfur vulcanization process instead of ZnO and stearic acid in absence and presence of fillers. 

Zinc Sulfate — (i Chemical Designations — Synonyms White vitroil Zinc sulfate heptahydrate Zinc vitriol Chemical Formula ZnS04 7Hj0 (Ii) Observable Characteristics — Physical State (as normally shipped) Solid Color Colorless Odor None (iii) Physical and Chemical Properties — Physical State at 15 V and 1 atm. Solid Molecular Weight 287.54 Boiling Point at I atm. Not pertinent (decomposes) Freezing Point (decompo.ses) 122 -212, 50 -100, 323 -373 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.96 at 20 C (solid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (das) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Not pertinent Heat of Decomposition Not pertinent (iv) Health Hazards Information — Recommended Personal Protective Equipment Dust mask, gog-... 

TATP also slowly decomposes by boiling in methanol solutions in presence of stannous chloride. Combustion of a toluene solution of TATP was proposed by Bellamy as a suitable method for disposal [43]. Extensive study of TATP decomposition by the action of chemical agents has recently been published by Oxley et al. [21]. They observed that TATP best decomposes by application of a solution of zinc sulfate or cupric chloride. The process takes only several hours at room temperature if these salts are used in combination with metallic zinc or copper. 

The spinning bath for viscose contains sulfuric acid (at about 10% concentration) for the decomposition of the xanthate and neutralization of the alkali. Sodium sulfate is formed anyway, but is also dissolved in large quantities (about 20%) in the spinning bath to control the coagulation process. A further addition is zinc sulfate (< 3%), again to control coagulation. 

In an atmosphere of nitric oxide, thermal decomposition produces barium nitrite, Ba(N02)2. Reactions with soluble metal sulfates or sulfuric acid yield barium sulfate. Many insoluble barium salts, such as the carbonate, oxalate and phosphate of the metal, are precipitated by similar double decomposition reactions. Ba(N03)2 is an oxidizer and reacts vigorously with common reducing agents. The solid powder, when mixed with many other metals such as aluminum or zinc in their finely divided form, or combined with alloys such as... 

Four milliliters of 1 AT aqueous sodium hydroxide solution is added to a mixture of 300 g. (5.2 moles) of acetone and 100 g. (0.86 mole) of aqueous 35% formaldehyde solution. The mixture is held at room temperature for 3-4 hours and then neutralized with 4 ml. oi 1 N hydrochloric acid. The excess acetone is distilled off on a water bath heated to 80-85°, and 2-4 g. of anhydrous zinc chloride is added to the residue. The mixture is distilled on an oil bath, and the distillate is collected as long as it comes over colorless. The distillate is treated with potassium carbonate, and the organic material is separated and dried over sodium sulfate. Distillation at 130 mm. pressure gives a 25-35% yield of methyl vinyl ketone boiling at 33-34°. Some decomposition occurs if the distillation is carried out at atmospheric pressure, where the product boils at 80°. 

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