Perchlorates, inorganic, aqueous solution

PERCHLORATES, inorganic, aqueous solution, n.o.s. temperature controlled... 

In view of the results discussed in Section III,C,7, it is not surprising that photolysis of N-alkylanthranilium perchlorates in aqueous solution leads to the formation of 3- and 5-hydroxy-2-alkylaminoacylbenzenes.240 Addition of inorganic ions (e.g., Cl-, Br-, or SCN-) produces the correspondingly... 

Anhydrous perchloric acid is a powerful oxidizing agent that reacts explosively with many organic and inorganic materials. On decomposition, various gaseous products are formed. However, aqueous solutions of perchloric acid are not oxidizing at room temperature. This is explained on the basis of kinetic activation barriers. Most metals form perchlorate salts, and even molecular compounds, such as NO and NO2, also react with it to form ionic compoimds such as [NO]+ [0104]. Ammonium perchlorate is used as a solid-fuel propellant, particularly in missiles. Potassium perchlorate is also used in pyrotechnic formulations such as fireworks and flares. 

It can be prepared by neutralizing aqueous solution of hydrazine with IICIO4 (95 ] or by double exchange of hydrazine salt with an inorganic perchlorate dissolved in lower alcohols (98]. 

Raman spectra of aqueous solutions of inorganic salts have been studied extensively. For example, Hester and Plane" observed polarized Raman bands in the 400-360 cm region for the nitrates, sulfates, and perchlorates of Zn( II), Hg(ll), and Mg(ll), and assigned them to the MO stretching modes of the hexacoordinated aquo complex ions. 

In polyacrylonitrile appreciable electrostatic forces occur between the dipoles of adjacent nitrile groups on the same polymer molecule. This restricts the bond rotation and leads to a stiff, rodKke structme of the polymer chain. As a result, polyacrylonitrile has a very high crystalline melting point (317°C) and is soluble in only a few solvents, such as dimethylformamide and dimethylacetamide, and in concentrated aqueous solutions of inorganic salts, such as calcium thiocyanate, sodium perchlorate, and zinc chloride. Polyacrylonitrile cannot be melt processed because its decomposition temperature is close to the melting point. Fibers are therefore spun from solution by either wet or dry spinning (see Chapter 2). 

Notwithstanding the non-specific role of water in many non-aqueous solutions, in some cases it may have specific effects due to ion-water interactions which depend on the particular nature of the ions and solvent. Thus the conductance of associated AgNOa and (CHajaTlI in dimethyl-formamide increase with the water content in contrast to the decrease found for dissociated salts In methanol and ethanol the conductance of perchloric acid (and presumably of other Inorganic acids) decreases significantly upon addition of 0.3 % water. This was attributed to a change in the proton transport mechanism. 

Until recently, the majority of chemists considered R(III) to be, by far, the most frequent oxidation state, and almost entering the definition of R. This is less true today as the effort dedicated to solid-state chemistry is comparable to that devoted to solution chemistry. However, it is also true that acidic aqueous solutions with pH between —1 and 3, and having an oxidizing character between E° = 0 and -f 1 V, using typical inorganic acids, exclusively allow detection of R(III) of all 17 R, and, actually, in less than 4 molar perchlorate or chloride, the aqua ions of yttrium and... 

The most important methods for the preparation of polyacrylonitrile are solution polymerization and suspension polymerization. The former method is particularly convenient, since when a solvent for the polymer is used, the resulting solution may be utilized directly for fibre spinning. Concentrated aqueous solutions of inorganic salts such as calcium thiocyanate, sodium perchlorate and zinc chloride make suitable solvents suitable organic solvents include dimethylacet amide, dime thy Iformamide and dimethylsulphoxide. Emulsion polymerization suffers from the disadvantage that the monomer has appreciable water-solubility and the formation of polymer in the aqueous phase can lead to coagulation of the latex. This tendency is reduced by the addition of ethylene dichloride to the system. 

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