Picrates


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Picrates

 

salts of picric acid, or 2,4,6-trinitrophenol. Metal picrates are crystals ranging from yellow to red in color; Li and Na salts are moderately soluble in water, whereas salts of K and heavy metals, such as Pb, Cu, and Ca, are poorly soluble. Pi-crates are obtained by the action of metal hydroxides or carbonates on picric acid solutions, as well as by exchange reactions between barium or lithium picrates and the sulfates or nitrates of some metals, most often Pb.

Picrates are highly sensitive to mechanical effects and are readily inflammable and quick-burning explosives (the combustion rates for magnesium, potassium, and lead picrates at a pressure of 5 meganewtons per sq m, or 50 kilograms-force per sq cm, are 1.2, 3.5, and 21 cm sec, respectively). They have high thermal stability (particularly potassium and magnesium salts).

Organic bases are often isolated from mixtures and identified in picrate form. The term “picrates” is also used to designate complexes formed for aromatic hydrocarbons and picric acid.

References in periodicals archive ?
Where A 0 and A are the initial and final concentrations of picrate ions, before and after the extraction, respectively.
The copolymer 6 (25 mg) was shaken with a 10 mL of aqueous solution containing 2.5x10 -5 M metal picrate in a stoppered glass flask plunged in a thermostated water bath kept up at 25 AoC for 1 h and finally filtered off.
For this purpose, aqueous solutions of the picrate salts of some transition metals (Cu+2, Co+2, Cd+2 , Ni+2 ve Hg+2) and CH2Cl2 solution of the compound 3 and copolymer 6 were activated in equal volumes [31].
It was fulfilled by stirring solid state copolymer with the metal picrate solutions for one hour at 25AdegC.
Thus, a Na-dichromate extraction study was also conducted to scrutinize the anion transfer properties of the synthesized compounds, in addition to metal picrate extraction studies.
Keywords: Metal picrate; Cryptand; Transition metal cation; Solvent extraction.
For this purpose picrate was used as a counter ion to measure absorbance of aqueous phase after extraction.
To adjust pH of metal picrate solutions Jenway 3040 Ionalyzer was used.
Picrate and ligand concentrations were 5.0A-10-6 M and 1.5A-10-4 M respectively.
The ligand concentration effect on the distribution ratio was investigated at constant picrate concentration to determine the complex stoichiometry of extracted species.