Potassium picrate

Detection of Potassium in the presence of Sodium. Add a cold saturated aqueous solution of sodium picrate to a solution of potassium chloride. A rapid precipitation of the less soluble potassium picrate occurs, even from a i°o solution of potassium chloride. 

The amino add analysis of all peptide chains on the resins indicated a ratio of Pro Val 6.6 6.0 (calcd. 6 6). The peptides were then cleaved from the resin with 30% HBr in acetic acid and chromatogra phed on sephadex LH-20 in 0.001 M HCl. 335 mg dodecapeptide was isolated. Hydrolysis followed by quantitative amino acid analysis gave a ratio of Pro Val - 6.0 5.6 (calcd. 6 6). Cycll2ation in DMF with Woodward s reagent K (see scheme below) yielded after purification 138 mg of needles of the desired cyc-lododecapeptide with one equiv of acetic add. The compound yielded a yellow adduct with potassium picrate, and here an analytically more acceptable ratio Pro Val of 1.03 1.00 (calcd. 1 1) was found. The mass spectrum contained a molecular ion peak. No other spectral measurements (lack of ORD, NMR) have been reported. For a thirty-six step synthesis in which each step may cause side-reaaions the characterization of the final product should, of course, be more elaborate. 

Potassium picrate [573-83-1] M 267.2. Crystd from water or 95% EtOH, and dried at room temperature in vacuum. It is soluble in 200 parts of cold water and 4 parts of boiling water. THE DRY SOLID EXPLODES WHEN STRUCK OR HEATED. 

Szava, Factors which Influence Thermal Decomposition of Potassium Picrate , 8th Symp Combstn (1962), 863—72... 

The conductivity of pyridine is considerably increased by addition of iron carbonyl and corresponds to that of potassium picrate in the same solvent 91 Likewise, DMSO, alcohols, or ammonia95,as well as soft ligands such as triphenylphosphine, may serve as donor molecules 10°1 ... 

Trimethyldecahydroquinolinium picrate, 3765 Ammonium picrate, 2322 Calcium picrate, 3430 Cobalt(II) picramate, 3460 Copper(II) picrate, 3432 Lanthanum picrate, 3741 Lead(II) picrate, 3436 Manganese picrate hydroxide, 3742 Mercury(II) picrate, 3433 S-7-Methylnonylthiouronium picrate, 3737 Nickel picrate, 3435 Potassium picrate, 2085 Sodium picrate, 2086 Zinc picrate, 3437... 

The dependence of explosion temperature upon rate of heating is almost always linear, with the exception of potassium picrate... 

Potassium chlorate Potassium chlorate Potassium nitrate Potassium perchlorate Potassium picrate PSE... 

Glauber, Johann Rudolph [1603 (or 1604)—1668]. Dutch (or German) "iaerochemist" [belonging to the 16th century school of medicine basedon principles of Swiss physician Paracelsus (1493— 1541)] who prepd expl substances Potassium Picrate and Ammonium Nitrate. He also prepd the salt known as "Glauber salt" (cryst Na sulfate) and pure nitric and hydrochloric acid. 

Addition of a second crown produces the loose ion pair A, Cr,K, Cr. However, the complexation constant for adding the second crown is 1800 M 1 for the fluorenyl carbanion and only 200 M 1 for the picrate salt. The lower value for picrate may in part be due to less charge delocalization, e.g., the free ion dissociation constant for potassium fluorenyl in TEF is 1.6 x 10 7M (18) as compared to 9.2 x 10 M for potassium picrate (17). The two N02 substituents close to the 0 bond in picrate may also hinder the enlargement of this ionic bond and the insertion of a crown ether molecule because of electronic or sterlc effects. 

Loose ion pairs of such charge-localized oxyanion salts as potassium t-butoxlde may be difficult to form. This alkoxide is a tetrameric aggregate in THF (20). and crown addition breaks it down to the more reactive monomeric form. It is unlikely that with benzo-15-crown-5 a 2 1 crown-K loose ion pair can be formed similar to that found with potassium picrate or potassium fluorenyl. However, external complexation itself will slightly stretch the . bond, and this can have a profound effect on the anion reactivity (21). 

In 1861 Designolle [33] suggested using potassium nitrate mixed with metal picrates, mainly potassium picrate, as a propellant substitute for ordinary black-... 

Blackpowder and small arms powder contained 9-16% and ca. 23% potassium picrate, respectively. 

The new propellant was promising but the nitrocellulose smokeless powder invented soon afterwards superseded all mixtures containing potassium nitrate and similar salts, that give a number of solid particles when exploded. For a time in the United States various mixtures were still used instead of blackpowder—chiefly for sporting purposes. E.g. Gold Dust Powder (Starke [36]) consisted of 55% ammonium picrate, 25% potassium picrate and 20% ammonium bichromate. Soon, however, early in the nineteenth century, the use of these mixtures was discontinued. 

Glauber in 1742 reacted nitric acid with wool or horn and produced picric acid in the form of lead or potassium picrate. In 1771, Woulfe... 

Det the content of potassium picrate either colorimetrically or gravimetrically, such as by pptn with Pb acetate... 

Figure 8 The molecular structure of potassium picrate (31) dimer (reproduced with permission from reference 222)...

An extensive range of synthetic analogues of valinomycin and the enniatins has been prepared and investigated these studies have been fully described in ai monograph.532 Synthetic peptides have also been prepared and their complexing properties investigated for example [L-Val-D-Pro-D-Val-L-Pro]3 reacts with potassium picrate to give an isolable 1 1 complex which is expected to have a structure similar to that of the K+ complex of (137).557 More detailed studies have been made on the complexation properties of the small synthetic peptides [L-Pro-Gly]3 and [L-Pro-Gly]4. 

Detonators were manufactured abroad and sold for a time under Nobel s patent, A. V. Newton (from A. Nobel, Paris), Brit. Pat. 16,919 (1887), covering the use, instead of fulminate, of a granulated mixture of lead picrate, potassium picrate, and potassium chlorate, but the invention apparently contributed little to the advance of the explosives art. 

KCIO4 (c). Berthelot and Vielle4 determined the heat of decomposition of KCIO4 (c) into KC1 (c) and 02 (g), in a tomb calorimeter using potassium picrate and ammonium picrate as the auxiliary combustibles. Their data yield, for KC104 (c), Qf= 110.9 and 113.0, respectively. 

Potassium 2,4,6-trinitrophenoxide, see Potassium picrate, 2078 Potassium 2,4,6-trinitrotoluene, 2679... 

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