Lead picrate

Lead Picrate. [CeHiCNOa O] 2Pb, mw 663.41 N 12.67% yel crysts mp, explds violently at 270-81°. Can be obtained by heating either the monohydrate or tetrahydrate to 150°. The tetrahydrate is obtained in the form of silky yel needles when an aq soln of PA is treated with Pb carbonate. The Ger method of prepn is given under Bleipikrat in Ref 9... 

VI. Uses. During the latter part of the nineteenth century and the early part of the present century, PA was widely used as the main expl charge of projectiles and bombs. This is no longer true, Indeed PA per se is hardly used as an expl. Its current limited expl-related use is primarily in the preparation of Explosive D (Ammonium Picrate) and Lead Picrate. It also finds some use as an intermediate in the manuf of dyes. There is some patent literature on the use of PA as a catalyst for polymerizations. For example, PA is claimed as catalyst in polybutadiene polymerizations (Ref 40), and for the prepn of an isobutylene-5-methyl-1,3,6 hepta-trieie copolymer (Ref 38)... 

A violent explosion of Picric Acid in a Manchester factory in 1887 was ascribed to the formation of picrates. Burning, molten Picric Acid flowed down onto lithopone, forming lead picrate which in consequence caught fire. The latter, being an initiator, detonated and caused the Picric Acid to detonate... 

The first dip given to a fusehead is known as the flashing composition and is of particular importance. Originally copper acetylide was used for this purpose, but it has been superseded by more stable materials. Three common compositions are based on lead picrate, lead mononitroresorcinate and a mixture of charcoal and potassium chlorate respectively. These materials are suspended in a solution of nitrocellulose in amyl acetate and amyl alcohol, known as Zapon. One or more dips, with intermediate drying, give a layer of suitable thickness. 

During the traditional qualitative inorganic analytical procedure, samples containing the lead and salicylate radicals can lead to the formation and possible detonation of lead picrate. This arises dining evaporation of the filtrate with nitric acid, after precipitation of the copper-tin group metals with hydrogen sulfide. Salicylic acid is converted under these conditions to picric acid, which in presence of lead gives explosive lead picrate. An alternative (MAQA) scheme is described which avoids this possibility. 

The fate of lead during energetics hydrolysis in the presence of picrate is not understood. Until more information becomes available on the speciation of lead and the solubility of lead picrate under the conditions of hydrolysis, the possibility of solid lead picrate formation cannot be dismissed. As a precautionary measure, lead-based propellants should be processed separately from tetryl and tetrytol, eliminating the possibility of lead picrate formation. 

The two studies, taken together, suggest that tetryl, not TNT, leads to the formation of picrate, since neither the LANL results nor the Holston results showed the formation of picrate in the absence of tetryl. If this is correct, the formation of lead picrate cannot occur when Composition B and M28 propellant are coprocessed, provided no tetryl contamination is present. The solubility of lead picrate in the reaction medium under consideration is not known. Because lead in solution at high pH is predominantly in the form of plumbite ion (HPb02), the concentration of free Pb2+ ions should be very low, and the solubility product of lead picrate would have to be exceedingly small for... 

Although precipitation of lead picrate is not likely to be a hazard during normal operation of a well-designed hydrolysis reactor, some data are still unavailable. During the hydrolysis runs at Holston, the material balance for lead was extremely poor. None of the runs of Ml propellant, each of which contained a little less than 4 pounds of lead in the feed, indicated any lead in the end-of-run hydrolysate analysis. Also, no lead was identified in the solids remaining at the end of any of the hydrolysis reactions. The inability to account for... 

Although the transport of dry lead picrate is forbidden by the Department of Transportation (DOT) (49 CFR 172.101), the addition of water desensitizes it. No hazard classification is available from DOT for wetted lead picrate, but silver picrate, which is similar in sensitivity, may not be shipped when dry but is classified as a flammable solid (Hazard Class/Division 4.1) when it is wetted with water by at least 30 percent by mass. 

Recommendation (Blue Grass) EH-1. Tetrytol should not be processed simultaneously with any lead-containing energetic material until such time as it can be confirmed that lead picrate will not precipitate from the hydrolysate. The solubility of lead picrate in the reaction medium should be determined as a function of temperature, and the lead in the reaction should be accounted for in a mass balance. 

Finding (Blue Grass) EFKE-8. The Eco Logic process for handling energetics will cause lead-containing M28 propellant to mix with tetrytol when rockets with tetrytol boosters are treated. The combination might lead to the formation of lead picrate. 

This combination might lead to the formation of lead picrate. 

Recommendation (Blue Grass) GA-1. The hydrolysis streams for the processing of propellant and burster materials must be kept separate until the formation of lead picrate has been ruled out. 

Chlorpromazine formed an insoluble 1 1 complex with lead picrate, and 5 3 complexes with the picrates of cadmium, copper, and zinc [70]. The sample (0.1 g) was dissolved in 15 mL of 95% ethanol, and the solution adjusted to pH 9 with 0.1 N NaOH. After adding 25 mL of a 0.02 M picrate reagent (30 mL of Pb), the solution was set aside for 2 hours. The precipitate was collected on a sintered glass fuimel, and the unconsumed metal in the filtrate was titrated directly with 0.02M EDTA at pH 10.4 (after adding 0.5 g of potassium sodium tartrate for Pb). Eriochrome black T was used as the indicator. 

Pb azide, Pb nitrophenols, Pb triethanol-ammonium perchlorate and PETN or RDX, with a sheath spun from filaments of a thermo plastic material or a ductile metal such as bronze) Ad 159) J.F. Kenney, USP 3293091(1966) CA 67, 7089(1967) [Primary expl mixts contg 46% of complex clathrate inclusion salts (as shown by X-ray diffraction data) of basic lead picrate, such as Pb(C5H2N3O7)2-Pb(OH)2-Pb(N03)2.-Pb(OAc)2, 50% Ba nitrate 4% Tetracene]... 

Mercuric Fulminate MF + 10% KClOg MF + 20% KCIO3 Silver Fulminate Lead Azide Silver Azide Mercurous Azide Lead Styphnate Silver Acetylide Lead Picrate... 

Lead picrate Lead styphnate Lead styphnate Lead-TNP Lewisite... 

Methylpicric acid Lead styphnate Lead picrate Picric acid TPG TNT... 

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