Pyrophoric

Many types of ammunition are used for testing, training, and ceremonial purposes  

Charges, shaped without detonator, see Explosive Articles, p.69 

Propellant, single, double or triple base, see Explosives and Class /, p.74 

Explosive, see Explosives and Class 1, p.74 Flammable liquid, see Flammable Liquids and Class 3, p.96 

---

Raney nickel A special form of nickel prepared by treating an Al-Ni alloy with NaOH solution. The nickel is left in a spongy mass which is pyrophoric when dry. This form of nickel is a most powerful catalyst, especially for hydrogenations. 

In the 1950 s, crude oils were either corrosive (sour), or non-corrosive (sweet). Crudes containing more than 6 ppm of dissolved H2S were classed as sour because, beyond this limit, corrosion was observed on the walls of storage tanks by formation of scales of pyrophoric iron sulfides. 

Finely divided lead, when heated in air, forms first the lead(II) oxide, litharge , PbO, and then on further heating in an ample supply of air, dilead(II) lead(IV) oxide, red lead , Pb304. Lead, in a very finely divided state, when allowed to fall through air, ignites and a shower of sparks is produced. Sueh finely divided powder is said to be pyrophoric . It can be prepared by carefully heating lead tartrate. 

It is a black powder, often pyrophoric, and is non-stoichiometric. the formula Feo.950 more correctly representing its average composition. 

Catalysts reduced with formaldehyde contain no adsorbed hydrogen and are less pyrophoric. 

Finely divided hafnium is pyrophoric and can ignite spontaneously in air. Care should be taken when machining the metal or when handling hot sponge hafnium. 

Cerium is a component of misch metal, which is extensively used in the manufacture of pyrophoric alloys for cigarette lighters. While cerium is not radioactive, the impure commercial grade may contain traces of thorium, which is radioactive. The oxide is an important constituent of incandescent gas mantles and is emerging as a hydrocarbon catalyst in self cleaning ovens. In this application it can be incorporated into oven walls to prevent the collection of cooking residues. 

Gr. neos, new, and didymos, twin) In 1841, Mosander, extracted from cerite a new rose-colored oxide, which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals. 

Uranium exhibits three crystallographic modifications as follows alpha —(688C)—> beta —(776C)—> gamma. Uranium is a heavy, silvery-white metal which is pyrophoric when finely divided. 

Finely divided uranium metal, being pyrophoric, presents a fire hazard. 

Disposal of spent hydrogenation catalyst requires a special chemical waste landfill because of its nickel content and the fact that oil-soaked catalysts tend to be pyrophoric. Compared to disposal costs, reprocessing to recover the nickel may become economically viable. 

The volatiles contents of product chars decreased from ca 25—16% with temperature. Char (lower) heating values, on the other hand, increased from ca 26.75 MJ /kg (11,500 Btu/lb) to 29.5 MJ /kg (12,700 Btu/lb) with temperature. Chars in this range of heating values are suitable for boiler fuel apphcation and the low sulfur content (about equal to that of the starting coal) permits direct combustion. These char products, however, are pyrophoric and require special handling in storage and transportation systems. 

Reduction. Hafnium oxide can be reduced using calcium metal to yield a fine, pyrophoric metal powder (see Calciumand calciumalloys). This powder contains considerable oxygen contamination because of oxygen s high solubility in hot hafnium, and caimot be consoHdated into ductile metal. To obtain low oxygen ductile hafnium, the feed must be an oxygen-free halide compound such as hafnium tetrachloride or potassium hexafluorohafnate [16871-86-6]. 

Physical Properties. An overview of the metallurgy (qv) and soUd-state physics of the rare earths is available (6). The rare earths form aUoys with most metals. They can be present interstitiaUy, in soUd solutions, or as intermetaUic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and weU characteri2ed. AU impurity levels in the sample should be known. Some properties of the lanthanides are Usted in Table 3. 

At the beginning of the twentieth century, the incandescent mantle, utilising the candoluminescence of a mixture of thorium (95% weight) and cerium oxides was developed. The pyrophoricity of rare-earth metals led to the invention of the lighter flint made through the alloying of iron and mischmetal. Since that time, numerous other appHcations have developed to coincide with the availabiUty of the rare-earth compounds on an industrial scale and having a controlled purity. 

ButyUithium is available in hydrocarbon media, eg, hexane, heptane, cyclohexane, and toluene in several concentrations, eg, 15, 25, and 90 wt %. It is shipped commercially in 10-, 19-, 106-, 216-, and 454-L cylinders and 1900-L (500-gal) tanks and in bulk in 19,000-L (5,000-gal) tank tmcks and 30,300-L (8,000-gal) rail tank cars. For shipment purposes, / -butyUithium is described as a pyrophoric fuel and is classified as a flammable Hquid. As such, full precautions should be taken according to handling instmctions (100). 

Like //-butyUithium, j iZ-butyUithium is infinitely soluble in most hydrocarbons, such as pentane and hexane. Its solutions in hexane are flammable and pyrophoric and therefore should be handled like //-butyUithium (96,100). j iZ-ButyUithium also is very soluble in ethers, but the ether solutions must be kept cold because ether cleavage is more rapid than in the presence of //—butyUithium (122). j iZ-ButyUithium has a t 2 of 2 d at 25°C in di-//-butyl ether and of 1 d at 25°C in di-//-hexyl ether. 

ButyUithium is available as a 15—20 wt % solution in //-pentane or heptane. Noticeable decomposition occurs after alb reflux in heptane (bp 98.4°C) but not after a 15 min reflux in ben2ene (bp 80.1°C) or hexane (bp 68°C). /-ButyUithium in pentane or heptane is more stable than //-butyUithium in hexane (125). Solutions of /-butyUithium in pentane and heptane are flammable Hquids and are considered pyrophoric. The /-butyl compound is more reactive than either the n- and sec-huty. Di-//-butylether is cleaved by /-butyUithium in 4—5 h at 25°C, compared to the 2 d for j iZ-butyUithium and 32 d for //-butyUithium (126). /-ButyUithium can be assayed by aU of the techniques used for //-butyUithium. /-ButyUithium is a useful reagent in syntheses where the high reactivity of the carbon—lithium bond and smaU si2e of the lithium atom promote the synthesis of stericaUy hindered compounds, eg,... 

Stabilized lithium acetyhde is not pyrophoric or shock-sensitive as are the transition-metal acetyhdes. Among its uses are ethynylation of halogenated hydrocarbons to give long-chain acetylenes (132) and ethynylation of ketosteroids and other ketones in the pharmaceutical field to yield the respective ethynyl alcohols (133) (see Acetylene-derived chemicals). 

Phenyllithium. PhenyUithium [591-51-5] C H Li, forms colorless, monoclinic, pyrophoric crystals that do not melt before decomposition at... 

Lithium ion is commonly ingested at dosages of 0.5 g/d of lithium carbonate for treatment of bipolar disorders. However, ingestion of higher concentrations (5 g/d of LiCl) can be fatal. As of this writing, lithium ion has not been related to industrial disease. However, lithium hydroxide, either dHectly or formed by hydrolysis of other salts, can cause caustic bums, and skin contact with lithium haHdes can result in skin dehydration. Organolithium compounds are often pyrophoric and requHe special handling (53). 

Titanium is resistant to nitric acid from 65 to 90 wt % and ddute acid below 10 wt %. It is subject to stress—corrosion cracking for concentrations above 90 wt % and, because of the potential for a pyrophoric reaction, is not used in red filming acid service. Tantalum exhibits good corrosion resistance to nitric acid over a wide range of concentrations and temperatures. It is expensive and typically not used in conditions where other materials provide acceptable service. Tantalum is most commonly used in appHcations where the nitric acid is close to or above its normal boiling point. 

Although phosphine [7803-51-2] was discovered over 200 years ago ia 1783 by the French chemist Gingembre, derivatives of this toxic and pyrophoric gas were not manufactured on an industrial scale until the mid- to late 1970s. Commercial production was only possible after the development of practical, economic processes for phosphine manufacture which were patented in 1961 (1) and 1962 (2). This article describes both of these processes briefly but more focus is given to the preparation of a number of novel phosphine derivatives used in a wide variety of important commercial appHcations, for example, as flame retardants (qv), flotation collectors, biocides, solvent extraction reagents, phase-transfer catalysts, and uv photoinitiators. 

Some phosphoms—hydrogen compounds are pyrophoric, eg, diphosphine [13445-50-6] 2 4 common impurity in phosphine. Such contaminated phosphine usually ignites spontaneously on contact with air. 

All phosphoms oxides are obtained by direct oxidation of phosphoms, but only phosphoms(V) oxide is produced commercially. This is in part because of the stabiUty of phosphoms pentoxide and the tendency for the intermediate oxidation states to undergo disproportionation to mixtures. Besides the oxides mentioned above, other lower oxides of phosphoms can be formed but which are poorly understood. These are commonly termed lower oxides of phosphoms (LOOPs) and are mixtures of usually water-insoluble, yeUow-to-orange, and poorly characteri2ed polymers (58). LOOPs are often formed as a disproportionation by-product in a number of reactions, eg, in combustion of phosphoms with an inadequate air supply, in hydrolysis of a phosphoms trihahde with less than a stoichiometric amount of water, and in various reactions of phosphoms haUdes or phosphonic acid. LOOPs appear to have a backbone of phosphoms atoms having —OH, =0, and —H pendent groups and is often represented by an approximate formula, (P OH). LOOPs may either hydroly2e slowly, be pyrophoric, or pyroly2e rapidly and yield diphosphine-contaminated phosphine. LOOP can also decompose explosively in the presence of moisture and air near 150° C. 

---