Phosphine exposure

Toxicity. Lethality is the primary ha2ard of phosphine exposure. Phosphine may be fatal if inhaled, swallowed, or absorbed through skin. AH phosphine-related effects seen at sublethal inhalation exposure concentrations are relatively small and completely reversible. The symptoms of sublethal phosphine inhalation exposure include headache, weakness, fatigue, di22iness, and tightness of the chest. Convulsions may be observed prior to death in response to high levels of phosphine inhalation. Some data are given in Table 2. 

Deliberations on phosphine AEGL development identified the possibility that children are more susceptible to phosphine exposure. This condition was suggested by two case reports describing the deaths of children, but not adults, after comparable phosphine exposures. However, both the children and the adults in question were present in somewhat restricted environments, suggesting comparable exposure levels. Based on these case reports, the NAC/AEGL Committee concluded that children may be more susceptible to phosphine exposure and selected UFs that would provide additional protection for children. 

There is evidence that long-term phosphine exposure by individuals involved in the application of pesticides resulted in chromosome damage. Chronic exposure to very low levels of phosphine may result in altered motor, visual, and speech skills. Neither aluminum phosphide nor phosphine gas exhibit carcinogenicity in humans, or result in reproductive or developmental effects. Although definitive evidence is lacking, it is assumed that phospine is an in vivo inhibitor of oxidative phosphorylation. 

Inhalation is the major route of phosphine exposure. Phosphides may be absorbed through broken skin causing systemic toxicity. Phosphine gas produces... 

Burgess JL Phosphine exposure from a methamphetamine laboratory investigation. J Toxicol ain Tox/co/2001 39(2) 165-168. [PMID 11407503] (Case report.)... 

Individuals exposed to phosphine at concentrations exceeding the TLV, or those exhibiting symptoms of phosphine exposure, should receive professional medical care immediately. First aid consists of moving the exposed person (with minimum exertion) to an uncontaminated area and administering pure oxygen, bronchodilators (such as albuterol) and inhalant anticholinergics (such as Atrovent) if chest symptoms occur. [1]... 

Phosphine has an 8-h time-weighted average exposure limit of 0.3 ppm (13). Under alkaline conditions the rate of PH formation is high. At neutral or acidic pH, the PH generation is slow but stiU very ha2ardous if the PH is allowed to accumulate in a confined vapor space. The safest commercial handling conditions for molten phosphoms are generally considered to be from pH 6 to 8 at 45—65°C. 

The lustrous black crystals of trirhenium nonabromide are not rapidly degraded on exposure to the atmosphere the crystals can be stored over desiccants for months without evidence of decomposition. The bromide dissolves fairly slowly and sparingly in ether and acetone. In methanol, the bromide gives yellow-orange solutions, but it is solvolyzed within minutes. Similarly, the bromide dissolves in water at room temperature to yield a violet solution which darkens rapidly, yielding a black precipitate, presumably the hydrated dioxide.9 Contrary to published work,10 the bromide does dissolve in ammonia with solvolysis, as is evidenced by lines attributable to ammonium bromide in x-ray diffraction data of the solid residue recovered from liquid ammonia solutions.11 Trirhenium nonabromide reacts with Lewis bases such as phosphines and amines to form a series of complexes of the type (base) 3Re3Br9.6... 

Exposure of the benzo[b]thiophene derivative 44 to a palladium catalyst in the presence of tri(2-furyl)phosphine (TFP) as the ligand led to the product 45, which incorporated two heterocyclic units from the starting material. The mechanistic aspects of this transformation were also discussed, which appears to involve palladacycle intermediates <06JA722>. 

In the particular case of InP, protection of the surface is necessary because direct exposure of an InP sample to a rf hydrogen plasma causes a strong surface decomposition with the formation of phosphine and metallic indium islands (Thomas et al., 1988). Hydrogen diffusion into InP Zn can be successfully performed through an undoped correctly lattice matched... 

One of the possible reasons of the drop of the initiation rate could lie in the fast consumption of the photoinitiator. With a phosphine oxide photoinitiator (LucirinTPO), as much as 75% of this compound was destroyed within 0.2 s of UV exposure at a light intensity of 400 mW cm 2 (Figure 7). When the light was cut off at that time (rj=0), the polymerization was found to continue to proceed nearly as fast as upon continuous irradiation. The fact that the polymerization is only slightly faster upon continuous irradiation than in the dark suggests that rj has already dropped to a low value when (Rp)max is being measured, at 20% conversion. The important post-polymerization, which lasts only a few seconds, is due to the high concentration of macroradicals that continue to polymerize in the dark. 

Green et al. observed that the tantalum complex 101 is converted into the bicyclic complex 109 after prolonged exposure to sodium and trimethyl-phosphine.930 Two phosphine ligands of 101 are easily displaced by butadiene, affording the complex 110, while treatment of 109 with dihydrogen leads to the reduction of the metallic center. In both cases, the metallacycle remains intact.930... 

Barbosa A, Bonin AM Evaluation of phosphine genotoxicity at occupational levels of exposure in New South Wales, Australia. Occup Environ Med 51(10) 700-705, 1994... 

The spontaneously inflammable nature of the higher phosphines decreases with increasing phosphorus content. At room temperature or on exposure to light, phosphorus-rich, yellow, solid phosphines are rapidly formed these can also be obtained directly by thermal decomposition of diphosphine. The literature on these types of higher phosphorus hydrides which are, in general, solid and are thus refered to as solid phosphorus hydrides is abundant and... 

Primary and secondary alkyl phosphines autoxidize rapidly. In fact lower members may ignite on exposure to air. However, reaction paths appear to involve both P—H bond cleavage and participation of phos-phoranyl radicals (discussed below). 

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