Phosphorus preservation

McCarthy and coworkers (74) at the Australian Forest Products Laboratory reported that a pressure treatment for pine posts with zinc-copper-chromium-arsenic-phosphorus preservative produced a leach-resistant treatment having both fire retardancy and preservation against decay. This treatment system is reported to have commercial application in Australia. 

McCarthy et al. (97) tested a zinc, copper, chromium, arsenic, phosphorus preservative on fence posts. The addition of the zinc and phosphorus eliminated the afterglow problem caused by this treatment. However, incorporation of the phosphorus reduced the effectiveness of the decay resistance. 

Phosphorus exists as white and red phosphorus. The former allotrope may be preserved in the dark at low temperatures but otherwise reverts to the more stable red form. The white form is a waxy, translucent, crystalline, highly-toxic solid subliming at room temperature and inflaming in air at 35°C, so it is handled under water. The red form is a reddish violet crystalline solid which vaporizes if heated at atmospheric pressure and condenses to give white phosphorus. The red form ignites in air at 260°C. Both are insoluble in water, and white phosphorus can be stored beneath it. Phosphorus forms a host of compounds such as phosphine, tri- and penta-halides, tri-, tetra- and penta-oxides, oxyacids including hypophosphorous, orthophosphorous and orthophosphoric acids. 

Potassium nitrate is also found in pills for backache and joint pain. It makes a decent plant fertilizer, providing nitrogen and potassium but no phosphorus. As an oxidizer, it is an ingredient in stump removers that hastens the decay of tree stumps. And it is used as a preservative in some salted meats like nitrites, it helps to preserve the color of the meat. 

We discovered a complementary procedure for conversion of OMen to other functional groups. The ester P-OMen bond was shown to be cleaved in a stereoselective manner reductively [85,86]. The cleavage takes place with almost complete preservation of stereochemical integrity at phosphorus. The reducing agents are usually sodium or Hthium naphthalenide, lithium biphenyUde, and Hthium 4,4 -di-fert-butylbiphenyl (LDBB). The species produced is then quenched with an alkyl hahde or methanol to afford tertiary or secondary phosphines, respectively (Scheme 5b). Overall, the displacement reaction proceeds with retention of configuration. 

The incorporation of phosphorus yields fourfold-coordinated P atoms, which are positively charged, as phosphorus normally is threefold coordinated. This substitutional doping mechanism was described by Street [52], thereby resolving the apparent discrepancy with the so-called S N rule, with N the number of valence electrons, as originally proposed by Mott [53]. In addition, the incorporation mechanism, because charge neutrality must be preserved, leads to the formation of deep defects (dangling bonds). This increase in defect density as a result of doping explains the fact that a-Si H photovoltaic devices are not simple p-n diodes (as with crystalline materials) an intrinsic layer, with low defect density, must be introduced between the p- and n-doped layers. 

Noteworthy NMR studies involving nuclei other than phosphorus have been carried out for some P-chloro-NHPs where the possible occurrence of spontaneous P-Cl bond dissociation was probed by II NMR titrations and 35C1 NMR [20], and for P-cyclopentadienyl derivatives where measurement of solid-state 13C CP-MAS NMR spectra allowed one to substantiate the preservation of the circumambulatory ring migration of cyclopentadienyl groups in the solid state [47], Several neutral and cationic derivatives have also been studied by 15N NMR [20, 53],... 

The interaction of cyclic aminomethylphosphines may proceed either with opening of the ring or with its preservation (89IZV1375). 1,3,5-Diaza-phosphorinane (43) with R = C6H4Me-p at the nitrogen atoms, when treated by diborane, opens its ring with rupture of the C—N bond in the N—C—N fragment and coordination of the borane molecule at the phosphorus atom [Eq. (47)]. 

Used industrially as a chemical intermediate in the production of rayon, carbon tetrachloride, xanthogenates, flotation agents, and pesticides used in the cold vulcanization of vulcanized rubber, in adhesive compositions for food packaging as a solvent for phosphorus, sulfur, selenium, bromine, iodine, fats, resins, rubbers, waxes, lacquers, camphor, resins and in the production of optical glass, paints, enamels, varnishes, paint removers, tallow, putty preservatives, rubber cement, soil disinfectants, explosives, rocket fuel, and electronic vacuum tubes. 

Preservation of readily biodegradable substrates in sewers may be crucial in case of denitrification and phosphorus removal in advanced treatment processes. 

The results in Figure 6.9 show that the production rate of readily biodegradable substrate (Ss) by the anaerobic hydrolysis is larger than the removal rate. It is a major result that readily biodegradable substrate is not just preserved but produced. This fact has positive implications on the subsequent treatment processes in terms of denitrification and biological phosphorus removal. On the other hand, it is negative if wastewater treatment is only required in terms of BOD removal. 

Environmental water samples to be analyzed for phosphate are not stored in plastic bottles unless kept frozen, because phosphates can be absorbed onto the walls of plastic bottles. Mercuric chloride, used as a preservative and acid (such as the nitric acid suggested for metals above), should not be used unless total phosphorus is determined. All containers used for water samples to be used for phosphate analysis should be acid rinsed, and commercial detergents containing phosphates should not be used to clean sample containers or laboratory glassware. 

It is worth mentioning at this point that the formation of a a -phosphorus from a -phosphorus resulted in a-aromatic compounds in the case of the l//-phosphirenium cation as well. Disubstitution at the phosphorus in l//-phosphirenium cation (5) resulted in the preservation of aromaticity with proper substituents (fluorine) in 36, as a result of the interaction with PF2 a -orbitals,as indicated by isodesmic reactions. A similar phenomenon has been observed also for 1,1-difluorocyclopropene, 1,1-bissilylcyclopentadiene, and 1,1-bisstannylcyclopen-tadiene. In the latter case, the phenomenon has been called hyperconjugate aromaticity . The effect of... 

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