Phosphorus boxes

The old phosphorus boxes contained preparations which absorbed moisture from the air with the evolution of heat. The resulting rise of temp, favoured combustion. For example, the mixture of yellow and red phosphorus, and phosphoric and phosphorous oxides and acids, obtained by blowing a jet of air into a flask with some warmed phosphorus, may ignite when exposed to moist air. The phosphoric oxides keep the phosphorus in a fine state of subdivision. J. Pelouze obtained a luminous mixture by melting phosphorus with phosphoric oxide, or calcined magnesia, or lime. M. Saltzer melted phosphorus with about one-third its weight of wax sent a jet of air into the flask until the phosphorus inflamed and then closed the flask. E. Benedix fused a mixture of powdered cork, beeswax, phosphorus, and naphtha. The mass fired spontaneously at 20°, or at a lower temp, if breathed upon. 

Phosphorus pentabromide [7789-69-7] M 430.6, m <100 , b 106 (dec). Dissolved in pure nitrobenzene at 60°, filtering off any insoluble residue on to sintered glass, then crystallised by cooling. Washed with dry Et20 and removed the ether in a current of dry N2. (All manipulations should be performed in a dry-box.) [Harris and Payne J Chem Soc 3732 1958]. Fumes in moist air because of hydrolysis. HARMFUL VAPOURS. 

Phosphorus pentacfaloride [10026-13-8] M 208.2, m 179-180 (sublimes). Sublimed at 160-170° in an atmosphere of chlorine. The excess chlorine was then displaced by dry N2 gas. All subsequent manipulations were performed in a dry-box [Downs and Johnson J Am Chem Soc 77 2098 1955]. Fumes in moist air. HARMFUL VAPOURS. 

We build Lewis structures according to the six-step procedure described in the box. Building Lewis Structures. Learning how to apply these steps is best done through examples. We begin with phosphorus trichloride, PCI3. ... 

MRH Barium chlorate 5.06/83, calcium chlorate 5.61/77, potassium chlorate 6.07/76, sodium bromate 4.98/80, sodium chlorate 7.32/75, zinc chlorate 6.11/76 Dry finely divided mixtures of red (or white) phosphorus with chlorates, bromates or iodates of barium, calcium, magnesium, potassium, sodium or zinc will readily explode on initiation by friction, impact or heat. Fires have been caused by accidental contact in the pocket between the red phosphorus in the friction strip on safety-match boxes and potassium chlorate tablets. Addition of a little water to a mixture of white or red phosphorus and potassium iodate causes a violent or explosive reaction. Addition of a little of a solution of phosphorus in carbon disulfide to potassium chlorate causes an explosion when the solvent evaporates. The extreme danger of mixtures of red phosphorus (or sulfur) with chlorates was recognised in the UK some 50 years ago when unlicenced preparation of such mixtures was prohibited by Orders in Council. 

For phosphorus, Cdeep/C river = 3 0 and Csurface/Qver = 0.15, SO = 0.95. This means that if enough time has elapsed for the complete exchange of water between the two reservoirs, then 95% of the phosphorus that enters the surface box is removed in particulate form. Detailed studies of nutrient dynamics in the mixed layer indicate that the average atom is recycled 10 times before escaping as a sinking particle into the deep sea. 

For phosphorus,/ 0.01. This means that only 1% of the particle flux that enters the deep-water box during any given mixing cycle survives to become buried in the sediments. Ninety-nine percent is remineralized in the deepwater. 

Mixtures of chlorates with such materials must not be ground together with a postle and mortar. The materials should be ground separately, and then carefully mixed on paper with a feather. Phosphorus in contact with a chlorate may explode spontaneously. Thus if a drop of soln. of phosphorus in carbon disulphide be allowed to fall on a little potassium chlorate, a loud explosion occurs as soon as the carbon disulphide has evaporated. The red phosphorus in the mixture on the side of a box of safety matches gives a series of sparks when a crystal of potassium chlorate is rubbed thereon, and serious accidents have occurred as a result of the accidental rubbing of tabloids of potassium chlorate against the sides of a match-box in the pocket. 

Note that the reaction at the phosphorus atom is postulated to occur by an SN2 (no intermediate formed) rather than by an addition mechanism such as we encountered with carboxylic acid derivatives (Kirby and Warren, 1967). As we learned in Section 13.2, for attack at a saturated carbon atom, OH- is a better nucleophile than H20 by about a factor of 104 (Table 13.2). Toward phosphorus, which is a harder electrophilic center (see Box 13.1), however, the relative nucleophilicity increases dramatically. For triphenyl phosphate, for example, OH- is about 108 times stronger than H20 as a nucleophile (Barnard et al., 1961). Note that in the case of triphenyl phosphate, no substitution may occur at the carbon bound to the oxygen of the alcohol moiety, and therefore, neutral hydrolysis is much less important as compared to the other cases (see /NB values in Table 13.12). Consequently, the base-catalyzed reaction generally occurs at the phosphorus atom leading to the dissociation of the alcohol moiety that is the best leaving group (P-0 cleavage), as is illustrated by the reaction of parathion with OH ... 

Nonmetallic elements predominating in the ash are phosphorus (700 g in the human body), sulfur (175 g), and chlorine (105 g). Not only are these three elements essential to all living cells but also selenium, fluorine, silicon (Box 4-B), iodine, and boron are needed by higher animals and boron by plants (Fig. 1-17). Iodine deficiency may affect one billion human beings and may cause 20 million cases per year of cretinism, or less severe brain damage.158... 

This key enzyme of the nervous system is inactivated irreversibly by powerful phosphorus-containing poisons that had been developed as insecticides and as war gases (nerve gases, Box 12-C). Around 1949, the nerve gas diisopropylfluorophosphate (DFP) was shown also to inactivate chymotrypsin. When radioactive 32P-containing DFP was allowed to react the 32P became... 

Figure 20. Summary of phosphorus cycle in southern Lake Michigan. Values in boxes are areal concentrations (milligrams/square meter) values on arrows are fluxes (milligrams/square meter per year). Areal concentrations are based on the mean depth (85 m) of the water column.

When shells are loaded with certain high explosives which produce no smoke (such as amatol), smoke boxes are generally inserted in the charges in order that the artilleryman, by seeing the smoke, may be able to judge the position and success of his fire. These are cylindrical pasteboard boxes containing a mixture of arsenious oxide and red phosphorus, usually with a small amount of stearine or paraffin. 

The etherification of phosphorus chlorooxide with cresol is carried out in etherificator 5, a cast iron cylindrical apparatus lined with two layers of diabase tiles. The reactor is filled with a necessary amount of phosphorus chlorooxide from batch box 2 magnesium chloride is loaded through a hatch and dried cresol is loaded out of batch box 1. After the reactants have been loaded, the apparatus is heated to 80 °C. The reaction is started at this temperature, but then it is gradually raised to 170 °C. At 170 °C the mixture is held for about 5 hours after that, the acidity number is determined. When the acidity number is 30 mg KOH/g, the reaction is stopped. 

After phosphorisation the mixture is sent into settling box 10 to be separated from tarlike products and unreacted phosphorus pentasulfide then it is pumped into apparatus 11 to be neutralised with calcium hydroxide and dehydrated (at heating). The dehydrated mixture is sent to centrifuge 12, where bis(octylphenoxy)dithiophosphate is separated from mechanical impurities. 

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