Phosphorns

FIGURE 3.10 (a) Electrostatic repnlsion between adjacent partial positive charges (on carbon and phosphorns, respectively) is relieved upon hydrolysis of the anhydride bonds of acetic anhydride and phosphoric anhydrides. The predominant form of pyrophosphate at pH values between 6.7 and 9.4 is shown, (b) The competing resonances of acetic anhydride and the simnltaneons resonance forms of the hydrolysis product, acetate. 

An ATP analog, /3, y-methylene-ATP, in which a —CHg— group replaces the oxygen atom between the /3- and y-phosphorns atoms, is a potent inhibitor of muscle contraction. At which step in the contraction cycle would you expect /3, y-methylene-ATP to block contraction ... 

Balazs G, Johnson BP, Scheer M (2003) Complexes with a Metal-Phosphorns Triple Bond. 

In addition there are certain other methods for the preparation such compounds. Upon heating of the thionocarbonate 2 with a trivalent phosphorus compound e.g. trimethyl phosphite, a -elimination reaction takes place to yield the olefin 3. A nncleophilic addition of the phosphorus to sulfur leads to the zwitterionic species 6, which is likely to react to the phosphorus ylide 7 via cyclization and subseqnent desnlfnrization. An alternative pathway for the formation of 7 via a 2-carbena-l,3-dioxolane 8 has been formnlated. From the ylide 7 the olefin 3 is formed stereospecifically by a concerted 1,3-dipolar cycloreversion (see 1,3-dipolar cycloaddition), together with the nnstable phosphorns componnd 9, which decomposes into carbon dioxide and R3P. The latter is finally obtained as R3PS ... 

Organophosphorus chemistry is complicated by the stability of P(V) species in addition to trivalent species snch as phosphines, and the possibility of tautomerism between them. In addition, many phosphorns componnds have been named as inorganics or biochemicals, as well as by the methods of organic nomenclature, leading to a proliferation of names. 

Many phosphorns (and arsenic) compounds are named using functional replacement nomen-clatnre in which replacement affixes are inserted into the names of the appropriate phosphorus... 

Example 14.4 A wastewater contains 10 mg/L of phosphorns expressed as P. The pH is 8.0. Assnme the wastewater contains 100 mg/L of alkalinity expressed... 

A plant is conducting phosphorns removal at a pH of 7.0. [sppo cJ is calcnlated to be 0.0126 mg/L as P and the nnit is operated at approximately an average temperature of 25°C. The dissolved solids content of the raw water is 140 mg/L, and the concentration of the calcinm ion is 130 mg/L. What is the precipitant nsed Calcnlate jca assnming that it cannot be determined from the given dissolved solids content of the raw water. 

A wastewater contains 10 mg/L of phosphorns expressed as P. The pH is 10.0. Assume the wastewater contains 100 mg/L of alkalinity expressed as CaCOs. The phosphorns is to be removed nsing ferric ferric chloride. If the wastewater flow is 0.75 mVsec, calcnlate the kilograms of solids produced per day. Assume the suspended solids content is 200 mg/L. 

The reaction of chlorine gas with solid phosphorus (P4) produces solid phosphorus pentachloride. When 16.0 g chlorine reacts with 23.0 g P4, which reactant limits the amonnt of phosphorns pentachloride prodnced Which reactant is in excess ... 

Reactions with Phosphorns(iii) Compounds.— The reaction of monochlorophosphines with secondary phosphine oxides generally gives diphosphine monoxides (49), except when R=CF8- Another exception is the case with R=t-butyl, when the phos-phinous anhydride (50 R=Bu ) is the stable product. The isomeric mono-oxide (49 R=Bu ) is formed when di-t-butylphosphine oxide reacts as its anion, but the product is readily isomerized. By contrast, the monoxide (49 R=Pr ) is stable. ... 

We can note that C N and C P ratios decrease. This may be related to the retention of nitrogen and phosphorns in microbial biomass, while carbon is lost as CO . The increase of C Ca and C K ratios indicate that Ca and K are lost more rapidly than carbon (Schlesinger, 1991). 

Krokhina, S.S., Pyrkin, R.L, Levin, Y.A., and Ivanov, B.E., Reaction of triethyl orthoformate with some trivalent phosphorns derivatives, Izv. Akad. Nauk SSSR, Ser Khim., 1420, 1968 Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.), 1349, 1968. 

The synthesis of dialkyl 3-cyanopropylphosphonates by Michael reaction can be effected by two different routes, the phosphorns reagent being the nucleophile or the Michael acceptor. The Michael addition of compounds containing active methylene groups such as cyanomethylphosphonate, ... 

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