Methylphosphonic acids

Methylphosphonic acid [993-13-5] M 96.0, m 104-106 , 105-107 , 108 , pK, 2.12, pK j 7.29. If it tests for Cf, add H2O and evaporate to dryness repeat several times till free from Cl". The residue solidifies to a wax-like solid. Alternatively, dissolve the acid in the minimum volume of H2O, add charcoal, warm, filter and evaporate to dryness in a vacuum over P2O5. [J Am Chem Soc 75 3379 1953.] The di-Na salt is prepared from 24g of acid in 50mL of dry EtOH and a solution of 23g Na dissolved in 400mL EtOH is added. A white ppte is formed but the mixture is refluxed for 30min to complete the reaction. Filter off and recrystallise from 50% EtOH. Dry crystals in a vacuum desiccator. [7 Chem Soc 3292 1952.]... 

Although most of the macrocycles that contain phosphorus or arsenic which have thus far been prepared, are primarily transition metals binders, two compounds have been prepared which are essentially crown ethers containing phosphorus. Kudrya, Shtepanek and Kirsanovhave prepared two compounds which are essentially polyoxygen macrocycles but which contain one or two methylphosphonic acid esters as part of the ring. These two macrocycles are shown below as 7d and 17 and are both prepared by the reaction of 2,2 [oxybis(ethyleneoxy)] bisphenolate with methylphosphonic dichloride in a mixture of acetonitrile and benzene. The crystalline monomer 16) and dimer 17) were isolated in 17% and 11% yields respectively as indicated in Eq. (6.13). 

Hydrolysis products GF s hydrolysis products, hydrofluoric and cyclohexyl-methylphosphonic acids, are less toxic than their parent compound. 

Reactivity Hydrolysis products Ethyl methylphosphonic acid, 2-(Diethylamino) ethanethiol, and P,P-diethyl dimethyldiphosphonate... 

Hydrolysis products Hydrolyzes to give toxic products, MF and HF. Further hydrolysis of MF results in methylphosphonic acid. 

Diisopropyl methylphosphonate is rapidly absorbed following oral administration in animals and is widely distributed throughout the body. Two metabolites of diisopropyl methylphosphonate are isopropyl methylphosphonic acid (IMPA) and methylphosphonic acid (MPA). Excretion of these metabolites in animals occurs primarily through the urine. 

EPA. 1992. Health advisory for isopropyl methylphosphonic acid (IMPA). U.S. Environmental Protection Agency, Office of the Assistant Administrator for Water. NTIS No. PB92-232149. 

Hoskin FCG. 1956. Some observations concerning the biochemical inertness of methyl phosphonic and isopropyl methylphosphonic acids. Can J Biochem Physiol 34 743-746. 

Purdon JG, Pagotto JG, Miller RK. 1989. Preparation, stability, and quantitative analysis by gas chromatography and gas chromatography-electron impact mass spectrometry of tert-butyldimethylsilyl derivatives of some alkylphosphonic and alkyl methylphosphonic acids. J Chromatogr 475 261-272. 

Reactions and Properties of Phosphonic and Phosphinic Acids and their Derivatives.-A free radical mechanism has been proposed to account for the cleavage of the phosphorus-carbon bond in the alkylphosphonic acids (155) by E coli to give a mixture of alkane (methane only, from methylphosphonic acid) and terminal alkene. 

Phosphonic acid analogues of aspartic acid, glutamicacid C-benzy1g1ycine,191 and the phosphor inane (70)1 92 have been studied, also the oxime (71)193 a phosphonopiperidinol - with a very distorted chair structure,194 the phosphonate (72),195 a pyrazole,196 a thiocarbamoy1phosphonate, 97 and two iminobis-(methylphosphonic acids).198 Additionally there have been studies of the new bicyclic sulphur heterocycle (73),199 the oxazaphospho1idine (74)200 and a triaminophosphetanium aluminium betaine.201... 

The superior coordinating capacity of phosphonate over carboxylate is illustrated in the 9Be NMR spectra in Fig. 25 (260). The similarity of the spectra obtained by reaction of BeS04 and methylphosphonic acid or phosphonacetic acid indicates that the carboxylate group is not bound to the beryllium under these experimental conditions. It should be noted that substitution of a water molecule by a phosphonate ligand causes the 9Be resonance to move upfield when it co-ordinates, as does the fluoride ion (271), the only other monodenate ligand... 

The ester group is then hydrolysed, and the hydrolysis normally stops at the MePO(OH)2 stage. More vigorous conditions are required to rupture the Me—P bond. Thus the normal hydrolysis product of D.F.P. and of tabun, namely, phosphoric acid, will give a positive test with ammonium molybdate, whereas the product from sarin, namely, methylphosphonic acid, will not respond to this test. Vigorous reagents such as hot nitric acid and ammonium persulphate will break the C—P link and then a positive test for phosphate is obtained with ammonium molybdate. Sarin can be prepared in a variety of ways. Three... 

Sarin, which is hydrolysed only to methylphosphonic acid, will not give this colour. If, however, the sarin is first volatilized into ammonium persulphate, and then heated, rupture of the C—P bond takes place at an appreciable rate, and a positive reaction is then usually given. 

Nucleophilic Reactions.—Attack on Saturated Carbon. Selected examples of the Arbusov reaction include phosphorylation of the chloroacetophenones (1) to give phosphonates, which cyclized to (2) in the presence of acid chlorides,1 formation of the azodiphosphonate (3) from 2,2 -dichloro-2,2 -azopropane,2 3 and the reaction of 2-chloro-3,4-dihydro-3-oxo-2//-l,4-benzothiazine (4) with triethyl phosphite to give the 2-phosphonate (5), which is used as an olefin synthon.8 Bis(trimethylsilyl) trimethylsiloxymethylphosphonite (6) has been synthesized by silylation of hydroxy-methylphosphonous acid, and, as expected, undergoes a normal Arbusov reaction with alkyl halides to give the phosphonates (7).4 This series of reactions, followed by... 

M M2 8 MACT MAV MDB MDM MEO MPA MPa MPT MSB molar concentration energetic material used for propulsion of certain assembled chemical weapons maximum achievable control technology modified ammunition van munitions demilitarization building munitions demilitarization machine mediated electrochemical oxidation methylphosphonic acid megapascals metal parts treater munitions storage building... 

ToF-SIMS, and AFM results, the formation of ordered monolayers of octade-cylphosphoric acid on a Ta205 surface involves both monodentate and bi-dentate phosphate species [135]. In the case of goethite, (y-AlOOH), it was found that methylphosphonic acid bound to the surface as a monodentate or a bidentate species depending on the pH and the concentration [163]. 

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