Alkyl phosphonic acid

Multilayers of Diphosphates. One way to find surface reactions that may lead to the formation of SAMs is to look for reactions that result in an insoluble salt. This is the case for phosphate monolayers, based on their highly insoluble salts with tetravalent transition metal ions. In these salts, the phosphates form layer stmctures, one OH group sticking to either side. Thus, replacing the OH with an alkyl chain to form the alkyl phosphonic acid was expected to result in a bilayer stmcture with alkyl chains extending from both sides of the metal phosphate sheet (335). When zirconium (TV) is used the distance between next neighbor alkyl chains is - 0.53 nm, which forces either chain disorder or chain tilt so that VDW attractive interactions can be reestablished. 

Most common is the preparation of alkyl phosphonic acid esters (phospho-nates) 4 (Z,Z = OR) from phosphorous acid esters (phosphites) 1 (Z,Z = OR). The preparation of phosphinic acid esters (Z = R, Z = OR) from phosphonous acid esters, as well as phosphine oxides (Z,Z = R) from phosphinous acid esters is also possible. 

Other cyclizations at phosphorus have been observed when certain phosphinates were used in the acid-catalyzed Mannich reaction. As observed previously with various phosphonous acid derivatives, reaction of aliphatic phosphinic acids with primary amines favored the formation of 2 1 adducts (73). Thus, glycine and other a-amino acids reacted under the typical conditions with excess formaldehyde and alkyl phosphonous acids to give the bis-phosphinylmethyl adducts 125. 

Fluorapatite is the only significant phosphorus-containing mineral in the Earth s crust and schreibersite has been found in iron meteorites. The only organic species to be found containing phosphorus in meteorites are the alkyl phosphonic acids. These are at least promising even if they do not contain the P-O-P phosphoester bond unit. 

The reason for such a behaviour of arsenic acid is that arsenic is a member of the group 5A elements in the periodic table. Phosphorus and antimony are also group 5 elements and are known to be chemically similar to arsenic. On this basis [8,9], the antimonic acids were found to be poor cassiterite collectors. The alkyl phosphonic acids were not selective collectors. The ethylphenylene phosphonic acid was found to produce similar or better results compared to /7-tolyl arsonic acid. The structural formula for phosphonic acid (Figure 21.5) is similar to that of /7-tolyl arsonic acid but arsenic was replaced with phosphoms. The styrene phosphonic acid radicals are C6H5-CH-CH and p-ethylphenylene CH3-CH2-C6H4. 

Fluorinated phosphinic and phosphonic acid derivatives Perfluoro derivatives of alkyl phosphonic acid CnF2n+1-P(0)(0H)2 and alkyl phosphinic acid CnF2n+i(CmF2m+1)-P(0)0H (n = m or n m) shown with their general structural formulae in Fig. 2.11.29(1) and (II) were examined by negative ESI- and APCI-FIA-MS. These anionic surfactant compounds contained perfluoro alkyl chains [2,22,25]. By analogy with their behaviour in the TSI-FIA-MS(—) process [25], the phosphonic acid formed [M — H] ions at m/z 399 and 499... 

Fig. 2.11.30. ESI—FIA—MS(— ) overview spectrum of a mixture of perfluoro derivatives of alkyl phosphonic acid (CnF2n+i-P(0)(OH)2) and alkyl phosphinic acid (CnF2n+i...

Cooper, G. W., Onwo, W. M., and Cronin, J. R. (1992). Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite. Geochim. cosmochim. acta, 56,... 

A solvent blank is used to eliminate the possibility of contamination arising from outside the sample, for example, from the syringe or from the instrument. It is recommended to use the sample solvent as solvent blank and run this test at the beginning and at the end of each sample series and whenever contamination is suspected. The memory effect is possible, for example, in the analysis of alkyl phosphonic acids. If the derivatization of these chemicals has not been complete, the nonderivatized acids are adsorbed on the injector liner. A silylation reagent may in such case react in situ with the adsorbed acids in the liner yielding false positive results. 

Cooper et al. (1992, 1997) identified a homologous series of C1-C4 alkyl phosphonic acids and alkanesulfonic acids in water extracts from Murchison. Isomeric diversity was apparent with five of the eight possible C1-C4 alkyl phosphonic and seven of the eight C1-C4 alkanesulfonic acids identified. The relative abundances of both classes of compound decreased exponentially with increasing carbon number. 

Popova, Z.V., Yanovskii, D.M., Kii pichnikov, P.A., Kapustina, A.S., and Davydova, V.M., Stabilization of polyvinyl chloride by alkyl phosphonic acid esters, Zh. Prikl. Khim. (Leningrad), 36, 187, 1963 J. Appl. Chem. USSR (Engl. Transl.), 36, 173, 1963. 

The carboxyphosphonates are the oldest and the most popular functionalized phosphonates. They are precursors of several reagents often used in organic synthesis such as diethyl l-(hydroxycar-bonyl)rncthy I phosphonate, dialkyl l-(alkoxycarbonyl)viny Iphosphonates, and dialkyl 1 -(alkoxycar-bony I)-1 -diazomethylphosphonates. The are known for their valuable role in organic synthesis and in the recent development of the chemistry of Foscamet and (o-amino-co-(hydroxycarbonyl)alkyl-phosphonic acids. This chapter deals with their preparations and transformations. 

General method for preparation of diphenyl esters of Gong-chain alkyl)phosphonic acids Equivalent amounts of the alcohol and triphenyl phosphite, together with 10 moles-% of sodium iodide, are placed in a flaskfitted with a thermometer, gas-inlet tube, stirrer, and distillation head water at about 50° is circulated through the attached condenser to prevent crystallization of the phenol. Nitrogen is led into the flask while the mixture is heated at the required temperature by a radiant heater until no more phenol distils (about 20 h). The remaining material is distilled at < 0.05 mm and the distillate is taken up in ether. The ethereal solution is washed with 2N-sodium hydroxide solution, dried and evaporated, and the residue is redistilled. 

Hydrocarbons, dialkyl alkyl-phosphonates, alkyl alkyl-phosphonic acids... 

The oxime from (4-chloro-l-oxobutyl)phosphonic acid has been cyclized to Pro ". An unusual rearrangement based on valence expansion of phosphorus is of interest the treatment of an (oxoalkyl)phosphonic oxime with Ph2PCl initially yields the phosphorus(III) derivative, but this rearranges spontaneously to give a phosphinic amide derivative 300, reduction of which then affords the [(V-diphenylphosphinoylamino)alkyl]phosphonic acid, readily hydrolysable under acid conditions to the free (aminoalkyl)phosphonic diester (Scheme 34)" ". 

Although this group of compounds is, as yet, very poorly represented, at least three routes for their synthesis already exist. The reactions between acethydroximic acids and (haloalkyl)phosphonic diesters yield the O-derivatives 372, from which selective work-up steps (Scheme 53) lead to the esters 373 or to the free [(aminooxy)alkyl]phosphonic acids 37 580 conventional approach consists in the reaction between a (1-hydroxyalky 1)-phosphonic or -phosphinic diester with A-hydroxyphthalimide in the presence of diethyl azodicarboxylate and PhjP under Mitsunobu conditions the resultant [l-(phthal-imidooxy)alkyl] acicl diesters lose the phthalimido group on hydrazinolysis, and a final aci-dolysis provides the [l-(aminooxy)alkyl]-phosphonic or -phosphinic acids. 

The role of silylated reagents in the formation of oligopeptides has been explored . Here, the bis(trimethylsilyl) ester of the [l-(trimethylsilylamino)alkyl]phosphonic acid is coupled with an activated A -cbz-amino acid and the silyl groups are subsequently removed under aqueous conditions the process can then be repeated. Oligopeptides have also been obtained as the result of enzyme catalysis when the condensations between amino carboxylic esters and (a) A -protected (aminoalkyl)phosphonic esters or (b) A -protected [(aminoalkyl)methyl]phosphinic esters is brought about in the presence of (a) alkaline phosphatase (Ej) and phosphodiesterase (E2) and (b) alkaline phosphatase and total bee venom (E3) (the latter aiding in the removal of both carboxylate ester and A -acetyl groups) ... 

Diphenylmethyl esters of A-protected [a-amino(alkyl)]phosphonic acids, conveniently obtainable from the acid and diphenyldiazomethane, may be hydrogenolysed without loss of A-protecting group (benzyloxycarbonyl, t-butoxycarbonyl, or phthalyl). ... 

For this reason, we consider it hardly possible to cite all of the publications. Let us focus only on the following examples. Hydroxamic acids have already been for a long time subject of the classical analytical chemistry. In [71], the possibility of using these compounds in flotation of rare-earth minerals is shown. It has been concluded that on a mineral surface cerium chelates are formed. Besides, chemisorption is accompanied by a physical multilayer adsorption of hydroxamic acid derivatives formed by reaction with cations in the water phase. A number of chelate-forming compounds including hydroxamic acids has been tested in flotation of niobium ores [72]. The best results are obtained when using alkyl phosphonic acids. Chemisorption mechanism and the structure of the surface compounds are established by spectroscopic methods. 

This reaction provides a convenient method for preparing alkyl phosphonic chloride, which is an important intermediate for alkyl phosphonic acid and corresponding esters. 

Far below stoichiometric amounts of sequestrants, precipitation of insoluble salts from water hardness can be avoided by the so-called threshold effect, in which formation of crystal nucleation sites is hindered by sequestrants. This process has been used for a long time to prepare feeding water for boilers e.g. steam vessels in rail way engines. Sodium pyrophosphate was originally used for this task. However, in particular alkyl phosphonic acids and their derivatives have a superior effect when compared to sodium pyrophosphate. 

---