Monoalkyl phosphates

Phosphoric acid, monoalkyl phosphates, and phosphonic acids, but not dialkyl phosphates (107), can be aminoalkylated on the oxygen (108—110). 

Monoalkyl phosphate extractants exhibit good efficiency in the presence of dilute nitrate, sulfate, or chloride, and cause fewer phase-separation... 

The development of monoalkyl phosphate as a low-skin-irritating anionic surfactant is accented in a review with 30 references on monoalkyl phosphate salts, including surface-active properties, cutaneous effects, and applications to paste- and liquid-type skin cleansers, and also on phosphorylation reactions from the viewpoint of industrial production [26]. The preparation and industrial applications of phosphate esters as anionic surfactants were discussed [27]. 

The development of monoalkyl phosphate as a low skin irritating anionic surfactant is accented in a review with 30 references on monoalkyl phosphate salts, including surface-active properties, cutaneous effects, and applications to paste and liquid-type skin cleansers, and also phosphorylation reactions from the viewpoint of industrial production [26]. Amine salts of acrylate ester polymers, which are physiologically acceptable and useful as surfactants, are prepared by transesterification of alkyl acrylate polymers with 4-morpholinethanol or the alkanolamines and fatty alcohols or alkoxylated alkylphenols, and neutralizing with carboxylic or phosphoric acid. The polymer salt was used as an emulsifying agent for oils and waxes [70]. Preparation of pharmaceutical liposomes with surfactants derived from phosphoric acid is described in [279]. Lipid bilayer vesicles comprise an anionic or zwitterionic surfactant which when dispersed in H20 at a temperature above the phase transition temperature is in a micellar phase and a second lipid which is a single-chain fatty acid, fatty acid ester, or fatty alcohol which is in an emulsion phase, and cholesterol or a derivative. 

Compound (1) phosphorylates phosphate monoesters and alcohols, although with the latter a considerable excess of alcohol is necessary to obtain satisfactory yields. In the absence of mercuric ions the milder phosphorylating species (3) can be isolated which converts monoalkyl phosphates to pyrophosphate diesters in good yield but does not react appreciably with alcohols unless catalytic amounts of boron trifluoride are added. Amine salts of (3) are converted to phosphoramidates on heating. In the presence of silver ions, O-esters of thiophosphoric acid behave as phosphorylating agents and a very mild and convenient procedure suitable for preparing labile unsymmetrical pyrophosphate diesters, such as the... 

C. Reactions.—The iV-chloroquinonimine (50) reacts with monoalkyl phosphates in dry pyridine to give symmetrical pyrophosphate esters. If present in excess it can react further, giving an intermediate which is attacked by alcohols or water with cleavage of the pyrophosphate bond. 

As is apparent from Fig. 1, the dianions of monoalkyl phosphates normally resist hydrolysis. However, for leaving groups whose conjugate acids exhibit a pKa < 5 in water, hydrolysis of the dianion becomes faster than that of the monoanion. Fig. 2 shows a pH profile characteristic of this situation. Whereas the hydrolysis rate of 2,4,6-trichlorophenyl phosphate (pKa of the phenol 6.1) still shows the typical monoanion preference as seen for methyl phosphates (Fig. 1), the dianion of 2,4-dinitrophenyl phosphate (pKa of the phenol 4.09) is hydrolyzed far faster than the monoanion 2-chloro-4-nitrophenyl phosphate represents an intermediate case (pKa of the phenol 5.45)6S). 

Monoacylglycerols, 10 802, 804, 822 Monoalkanolamine titanates, 25 95 Monoalkoxytriacyl titanates, 25 129 Monoalkylamines, 13 105 Monoalkylboranes, 13 632, 633, 635 Monoalkylhydrazines, 13 571 Monoalkyl phosphate extractants,... 

The catalysed two-phase adaptation of the Atherton-Todd procedure is effective for the phosphorylation of primary alcohols and of phenols [6] to produce trialkyl phosphates and dialkyl aryl phosphates. Trialkyl phosphates have also be obtained in high yield (>75%) from the alkylation of preformed tctra-n-butylammonium di-/-butylphosphate [7], Subsequent cleavage of the /-butyl groups provide a simple synthesis of monoalkyl phosphates. 

Reemtsma T, Lingott J, Roegler S (2011) Determination of 14 monoalkyl phosphates, dialkyl phosphates and dialkyl thiophosphates by LC-MS/MS in human urinary samples. Sci Total Environ 409 1990-1993... 

The hydrolysis of a monoalkyl phosphate may also be classed as a dephosphonylation reaction, that is, one involving removal of the O-phosphono [(HO)gP(O)-] group.259... 

In contrast to the chemistry of extraction of uranium(VI) by organophosphorus acids, that of uranium(IV) has not been widely studied. It is known,135 however, that the extraction of U4+ by mono(2-ethylhexyl)phosphoric acid (2-ethylhexyl dihydrogen phosphate), for example, exceeds that of U022+ by a factor of 105. This clearly provides the basis for the strong extraction of uranium(IV) from phosphoric acid solutions by extractants containing monoalkyl phosphates. The existence of a synergistic effect in the extraction of uranium(IV) by mixtures of mono(2-ethylhexyl)phosphoric acid and neutral organophosphorus compounds was also reported recently.136... 

Phosphorylation of alkyl bromides. Alkyl bromides react with 1 in refluxing DME to form an alkyl di-f-butyl phosphate, which is converted by TFA in benzene to a monoalkyl phosphate, usually isolated as the anilinium salt. ... 

Other Specialty Surfactants. Monoalkyl phosphate, fatty alcohol ether phosphate, and fatty alcohol sulfosuccinate are some of the specialty surfactants derived from fatty alcohol with specific applications in the cosmetics and other chemical industries. 

Monoalkyl phosphate and phosphate esters are special types of phosphoms-contain-ing anionic surfactants that are of great industrial importance. They are used for flameproofing, as antistatic for textiles, for foam inhibition, as an extreme pressure (EP) lubricant additive, as a surfactant component for alkaline, and as acid cleaners and for special cosmetic preparations (5). The commercially available phosphate ester products are complex mixtures of monoester and diester, free phosphoric acid, and free nonionic. 

The resulting product is a mixture of dialkyl and monoalkyl phosphate esters. These products also contain small amounts of condensed phosphates and phosphoric acid. Neutralization of the acids with bases like alkali hydroxides, ammonia, or amines produces water-soluble anionic surfactants and emulsifiers. 

Monoalkyl phosphates inhibit the foam generation of other anionic and nonionic surfactants. The composition of the phosphate ester greatly affects the functional properties of the product. 

As the acidity of the solution is increased, the rate of hydrolysis of monoalkyl phosphates, ROPO(OH>2, rises from essentially zero in alkaline solution, and passes through a maximum at the point (moderate acidity, pH about 4) where the concentration of monoanion, R0P0(0H)(0 ), is greatest. Cleavage is at the phosphorus-oxygen bond. 

The mechanism of U02 " extraction by monoalkyl phosphoric acid reagents appears to be a more complex process than for their dialkyl counterparts. This results from the polymerization of the monoalkyl phosphate in the organic phase and the hydration of the extracted uranyl species so that variable stoichiometries arise for the extractant/water/UO complex. The extraction of from sulfuric acid by mono-2,6,8-trimethylnonyl phosphoric acid (H2DDP) and mono-n-butyl phosphoric acid (H2MBP) as 0.05 M solutions in benzene was shown to follow equations (61) and (62) when an excess of extractant was present. When an excess of uranium was present, equations (63) and (64) applied where n, x, y and z were variable numbers which depended upon the extent of extractant polymerization and hydration of the extracted species. Synergistic effects may also be found with the monoalkyl phosphoric acid extractants and in one recent example the use of tri-n-octylphosphine ocxide (TOPO) as a synergist with H2MEHP allowed the extraction of U02 from phosphoric acid solutions. The uranium may be returned to the aqueous phase by contact with concentrated acid, which reverses the extraction process by protonation of the phosphate. 

Surfactants used in the polymerization are water-soluble, halogenated surfactants. They are in particular fluorinated surfactant such as ammonium, substituted ammonium, quarternary ammonium, or alkali metal salts of perfluorinated or partially fluorinated alkyl carboxylates, monoalkyl phosphate esters, alkyl ether or polyether carboxylates, alkyl sulfonates, and alkyl sulfates. 

Bjelopavlic, M., Ralston, J., and Reynolds, G., Adsorption of monoalkyl phosphates at the zircon-aqueous solution interface, J. Colloid Interf. Sci., 208, 183, 1998. 

Other classes of substances tested as potential chiral carriers in SLMs are dialkyl and monoalkyl phosphates, phosphonates, and phosphinates based on (—)-menthol and (—)-nopol [43]. The amino acids are transported... 

Thomas, Gomes Colgate-Palmolive Light-duty liquid cleaning compositions containing monoalkyl phosphate ester Enhanced mildness to the human skin... 

Monoalkyl phosphate having a 3-branched alkyl group... 

The nonoxyethylenated monoalkyl phosphates cause little skin irritation and are used in personal care products. The sodium salt of monododecyl phosphate, unlike soap, works in a weakly acidic medium and can therefore be used as a detergent in face cleaners and cleansers and in body shampoos. The potassium or alkanol-ammonium salt of monohexadecyl phosphate is used as an emulsifying agent in skin care products. The dialkyl phosphate must be avoided in the synthesis of these products, since it reduces foaming and water solubility. 

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