Dialkyl phosphate ester

Mixtures of a titanium complex of saturated diols, such as TYZOR OGT, and a titanium acylate, such as bis- -butyl-bis-caproic acid titanate, do not have a yellowing or discoloring effect on white inks used to print polyolefin surfaces (506). The complexes formed by the reaction of one or two moles of diethyl citrate with TYZOR TPT have an insignificant color on their own and do not generate color with phenol-based antioxidants (507). The complexes formed by the addition of a mixture of mono- and dialkyl phosphate esters to TYZOR TBT are also low color-generating, adhesion-promoting additives for use in printing polyolefin films (508). 

In addition to their poor solubility in water, alkyl phosphate esters and dialkyl phosphate esters are further characterized by sensitivity to water hardness [37]. A review of the preparation, properties, and uses of surface-active anionic phosphate esters prepared by the reactions of alcohols or ethoxylates with tetra-phosphoric acid or P4O10 is given in Ref. 3. The surfactant properties of alkyl phosphates have been investigated [18,186-188]. The critical micelle concentration (CMC) of the monoalkyl ester salts is only moderate see Table 6 ... 

It was found that the rate of attack of hydroxide on the phosphorus of dialkyl phosphate esters is far slower than previously estimated. Consequently, nucleases are considerably more proficient than previously suggested. ... 

In contrast, alkynyl dialkyl phosphate esters, 78, are formed in good isolated yields by either the treatment of alkynyliodonium triflates with (R0)2P02Na or the reaction of terminal alkynes with [hydroxy(phosphoryloxy)iodo]benzene, 77 [Eq. (34)], or the sequential treatment of alkynylsilanes with PhIO Et20Bp3 followed by aqueous (R0)2P02Na [Eq. (35)) [61]. These new, alkynyliodonium-derived, acetylenic esters have potent biological activity [4] in particular, the alkynyl benzoates are protease inhibitors [62], whereas the alkynyl dialkylphos-phates, 78, are inhibitors of a bacterial phosphotriesterase [63]. 

For the preparation of multiply phosphorus bridged systems, we studied the pyrolytic behavior of calixarene dialkyl phosphate ester derivatives. These compounds are useful intermediates for the OH-depletion of the calixarenes [15, 16] and for the preparation of aminocalixarenes [17]. These esters can be prepared by treatment of the calixarenes with a dialkyl chlorophosphate in the presence of base [18]. In the case of 1, under mild conditions, the distal (i.e, 1,3-) bis(diethyl phosphate ester) derivative is obtained (2a) while under more drastic conditions (CH2Cl2/aq NaOH, phase transfer catalysis) the tetraphosphate 2b is formed [15a]. Calixarene mono diisopropyl phosphate ester and l,2-bis(diisopropyl phosphate ester) derivatives (2c and 2d) were prepared by mono- or dideprotonation by LDA of the monospirodienone derivative 3 followed by treatment with the corresponding dialkyl chlorophosphate [15e, 17b]. Aromatization of the spirodienone products was achieved by heating or by their treatment with HBr yielding the dialkylphos-phate esters derivatives 2c and 2d [15e, 17b]. 

Multiply bridged calixaienes can be easily obtained by pyrolysis of calixarene (dialkyl phosphate ester) derivatives. The multiple bridging of the calix[4]- and calix[6]arenes raises the barrier for ring inversion, but it does not completely freeze all possible dynamic processes. 

While 3rd-order dependence of Ki on the extractant (consistent with formation of Ln(HA2)3 species in the organic phase) is the rule with dialkyl phosphate esters in most solvents, there is considerable evidence that the organic phase species may be LnA(HA2)2 in some solvents and with aromatic diesters of phosphoric acid. By no means can the solvent used for dilution be considered inert. Extractions are definitely lower in those diluents which can interact with the extraction agent. 

Inefficiencies ia the reaction with POCl leads to alternative production of trialkyl phosphates by employing the sodium alkoxide rather than the alkyl alcohol itself Dialkyl aryl phosphates are produced ia two steps. The low molecular weight alcohol iavolved (eg, butyl) first reacts with excess POCl. The neutral phosphate ester is then completed by the iatermediate chloridate reacting with excess sodium arylate ia water. 

Phosphated and Polyphosphated Alcohols In most cases aliphatic alcohols with a chain length in the range of 10-20 carbon atoms are converted with phosphorus pentoxide. A mixture of alkyl dihydrogen esters (primary) and dialkyl hydrogen esters (secondary) are yielded. 

The preparation of phosphate esters has been reviewed and full details have appeared of the use of 2-chloromethyl-4-nitrophenyl esters (reported last year) in the synthesis of monoesters and mixed dialkyl esters of phosphoric acid. 

There are also examples in which phosphate esters of saturated alcohols are reductively deoxygenated.229 Mechanistic studies of the cleavage of aryl dialkyl phosphates have indicated that the crucial C-O bond cleavage occurs after transfer of two electrons.230... 

Phosphorus is a common component of additives and appears most commonly as a zinc dialkyl dithiophosphate or triaryl phosphate ester, but other forms also occur. Two wet chemical methods are available, one of which (ASTM D1091) describes an oxidation procedure that converts phosphorus to aqueous orthophosphate anion. This is then determined by mass as magnesium pyrophosphate or photochemically as molybdivanadophosphoric acid. In an alternative test (ASTM D4047), samples are oxidized to phosphate with zinc oxide, dissolved in acid, precipitated as quinoline phosphomolybdate, treated with excess standard alkali, and back-titrated with standard acid. Both of these methods are used primarily for referee samples. Phosphorus is most commonly determined using x-ray fluorescence (ASTM D4927) or ICP (ASTM D4951). 

The use of trialkyl phosphates for dialkylation of anilines has been found applicable to naphthylamines and to a large number of anilines substituted in the ortho, meta, or para position by groups such as chloro, methoxy, and methyl and in the meta position by fluoroalkyl (author s laboratory). The reaction has been used to introduce ethyl and M-butyl as well as methyl groups by employing the appropriate phosphate esters. The reported yields range from 50% to 95%. 

The alkylating activity is dependent on the size of the alkyl group with the relative activity following the order methyl ethyl > propyl > butyl. Beyond butyl, the activity is greatly minimized. For alkyl esters of dibasic (e.g., sulfate) andtribasic (e.g., phosphate) acids, the alkylating activity is completely eliminated if any of the alkyl groups are hydrolyzed (e.g., monoalkyl sulfate or dialkyl phosphate) (Table 14.10). 

Since the resulting monoalkyl sulfate or dialkyl phosphate lacks alkylating activity, remove one of the alkyl groups from the esters of dibasic (e.g., sulfate) and tribasic (e.g., phosphate) acids. 

Sulfuric acid (or phosphoric acid) is preferred as an acid catalyst for addition of water to alkenes because the conjugate base, HSO40 (or H2P04e), is a poor nucleophile and does not interfere in the reaction. However, if the water concentration is kept low by using concentrated acid, addition occurs to give sulfate (or phosphate) esters. The esters formed with sulfuric acid are either alkyl acid sulfates R—0S03H or dialkyl sulfates (R0)2S02. In fact, this is one of the major routes used in the commercial production of ethanol and... 

Peracids can also be prepared from reaction of hydrogen peroxide with acyl halides, anhydrides, amides, dialkyl phosphates, N-acylimidazoles, aromatic aldehydes, lipase catalysis and esters (Figure 2.38).100-107... 

Phosphate esters are prepared by the partial esterification of fatty alcohol with phosphorous oxychloride followed by hydrolysis (20). This method yields a product that is a mixture of monoalkyl, dialkyl, and trialkyl phosphates. 

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. 

Phosphate esters show important thermal susceptibility (Fig. 1). Dialkyl phosphates, such as those found in nucleic acids (Fig. 2), decompose with the initial loss of one alkyl group, the concomitant transfer of protons, followed by the elimination of the second alkyl group and the subsequent loss of water. This thermal instability of phosphoesters has been used in the analysis of nucleic acids. Thus the pyrolysis that usually precedes the recording of a mass spectrum permits cleavage of the polymeric phosphoesters (nucleic acids), followed by phosphate extrusions, producing nucleotides or simple nucleosides as fragment ions. 

Synthesis of Phosphoric Acids and their Derivatives. - Among various approaches to phosphate esters the phosphorylation of phenols with dialkyl cyanophosphonate and the synthesis of triaryl phosphates under phase-transfer conditions are worthy of mention. Mixed trialkyl phosphates are also reported to be formed by brief cathodic electrolysis of the reaction of dialkyl phosphonates with aromatic aldehydes and ketones, presumably by rearrangement of the initial a-hydroxy compounds. Further reports have appeared of the generation of metaphosphates by various methods. The synthesis of analogues 1 of famesyl pyrophosphate which incorporate photoactive esters has been reported both compounds are competitive inhibitors of farnesyl transferase. 

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