Phosphates alkyl

Alcohols react with phosphoric acid to yield alkyl phosphates  

Esters of phosphoric acids are important in biochemical reactions. Especially important are triphosphate esters. Although hydrolysis of the ester group or of one of the anhydride linkages of an alkyl triphosphate is exothermic, these reactions occur very slowly in aqueous solutions. Near pH 7, these 

Enzymes, on the other hand, are able to catalyze reactions of these triphosphates in which the energy made available when their anhydride linkages break helps the cell make 

Alcohols can dehydrate to form alkenes. We studied this in Sections 7.7 and 7.8. Primary alcohols can also dehydrate to form ethers  

Dehydration to an ether usually takes place at a lower temperature than dehydration to the alkene, and dehydration to the ether can be aided by distilling the ether as it is formed. Diethyl ether is made commercially by dehydration of ethanol. Diethyl ether is the predominant product at 140°C ethene is the major product at 180°C  

A phosphonic acid can be esterifled with CH2N2 in 88-100% yield.  

(PhO)2P(0)Cl, 2 mol % TiCU, EtsN, THF, 1 h, 90-98% yield. This is a general method for phosphate formation of a variety of alcohols. (f-BuO)4Ti is also an effective catalyst.  

2-Mercaptohenzothiazole, A-methylpyrrolidone, DIPEA. The reagent has the advantage that it is odorless and does not lead to internucleotide cleavage, hut the cleavage rate is 10 times slower than when thiophenol is used.  

Thiophenol, TEA, DME or dioxane. In the case of dimethyl phosphonates this method can he used to remove selectively only one methyl group. Lithium thiophenoxide is also effective. 2-Methyl-5-f-hutylthiophenol is an odorless replacement for thiophenol.  

This odorless and easily prepared reagent is relatively 

---

Alkyl phosphates. From phosphorus oxychloride and the alcohol in the presence of p3u-idine, for example ... 

The above is a general procedure for preparing trialkyl orthophosphates. Similar yields are obtained for trimethyl phosphate, b.p. 62°/5 mm. triethyl phosphate, b.p. 75-5°/5 mm. tri-n-propyl phosphate, b.p. 107-5°/5 mm. tri-Mo-propyl phosphate, b.p. 83-5°/5 mm. tri-wo-butyl phosphate, b.p. 117°/5-5 mm. and tri- -amyl phosphate, b.p. 167-5°/5 mm. The alkyl phosphates are excellent alkylating agents for primary aromatic amines (see Section IV,41) they can also be ua for alkylating phenols (compare Sections IV,104-105). Trimethyl phosphate also finds application as a methylating agent for aliphatie alcohols (compare Section 111,58). 

Some esters of inorganic acids such as dimethyl sulfate are used as reagents m syn thetic organic chemistry Certain naturally occurring alkyl phosphates play an important role m biological processes... 

Garbodiimide Formation. Carbodiimide formation has commercial significance in the manufacture of Hquid MDI. Heating of MDI in the presence of catalytic amounts of phosphine oxides or alkyl phosphates leads to partial conversion of isocyanate into carbodiimide (95). The carbodiimide (39) species reacts with excess isocyanate to form a 2 + 2cycloaddition product. The presence of this product in MDI leads to a melting point depression and thus a mixture which is Hquid at room temperature. 

Phosphate Esters. A variety of phosphate esters are used as synthetic lubricants, particularly because of their good fire resistance. They have the general formula OP(OR)2, where R may represent a variety of aryl or alkyl hydrocarbon groups containing four or more carbon atoms to give three broad classes triaryl, trialkyl, and aryl alkyl phosphates (37,38). 

For extraction of uranium from sulfate leach Hquors, alkyl phosphoric acids, alkyl phosphates, and secondary and tertiary alkyl amines are used in an inert diluent such as kerosene. The formation of a third phase is suppressed by addition of modifiers such as long-chain alcohols or neutral phosphate esters. Such compounds also increase the solubihty of the amine salt in the diluent and improve phase separation. 

Another example of a cost-effective liquid-liquid extraction process is the one used for recoveiw of uranium from ore leach liquors (Fig. 15-3). In this case the solvents, alkyl phosphates in kerosine, are recovered by liquid-liquid extraclion using a strip solution, and the... 

TABLE 15-6 Settling of Aqueous Uranium Leach Liquors with Kerosine-Alkyl Phosphate Solvent ... 

Under similar conditions, perfluoroalkyl iodides react with alkyl phosphates to give fluorinated phosphine oxides, phosphinates, and phosphines [54 (equation 49) The product formed depends upon the stoichiometry and type of iodide used. When sodium alkyl trithiocarbonates are used as substrates, perfluoroalkyl tri-thiocarbonates ate formed [55]. 

Nucleophilic (8 2) reactions for the formation of benzyl, allyl, and certain alkyl phosphates [e.g., Me4N (R0)2P(0)0 and an alkyl halide in refluxing... 

Dimethyl sulfide, CH3SO3H. Methyl phosphates are selectively cleaved in the presence of other alkyl phosphates. ... 

Alkyl phosphates, preparation, 16, 9 Alkyl sulfides, preparation, 15, 72 JV-Alkyl- -toluidines, 18, 42 Allantoin, 13,1... 

Ether carboxylates are used not only in powdered detergents but in liquid laundry detergents for their hard water stability, lime soap dispersibility, and electrolyte stability they improve the suspension stability and rheology of the electrolyte builder [130,131]. Formulations based particularly on lauryl ether carboxylate + 4.5 EO combined with fatty acid salt and other anionic surfactants are described [132], sometimes in combination with quaternary compounds as softeners [133,163]. Ether carboxylates show improved cleaning properties as suds-controlling agents in formulations with ethoxylated alkylphenol or fatty alcohol, alkyl phosphate esters or alkoxylate phosphate esters, and water-soluble builders [134]. 

However, exclusive primary or secondary alkyl phosphates are seldom produced. That is due not only to the expenses of production but to the fact that in practical application the mixture of both esters combined with the rest of unreacted starting material often offers most interesting properties. Changing the molecular ratio of alcohol to P4O10 from 2 1 to 4 1 results in an increase of the secondary ester in the mixture from 35% to 65%. 

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 ... 

TABLE 6 Critical Micelle Concentration of Sodium Alkyl Phosphates... 

TABLE 8 Relative Foam Height of Sodium Alkyl Phosphates, Compared to Sodium Oleyl Sulfate in Distilled Water... 

Alkyl phosphates, alkylphenyl phosphates, and polyethoxyalkyl phosphates are stated to be good emulsifying agents. Ethoxylated phosphate esters in particular are used as emulsifiers in many cases. 

Salts of alkyl phosphates and types of other surfactants used as emulsifiers and dispersing agents in polymer dispersions are discussed with respect to the preparation of polymer dispersions for use in the manufactoring and finishing of textiles. Seven examples are presented to demonstrate the significance of surfactants on the properties, e.g., sedimentation, wetting behavior, hydrophilic characteristics, foaming behavior, metal adhesion, and viscosity, of polymer dispersions used in the textile industry [239]. 

For converting rust to clinging layers as a basis for coatings of paint and varnish, the addition of alkyl phosphates to phosphoric acid is suggested to improve its wettability and penetration [260]. 

Some phosphorus-containing surfactants have bacteriostatic properties. In combination with their physiological acceptance they are used in cosmetics and pharmaceuticals. In mutanase oral anticarie compositions the combination of alkyl phosphates and nonionic surfactants stabilizes mutanase. A dentifrice useful for prevention of dental caries contains 0.5% sodium lauryl phosphate and 1.5% polyoxyethylene (20) sorbitan monooleate [222]. 

The inhibition of Streptococcus mutans adherence to hydroxyapatite with combinations of alkyl phosphates and nonionic surfactants was tested. Seven alkyl phosphate derivatives and three nonionic surfactants were examined for their ability to inhibit the adherence of 3H-labeled cells of S. mutans to hydroxyapatite treated with buffer or parotid saliva. No compound by itself effectively hindered binding of bacteria to hydroxyapatite. A combination of certain of the alkyl phosphates, notably a disodium phosphate of 1-octadecanol, and nonionic surfactant at a 1 1 molar ratio gave a strong inhibition of S. mutans adherence. Treatment with this combination resulted in 98% reduction of adherence. Adsorption of the two types of surface-active agents alone and in combinations was studied using 14C-labeled agents. Electrophoretic measure-... 

Alkyl phosphates are also proposed as a humectant for printing pastes [14]. 

---