Ethyl metaphosphate

Thus the reaction product of diethyl ether and diphosphorus pentoxide, a pale yellowish syrupy mass, was designated as ethyl metaphosphate (147), other ethoxy-containing compounds give the same product 102-103) it can be reprecipitated from chloroform/ether and reacts with aniline to give the phosphoramidate 148 104) which is conceivably a trapping product of ethyl metaphosphate 147, or a cleavage product of polymeric metaphosphates. 

It was demonstrated that the IR spectrum of the ethyl metaphosphate 147 accessible from the enol phosphate 146 is identical with that of the cyclic triethyl metaphosphate 149,05) synthesized by an independent route. 

During a search for high-energy phosphates, Ponnamperuma was able to synthesize adenosine triphosphate (ATP) from ADP, AMP or adenosine from ethyl metaphosphate in dilute aqueous solution under the influence of UV light. The role of the UV irradiation is unclear, as the phosphate itself is a high-energy species (Ponnamperuma et al., 1963). 

Miller and Parris (1964) pointed out that the preparation of ethyl metaphosphate from P2O5, diethyl ether and chloroform could hardly be considered "prebiotic this criticism is certainly irrefutable ... 

As early as 45 years ago, G. Schramm et al. (1962) carried out the synthesis of AMP, ADP and ATP using ethyl metaphosphate as the phosphorylating agent. These successful syntheses led to the formation of longer nucleotide chains however, they by no means correspond to the conditions present on the primordial Earth. Thus, the question as to the source of the phosphates remains paramount. According to Schwartz (1998), the following phosphate sources deserve consideration ... 

Esters of metaphosphoric acid are known. Ethyl metaphosphate, C2HsP03, was prepared by heating dry ethyl acetate with phosphoric oxide and extracting the product with ether and warm alcohol, from which the ester was precipitated by ether.4... 

Material initially prepared by Langheld and usually called ethyl metaphosphate was regarded by Ratz and Thilo as a mixture of the cyclic esters (2) and (3). A later study by Calvin el a . using NMR data indicated the probable presence of an additional cyclic ester and an open-chain ester. 

The factor most influential in determining the outcome of a condensation reaction is the catalyst. The catalysts most commonly employed are mineral acids, although copper(lI) sulfate, phosphorus pentaoxide, ethyl metaphosphate, cation-exchange resins in the acid form, and zinc chloride (alone - or in combination... 

Phosphoric acid esters Ethyl metaphosphate Poly phosphoric acid esters... 

A method in use commercially is to heat a phosphate triester with phosphorus pentoxide or thionyl chloride (5.308). The tetraethyl analogue of (5.308), that is, TEPP (5.309) is an effective insecticide (Chapter 12.12). It can be distilled at low pressure, but if impure, or at normal pressure, it disproportionates into triethyl phosphate and a non-volatile ethyl metaphosphate polymer (5.310). 

Phosphoric acid esters Ethyl metaphosphate Phosphate buffer Quinoline phosphate Dichloro phosphites, CH OPCh Triethyl phosphate. Butyl phosphate Phenyl acid phosphate Diphenyl hydrogen phosphate Di-p-nitrophenyl hydrogen phosphate (RO)gPS... 

Ethyl metaphosphate Quinoline phosphate Dichlorophosphites, CH2OPCI2... 

---