Phosphate esters polyphosphoric acid

Fig. 9 Preparation of dextran phosphoric acid esters (phosphates) with polyphosphoric acid...

The earliest work on polyester synthesis used no catalyst or a simple acid catalyst such as p-toluenesulfonic acid, but use of weakly basic metallic salt catalysts is now almost universal. Many salts have been claimed to be useful in this context, but the best known examples are alkaline earth and transition metal acetates, tin compounds and titanium alkoxides [21-23]. Care must be exercised in selecting ester-interchange catalysts because some may cause degradation/ discoloration in the polymer during the subsequent polymerisation reaction [24], especially for PET and PEN. To prevent this occurrence, catalysts are often sequestered/complexed at the end of the ester-interchange phase by addition of phosphorus compounds such as phosphites, phosphates or polyphosphoric acid [25]. Titanium and tin compounds operate as catalysts for ester-interchange and polymerisation reactions, and in general do not require such procedures. 

In order to obtain anionic polyoxyethylene phosphate surfactants, either the terminal hydroxy group of a polyoxyethylated hydrophobic substance is reacted with a phosphorylating agent or a phosphate ester is oxalkylated. Most often aliphatic and aliphatic-aromatic alcohols are first treated with an alkylene oxide and afterward with one of the phosphorylating agents, such as P4OI0, POCl3, phosphoric acid, or polyphosphoric acid [39-48]. 

The resistance to hydrolysis of phosphate esters of primary alcohols167 was used to advantage by Seegmiller and Horecker,168 who allowed D-glucose to react with polyphosphoric acid and subjected the resulting mixed phosphate to acid hydrolysis to obtain D-glucose 6-phosphate. 

Phosphorylation. Cherbuliez and Rubinowitz used polyphosphoric acid for the preparation of monophosphates of amino alcohols and hydroxy esters. Hall and Khorana used a mixture of 85% phosphoric acid and PjOs for the synthesis of uridine-5 -phosphate. 

Phosphoric and Polyphosphoric Acid Esters, R(OC2H4)xOP(0)(0 M+)2 and [R(OC2H4)xO]2P(0)0 M+ Mainly phosphated POE alcohols and phenols, some sodium alkyl phosphates (not oxyethylenated). The POE materials are available in free acid form or as sodium or amine salts. Products are mixtures of monobasic and dibasic phosphates. 

When the ester interchange step is completed, a phosphorus compound, usually an organic phosphate, phosphite, or polyphosphoric acid, is added to complex the El catalyst and thus deactivate it. Antinomy oxide, or less commonly germanium or titanium oxides, is added at a level of 150 to 450 ppm to serve as a polycondensation (PC) catalyst. The mixture is heated to 280-295 C, and a vacuum of... 

Mixtures of novel nonionic derivatives of phosphate esters of polyoxyethylenated partial glycerides of higher fatty acids are manufactured by reacting ethoxylated fatty mono- and diglycerides with polyphosphoric acid containing 82-84% P4O10, followed by treatment of the reaction products with ethylene oxide or propylene oxide. 

When plastic or other materials that contain APP are exposed to an accidental fire or heat, the flame retardant starts to decompose commonly into polymeric phosphoric acid and ammonia. The polyphosphoric acid reacts with hydroxyl or other groups of a synergist to form an unstable phosphate ester. Dehydration of the phosphate ester then follows. Carbon foam is built up on the surface against the heat source (charring). The carbon barrier acts as an insulation layer, preventing further decomposition of the material. 

The principal phosphation reagents used to manufacture phosphate esters are phosphoric anhydride (P4O10), phosphorus oxychloride [P(0)Cl3], and polyphosphoric acid. It is important to understand the physical and chemical characteristics of each raw material. The structure of the phosphation agent affects its reactivity and selectivity, resulting in variation in the monoester, diester, and triester product distribution. 

By ( clization of N-(l-adamantoyl)-N -methyl-o-phenylenediamine in absolute chloroform and alcohol environment, in the presence of polyphosphoric aeid ester (ppe), l-methyl-2-(adamantyl)benzimidazole (79) is obtained with 35% yield. 6-nitrobenzimidazole-2-earboxylic acid-(l-adamantylamide)-l-oxyde (80) was obtained with 3% yield by treatment of l-(N-2,4-dinitro-phenylgli( lamino)adamantane in pH 8.5 phosphate buffer, at 90 C during 136 hours. 

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