Phosphorus anhydride

Ethyl-lsonicotinic Nitrile The 11 grams of the amide just obtained are treated with 15 grams of phosphorus anhydride at 160° to 180°C in a vacuum. 6 grams of a liquid residue are obtained. 

Crystalline and amorphous substances that are stable in the air and do not decompose when heated in the temperature interval from 100 to 130 °C are dried in a drying cabinet. The same substances can be dried in the air and in a desiccator over phosphorus anhydride, anhydrous calcium chloride, or concentrated sulphuric acid. 

SCHEME 5.2 Formation of phosphorus anhydride cross-links in phosphorylated poly(vinyl alcohol). 

Dry lead nitrate and quartz sand in a drying cabinet at 120 °C. Assemble an apparatus as shown in Fig. 86a. Put a mixture of 70 g of finely comminuted lead nitrate and 20 g of dry quartz sand into retort 1. Fill columns 2 and 3 with phosphorus anhydride applied onto glass wool. Place thoroughly dried receiver 4 into a beaker with dry ice . Heat the retort with a strong burner flame. Give attention to how the colour of the gas changes in liquefaction. 

AnoAer procedure which was thought to pass through a mixed phosphorus anhydride was the acylation of Grignard reagents with an adduct formed between lithium carboxylates and triphenylphosphine dichloride (Scheme 26). The betaine (70) was the proposed tetrahedral intermediate however, since no evidence is provided, Ae reaction may have also proceeded by way of the acid chloride. Surprisingly, good yields of ketone are preserved even in the presence of excess nucleophile and no tertiary alcohol formation was observed. Triethylamine can be used for prior deprotonation of the carboxylic acid how-... 

Bonds to Oxygen.—Compounds of Lower Oxidation State. Mixed sulphur-phosphorus anhydrides result when sulphonic acids and dialkyl hydrogen phosphites react according to equation (17).448 Further work on the preparation of trimethylsilyl esters of phosphorous acids has been carried out by... 

The insertion of ethylene oxide into a phosphorus anhydride bond has been invoked by several authors. Examples are shown in Fig. 7. The first example of this reaction is shown in the work of... 

Third, the synthesis of phosphorus anhydrides is the final step toward... 

As previously noted (Introduction) a number of metal-containing polyesters have been synthesized employing organometallic dihalides and salts of dicarboxylic acids. Further the synthesis of phosphorus-containing polyesters and polyamides has also been accomplished (for instance 11-15). Previous attempts by our group to synthesize the analogous phosphorus anhydrides failed. 

When the temperature is very high (>100CPC) phosphorus-containing acids are completely dehydrated to form a phosphorus anhydride [82],... 

The basic product of phosphorous oxidation is phosphorus anhydride 1 0,0, which can sublime at -347°C. It forms acids in the presence of moisture. The reaction between phosphorus vapors and oxygen can take place in two different ways ... 

Comments Acts on phosphorus anhydride bonds (such as phosphorus-halide and phosphorus-cyanide) in organophosphorus compoimds (including "nerve gases"). Inhibited by chelating agents requires divalent cations. Related to EC 3.1.8.1 aryldialkylphosphatase. Previously listed as EC 3.8.2.I. 

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