Condensation polyphosphoric acids

Other condensed polyphosphoric acids have the general formula Hn+2Pn03n+1, and they are formally produced by the elimination of water between the (n — 1) acid and a molecule of ff3P04. The general structure can be represented as... 

ESTER CONDENSATION Polyphosphoric acid. Potassium hydride. 

GB started commercial manufacture of white P from bones Concluded phosphate of lime was the important nutrient in bones Condensed polyphosphoric acids prepared P-containing Lecithin first isolated from egg yolk Phosphate rock first mined in Suffolk, England Discovered thiophosphoric esta-s Inosinic acid isolated from beef muscle Existence of trimethylphosphine, PMe, reported First preparation of red phosphorus... 

A simplified procedure is possible by using polyphosphoric acid as the condensing agent. Add 160 g. of polyphosphoric acid to a solution of 11 g. of resorcinol in 13 g. of ethyl acetoacetate. Stir the mixture and heat at 75-80° for 20 minutes, and then pour into ice-water. Collect the pale yellow solid by suction filtration, wash with a little cold water, and dry at 60°. The yield of crude 4-methyl-7-hydroxycoumarin, m.p. 178-181°, is 17 g. Recrystalbsation from dilute ethanol yields the pure, colourless compound, m.p. 185°. 

Evaporated milk is a Hquid product obtained by the partial removal of water only from milk. It has a minimum milk-fat content of 7.5 mol % and a minimum milk-solids content of 25.0 mol %. Evaporated skimmed milk is a Hquid product obtained by the partial removal of water only from skimmed milk. It has a minimum milk-solids content of 20.0 mol %. Sweetened condensed milk is a product obtained by the partial removal of water only from milk with the addition of sugars. It has a minimum milk-fat content of 8.0 mol % and a minimum milk-solids content of 28.0 mol %. Skimmed sweetened condensed milk is a product obtained by the partial removal of water only from skimmed milk with the addition of sugars. It has a minimum milk-solids content of 24.0 mol %. AH may contain food additives (qv) as stabilizers, in maximum amounts, including sodium, potassium, and calcium salts of hydrochloric acid at 2000 mg/kg singly citric acid, carbonic acid, orthophosphoric acid, and polyphosphoric acid at 3000 mg/kg in combination, expressed as anhydrous substances and in the evaporated milk carrageenin may be added at 150 mg/kg. 

Commercial condensed phosphoric acids are mixtures of linear polyphosphoric acids made by the thermal process either direcdy or as a by-product of heat recovery. Wet-process acid may also be concentrated to - 70% P2O5 by evaporation. Liaear phosphoric acids are strongly hygroscopic and undergo viscosity changes and hydrolysis to less complex forms when exposed to moist air. Upon dissolution ia excess water, hydrolytic degradation to phosphoric acid occurs the hydrolysis rate is highly temperature-dependent. At 25°C, the half-life for the formation of phosphoric acid from the condensed forms is several days, whereas at 100°C the half-life is a matter of minutes. 

Pyrophosphoric (diphosphoric) acid, H4P2O2, is the only condensed phosphoric acid definitely obtainable ia crystalline form. It has a theoretical P2O5 content of 79.8%. However, Hquid polyphosphoric acid of such content shows by analysis only 42.5% the remainder is phosphoric acid and... 

Condensed Phosphoric Acid. The largest use of polyphosphoric (superphosphoric) acid is as an intermediate in the production of high quahty Hquid fertilizers. The TVA pioneered the development of electric-furnace superphosphoric acid for this appHcation. However, wet-process superphosphoric acid prepared by evaporation of water from wet-process phosphoric acid has almost completely replaced furnace-grade acid in fertilizer manufacture. 

Triphenylene has been prepared by self-condensation of cyclohexanone using sulfuric acid or polyphosphoric acid followed by dehydrogenation of the product, palladium-charcoal, or selenium by electrolytic oxidation of cycloliexanone from chlorobenzene and sodium or phenyllilhium from 2-cyclolu xyl-l-phenylcyelohexanol or... 

Proceeding from 5 -0-acetylazauridine (80), a mixture of 2 - and 3 -monophosphates (81, 82) was prepared by phosphorylation with polyphosphoric acid, and these were converted into the 2, 3 -cyclic phosphate (83). From the 2, 3 -0-isopropylidene derivative of 3-methyl-6-azauridine the 5 -phosphate was prepared by treatment with cyanoethylphosphate and the corresponding diphosphate from its morpholidate through the action of phosphoric acid. ° Furthermore, a diribonucleoside phosphate (85) with a natural 3 -5 internucleotide linkage was prepared from 6-azauridine, The starting material for the preparation of such derivatives was 5 -0-acetyl-2 -0 -tetrahydro-pyranyluridine-3 -phosphate (84) which was condensed with di-G-acetylazauridine (86) or with 2b3 -0-isopropylidene-6-azauridine (76) with the aid of dicyclohexylcarbodiimide. ... 

This ring system may be prepared from 527 by condensation with ami-drazone or aminoguanidine derivatives to afford 528, which on reaction with polyphosphoric acid gave imidaz[5, -/][ ,2,4]triazin-4(2//)one 529... 

Base-catalyzed condensation between phenylacetic acid and phthalic acid produces enol lactone 78, which is reduced to benzoate 79 with HI and phosphorous. Friedel-Crafts cyclization by polyphosphoric acid followed by reduction produces alcohol 80. This alcohol forms ethers exceedingly easily, probably via the carbonium ion. Treatment with N-methyl-4— piperidinol in the presence 6f acid leads to the antidepressant hepzidine (81). 

Condensation of 613 with a-bromo-a-phenylacetophenone gave 614, whose cyclization was effected by polyphosphoric acid to give 615 (82ZOR1272). 

Further condensation of phosphate groups leads to the polyphosphoric acids, which contain several phosphate units. The acids themselves are not particularly useful, but salts of some of these acids are used extensively. Triphosphoric acid, also known as tripolyphosphoric acid, H5P3O10, can be considered as a product of the reaction... 

Polyphosphoric acid in condensation of dibenzyl ketone and acetic acid, 47, 54... 

A powerful and efficient method for the preparation of poly(ketone)s is the direct polycondensation of dicarboxylic acids with aromatic compounds or of aromatic carboxylic acids using phosphorus pentoxide/methanesulfonic acid (PPMA)16 or polyphosphoric acid (PPA)17 as the condensing agent and solvent. By applying both of these reagents to the synthesis of hexafluoroisopropylidene-unit-containing aromatic poly(ketone)s, various types of poly(ketone)s such as poly(ether ketone) (11), poly(ketone) (12), poly(sulfide ketone) (13), and poly-... 

Acidic ring closure resembles the Du Pont process in that the central benzene ring of the quinacridone structure is synthesized totally. The process bears resemblance to the Liebermann method [2, see also 1.3]. Condensation of succinylosuc-cinic ester with two equivalents of arylamine affords 2,5-diarylamino-3,6-dihy-droterephthalic diester. Subsequent oxidation with suitable agents yields 2,5-di-arylaminoterephthalic diester 57. Hydrolysis and cyclization in polyphosphoric acid or other acidic condensation agents produces crude quinacridone [10]. This product already consists of very small particles. 

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