Phosphoric acid condensation reactions

Phosphoramidous fluorides, 13 383-389 Phosphoranes, 16 47 cage compounds, 30 246 as propellanes, 33 268 Phosphorescence, 19 68 Phosphoric acid ester amides, reaction with hexafluoroacetone, 30 237 Phosphoric acids, condensed, properties of, 5 220... 

In the three-step process acetone first undergoes a Uquid-phase alkah-cataly2ed condensation to form diacetone alcohol. Many alkaU metal oxides, metal hydroxides (eg, sodium, barium, potassium, magnesium, and lanthanium), and anion-exchange resins are described in the Uterature as suitable catalysts. The selectivity to diacetone alcohol is typicaUy 90—95 wt % (64). In the second step diacetone alcohol is dehydrated to mesityl oxide over an acid catalyst such as phosphoric or sulfuric acid. The reaction takes place at 95—130°C and selectivity to mesityl oxide is 80—85 wt % (64). A one-step conversion of acetone to mesityl oxide is also possible. 

The dimer of phosphonic acid, diphosphonic acid [36465-90-4] (pyrophosphoms acid), H4P2O3, is formed by the reaction of phosphoms trichloride and phosphonic acid in the ratio of 1 5. It is also formed by the thermal decomposition of phosphonic acid. Unlike the chemistry of phosphoric acid, thermal dehydration does not lead to polymers beyond the dimer extended dehydration leads to a disproportionation to condensed forms of phosphoric acid, such as [2466-09-3] and phosphine. 

The second major route to diarylamiaes is the condensation of an aromatic amine with a phenol. Aniline [62-53-3] phenol [108-95-2] and 3.5% phosphoric acid at 325°C gives a 50% yield of DPA (23). Apparently, this reaction iavolves the addition of aniline to the keto form of the phenol. Thus, naphthols and hydroquiaone are more reactive and give higher yields of product. This is the preferred route to A/-phenyi-2-naphthyiamiQe, 4-hydroxydiphenyiamiQe, and diphenyl- -phenylenediamine (24). 

Ferrocene (46.4 g., 0.250 mole) (Note 1) is added to a well-stirred solution of 43.2 g. (0.422 mole) of bis(dimethylamino)-methane (Note 2) and 43.2 g. of phosphoric acid in 400 ml. of acetic acid in a 2-1. three-necked round-bottomed flask equipped with a condenser, a nitrogen inlet, and a mechanical stirrer (Note 3). The resulting suspension is heated on a steam bath under a slow stream of nitrogen (Note 4) for 5 hours (Note 5). The reaction mixture, a dark-amber solution, is allowed to cool to room temperature and is diluted with 550 ml. of water. The unreacted ferrocene is removed by extracting the solution with three 325-ml. jiortions of ether. The aqueous solution is then looled in ice water and made alkaline by the addition of 245 g. 

Condensed phosphates are indirectly manufactured derivatives of phosphorous acids, having less water than orthophosphoric acid (two molecules of phosphoric can be written P205 3H20, which indicates the source of the condensation reaction). Condensed phosphates are typically available in either crystalline or glassy forms. 

Resole resins are generally crosslinked under neutral conditions between 130 and 200° C or in the presence of an acid catalyst such as hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, and phenolsulfonic acid under ambient conditions.3 The mechanisms for crosslinking under acidic conditions are similar to acid-catalyzed novolac formation. Quinone methides are the key reaction intermediates. Further condensation reactions in resole resin syntheses under basic conditions at elevated temperatures also lead to crosslinking. 

Ny lon-6 (108 g) carpet backed with calcium-carbonate-filled latex and polypropylene was charged to a 1000-mL three-neck round-bottom flask (equipped with a condenser) with 6 mL of 85% phosphoric acid. Superheated steam was injected continuously during a 45-min period. The vapor temperature of the reaction medium was 250-300°C. The volume of distillate collected was 1065 mL. The distillate contained 1.9% e-caprolactam (as determined by GC), which corresponded to a crude yield of 37.5%. The distillate was fractionated in a distillation column and the nonaqueous phase removed. The remaining aqueous phase was treated with 2% potassium permanganate at 40-50°C for 2 h. Evaporation of... 

The reaction of condensed phosphoric acid with castor oil gave a poly-phosphoric acid ester, which after neutralization with ammonia shows a high wetting power [32]. Glycerol trioleate was reacted with octametaphosphoric acid at 40°C in the presence of acetic acid anhydride. The reaction product was neutralized with triethanolamine [32,33]. 

When phosphoric acid is heated, it undergoes a condensation reaction, a reaction in which two molecules combine together with the elimination of a small molecule, normally that of water ... 

Classical examples of this type of reaction are the various dimethylaminobenz-aldehyde reagents (q.v.) and vanillin-acid reagents, of which one, the vanillin-phosphoric acid reagent, is already included in Volume 1 a. The aldol condensation of estrogens is an example for the reaction mechanism (cf. Chapter 2, Table 6). According to Maiowan indole derivatives react in a similar manner [1]. Longo has postulated that catechins yield intensely colored triphenylmethane dyes [2]. 

Two molecules of phosphoric acid can undergo a condensation reaction, eliminating a water molecule and forming a P—O—phosphate linkage ... 

C13-0024. Nucleotides can contain more than one phosphate group. One example is energy-storing adenosine triphosphate (ATP), which is discussed in Chapter 14. An ATP molecule is formed in two sequential condensation reactions between phosphoric acid and the phosphate group of AMP ... 

C13-0108. The first step of glucose metabolism is an enzyme-catalyzed condensation reaction between phosphoric acid and the CH2 OH hydroxyl on glucose. Draw the structure of this glucose phosphate. 

Phosphoric acid can undergo phosphate condensation, a reaction that is similar to the condensation reactions of other species that contain O—H bonds (see Chapter 13) ... 

The condensation reactions are preferentially carried out in pyridine. As reactive species for phosphorylation of the nucleoside R OH (synthesis of a phosphortriester), the phosphoric acid azolide has been assumed. The mixed phosphoric sulfonic anhydride and a pyrophosphate tetraester have been suggested as intermediates leading to the phosphoric acid azolide. 

Phosphorus acid (260 mg, 3.17 mol) was placed into a 250-ml, threenecked, round-bottomed flask suspended in an oil bath. The flask was equipped with a three-way adapter, carrying a pressure-equalizing addition funnel, a reflux condenser with a drying tube, a mechanical stirrer, and a thermometer. Acetonitrile (33 g, 0.80 mol) was introduced to the reaction flask dropwise over a 2-h period while the phosphorous acid was agitated and maintained at a temperature of 138 to 142°C. After completion of the addition, the reaction mixture was maintained at that temperature for an additional 12 h. Methanol was then added to precipitate the pure l-aminoethane-l,l-diphos-phonic acid (13.9 g, 85%), which exhibited spectral and analytical data in accord with the proposed structure. 

The imine from benzaldehyde and benzyl amine (65 g, 0.33 mol) was added to phosphorous acid (27.3 g, 0.33 mol), and the mixture was stirred with heating. As the temperature reached 95 to 100°C, the entire mixture became a homogeneous liquid, which reacted vigorously as the temperature reached 115 to 120°C. After the reaction mixture became very viscous, it was allowed to cool, whereupon it condensed to a glass. The material was dissolved in aqueous sodium carbonate, which upon acidification precipitated pure N-benzyl a-aminobenzylphosphonic acid (90 g, 98%) of mp 233 to 234°C. The material exhibited analyses in accord with the proposed structure. 

The condensation reaction with aniline may also be accomplished in two separate steps. It is possible to separate succinylosuccinic ester, followed by condensation in boiling ethanol in the presence of an acid (acetic acid, hydrochloric acid, phosphoric acid). 

The use of the triphenylphosphine-di(2-pyridyl) disulphide reagent for effecting condensation reactions has been reviewed.84 Combination of triphenylphosphine with bis(O-thiocarbonyl) disulphide gives a superior reagent compared to that mentioned above for the preparation of mixed diesters of phosphoric acid from monophosphate esters.86... 

Similar to that observed for pure phosphoric acid, the transport properties of PBI and phosphoric acid are also dependent on the water activity, i.e., on the degree of condensation (polyphosphate formation) and hydrolysis. There is even indication that these reactions do not necessarily lead to thermodynamic equilibrium, and hydrated orthophosphoric acid may... 

This reaction is a condensation reaction and is catalysed by concentrated sulfuric acid or concentrated phosphoric acid. 

A mixture of the propanoic acid and the propan-l-ol is heated in the presence of concentrated sulfuric acid (or concentrated phosphoric acid) as a catalyst to form the ester, propyl propanoate. This is a condensation reaction. 

The shikimate pathway begins with a coupling of phosphoenolpyruvate (PEP) and D-erythrose 4-phosphate to give the seven-carbon 3-deoxy-D-arabino-heptulo-sonic acid 7-phosphate (DAHP) through an aldol-type condensation. Elimination of phosphoric acid from DAHP, followed by an intramolecular aldol reaction, generates the first carbocyclic intermediate, 3-dehydroquinic acid. Shikimic acid (394) is... 

Polyquinolines (PQ) are obtained by the Friedlander reaction of a bis-o-aminoaromatic aldehyde (or ketone) with an aromatic hisketomethylene reactant [Concilio et al., 2001 Stille, 1981]. The quinoline ring is formed hy a combination of an aldol condensation and imine formation (Eq. 2-221). Polymerization is carried out at 135°C in m-cresol with poly (phosphoric acid) as the catalyst. The reaction also proceeds under base catalysis, but there... 

Erom natural sources the (R)-enantiomer of ( )-a-ionone is detected with high enantiomeric purity (much more than 99%) hence, the authenticity of ( )-a-ionone is mostly proved via enantio-GC applications [27,65-67]. In the majority of cases synthetic ionones are produced via pseudoionone, prepared by base-catalysed condensation of citral with acetone. After acidic catalysis (using 85% phosphoric acid or concentrated sulphuric acid), this reaction yields racemic ( )-a-ionone and ( )-/l-ionone [68]. 

---