Catalyst ammonium phosphate

In 1994, DuPont [18] patented the ammonolysis process, in which PA6 and PA66 react with ammonia in the presence of a catalyst (ammonium phosphate) and as a result the corresponding monomers can be obtained. A high purity of the waste polyamides (98%) is required. The process conditions are 300-350°C and pressure of 68.9 MPa [18,40,41]. 

Ammonolysis is the preferred route currently in use at the DuPont Company for the depolymerization of nylon-6,6 carpet waste. McKinney13 has described the reaction of nylon-6,6 and nylon-6 mixtures with ammonia at temperatures in the range of 300-350°C at a pressure of about 68 atm in the presence of an ammonium phosphate catalyst to form a mixture of nylon-6,6 and nylon-6 monomers (HMD A, A A, and s-caprolactam) and adiponitrile, 5-cyanovaleramide, 6-aminocapronitrile, and 6-aminocaproamide. 

Methylated 1,4-dihydropyrazines (1,2,4-tri-, 1,2,4,5-tetra-, and 1,2,4,6-tetramethyl) as well as imidazolines have been isolated from the reaction of sucrose with methylamine at high temperatures (120°-260°), for prolonged reaction periods (18 hours) and in the presence of ammonium phosphate as catalyst. 1,4-Dihydropyrazines are also isolated from the reaction of sucrose and ethanolamine sucrose-ammonia interaction yields a wide range of pyrazines and imidazoles.369-372... 

By far the largest use of sulfuric acid is in the production of phosphate fertilizers, e.g. ammonium phosphate. Other large uses are as solvent for copper and nickel minerals and as catalyst for petroleum refining and polymer manufacture. 

In a very early study Patat (1945) investigated the hydrolysis of aniline to phenol in a water-based acidic solution in near-critical and supercritical water (Tc = 374.2°C, Pc = 220.5 bar). Phosphoric acid and its salts are used as the catalyst for this reaction. The reaction proceeds extremely slowly under normal conditions and reaches equilibrium at low conversion levels. For these reasons, Patat chooses to study the reaction in supercritical water to temperatures of 450°C and to pressures of 700 bar in a flow reactor. He finds that the reaction follows known, regular kinetics in the entire temperature and pressure space studied and the activation energy of the hydrolysis (approximately 40 kcal/mol) is the same in the supercritical as well as in the subcritical water. He suggests that the reaction is catalyzed by hydrogen ions formed from dissolution of phosphoric acid in supercritical steam. Very small amounts of phosphoric acid and the salts of the phosphoric acid are dissolved in the supercritical steam and are split into ions. Patat lists several dissolution constants for primary ammonium phosphates in supercritical steam. In this instance, the reaction performance is improved when the reaction is operated homogeneously in the mixture critical region and, thus, in intimate contact between the reactants and the catalyst. 

The catalyst or add source can consist of ammonium phosphate or polyphosphate salts, phosphoric add-derived amides or alkyl or halo-alkyl phosphates. Charring agents are based on molecular structures that can form cross-linked networks such as pentaerythritol, sorbitol, melamine, and phenol-formaldehyde resins. Other polymeric systems capable of intumescence are some polyamides and polyurethanes. Blowing agents help form a porous structure in the char and can fadlitate its formation. Common blowing agents are based on urea and urea-formaldehyde resins, melamines, and polyamides that can liberate moisture. 

Aminopyradine, MA adduct formation, 238 Ammonia, MA reaction, 81, 85, 511 Ammonium bromide, isomerization catalyst, 13 Ammonium chloride, catalyst, 47 Ammonium persulfate, isomerization catalyst, 13 Ammonium phosphate, MA distillation additive, 22 Ammonium sulfate, MA distillation additive, 22 Anethole see p-Propenyl-anisole Anhydrides, cyclic, hydrolysis, 73, 74 Aniline... 

In an alternative industrial process, resorcinol [108-46-3] is autoclaved with ammonia for 2—6 h at 200—230°C under a pressurized nitrogen atmosphere, 2.2—3.5 MPa (22—35 atm). Diammonium phosphate, ammonium molybdate, ammonium sulfite, or arsenic pentoxide maybe used as a catalyst to give yields of 60—94% with 85—90% selectivity for 3-aminophenol (67,68). A vapor-phase system operating at 320°C using a siUcon dioxide catalyst impregnated with gallium sesquioxide gives a 26—31% conversion of resorcinol with a 96—99% selectivity for 3-aminophenol (69). 

Dutch State Mines (Stamicarbon). Vapor-phase, catalytic hydrogenation of phenol to cyclohexanone over palladium on alumina, Hcensed by Stamicarbon, the engineering subsidiary of DSM, gives a 95% yield at high conversion plus an additional 3% by dehydrogenation of coproduct cyclohexanol over a copper catalyst. Cyclohexane oxidation, an alternative route to cyclohexanone, is used in the United States and in Asia by DSM. A cyclohexane vapor-cloud explosion occurred in 1975 at a co-owned DSM plant in Flixborough, UK (12) the plant was rebuilt but later closed. In addition to the conventional Raschig process for hydroxylamine, DSM has developed a hydroxylamine phosphate—oxime (HPO) process for cyclohexanone oxime no by-product ammonium sulfate is produced. Catalytic ammonia oxidation is followed by absorption of NO in a buffered aqueous phosphoric acid... 

In order to obtain a sufficient rate of cure at moulding temperatures it is usual to add about 0.2-2.0% of a hardener (accelerator). This functions by decomposing at moulding temperatures to give an acidic body that will accelerate the cure rate. A very large number of such latent acid catalysts have been described in the literature, of which some of the more prominent are ammonium sulphamate, ammonium phenoxyacetate, ethylene sulphite and trimethyl phosphate. 

Regeneration was based on removing ammonium dihydrogen phosphate, formed in hydrogenolysis of benzocaine, from the catalyst. The catalyst was... 

Eight samples from each set (A and D) were split into two groups, one incubated in 0.15 M phosphate buffered solution (PBS) and the other in PBS containing 0.1% of the phase transfer catalyst, tricapryl methyl ammonium chloride (Aldrich Aliquot 336) (PBS, catalyzed), both at pH 7.4. The samples were suspended in centrifuge tubes with 10 mL of incubation solution by nylon string and the tubes were placed in a shaker bath at a constant temperature of 37°C. Periodically, the samples were taken out of the tubes, placed on lint free paper towels, allowed to dry for exactly one hour, weighed and placed in fresh incubation media. The total time of the study was 48 weeks (330 days). 

Diethyl phosphate esters of the sterically congested phenols of calixarenes have been prepared in acceptable yields (>55%) and used in the preparation of meta-cyclophanes [8]. The corresponding reaction using diethyl phosphite, with triethylamine in place of the quaternary ammonium catalyst, results in only partial phosphorylation of the hydroxyl groups. 

C EN 42, 50-3 (Sept 28, 1964) [Description of cast composite proplnts manufd at Aerojet -General Plant, near Homestead, Florida, for use in large rocket motors, such as 120 156l, diam. Ammonium perchlorate, (previously ground to particles ranging from 1 to 2 microns and blended with ca 0.2% of tricalcium phosphate to improve their flow props), is used as an oxidizer. Aluminum powder is used as a fuel and liquid polybutadiene-acrylonitrite as the fuel-binder. To these ingredients are added a catalyst, such as iron oxide (to... 

A new catalyst salt (20) that consists of an achiral ammonium ion and a chiral phosphate anion and which catalyses highly enantioselective transfer hydrogenations of ,/J-unsaturated aldehydes to the corresponding saturated derivatives has been developed. The underlying principle, namely asymmetric counteranion-directed catalysis, is claimed to be a new strategy for highly enantioselective synthesis.357... 

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