Potassium phosphoric acid

The crude acetonitrile contains as impurity chiefly acetic acid, arising from the action of phosphoric acid on the acetamide. Therefore add to the nitrile about half its volume of water, and then add powdered dry potassium carbonate until the well-shaken mixture is saturated. The potassium carbonate neutralises any acetic acid present, and at the same time salts out the otherwise water-soluble nitrile as a separate upper layer. Allow to stand for 20 minutes with further occasional shaking. Now decant the mixed liquids into a separating-funnel, run off the lower carbonate layer as completely as possible, and then pour off the acetonitrile into a 25 ml, distilling-flask into which about 3-4 g. of phosphorus pentoxide have been placed immediately before. Fit a thermometer and water-condenser to the flask and distil the acetonitrile slowly, collecting the fraction of b.p. 79-82°. Yield 9 5 g. (12 ml.). 

The functions of the potassium carbonate are (a) to neutralise the acetic acid arising from the action of the phosphoric acid upon the acetamide, and (6) to salt out the otherwise soluble methyl cyanide as an upper layer. 

Sulfuric acid (H2SO4) and phosphoric acid (H3PO4) are the acids most frequently used m alcohol dehydrations Potassium hydrogen sulfate (KHSO4) is also often used... 

Other Compounds. Primary and secondary amines add 1,4- to isoprene (75). For example, dimetbylamine in ben2ene reacts with isoprene in the presence of sodium or potassium to form dimetby1(3-metby1-2-buteny1)amine. Similar results are obtained with diethylamine, pyrroHdine, and piperidine. Under the same conditions, aniline and /V-metbylaniline do not react. Isoprene reacts with phenol in the presence of aluminum phenoxide (76) or concentrated phosphoric acid (77) to give complex products. 

Suitable catalysts include the hydroxides of sodium (119), potassium (76,120), calcium (121—125), and barium (126—130). Many of these catalysts are susceptible to alkali dissolution by both acetone and DAA and yield a cmde product that contains acetone, DAA, and traces of catalyst. To stabilize DAA the solution is first neutralized with phosphoric acid (131) or dibasic acid (132). Recycled acetone can then be stripped overhead under vacuum conditions, and DAA further purified by vacuum topping and tailing. Commercial catalysts generally have a life of about one year and can be reactivated by washing with hot water and acetone (133). It is reported (134) that the addition of 0.2—2 wt % methanol, ethanol, or 2-propanol to a calcium hydroxide catalyst helps prevent catalyst aging. Research has reported the use of more mechanically stable anion-exchange resins as catalysts (135—137). The addition of trace methanol to the acetone feed is beneficial for the reaction over anion-exchange resins (138). 

However, the peroxomonophosphate ion decomposes relatively rapidly ia aqueous solution. A mixture of peroxodiphosphoric and peroxomonophoshoric acids can be produced by treatiag a cold phosphoric acid solution with elemental fluorine (qv) (49). Peroxodiphosphoric acid is not produced commercially. Ammonium, lithium, sodium, potassium, mbidium, cesium, barium, 2iac, lead, and silver salts have all been reported. The crystal stmctures of the ammonium, lithium, sodium, and potassium compounds, which crysta11i2e with varyiag numbers of water molecules, have been determined (50). 

Orthophosphate salts are generally prepared by the partial or total neutralization of orthophosphoric acid. Phase equiUbrium diagrams are particularly usehil in identifying conditions for the preparation of particular phosphate salts. The solution properties of orthophosphate salts of monovalent cations are distincdy different from those of the polyvalent cations, the latter exhibiting incongment solubiUty in most cases. The commercial phosphates include alkah metal, alkaline-earth, heavy metal, mixed metal, and ammonium salts of phosphoric acid. Sodium phosphates are the most important, followed by calcium, ammonium, and potassium salts. 

Potassium Phosphates. The K2O—P20 —H2O system parallels the sodium system in many respects. In addition to the three simple phosphate salts obtained by successive replacement of the protons of phosphoric acid by potassium ions, the system contains a number of crystalline hydrates and double salts (Table 7). Monopotassium phosphate (MKP), known only as the anhydrous salt, is the least soluble of the potassium orthophosphates. Monopotassium phosphate has been studied extensively owing to its piezoelectric and ferroelectric properties (see Ferroelectrics). At ordinary temperatures, KH2PO4 is so far above its Curie point as to give piezoelectric effects in which the emf is proportional to the distorting force. There is virtually no hysteresis. 

Anhydrous monocalcium phosphate, Ca(H2PObe made in a pan mixer from concentrated phosphoric acid and lime. The high heat of reaction furnishes essentially all the necessary thermal input and subsequent drying is minimized. A small amount of aluminum phosphate or a mixture of sodium and potassium phosphates is added in the form of proprietary stabilizers for coating the particles. Heat treatment converts the coating to a protective polyphosphate (19). 

U.S. consumption of industrial-grade phosphoric acid and phosphates in 1993 according to product categories (34) was phosphoric acid, at 29% sodium phosphate, 52% calcium phosphate, 7% potassium phosphate, 3% ammonium phosphate, 5% and others, 4%. Consumption according to market is given in Table 12. 

About 264,000 metric tons of elemental capacity is available in North America, plus another 79,000 t (P equivalent) of purified wet phosphoric acid (14). About 85% of the elemental P is burned to P2 5 hydrated to phosphoric acid. Part of the acid (ca 21%) is used direcdy, but the biggest part is converted to phosphate compounds. Sodium phosphates account for 47% calcium, potassium, and ammonium phosphates account for 17%. Pinal apphcations include home laundry and automatic dishwasher detergents, industrial and institutional cleaners, food and beverages, metal cleaning and treatment, potable water and wastewater treatment, antifree2e, and electronics. The purified wet acid serves the same markets. 

Devising an economical method of producing agricultural-grade potassium phosphates from potassium chloride and wet-process phosphoric acid has been the subject of intense agricultural—chemical research (37—39). Limited quantities have been produced industrially. The impact on the overall quantities of phosphoms and potassium compounds consumed by the fertilizer industry is small. Because potassium phosphates are an excellent source of two essential fertilizer elements, this research is expected to continue. 

A method suitable for analysis of sulfur dioxide in ambient air and sensitive to 0.003—5 ppm involves aspirating a measured air sample through a solution of potassium or sodium tetrachloromercurate, with the resultant formation of a dichlorosulfitomercurate. Ethylenediaminetetraacetic acid (EDTA) disodium salt is added to this solution to complex heavy metals which can interfere by oxidation of the sulfur dioxide. The sample is also treated with 0.6 wt % sulfamic acid to destroy any nitrite anions. Then the sample is treated with formaldehyde and specially purified acid-bleached rosaniline containing phosphoric acid to control pH. This reacts with the dichlorosulfitomercurate to form an intensely colored rosaniline—methanesulfonic acid. The pH of the solution is adjusted to 1.6 0.1 with phosphoric acid, and the absorbance is read spectrophotometricaHy at 548 nm (273). 

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

Chemical Processing. Activated carbon consumption in a variety of chemical processing appHcations is about 8% of the total (74). The activated carbon removes impurities to achieve high quaHty. For example, organic contaminants are removed from solution in the production of alum, soda ash, and potassium hydroxide (82). Other apphcations include the manufacture of dyestuffs, glycols, amines, organic acids, urea, hydrochloric acid, and phosphoric acid (83). 

Ethyl Acetate. Catalysts proposed for the vapor-phase production of ethyl acetate include siUca gel, zirconium dioxide, activated charcoal, and potassium hydrogen sulfate. More recendy, phosphoric-acid-treated coal (65) and calcium phosphate (66) catalysts have been described. 

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