Potassium oxides

Over the years, HteraHy thousands of catalyst formulations have been evaluated and those available today are significantly more active, which has allowed considerable improvement in productivity and plant operation. Today, a typical catalyst contains approximately 93 wt % Fe O, and about 1 wt % potassium oxide, 3 wt % alumina, 3 wt % calcium oxide, and 0.5 wt % siHca, which is actually an unnecessary impurity. 

Steam reforming is the reaction of steam with hydrocarbons to make town gas or hydrogen. The first stage is at 700 to 830°C (1,292 to 1,532°F) and 15-40 atm (221 to 588 psih A representative catalyst composition contains 13 percent Ni supported on Ot-alumina with 0.3 percent potassium oxide to minimize carbon formation. The catalyst is poisoned by sulfur. A subsequent shift reaction converts CO to CO9 and more H2, at 190 to 260°C (374 to 500°F) with copper metal on a support of zinc oxide which protects the catalyst from poisoning by traces of sulfur. 

A characteristic feature of aromatic fluorodenitration is modest yield due to side reactions promoted by potassium nitrite and/or its decomposition product, potassium oxide, with the aryl fluoride or starting material... 

The use of phthaloyl dichlonde as a scavenger for potassium nitrite and/or potassium oxide [108, 109, III] significantly increases yields of aryl fluorides, m fluoronitrobenzene is obtained in 70% yield with sulfolane as a solvent at 200 °C after 72 h Addition of tetraphenylphosphonium bromide as a phase-transfer catalyst to the phthaloyl dichlonde scavenger system further increases the yield of m-fluoronitrobenzene to 89% under less forcing conditions 150-180 C, 5 h) [if 2] This optimized technique can be applied to give m-fluorobenzonitnle from in-m-trobenzonitnle in 86% yield [/i2]... 

Kalium-oxyd, n. potassium oxide, -oxydhydrat, n. potassium hydroxide, -permangaoat, n. potassium permanganate, -platinchlorid, n. potassium chloroplatinate, potassium chlo-roplatinate(IV). -platmchloriir, n. potassium chloroplatinite, potassium chloroplatinate (II). -platmcyaniir, n. potassium cyano-platinite, potassium cyanoplatinate(II). 

The goal of Haber s research was to find a catalyst to synthesize ammonia at a reasonable rate without going to very high temperatures. These days two different catalysts are used. One consists of a mixture of iron, potassium oxide. K20, and aluminum oxide. Al203. The other, which uses finely divided ruthenium, Ru. metal on a graphite surface, is less susceptible to poisoning by impurities. Reaction takes place at 450°C and a pressure of 200 to 600 atm. The ammonia... 

A yield of approximately 98% can be obtained at 200°C and 1000 atmospheres of pressure. The process makes use of a catalyst which is usually finely divided, mixed iron oxides containing small amounts of potassium oxide, K20, and aluminum oxide, Al203. 

Potassium Oxide (Potassium Monoxide). K20, mw 94.20, white, loose, deliq powd, mp 350° (decompn), d 2.32g/cc at 0°, Reacts with w very readily to form KOH with evotn of 75 kcal/mole. V sol in w, si sol in ethanol and eth. Prepn is by mildly heating carefully purified K in the presence of pure dry air. Excess K is distd off at 350° under high vacuum. The K20 is 99.5% pure. Also produced when K compds are burned in pyrots... 

Eerrocene (1) was the first sandwich complex to be discovered, thereby opening a wide and competitive field of organometallic chemistry. The formation of ferrocene was found at almost the same time in two independent studies on July 11, 1951, Miller, Tebboth, and Tremaine reported that on the passage of N2 and cyclopenta-diene over a freshly prepared mixture of reduced Ee (90%), alumina (8%), potassium oxide (1%), and molybdenum oxide (1%) at 300°C, yellow crystals identified as Cp2Ee (Eig. 1) were obtained [1]. Due to the low yields obtained (3 g starting from 650 g ferric nitrate), doubts remain as to whether Ee(0) was the... 

C03-0068. Write chemical formulas for these compounds (a) potassium chlorate (b) ammonium hydrogen carbonate (c) iron(II) phosphate (d) copper(II) nitrate hexahydrate (e) aluminum chloride (Q cadmium(II) chloride and (g) potassium oxide. 

Experiments and calculations both indicate that electron transfer from potassium to water is spontaneous and rapid, whereas electron transfer from silver to water does not occur. In redox terms, potassium oxidizes easily, but silver resists oxidation. Because oxidation involves the loss of electrons, these differences in reactivity of silver and potassium can be traced to how easily each metal loses electrons to become an aqueous cation. One obvious factor is their first ionization energies, which show that it takes much more energy to remove an electron from silver than from potassium 731 kJ/mol for Ag and 419 kJ/mol for K. The other alkali metals with low first ionization energies, Na, Rb, Cs, and Fr, all react violently with water. 

Modification of Y-AI2O3 by K cation was shown to form a potassium oxides layer. This layer blocks the alumina surface and decreases drastically (> 99%) the catalytic activity with respect to pure Y-AI2O3... 

Several pilot plants have been built to test periodic flow direction reversal. Pilot-scale reactors with bed diameters from 1.6 to 2.8 m were operated with flow reversal for several years. The units, described by Bunimovich et al. (1984,1990) and Matros and Bunimovich (1996), handled 600 to 3000 m3/h and operated with cycle periods of 15 to 20 min. Table VIII shows the performance of these plants for different feeds and potassium oxide promoted vanadia catalysts. The SVD catalyst was granular the IK-1-4 was in the form of 5 (i.d.) x 10-mm cylinders, while the SYS catalyst was... 

Potash (composed of potassium oxide), also a flux, was mainly used as a glass modifier. It was generally introduced into the glass melt in the form of either pearl ash, composed of potassium carbonate, vegetable ash, one of the main constituents of which is potassium carbonate, or saltpeter, a mineral composed of potassium nitrate. 

Soda (composed of sodium oxide) and potash (composed of potassium oxide) are relatively easy to obtain or to make, work, and handle. Although they do not occur naturally, they could be quite easily prepared in the past by burning some plants (see Textbox 28). Both these oxides were used as fluxes for making early types of glass articles, particularly small vessels and decorative objects. 

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