Magnesium oxide catalysis

A General Description of the Hydrazine Perchlorate Deflagration Process. Let us first describe the deflagration process for hydrazine perchlorate from the above results. It is a process characterized by the formation of a molten zone which is quite turbulent and foamy it is a very erratic process, particularly for the pure material, and it is subject to very potent catalysis by copper chromite and potassium dichromate and to moderate catalysis by magnesium oxide. The process is comparatively reproducible in the presence of small amounts of fuel, and the rate obtained apparently does not depend on the nature of the fuel but only on the ambient pressure. It can be expressed by r — 0.22P where f is in cm./sec. and P in atmospheres. This corresponds to a rate, at 1 atm., some 15 times greater than that calculated by extrapolation for ammonium perchlorate (16). However the process is unstable at pressures above about 7 atm. and steady deflagration cannot be attained above this pressure. 

We attribute the effects of copper chromite, potassium dichromate, and magnesium oxide to catalysis of condensed phase reactions in view of the catalysis of the pyrolysis reaction by species of this type (11). 

OTHER COMMENTS magnesium oxide may be used in the manufacture of refractories, particularly for linings of steel furnaces use as a reflector in optical instruments, in the removal of sulfur dioxide from stack gases, and in adsorption and catalysis other uses include pharmaceuticals, cosmetics, electrical insulation, and paper manufacture. 

Aramendia. MA Borau. V Jimenez, C Marinas. JM Porras. A Urbano, FJ. Magnesium oxides as ba.sic catalysts for organic processes. Study of the dehydrogenation-dehydration of 2-propanol. Journal of Catalysis. 1996 I6I. 829-838. 

Zhang, G Hatton, H Tanabe, K. Aldol condensation of acetone acetone d6 over magnesium oxide and lanthanum oxide. Applied Catalysis, 1988 40. 183-190,... 

Zhang. G Hattori, II Tanabe, K. Aldol adition of acetone, catalyzed by solid base catalysts magnesium oxide, calcium oxide, strontium oxide, lanthanum (iii) oxide and zirconium oxide. Applied Catalysis, 1988 36. 189-197. 

In the context of heterogeneous asymmetric catalysis, Choudary et al. " reported a recyclable heterogeneous nanocrystalline magnesium oxide catalyst for the AH and AM reactions to afford chiral nitro alcohols and Michael adducts in good to excellent yields and enantioselectivities (ee s) (Scheme 5.1). 

The mechanisms discussed in this chapter will provide some insights into the reaction pathways. More detailed investigations are warranted in order to determine the role of the surface, crystal shape, size, and comer/edge positions of nanocrystalline magnesium oxide. Most importantly, the effective role of the acidic and basic sites of nanocrystalline magnesium oxide in catalysis remains to be determined. The work presented in this chapter hopefully opens a new dimension in the area of heterogeneous asymmetric catalysis and for the synthesis of chiral products. 

Keh CCK, Namboodiri VV, Varma RS, Li C-J (2002) Direct formation of tetrahydropy-ranols via catalysis in ionic liquid. Tetrahedron Lett 43 4993 996 Kumar D, Reddy VB, Mishra BG, Rana RK, Nadagouda MN, Varma RS (2007) Nano sized magnesium oxide as catalyst for the rapid and green synthesis of substituted 2-amino-2-cromenes. Tetrahedron 63 3093... 

The first catalyst used in the oxo-reaction was the solid Fischer-Tropsch catalyst consisting of 66% of silica, 30% of cobalt, 2% of thorium oxide and 2% of magnesium oxide. It took quite some time until the homogeneous nature of the catalysis in the oxo reaction was discovered [1, 2, 6] and proved [100]. After this discovery a large number of metals and metal salts were investigated for their use as oxo catalysts. 

The influence of catalysis on mechanical strength and durability has been systematically studied in the catalytic reaction of isopropanol dehydrogenation using a porous magnesium oxide catalyst [6,48,112,116]. The compressive strength of the catalyst pills was lowered by 1.5-2 times when the reaction was in progress for 20-30 s, even prior to reaching the steady state. In these experiments, the measurements were conducted after the samples had been pulled out of the reactor and dried. 

Resoles are usually those phenolics made under alkaline conditions with an excess of aldehyde. The name denotes a phenol alcohol, which is the dominant species in most resoles. The most common catalyst is sodium hydroxide, though lithium, potassium, magnesium, calcium, strontium, and barium hydroxides or oxides are also frequently used. Amine catalysis is also common. Occasionally, a Lewis acid salt, such as zinc acetate or tin chloride will be used to achieve some special property. Due to inclusion of excess aldehyde, resoles are capable of curing without addition of methylene donors. Although cure accelerators are available, it is common to cure resoles by application of heat alone. 

A second nonselective synthesis involved chain extension of the tosylate of ( )-citronellol (82) with 2-methylpentyl magnesium bromide and lithium tetrachlorocuprate catalysis to give the carbon skeleton 83 (Scheme 12A) [92]. Allylic oxidation with Se02 and ferf-butylhydroperoxide, hydrogenation of the... 

The selective intercalation of guests into solid hosts offers the potential for application in catalysis and separation science. An excellent case in point is zeolites, which exhibit shape and size selective inclusion properties and are used for an enormous variety of processes [44,45]. Additionally, a munber of layered materials have been reported to possess selective intercalation properties, including layered metal phosphonates [46,47], montmorUlonite [48], magnesium aluminum oxide [49], and layered double hydroxides [50-59]. 

The experimental simplicity of Method 3 has attracted the specialists in modern trends in catalysis. Thus, in Method 3 different authors used RbF (04SC4431), MgO (09EJM3805), KF/AI2O3, mixed magnesium-aluminum carbonate, or mixed magnesium-lanthanum oxide (08TL2730) in methanol. Recently, 2-aminopyran syntheses with acetylacetone 35 and ethyl acetoacetate 36 were carried out in an ionic liquid [(bmim)(BF4), 1-butyl-3-methylimidazolium borofluoride] with 1,1,3,3-tetramethylguanidine as... 

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