Alumina-supported synthesis

Kidwai, M., Bhushan, K.R., Sapra, P., Saxena, R.K.and Gupta, R., Alumina-supported synthesis ofantibacterial quinolines using microwaves, Bioorg. Med. Chem., 2000, 8, 69-72. 

In an alumina-supported synthesis of antibacterial quinolines using microwaves wherein the reaction times were brought down from hours to seconds with improved yield as compared to the conventional heating (Scheme 78)7 ... 

Alumina-Supported Synthesis of Antibacterial Quinolines Using Microwaves. 174... 

Kidwai M, Bhushan KR, Sapra P, Saxena RK, Gupta R (2000) Alumina-supported synthesis of antibacterial quinolines using microwaves. Bioorg Med Chem 8 69-72... 

Singh V, Kumari PL, Tiwariy A et al (2007) Alumina supported synthesis of cassia marginata gum-g-poly(acrylonitrile) under mioowave irradiation. Polym Adv Technol 18 379-385... 

Table 7. KF-alumina supported synthesis of 2-aminothiophenes 23 under a) microwave irradiation and b) conventional heating...

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Thiazolines (2,3-dihydrothiazoles) were also prepared under microwave irradiation. Hamelin and coworkers have described the alumina-supported solvent-free synthesis of various 4-iminothiazolines by condensation of disymmetric thioureas and a-chloro ketone (Scheme 10). The experiments... 

Active heterogeneous catalysts have been obtained. Examples include titania-, vanadia-, silica-, and ceria-based catalysts. A survey of catalytic materials prepared in flames can be found in [20]. Recent advances include nanocrystalline Ti02 [24], one-step synthesis of noble metal Ti02 [25], Ru-doped cobalt-zirconia [26], vanadia-titania [27], Rh-Al203 for chemoselective hydrogenations [28], and alumina-supported noble metal particles via high-throughput experimentation [29]. 

A recent publication by the group of Barbarella has disclosed the rapid preparation of poorly soluble unsubstituted and modified a-quinque- and sexithiophenes by the extensive use of bromination/iodination steps and microwave-assisted Suzuki and Sonogashira cross-couplings (Scheme 6.16) [42]. Suzuki reactions were either carried out under solvent-free conditions on a strongly basic potassium fluoride/ alumina support for the synthesis of soluble oligothiophenes, or in solution phase for the preparation of the rather insoluble a-quinque- and sexithiophenes. In both cases, 5 mol% of [l,l -bis(diphenylphosphino)ferrocene]dichloropalladium(II)... 

Huang, X. W., Elbashir N. O., and Roberts, C. B. 2004. Supercritical solvent effects on hydrocarbon product distributions from Fischer-Tropsch synthesis over an alumina-supported cobalt catalyst. Industrial Engineering Chemistry Research 43 6369-81. 

Ma, W.P., Jacobs, G., Sparks, D.E., Spicer, R.L., Graham, U.M., and Davis, B. H. 2008. Comparison of the kinetics of the Fischer-Tropsch synthesis reaction between structured alumina supported cobalt catalysts with different pore size. Prepr. Am. Chem. Soc. Div. Petro. Chem. 53 99-102. (see Chapter 8 of this book.)... 

Figure 4. Differential spectra of CO chemisorbed on alumina-supported Ni particles both before and after heating to 425 K. Very little surface hydrocarbon is seen to form on the Ni particles. This lack of surface hydrocarbon reflects the selectivity of such catalysts for methanation over Fisher-Tropsch synthesis.

Another study on the preparation of supported oxides illustrates how SIMS can be used to follow the decomposition of catalyst precursors during calcination. We discuss the formation of zirconium dioxide from zirconium ethoxide on a silica support [15], Zr02 is catalytically active for a number of reactions such as isosynthesis, methanol synthesis, and catalytic cracking, but is also of considerable interest as a barrier against diffusion of catalytically active metals such as rhodium or cobalt into alumina supports at elevated temperatures. 

X. Huang, N. O. Elbashir and C. B. Roberts, Supercritical Solvent Effects on Hydrocarbon Product Distributions from Fischer-Tropsch synthesis over an Alumina-Supported Cobalt Catalyst, Ind. Eng. Chem. Res., 2004, 43, 6369-6381. 

Another large class of chemicals produced starting from ethanol are ethyl-amines. When heated to 150-220 °C over a silica- or alumina-supported nickel catalyst, ethanol and ammonia react to produce ethylamine. Further reaction leads to diethylamine and triethylamine. The ethylamines find use in the synthesis of pharmaceuticals, agricultural chemicals, and surfactants. 

Catalysts employed in this study are zirconium(lV)-hydrides on oxide support (silica, silica-alumina and alumina). Their synthesis is described above. We present here some transformations or modifications of polystyrene, linear alkanes and polyethylene with Zr-H catalyst... 

Dioxins, 1,4-oxathiins, and 1,4-dithiins have often been prepared by elimination reactions from saturated analogs as described in CHEC-II(1996) <1996CHEC-II(6)447>. Since then, a synthesis of tetramethyl l,4-dithiin-2,3,5,6-tetracarboxylate 241 has been reported in low yield (12%) by thermal decomposition of the 1,4,2,5-dithiadiazine system 240 in refluxing o-dichlorobenzene in the presence of DMAD <1997J(P1)1157>. Recently, 2,6-divinyl-l,4-dithiin 68 has been isolated from the reaction of l,4-bis(4-bromobut-2-ynyloxy)benzene with an excess of alumina-supported sodium sulfide. The formation of 68 has been presumed to take place via cyclic sulfide 242 <2003S849>. 

Although the synthesis and catalytic activity of unsupported and alumina-supported molybdenum nitride have been studied extensively, much less attention has been given to examining the surface structure and... 

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