Catalytic removal

Catalytic removal of diesel soot particulates over LaMnOs perovskite-type oxides... 

In fact, the selective catalytic removal of NO in presence of excess oxygen remains a challenge. Most of the cunent studies involve C1-C4 hydrocarbons as reductants and zeolites as catalysts, among which Cu-exchanged MFI zeolites are considered as one of the most active [2]. The reductant shows a complex influence in this reaction it has been thus reported that a Cu/Zr02 catalysts are active with pro-pene but show low activity with propane as reductant [3]. For a practical use reduction by higher alkanes would be attractive, siiKe it would be easier to handle in a vehicle. 

Intracellular H2O2 is catalytically removed by catalase. The enzyme contains Fe(III) at its active site and is found in the cytosol of erythrocytes as well as the mitochondria and peroxisomes of most other cells. The concentration of catalase in rheumatoid synovial fluid is extremely low and may only be present as a result of erythrocyte lysis. 

Catalytic removal. In this process, lead sulfide serves as the catalyst for the following reaction when the oil is treated with sodium hydroxide ... 

Interest in the adsorption of sulfur-containing molecules at metal surfaces been stimulated by a desire to elucidate the decomposition mechanisms of thiols during the catalytic removal of sulfur from feedstocks and the position of thiols as the favoured head groups for adsorbates used to construct self-assembled monolayers. We shall not survey the extensive self-assembled film literature but restrict our discussion to the simpler thiols. 

For similar motivations, there are limited incentives to develop an alternative SCR process for stationary sources based on methane (CH4-SCR) or other HCs, or based on NTP technologies, if not for specific, better applications. The situation is instead quite different for mobile sources, and in particular for diesel engine emissions. The catalytic removal of NO under lean conditions, e.g. when 02 during the combustion is in excess with respect to the stoichiometric one (diesel and lean-burn engines, natural gas or LPG-powered engines), is still a relevant target in catalysis research and an open problem to meet future exhaust emission regulations. 

Peng, X., Lin, H., Huang, Z. et al. (2006) Effect of catalysis on plasma assisted catalytic removal of nitrogen oxides and soot, Chem. Eng. Technol. 29, 1262-6. 

Gondal MA, Seddiqi Z (2006) Laser-induced photo-catalytic removal of phenol using n-type WO3 semiconductor catalyst. Chem Phys Lett 417 124-127... 

Gondal MA, Sayeed MN, Seddiqi Z (2008) Laser enhanced photo-catalytic removal of phenol from water using p-type NiO semiconductor catalyst. J Hazard Mater 155 83-89... 

Ever since the first study of metal-exchanged zeolites as new catalysts for selective catalytic reduction (SCR) of NOx with methane in the presence of oxygen was undertaken (Li and Armor, 1993), the simultaneous catalytic removal of NOx and CH4 at the exhaust of lean-bum natural gas engines has remained a challenge. 

The catalytic RCM with 31 as substrate (Scheme 7) is significantly more facile when the reaction is carried out under an atmosphere of ethylene, presumably due to the formation of the more active Mo=CH2 system (see below for further details). Thus, after catalytic removal of the directing unit, the chiral unsaturated alcohol (S)-32,the formal product of an enantioselective addition of the Grignard reagent to unfunctionalized heterocycle 33, is obtained. An additional in-... 

Technically, ethylene is obtained from alcohol by catalytic removal of water with alumina heated to 200°-300° (Senderens). The alcohol vapour is led over the hot material.1 For the preparative application of such reactions aluminium phosphate is as suitable as alumina. 

The Delft synthesis makes use of an acid-catalyzed ring closure - in fact an intramolecular aromatic alkylation - of a l-(3,5-dihydroxy-4-methoxybenzyl) isoquinoline derivative that is prepared starting from (natural) gallic acid. One of the hydroxyl groups is removed via a Pd/ C hydrogenation of the benzyl ether. Other catalytic steps play an important role some steps were improved recently [27]. The crucial step in the Rice synthesis makes use of a l-(2-bromo-5-hydroxy-4-methoxybenzyl)isoquinoline derivative that is also cyclized in an acid-catalyzed ring closure to the morphinan skeleton, followed by catalytic removal of the bromo substituent (Scheme 5.8). 

Hydrode- sulfurization Treatment Catalytic Remove sulfur, contaminants High-sulfur residual/gas oil Desulfurized olefins... 

Hydrotreating Hydrogenation Catalytic Remove impnrities, satnrate HCs Residuals, cracked HCs Cracker feed, distillate, lube... 

Sweetening Treatment Catalytic Remove H2S, convert mercaptan Untreated distillate/gasoline High-quality distillate/gasoline... 

As with sweetening the design process for removal of CO2 is very similar to that of dehydration. Special consideration is given to the presence of O2 in the feed and in some cases it is found necessary to catalytically remove the oxygen. 

The starting diol was transformed into the dibromide by elemental bromine with triphenyl phosphine adduct which undergoes the Arbuzov-Michaelis reaction under somewhat drastic conditions at 150 °C (step a). Catalytic removal of the benzyl group was performed by a Pd/C catalyst (step b) and the alcohol formed was allowed to react with dichloropurine in the presence of triphenylphosphine and diethylazodicarboxylate (Mit-sunobu reaction) (step c). Finally the desired product was obtained by reaction with methylamine (step d) and the removal of ethyl groups at the phosphorus centre was performed by transilylation using trimethyliodosilane (step e). 

Catalytic Removal of NO Under Lean Conditions from Stationary and Mobile Sources... 

J3 Catalytic Removal of NO., Under Lean Conditions from Stationary and Mobile Sources between ammonia and NO in adsorbing on the catalyst) [56] ... 

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