Catalysts identifying

Cheruku et al. have investigated a series of enol esters [73, 95]. A preliminary experiment to determine the optimal protecting group with a small group of catalysts identified diphenylphosphinates as the optimal esters (Table 11). 

In contrast, Pt18Co62Ru20 is an active composition on the Pt-rich side of the activity maximum. A similar stability evaluation reveals relatively stable behavior, as shown in Fig. 11.19. This composition is similar to the original catalyst identified during the broad screening study. Diffraction after screening is substantially similar to that before screening (Fig. 11.19b), and EDX data before and after screening indicate stability (Fig. 11.19 c). 

For the use of bifunctional chiral imino peptide titanium catalysts identified by screening of parallel libraries, see a) C. A. Krueger, K. W. Kuntz, C. D. Dzierba,... 

Three Engelhard FOC catalysts, identified as catalysts A, B, and C representing typical gasoline, partial octane and octane catalysts were prepared for comparing various test methods. Chemical and physical properties are presented in Table 1. 

Based on a most simple analysis, one might approach the design of a metal-im-ido transfer catalyst by considering the corresponding reactivity of metal-carbe-noid complexes or metal-oxo complexes (Fig. 2). It is interesting, in fact, that all of the imido transfer catalysts identified thus far fall into the general category of olefin epoxidation or cycloprop anation catalysts. 

Mn +e Mn +e Mn ), acting in both cases as an active component of the redox system. Structural characterization of unsupported or supported MnO catalysts identified the presence of Mn02 or mixed Mn02/Mn203 as the active catalyst components [1]. 

Two Pd catalysts identified, highly effective for aryl chlorides... 

Chemspeed ASW 2000 3-5 ml, 20-80 °G GC-MS Selective catalyst identified to couple acrylates and aryl amides 2002 64... 

Sealed glass 96-well microtiter plate, 50 pi, 70 "G FRET technique, fluorescence plate reader Catalyst identified to couple cyanoacetate with a variety of aryl halides 2001 59... 

Septa-sealed glass vials on an orbital shaker, 450 pi, 80 °G GG Two high yielding Cu catalysts identified (yields >50%) 2000 66... 

Parallal apparatus installed in glove box GG Multiple high yielding Ni and Pd catalysts identified 2002 67... 

Gustom 60-well teflon plate, 300 pi, RT Colorimetric assay New Pd catalyst identified 1998 71... 

Unexpected outcome, olefin isomerization catalyst identified Ru catalyst identified... 

Hydrogenation of various substrates 20 Planar chiral diphosphines covalently attached to an arene chromium tricarbonyl framework Rh Two Formats (i) glass vials, 1 bar H2, RT, (ii) high pressure 80 bar H2, RT h Several promising new catalysts identified, ee values up to 82% 2004 105... 

Transfer hydrogenation of acetophenone Nine chiral amines Ru 6 ml, RT Capillary GG Several promising new catalysts identified, ee values up to 89% 2005 103... 

Hydroformylation of pooled substrates (styrene, vinyl acetate, and allyl cyanide) Nine chiral phosphites Ru Endeavor eight-well reactod 4 ml, 35 or 100 C, 150 psi 1 1 H2/CO Chiral GC Rh catalyst identified, ee values up to 88% for vinyl acetate (branched/linear ratio >100 1) 2004 114... 

Allylic substitution 1,3-diphenylpropenyl acetate plus dimethylmalonate 13 Phosphine oxazolines Pd Array of 1 ml polypropylene tubes, 430 pi, RT Chiral HPLC Pd catalyst identified, ee values up to 94% 1998 117d... 

Allylic substitution reaction cyclopentenyl acetate plus dimethylmalonate 136 Phosphines bound to /3-turn peptides linked to a solid support Pd Array of vials, 2 ml, RT NMR Pd catalyst identified, ee values up to 95% 2004 117a... 

Allylic substitution reactions chiral allylic esters plus diethylmalonate 60 Phosphorus-based ligands Pd 250 pi, RT ESI-MS Pd catalyst identified with ee values higher than previously reported 2004 82e... 

Hydrosilylation of various ketones 32 Nitrogen-containing chiral phosphites Rh Array of glass vials, 100 pi, RT ESI-MS and chip-based DIOS-MS Pd catalyst identified ee values up to 88% 2003 82e... 

In a subsequent study, the Gibson/BP team further optimized the salicylaldimine chromium catalysts identified in the initial high-throughput screening experiments. The six most active catalysts were first tested at larger scales, and the... 

While the visual appearance of the products was sufficient to identify the active catalysts, the authors employed a parallel UV plate reader to quantify the results. The rhodium catalysts identified provided encouragement that metals other than palladium could be developed for this transformation, and in a subsequent experiment, the colorimetric technique was used to discover the first non-phosphine-based iridium catalyst for allylic alkylations. A high-throughput approach to the discovery of catalysts for asymmetric allylic alkylations is also described in Section 1.13.3.6. 

Zeolites were used in various processes that convert paraffins or olefins into alkyl monoaromatics containing chiefly from six to nine carbon atoms.There are various catalysts, and they involve a base or an acid zeolite, according to the type of process. The first catalyst, identified at the end of the 1970s. is composed of Pt deposited on the L zeolite (Table 2) exchanged with large alkaline ions such as potassium or alkaline earths, such as Ba. which gives it an alkaline nature. This cataiyst is monofunctional and is conceptually different from the conventional bifunctional acid catalysts based on Pt on chlorinated alumina. It selectively dehydrocyclizes the paraffins into aromatics, particularly hexane, which is the least reactive of them. The reaction takes place on the metal, which develops a special selectivity in contact with the alkaline zeolite. This aromatization process has not been successful so far. partly because of the extreme sensitivity of the catalyst to the slightest trace of sulfur compounds. 

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