Magic acid catalyst

The high acidity of superacids makes them extremely effective pro-tonating agents and catalysts. They also can activate a wide variety of extremely weakly basic compounds (nucleophiles) that previously could not be considered reactive in any practical way. Superacids such as fluoroantimonic or magic acid are capable of protonating not only TT-donor systems (aromatics, olefins, and acetylenes) but also what are called (T-donors, such as saturated hydrocarbons, including methane (CH4), the simplest parent saturated hydrocarbon. 

Nuclear magnetic resonance (NMR) is another powerful technique to study solid acid catalysts. Advanced NMR methods such as magic-angle spinning (MAS) of solids have increased the capability of this technique to study acid sites in solid acid catalysts [80]. For example, H MAS NMR technique performed on the solid catalysts after activation and upon adsorption allows the detection of the signals due to the magnetic resonance of the protons... 

In discussing superacids as catalysts for chemical reactions, we will review both liquid (Magic Acid, fluoroantimonic acid, etc.) and solid (Nafion-H, etc.) acid-catalyzed reactions, but not those of conventional Friedel-Crafts-type catalysts. The latter reactions have been extensively reviewed elsewhere (see G. A. Olah, Friedel-Crafts Chemistry, Wiley, New York, 1972 G. A. Olah, ed., Friedel-Crafts and Related Reactions, Vols. I-IV, Wiley-Interscience, New York, 1963-1965). 

A comparison of the reactivity of SbF5-treated metal oxides with that of HS03F-, SbCl5-, and HS03F-SbF5 (magic acid)-treated catalysts showed that the former was by far the best catalyst for reaction of alkanes (31, 32). Tracer studies of conversion of alkanes catalyzed by the superacids were performed it was suggested that the reactions proceeded by carbenium ion mechanisms in which the reactions were initiated by abstraction of H from the reactants (33). 

In-Sitii C NMR Studies of 1-Butene Reactions on Acid Catalysts without Magic Angle Spinning... 

The "liquid state" in-situ NMR studies made here probe the reactions of physisorbed, and possibly in part chemisorbed, species. NMR studies of olefins adsorbed on acidic catalysts have difficulty evidencing the olefinic nature of the initial chemisorbed species [2,6,7]. This is probably because they are short-lived (e g. carbenium ions) or have poor spectroscopic properties (e g. broad lines). These problems are not resolved by magic angle spinning and solid state methods. 

The carbonylation of olefins, by using such strong acids such as H2SO4, H3PO4-BF3, or HF-SbFs (superacids or magic acids) as catalysts, is known as the Koch synthesis. It 3delds predominantly branched isomers of carboxylic acids Neo acids (Exxon) and Versatic acids (Shell). The economic importance of these products is far less than that of the compovmds obtained by Reppe reactions (85,86). 

Magic angle spinning-nuclear magnetic resonance (MAS NMR) spectroscopy has become in the last ten years or so one of the most powerful techniques for the investigation of sohd acid catalysts [38,39]. 

Benzylidene acetals can be formed under essentially neutral conditions using the bis-sulphonium ion (62) obtained by methylation of benzaldehyde ethylene dithioacetal with methyl fluorosulphonate (Magic Methyl ). Thus, methyl -d-glucopyranoside afforded a 4,6-0-benzylidene derivative (25%) when treated with (62) in pyridine. In the absence of an acid catalyst, it is unlikely that the thermodynamically favoured acetal would be obtained in high yield. 

To the present day there is an ongoing search for the magic additive which allows molar mass control of Nd-catalyzed polymerizations without a detrimental effect on polymerization activities. This search is documented in the scientific as well as in the patent literature. In this context ethanol, dihydronaphthaline, chloroform, diethyl aniline, triphenylmethane, octanoic acid, allyl iodide and diallylether were unsuccessfully evaluated [464,465]. Also propylene, oxygen, 1,5-hexadiene, ethyltrichloroacetate and n-butanol resulted in the deactivation of the catalyst system without the desired reduction of molar mass [157]. 

Enzymes are proteins that catalyze biochemical reactions. A catalyst is a substance that greatly accelerates the rate of a particular reaction without being used up or permanently altered- In the real world, most catalysts eventually deteriorate and no longer function as a catalyst. In the cell, all enzymes are eventually degraded and converted back to their constituent amino acids plus, in some cases, byproducts of oxidation or other types of damage- Ptoteins do not have some unique magical property that allows them to function as enzymes. For certain activities nucleic acids also participate in the chemistry of catalysis- For example, mRNAcan catalyze certain types of RNA splicing. 

Inl989, Yamamoto introduced the chiral (acyloxy)borane (CAB) complex for catalytic asymmetric Diels-Alder reactions [18], which has been utilized as a magic hand catalysis for the aldol synthesis and for the Sakurai-Hosomi reaction so far [19,20]. In contrast to R=H of 17, which is both air and moisture sensitive, the B-alkylated catalyst, R=Ph or alkyl, is stable and can be stored in closed containers at room temperature. This catalyst is easily prepared from phenyl- or alkylboric acid and 16 simple mixing of a 1 1 molar ratio of the ester 16 and phe-... 

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