31603-95-9

The alkylation of solid 4-tertiobutylphenol by gaseous isobutene in the presence of a catalyst has been studied according to different parameters such as, temperature, initial pressure of isobutene, proportion of catalyst and the granulometry of the catalyst and the solid reactant. Among the predefined kinetic models, the unreacted core model for spherical particles of unchanging size is the best adapted to the experimental results. Based on this model, a mechanism is proposed involving the intervention of a carbocation.

A mild and nonreversible tert-butylation of alcohols and phenols can be achieved in high yields using the noncoordinating acid-base catalyst [bis(trifluoromethane)sulfonimide and 2,6-lutidine] with a tert-butylation reagent, tert-butyl 2,2,2-trichloroacetimidate. This method allows the use of substrates containing acid sensitive groups such as ketal, Boc, and boronate esters.

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A number of (S)-(-)-2-amino-1,1-diaryl-1-propanol compounds have been synthesized. They were used to form the binuclear copper complexes through a spontaneous assembly of the individual components, the β-aminoalcohol, 2- hydroxy-5-methyl-1,3-benzenedialdehyde, and copper acetate monohydrate, in methanol. These binuclear complexes were examined as asymmetric catalysts for cyclopropanation of styrene by ethyl diazoacetate. Moderate improvement in enantioselectivity has been observed for the binuclear versus mononuclear copper complexes. The e.e. values up to 87% for trans and 93% for cis products and the ratio between trans and cis products up to 9:1 have been obtained.

Pd/P(t-Bu)3 catalyzed reaction of aryl halides with sodium t-butoxide effectively to give aryl t-butyl ethers. The high catalytic activity realized the formation of aryl t-butyl ethers from not only electron-deficient aryl halides but also electron-rich aryl halides. Moreover, the first synthesis of 4-chlorobenzofuran was attained utilizing the selective mono-t-butoxylation of aryl dihalide.

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A method for preparing an aryl ether compound is provided in which an alcohol is reacted with an aromatic compound in the presence of a base, and a transition metal catalyst selected from the group consisting of platinum and nickel to form an aryl ether.

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We report the nickel-catalyzed formation of alkyl and silyl ethers from aryl halides in one step. These ethers can act as precursors to phenols by reaction with Bronsted or Lewis acids or with fluoride. A combination of Ni(COD)2 and DPPF mediates the formation of tert-butyl aryl, methyl aryl, and tert-butyldimethyl silyl aryl ethers efficiently from aryl halides and sodium alkoxides or sodium siloxides under mild reaction conditions. Reactions to form the tert-butyl aryl ethers mediated by nickel complexes have lower turnover numbers than the analogous palladium-catalyzed reactions. However, reactions to form methyl aryl ethers show higher yields when catalyzed by a combination of Ni(COD)2 and BINAP than when catalyzed by BINAP or DPPF and palladium catalyst precursors. Similarly, the formation of silyl aryl ethers occurs in higher yields and under milder conditions when catalyzed by a combination Ni(COD)2 and DPPF than when catalyzed by palladium complexes. We also report improved yields from our previous results for the palladium-catalyzed conversion of aryl halides to tert-butyl aryl ethers.

Pinacolone photolysis in the presence of phenols leads to phenyl acetates and hydroxy acetophenones; Norrish type I cleavage and subsequent hydrogen abstraction from the phenol by the tert-butyl radical gives rise to acyl-aryloxy radical pairs which recombined constituting an intermolecular photo-Fries rearrangement.

Organic solid/gas reactions.Alkylation of 4-tert-butylphenol by isobutene gas in the presence of solid or liquid catalysts.Study of the reaction parameters.Alkylation of phenols was studied in the solid phase in the presence of acid catalysts.The solid 4-tert-butylphenol was alkylated by gaseous isobutene under mild conditions in a batch reactor, tubular reactor and fixed-bed reactor.The solid 4-tert-butylphenol can be used in three ways: directly in its initial solid state; supported on silica or alumina; or deposited on a solid catalyst.The reaction arises from three reactive phases, each of which was characterized.The effect of followed parameters was studied: temperature; pressure; flow-rate; proportion and nature of the catalyst; contact area and size of reactants and catalysts; and reactor geometry.The modification of the conversion ratio with these parameters allowed us to define the optimum conditions for the gas/solid reactions.The nature and the number of contacts between solid phases are specified; the reaction and the interface are localized.The O- and C-alkylation ratio was studied; O-alkylation predominated at low temperature. - Keywords: solid state; alkylation; 4-tert-butylphenol; 2,4-di-tert-butylphenol; tert-butyl-4-tert-butylphenyl ether; catalyst.

Catalyzed alkylation of solid aromatic substances is envisaged.The solid phenol, isobutene gas reaction is carried out in the presence of solid catalysts.Two phosphoric acid and silica based catalysts were prepared and tested.The reactivity and selectivity of the solide phase reaction were determined as a function of the nature and quantity of the catalyst.The results are compared with those of the liquid state and the solution.A mechanism involving transfer of active entities from the solid catalyst to the solid organic reagent is proposed.