- Metal cation-exchanged montmorillonite (Mn+-mont)-catalysed aromatic alkylation with aldehydes and ketones
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The alkylation of aromatic compounds with aldehydes and ketones in the presence of a variety of metal cation-exchanged montmorillonites (Mn+-mont; Mn+ = Zr4+, Al3+, Fe3+, Zn2+, H+, Na+) has been investigated. Al3+- and Zr4+-Monts are revealed to be effective as catalysts, while no reaction takes place with Na+-mont. Al3+-Mont-catalysed alkylation of phenol with several aldehydes produces mainly or almost solely the corresponding gem-bis(hydroxyphenyl)alkanes (bisphenols) in good yields, while that with several ketones affords selectively the corresponding alkylphenols in moderate to good yields. The alkylation always occurs at the carbonyl carbon without any skeletal rearrangement and the kind of products depends much on the steric hindrance of an electrophilic intermediary carbocation. The alkylation of anisole, veratrole and p-cresol proceeds well, while that of toluene, benzene, chlorobenzene and nitrobenzene scarcely occurs.
- Tateiwa, Jun-Ichi,Hayama, Ei,Nishimura, Takahiro,Uemura, Sakae
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p. 1923 - 1928
(2007/10/03)
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- Equilibria for the isomerization of (secondary-alkyl)phenols and cyclohexylphenols
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Equilibria of a series of isomerizations and trans-alkylations of alkylphenols have been investigated in the liquid phase over a wide range of temperatures.Equilibria of isomerizations connected with the displacement of a substituent on a benzene nucleus were studied for secondary-butyl, -amyl, -hexyl, and cyclohexyl-phenols, and di-(secondary-butyl)phenols.Equilibria of positional isomerization connected with the displacement of an oxyphenyl radical in an alkyl chain were investigated for oxyphenyl-pentanes, -hexanes, -octanes, and -decanes.Trans-alkylation was investigated for di- and tri-(secondary-butyl)phenols.Values of ΔrH0m and ΔrS0m were found for all investigated reactions.An analysis was made of the thermodynamic quantities for the reactions.Enthalpies of formation of isopropylphenols (IPP) in the gaseous state were calculated.The values of ΔfH0m/(kJ * mol-1) were found at 298.15 K: o-IPP, -(175.3 +/- 2.4); p-IPP, -(175.3 +/- 2.4); m-IPP, -(175.3 +/-2.4); 2,4-di-IPP, -(254.1 +/- 2.8); 2,5-di-IPP, -(254.1 +/- 2.8); 2,6-di-IPP, -(254.1 +/- 2.8); 3,5-di-IPP, -(254.1 +/- 2.8); 2,4,6-tri-IPP, -(333.0 +/- 3.1).
- Nesterova, T. N.,Pimerzin, A. A.,Rozhnov, A. M.,Karlina, T. N.
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p. 385 - 396
(2007/10/02)
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- Nucleophilic Displacement with Heterocycles as Leaving Groups. Part 16. Reactions of Secondary Alkyl Primary Amines with 5,6,8,9-Tetrahydro-7-phenyldibenzoxanthylium Trifluoromethanesulphonate to give Intermediates Solvolysing without Rearrangement
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Representative secondary alkyl primary amines R1R2CHNH2 react with the title pyrylium cation in acetic acid, alcohols, phenols, and NN-dimethylaniline acting as nucleophilic solvents to give O- and C-(secondary alkyl) products.Absence of carbenium ion rearrangements is consistent with reaction via intimate ion-molecule pairs formed rapidly from the corresponding pyridinium cations.
- Katritzky, Alan R.,Lopez-Rodriguez, Maria L.,Keay, James G.,King, Roy W.
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p. 165 - 170
(2007/10/02)
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