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A Highly Selective Synthesis of 1,1′‐Bi‐2‐naphthol by Oxidative Coupling of Naphthol on Mesoporous Fe,Cu/MCM‐41 Aluminosilicates
Author(s) -
Armengol Elvira,
Corma Avelino,
García Hermenegildo,
Primo Jaime
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199908)1999:8<1915::aid-ejoc1915>3.0.co;2-1
Subject(s) - aluminosilicate , zeolite , chemistry , catalysis , mesoporous material , oxidative coupling of methane , selectivity , dissolution , heterogeneous catalysis , molecular sieve , chemical engineering , inorganic chemistry , organic chemistry , engineering
Abstract The oxidative coupling of 2‐naphtol to 2,2′‐dihydroxy‐1,1′‐binaphthyl (binaphthol) by air or oxygen has been carried out in the presence of Cu 2+ ‐ and Fe 3+ ‐doped MCM‐41 aluminosilicate as catalyst. Fe‐exchanged MCM‐41 was found to be a very efficient catalyst; excellent mass balances (> 95%) with almost total conversion and selectivity to binaphthol were achieved. The same reaction has also been carried out on Cu 2+ – and Fe 3+ –Y zeolites. Taking into account the relative dimensions of binaphthol and the catalyst pores, molecular modeling predicts that binaphthol can be accommodated inside the zeolite Y supercages (1.3 nm), but it cannot diffuse outside the zeolite cavities through the smaller pore apertures (0.74 nm). This prediction has been confirmed by dissolving a Y zeolite after the reaction, whereby unextractable binaphthol entrapped within the cavities was recovered. Variable amounts of two secondary by‐products have also been detected, and their structure assigned to (2,8′);(8,2′)‐dioxo‐1,1′‐binaphthyl and bisnaphthofuran based on analytical and spectroscopic data. Their percentage is particularly high when alumina‐supported CuSO 4 is used as the catalyst.