36919-89-8Relevant academic research and scientific papers
The alkylation of biphenyl over one-dimensional twelve-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for 4,4'-dialkylbiphenyl
Sugi, Yoshihiro,Maekawa, Hiroyoshi,Ito, Akira,Ozawa, Chikako,Shibata, Tomoko,Niimi, Amhiro,Asaoka, Chihara,Komura, Kenichi,Kubota, Yoshihiro,Lee, Jae-Youl,Kim, Jong-Ho,Seo, Gon
supporting information; body text, p. 2232 - 2242 (2009/08/08)
Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of biphenyl (BP) was examined over one-dimensional twelve-membered (12-MR) zeolites: Mordenite (MOR) and SSZ-24 (AFI) with straight channels, and SSZ-55 (ATS) and SSZ-42 (IFR) with corrugated channels. Types of zeolites and alkylating agents highly influenced the selectivities for dialkylbiphenyl (DABP) isomers. Shape-selective formation of 4,4'-diisopropylbiphenyl (4,4'-DIPB) was observed over MOR and AFI; however, ATS and IFR gave 4,4'-DIPB only in low selectivities at 250°C: 87% over MOR, 60% over AFI, 20% over ATS, and 30% over IFR. The selectivities for 4,4'-di-s-butylbiphenyl (4,4'-DSBB) in the,s-butyl-ation were higher than those for 4,4'-DIPB: 95% over MOR, 85% over AFI, 75% over ATS, and 50% over IFR. The t-butylation afforded selectively 4,4'-di-t-butylbiphenyl (4,4'-DTBB) over the zeolites: 96-97% over MOR and AFI, 90% over ATS, and 80% over IFR. These results in the alkylation indicate the exclusion of 4,4'-DABP from other bulky DABP isomers by steric restriction in zeolite channels is an important key for the high shape-selectivity. Even zeolites with large channels, such as ATS and IFR, can have shape-selective nature if the bulky moieties, such as,s-butyl and t- butyl groups, are large enough to differentiate the transition state of the least bulky 4,4'-DABP from those of the other isomers inside their channels. The selectivity for 4,4'-DABP decreased at high temperatures in some alkylations: isopropylation over MOR, and s-butylation and t-butylation over MOR, AFI, and ATS. The decreases are due to the iso-merization of 4,4'-DABP at external acid sites, because the channels are not large enough for the isomerization of 4,4'-DABP to bulkier 3,4'-DABP. However, the isopropylation over AFI was accompanied by the isomerization of 4,4'-DIPB at external and internal acid sites, because the channels are large enough for the isomerization of 4,4'-DIPB.
METHOD FOR THE PREPARATION OF A COMPOUND OF THE GENERAL FORMULA R1-R1 AND/OR R1-R2 USING HOMO AND HETERO COUPLING REACTIONS
-
Page/Page column 17-18, (2010/11/29)
The present application relates to a method for the preparation of a compound of the general formula R1-R2 (I) and/or R1-R1 (II) comprising providing a compound of the general formula R1dM1Am.zM4Zn (III) or R1R2M1R3kAm.xM4Zn (IV) or R1M1R2R3kM2Am.xM4Zn (V) or R1M3R2M1.xM4Zn (VI) and reacting this compound III-VI with a quinone to produce a compound of the general formula (I) or (II) or a mixture of compounds (I) and (II). The coupling reaction can be used to prepare homo and/or hetero coupling products from well known starting materials using a quinone as redox reagent. The quinone may be recycled from the reaction.
Transition-metal-free homocoupling of organomagnesium compounds
Krasovskiy, Arkady,Tishkov, Alexander,Del Amo, Vicente,Mayr, Herbert,Knochel, Paul
, p. 5010 - 5014 (2007/10/03)
(Chemical Equation Presented) Without palladium or copper: A wide range of functionalized Grignard compounds were coupled by using diphenoquinone 1 as an electron acceptor. The oxidative dimerization of alkenylmagnesium reagents proceeds with complete retention of the stereochemistry (see scheme; TBDMS = tert-butyldimethylsilyl).
