61434-46-6Relevant articles and documents
The isopropylation of biphenyl over transition metal substituted aluminophosphates: MAPO-5 (M: Co and Ni)
Zhang, Hui Xing,Chokkalingam, Anand,Subramaniam, Priya V.,Joseph, Stalin,Takeuchi, Seiji,Wei, Ming Deng,Al-Enizi, Abdullah M.,Jang, Hoi-Gu,Kim, Jong-Ho,Seo, Gon,Komura, Kenichi,Sugi, Yoshihiro,Vinu, Ajayan
, p. 117 - 124 (2016/01/26)
The isopropylation of biphenyl (BP) was examined over transition metal substituted aluminophosphates (MAPO-5; M: Co and Ni) with 12-membered (12-MR) oxygen ring pore-entrances of AFI topology. The MAPO-5 samples were synthesized by dry gel conversion method using trimethylamine as a structure directing agent, and their properties were characterized by XRD, XPS, SEM, N2 adsorption, NH3-TPD, pyridine adsorption, and o-xylene uptake. They are clear crystals without impurity phases and agglomerates, and found small amounts of Br?nsted acid sites which are expecting active for acid catalysis. The isopropylation of BP over both of Co(5)APO-5 and Ni(5)APO-5 at 250 °C gave the high selectivities for 4,4′-DIPB: 65-75%. 4-IPBP is almost exclusive precursor of 4,4′- and 3,4′-DIPB. 3-IPBP was not significantly concerned even though 3-IPBP was predominant among IPBP isomers at the late stages: the MAPO-5 channels allow preferential access of 4-IPBP, and prevent the access of 3-IPBP due to reactant selectivity mechanism. The selective formation of 4,4′-DIPB occurred by preferential exclusion of bulkier 3,4′-DIPB and other isomers through the steric interaction of transition states with the channels by the restricted transition state selectivity mechanism. MAPO-5 (M: Co and Ni) has the same level of the selectivities for 4,4′-DIPB to SSZ-24 and other MAPO-5 (M: Si, Mg, and Zn), and these selectivities were originated by the AFI channels. The selectivities for 4,4′-DIPB were kept 65-75% at low and moderate temperatures over MAPO-5 (M: Co and Ni); however, they were decreased by the isomerization to stable 3,4′-DIPB with the increase in temperature.
Isopropylation of biphenyl over ZSM-12 zeolites
Chokkalingam, Anand,Kawagoe, Hiroaki,Watanabe, Seiji,Moriyama, Yasuhiro,Komura, Kenichi,Kubota, Yoshihiro,Kim, Jong-Ho,Seo, Gon,Vinu, Ajayan,Sugi, Yoshihiro
, p. 23 - 30 (2013/02/23)
ZSM-12 zeolites, ZSM-12L and ZSM-12S, with MTW topology were synthesized by using methyltriethylammonium bromide (MTEABr) and tetraethylammnoium bromide (TEABr) as structure directing agents (SDA), respectively, for the isopropylation of biphenyl (BP) usi
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.