563-78-0Relevant articles and documents
REACTIONS OF DIMETHYLBUTENES ON NICKEL-EXCHANGED AND ZINC-EXCHANGED 13X-TYPE ZEOLITES
Moller, Bernard W.,Kemball, Charles,Leach, H. Frank
, p. 453 - 466 (1983)
Reactions involving 3,3-dimethylbut-1-ene (I), 2,3-dimethylbut-1-ene (II) and 2,3-dimethylbut-2-ene (III), including isomerization and exchange with D2 or D2O, have been studied on zinc-exchanged and nickel-exchanged X-type zeolites.The effect of various pretreatments (with hydrogen, carbon monoxide or oxygen) was examined with NiX (21percent exchanged) which, unlike the ZnX zeolites, was a catalyst for the hydrogenation of the C6 alkenes.The acid-catalysed isomerization of I (to II and III) occured on both ZnX and NiX and the activity of the zeolites increased sharply with M2+ ion content.With ZnX(21) or NiX(21) inclusion of H2O or D2O (which gave exchanged products) in the reaction mixture enhanced the rate of isomerization of I, presumably by the creation of more Bronsted acidity.Hydrogenation activity was found only with NiX and was attributed to the reduction of some of the accessible Ni2+ ions by the alkene + hydrogen mixture to Ni+ or possibly Ni0.Treatment with carbon monoxide or oxygen demonstrated the dual-function behaviour of NiX(21), not influencing the acidic catalysis but inhibiting almost completely the hydrogenation activity.
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McLain,S.J. et al.
, p. 5451 - 5453 (1979)
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CATALYTIC PROPERTIES OF EIVB-SUBSTITUTED TUNGSTEN CARBONYL COMPLEXES (EIVB=Ge, Sn) IMMOBILIZED ON A SILICA SUPPORT
Linthoudt, J. P. van,Delmulle, L.,Kelen, G. P. van der
, p. 39 - 48 (1980)
The catalytic activity in olefin disproportionation of a 3,3-dimethyl-1-butene substrate has been investigated for a series of EIVB-W(CO)3C5H5 species (EIVB=Ge, Sn) chemically bonded to a high surface silica carrier.Different product distributions and conversion factors were obtained by thermal and UV activation of the catalysts, whereas variation of the EIVB element had little effect.In all cases, isomerization was observed rather than disproportionation, probably because of steric interaction between the rather bulky t-Bu groups at the active W sites.
Solid-State 1H MAS NMR Study on the Highly Active Protons in Partially Reduced Ag3PW12O40
Baba, Toshihide,Nomura, Mamoru,Ono, Yoshio,Ohno, Yo-ichi
, p. 12888 - 12893 (1993)
The physicochemical nature of protons generated by the partial reduction of Ag+ cations in Ag3PW12O40 with hydrogen was investigated by means of 1H MAS NMR.When Ag3PW12O40 was partially reduced with hydrogen, the 1H MAS NMR spectrum demonstrated the generation of two kinds of acidic protons, which are observed at 6.4 and 9.3 ppm.The protons at 6.4 ppm exist only in the presence of hydrogen in the gas phase.The amount of these protons reversibly changes with the hydrogen pressure.In contrast, the amount of protons at 9.3 ppm is independent of the hydrogen pressure.The amount of protons at 6.4 and 9.3 ppm depended on the degree of the reduction of Ag+ cations in Ag3PW12O40.When the degree of the reduction of Ag+ was 13 percent, the protons at 6.4 ppm were mainly observed and the protons at 9.3 ppm were only slightly observed.The amount of protons at 6.4 ppm increased by increasing the degree of the reduction of Ag+ cations from 13 percent to 32 percent.These protons were scarcely observed when the degree of reduction of Ag+ cations reached 67 percent.In contrast, the amount of protons at 9.3 ppm increased by increasing the degree of reduction of Ag+ cations from 13 percent to 67 percent.The acid strength of the protons observed at 6.4 ppm is higher than that of the protons at 9.3 ppm.The catalytic activity of partially reduced Ag3PW12O40 for the isomerization of 3,3-dimethylbut-1-ene and hexane reversibly changes with hydrogen pressure.
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Smith,Eastman
, p. 4274 (1961)
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Studies on Nickel-Containing Ziegler-Type Catalysts. IV. Dimerization of Propylene to 2,3-Dimethylbutenes. Part-II
Sato, Hiroshi,Tojima, Hideto
, p. 3079 - 3084 (1993)
A small amount of water was found to increase the activity of catalyst (A) for the selective dimerization of propylene to 2,3-dimethylbutenes (DMBS), Ni(naph)2/AlEt3/PR3/Diene/Chlorinated phenol, (A) where Ni(naph)2 denotes nickel naphthenate. The activity increased by about three to five times upon the addition of H2O in amounts of 0.2 to 0.8 mole per mole of AlEt3; the maximum activity was obtained at around 0.5 molar ratio of H2O to AlEt3. On the other hand, the reaction product between H2O and AlEt3 in a molar ratio of 0.5 was isolated and was identified to be μ-oxo-bis(diethylaluminum), the accelerating effect of which was also proved to be high. It is, therefore, concluded that the Lewis acidity of μ-oxo-bis(diethylaluminum) activates the Ni-H bond of the active species through coordination to the square-planar complex of nickel.
Studies on Nickel-Containing Ziegler-Type Catalysts. III. Dimerization of Propylene to 2,3-Dimethylbutenes. Part-I
Sato, Hiroshi,Noguchi, Takanobu,Yasui, Seimei
, p. 3069 - 3078 (1993)
A new selective catalyst was developed for the dimerization of propylene to 2,3-dimethylbutenes (DMBS). It comprises five components: nickel naphthenate (Ni(naph)2)/AlEt3/PR3/diene/chlorinated phenol. Among them, chlorinated phenol is an essential component for activating the catalyst. Both the dimerization of propylene and the isomerization of the produced 2,3-dimethyl-1-butene (DMB-1) to 2,3-dimethyl-2-butene (DMB-2) are accelerated in proportion to the content of the chlorinated phenol as well as to the number of chlorine atoms on the chlorinated phenol. These effects are attributed to the Lewis acidity of the reaction product between AlEt3 and the chlorinated phenol. Thus, either DMB-1 or DMB-2 can be produced selectively by controlling the composition of the catalyst. The content of DMBS mainly depends upon the phosphine ligand; this ligand effect is discussed in terms of the 31P NMR chemical shift. A high content of DMBS of up to 85percent in propylene dimers was attained when phosphines with chemical shifts between 0 and -30 ppm were used.
Experimental and Computational Studies of Palladium-Catalyzed Spirocyclization via a Narasaka-Heck/C(sp3or sp2)-H Activation Cascade Reaction
Wei, Wan-Xu,Li, Yuke,Wen, Ya-Ting,Li, Ming,Li, Xue-Song,Wang, Cui-Tian,Liu, Hong-Chao,Xia, Yu,Zhang, Bo-Sheng,Jiao, Rui-Qiang,Liang, Yong-Min
supporting information, p. 7868 - 7875 (2021/05/27)
The first synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem Narasaka-Heck/C(sp3 or sp2)-H activation reaction is reported here. The key step in this transformation is the activation of a δ-C-H bond via an in situ generated σ-alkyl-Pd(II) species to form a five-membered spiro-palladacycle intermediate. The concerted metalation-deprotonation (CMD) process, rate-determining step, and energy barrier of the entire reaction were explored by density functional theory (DFT) calculations. Moreover, a series of control experiments was conducted to probe the rate-determining step and reversibility of the C(sp3)-H activation step.
Method for preparing 2,3-dimethyl-1-butene by dimerization of propylene
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Paragraph 0026-0065, (2019/07/29)
The invention provides a method for preparing 2,3-dimethyl-1-butene by dimerization of propylene. According to the method, a catalytic system comprises a catalyst, a cocatalyst and a ligand, wherein the ligand is organic phosphorus. The method disclosed by the invention has relatively high selectivity and catalytic activity on 2,3-dimethyl-1-butene. The catalytic system can keep lower reaction temperature and lower reaction pressure (compared with the temperature and pressure of an isomerization process in the prior art), the conditions are mild, the safety coefficient is relatively high, production requirements can be met by general chemical production equipment, and the method is suitable for amplifying production. The catalyst is simple to prepare and is low in cost and good in stability. The catalyst is easier to separate from a reaction system by adopting a metal nickel simple substance for loading, and catalytic active components are not lost easily.
