共查询到20条相似文献,搜索用时 15 毫秒
1.
A thermoregulated phase‐transfer (TRPT) Rh(I) complex catalyst A prepared from Rh(acac)(CO)2 and a thermoregulated ligand CH3(OCH2CH2)mPPh2 (Mw = 918) was applied to the biphasic hydroformylation of 1‐octene, and a high activity with an aldehyde yield of 97.5% was demonstrated. After three recycling steps, the aldehyde yield gradually decreased. Transmission electron microscopy (TEM) revealed that after the first cycle Rh colloids were generated in situ in the aqueous phase, and in subsequent runs Ostwald ripening occurred. An independently prepared colloidal Rh(0) TRPT catalyst D also exhibited high hydroformylation activity under identical experimental conditions, and after two times of recycling an activity decrease was also observed. It is suggested that in situ from Rh(acac)(CO)2 colloidal Rh particles are generated, which demonstrate thermomorphic behaviour and a high hydroformylation activity. Subsequently, agglomeration processes result in an activity decay, as observed in the TRPT Rh(I) complex catalyst system. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
2.
3.
Qingrong Peng Changxi Deng Yong Yang Maohua Dai Youzhu Yuan 《Reaction Kinetics and Catalysis Letters》2007,90(1):53-60
A biphasic catalysis system composed of ionic liquid and rhodium complexes with water-soluble or amphiphilic phosphine ligands
bearing water-soluble groups of sodium sulfonate have been employed for hydroformylation of 1-hexene. The experimental results
show that the activity is almost independent of the hydrotropicity of the phosphine ligands in BMI·BF4. In this system, the extraction of phosphine species by the organics from the IL phase was quite low but larger than that
of rhodium species and showed rather good stability of catalytic activity. A slight decrease in the aldehyde n/i ratio during the catalyst reuse could be recovered, in part, by replenishing certain amount of ligand into the used catalyst
system. 相似文献
4.
The aqueous/organic biphasic hydroformylation of 1‐octene catalyzed by Co2(CO)8/Ph2P(CH2CH2O)nMe, an in situ formed thermoregulated phase‐transfer cobalt catalyst, has been developed. The catalyst activity in this biphasic system was as high as that in the homogeneous system. The yield of oxo‐products was 93% when the reaction was carried out at 180 °C and under 4.0 MPa syngas pressure for 20 h. The catalyst could be easily recovered in the aqueous phase by decanting after the reaction system was cooled, and reused in consecutive reaction without any treatment. The loss of Co in the organic phase was less than 1% on average of five successive runs. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
6.
Xiaoling Luo Dianyong Tang Ming Li 《International journal of quantum chemistry》2006,106(8):1844-1852
A comprehensive theoretical investigation into the mechanism of 1‐phenyl‐1‐(4‐pyridyl)ethene hydroformylation, using a rhodium catalyst employing a nonlocal density functional method (B3LYP), was carried out. The calculated results show that it is strongly exothermic by >90 kJ/mol of the whole catalytic cycle, and the rate‐limited step is H2 oxidative addition. The regioselectivity originates from olefin insertion into the Rh? H bond. The predominant product is the regiospecifically 3‐phenyl‐3‐(4‐pyridal)propanal determined both thermodynamically and kinetically. These are in agreement with practicality experimental studies. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 相似文献
7.
在RhC l(CO)(TPPTS)2-TPPTS-CTAB作为催化剂的水-有机两相催化体系中,详细考察了TPPTS与TPPMS的摩尔比、催化剂浓度、表面活性剂的浓度、搅拌速度等反应条件对1-癸烯氢甲酰化反应活性和区域选择性的影响。研究结果表明:在保持体系中总的膦/铑摩尔比不变的情况下,加入TPPMS对催化活性影响不大,但可明显提高区域选择性。当[TPPTS]/[TPPMS]=1时,表现出较好的协同催化效应,生成醛的正/异比从没加TPPMS时的5.9增加到了11.5。同时,催化剂浓度、表面活性剂的结构和浓度、搅拌速度等反应的活性和区域选择性都有重要影响。 相似文献
8.
Rhodium‐catalysed hydroformylation of 1‐octene using aryl and ferrocenyl Schiff base‐derived ligands
《应用有机金属化学》2017,31(4)
Monometallic and heterobimetallic complexes of Rh(I) bearing chelating N ,O ‐bidentate aryl‐ and ferrocenyl‐derived ligands have been synthesised via Schiff base condensation reactions, and characterised fully using 1H NMR, 13C{1H} NMR and Fourier transform infrared spectroscopies, elemental analysis and mass spectrometry. The new monometallic and heterobimetallic complexes were evaluated as potential catalyst precursors in the hydroformylation of 1‐octene at 95°C and 40 bar. The ferrocenylimine mononuclear compounds were inactive in the hydroformylation experiments. The Rh(I) monometallic and the ferrocene–Rh(I) heterobimetallic pre‐catalysts displayed good activity and conversion of 1‐octene as well as outstanding chemoselectivity towards aldehydes in the hydroformylation reaction. 相似文献
9.
Dimeric rhodium(I) complex [Rh(OMe)(cod)]2 was found to be an active catalyst of phenylacetylene polymerization to poly(phenylacetylene) (PPA) in ionic liquids containing imidazolium or pyridinium cations. The highest yield of PPA (92%) was obtained in 1‐butyl‐4‐methylpyridinium tetrafluoroborate as reaction medium. The yield of PPA in imidazolium ionic liquids containing BF4? or PF6? anions increased to 83–99% when Et3N or cycloocta‐1,5‐diene were added as co‐catalysts. In 1‐methyl‐3‐octylimidazolium chloride (MOI · Cl) polymerization rate was much lower than in other ionic liquids, although the highest Mw (72 400) was obtained. Spectroscopic studies confirmed that [Rh(OMe)(cod)]2 reacted with MOI · Cl forming new carbene Rh(I) complex, which can participate in the polymerization process. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
10.
11.
Effects on the recycling efficiency of thermoregulated phase-separable Rh/PETPP(P-[p-C6H4O(CH2CH2O)nH]3,N=3n) complex catalyst involved in hydroformylation of 1-decene are for the first time presented.It was found that the loss of Rh is dependent greatly on the composition of phosphine ligand PETPP and the organic solvent employed in the reaction. 相似文献
12.
A copper(I)‐catalyzed tandem reaction of 2‐iodoanilines with isothiocyanates was achieved in hydrophobic [bmim][PF6] ionic liquid under mild conditions, generating a variety of 2‐aminobenzothiazoles in good to excellent yields. The tandem reaction that was carried out in [bmim][PF6] has some obvious advantages such as accelerated reaction rate and increased yield as compared with the reaction run in volatile solvents such as toluene. Furthermore, the CuI/1,10‐phenanthroline catalytic system can be reused up to eight times without loss of activity and efficiency. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
13.
A. A. Kabro S. E. Lyubimov M. G. Maksimova S. K. Moiseev K. N. Gavrilov V. N. Kalinin 《Russian Chemical Bulletin》2007,56(3):540-542
Allylation of dimethyl malonate with 1-(4-chlorophenyl)prop-2-enyl methyl carbonate in the presence of [Pd(All)Cl]2, [Rh(COD)Cl]2, [Ir(COD)Cl]2 (COD is cycloocta-1,5-diene), and a chiral ferrocenyl-containing phosphite ligand based on (R)-BINOL (BINOL is 2,2′-dihydroxy-1,1′-binaphthyl) in CH2Cl2 gave a mixture of linear and branched cross-coupling products, the latter having a moderate optical purity (below 51%). The
rhodium-and iridium-catalyzed reactions were very highly regioselective (regiospecific in the case of Ir), giving a branched
product. In ionic liquids ([bmim][BF4] and [bdmim][BF4]) (bmim is 1-butyl-3-methylimidazolium and bdmim is 1-butyl-2,3-dimethylimidazolium), the Ir-catalyzed reaction regiospecifically
afforded a branched product as a racemate. The same result was obtained with [Ir(COD)Cl]2 as a catalyst; this reaction easily occurred in ionic liquids even without a base.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 519–521, March, 2007. 相似文献
14.
Detlef Selent Anke Spannenberg Christoph Kubis Armin Brner 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(4):398-401
A hydroxy phosphonite was found to be unstable during the catalyst preformation routine applied towards a rhodium olefin hydroformylation catalyst. C—P bond cleavage occurred when the phosphonite was reacted with [(acac)Rh(1,5‐COD)] (acac is acetyl acetate and 1,5‐COD is cycloocta‐1,5‐diene) at 80 °C and 20 bar of CO/H2. As a result, a nearly planar six‐membered ring structure consisting of two rhodium(I) cations and two bridging phosphorous acid diester anions was formed, namely bis[μ‐(4,8‐di‐tert‐butyl‐2,10‐dimethoxydibenzo[d,f][1,3,2]dioxaphosphepin‐6‐yl)oxy]‐1:2κ2P:O;1:2κ2O:P‐bis{[6‐([1,1′‐biphenyl]‐2‐yloxy)‐4,8‐di‐tert‐butyl‐2,10‐dimethoxydibenzo[d,f][1,3,2]dioxaphosphepine‐κP]carbonylrhodium(I)} toluene tetrasolvate, [Rh2(C22H28O5P)2(C34H37O5P)2(CO)2]·4C7H8. Further coordination of phosphite and of carbonyl groups resulted in 16‐electron rhodium centres. 相似文献
15.
The water‐soluble phosphine ligands, 1,3,5‐triaza‐7‐phosphatricyclo[3.3.1.13,7]decane (tpa) and 1‐alkyl‐1‐azonia‐3,5‐diaza‐7‐phosphatricyclo[3.3.1.13,7]decane iodides (Rtpa+I−), with alkyl=methyl(mtpa+I−), ethyl (etpa+I−) and n‐propyl, (ptpa+I−), and mtpa+Cl− react with [Rh2Cl2(CO)4] giving the rhodium(I) complexes [RhCl(CO)(tpa)2], [RhI(CO)(Rtpa+I−)2], [RhCl‐(CO)(mtpa+Cl−)3] and [RhI(CO)(Rtpa+I−)3]. The properties and reactivities of the complexes have been investigated using 1H and 31PNMR and IR spectroscopies. The five‐coordinate complexes in solutions show dynamic properties. The complexes are catalysts of the water‐gas shift reaction, the hydrogenation of CC and CO bonds, the hydroformylation of alkenes and the isomerization of unsaturated compounds. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
16.
17.
Changxi Deng Guangnan Ou Jiarong She Youzhu Yuan 《Journal of molecular catalysis. A, Chemical》2007,270(1-2):76-82
A biphasic catalytic system with water-soluble rhodium complexes of sulfonated (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (labeled as (R)-BINAPS) in ionic liquid BMI·BF4 has been developed for the asymmetric hydroformylation of vinyl acetate under mild conditions. The corresponding ruthenium complexes have been investigated for the biphasic asymmetric hydrogenation of dimethyl itaconate. The biphasic asymmetric hydroformylation of vinyl acetate provided 28.2% conversion and 55.2% enantiomeric excess when BMI·BF4–toluene was used as the reaction medium at 333 K and 1.0 MPa for 24 h. The biphasic asymmetric hydrogenation of dimethyl itaconate in BMI·BF4–iPrOH at 333 K and 2.0 MPa afforded 65% enantiomeric excess with an activity similar to the homogenous analogs. Both biphasic catalytic systems with (R)-BINAPS ligand could be reused several times without significantly decrease in the activity, enantio- and regio-selectivities. The effects of properties of ionic liquid, molar ratio of ligand to rhodium, temperature, pressure and reaction time have been discussed. 相似文献
18.
1‐Dodecene Hydroformylation Catalyzed by Water Soluble Rhodium Phosphine Complex in Two‐Phase System
1‐Dodecene hydroformylation catalyzed by water soluble rhodium complex [RhCl(CO) (TPPTS)2] was studied in the presence of TTPTS [P(m‐C2H4SO3Na)3] and CTAB (cetyltrimethyl ammonium). The influence of reaction parameters was discussed in detail based on micelle effect in biphasic system. The modification for the microcircumstance of micelle interface was conducted by the introduction of a catalyst promoter TPPDS [PhP(m‐C2H4SO3Na)2] into the reaction solution. A synergistic effect between TPPDS and TPPTS on the regioselectivity of 1‐dodecene hydroformylation was observed. The selectivity of linear aldehyde in the products was so high as 95.7% at the molar ratio of [TPPDS]/[TPPTS] = 0.5. 相似文献
19.
The potential energy profile for Rh‐catalyzed asymmetric hydroformylation of vinyl formate is mapped out using a nonlocal density functional method (B3LYP). This study focuses on the enantio‐ and regioselectivity of asymmetric hydroformylation. All the structures are optimized at the B3LYP/6‐31G(d,p) level(LANL2DZ(d) for Rh, P). As illustrated by computation, the olefin insertion step is irreversible because of higher activation free energy of the reverse reaction than that of forward reaction, so it is the determining step for both the regioselectivity and enantioselectivity in asymmetric hydroformylation. The lowest activation free energy in vinyl insertion is the path 2a → TS1a (ΔG≠ = 47.92 kJ/mol), giving rise to the preferred product as (S)‐1‐formylenthyl formate. Throughout the catalytic cycle, the H2 oxidative addition has the highest activation free energy, 77.24 kJ/mol, so it is the rate‐limiting step for the whole catalytic cycle. The calculation results are in agreement with many experiment investigations. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献