Phosphite Ligand Modified Supported Rhodium Catalyst for Hydroformylation of Internal Olefins to Linear Aldehydes

A phosphite ligand modified heterogeneous catalyst was developed for the hydroformylation of internal olefins to linear aldehydes, which showed a high activity and high regioselectivity and could be separated easily by filtration after reaction in an autoclave. Three nanoporous silica sieves were used to investigate the influence of pore structure and shape selective performance of support on the regioselectivity to the linear products.

A novel thermoregulated phosphine ligand used for the Rh-catalyzed hydroformylation of mixed C_(11-12) olefins in aqueous/organic biphasic system

A novel thermoregulated phosphine ligand PhP(CHCHO)CH(n=22) was synthesized and used for the Rh-catalyzed hydroformylation of mixed Colefins in aqueous/organic biphasic system.Under the optimized conditions,pressure =5 MPa (H:CO=1:1),phosphine/Rh =13(molar ratio),reaction time =6 h and temperature =130℃,the conversion of Colefins and the yield of aldehyde are 99%and 94%,respectively.The catalyst retained in aqueous phase can be easily separated from the product-containing organic phase by simple phase separation and the catalytic activity remains almost constant after four consecutive cycles.

A novel phosphate ligand used for the Rh-catalyzed hydroformylation of cyclohexene in a thermoregulated PEG biphase system

A novel phosphate ligand, tri-（methoxyl polyethylene glycol）-phosphate （TMPGPA）, has been synthesized and used in the Rhcatalyzed hydroformylation of cyclohexene in a thermoregulated PEG biphase system. Under the optimized conditions, pressure = 5 MPa （H2：CO = 1：1）, P/Rh = 10 （molar ratio）, reaction time = 4 h and temperature = 120 ℃, the conversion of cyclohexene and the yield of aldehyde are 99%. The catalyst retained in PEG phase can be easily separated from the organic phase containing product by simple phase separation and reused ten times without obvious loss in activity.

Direct Immobilization of Phosphine-Rhodium Complex on MCM-41 for Propene Hydroformylation

MCM 41 molecular sieve supported Rh PPh 3 catalysts were prepared by the in situ assembling of the metal complex from smaller moieties of Rh(acac)(CO) 2 and ligand of PPh 3. The resulted guest/host materials(Rh PPh 3/MCM 41) were characterized by X ray powder diffraction, FTIR and 31 P( 1H) NMR, and served as catalysts for propene hydroformylation. The results showed negligible change in MCM 41 framework after propene hydroformylation at 393 K. Higher hydroformylation activities were obtained on Rh PPh 3/MCM 41 catalysts compared to that on Rh PPh 3/SiO 2.

CATALYTIC BEHAVIOR OF SILICA-SUPPORTED POLY-γ- AMINOPROPYL- SILOXANE-Co-Ru BIMETALLIC COMPLEX FOR THE HYDROFORMYLATION OF CYCLOHEXENE

The cobalt and ruthenium bimetallic complex of poly-γ-amino-propylsiloxane( abbr. as Si-CH_2-Co-Ru) was prepared, and it was found that it can catalyze the hydroformylation of cyclobexene effectively with the conversion amounting to over 90%. Cyclohexanecarboxaldehyde was first formed in the hydroformylation, and then further hydrogenated to form cylcohexanemethanol. The coversion was affected obviously by the Co/Ru ratio.When Co/Ru molar ratio was 100-150, i.e. in the very low content of noble metal Ru, the catalytic activity of Si-NH_2 -Co-Ru was also very high. The product composition was affected by CO/H_2 ratio in the reaction gas. Aldehyde can be got high selectively by controlling CO/H_2 ratio. Compared with other catalyst system, the Si-NH_2-Co-Ru catalyst has higher catalytic activity and efficiency with very low Ru/Co ratio. The total turnover number was more than 28,800 (based on the amount of ruthenium used).

Hydroformylation of formaldehyde to glycolaldehyde:An alternative synthetic route for ethylene glycol

Hydroformylation of formaldehyde to glycolaldehyde(GA),as a vital reaction in both direct and indirect process of syngas to ethylene glycol(EG),shows great advantages in the aspects of the process complexity and clean production.The hydroformylation of formaldehyde to GA is thermodynamically unfavourable,requiring the development of highly efficient hydroformylation catalytic systems,appropriate reaction conditions and in-depth understanding of the reaction mechanisms.In this review,we have made a detailed summary on the reaction in terms of the reaction network,thermodynamics,metal complex catalysts(including central metals and ligands),reaction conditions(e.g.,temperature,pressure,formaldehyde source and solvent)and promoters.Furthermore,the reaction mechanisms,involving neutral and anionic complex in the catalytic cycle,have been summarized and followed by a discussion on the impact of the crucial intermediates on the reaction pathways and product distribution.A brief overview of product separation and catalyst recovery has been presented in the final part.This review gives new insights into the factors that impact on the formaldehyde hydroformylation and reaction mechanisms,which helps to design more efficient catalytic systems and reaction processes for EG production via the hydroformylation route.

Aqueous Biphasic Hydroformylation of Oleyl Alcohol Catalyzed by Thermoregulated Rhodium Complex

The aqueous biphasic hydroformylation of oleyl alcohol was achieved under thermo-regulated phase transfer catalysis (TRPTC) conditions with Rh(acac)(CO)2 Ph2P[p-C6H4 (OCH2CH2)25OH] (PETPP) complex catalyst formed in situ. The aldehyde yield reached 81.2% within 6 hrs under 140℃ and 5.0 MPa (CO/H2,1/1) and the separated catalysts dissolved in the aqueous phase could be reused for 3 times without evident changes in activity.

RATE－DETERMINING STEP IN OLEFIN HYDROFORMYLATION OVER SUPPORTED AQUEOUS－PHASE CATALYSTS

A series of olefin hydroformylations over supported aqueous-phase rhodium catalyst with the substitUtion of CO/D2 for CO/H2 were cAned out to study the isotope effects of deuterium. The rate of aldehyde formation in CO/D2 was about 1.3 times faster than that in COns2, indicating that the aldehyde formation shows noticeable inverse deuterium isotope effect over SAP catalyst. The results of in-situIR stUdy of ethylene hydroformylation suggest that the reaction rate of acylhydrogenolysis forming aldehyde is the slowest one. It may be inferred from these results that the rate-determining step involved\in aldehyde formation is very probably astep ofhydrogenation.

STUDY ON POLYMER—Ru-Co—BIMETALLIC COMPLEXES CATALYSTS Ⅰ. SYNTHESIS OF CATALYSTS AND THEIR USE FOR THE HYDROFORMYLATION

Six kinds of polymer ligands, supported on SiO_2, containing coordinating atoms P, S and N respectively, have been synthesized. The Ru(Ⅲ)-Co(Ⅱ) bimetallic complexes of these polymer ligands have been obtained and examined as catalysts for the hydroformylation of cyclohexene. The effects of reaction temperature, pressure and Co/Ru ratio etc. on the activities of catalysts were investigated in detail. The catalysts are all polymer-noncarbonyl-metal complexes, easily to be prepared, active and stable. From the experimental results it can be suggested that under reaction conditions such polymer-noncarbonyl-metal complexes convert 'in situ' to polymer-carbonyl-metal complexes, thus become active catalysts. The course of this conversion is supposed as a preliminary approach.

Hydroformylation of Oleyl Alcohol Catalyzed by Rh-OPGPP Complex

Polyether-tailored phosphite modified rhodium complex formed in situ was highly active in the hydroformylation of oleyl alcohol in nonaqueous phosphite/heptane system where the phosphite acted both as the ligand and the second phase. This catalyst was easily separated by simple decantation and can be used for five times with only a slight decrease in activity.

HYDROFORMYLATION OF MMA CATALYZED BY SILICA-SUPPORTED POLY-γ-AMINO PROPYLSILOXANE-Rh-Co BIMETALLIC COMPLEX

A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed that the catalyst could catalyze the reaction in95.6% conversion with 92.8% selectivity for the normal aldehyde, methyl β-formylisobu-tyrate. Such catalyst also showed high stability during the reaction and could be used repeat-edly.

HYDROFORMYLATION CATALYSIS USING POLYMER-SUPPORTED MULTINUCLEAR RHODIUM CARBONYL CLUSTER CATALYSTS

A series of polymer-supported tetranuclear rhodium carbonyl cluster catalysts were prepared b the reaction of Rh4（CO）12with several kinds of polymer supports such as crosslinked poly （N-vinylpyrrolidone） （PNVP） and crosslinked poly （ styrene-co-maleic anhydride） （PMAn）, and subsequently were used to catalyze the hydroformylation of olefins. The catalysts were characterized by IR, SEM and XPS. The influence of the supports structure and crosslinking, metal’s content and particle size of the supports on the catalysts hydroformylation properties was studied. The factors which affect the catalytic conversion were also examined. The experimental results show that the polymer-supported Rh cluster catalysts possess very high catalytic activity and aldehyde selectivity as well as good reproducibility.

DISPERSION EFFECTS OF CLUSTER-DERIVED Rh ON SiO_2 OH ETHYLENE HYDROFORMYLATION

Over Rh_4(CO)_(?z)-derived Rh/SiO_2 catalyst,atmospheric hydroformylation and hydro- genation of ethylene are suggested to be structure sensitive and structure insensitive,res- pectively.

Synthesis of Polymer-Supported Heteronuclear Rhodium- Cobalt Bimetallic Carbonyl Cluster Catalysts and Their Hydroformylation Properties

Tetranuclear Rh-Co bimetallic cluster was synthesized and characterized by IR and XPS. The properties of the anchored catalysts, its stability and the ligand effect were also studied. The experimental results show that the optimal conditions for the hydroformylation of hexene-1 are as follows: the temperature is 80℃, reaction time 8 h, pressure 5. 88×105 Pa, and molar ratio of H2/CO 1. 2/1. 0. Functional groups attached to the donor atom(N) possess more or less some influence on the catalytic behavior. Compared with the homogeneous cluster, the polymer-supported bimetallic cluster is more stable. After the catalytic reaction, the structure of the anchored catalysts was not destroyed. X-ray photoelectron spectroscopy characterization indicates that there is a weak interaction between the polymer support and the active metals.

Insight into the Detailed Mechanism of HRh(CO)(PPh_3)_3 Catalyzed Hydroformylation of 1-Phenyl-1-(3-pyridyl)ethene:A DFT Study

Density functional calculations have been used to study the mechanism of 1-phenyl-1-（3-pyridyl）ethene hydroformylation using rhodium catalyst.Our calculations reveal that the rate-determining step is the oxidative addition of hydrogen molecule and the preferred path is the one involving ts3ans for the lowest activation free-energy （ΔrGa）,63.8 kJ/mol.This reaction is demonstrated to be strong exothermic by-96.6 kJ/mol of branched products and-98.2 kJ/mol of linear products.And the predominant product is the linear 3-phenyl-3-（3-pyridal）propanal （pr-ns） determined by both thermodynamics and kinetics.These results are in agreement with the practicality experimental studies.

CATALYTIC PERFORMANCE OF ETHYLENE HYDROFORMYLATION OVER[H_XRu_3(CO)_9(CCO)]^(2-X)/SiO_2-Al_2O_3,SiO_2 AND MgO(X=0-2)CATALYSTS

The various surface species[H_XRu_3(CO)_9(CCO)]^(2-X)(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and ethane in ethylene hydroformylation.

Water/Oil Diphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO_2 Catalyst

A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.

AN EFFECTIVE ORGANO-BIMETALLIC Rh-Co CLUSTER CATALYST FOR HYDROFORMYLATION

s: RhCo3(CO) 12/Sio2 aller decarbonylated is regenerable under CO, and catalyzes ethylene hydrofornlylation with high activity and stability.

SULFONATED POLYPHENYLENE-SULFIDE AS LI GANDS IN RH-COMPLEXES CATALYZED HYDROFORMYLATION

Sulfonated polyphenylene-sulfide(SPPS)was used as ligands in place of phosphine in Rh-complexes to yield a water-soluble catalyst for hydroformylation of higher olefins in two phasic system.The decreasing catalytic activities and increasing n/b ratios(normal to branch aldehyde ratios)have been found respectively with increasing molar ratios of SPPS to rhodium,and with lowering of reaction temperature,indicating more or less coordinations between thioether sulfides and Rh species in SPPS-Rh compounds,The coordinations were also evidenced by a weak Reman hand observation of the SPPS-Rh compounds at 264 cm^(-1).

Safe Hydroformylation of Aliphatic Alkene in a Flow Reactor

Despite hydroformylation being a very efficient method for the transformation of alkenes, it is not commonly employed in laboratories owing to the flammable/toxic nature of hydrogen and carbon monoxide gases and the necessity of high-pressure equipment in a batch system. Flow chemistry often raises the safety profiles against high-pressure and toxic gases because the diameter of the flow reactor is small. Herein, we show that aliphatic alkenes can be safely hydroformylated in a flow reactor. In our flow method, although the target hydroformylated product was obtained in a low yield (19%), toxic gases were safely treated using a flow reactor. Better yields could possibly be achieved by recycling of the unreacted alkene.