Rhodium Catalyzed [2π + 2π + 2π]-Cycloaddition of Alkynyl-Ynamides and Carbon Disulfide to Indolo-Thiopyrane Thiones

The synthesis of new indoloannulated thiopyranethiones is reported. The key-step is a rhodium-catalyzed [2 + 2 + 2]-cycloaddition of alkynyl-ynamides with carbon disulfide to close the pyrrole and the thiopyranethione rings simultaneously. A violet idolothiopyrane thione or a mixture of the violet and a red isomer result from [RhCl(C8H14)2]2/3BINAP catalyzed cycloadditions, the regiochemistry is controlled by the substitution pattern on the alkynyl-ynamide.

Study on the Recovery of Rhodium from Spent Organic Rhodium Catalysts of Acetic Acid Industry Using Pyrometallurgical Process

A new process recycling rhodium from organic waste containing rhodium in acetic acid industry is developed. Use the special affinity of base metal sulfides (FeS, Ni2S3 , CuS, etc.) on platinum group metals, adopting high nickel matte trapping-aluminothermic activation method to recovery rhodium from incinerator residue of organic rhodium waste. The method is shorter process, lower equipment requirement, and the higher activity of rhodium black. In pyrometallurgy enrichment process,the recovery rate of rhodium reached 94.65%, the full flow of rhodium recovery rate was 92.04%.

Rhodium-catalyzed selective[2+2+2]cyclizations of 1,6-diynes with monoynes leading to isoindolines and isobenzofurans

A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yields.The center atoms (N,O) in the diynes showed a significant effect for the cyclization.

Perfection of Perovskite Grain Boundary Passivation by Rhodium Incorporation for Efficient and Stable Solar Cells

Organic cation and halide anion defects are omnipresent in the perovskite films,which will destroy perovskite electronic structure and downgrade the properties of devices.Defect passivation in halide perovskites is crucial to the application of solar cells.Herein,tiny amounts of trivalent rhodium ion incorporation can help the nucleation of perovskite grain and passivate the defects in the grain boundaries,which can improve efficiency and stability of perovskite solar cells.Through first-principle calculations,rhodium ion incorporation into the perovskite structure can induce ordered arrangement and tune bandgap.In experiment,rhodium ion incorporation with perovskite can contribute to preparing larger crystalline and uniform film,reducing trap-state density and enlarging charge carrier lifetime.After optimizing the content of 1% rhodium,the devices achieved an efficiency up to 20.71% without obvious hysteresis,from 19.09% of that pristine perovskite.In addition,the unencapsulated solar cells maintain 92% of its initial efficiency after 500 h in dry air.This work highlights the advantages of trivalent rhodium ion incorporation in the characteristics of perovskite solar cells,which will promote the future industrial application.

Asymmetric Catalytic Hydrogenation Using Rhodium Diphosphinites Derived From D-glucose and D-mannitol

Three diphosphinites were synthesized for preparing rhodium-diphosphinite complexes.The complexes were used for asymmetric catalytic hydrogenation of amino acid precursor α-acetamidocinnamic acid and its methyl ester. With all complexes, D-amino acid is the most abundant product.

Synthesis of palladium-rhodium bimetallic nanoparticles for formic acid dehydrogenation

Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol(PVA) as protecting agent and NaBH4 as reducing agent,using carbon nanofibers with high graphitization degree(HHT) as the desired support.The synthesized catalysts were characterized by means of Transmission Electron Microscopy(TEM) and inductively coupled plasma optical emission spectroscopy(ICP-OES).TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm,with the presence of few large agglomerated nanoparticles.For bimetallic catalysts,EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one(calculated Pd:Rh molar ratio:90-10,69-31,49-51,40-60).The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to H2.It was found that Pd-Rh molar ratio strongly influences the catalytic performance.Pd-rich catalysts were more active than Rh-rich ones,with the highest activity observed for Pd90:Rh10(1792 h^(-1)),whereas Pd69:Rh31(921 h^(-1)) resulted the most stable during recycling tests.Finally,Pd90:Rh10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor,showing good yield to adipic acid.

A New Indicator Reaction and Its Application-Catalytic Determination of Ultratrace Amounts of Rhodium with Linear Sweep Voltammetry

Introduction Sensitive linear sweep voltammetry to have been applied to the catalytic kinetic analysis may be helpful for the application of some organic reagents to the analysis of inorganic ones by voltammetry, The catalytic reaction-linear sweep voltammetric method for the determination of noble metals, such as Ag, Os, Ru and Ir has been developed, but no report about the method for the determination of rhodium has been published so far.

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）12 with 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.

Separation and Determination of Cobalt, Rhodium,Nickel and Iridium with 2-(6-Methyl-2-Benzothiazolylazo)-5-Diethylamino Phenol by HPLC

The synthesis and spectrophotometric properties of 2-(6-methyl-2-benzothiazolylazo)-5-diethylamino phenol (MBTAE), and the use of it as a precolumn derivatizing reagent to separate Co(Ⅱ), Ni(Ⅱ), Rh(Ⅲ) and Ir( Ⅳ) complexes by HPLC are discussed. When the mobile phase consists of methanol/water(90/10 Ⅴ/Ⅴ), acetate buffer with pH 4. 0 and 5×10-5 mol/L EDTA solution, the four complexes Can be separated within 9 min on ODS column. The detection limits (20 μL sample size) are 0. 059 ppb, 0. 062 ppb, 0. 053 ppb and 0. 049 ppb for Co(Ⅱ) , Rh(Ⅲ), Ni(Ⅱ) and lr(Ⅳ) respectively at a signal-to-noise ratio of 3.

SYNTHESIS AND CATALYTIC HYDROSILYLATION PROPERTY OF POLYSILOXANE-SUPPORTED MERCAPTOSELENAETHER PLATINUM OR RHODIUM COMPLEX

Silica-bound mercaptoselenaether-containing silsesquioxane and its plat-inum or rhodium complex were synthesized from γ-(2,3-epithiopropyl) propyltrimethoxysi-lane via ring-opening reaction with bis(2-hydroxyethyl) sclenide, followed by hydrolysisand immobilization on fumed silica, and then reacting with potassium chloroplatinite orrhodium chloride in acetone under nitrogen atmosphere. It was found that two noble metalcomplexes can catalyze the hydrosilylation of olefins with triethoxysilane effectively. Theinfluences of temperature, the amount of complex used, the nature of olefin on catalyticactivity were investigated.

Simultaneous Spectrophotometric Determination of Trace Palladium and Rhodium with2，4－TADAT

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Platinum/rhodium Alloy Bushing for Drawing Glass Fibers in Centrifugal-spinneret-blow Process

In this paper,glass fibers were prepared by centrifugal-spinneret-blow(CSB) process.The molten glass got different flow rate from 390 kg/h to 270 kg/h by adjusting the electric current of platinum/10 rhodium alloy bushing.The diameter and microstructure of glass fibers have been investigated by scanning electron microscopy(SEM) and vertical optical microscope(VOM).The results indicated that the flow rate of molten glass was proportional to the diameter of glass fibers when the molten glass got main flow rate of 330 kg/h.The lower the flow rate was,the finer the average diameter was.

Studies on Dual-beam Spectrometric Simultaneous Determination of Platinum and Rhodium with Water-Insoluble Porphine T(3-M-4HP)P

The optimal conditions for the complexation reaction of meso- tetra(3-methoxy-4-hy-droxyphenyl) porphine T(3-M-4HP)P with platinum and rhodium are presented. Beer’ s Law is obeyed when the concentration of rhodium is in the range of 0. 45-1.15 μg/25mL. The molar absorptivity of rhodium was found to be 1.99×106 L·mol-1·cm-1 at 460 nm. The value of εPt was found to be 6. 28×105 L·mol-1·cm-1 by linear regression method. The K coefficient method and compensating coefficient were used to determine platinum and rhodium simultaneouly without removal or masking of the interferents in the sample. The results for the determination of platinum and rhodium in the mixed solution of platinum and rhodium are satisfactory.

New insight into the adsorption of ruthenium,rhodium,and palladium from nitric acid solution by a silica-polymer adsorbent

A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results revealed that iso Bu-BTP/SiO2-P exhibited unique adsorption properties such as high saturation adsorption capacity(Ru:0.35 mmol g^-1,Rh:0.32 mmol g^-1,Pd:1.05 mmol g^-1)and excellent selectivity over other metal ions,such as lanthanides(SF(PGM/M)>40)in 1 M HNO3 solution.The adsorption process conformed to the pseudosecond-order model and Langmuir model.From the UV,FTIR,and XPS analyses,it can be concluded that the strong affinity between functional groups(C–N=C)and metal ions as well as NO3-played a role in coordination during the adsorption process.Furthermore,the desorption behavior was studied,and it was found that the adsorbed Pd,Rh,and Ru could be eluted with a 0.01 M nitric acid–0.1M thiocarbamide solution,5M hydrochloric acid,and sodium hypochlorite(CP)solution,respectively.Finally,based on those findings,a simple process for the separation and recovery of Pd,Rh,and Ru from high-level liquid waste using iso Bu-BTP/SiO2-P was designed and proposed.

Rhodium-catalyzed asymmetric ring opening of azabenzonorbornadiene with substituted piperazine nucleophiles

We have developed an asymmetric ring opening reaction of azabenzonorbornadiene with substituted piperazine. By increasing the amount of catalyst (from 2.5 to 5%) and ligands (5 to 10%) as well as addition of ammonium iodide, the products can be obtained in high yield and the reaction time shortened dramatically, but the ee values were rather low.

Thermoelectric Properties of Misfit Layered Bismuth-Based Rhodium Oxides, (Bi,Pb)₂Sr₂Rh₂O_y

Rhodium oxides, including a misfitlayered structure with alternate stacking of a rock salttype layer and a hexagonal RhO2 layer, are expected to have good thermoelectric properties. Among them, the thermoelectric properties (electrical conductivity (σ), Seebeck coefficient (S), Figure of merit (ZT) and calculated thermal conductivity (κ) by S, σ, ZT, and absolute temperature (T)) of bismuth-based rhodium oxides ((Bi1-x,Pbx) 2Sr2Rh2Oy, x = 0 and 0.02, hereafter BSR and BPSR, respectively) were investigated. In comparison with Bi2Sr2Co2Oy (BSC) at 700°C, S and κ enhanced (increased S, 110 (BSR) and 105 μV K-1 (BPSR) from 85 μV K-1 (BSC) and decreased κ, 0.32 (BSR) and 0.50 W m-1 K-1 (BPSR) from 1.75 W m-1 K-1 (BSC)), whereas σ decreased (15 (BSR) and 31 S cm-1 (BPSR) from 70 S cm-1 (BSC)). BPSR reached the highest ZT value of 0.067 at 700°C, compared to those of 0.056 (BSR) and 0.027 (BSC).

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.

Spectroscopic Evaluation of the Molecular Structures of di-μ-Chlorobis(1,5-Cyclooctadiene) Iridium (I) and Rhodium (I) Complexes

Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from the single-molecule vapor-phase density functional theory (DFT) calculation that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic analysis study confirms that in the solid phase, the two complexes retain the higher D2h symmetry. The vibrational wavenumbers of certain modes associated to free 1,5-cyc- looctadiene were observed to be shifted to lower values upon coordination with rhodium or iridium metals. It was also found theoretically that the metal-olefin interaction is slightly more pronounced for iridium metal.

Improving the Quality of Thermocouple Wire Made of Platinum-rhodium Alloys

For the manufacture of S-type thermocouple the so-called thermocouple wire of platinum and platinum-rhodium alloy is used.One of the main technical requirements for the quality of the wire,according to State Standard of Russia(GOST 10821),is the uniformity of its largest thermoelectric force(Thermo-emf) in the length different sections.It was found that a determining impact on the uniformity of the wire thermo-emf is the distribution of rhodium along the length of the wire.The impact of platinum-rhodium melt crystallization conditions on the inhomogeneity of wire manufactured from it.It was suggested that the chemical inhomogeneity of the wire is related to the liquation phase of platinum-rhodium alloy.

Rhodium Nanoparticle-Loaded Carbon Black Electrocatalyst for the Glycerol Oxidation Reaction in Alkaline Medium

Rhodium nanoparticle-loaded carbon black (Rh/CB) was prepared by a wet method, and its activity and durability for glycerol oxidation reaction (GOR) in alkaline medium were compared with Pt, Pd and Au nanoparticle-loaded CB (Pt/CB, Pd/CB and Au/CB). In the cyclic voltammogram of the Rh/CB electrode, the redox waves due to hydrogen adsorption/desorption and the surface OH monolayer formation/reduction were observed at more negative potentials than the Pt/CB and Pd/CB electrodes. The onset and peak potentials of the GOR current densities for the Rh/CB electrode were ca. –0.55 and –0.30 V vs. Hg/HgO, respectively, which were 0.10 and 0.20 V more negative than the Pt/CB electrode whose GOR activity was the best, indicating that Rh was a fascinating metal for reducing the overpotential for GOR. In the electrostatic electrolysis with the Rh/CB and Pt/CB electrodes, the decrease in the GOR current density in the former with time was suppressed compared to that in the latter, suggesting that the tolerance to poisoning for the Rh/CB electrode was superior to that for the Pt/CB electrode.