MPa Of CO Research Articles

Microshear Bond Strength of Composite Resin to Enamel Treated With Titanium Tetrafluoride and the Carbon Dioxide Laser (10.6 µm): An In Vitro Study.

Introduction: The present study aims to assess the microshear bond strength (µSBS) of composite to enamel treated with titanium tetrafluoride (TiF4 ) and CO2 laser irradiation. Methods: Fifteen human molars were sectioned and their enamel surfaces were abraded. The sections were randomly assigned to 5 groups (n=15): (CO); control group, (AP); treated with 1.23% acidulated phosphate fluoride (APF) for 4 minutes, (Ti); 4% TiF4 for 1 minute, (L+AP); CO2 laser irradiation (10.6 µm wavelength, 1 W peak power, 10 ms pulse duration, 500 ms repetition time, 0.2 mm beam spot size at the tissue level, 2 cm distance of handpiece tip to tissue surface (DSE, South Cores) followed by 1.23% APF, and (L+ Ti); 10.6μm CO2 laser irradiation followed by 4% TiF4 for one minute. Using Tygon tubes, Z250 (3M/ESPE) composite was bonded to the surface of the samples. The µSBS of composite to enamel was measured using a microtensile testing machine after 500 thermal cycles. The data were analyzed by one-way ANOVA and the Tukey HSD test (P <0.05). Results: The mean µSBS was 20.66, 20.21, 13.44, 23.01, and 10.16 MPa in CO, AP, Ti, L+AP, and L+Ti groups respectively. Significant differences were observed between CO and Ti (P =0.026) and also CO and L+ Ti (P <0.0001). Conclusion: The application of TiF4 per se and after CO2 laser irradiation on enamel decreased the µSBS of composite to enamel; on the other hand, APF alone and after laser irradiation did not have any adverse effect on the µSBS of composite to enamel.

Choline-based eutectic mixtures as catalysts for effective synthesis of cyclic carbonates from epoxides and CO2

• Choline salts have been mixed with hydrogen bond donors to form eutectic mixtures. • Choline-based eutectic mixtures catalyze CO 2 conversion to cyclic carbonates. • Carbonatation run in mild condition of temperature (80 °C) and pressure (0.1–0.4 MPa). • Good to very good yields are obtained on various terminal epoxides. • The eutectic catalysts are bio-based, non-toxic, recyclable and easily synthesized. CO 2 is a renewable, abundant and cheap C1-feedstock and its conversion to cyclic carbonates starting from epoxides has been widely explored in the last years. Nevertheless, conducting this reaction under mild and sustainable conditions is still a challenging task. Herein we present the use of choline-salt based eutectic mixtures as catalysts for the reaction of CO 2 with epoxides to give cyclic carbonates. Choline chloride and choline iodide have been coupled with various hydrogen bond donors (HBDs), mainly cheap and bio-based carboxylic acids and polyols, to form two classes of eutectic mixtures. Very good yields were achieved under mild conditions (80 °C in 7–22 h) for various terminal epoxides, with both classes of catalysts. While a pressure of 0.4 MPa of CO 2 is required to obtain appreciable conversions using choline chloride-based mixture, atmospheric pressure of CO 2 (balloon) has been successfully used with choline iodide-based mixtures. Furthermore, the catalysts could be recycled without appreciable loss of the catalytic activity. The improved catalytic performance of both choline-based eutectic mixtures is attributed to the synergistic activity of the halide, responsible for the opening of the epoxy-ring, and the HBD that has a role in the stabilization of the alkoxide intermediate.

Synthesis of cyclic carbonates by ruthenium(VI) bis-imido porphyrin/TBACl-catalyzed reaction of epoxide with CO2

The catalytic activity of the ruthenium(VI) bis-imido porphyrin complex/TBACl binary system in promoting the CO[Formula: see text] cycloaddition to epoxides forming cyclic carbonates is here reported. The system was very efficient in catalyzing the conversion of differently substituted epoxides under mild experimental conditions (100 [Formula: see text]C and 0.6 MPa of CO[Formula: see text]. Even if the sole TBACl resulted active under the optimized experimental conditions, the addition of ruthenium species was fundamental to maximizing the reaction productivity both in terms of epoxide conversions and cyclic carbonate selectivities. A preliminary mechanistic study indicated a positive role of ruthenium imido nitrogen atom in activating carbon dioxide.

ChemInform Abstract: Synthesis of 2‐Oxazolidinone by N‐Heterocyclic Carbene‐Catalyzed Carboxylative Cyclization of Propargylic Amine with CO2.

Abstract By employing N-heterocyclic carbenes as catalysts, the carboxylative cyclization of propargylic amine proceeded under 0.6 MPa of CO 2 to afford the corresponding 2-oxazolidinone at 90 °C in 2-propanol. Among N-heterocyclic carbenes, 1,3-di- t -butylimidazol-2-ylidene was the most effective catalyst for the reaction, providing 2-oxazolidinone in a maximum chemical yield of 99%.

Mechanistic studies on the selective oxidative carbonylation of MeOH to dimethyl oxalate catalyzed by [Pd(COOMe)n(TsO)2−n(PPh3)2] (n = 0, 1, 2) using p-benzoquinone as a stoichiometric oxidant

The reactivity of the complexes cis-[Pd(OTs)2(PPh3)2] (I), trans-[Pd(COOMe)(OTs)(PPh3)2] (II) and trans-[(COOMe)2(PPh3)2] (III), regarding the catalytic oxidative carbonylation of MeOH to dimethyl oxalate (DMO) using benzoquinone (BQ) as a stoichiometric oxidant, has been studied in CD2Cl2/MeOH (10/1, v/v) by 1H and 31P{1H} NMR spectroscopy. I reacts with CO and MeOH at 193 K giving II, which is transformed into III upon addition of a base. The same occurs in the presence of BQ. Instead, if the base is added before admission of CO, [Pd(BQ)(PPh3)2] is formed. Starting also from II, complex III is formed only after addition of a base. The base neutralizes TsOH which is formed in the transformation of I to II and III. III is unstable in the presence of 1 equivalent of TsOH and it is transformed into II. At 333 K, under 0.4 MPa of CO, III decomposes with formation of DMO and dimethyl carbonate (DMC) (15%) each), whereas, in the presence of BQ, III is unstable already at 298 K, with formation of only DMO (10%). Catalysis to DMO is observed at 333 K. Thus BQ enhances the reactivity of III and directs the catalysis selectively to DMO.I, II and III have also been used in catalytic experiments in pure MeOH at 298 K, under 0.3 MPa of CO. II and III are active even in the absence of a base (TOF ca. 30 h−1). I is active only after addition of a base. A catalytic cycle is proposed.

Efficient [WO4]2–-Catalyzed Chemical Fixation of Carbon Dioxide with 2-Aminobenzonitriles to Quinazoline-2,4(1H,3H)-diones

A simple monomeric tungstate, TBA(2)[WO(4)] (I, TBA = tetra-n-butylammonium), could act as an efficient homogeneous catalyst for chemical fixation of CO(2) with 2-aminobenzonitriles to quinazoline-2,4(1H,3H)-diones. Various kinds of structurally diverse 2-aminobenzonitriles could be converted into the corresponding quinazoline-2,4(1H,3H)-diones in high yields at atmospheric pressure of CO(2). Reactions of inactive 2-amino-4-chlorobenzonitrile and 2-amino-5-nitrobenzonitrile at 2 MPa of CO(2) also selectively proceeded. The present system was applicable to a g-scale reaction of 2-amino-5-fluorobenzonitrile (10 mmol scale) with CO(2) and 1.69 g of analytically pure quinazoline-2,4(1H,3H)-dione could be isolated. In this case, the turnover number reached up to 938 and the value was the highest among those reported for base-mediated systems so far. NMR spectroscopies showed formation of the corresponding carbamic acid through the simultaneous activation of both 2-aminobenzonitirile and CO(2) by I. Kinetic and computational studies revealed that I plays an important role in conversion of the carbamic acid into the product.

CO2 microbubble contrast enhancement in x-ray angiography

To demonstrate that carbon dioxide (CO2) microbubble contrast enhancement depicts blood vessels when used for x-ray examinations. Microbubbles were generated by cavitation of physiological saline to which CO2 gas had been added using an ejector-type microbubble generator. The input pressure values for CO2 gas and physiological saline that produced a large quantity of CO2 microbubbles were obtained in a phantom. In an animal study, angiography was performed in three swine using three types of contrast: CO2 microbubbles, conventional CO2 gas, and iodinated contrast medium. For CO2 microbubble contrast enhancement, physiological saline, and CO2 gas were supplied at the input pressures calculated in the phantom experiment. Regions of interest were set in the abdominal aorta, external iliac arteries, and background. The difference in digital values between each artery and the background was calculated. The input pressures obtained in the phantom experiment were 0.16MPa for physiological saline and 0.5MPa for CO2 gas, with physiological saline input volume being 8.1ml/s. Three interventional radiologists all evaluated the depictions of all arteries as "present" in the CO2 microbubble contrast enhancement, conventional CO2 contrast enhancement, and iodinated contrast enhancement performed in three swine. Digital values for all vessels with microbubble CO2 contrast enhancement were higher than background values. In x-ray angiography, blood vessels can be depicted by CO2 microbubble contrast enhancement, in which a large quantity of CO2 microbubbles is generated within blood vessels.

Hear Bond Strength of Three Porcelain Repair Systems on Porcelain in Dry and Aged Conditions

Objective: This study compared the durability of bond strength of a resin composite to feldspathic ceramic by using three porcelain repair systems. Methods: Sixty ceramic blocks (Vitablocks Mark II) were divided into three groups, according to the repair method (CO [Cojet repair kit], CL [Clearfil repair kit], and UL [Ultradent repair kit]). Composite resin was photo-polymerized on each ceramic. Half of the specimens were submitted to the shear bond strength test after 24 hours of water storage or thermal cycling. The bond strength data was analyzed by Weibull analysis and Wald tests (p=0.05). Results: The characteristic bond strength values (σ0 ) of repair systems in dry conditions were 5.823, 6.512 and 6,867 MPa and after aging conditions these were 4.112, 3.935 and 4.210 MPa for CO, CL and UL, respectively. Wald test results revealed that there were significant differences among groups in characteristic bond strength (σ0 ) (p<0.001). Conclusion: Thermal cycling had a significant effect on the bond strength of three repair kits and bond strength results decreased after thermal cycling.

Hydrogenation of aniline to cyclohexylamine in supercritical carbon dioxide: Significance of phase behaviour

Hydrogenation of aniline to cyclohexylamine was carried out in supercritical carbon dioxide using a variety of noble metal (Pt, Pd and Rh) catalysts. At 80 °C and 8 MPa of CO 2 pressure, >95% of aniline conversion with 93% selectivity to cyclohexylamine was achieved on 5% Rh/Al 2O 3. A strong influence of phase behaviour related to the CO 2 pressure was found on the conversion and selectivity. Optimization of reaction parameters resulted in a higher overall activity in the biphase (liquid substrate + gaseous H 2 and CO 2) than in the single phase (liquid substrate–CO 2–H 2) condition. It has been found that the interaction of CO 2 with amine leads to the formation of solid carbamic acid, which enhanced the selectivity of cyclohexylamine, but reduced the conversion significantly. Furthermore, reaction temperature played a crucial role in preventing the formation of carbamic acid and also maintained a reasonably high reaction performance in terms of conversion and selectivity.

Experimental evaluation and performance enhancement prediction of desiccant assisted separate sensible and latent cooling air-conditioning system

CO 2 and R410A desiccant wheel (DW)-assisted separate sensible and latent cooling (SSLC) air-conditioning systems were tested under the AHRI standard. At a 50 °C regeneration temperature, the coefficient of performance (COP) of the vapor compression cycles improved only 7% from the respective baseline systems for both refrigerants. This paper proposed the idea of applying divided condensers (or gas coolers) to the R410A (or CO 2) SSLC system to enhance its performance. It was found that the application of divided heat exchangers to the SSLC system provided sufficiently hot airflow for regenerating the desiccant wheel at both a reduced high side pressure (from 10.4 MPa to 9.7 MPa for CO 2, from 3.46 MPa to 3.45 MPa for R410A) and a reduced discharge temperature from the condenser (gas cooler) (4 K lower for both refrigerants). The COP improvement is 36% and 61% to R410A and CO 2 baseline systems, respectively.

Catalytic hydrogenation rate of polycyclic aromatic hydrocarbons in supercritical carbon dioxide containing polymer-stabilized palladium nanoparticles

Catalytic hydrogenation of polycyclic aromatic hydrocarbons (PAHs) with up to four fused benzene rings over high-density-polyethylene-stabilized palladium nanoparticles in supercritical carbon dioxide via in situ UV/Vis spectroscopy is presented. PAHs can be efficiently converted to saturated polycyclic hydrocarbons using this green technique under mild conditions at 20 MPa of CO 2 containing 1 MPa of H 2 at 40–50 °C. Kinetic studies based on in situ UV/Vis spectra of the CO 2 phase reveal that the initial hydrogenation of a given PAH and the subsequent hydrogenations of its intermediates are pseudo-first-order. The hydrogenation rate of the latter is always much smaller than that of the former probably due to increasing steric hindrance introduced by the hydrogenated benzene rings of PAHs which impedes the adsorption process and hydrogen access to PAHs on catalyst surfaces.

Crystal Transformation and Host Molecular Motions in CO2Adsorption Process of a Metal Benzoate Pyrazine (MII= Rh, Cu)

For the purpose of investigating the correlation between host gas adsorption ability and structural flexibility, the combination of metal benzoate complexes [M(II)(2)(bza)(4)] (M(II) = Rh (a), Cu (b); bza = benzoate) and pyrazine derivatives (pyz = pyrazine (1), 2-mpyz = 2-methylpyrazine (2), 2,3-dmpyz = 2,3-dimethylpyrazine (3)) yields a series of one-dimensionally assembled complexes. The study of the adsorption properties of this series was examined for CO(2), H(2), N(2), O(2), and Ar gases at 195 K (CO(2)) or at 77 K (all others). The adsorption manners of these complexes are similar for each gas, while the pressure at which adsorption started or rapidly grew increased with a rise in the number of methyl groups in the case of adsorbable gases. The maximum amount of adsorption was a positive integer, e.g., 3 molecules per M(2) unit for 1 and 2 and 2 molecules per M(2) unit for 3 in the case of CO(2) adsorption for all complexes at 0.1 MPa of adsorbable gases. Structural transformation was observed accompanying gas adsorption. This transformation was observed when the adsorption amount reached 1 molecule per M(2) unit, suggesting a correlation of the adsorption amount and dynamic adsorption behavior. Single-crystal X-ray analyses of nonincluded crystals and CO(2) inclusions for all hosts (1-3) revealed that large structural changes occurred through CO(2) adsorption to increase the inner space for adsorption gases, depending on the substituents on the pyrazine ring. These facts were confirmed as a transition by DSC measurements using a mixed CO(2)/N(2) gas atmosphere. Solid-state (1)H and (2)H NMR studies of the crystalline sample of 1a and its partially deuterated samples of 1a' (deuterated phenyl group) and 1a'' (deuterated pyrazine) revealed rapid 180 degree-flip motions of the aromatic rings of the host skeletons, which form the walls of the channels. These "rotating" motions would help the diffusion of CO(2) molecules through a narrow channel at relatively low pressure. Indeed, the motions of phenyl groups and methyl-substituted pyrazine moieties of phenyl deuterated 3a were confirmed to be very slow by solid-state (1)H and (2)H NMR spectra, where the amount of adsorbed gas molecules was small for 3a at 0.1 MPa of CO(2).

Gelation, crystallization and morphological transformations of syndiotactic polystyrene in acetophenone and acetophenone + carbon dioxide mixtures at high pressures

The gelation and crystallization processes in 5 wt% solutions of syndiotactic polystyrene in acetophenone and acetophenone + carbon dioxide fluid mixtures were studied in a variable-volume view-cell system over a pressure range from 7 to 50 MPa for CO 2 concentrations up to 40 wt%. The solution in pure acetophenone displayed only a sol–gel (gelation) phase boundary. Solutions containing 25 wt% CO 2 displayed both a sol–gel and a liquid–liquid phase boundary. Solutions containing 40% CO 2 displayed instead a fluid–solid (crystallization) and a liquid–liquid phase boundary. The consequences of crossing the gelation, crystallization or the liquid–liquid demixing boundaries first on the eventual morphology and the crystal structures that develop were investigated. It is shown that when the gelation boundary is crossed first, the resulting crystal structure is the δ form. When the L–L phase boundary is crossed first, polymer-rich phase leads to a mixture of δ + β crystal forms while only the δ form is found in the polymer-lean phase from solutions with 25 wt% CO 2. Crossing the crystallization boundary first in solutions with 40 wt% CO 2, leads to the β form with no presence of the δ crystal form. However, when the liquid–liquid phase boundary is crossed first, the polymer-rich phase forms only the β crystal form and the polymer-lean phase leads to a mixed crystal structure containing the β and δ forms. Formation of the different crystal structures are verified by XRD, FTIR and SEM characterizations and are rationalized with a phase diagram describing the paths the system follows as a result of a change in pressure and/or the temperature.

Hydrogen-adsorption Properties of a Novel Lantern-type Dinuclear Co(BDC)(DABCO)1⁄2

Abstract A three-dimensional (3-D) cobalt coordination polymer Co(BDC)(DABCO)1⁄2 (BDC = 1,4-benzenedicarboxylate; DABCO = 1,4-diazabicyclo[2.2.2]octane), which has a novel lantern-type structure, was synthesized and characterized by X-ray powder diffraction patterns and elemental analysis. In addition, hydrogen-adsorption characteristics were evaluated at 77 K. The highest measured hydrogen uptake was 2.28 wt % at 77 K and 0.1 MPa for Co(BDC)(DABCO)1⁄2.

Studies on the copolymerization of norbornene with CO catalyzed by a new catalytic system PdCl2/phen/M(CF3SO3)n

A new three-component catalytic system, PdCl2/phen/M(CF3SO3)n where M = La, Y, Yb, Zn, and Cu, was studied for the copolymerization of norbornene (NBE) with CO to prepare polyketone (PK). It was found that the CF3SO3H catalytic system gave a low catalytic activity for the copolymerization of norbornene with CO, but when M(CF3SO3)n was introduced instead of CF3SO3H, the PdCl2/phen/M(CF3SO3)n catalytic system exhibited much higher activity. The effects of ligands, M(CF3SO3)n, solvents, and temperatures on the copolymerization have been discussed in detail. The results showed that with 1,10-phenanthroline (phen) and Cu(CF3SO3)2 used as cocatalysts, the corresponding reaction rate reached 82 000 g PK (mol Pd)−1h−1 when the reaction was carried out in methanol at 90°C and 3.0 MPa of CO, and the weight average molecular weight (M w) of the resultant copolymer is 1090 g/mol. The copolymer was characterized with various techniques such as FT-IR, 1HNMR, 13CNMR, TGA, and DSC. The infrared spectrum of the product includes two features at 1697 and 1732 cm−1 for the NBE/CO copolymer in CH3OH that are attributed to carbonyl groups in ketones (repeating unit) and esters (end group), respectively. Due to the tension of the ring of norbornene, the degree of copolymerization is not high.

Interfacially formed poly( N, N-dimethylaminoethyl methacrylate)/polysulfone composite membranes for CO 2/N 2 separation

Interfacially formed poly( N, N-dimethylaminoethyl methacrylate)/polysulfone (PDMAEMA/PSF) composite membranes were developed for CO 2/N 2 separation. A layer of PDMAEMA was deposited on a microporous PSF substrate by the solution coating technique, followed by crosslinking with p-xylylene dichloride (XDC) at the interface between the PDMAEMA solid layer and the crosslinking solution. The hydrophilicity and surface free energy of the membranes were analyzed by contact angle measurements with different probe liquids. The permselectivity of the membrane was shown to be affected by the PDMAEMA deposition time, interfacial crosslinking reaction time, and the PDMAEMA and XDC concentrations in the polymer coating solution and the crosslinking solution, respectively. The composite membrane showed a CO 2 permeance of 85 GPU and a CO 2/N 2 ideal separation factor of 50 at 23 °C and 0.41 MPa of CO 2 feed pressure.

Direct carboxylation of alcohols to organic carbonates: Comparison of the Group 5 element alkoxides catalytic activity: An insight into the reaction mechanism and its key steps

The reaction of carboxylation of alcohols is a sustainable technology for the synthesis of dialkylcarbonates that avoids the use of phosgene. In this paper we describe the behaviour of metal alkoxides of Group 5 elements as homogeneous catalysts in the above reaction, and the isolation and characterization of the active species, i.e. the hemicarbonates formed upon insertion of carbon dioxide into the M–OR bond. Ta and V alkoxo complexes are comparatively discussed with respect to the Nb-analogues, whose synthesis and catalytic properties have been published [M. Aresta, A. Dibenedetto, C. Pastore, Inorg. Chem. 42 (10) (2003) 3256, and references therein]. In this paper, we report for the first time the evidence of insertion of carbon dioxide in tantalum alkoxides [Ta(OR) 5] 2 [R = methyl (Me), ethyl (Et)]. The relevant hemicarbonates Ta(OR) 4[OC(O)OR] have been characterized using spectroscopic techniques (IR and NMR). Tantalum alkoxides and the vanadium compound VO(OR) 3 are shown to be able to catalyze the carboxylation of alcohols at 413 K and 5.5 MPa of CO 2. The trend of reactivity for the Group 5 alkoxides as catalysts for the carboxylation of alcohols is Nb ≫ Ta > V.

Fe- and Co-based bulk glassy alloys with ultrahigh strength of over 4000 MPa

Since the first synthesis of Fe-based bulk glassy alloys in Fe–(Al,Ga)–(P,C,B,Si) system in 1995, a number of Fe- and Co-based bulk glassy alloys have been developed up to date because their alloys are expected to exhibit high mechanical strength and good soft magnetic properties. The maximum diameter of Fe- and Co-based bulk glassy alloys exhibiting high fracture strength of over 4000 MPa is 5 mm for Fe–Co–B–Si–Nb system and 3 mm for Co–Fe–Ta–B–Mo–Si system. The addition of a small amount of Nb or Ta is essential for the increase in their glass-forming ability through the formation of network-like atomic configurations. The primary crystalline phase from supercooled liquid is a metastable complex FCC Fe 23B 6 or Co 23B 6 phase and hence the change to the local atomic configurations leading to the precipitation of the metastable Fe 23B 6 or Co 23B 6-type phase is thought to play an important role in the achievement of high glass-forming ability. The highest fracture strength reached as high as 4250 MPa for Fe–Co–B–Si–Nb alloy and 5545 MPa for Co–Fe–Ta–B–Mo alloy. The fracture strength has a good linear relation with Young's modulus, glass transition temperature or liquidus temperature. It is, therefore, concluded that the origin for the ultrahigh strength is attributed to the strong bonding nature among the constituent elements. Considering that Fe–Si–B amorphous alloy wires developed for several years between 1979 and 1983 have been used as high strength materials for the last two decades, the newly developed high-strength Fe- and Co-based bulk glassy alloys are expected to be used as a new type of ultrahigh strength material by utilizing the advantage points of much higher strength and three-dimensional material form.

A new catalytic system for the copolymerization of dicyclopentadiene with CO: PdCl 2/phen/M(CF 3SO 3) n

A new three-component catalytic system, PdCl 2/phen/M(CF 3SO 3) n , was studied in the copolymerization of dicyclopentadiene (DCPD) with CO. It was found that the PdCl 2/phen/CF 3SO 3H catalytic system gave a very low catalytic activity, and the PdCl 2/phen/M(CF 3SO 3) n catalytic system exhibited high activity when M(CF 3SO 3) n was introduced instead of CF 3SO 3H. The resultant cooligomer was analyzed using various techniques such as FT-IR, 1H NMR, 13C NMR, DSC and TGA. The results indicated that the copolymer was a polyspiroketal (PS) of CO and DCPD. Due to the tension of the ring of DCPD, the degree of copolymerization is low and the degree of crystallinity is also not high. The effects of ligands, M(CF 3SO 3) n , solvents, 1,4-benzoquinone/PdCl 2 molar ratio, and temperatures on the copolymerization have been discussed in detail. The results showed that this novel catalytic system exhibited highly efficient activity, especially when 1,10-phenanthroline (phen) was used as ligand and Cu(CF 3SO 3) 2 was used as cocatalyst. The corresponding reaction rate was 49 000 g PS/molPd h when the reaction was carried out at 60 °C and 3.0 MPa of CO. The weight average molecular weight ( M w) and the number average molecular weight ( M n) of the resultant cooligomer were 1180 g/mol and 564 g/mol, respectively.

A new catalytic system for copolymerization of styrene with CO:PdCl 2/bipy/M(CF 3SO 3) n

A new three-component catalytic system, PdCl 2/bipy/M(CF 3SO 3) n , was studied for copolymerization of styrene with CO to prepare alternating polyketone (PK). It is found that the PdCl 2/bipy/CF 3SO 3H catalytic system had a very low catalytic activity for copolymerization of CO with styrene, but when M(CF 3SO 3) n was introduced instead of CF 3SO 3H, the PdCl 2/bipy/M(CF 3SO 3) n catalytic system exhibited high activity. The copolymer was characterized by elemental analysis, FTIR, 1H NMR, DSC and TGA. The results indicated that the copolymer is a linear alternating copolymer of carbon monoxide and styrene with glass transition temperature, melting point, and decomposition temperature of 275, 350, and 400 °C, respectively. The effects of M(CF 3SO 3) n , ligands, p-benzoquinone/PdCl 2 ratio, solvents, and reaction temperatures on the reaction have been discussed in detail. The results showed that this novel catalytic system exhibited high activity, especially when Cu(CF 3SO 3) 2 was used. The corresponding productivity was 20,000 gPK/molPd h when the reaction was carried out at 338 K for 4 h under 3.0 MPa of CO.