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8-Hydroxyquinoline with Ni(OAc) 2 ·4H 2 O form stable chelate ring structure has good catalytic performance for catalyzing acetylene carbonylation to acrylic acid. [Display omitted] • It was the first time to report the Ni(OAc) 2 ·4H 2 O-8-hydroxyquinoline with high activity for carbonylation of acetylene to acrylic acid. • The catalytic system has no copper, no halogen, no need for acidic protons and no carbon deposition occurring during the reaction process. • The nitrogen-oxygen bidentate ligand with nickel form a ring structure has good catalytic performance in the reaction. • The reaction mechanism catalyzed by Ni(OAc) 2 ·4H 2 O-8-hydroxyquinoline was deduced. A nickel-base nitrogen-oxygen bidentate ligand catalyst was prepared in-situ via the complexation method. Our results show that the ligand with nickel can form a chelate catalyst possessing a ring structure, which exhibits good catalytic performance in the carbonylation reaction of acetylene to acrylic acid (AA). Furthermore, we discovered that, under our optimized conditions, when 8-hydroxyquinoline (HQ) is used as the ligand [c(Ni(OAc) 2 ·4H 2 O) = 15 × 10−6 mol L−1, n(HQ):n(Ni(OAc) 2 ·4H 2 O) = 1:1, V(H 2 O) = 7 mL], 70.1% conversion of acetylene and 92.4% the selectivity of AA is achieved at 200 °C with 8.0 MPa pressure for 30 min. Compared to traditional acetylene carbonylation catalysts and nickel-base phosphine ligand homogeneous complex catalysts, our catalytic system has unique advantages, including no copper, no halogen and no carbon deposition generated during the reaction process. It displays high selectivity and no corrosion of equipment, suggesting that this catalytic system possesses future industrial applications. [ABSTRACT FROM AUTHOR]

Aliphatic-aromatic poly(carbonate- co -ester) random copolymers poly(butylene carbonate- co -furandicarboxylate)s (PBCFs) with different composition had been prepared from dimethyl carbonate (DMC), 1,4-butanediol (BD) and bio-based dimethyl furan-2,5-dicarboxylate (DMFA) by two-step melt polycondensation method. A series of characterization results can be explained as follows: the varying melting temperature ( T m ) and enthalpy ( ΔH m ) displayed that the copolymers were strongly dependent upon the compositions of butylene carbonate (BC) and butylene furandicarboxylate (BF) units. In addition, glass transition temperature ( T g ) noticeably increased with the content of BF units increasing, which agreed with Fox equation; a comparative kinetics research of isothermal crystallization of homopolymer and copolymers with different composition displayed that the existence of BF units could accelerate the crystallization rate of PBC. Furthermore, all of PBCFs exhibited a typical isodimorphic cocrystallization behavior, whose crystal lattice structure shifted from PBC type crystal to PBF type; the thermal stability of PBCFs also expressed to be enhanced during the process of the increasing BF unit content; last but not the least, the mechanical performances could be easily by adjusting the feed components. [ABSTRACT FROM AUTHOR]

Aiming to improve thermal stability of poly(butylene carbonate) (PBC), a series of poly(butylene-co-1,4-cyclohexanedimethylene carbonate) (PBCCs) random copolycarbonates with weight-average molecular weights ( M w ) ranging from 1,09,000 to 1,74,000 g mol −1 and yield of 82.4to 88.4% were synthesized from Diphenyl carbonate (DPC), 1,4-butanediol (BD) and trans-1,4-cyclohexanedimethanol (CHDM) by a two-step melt polycondensation method. The structures and properties were characterized by 1 H NMR, 13 C NMR, FT-IR, GPC, WAXD, DSC, TGA, mechanical testing as well as enzymatic degradation. The results manifested that the triad components were existed in the copolymers with a random sequential structure, and incorporation of cyclohexanedimethylene carbonate (CC) units into PBC could prominently impact the thermal transition behavior, crystallinity as well as thermal stability of PBCCs in a degree. In addition, T g of PBCCs monotonously increased with the increasing CHDM content. WAXD results indicated that the CHDM introduction could obviously change the crystal structure and crystallinity of the copolymers. The thermal stability of PBCCs also expressed to be enhanced during the process of increasing CC unit content. Furthermore, the mechanical properties and biodegradability of copolymers can be easily adjusted by regulating the feed composition. [ABSTRACT FROM AUTHOR]

Various solid bases were synthesized and used as catalyst for direct transesterification of diphenyl carbonate (DPC) with aliphatic diols to synthesize high-molecular-weight aliphatic polycarbonates (APCs). Physical-chemical properties of these catalysts were characterized by means of different techniques to show the relationship between catalyst structure and catalytic performance. MgO prepared via simple coprecipitation method was found to be the most active catalyst among all the solid bases and magnesium compounds tested in the present study. The high-molecular-weight poly(1,4-butylene carbonate) (PBC) could be easily obtained over this MgO with M w up to 182 200 g/mol under its optimization condition. Additionally, the amplification experiment in a 5.0 L stainless steel reactor also verified the reliability of this transesterification process with MgO as catalyst, giving maximum M w value for PBC as high as 208 600 g/mol. It was found that medium and strong basic sites were responsible for this transesterification process. Simultaneously, strong basic sites also could favor the decomposition and depolymerization of the resultant PBC, leading to the decrease for M w and yield at higher temperature. In addition, based on the experimental results and relevant literature, a plausible reaction mechanism involving the activation of diols via the abstraction of proton with basic site over MgO was proposed for this process. [ABSTRACT FROM AUTHOR]

Polycarbonate diols (PCDLs) are mainly used as soft segments for the synthesis of high‐performance polyurethanes. In this work, dimethyl carbonate (DMC) and aliphatic diols are selected as reactants and CH3COONa is used as a catalyst to synthesize a series of PCDLs with different structures and different molecular weights by ester exchange polymerization reaction. The chemical structures of the PCDLs are characterized by FT‐IR, 1H NMR, and 13C NMR, and the components of the distillates in the ester exchange stage are analyzed by gas chromatography. Due to the azeotropic problem of DMC and by‐product methanol during the ester exchange process, It is difficult to design and control the reactions of PCDLs to obtain the target molecular weight products. Based on the reaction process of PCDLs, we proposed a method to design and synthesize the target molecular weight of PCDLs by using the reaction molar ratio of DMC and aliphatic diols involved in the transesterification reaction, which is not affected by the conditions of transesterification reaction and is applicable to the reactions of DMC with various diols. [ABSTRACT FROM AUTHOR]

Abstract: Functionalized isoreticular metal–organic framework-3 (IRMOF-3) was developed as a novel heterogeneous catalyst for the solventless synthesis of cyclic carbonates without any co-catalyst. The results showed that functionalized IRMOF-3 performed excellent activity, selectivity and reusability. The effects of reaction temperature, pressure, and time on the yield of propylene carbonate were tested. And the reaction mechanism was also discussed. [Copyright &y& Elsevier]

A novel La modified copper phyllosilicate nanotubes (Cu-PSNT) were designed for hydrogenation of methyl acetate (MA) to ethanol. La/Cu-PSNT catalysts were prepared by the focus on the formation of unique tubular structure and evolution of copper species by varying La loading. The physicochemical properties and distribution of the copper species were systematically studied through several characterizations. The results showed that the Cu-PSNTs catalyst exhibited superior catalytic activity in comparison with the catalyst prepared by traditional ammonia-evaporation (AE method). Moreover, the addition of La greatly influenced the dispersion of active copper species and the ratio of Cu0/(Cu0 + Cu+) through the strong interplay between copper and lanthanum species. An appropriate amount of La could increase the surface area of active copper and enhance the ability to dissociate H2 on La/Cu-PSNT catalyst, which were essential to increase the activity and stability in this hydrogenation reaction. Novel copper phyllosilicate nanotubes (Cu-PSNT) was fabricated used the hydrothermal method for hydrogenation of methyl acetate to ethanol. The nano-socketed catalyst was felicitously adjusted by doping La. The obtained the 3La/Cu-PSNT catalyst exhibited a high and stable hydrogenation ability due to its proper distribution of copper valence. [ABSTRACT FROM AUTHOR]

Dimethyl carbonate (DMC) is well known as an extremely industrially valuable substance. The demand for high-efficiency synthesis of DMC has greatly driven the exploration of novel catalysts and their low-cost preparation methods. Herein, a novel method for the rapid batch preparation of CaO/carbon catalysts using calcium citrate (CaCi) was provided, and these catalysts were used to catalyze the transesterification reaction of methanol and ethylene carbonate (EC) to synthesize DMC and ethylene glycol (EG). Accordingly, the structure and properties of the catalysts were characterized using XRD, FTIR, N2 adsorption–desorption, TG, TG-IR, CO2-TPD, XPS, SEM, TEM and ICP-OES techniques. Meanwhile, the effect of various process conditions such as carbonization temperature, reaction temperature, reaction time and catalyst amount has been extensively evaluated. Under the optimal process parameters, the conversion of EC and the selectivity of DMC and EG were 81.2, 99.3 and 99.5%, while the turnover number (TON) and turnover frequency (TOF) were 54.1 and 162 h−1, respectively. Furthermore, kinetic analysis was carried out, and the value of k (reaction rate constant) was ≈0.159 mol L−1 min−1. The reusability was also investigated. [ABSTRACT FROM AUTHOR]

Dimethyl carbonate (DMC) is an important environmentally‐friendly organic compound. The need for efficient synthesis of DMC has given a fillip to search for new catalysts and their cost‐effective preparation. In this work, a series of KAlO2/γ‐Al2O3 heterogeneous catalysts were rapidly prepared by impregnation method. These catalysts were characterized by FTIR, XRD, XPS, TG‐MS, ICP‐OES, BET and Hammett acid‐base titration and tested for the synthesis of DMC via transesterification from ethylene carbonate (EC) with methanol. The results demonstrated that KAlO2, as the active species, was produced in large quantities during the calcination process. The catalyst with a calcination temperature of 700 °C and a K2CO3 loading of 45 wt % exhibited the best catalytic activity. The optimum conditions for the process resulted in a catalyst amount of 1.0 wt %, a reaction temperature of 100 °C and a reaction time of 80 min, in which the EC conversion and DMC selectivity were 80.2 % and 98.9 %, respectively. In addition, the TON, TOF and reaction rate were 80.3, 61.2 h−1 and 3.91 gDMC⋅gcat−1⋅min−1. The reusability of the catalyst with best catalytic activity was also studied. [ABSTRACT FROM AUTHOR]

A non-petroleum approach for the catalytic synthesis of acrylic acid by hydroformylation of acetylene with carbon monoxide has been studied under various conditions. Mixtures of nickel acetate tetrahydrate, cupric bromid, triphenylphosphine and methanesulfonic acid are used as catalysts, and tetrahydrofuran as solvent. The effect of cupric bromid, triphenylphosphine and methanesulfonic acid and water on the conversion of acetylene as well as the selectivity to acrylic acid has been studied. Triphenylphosphine is found to be effient for enhancement of the selectivity under the experimental conditions. When the reaction was carried out under the total initial pressure of 6.0 MPa at the temperature of 200 °C with the catalyst composition of 2.0 mmol Ni(OAc)2 4H2O, 0.9 mmol CuBr2, 2.0 mmol CH3SO3H and 4.0 mmol PPh3, 90% conversion of acetylene and 90% selectivity to acrylic acid were achieved. [ABSTRACT FROM AUTHOR]

A circulating slurry bubble reactor was developed to synthesise methanol via methyl formate from the gas mixture of carbon monoxide and hydrogen at low temperature. The strategy for designing and scaling up the bubble reactor involved a preliminary understanding of fluid dynamics in a cold model, continuous operations under industrial conditions and a parallel experiment in an autoclave. Per-pass syngas conversion was investigated during 100-h operations. The axial profile of solid catalyst concentration was measured just before the shutdown and the composition of liquid product was analysed after the shutdown. These results show that the circulating slurry bubble column will become a potential reactor for the commercial process of low-temperature methanol synthesis after the catalyst system has been improved. [Copyright &y& Elsevier]

Dimethoxymethane was first synthesized from methanol with a liquid phase intermittent process which only used molecular oxygen as the sole oxidant. RuCl 3 was proved to be an efficient catalyst as it posses the ability of oxidizing methanol and Lewis acidic which promotes the oxidation of methanol to formaldehyde and then methanol condensed with formaldehyde to form dimethoxymethane at Lewis acid site. [ABSTRACT FROM AUTHOR]