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The combination catalyst of CeO2 and H-FAU zeolite was effective for the direct synthesis of diethyl carbonate from CO2 and ethanol with 2,2-diethoxypropane as a dehydrating regent, where H-FAU catalyzed hydrolysis of 2,2-diethoxypropane. The combination catalyst provided high activity and a high diethyl carbonate yield of 72% based on 2,2-diethoxypropane at a low temperature of 393 K. [ABSTRACT FROM AUTHOR]

The harmless treatment and resource utilization of the high boiling chlorosilane produced by products in the process of polycrystalline silicon production can be realized by using organic amine catalyst. The effects of reaction temperature and catalyst type on the catalytic cracking of high-boiling chlorosilane was investigated and the reaction mechanism was analyzed. The results showed that, using N,N-dimethylbenzylamine as the catalyst, at a reaction temperature of 130 ~ 135 °C, a reaction time of 1.5 h, and a catalyst amount of 8%, the yield of monosilane product could reach 79.99%. [ABSTRACT FROM AUTHOR]

A coordination polymeric crystal 1 was successfully synthesized from H 4 L (5,5′-(1,4-phenylenebis (methoxy))diisophthalic acid), bidpe (4,4′-bis(lmidazolyl)diphenyl ether), and Zn(NO 3) 2 ·6H 2 O under solvothermal conditions, and characterized by single-crystal X-ray diffraction. Then, two new crystals 1 Fe and 1 Cu were obtained with metal ion exchange when 1 was dipped into the DMF solution for FeCl 2 and CuCl 2 , respectively. The exchange process demonstrated that the high valence metal ion with strong acidity could be destroyed the structure of the crystals. Therefore, it should be exchanged with lower valence ion and then oxidized to the high valence state, which could be a feasible way to obtain the crystals with high valence metal ions. Further, the magnetic property and the synergistic CO 2 conversion with epoxide for 1 Fe and 1 Cu were also investigated, and the results shown that 1 Fe could be regarded as a potential catalyst for this conversion. Three two dimensional two-fold interpenetrated MOFs 1 , 1 Fe and 1 Cu were successfully synthesized via solvothermal or post-synthetic modification. 1 Fe and 1 Cu shown excellent abilities for catalyzed cycloaddition of CO 2 to epoxides. [Display omitted] 1. Three novel dimensional MOFs 1 , 1 Fe and 1 Cu , have been synthesized via solvent-thermal treatment and post-synthetic exchange approach. 2. Zn(II) ions were exchange with Fe(III) ions in 1 Fe. But, due to the strong acidity of Fe(III) ions could destroy the crystal framework, the exchange only could be happen when 1 was dipped into the freshly FeCl 2 -DMF solution. 3. Variable-temperature magnetic studies indicate that 1 Fe contains the weak ferromagnetic chain while 1 Cu contains the weak antiferromagnetic (AF) interactions. 4. The catalytic properties of 1 , 1 Fe and 1 Cu for epoxides' cycloaddition reactions with CO 2 , and the results shown that 1 Fe and 1 Cu could be good catalysts for this reaction. [ABSTRACT FROM AUTHOR]

Abstract: Novel and high efficient catalysts of metal porphyrin (M(TPP)X, M=Co, Fe, Ru, Mn; X=Cl−, Br−, OAc−, OTs−, Cl3CCO2 −)/phenyltrimethylammonium tribromide (PTAT) were developed to catalyze the coupling reaction of carbon dioxide and epoxides at room temperature. [Copyright &y& Elsevier]

• Co-Salen complexes containing different groups and bearing potassium iodide (KI) complexed with crown ether (K@SCs) were prepared. • Salen derivative organic polymer as heterogeneous catalyst for CO 2 cycloaddition reaction. • Alkali metal halides and Lewis acids have good synergistic effects in catalytic reactions. Metallosalen presents very important applications in both homogenous and heterogeneous catalysis. Correspondingly, porous polymeric metallosalen combined with the performance of organometallics and heterogeneous polymers possess potential in CO 2 fixation reactions. Herein, a family collection of K@SCs were conceived and obtained by combining cobalt-salen complexes with different groups and diaminobenzene-18-crown-6 complexed with KI, which allows multiphase catalytic immobilization of CO 2 to epoxides. Catalyst K@SC-3 can fix CO 2 into a variety of substituted epoxides in >90% yields to the corresponding cyclic carbonates in co-catalyst-free and solvent-free conditions. Furthermore, K@SC-3 can be recovered and reused at least six times by simple centrifugal separation, demonstrating superior stability. The kinetics experiments were also carried out at varied temperatures catalyzed by K@SC-3. It is concluded that a first-order equation of epoxide was proved and the activation energy was calculated to be 27.13 KJ/mol. [Display omitted] [ABSTRACT FROM AUTHOR]

• The Tröger base analogue coordinated with potassium iodide and containing crown ether CATB-KI was fabricated. • The acidified CATB-KIs shown high catalytic efficiency to cyclic carbonates. • The synergistic mechanism has been proved in terms of experimental results and calculation of dynamics. Tröger's bases (TB) containing two steric nitrogen atoms, are alternated as building block for constructing molecular acceptors to form covalent bonds with acids, making TB a promising catalyst. Herein, TB analogs fabricated with crown ethers were knitted by condensation reaction and combined with potassium iodide as a brand-new catalytic system (CATB-KIs), which were characterized using FT-IR, 13C CP MAS NMR, SEM, TGA, and XPS spectroscopy respectively. The generated CATB-KIs exhibited excellent performance for CO 2 fixation reaction with epoxides to produce cyclic carbonates under mild conditions, and the catalytic activity could be further improved by coordinating with acids beforehand, in which HBr performs fascinated activity. After 12 h, the corresponding cyclic carbonate from epichlorohydrin with 95.1% yield was detected at mild conditions with solvent-free in the presence of CATB-KI-2 and HBr. A series of terminal epoxides were converted into desired cyclic carbonates with desirable yields. The catalyst could be recovered successfully and reused six times without significant loss of activity. Finally, dynamics study on catalytic mechanism has been accomplished and the activated energy was calculated as 72.1 kJ/mol. A synergistic catalytic mechanism of hydrogen bonding and I anion has been proposed to account for the excellent catalytic activity of this catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• Density functional theory study of hydrogenation of CO 2 to methanol catalyzed by iron bipyridinol complexes. • An unexpected three-site metal-ligand cooperation (MLC) mechanism for the breaking of C–O and O–H bonds and the formation of O–H...O hydrogen bonds. • The essential role of the bipyridinol ligand with hydroxyl groups for hydrogenation reactions. A density functional theory study of Fe-catalyzed hydrogenation of CO 2 to methanol reveals an unexpected metal–ligand cooperation mechanism with two ortho -OH groups play key roles for the breaking of C–O and O–H bonds and formation of O–H...O hydrogen bonds. The formation of methanediol via hydride transfer from Fe to formic acid (4′ → TS 6,7) is the rate-determining step with a total barrier of 30.8 kcal mol−1 in free energy. Furthermore, by replacing the two meta (R 1) and two para (R 2) hydrogen atoms in the bipyridinol ligand and the coordinated CN and CO with different functional groups, we built a series of stable iron complexes and computationally predicted their catalytic activities for hydrogenation of CO 2 to methanol. Among all newly proposed iron complexes, 1t and 1u are promising catalyst candidates for hydrogenation of CO 2 to methanol with rather low total free energy barriers of 26.6 and 28.8 kcal mol−1, respectively. The electrostatic potential map analysis indicates that stronger electron donating ligands on iron may lead to higher catalytic activities. DFT calculations reveal an unexpected metal–ligand cooperation mechanism with two ortho -OH groups play key roles for the breaking of C–O and O–H bonds and formation of O–H...O hydrogen bonds. [Display omitted] [ABSTRACT FROM AUTHOR]

• Density functional theory study of hydrogenation of CO 2 to methanol catalyzed by iron bipyridinol complexes. • An unexpected three-site metal-ligand cooperation (MLC) mechanism for the breaking of C–O and O–H bonds and the formation of O–H...O hydrogen bonds. • The essential role of the bipyridinol ligand with hydroxyl groups for hydrogenation reactions. A density functional theory study of Fe-catalyzed hydrogenation of CO 2 to methanol reveals an unexpected metal–ligand cooperation mechanism with two ortho -OH groups play key roles for the breaking of C–O and O–H bonds and formation of O–H...O hydrogen bonds. The formation of methanediol via hydride transfer from Fe to formic acid (4′ → TS 6,7) is the rate-determining step with a total barrier of 30.8 kcal mol−1 in free energy. Furthermore, by replacing the two meta (R 1) and two para (R 2) hydrogen atoms in the bipyridinol ligand and the coordinated CN and CO with different functional groups, we built a series of stable iron complexes and computationally predicted their catalytic activities for hydrogenation of CO 2 to methanol. Among all newly proposed iron complexes, 1t and 1u are promising catalyst candidates for hydrogenation of CO 2 to methanol with rather low total free energy barriers of 26.6 and 28.8 kcal mol−1, respectively. The electrostatic potential map analysis indicates that stronger electron donating ligands on iron may lead to higher catalytic activities. DFT calculations reveal an unexpected metal–ligand cooperation mechanism with two ortho -OH groups play key roles for the breaking of C–O and O–H bonds and formation of O–H...O hydrogen bonds. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Several chiral BINADCo(III)X (BINAD=Bis(1,1′-2-hydroxy-2′-alkoxy-3-naphthylidene)-1,2-cyclohexanediamine, X=OAc, CF3CO2, CCl3CO2, OTs, p-NO2PhCO2) complexes were synthesized and used to catalyze the asymmetric cycloaddition of carbon dioxide with epoxides under mild condition to afford chiral cyclic carbonates. The best catalyst of (S,S,S,S)-BINADCo(III)(OAc) 9b and phenyltrimethylammonium tribromide (PTAT) can provide propylene carbonate with the highest ee being 95% at −20°C. [Copyright &y& Elsevier]