: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

https://chemical.eng.usm.my/bassim/PDF/photocatalytic%20degradation.pdf

Parameters affecting the photocatalytic degradation of dyes using TiO2-based photocatalysts: a review.

Rapidly increasing atmospheric CO2 concentrations threaten human society, the natural environment, and the synergy between the two. In order to ameliorate the CO2 problem, carbon capture and conversion techniques have been proposed. Metal–organic framework (MOF)-based materials, a relatively new class of porous materials with unique structural features, high surface areas, chemical tunability and stability, have been extensively studied with respect to their applicability to such techniques. Recently, it has become apparent that the CO2 capture capabilities of MOF-based materials significantly boost their potential toward CO2 conversion. Furthermore, MOF-based materials’ well-defined structures greatly facilitate the understanding of structure–property relationships and their roles in CO2 capture and conversion. In this review, we provide a comprehensive account of significant progress in the design and synthesis of MOF-based materials, including MOFs, MOF composites and MOF derivatives, and their application to carbon capture and conversion. Special emphases on the relationships between CO2 capture capacities of MOF-based materials and their catalytic CO2 conversion performances are discussed.

Carbon capture and conversion using metal–organic frameworks and MOF-based materials

CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

/pdf/recent-advances-in-the-catalytic-oxidation-of-volatile-zw2c35dbg7.pdf

Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.

Effect of copper compounds on the catalytic activity of n-Bu2SnO in the transesterification of dimethyl carbonate and phenol to diphenyl carbonate was investigated. The results showed that they as promoters could obviously enhance the activity of n-Bu2SnO except for Cu. The characterizations of X-ray diffraction (XRD) identified that CuO could be reduced to Cu, and Cu2O was stable. When the reaction was carried out between 150 and 180 oC, with molar ratio of n-Bu2SnO to Cu2O of 8:1, catalyst amount 0.0067, reaction time 10h, molar ratio of dimethyl carbonate to phenol of 3:1, the phenol conversion and the transesterification selectivity were 60.3% and 99.2%, respectively. In the transesterification, the acid-base synergistic effect between Cu2O as the basic promoter and n-Bu2SnO as the Lewis acid resulted in the active enhancement of n-Bu2SnO. Moreover the performance of Cu2O remained unchanged for seven times reuse.

Effect of Copper Compounds on the Synthesis of Diphenyl Carbonate from Transesterification Catalyzed by n-Bu2SnO

Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate) Using Alkali Metals as Catalysts

Studies on synthesis and optical properties of poly(isosorbide-co-1,4-cyclohexanedimethanol) carbonate

Ionic liquids (ILs) have garnered increasing attention in the biomedical field due to their unique properties. Although significant research has been conducted in recent years, there is still a lack of understanding of the potential applications of ILs in the biomedical field and the underlying principles. To identify the antibacterial activity and mechanism of ILs on bacteria, we evaluated the antimicrobial potency of imidazole chloride ILs (CnMIMCl) on Staphylococcus aureus (S. aureus). The toxicity of ILs was positively correlated to the length of the imidazolidinyl side chain. We selected C12MIMCl to study the mechanism of S. aureus. Through the simultaneous change in the internal and external parts of S. aureus, C12MIMCl caused the death of the bacteria. The production of large amounts of reactive oxygen species (ROS) within the internal parts stimulated oxidative stress, inhibited bacterial metabolism, and led to bacterial death. The external cell membrane could be destroyed, causing the cytoplasm to flow out and the whole cell to be fragmented. The antibacterial effect of C12MIMCl on skin abscesses was further verified in vivo in mice.

/pdf/the-antibacterial-activity-and-mechanism-of-imidazole-3ij940be.pdf

The antibacterial activity and mechanism of imidazole chloride ionic liquids on Staphylococcus aureus

For acid-catalyzed chemical reactions with forming isomers of the target product, the isomer by-products cannot be well inhibited only by adjusting the acid properties. At this point, it is an effective strategy to design functional acid catalysts to decrease by-products through increasing the steric hindrance of forming isomer by-products. In this paper, thiol and trifluoromethanesulfonyl functional sulfonated mesoporous polydivinylbenzene solid acids were prepared. The Bisphenol-A synthesis reaction was used as a probe reaction to verify the cooperative effect of thiol and trifluoromethanesulfonyl on the catalytic performance of prepared solid acids. The results confirmed that thiol functionalizing sulfonated mesoporous polydivinylbenzene solid acid could reduce the by-product o′p-bisphenol-A through steric hindrance effect and then improved the selectivity of the target product p′p-bisphenol-A. Trifluoromethanesulfonyl functionalizing sulfonated mesoporous polydivinylbenzene could promote the catalytic efficiency and the selectivity of p′p-bisphenol-A by enhancing the acidity of solid acids. Thiol and trifluoromethanesulfonyl difunctional sulfonated mesoporous polydivinylbenzene (PDVB-SO2CF3-SO3H-SH) had the optimal catalytic performance due to the cooperative effect of steric hindrance and strong acidity. The phenol conversion of 37 % and the p′p-bisphenol-A selectivity of 97 % were obtained over PDVB-SO2CF3-SO3H-SH under 90 °C for 4 h. 

An Efficient Thiol and Trifluoromethanesulfonyl Difunctional Sulfonated Mesoporous Polydivinylbenzene Solid Acid: Cooperative Effect of Steric Hindrance and Acidity

Gongying Wang

Papers

Effect of Copper Compounds on the Synthesis of Diphenyl Carbonate from Transesterification Catalyzed by n-Bu2SnO

Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate) Using Alkali Metals as Catalysts

Studies on synthesis and optical properties of poly(isosorbide-co-1,4-cyclohexanedimethanol) carbonate

The antibacterial activity and mechanism of imidazole chloride ionic liquids on Staphylococcus aureus

An Efficient Thiol and Trifluoromethanesulfonyl Difunctional Sulfonated Mesoporous Polydivinylbenzene Solid Acid: Cooperative Effect of Steric Hindrance and Acidity