: 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.

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

Molybdosphoric Acid Mixed with Titania Used as a Catalyst to Synthesize Diphenyl Carbonate via Transesterification of Dimethyl Carbonate and Phenol

Mg-Al mixed oxides with different Mg/Al molar ratio were prepared by thermal decomposition of hydrotalcitelike precursors at 500 °C for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with 1,4-butanediol to synthesize high-molecular-weight poly(butylene carbonate) (PBC). The structure-activity correlations of these catalysts in this transesterification process were discussed by means of various characterization techniques. It was found that the chain growth for the formation of PBC can only be obtained through connecting ―OH and ―OC(C)OC6H5 end-group upon removing the generated phenol, and the sample with Mg/Al molar ratio of 4.0 exhibited the best catalytic performance, giving PBC with Mw of 1.64 × 105 g/mol at 210 °C for 3.0 h. This excellent activity depended mainly on the specific surface area and basicity rather than pore structure or crystallite size of MgO.

Structure-activity correlations of calcined Mg-Al hydrocalcites for aliphatic polycarbonate synthesis via transesterification process

Improved processability and optimized preparing process for fire‐safe poly (ethylene terephthalate) by electron effect modified Schiff base

The invention relates to an organic titanium catalyst for an exchange reaction of dimethyl carbonate and phenol ester The catalyst is composed of titanium oxyacelate formed through coordination of titanium and an acetate radical, and a solvothermal method is adopted to solve the catalyst and mainly solves the problems of difficult catalyst separation and recovery and low ester exchange activity The organic titanium catalyst prepared through the method has a high catalysis effect on a reaction for synthesizing diphenyl carbonate through an ester exchange process, and allows the phenol conversion rate to reach 478% and the ester exchange selectivity to reach above 999% The catalyst has the advantages of cheap and easily available raw materials, simple preparation method, insolubility in a reaction system, easy separation and recovery from the reaction system after the reaction, and repeated use

Organic titanium catalyst for exchange reaction of dimethyl carbonate and phenol ester

Mg–Al hydrotalcites were prepared by the forward, reverse and simultaneous titration coprecipitation methods, respectively. The effects of coprecipitation method on Mg–Al hydrotalcite properties were investigated. The resulting catalysts were evaluated for their performance in the synthesis of diethylene glycol di-(methyl carbonate). The results showed that there were no other crystalline phases, but a Mg–Al hydrotalcite structure in any of the samples and HTS prepared by the simultaneous titration method had the best crystallinity. Only the Mg–Al hydrotalcites prepared by the forward and simultaneous titration coprecipitation methods had a similar Mg/Al ratio as with the salt solution. The coprecipitation method affected the pore structure, specific surface area and basicity distribution of Mg–Al hydrotalcite and thus affected its catalytic performance. HTS, which had a relatively small pore size, moderate specific surface area and considerable basicity, displayed superior catalytic performance (91.6% yield) under optimized conditions. The catalyst could be easily separated and reused. Its activity did not decrease apparently, and the yield of target product maintained around 90% after five circles.

Gongying Wang

Papers

Molybdosphoric Acid Mixed with Titania Used as a Catalyst to Synthesize Diphenyl Carbonate via Transesterification of Dimethyl Carbonate and Phenol

Structure-activity correlations of calcined Mg-Al hydrocalcites for aliphatic polycarbonate synthesis via transesterification process

Improved processability and optimized preparing process for fire‐safe poly (ethylene terephthalate) by electron effect modified Schiff base

Organic titanium catalyst for exchange reaction of dimethyl carbonate and phenol ester

Effect of coprecipitation method on Mg–Al hydrotalcite properties: application in the synthesis of diethylene glycol di-(methyl carbonate)