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We have successfully isolated and characterized the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) (1; phen=1,10‐phenanthroline), formed as an intermediate during the Zn(OAc)2/phen‐catalyzed synthesis of organic carbamates from CO2, amines, and the reusable reactant Si(OMe)4. Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe)4 proceeds via a five‐coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe)4 as the reaction solvent and additives like KOMe and KF, which promote the formation of the five‐coordinated silicon species. This sustainable and effective method can be used to synthesize various N‐aryl and N‐alkyl carbamates, including industrially important polyurethane raw materials, starting from CO2 under atmospheric pressure. [ABSTRACT FROM AUTHOR]

To reduce anthropogenic carbon dioxide (CO2) emissions, it is desirable to develop reactions that can efficiently convert low concentrations of CO2, present in exhaust gases and ambient air, into industrially important chemicals, without involving any expensive separation, concentration, compression, and purification processes. Here, we present an efficient method for synthesizing urea derivatives from alkyl ammonium carbamates. The carbamates can be easily obtained from low concentrations of CO2 as present in ambient air or simulated exhaust gas. Reaction of alkyl ammonium carbamates with 1,3-dimethyl-2-imidazolidinone solvent in the presence of a titanium complex catalyst inside a sealed vessel produces urea derivatives in high yields. This reaction is suitable for synthesizing ethylene urea, an industrially important chemical, as well as various cyclic and acyclic urea derivatives. Using this methodology, we also show the synthesis of urea derivatives directly from low concentration of CO2 sources in a one-pot manner. Upconverting anthropogenic CO2 into valuable chemicals generally involves separation and concentration steps of the feed gas. Here, the authors report an efficient, one-pot method for synthesizing urea derivatives from alkyl ammonium carbamates obtained from atmospheric CO2 or simulated exhaust gas with low concentrations of CO2. [ABSTRACT FROM AUTHOR]

New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO2 and alcohols. Using tetraethyl orthosilicate (TEOS) and CO2 with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS. Under the same conditions, DEC can be synthesized using a wide range of alkoxysilane substrates by investigating the effects of the number of ethoxy substituent in alkoxysilane substrates, alkyl chain, and unsaturated moiety on the fundamental property of this reaction. Mechanistic insights obtained by kinetic studies, labeling experiments, and spectroscopic investigations reveal that DEC is generated via nucleophilic ethoxylation of a CO2‐inserted Zr catalyst and catalyst regeneration by TEOS. The unprecedented transformation offers a new approach toward a cleaner route for DEC synthesis using recyclable alkoxysilane. [ABSTRACT FROM AUTHOR]

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]

Amines, carbon dioxide fixation, density functional calculations, sustainable chemistry, zinc Cover Feature: N-Aryl and N-Alkyl Carbamates from 1 Atmosphere of CO2 (Chem. Eur. J. 72/2021) Keywords: amines; carbon dioxide fixation; density functional calculations; sustainable chemistry; zinc EN amines carbon dioxide fixation density functional calculations sustainable chemistry zinc 17974 17974 1 12/27/21 20211223 NES 211223 B We have successfully isolated b the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) ( B 1 b , phen=1,10-phenanthroline), which is an intermediate in the Zn(OAc) SB 2 sb /phen-catalyzed synthesis of organic carbamates from CO SB 2 sb , amines, and Si(OMe) SB 4 sb . [Extracted from the article]

Keywords: alkoxysilane; carbon dioxide; diethyl carbonate; sustainable catalytic synthesis; Zr catalysts EN alkoxysilane carbon dioxide diethyl carbonate sustainable catalytic synthesis Zr catalysts 755 755 1 02/17/21 20210205 NES 210205 B The Cover Feature b shows the new synthesis of diethyl carbonate from CO SB 2 sb and alkoxysilanes using a zirconium catalyst. Alkoxysilane, carbon dioxide, diethyl carbonate, sustainable catalytic synthesis, Zr catalysts. [Extracted from the article]

A novel solution-processable low molecular weight organic semiconductor material TS-5, which has high thermal stability and solubility with various aromatic solvents, was developed. Field effect transistors (FET) fabricated using TS-5 as an active layer, exhibited p-type transistor responses with mobilities greater than 1.0 cm2/Vs and are stable at 150°C in air condition. [ABSTRACT FROM AUTHOR]