Addition of Imidazolium-Based Ionic Liquid to Improve Methanol Production in Polyamine-Assisted CO Capture and Conversion Systems Using Pincer Catalysts.

Ionic liquids have been studied as CO capture agents. However, they are rarely used in combined CO capture and conversion processes. Utilizing imidazolium-based ionic liquids, the conversion of CO to methanol was greatly improved in polyamine assisted systems catalyzed by homogeneous pincer catalysts with Ru and Mn metal centers.

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/AlO Catalyst.

Increasing carbon dioxide emissions has sparked a growing interest in capturing these emissions at the source of their release. For such processes, amines can be used as carbon dioxide capture agents. Herein, CO was captured under ambient conditions using solutions of amines and polyamines in ethylene glycol.

Homogeneous Hydrogenation of CO and CO to Methanol: The Renaissance of Low-Temperature Catalysis in the Context of the Methanol Economy.

The traditional economy based on carbon-intensive fuels and materials has led to an exponential rise in anthropogenic CO emissions. Outpacing the natural carbon cycle, atmospheric CO levels increased by 50 % since the pre-industrial age and can be directly linked to global warming. Being at the core of the proposed methanol economy pioneered by the late George A.

Tertiary Amine-Ethylene Glycol Based Tandem CO Capture and Hydrogenation to Methanol: Direct Utilization of Post-Combustion CO.

Carbon dioxide capture using tertiary amines in ethylene glycol solvent was performed under ambient conditions. Subsequently, the CO captured as alkyl carbonate salts was successfully hydrogenated to methanol, in the presence of H gas and Ru-Macho-BH catalyst. A comprehensive series of tertiary amines were selected for the integrated capture and conversion process.

Hydroxide Based Integrated CO Capture from Air and Conversion to Methanol.

The first example of an alkali hydroxide-based system for CO capture and conversion to methanol has been established. Bicarbonate and formate salts were hydrogenated to methanol with high yields in a solution of ethylene glycol. In an integrated one-pot system, CO was efficiently captured by an ethylene glycol solution of the base and subsequently hydrogenated to CHOH at relatively mild temperatures (100-140 °C) using Ru-PNP catalysts.

Integrated CO Capture and Conversion to Formate and Methanol: Connecting Two Threads.

The capture of CO from concentrated emission sources as well as from air represents a process of paramount importance in view of the increasing CO concentration in the atmosphere and its associated negative consequences on the biosphere. Once captured using various technologies, CO is desorbed and compressed for either storage (carbon capture and storage (CCS)) or production of value-added products (carbon capture and utilization (CCU)). Among various products that can be synthesized from CO, methanol and formic acid are of high interest because they can be used directly as fuels or to generate H on demand at low temperatures (<100 °C), making them attractive hydrogen carriers (12.

Catalytic Homogeneous Hydrogenation of CO to Methanol via Formamide.

A novel amine-assisted route for low temperature homogeneous hydrogenation of CO to methanol is described. The reaction proceeds through the formation of formamide intermediates. The first amine carbonylation part is catalyzed by KPO.

Combined CO Capture and Hydrogenation to Methanol: Amine Immobilization Enables Easy Recycling of Active Elements.

Amines were immobilized onto solid supports and employed for tandem CO capture and conversion to CH OH using homogeneous hydrogenation catalysts. The hydrogenation proceeded through the formation of formamide intermediates. After hydrogenation, the immobilized amines were easily filtered and collected to be reused.

Oxidation-Resistant, Cost-Effective Epoxide-Modified Polyamine Adsorbents for CO Capture from Various Sources Including Air.

CO adsorbents based on the reaction of pentaethylenehexamine (PEHA) or tetraethylenepentamine (TEPA) with propylene oxide (PO) were easily prepared in "one pot" by impregnation on a silica support in water. The starting materials were readily available and inexpensive, facilitating the production of the adsorbents on a large scale. The prepared polyamine/epoxide adsorbents were efficient in capturing CO and could be regenerated under mild conditions (50-85 °C).

Mechanistic Insights into Ruthenium-Pincer-Catalyzed Amine-Assisted Homogeneous Hydrogenation of CO to Methanol.

Amine-assisted homogeneous hydrogenation of CO to methanol is one of the most effective approaches to integrate CO capture with its subsequent conversion to CHOH. The hydrogenation typically proceeds in two steps. In the first step the amine is formylated via an in situ formed alkylammonium formate salt (with consumption of 1 equiv of H).

A Carbon-Neutral CO Capture, Conversion, and Utilization Cycle with Low-Temperature Regeneration of Sodium Hydroxide.

A highly efficient recyclable system for capture and subsequent conversion of CO to formate salts is reported that utilizes aqueous inorganic hydroxide solutions for CO capture along with homogeneous pincer catalysts for hydrogenation. The produced aqueous solutions of formate salts are directly utilized, without any purification, in a direct formate fuel cell to produce electricity and regenerate the hydroxide base, achieving an overall carbon-neutral cycle. The catalysts and organic solvent are recycled by employing a biphasic solvent system (2-MTHF/HO) with no significant decrease in turnover frequency (TOF) over five cycles.

Integrative CO Capture and Hydrogenation to Methanol with Reusable Catalyst and Amine: Toward a Carbon Neutral Methanol Economy.

Herein we report an efficient and recyclable system for tandem CO capture and hydrogenation to methanol. After capture in an aqueous amine solution, CO is hydrogenated in high yield to CHOH (>90%) in a biphasic 2-MTHF/water system, which also allows for easy separation and recycling of the amine and catalyst for multiple reaction cycles. Between cycles, the produced methanol can be conveniently removed in vacuo.

Efficient Reversible Hydrogen Carrier System Based on Amine Reforming of Methanol.

A novel hydrogen storage system based on the hydrogen release from catalytic dehydrogenative coupling of methanol and 1,2-diamine is demonstrated. The products of this reaction, N-formamide and N,N'-diformamide, are hydrogenated back to the free amine and methanol by a simple hydrogen pressure swing. Thus, an efficient one-pot hydrogen carrier system has been developed.

Conversion of CO2 from Air into Methanol Using a Polyamine and a Homogeneous Ruthenium Catalyst.

A highly efficient homogeneous catalyst system for the production of CH3OH from CO2 using pentaethylenehexamine and Ru-Macho-BH (1) at 125-165 °C in an ethereal solvent has been developed (initial turnover frequency = 70 h(-1) at 145 °C). Ease of separation of CH3OH is demonstrated by simple distillation from the reaction mixture. The robustness of the catalytic system was shown by recycling the catalyst over five runs without significant loss of activity (turnover number > 2000).

Single Step Bi-reforming and Oxidative Bi-reforming of Methane (Natural Gas) with Steam and Carbon Dioxide to Metgas (CO-2H2) for Methanol Synthesis: Self-Sufficient Effective and Exclusive Oxygenation of Methane to Methanol with Oxygen.

Catalysts based on suitable metal oxide supports, such as NiO/MgO and CoO/MgO, were shown to be active for single step bi-reforming, the combined steam and dry reforming of methane or natural gas with H2O and CO2 exclusively to metgas (CO-2H2) for efficient methanol synthesis. Reactions were carried out in a tubular flow reactor under pressures up to 42 bar at 830-910 °C. Using a CH4 to steam to CO2 ratio of ∼3:2:1 in the gas feed, the H2/CO ratio of 2:1 was achieved, which is desired for subsequent methanol synthesis.

Amine-free reversible hydrogen storage in formate salts catalyzed by ruthenium pincer complex without pH control or solvent change.

Due to the intermittent nature of most renewable energy sources, such as solar and wind, energy storage is increasingly required. Since electricity is difficult to store, hydrogen obtained by electrochemical water splitting has been proposed as an energy carrier. However, the handling and transportation of hydrogen in large quantities is in itself a challenge.

Recycling of carbon dioxide to methanol and derived products - closing the loop.

Starting with coal, followed by petroleum oil and natural gas, the utilization of fossil fuels has allowed the fast and unprecedented development of human society. However, the burning of these resources in ever increasing pace is accompanied by large amounts of anthropogenic CO2 emissions, which are outpacing the natural carbon cycle, causing adverse global environmental changes, the full extent of which is still unclear. Even through fossil fuels are still abundant, they are nevertheless limited and will, in time, be depleted.

Easily regenerable solid adsorbents based on polyamines for carbon dioxide capture from the air.

Adsorbents prepared easily by impregnation of fumed silica with polyethylenimine (PEI) are promising candidates for the capture of CO2 directly from the air. These inexpensive adsorbents have high CO2 adsorption capacity at ambient temperature and can be regenerated in repeated cycles under mild conditions. Despite the very low CO2 concentration, they are able to scrub efficiently all CO2 out of the air in the initial hours of the experiments.

Self-sufficient and exclusive oxygenation of methane and its source materials with oxygen to methanol via metgas using oxidative bi-reforming.

A combination of complete methane combustion with oxygen of the air coupled with bi-reforming leads to the production of metgas (H2/CO in 2:1 mole ratio) for exclusive methanol synthesis. The newly developed oxidative bi-reforming allows direct oxygenation of methane to methanol in an overall economic and energetically efficient process, leaving very little, if any, carbon footprint or byproducts.

Bi-reforming of methane from any source with steam and carbon dioxide exclusively to metgas (CO-2H2) for methanol and hydrocarbon synthesis.

A catalyst based on nickel oxide on magnesium oxide (NiO/MgO) thermally activated under hydrogen is effective for the bi-reforming with steam and CO(2) (combined steam and dry reforming) of methane as well as natural gas in a tubular flow reactor at elevated pressures (5-30 atm) and temperatures (800-950 °C). By adjusting the CO(2)-to-steam ratio in the gas feed, the H(2)/CO ratio in the produced syn-gas could be easily adjusted in a single step to the desired value of 2 for methanol and hydrocarbon synthesis.

Carbon dioxide capture from the air using a polyamine based regenerable solid adsorbent.

Easy to prepare solid materials based on fumed silica impregnated with polyethylenimine (PEI) were found to be superior adsorbents for the capture of carbon dioxide directly from air. During the initial hours of the experiments, these adsorbents effectively scrubbed all the CO(2) from the air despite its very low concentration. The effect of moisture on the adsorption characteristics and capacity was studied at room temperature.

Anthropogenic chemical carbon cycle for a sustainable future.

Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time, millions of years, can new fossil fuels be formed naturally. The burning of our diminishing fossil fuel reserves is accompanied by large anthropogenic CO(2) release, which is outpacing nature's CO(2) recycling capability, causing significant environmental harm.

Hydrogen generation from formic acid decomposition by ruthenium carbonyl complexes. Tetraruthenium dodecacarbonyl tetrahydride as an active intermediate.

The present Minireview covers the formation and the structural characterization of noble metal carbonyl and hydrido carbonyl complexes, with particular emphasis on ruthenium complexes using formic acid as a carbonyl and hydride source. The catalytic activity of these organometallic compounds for the decarboxylation of formic acid, a potential hydrogen storage material, is also reviewed. In addition, the first preparation of [Ru(4)(CO)(12)H(4)] from RuCl(3) and formic acid as well as the catalytic activity of [Ru(4)(CO)(12)H(4)] for the decomposition of formic acid to hydrogen and carbon dioxide are presented.

Chemical recycling of carbon dioxide to methanol and dimethyl ether: from greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons.

Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time can new fossil fuels be formed naturally. In contrast, chemical recycling of carbon dioxide from natural and industrial sources as well as varied human activities or even from the air itself to methanol or dimethyl ether (DME) and their varied products can be achieved via its capture and subsequent reductive hydrogenative conversion.

Chiral benzylic carbocations: low-temperature NMR studies and theoretical calculations.

The alpha-chiral secondary and tertiary benzylic carbocations 19-30 were generated from the corresponding benzylic alcohols 1, 2, and 5-14 by treatment with FSO(3)H or FSO(3)H/SbF(5) in SO(2)ClF as the solvent at -70 degrees C and characterized by one- and two-dimensional NMR spectroscopy. Coupling constants and NOESY measurements suggest a preferred conformation in which the alpha-hydrogen atom occupies the 1,3-allylic-strain position and the diastereotopic faces of the cations are differentiated by the alkyl substituent and a functional group (FG). The existence of this preferred conformation is further supported by calculations using a DFT method at the B3LYP/6-311+G** level.