ChemSusChem

The cover image of the January 2011 issue showcases the research of Joanna Webb, Tamara Bolaño, and Brent Gunnoe of the University of Virginia. Their Minireview on page 37 ff. outlines strategies towards the catalytic oxy-functionalization of methane and other hydrocarbons. The development of a catalyst for the controlled conversion of methane to methanol (MTM) would result in a paradigm shift for the chemical industry. Methanol can be used in fuel cells to generate electricity, can be converted to diesel fuel or gasoline, and can be used as a precursor to ethylene or propylene. Thus, the MTM process would allow natural gas to be used on a scale that is not currently conceivable.

Energy: The hydrogen economy is often proposed by media and also by some scientists as the way out from fossil fuels. Is it an achievable goal? How far are we from it? This Review makes a critical analysis of the use of hydrogen in several different technologies.

The controlled conversion of methane to methanol requires CH bond cleavage and CO bond formation. A catalytic cycle incorporating 1,2-CH-addition and net oxygen insertion with late transition metals has been proposed for this conversion. This Minireview discusses the current state of the art for each step of the proposed catalytic cycle.

Furan fluorescence: 5-Hydroxymethylfurfural, available from biomass, is efficiently oxidized to 2,5-diformylfuran by using molecular oxygen, under mild conditions. The oxidation is catalyzed by Cu(NO₃)₂/VOSO₄. The renewable, rather than petroleum-based, furan dialdehyde is used for the synthesis of a fluorescent material.

The main attraction: A magnetic solid acid with mesoporous structure was synthesized for the hydrolysis cellulose into glucose. Glucose is generated efficiently from amorphous cellulose in the mesopores of the catalyst with a yield of 50 %. Moreover, catalyst separation can be readily achieved by magnetic force.

Solid acid for biomass valorization: Phosphotungstic acid encapsulated in the metal–organic framework MIL-101 is an effective and reusable catalyst for the selective dehydration of fructose to 5-hydroxymethylfurfural, a renewable chemical platform for the production of liquid fuels and fine chemicals.

The polyoxometalate [PV₂Mo₁₀O₄₀]⁵⁻, in both acidic and ionic liquid-compatible form, acts as a catalyst for the dissolution and delignification of wood in ionic liquids, leading to faster dissolution and lower lignin content in the recovered cellulose-rich materials (isolated pulp), but also to lower lignin yields owing to the oxidation of lignin.

The preparation conditions and characterization of a perovskite niobium oxynitride, CaNbO₂N, are described. This photocatalyst, containing a band gap of 2.0 eV, produces hydrogen and oxygen from water containing an electron donor and acceptor, respectively, under irradiation with wavelengths up to 560 nm.

It′s not diamond, it′s zirconia: SO₄²⁻/ZrO₂ is an efficient catalyst for the production of levoglucosenone by fast pyrolysis of cellulose admixing catalysts. The optimal temperature for preparation of levoglucosenone is in the range of 320–350 °C. In the presence of the SO₄²⁻/ZrO₂, the levoglucosenone content of pyrolysis liquid is greatly increased at 335 °C compared to pure cellulose.

An offer you can't refuse: A bioorganic substance isolated from a composted urban refuse (AC8) is applied as sensitizer in the photodegradation of 4-chlorophenol. Production of ^⋅OH and ¹O₂ species is monitored by EPR spectroscopy and the data suggest that the role played by these species in the photodegradation process is strictly related to AC8 concentration. AC8 is thereby proven to be a photosensitizer for applications in environmental remediation.

Aluminophosphates with 8-ring window apertures: (AlPO₄-17, AlPO₄-18, AlPO₄-53, and AlPO₄-25) are synthesized and studied for CO₂ capture. Their high selectivity and hydrophobic properties at low relative humidity make them promising adsorbents for flue gas separation, at low energy costs.

The photochemical behavior of selected chlorophenols is investigated in aqueous medium in the presence of surfactants (anionic, cationic, and nonionic). Dechlorination is efficient in every case, but in micelles, clean photoreduction results independent of the surfactant used, whereas in neat water, a complex mixture of products is obtained.

RAPTA's delight: A nano-RAPTA complex supported on silica-coated ferrite nanoparticles proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentrations, water as a reaction medium, and microwaves as an energy source renders these processes green and sustainable.

Size zero waste: A clean, facile, and environment-friendly catalytic method has been developed for the conversion of furfuryl alcohol into alkyl levulinates, making use of the novel solid catalyst methylimidazolebutylsulfate phosphotungstate ([MIMBS]₃PW₁₂O₄₀). Under the optimal conditions, a high n-butyl levulinate yield of up to 93 % was obtained, with easy work-up procedures and minimal waste generation.

She sells C cells: Novel highly soluble derivatives of [70]fullerene show promising efficiencies in organic bulk heterojunction solar cells comprising the polymers MDMO-PPV and P3HT as electron donors. A clear correlation is revealed between the degree of phase separation in the fullerene/polymer blends (average cluster size) and their photovoltaic performance.

Electrolyte orchestration: Polymer membranes based on a unique ionic liquid have been prepared and characterized as electrolytes for lithium batteries. The addition of a discrete amount of a selected organic solvent mixture was found to greatly improve the ionic conductivity and the interface properties of the composite membrane in contact with lithium electrodes, thus allowing the formation of a high-performance Li-metal–polymer battery.

Ge whiz: Germanium(IV) chloride in ionic liquids catalyzes the direct conversion of carbohydrates into 5- hydroxymethylfurfural (HMF). The catalyst shows excellent activity for fructose dehydration, and a high yield of HMF up to 90 % is obtained in 5 min. This nontoxic catalytic system is also efficient for other carbohydrates such as glucose, sucrose, and even cellulose.

Sulfur atoms present in the carbon matrix increase the breakthrough capacity of dibenzothiophenes and the selectivity of dibenzothiophene adsorption owing to sulfur–sulfur and sulfur–oxygen interactions. The catalytic influence of the carbon functionality results in the oxidation of adsorbed dibenzothiophenes (see Scheme).