Oxazolidinones have been synthesized by reacting glycerol carbonate or glycerol with urea in the presence of gamma-Zr phosphate as a catalyst. The conversion yield of the polyol or its carbonate depends on the temperature. Below 408 K the selectivity is 100% with a conversion of up to 25%, whereas increasing the temperature means that conversion yield grows, but the selectivity decreases, which makes the separation process more difficult. Starting from glycerol carbonate, two isomers, 6 and 6', are formed with a quasi 1:1 molar ratio because urea can attack the carbonate moiety on both sides of the carboxylic CO moiety. From glycerol the formation of the 6' isomer is preferred: the ratio of 6'/6 is close to 7. The oxazolidinones formed act as templates because they interact through hydrogen bonding with glycerol. The intensity of the interaction depends on the 6 or 6' isomer: DFT calculations showed that the energy was 22.6 kcalmol(-1) for 6-oxazolidinone and 25.7 kcalmol(-1) for 6'-oxazolidinone.

Glycerol carbonate, synthesised via a non-phosgene route using glycerol and CO2 or urea in presence of a heterogeneous catalyst, was efficiently converted into a series of derivatives through the functionalization of the eOH moiety, using high yield, high selectivity synthetic routes not affecting the carbonate functionality. So, for example, glycerol carbonate was converted into epichlorohydrin, a product that has a large industrial application, under very mild conditions, using a two-step reaction with a 98% yield and 100% selectivity. The high yield and mild reaction conditions (very often close to the ambient conditions) make the environmentally friendly synthetic approach described in this work of potential applicative interest. All compounds prepared were fully characterized.

In this paper, we present the results of a study on 5-HMF production from fructose by means of heterogeneous catalysts in aqueous media. Mild conditions were used, setting the temperature between 393 K and 443 K. Cerium(iv) phosphates, different from other metal(iv)-phosphates, such as titanium and zirconium, have been characterized only recently. Ce-phosphates are quite complex structures as they show several arrangements. They undergo leaching of the phosphate group as phosphoric acid with consequent slow de-activation of the catalysts. The leaching rate depends on the nature and on the temperature of the calcination of the original phosphates. This opened the question whether the conversion was driven by the heterogeneous catalysts or by the soluble phosphoric acid. A specific test has demonstrated that the solid catalysts are responsible for the conversion of fructose into 5-HMF, more than the liquid phase. We have also demonstrated that the leached phosphate is substituted by fructose on the solid catalyst. A best yield of 52% with selectivity of 93% in batch and 24% in a flow reactor at 443 K (single pass) with a selectivity also >95% were obtained.

Chemical reducing agents (sodium dithionite) or bioglycerol (as H and e−-donor under irradiation in the presence of ZnS-A as photocatalyst) are able to back-convert NAD+ into NADH, which is used as e−-donor in the enzymatic reduction of CO2 into CH3OH. In doing so, the molar ratio CH3OH/CO2 has been increased (without recycling of NAD+) using the photocatalyst

CO2 can be converted into methanol, through the intermediate steps of reduction to formic acid and formaldehyde using a triad of enzymes such as formate dehydrogenase (FatoDH), formaldehyde dehydrogenase (FaldDH) and alcohol dehydrogenase (ADH). In each reductive step one mole of NADH is oxidized to NAD+ that has to be converted back to NADH in order to make the process acceptable from an economic point of view. Such regeneration can be accomplished by chemical, electrochemical, photochemical or photoelectrochemical processes. We have recently shown[1] that the photosystems can be coupled with the three enzymes listed above for the reduction of CO2 to methanol, using glycerol as H-donor. New photocatalysts have been prepared, such as: transition metal sulphides and nonstoichiometric mixed sulphides, composites of metal oxides like Cu2O/TiO2. Here, we describe the behaviour of selected semiconductors and the working mechanism (electron injection in the conduction band or hole injection in the valence band) and show that they are interesting agents for the reduction of NAD+ and the regeneration of NADH.

New Zn-based catalysts are described that act as heterogenized or heterogeneous catalysts, with easy recovery and re-utilization with a limited or even zero Zn-leaching. For stabilizing in the heterogeneous form the catalytically active Zn centre, mixed oxides, ZIF-8 and Zn-tethered systems have been synthesized and found to sensibly reduce the leaching of Zn in solution with respect to ZnO, making possible their recovery and reuse. ZIF-8 can be used for long time of reaction, reaching high DEC yields (comparable or higher than those obtained with ZnO) without any significant loss of zinc

New catalytic systems based on ceria have been used in the direct carboxylation of ethanol. The catalytic behaviour of Al2O3 or Nb2O5 loaded ceria are compared, the latter showing a better performance. A morphological and structural study has been carried out on Nb2O5/CeO2 catalysts in order to explain their behaviour in catalysis. Pervaporation membranes have been used for water separation. The synthesis of diethylcarbonate-DEC has been carried out either in a liquid phase (ethanol) pressurized with CO2 or in supercritical conditions. A set-up has been developed that allows the production of quite pure DEC (>90%) with recycling of CO2 and ethanol.

Industrial utilization of CO2 is an important research area not only due to the potential contribution to the reduction of emissions into atmosphere, but also for saving carbon resources through the recycle of carbon. The use of solar energy in the conversion of CO2 appears to be a major challenge and opportunity for the future. A group of nanocrystalline zinc sulfide surface-modified with ruthenium(0) has been designed and characterized. Spectral, structural and electrochemical properties of powders have been determined. Photocatalytic properties of prepared materials were tested towards CO2 reduction to C1 compounds. Formic acid and carbon monoxide were found as the major reduction products proving solar to chemical energy conversion. The amount and ratio of products were influenced by the deposited ruthenium(0) co-catalyst and solvent polarity. The mechanism of HCOOH and CO formation, involves a transient CO2 •- radical generation. © 2015 Elsevier B.V. All rights reserved.

The invention relates to the synthesis of trimethylene carbonate by reaction of alcoholysis of urea with 1,3-propanediol in liquid phase catalyzed by a mixed metal oxide comprising Zn and La. The catalyst used in the process of the invention is an intimate mixture of Zinc oxide (ZnO) and Lanthanum oxide (La2O3) leading, according to the molar ratio La:Zn ranging from 0.01 to 1.5, to a new mixed metal oxide comprising a solid solution of Lanthanum or Zinc in Zinc oxide or Lanthanum oxide, respectively, or to a spinel like structure when the molar ratio La/Zn is equal to 1. The solid mixed catalyst La:Zn improves both yield and selectivity of the reaction and makes easier the further step of separating the compounds of the reaction medium with an improved recovering rate in trimethylene carbonate.

The present invention relates to a synthesis process of polyol carbonate, such as glycerol carbonate, from polyols such as glycerol, propylene glycol or ethylene glycol and urea conducted in using a solvent selective for polyols (glycerol) carbonates. Said process comprises reacting polyol with urea in the presence of a catalyst, extracting produced NH3 and in addition in the presence in the course of at least one step of the process of a selective solvent for polyol carbonate allowing to extract it from the reaction medium.