Dimethyl carbonate (DMC) is a versatile compound that represents an attractive eco-friendly alternative to both methyl halides (or dimethyl sulfate) and phosgene for methylation and carbonylation processes, respectively. In fact, the reactivity of DMC is tunable: at T = 90 degrees C, methoxycarbonylations take place, whereas at higher reaction temperatures, methylation reactions are observed with a variety of nucleophiles. In the particular case of substrates susceptible to multiple alkylations (e.g., CH(2)-active compounds and primary amines), DMC allows unprecedented selectivity toward mono-C- and mono-N-methylation reactions. Nowadays produced by a clean process, DMC possesses properties of nontoxicity and biodegradability which makes it a true green reagent to use in syntheses that prevent pollution at the source. Moreover, DMC-mediated methylations are catalytic reactions that use safe solids (alkaline carbonates or zeolites), thereby avoiding the formation of undesirable inorganic salts as byproducts. The reactivity of other carbonates is reported as well: higher homologues of DMC (i.e., diethyl and dibenzyl carbonate), are excellent mono-C- and mono-N-alkylating agents, whereas asymmetrical methyl alkyl carbonates (ROCO(2)Me with R > or = C(3)) undergo methylation processes with a chemoselectivity up to 99%.

Dimethyl carbonate (DMC) is an environmentally sustainable compound which can be used efficiently for the upgrading of several promising renewables including glycerol, triglycerides, fatty acids, polysaccharides, sugar-derived platform molecules and lignin-based phenolic compounds. This review showcases a thorough overview of the main reactions where DMC acts as a methylating and/or methoxycarbonylating agent for the transformation of small bio-based molecules as well as for the synthesis of biopolymers. All processes exemplify genuine green archetypes since they couple innocuous reactants of renewable origin with non-toxic DMC. Each section of the review provides a detailed overview on reaction conditions and scope of the investigated reactions, and discusses the rationale behind the choice of catalyst(s) and the proposed mechanisms. Criticism and comments have been put forward on the pros and cons of the described methods and their perspectives, as well as on those studies which still require follow-ups and more in-depth analyses

The fractal dimension of a macromolecular coil is used for the characterization of a polymeric melt structure. It is shown that the kinetics of oxygen consumption is defined by both the chemical constitution of a polymer and its structure. The quantitative analysis of the kinetical curves of the oxygen consumption in the thermooxidative degradation process was carried out in the framework of the fractal approach. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2378–2381, 2003

The methylating efficiency of dimethyl carbonate (DMC), dimethyl sulfate (DMS), methyl iodide (MeI), and methanol (MeOH) was assessed based on atom economy and mass index. These parameters were calculated for three model reactions: the O-methylation of phenol, the mono-C-methylation of phenylacetonitrile, and the mono-N-methylation of aniline. The analysis was carried out over a total of 33 different procedures selected from the literature. Methanol and, in particular, DMC yielded very favourable mass indexes (in the range 3-6) indicating a significant decrease of the overall flow of materials (reagents, catalysts, solvents, etc.), thereby providing safer greener catalytic reactions with no waste.

The waste-to-wealth concept aims to promote a future sustainable lifestyle where waste valorization is seen not only for its intrinsic benefits to the environment but also to develop new technologies, livelihoods and jobs.

There is the need for reproducible, simple, high-yielding synthetic protocols aimed at obtaining carbon dots (CDs) with controlled fluorescence, photothermal and photochemical behavior, surface properties, biocompatibility, tumor targeting ability, drug absorption biodistribution, and tumor uptake. This Letter describes a systematic study on the effect of glucose, fructose, and ascorbic acid as starting materials for the preparation of highly luminescent CDs, characterized by a blue emission. Their composition and morphology are investigated by titration of OH surface groups, spectroscopic techniques, and high-resolution transmission electron microscopy (HR-TEM), and their toxicity was tested toward HeLa cells. CDs made using fructose were toxic, while those made from glucose and ascorbic acid showed good biocompatibility. The reproducible and simple synthetic procedure yields luminescent biomass-derived CDs for combined cancer therapy and diagnostics. Their doxorubicin (DOX) drug uptake was measured by spectrofluorimetry, indicating a crucial role of the morphologies of the CDs in controlling DOX loading. The glucose derived CDs showed up to 28% w/w of DOX loading.

Fish biowaste is in the order of dozens of million tons per year, representing a resource of an extraordinary chemical richness, which is certainly worth valorising.

The photoreduction potential of a set of four different carbon dots (CDs) was investigated. The CDs were synthesized by using two different preparation methods hydrothermal and pyrolyticand two sets of reagentsneat citric acid and citric acid doped with diethylenetriamine. The hydrothermal syntheses yielded amorphous CDs, which were either nondoped (a-CDs) or nitrogen-doped (a-N-CDs), whereas the pyrolytic treatment afforded graphitic CDs, either non-doped (g-CDs) or nitrogen-doped (g-N-CDs). The morphology, structure, and optical properties of four different types of CDs revealed significant differences depending on the synthetic pathway. The photocatalytic activities of the CDs were investigated as such, that is, in the absence of any other redox mediators, on the model photoreduction reaction of methyl viologen. The observed photocatalytic reaction rates: a-N-CDs ≥ g-CDs > a-CDs ≥ g-N-CDs were correlated with the presence/absence of fluorophores, to the graphitic core, and to quenching interactions between the two. The results indicate that nitrogen doping reverses the photoredox reactivity between amorphous and graphitic CDs and that amorphous N-doped CDs are the most photoredox active, a yet unknown fact that demonstrates the tunable potential of CDs for ad hoc applications.