Suchergebnisse

Supercritical carbon dioxide has been used as a green solvent due to their well-known potential in biomaterials impregnation. The versatility of this technique enables the loading of implants with Active Pharmaceutical Ingredients which present several benefits when compared with traditional techniques to impregnate active compounds. In this review, we have summarized the recent progress achieved in supercritical CO2assisted impregnation of active compounds and therapeutic deep eutectic systems for biomedical applications. ; The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number REGPOT-CT2012-316331-POLARIS and from the project "Novel smart and biomimetic materials for innovative regenerative medicine approaches" RL1 - ABMR - NORTE-01-0124-FEDER-000016) cofinanced by North Portugal Regional Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF). The authors would also like to acknowledge the financial support of the Associate Laboratory, Life and Health Sciences Research Institute / Biomaterials LA ICVS-3Bs (2015-2017). The authors would like also to thank to the financial support from the Portuguese Foundation for Science and Technology (FCT) for the fellowship grant of LAQV/BPD/037/2016, and to "Fundo Social Europeu"- FSE and "Programa Diferencial de Potencial Humano POPH". Alexandre Barros acknowledges his FCT PhD grant SFRH/BD/97203/2013. J.M.S acknowledges the project PTDC/CTM-BIO/4706/2014 for funding via an BPD grant. ...

The book focuses on new applications of green solvents (water, ionic liquids, supercritical carbon dioxide, terpenes). Keywords: Green Chemistry, Pollution Control, Hazardous Waste, Environmental Pollution, Green Solvents, Ionic Liquids, Supercritical Carbon Dioxide, Terpenes, Chemical Synthesis, Lipase-catalyzed Reactions, Organic Synthesis, Esterification, Gas Separation Membranes, Environment-friendly Products, Low Energy Requirement Processes, Alternatives to Hazardous Substances, Spiroheterocycles in Water, Sustainable Organic Synthesis, Chemical Industry, Pharmaceutical Industry, Paint Industry, Leather Industry.

AbstractThis paper provides a method of identifying land contaminated with chlorinated hydrocarbon solvents by sampling and analysing soil gas. Relationships are presented which enable levels of soil gas contamination to be related to levels of soil and groundwater pollution. Two case studies are presented. Soil gas surveying of an industrial site with severe groundwater pollution demonstrated that standards for contaminated land are insufficient to protect groundwater. Solvent levels in groundwater were one to two orders of magnitude higher than UK permitted concentrations in drinking water, whereas soil contamination values did not reach polluted levels. Surveying of a site occupied by a disused fire station showed significant differences in patterns of soil gas and groundwater pollution. This is explained by direct pollution of groundwater though the well at the site and/or possible flow of polluted groundwater to the site from adjacent areas.

The objective of this thesis was the development of an extraction process for the removal of multiple aromatics from several petrochemical streams by means of an ionic liquid. Due to environmental legislation, the demand of 'clean' fuels is increasing and most likely will increase even more towards fuels with almost zero content of certain aromatics, e.g. benzene and toluene. In particular, the concentration of benzene has to be reduced to = 0.1 wt-% in carburant fuels. Furthermore, the sulphur content of gasoline and diesel fuel has to be decreased to toluene > p-xylene > cumene > 1-hexene > n-hexane > n-heptane and for higher aromatics and cyclic aliphatics 9,10-dihydrophenanthrene > naphthalene > tetralin > decalin. Based on these screening results the ionic liquid [3-Mebupy][DCA] has been chosen for further evaluation due to the high capacity (Dbenzene,[3-Mebupy][DCA] = 0.60 [g/g]) and reasonable selectivity (¿[3-Mebupy][DCA],benzene/n-hexane = 35.3). Subsequent, the two ionic liquids [3-Mebupy][TCM] and [3-Mebupy][TCB] became available, which exhibit an even higher capacity and comparable or slightly lower selectivity (Dbenzene,[3-Mebupy][TCM] = 0.70 [g/g] and Dbenzene,[3-Mebupy][TCB] = 0.74 [g/g]; ¿[3-Mebupy][TCM],benzene/n-hexane = 34.8 and ¿[3-Mebupy][TCB],benzene/n-hexane = 27). Additionally, as petrochemical streams contain numerous components, including heterocycles, the affinity of heteroatoms towards ionic liquids has been studied in comparison to mono-aromatics. Therefore two model feeds containing sulphur aromatic components or nitrogen aromatics and toluene, tetralin and n-heptane have been investigated for the extraction with the same ionic liquids that showed to be promising for feeds containing only aromatic and aliphatic hydrocarbons. It was found that the sulphur and nitrogen containing hetero aromatics thiophene and dibenzothiophene and pyrrol, indole and carbazole are significantly better extracted than aromatic hydrocarbons. In one extraction step up to 80 % of the thiophene and up to 90 % of the dibenzothiophene can be removed while > 99 % of the nitrogen containing aromatics has been removed. Furthermore, the results for the model feeds are compared to real feed experiments in order to investigate the influence of a real petrochemical stream mixture compared to a model feed with a limited number of components. In all cases it was observed that the removal of the aromatic components from the real feed was less, due to competing influences of other components, but still promising. For the real feed experiments the ionic liquid [3-Mebupy][DCA] has been chosen. Whit a suitable candidate defined, the subsequent step is the development of an extraction process based on this ionic liquid. Therefore, a process design for the FCC gasoline model feed based on [3-Mebupy][DCA] comprising the main extraction column with the additional separation and solvent recovery units has been developed with Aspen plus together with an economical feasibility study of the process. The process comprises the main extraction column, a back extraction column for recovery of the ionic liquid that is withdrawn in the raffinate phase by entrainment, an extractive stripper in order to remove the co-extracted aliphatic components from the extract phase and a flash evaporator for separation of the aromatic product from the extraction solvent. Since [3-Mebupy][DCA] is hydrophilic, in contrary to the compounds present in the raffinate phase, the ionic liquid in the raffinate phase can be easily back-extracted by means of water. The results for investment and operational costs for the ionic liquid based process have been compared to a process using sulfolane as extraction solvent, since this is the most conventional solvent for aromatics extraction. It is shown that the investment costs for the ionic liquid based process are up to 42 % lower than for sulfolane and the annual costs for the [3-Mebupy][DCA] process are only 17.8 M€ compared to 32.6 M€ for a sulfolane process. This is due to the higher capacity of the ionic liquid which results in smaller process streams and therewith smaller equipment. The process design is based on the ternary diagrams that can be derived from the components present in the FCC gasoline and reformate model feeds and [3-Mebupy][DCA]. The ternary data have been determined experimentally and correlated with the NRTL model. The data regression for the two model feeds is in good agreement with the experimental data and the RMSD values are in general <0.0324. Additionally, the ternary diagrams for toluene/n-heptane with the three ionic liquids [BMIM][DCA], [BMIM][SCN] and [3-Mebupy][DCA] have been determined. The RMSD-values in this case are <0.0076. Furthermore, an experimental study on the scale-up of the FCC gasoline model feed and a real feed (LCCS) to a rotating disc contactor (RDC) pilot plant with the solvent [3-Mebupy][DCA] provided insight in mass transport and hydrodynamic effects, which is valuable information for an industrial process. Analogous to the LLE-measurements, it was shown that the extraction performance of the RDC column is higher for the model feed than for the real feed. From the FCC gasoline model feed 89 % benzene and 75 % toluene removal was observed while for the real feed 81 % benzene and 71 % toluene could be removed, respectively, with a solvent-to-feed ratio S/F = 4 and 800 rpm. This is due to competing effects of the multiple components in the real feed, which also hampers the mass transfer. Therefore, the mass transfer performance of RDC-column is also higher for the model feed than for the real feed. Besides, comparable hydrodynamic behaviour of the model and real feed has been observed. Since the densities and viscosities of both feeds are comparable, this explains the observed similar data in terms of Sauter means size diameter, hold-up and operational window. The conclusions that can be drawn from this work confirm that ionic liquids are potential solvents for the extraction of aromatic hydrocarbons as well as hetero aromatics containing sulphur and nitrogen. It has been reported that these components can be removed selectively from components as, e.g. olefins, aliphatics and cyclic aliphatics. Moreover, the results obtained with model feeds could be validated by means of real feed experiments on lab scale as well as pilot plant scale. Furthermore, from the conceptual process design based on [3-Mebupy][DCA] it is evident that an ionic liquid based extraction process can be energetically, and thus economically, more favourable than a sulfolane process. However, for the implementation of an ionic liquid extraction process on industrial scale further research has to be carried out in particular with view of the ionic liquid recovery and aromatics removal form the extract phase.

This article belongs to the Special Issue Applications of Deep Eutectic Solvents in Analytical Chemistry. ; The incessant generation of toxic waste and the growing concern over the environment have led the scientific community to delve into the search for more sustainable systems. In this regard, the application of deep eutectic solvents (DESs) has become one of the main strategies in green chemistry. These solvents have emerged as a promising alternative to conventional toxic solvents and even to the well-known ionic liquids. Their unique properties, components availability, and easy preparation, among others, have led to a new trend within the scientific community and industry, based on the use of these up-and-coming solvents not only in science but also in quotidian life. Among the areas that have benefited from the advantages of DESs is analytical chemistry, in which they have been largely used for sample preparation, including the extraction and determination of organic and inorganic compounds from environmental samples. The considerable number of applications developed in the last year in this field and the increasing generation of new data necessitate the continuous updating of the literature. This review pretends to compile the most relevant applications of DESs in environmental analysis and critically discuss them to provide a global vision about the advantages and drawbacks/limitations of these neoteric solvents in the area of environmental analysis. ; This work has been funded by the Spanish Ministry of Economy, Industry and Competitiveness (project AGL2017-89257-P). R.R.-R. and Á.S.-M. would like to thank the Canary Agency of Economy, Industry, Trade and Knowledge of the Government of the Canary Islands for the FPI fellowship (co-financed 85% from the European Social Funds). B.S.-R. would like to thank the Spanish Ministry of Science, Innovation and Universities for her "Juan de la Cierva" postdoctoral grant. ; Peer reviewed

Coccidiostats are drugs used against coccidiosis, a common disease among breeding animals. Their widespread application leads to the appearance of their residues in food, which is potentially harmful for human health and life. The European Union has established limits of concentrations of these drugs in premixtures and food. Nowadays, there are many methods for monitoring coccidiostats' presence in market products, but their frequent weakness is sample preparation. Solvent Front Position Extraction is a planar chromatography-based sample preparation method that allows for effective assay of samples with coccidiostats when coupled with LC-MS/MS. The purpose of this research was to find common conditions for the effective isolation of eight coccidiostats from biological sample components with both lower and higher retention than the substances of interest. The acquired results were used for effective isolation of monensin and salinomycin from the premixture samples and allowed for their quantitative determination. The application of a semi-automatic device for the development of chromatograms positively impacted the results, confirming the effectiveness of the method for determining coccidiostats in biological samples.

A popular narrative amongst European policymakers is that Eurozone members facing problems in the bond market are paying the price for past budgetary excess. Fiscal consolidation in these countries is seen as the principal remedy for the crisis. It is clear however that Ireland's problems derive mainly from a banking bust exacerbated by weaknesses in the design of Europe's monetary union and the policy response of both the Irish authorities and the European Central Bank. From the Euro's inception in 1999 up to 2007, both debt and deficit ratios in Ireland were comfortably within the Stability and Growth Pact ceilings. The gross debt ratio was only 25% of GDP at the end of 2007. The Stability and Growth Pact was the only macroprudential measure in place at Eurozone level, and Irish adherence reflected public finances flattered by a credit-fuelled property bubble. The banks experienced intense liquidity pressures in September 2008 and the Irish government provided a blanket liability guarantee. The banks were in reality badly insolvent, the bank guarantee has cost 40% of GDP and Ireland was forced from the bond market and into an EU/IMF programme just over two years later. There can be no presumption that it will emerge, and re-enter the bond market, on schedule at the end of 2013. This paper argues that the incomplete design of the currency union, with free capital movement and trans-border banking, but no centralised banking policy, contributed to the Irish debacle. The absence of bank resolution and any centralised system of liability insurance threw the burden of bank rescue on sovereigns. Countries in currency union are vulnerable to sovereign default, since they must borrow in what is, in effect, a foreign currency. Resort to official lenders enjoying seniority, combined with ECB insistence on sovereign repayment of bank senior bondholders, even in banks insolvent many times over, has undermined confidence in Irish sovereign debt. Closer fiscal union may prove necessary if the Eurozone is to survive. To avoid future sovereign debt crises, there is also a need for centralised bank supervision and resolution, as well as for a centralised system of liability insurance for banks. What happened in Ireland shows that sticking to purely fiscal rules is no guarantee of solvency for the sovereign in a currency union with inadequate mechanisms for the prevention and resolution of banking crises.