Searching for green solvents Jessop, Philip G.
Green chemistry : an international journal and green chemistry resource : GC,
01/2011, Letnik:
13, Številka:
6
Journal Article
Recenzirano
Academic research in the area of green solvents is focused on neither the industries that use solvents most nor the types of solvents that the research community believes have the best hope of ...reducing solvent-related environmental damage. Those of us who are primarily motivated by a desire to reduce such damage would do well to look at the major uses of solvents, to determine the problems that currently make those applications less-than-green and focus our research efforts on potential solutions to those problems. As a contribution to such efforts, I present four grand challenges in the field of green solvents: finding a sufficient range of green solvents, recognizing whether a solvent is actually green, finding an easily-removable polar aprotic solvent and eliminating distillation.
Spożywanie alkoholu w trakcie ciąży jest zjawiskiem wysoce niepożądanym, często powodującym poronienia lub wiele nieprawidłowości rozwojowych dziecka. Spektrum Płodowych Zaburzeń Alkoholowych, tzw. ...FASD (ang. Fetal Alcohol Spectrum Disorder) określa zaburzenia fizyczne i psychiczne wynikające z wpływu alkoholu na zdrowie oraz zaburzenia behawioralne dziecka, które zazwyczaj są wtórne do zmian zachodzących w ośrodkowym układzie nerwowym, wywołanych alkoholowym zatruciem płodu w trakcie ciąży. Zmiany te są zazwyczaj nieodwracalne i uwidaczniają się w trakcie całego życia dziecka dotkniętego FASD, ale dzięki odpowiednim terapiom istnieje możliwość zminimalizowania objawów tych zaburzeń. Ich charakter i ciężkość zależą od kilku czynników, między innymi od czasu ekspozycji na alkohol oraz stanu zdrowia kobiety ciężarnej. Wśród klinicznych cech FASD wyróżnia się anomalie w obrębie twarzoczaszki, zaburzenia ośrodkowego układu nerwowego oraz opóźnienie wzrostu. Zmiany strukturalne indukowane alkoholem obejmują anomalie w układzie sercowo-naczyniowym, szkieletowym, nerkowo-moczowodowym, a także w narządach wzroku i słuchu. Ważną rolę odgrywa czas postawienia wstępnej diagnozy, bowiem umożliwia on wprowadzenie odpowiedniej terapii dla dziecka z FASD oraz wprowadzenie odpowiedniej edukacji rodziców i rodziny chorego dziecka. Istnieje możliwość zminimalizowania objawów i zaburzeń wynikających ze Spektrum Płodowych Zaburzeń Alkoholowych, do stopnia umożliwiającego prawidłowe funkcjonowanie dziecka i jego rodziny.
We report on a wearable tear bioelectronic platform, integrating a microfluidic electrochemical detector into an eyeglasses nose-bridge pad, for non-invasive monitoring of key tear biomarkers. The ...alcohol-oxidase (AOx) biosensing fluidic system allowed real-time tear collection and direct alcohol measurements in stimulated tears, leading to the first wearable platform for tear alcohol monitoring. Placed outside the eye region this fully wearable tear-sensing platform addresses drawbacks of sensor systems involving direct contact with the eye as the contact lenses platform. Integrating the wireless electronic circuitry into the eyeglasses frame thus yielded a fully portable, convenient-to-use fashionable sensing device. The tear alcohol sensing concept was demonstrated for monitoring of alcohol intake in human subjects over multiple drinking courses, displaying good correlation to parallel BAC measurements. We also demonstrate for the first time the ability to monitor tear glucose outside the eye and the utility of wearable devices for monitoring vitamin nutrients in connection to enzymatic flow detector and rapid voltammetric scanning, respectively. These developments pave the way to build an effective eyeglasses system capable of chemical tear analysis.
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•Wearable fluidic tears biosensor and wireless circuitry integrated into eyeglasses for non-invasive biomarker monitoring.•Wearable tear sensing platform placed outside the eye region mitigates drawbacks of systems requiring direct eye contact.•Real-time collection and direct measurements of stimulated tears allow the first wearable tear alcohol monitoring platform.
Diesel engines are the main source of rapidly-growing energy consumption worldwide. Diesel consumption is responsible for serious air pollution, which includes nitrogen oxides (NOx), hydrocarbon ...(HC), carbon monoxide (CO) emissions and some particulate matter (PM) discharged from the combustion chamber. In the past few decades, alternative fuels, such as alcohol, biodiesel, natural gas, and Di Methyl Ether (DME), have been used in diesel engines to reduce energy costs and environmental pollution. As a result of alternative fuels directives, an increasing number of diesel engines have adapted dual fuel blends, and an enormous amount of research is focused on new and inadequately studied combustion and emission profiles. Compared to conventional diesel fuel, the application of dual fuels would add new parameters to combustion and emission profiles for diesel vehicles worldwide. This review aims to reveal (1) Known and anticipated combustion characteristics and emissions products from dual fuels. (2) Toxic properties and the expected influence on engine performance. (3) Identifying promising alternative fuels for emissions control in compression combustion engines. The results presented herein will show a significant reduction of regular gas and PM emissions by the use of alcohol/diesel dual fuel, while unregulated emissions such as methanol, ethanol, acetaldehyde, formaldehyde, ketone, have increased compared to those from diesel fuel. PM emissions decreased significantly with the increase of alternative fuels, such as alcohols, natural gas, biodiesel and DME, while regular gaseous emissions varied depending on the type alternative fuel and the engine conditions. As one new and cleaner substitute for diesel engines, DME operation has a longer injection delay, lower maximum cylinder pressure, a lower ratio of pressure rise, and shorter ignition delay in comparison with diesel operation--the opposite of alcohol/diesel and dual fuels. This review evaluates the effects of some alternative fuels (alcohol, biodiesel, natural gas and Di Methyl Ether (DME)) on combustion characteristics and emission products from diesel engines to meet future emission regulations using alternative fuel.
•Vinegar is liquid product from alcoholic and acetous fermentation of suitable food.•Vinegar varieties: black vinegar, rice vinegar, balsamic vinegar, white wine vinegar.•Vinegar contains various ...bioactives: polyphenols, micronutrients and antioxidants.•Bioactivities of vinegars include antimicrobial, antioxidative and antidiabetic.
Vinegars are liquid products produced from the alcoholic and subsequent acetous fermentation of carbohydrate sources. They have been used as remedies in many cultures and have been reported to provide beneficial health effects when consumed regularly. Such benefits are due to various types of polyphenols, micronutrients and other bioactive compounds found in vinegars that contribute to their pharmacological effects, among them, antimicrobial, antidiabetic, antioxidative, antiobesity and antihypertensive effects. There are many types of vinegars worldwide, including black vinegar, rice vinegar, balsamic vinegar and white wine vinegar. All these vinegars are produced using different raw materials, yeast strains and fermentation procedures, thus giving them their own unique tastes and flavours. The main volatile compound in vinegar is acetic acid, which gives vinegar its strong, sour aroma and flavour. Other volatile compounds present in vinegars are mainly alcohols, acids, esters, aldehydes and ketones. The diversity of vinegars allows extensive applications in food.
I denne artikkelen undersøker vi hvilken betydning alkohol og alkoholhåndtering har for unge kvinner og menn med krysskulturell oppvekst. Vi anvender interseksjonalitet som perspektiv for å belyse ...hvordan ulike sosiale kategorier kan påvirke unges livsbetingelser og opplevelser av tilhørighet. Artikkelen bygger på kvalitative intervjuer med 13 unge voksne, som forteller om sine erfaringer med krysskulturell oppvekst. Våre analyser viser at alkohol og alkoholhåndtering har en sentral betydning i deres opplevelser og navigering av tilhørighet til majoritets- og minoritetsmiljøer. Som unge, religiøse kvinner og menn opplever de at alkoholkonsum og festing fungerer som markører for det å være ung og norsk, og at alkoholbruk er en betingelse for å bli en del av det norske majoritetsfellesskapet. Fra egne familier og minoritetsmiljøer opplever deltakerne derimot en forventning om avholdenhet og at de avstår fra fellesskap der det brukes alkohol. De motstridende forventningene vanskeliggjør navigering av tilhørighet til både majoritets- og minoritetsmiljøer. Artikkelen bidrar til å gi en økt forståelse av hvordan alkoholbruk er forbundet med hierarkiserende konstruksjoner av norskhet og fremmedhet, og inndelinger i «oss» og «dem».
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•Overview of ketonization of carboxylic acids, aldehydes, alcohols, and esters.•Acid, aldehyde, alcohol, and ester ketonization pathways are closely related.•Ketonization depends on ...catalyst redox and acid-base properties and pretreatment.•Additional kinetic, spectroscopic, and computational studies further required.
The ketonization of various renewable biomass-derived oxygenated feedstocks such as carboxylic acids, aldehydes, alcohols, and esters is presented. As most previous ketonization reports focused on carboxylic acids, this overview extends the scope to homo-, cross-, and cyclo-ketonization of not only carboxylic acids (e.g., acetic, propionic, butyric, lactic, valeric, levulinic, dicarboxylic, and higher acids), but also of lesser reported aldehydes (e.g., acetaldehyde, propionaldehyde, and butyraldehyde), alcohols (e.g., ethanol, propanol, butanol, diols, and higher alcohols), and esters (e.g., small, intermediate, and large alkanoate chain length esters) aiming at obtaining more stable products, biofuels, and high-value chemicals. Ketonization of carboxylic acids (e.g., catalysts, mechanisms) is presented to provide the basis for understanding the ketonization of aldehydes, alcohols, and esters over metal oxides including ceria, titania, and zirconia, which have been the most active and studied catalysts for this reaction. Whenever possible, examples of ketonization of biomass-derived oxygenated compounds are presented to highlight the utility of the reaction and its practical application. As biomass product streams can contain a large number of different oxygenated compounds (e.g., more than 350 compounds in bio-oil), ketonization examples in the presence of more than one oxygenated molecule have also been considered.
Due to rapid industrialisation and use of advanced technologies there has been increase in the consumption of fossil fuels, especially petroleum. Increasing needs are reciprocally proportionate to ...diminishing reserves of coal and petroleum. So, the exaggerated to be fulfilled and to curb the problem of increasing fuel prices; researchers are putting their efforts to produce an alternative fuel from replenish able resources on large scale. Biodiesel itself is proving to be a reliable and competent competitor to non-renewable petroleum which is being produced from commonly accustomed plants for instancerapeseed, soybean, sunflower and palm etc. But, complication is that it becomes a problem for in-availability of these oils for foods. Now non-edible raw materials oils such as Pongamia, Jatropha, Mahua, Moringa seed oil etc. have been used to raise the standard of these oils and being produced to complete the level of petroleum and be proven as the best resources for biodiesel production in all approaches both technically and economically. In this paper emphasis has been laid down to review the impact of higher alcohols, use of different raw materials for biodiesel preparation and effect of their composition on Oxidation Stability and Cold Flow properties. Moreover, various production technologies used to produce biodiesel were also reviewed and comparison was done among them for better yield. Further, an attempt has been made to investigate the effect of higher alcohols on biodiesel yield and its properties. The study concludes that oxidation stability depends upon unsaturation mainly linoleic acid and lenolenic acid. Moringa olifera, Moroccan frying oil, Schleichera oleosa L. oil, Moringa peregeria are prospective oils as per oxidative stability characteristics. In contrast to it, cold flow properties depend upon saturation and suggests that having more saturated fatty acids result in poor cold flow properties.
Given the widespread importance of amides in biochemical and chemical systems, an efficient synthesis that avoids wasteful use of stoichiometric coupling reagents or corrosive acidic and basic media ...is highly desirable. We report a reaction in which primary amines are directly acylated by equimolar amounts of alcohols to produce amides and molecular hydrogen (the only products) in high yields and high turnover numbers. This reaction is catalyzed by a ruthenium complex based on a dearomatized PNN-type ligand where PNN is 2-(di-tert-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine, and no base or acid promoters are required. Use of primary diamines in the reaction leads to bis-amides, whereas with a mixed primary-secondary amine substrate, chemoselective acylation of the primary amine group takes place. The proposed mechanism involves dehydrogenation of hemiaminal intermediates formed by the reaction of an aldehyde intermediate with the amine.
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