79 research outputs found
Green Chemistry Approach to the Synthesis of Biscoumarins from 4-Hydroxycoumarin
Numerous biological and pharmacological properties of coumarins have designated them as significant synthetic target in many fields. Biscoumarins are considered as an important class of coumarin derivatives that show remarkable pharmacological properties. Therefore, development of the efficient new methods for their synthesis, based on green methodology, would be of a great importance in medicinal and pharmaceutical chemistry.
In this work, the ultrasound and microwave assisted synthesis of biscoumarins, starting from corresponding aldehydes and 4-hydroxycoumarin is reported. Molecular iodine was used as an efficient and inexpensive catalyst for a simple synthesis, to obtain excellent yields using ethanol as a solvent. It was found that 10 % (n/n) of molecular iodine catalyzes biscoumarin synthesis in high yields (80ā94 %) and in short reaction times, using both ultrasound, as well as microwave promoted conditions. Furthermore, when those two methods are compared, ultrasound promoted reactions were proven to be more suitable for this kind of reaction.
This work is licensed under a Creative Commons Attribution 4.0 International License
Deep Eutectic Solvents in the Production of Biopolymer-Based Materials
Deep eutectic solvents (DESs) are multipurpose media for polysaccharide treatment. Thus, the DESs are also used as a plasticizers in preparation of thermoplastic films from natural polymers. Since attempts are being made to reduce the production of petroleum-based polymer materials, DESs are a good alternative in the production of biopolymers. DESs have desirable properties such as low costs, biodegradability and non- or low toxicity. This review summarizes research that are dealing with preparation of biopolymer-based materials with DESs in the role of plasticizer.
This work is licensed under a Creative Commons Attribution 4.0 International License
Screening of Natural Deep Eutectic Solvents for Green Synthesis of 2-methyl-3-substituted Quinazolinones and Microwave-Assisted Synthesis of 3-aryl Quinazolinones in Ethanol
In this study, two fast and efficient protocols for green synthesis of 3-substituted quinazolinones were perfomed. A synthesis of
2-methyl-3-substituted quinazolinones was performed in natural deep eutectic solvents, while 3-aryl quinazolinones were obtained by using microwave assisted synthesis. Benzoxazinone, which was used as an intermediate in the synthesis of 2-methyl-3-substituted quinazolinones, was prepared conventionally from anthranilic acid and acetic anhydride. In order to find the most appropriate synthetic path, twenty natural deep eutectic solvents were applied as a solvent in these syntheses. Choline chloride:urea (1 : 2) was found to be the most efficient solvent and was further used in the synthesis of 2-methyl quinazolinone derivatives (2ā12). 3-Aryl quinazolinones (13ā17), on the other hand, were synthesized in one-pot microwave-assisted reaction of anthranilic acid, different amines and trimethyl orthoformate. All compounds were synthesized in good to excellent yields, characterized by LC-MS/MS spectrometry and 1H- and 13C-NMR spectroscopy.
This work is licensed under a Creative Commons Attribution 4.0 International License
RISKS OF CSRIN BUSINESS AND BUSINESS ETHICAL RISKS
Suvremeno poslovanje oznaÄava velika konkurencija i stalne promjene, potroÅ”aÄi koji su svjesni svojih prava i osjetljivi na zaÅ”titu okoliÅ”a te sve veÄi rizik u poslovanju. Moderni poslovni svijet je sve složeniji i kompliciraniji. Ljudi su nepovjerljivi zbog raznih skandala u poslovnim krugovima poput korupcije, krÅ”enja prava radnika i uniÅ”tavanja okoliÅ”a. PoduzeÄa se moraju suoÄiti s rizicima, etiÄkim dilemama i dokazivanjem korisnog uÄinka na druÅ”tveno odgovorno poslovanje.Ovim radom prikazat Äe se etiÄki rizici te rizici druÅ”tveno odgovornog poslovanja, naÄin na koji se poduzeÄa trebaju nositi s tim rizicima te kako njima upravljati.Business management nowadays is very competitive and there are continuous changes on the market and people are aware and conscious of customer rights and very sensitive of environmental protection, so risks in business management are very high. Modern business management is getting more complicated and customers are distrustful because of various scandals in business circles like corruption, breaking workers rights and destroying the environment. Companies have to deal with risks, ethical dillemas and proving their useful influence with corporate social responsibility.This thesis aims to show ethical risks, risks of corporate social responsibility and methods of dealing with that type of risks and how to manage them
Povezanost perfekcionizma sa samopoŔtovanjem i zadovoljstvom kvalitetom života
Not many researches have been investigating the relationship of perfectionism with adaptive aspects of human behaviour. For that reason, aim of this study was to investigate the relationship of positive and negative perfectionism with adaptive measures of self-esteem and satisfaction with the quality of life, and to find out the differences between adaptive perfectionists, nonadaptive perfectionists and nonperfectionists in these measures. Instruments used are Positive and Negative Perfectionism Scale, Rosenberg Self-Esteem Scale and one item question about how a person is satisfied with his/her life as a whole. The results showed positive relationship of positive perfectionism with self-esteem and assessment of satisfaction with life, and negative relationship of negative perfectionism with these variables. Further more, the results indicated that nonadaptive perfectionists had lower levels of self-esteem than adaptive perfectionists and nonperfectionists, while there was no such difference between these two groups. Results also showed no differences between these groups of perfectionists and nonperfectionists in the assessment of satisfaction with life variable.Malen broj istraživanja se bavio povezanoÄu perfekcionizma s adaptivnim aspektima Äovjekovog ponaÅ”anja i doživljavanja. Stoga je cilj ovog rada bio istražiti povezanost pozitivnog i negativnog perfekcionizma s adaptivnim mjerama samopoÅ”tovanja i zadovoljstva kvalitetom života, te utvrditi razlike izmeÄu adaptivnih i neadaptivnih perfekcionista te neperfekcionista u navedenim mjerama. KoriÅ”teni mjerni instrumenti su Ljestvica pozitivnog i negativnog perfekcionizma, Rosenbergova ljestvica osobnog samopoÅ”tovanja te jedna Äestica koja postavlja pitanje koliko je osoba, u cjelini gledajuÄi, zadovoljna kvalitetom vlastitog života. Rezultati su ukazali na pozitivnu povezanost pozitivnog perfekcionizma sa samopoÅ”tovanjem i procjenom zadovoljstva kvalitetom života, te negativnu povezanost negativnog perfekcionizma s navedenim varijablama. Pokazalo se i da neadaptivni perfekcionisti imaju znaÄajno nižu razinu samopoÅ”tovanja u odnosu na adaptivne perfekcioniste i neperfekcioniste, dok izmeÄu tih dviju grupa nije bilo razlike. MeÄutim, nisu dobivene nikakve razlike izmeÄu adaptivnih, neadaptivnih perfekcionista i neperfekcionista u procjeni zadovoljstva kvalitetom života
Coumarin in grounded cinnamon and teas containing cinnamon - extraction and determination by HPLC method
Cinnamon, a commonly used spice as well as a part of many commodities, such as breakfast cereals, teas and bakery products, represents an important part of the diet. Cinnamon, among many bioactive components, contains an important active compound coumarin. Numerous studies have shown that coumarin has a beneficial health effect on the body in optimal consumption, while increased long-term consumption can lead to adverse health effects. In this paper, the amount of coumarin in ten different products found on the Croatian market, including ground spices and teas, was analyzed. In addition, different extraction parameters were analyzed in order to find the best method of extraction of coumarin from cinnamon and products containing cinnamon
Various techniques for phenolic removal from olive mill wastewater
As the world\u27s population increases, so does the amount of wastewater generated during agricultural activities. Inadequate wastewater management can be the cause of sea and river pollution. However, wastewater can be a potential source of biologically active components that can be obtained via physicochemical, biological, thermochemical or combined treatments. Olive mill wastewater is produced in huge quantities around the world during the production of olive oil. This waste is harmful to the ecological system due to the high content of phenolic components that can be recovered by different methods whereby this waste also gains economic value. This review describes several methods that can be used in phenol removal or isolation from olive mill wastewater
Green extraction techniques of bioactive components from cocoa shell
The aim of this study was to demonstrate that certain types of extraction techniques can give extracts with various bioactive components in different concentrations. Four green extraction techniques were used in this study: supercritical CO2 extraction, ultrasound-assisted extraction, cold atmospheric plasma extraction and extraction using deep eutectic solvents. Those modern techniques gave better yields of bioactive components and showed better antioxidant activity of obtained extracts than classical Soxhlet extraction. The bioactive components in obtained extracts were quantified by High Performance Liquid Chromatography. Supercritical CO2 extraction gave the highest yields for theobromine content, while ultrasound-assisted extraction with 50% aqueous ethanol solution gave the highest caffeine yields during 30 min of extraction, 35 Hz and 60 Ā°C. The extraction with deep eutectic solvent mixture of choline chloride: oxalic acid and 50% pure H2O at room temperature during 180 min of extraction time gave the highest total phenol content while the same mixture under the same conditions, but during longer extraction time (360 min), gave the highest antioxidant activity.
Cocoa shell (CS), due to its nutritional value and bioactive components, has a potential to become a desirable raw material in a large spectrum of functional and pharmaceutical products
ULTRASOUND-ASSISTED EXTRACTION OF ACTIVE COMPOUNDS FROM COCOA BEAN SHELL
In today\u27s overcrowded world with declining food supplies and the constant struggle against waste accumulation, scientists are increasingly trying to discover new ways to solve these problems. Like many industries, the food industry generates, disposes and accumulates waste thus creating an environmental and economic problem. In this study the one of the green extraction technologies, ultrasound-assisted extraction (UAE), for isolation of bioactive compounds from cocoa bean shell (CBS), a by-product in the chocolate production, was applied. Different temperature (40, 60, 80 Ā°C), extraction time (30, 60, 90 minutes), liquid/solid ratio (10, 30, 50 mL/g) and ultrasound power (30, 50, 70 %) were used to obtain the cocoa bean shell extracts. Six active compounds were detected in the extracts by high performance liquid chromatography with a diode array detector as follows: theobromine (2.077-5.916 mg/g), gallic acid (0.110-1.407 mg/g), caffeine (0.276-0.785 mg/g), catechin
(0.033-0.457 mg/g), while the highest obtained concentrations for epicatechin and caffeic acid were 0.100 and 0.527 mg/g of CBS. The highest total phenolic content (TPC) and % scavenging activity measured were 132.897 mgGAE/gextr. and 86.377%. From all investigated parameters, liquid/solid ratio had the greatest influence on the concentrations of obtained compounds. Study proved how UAE is an efficient method for the extraction of bioactive compounds from food by-product - CBS. It should also be emphasized that such application could find the purpose at the industrial level for the discarded waste that still contains valuable compounds, while the enriched extracts could be further used as raw material in other processes
ULTRASOUND-ASSISTED EXTRACTION OF ACTIVE COMPOUNDS FROM COCOA BEAN SHELL
In today\u27s overcrowded world with declining food supplies and the constant struggle against waste accumulation, scientists are increasingly trying to discover new ways to solve these problems. Like many industries, the food industry generates, disposes and accumulates waste thus creating an environmental and economic problem. In this study the one of the green extraction technologies, ultrasound-assisted extraction (UAE), for isolation of bioactive compounds from cocoa bean shell (CBS), a by-product in the chocolate production, was applied. Different temperature (40, 60, 80 Ā°C), extraction time (30, 60, 90 minutes), liquid/solid ratio (10, 30, 50 mL/g) and ultrasound power (30, 50, 70 %) were used to obtain the cocoa bean shell extracts. Six active compounds were detected in the extracts by high performance liquid chromatography with a diode array detector as follows: theobromine (2.077-5.916 mg/g), gallic acid (0.110-1.407 mg/g), caffeine (0.276-0.785 mg/g), catechin
(0.033-0.457 mg/g), while the highest obtained concentrations for epicatechin and caffeic acid were 0.100 and 0.527 mg/g of CBS. The highest total phenolic content (TPC) and % scavenging activity measured were 132.897 mgGAE/gextr. and 86.377%. From all investigated parameters, liquid/solid ratio had the greatest influence on the concentrations of obtained compounds. Study proved how UAE is an efficient method for the extraction of bioactive compounds from food by-product - CBS. It should also be emphasized that such application could find the purpose at the industrial level for the discarded waste that still contains valuable compounds, while the enriched extracts could be further used as raw material in other processes
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