butyl esters
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Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8367
Author(s):  
Violeta Makareviciene ◽  
Migle Santaraite ◽  
Egle Sendzikiene

This article provides data on the environmental properties of biofuels obtained by the simultaneous extraction of oil from spoiled rapeseed and transesterification, with the addition of mineral diesel to the reaction mixture. The resulting reaction product contained 10% biodiesel: fatty acid methyl, ethyl, or butyl esters in mixtures with mineral diesel. The addition of biodiesel has been found to increase the rate of biodegradation of fuels. Such fuels are classified as partially biodegradable, according to the OECD classification. Life cycle analysis showed that the mixtures of biodiesel and mineral diesel have lower negative environmental impacts, compared to pure mineral diesel. The values of indicators such as abiotic depletion, acidification, global warming, ozone depletion, and human toxicity for these mixtures were 40–58% lower compared to the corresponding values for mineral diesel.


Author(s):  
Brian A. Callingham ◽  
M. Akram Khan ◽  
Anthony S. Milton ◽  
K. D. Rainsford

Abstract Background Non-steroidal anti-inflammatory drugs (NSAIDs) are a major cause of upper gastro-intestinal (GI) ulceration and bleeding as well as cardiovascular (CV) diseases (e.g., myocardial infarction and stroke). A feature common to both these adverse events is a variety of vascular reactions. One approach to overcome these side effects has been the development of nitric-oxide (NO)-donating NSAIDs. The NO is considered to overcome some of these vascular reactions caused by NSAIDs. Unfortunately, the NO-NSAIDs developed so far have not had the expected benefits compared with NSAIDs alone. Objectives Using in vitro preparations it is hoped to gain insight into the vascular and smooth muscle reactions induced by NO-NSAIDs compared with NSAIDs as a basis for improving the protective responses attributed to the NO-donating properties of these drugs. Methods A range of NO-NSAIDs was synthesized based on the esterification of NSAIDs with the nitro-butoxylate as a prototype of an NO-donor. These compounds, as well as NO-donor agents and NSAIDS, were examined for their possible effects on isolated segments of digital arteries of fallow deer, which provide a robust model for determining the effects of vasodilator and vasoconstrictor activities, in comparison with those of standard pharmacological agents. Results The NO-NSAIDs were found to antagonise the smooth muscle contractions produced by 5-hydroxytryptamine (serotonin, 5-HT). However, while almost all their parent NSAIDs had little or no effect, with the exception of the R-(−)-isomers of both ibuprofen and flurbiprofen, which caused vasodilatation, all the NO-NSAIDs tested antagonised the increase in tension produced by 5-HT. Conclusions R-(−)-ibuprofen and R-(−)-flurbiprofen, along with the nitro-butoxyl esters of the NSAIDs examined, produce relaxation of segments of deer digital artery smooth muscle in vitro. The evidence presented suggests that their mechanism involves the release of NO or its products.


2021 ◽  
pp. 174751982198996
Author(s):  
Huanhuan Luo ◽  
Yike Yang ◽  
Bobin Yang ◽  
Zhaojun Xu ◽  
Dawei Wang

Silver/manganese dioxide (Ag@MnO2) nanorods are synthesized and characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. It was discovered that Ag@MnO2 nanorods can realize hydrogen-borrowing reactions in high yields and are also effective for the synthesis of tert-butyl esters from aryl cyanides and tert-butyl hydroperoxide in a short period of time. Mechanistic experiments revealed that this catalytic system acts as a Lewis acid in hydrogen-borrowing reactions, while the synthesis of tert-butyl esters occurs through a radical pathway. This is the first report on the excellent catalytic activity of Ag@MnO2 nanorods as a catalyst.


2021 ◽  
Vol 15 (1) ◽  
pp. 105-117
Author(s):  
Serhiy Konovalov ◽  
◽  
Liubov Patrylak ◽  
Stepan Zubenko ◽  
Mykhaylo Okhrimenko ◽  
...  

Alkaline transesterification of sunflower oil by n-butanol and ethanol on alkoxide-containing dried solutions of potassium hydroxide has been carried out. Complex character of spontaneous dividing of butanolysis products, accompanying with formation of three different species of glycerol layers, was observed. One of the later was found to be high-alkaline pure glycerol. Bench motor testing of biodiesel/diesel blends demonstrated slightly better power performance of butyl esters comparing with ethyl esters and regular decrease of harmful emissions (CO2, CO, NOx, CH) while increasing biodiesel fraction in mixture.


2021 ◽  
Vol 6 (6) ◽  
pp. 1283-1287
Author(s):  
Jashuva V. P. Katuri ◽  
Kuppuswamy Nagarajan
Keyword(s):  

2021 ◽  
pp. 174751982098753
Author(s):  
Xiaofang Wu ◽  
Lei Zhou ◽  
Fangshao Li ◽  
Jing Xiao

A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.


Author(s):  
Bartłomiej Zieniuk ◽  
Małgorzata Wołoszynowska ◽  
Ewa Białecka-Florjańczyk ◽  
Agata Fabiszewska

Abstract Objective The aim of the study was to evaluate the possibility of using Y. lipolytica biomass as a whole-cell catalyst in the synthesis of lipophilic antioxidants, with the example of esterification of five phenolic acids with 1-butanol. Results Freeze-dried Y. lipolytica biomass was successfully applied as a biocatalyst in the synthesis of esters of phenylpropanoic acid derivatives with 75–98% conversion. However, in the case of phenylacetic acid derivatives, results below 10% were obtained. The biological activity of phenolic acid esters was strongly associated with their chemical structures. Butyl 3-(4-hydroxyphenyl)propanoate showed an IC50 value of 19 mg/ml (95 mM) and TEAC value of 0.427. Among the compounds tested, butyl esters of 3-(4-hydroxyphenyl)propanoic and 4-hydroxyphenylacetic acids exhibited the highest antifungal activity. Conclusions Lipophilization of phenolic acids achieved by enzymatic esterification creates prospects for using these compounds as food additives with antioxidant properties in lipid-rich food matrices.


Author(s):  
N. S. Kuzmina ◽  
S. V. Portnova ◽  
E. L. Krasnykh

Objectives. The study aims to identify the optimal choice of an effective catalyst for the esterification of malic acid to produce esters of high purity. Methods. To determine the qualitative and quantitative composition of reaction masses, the following analysis methods were used: mass-spectroscopy (using FinniganTrace DSQ device with NIST 2002, Xcalibur 1.31 Sp 5 database) and gas–liquid chromatography (using the Kristall 2000M software and hardware complex). Results. Esters of malic acid and butyl alcohol of normal structure were synthesized using the following catalysts: sulfuric, orthophosphoric, p-toluenesulfonic acid, Amberlyst 36 Dry, Amberlyst 36 Wet, KU-2-FPP, and KIF-T. The obtained products were analyzed by gas–liquid chromatography. The structure of the products was confirmed by mass spectrometry. Schemes for the formation of byproducts are proposed. The yields and purity of the malic acid butyl esters obtained using different catalysts were evaluated. The results show that the heterogeneous catalyst Amberlyst 36 Dry is optimal for obtaining a pure malic acid ester with a maximum yield. Conclusions. The results show that during the esterification of malic acid with butyl alcohol of normal structure, byproducts, such as esters of fumaric and maleic acids, are formed using different catalysts. An accumulation of byproducts occurs as a result of reactions of dehydration of malic acid or its ester. The results also show that the number of byproducts is almost independent of the catalyst, with the exception of sulfuric acid. The Amberlyst 36 Dry catalyst provides an optimal ratio between conversion and selectivity for malic acid dibutyl ester production. 


2020 ◽  
Vol 47 (6-7) ◽  
pp. 543-550 ◽  
Author(s):  
Yonghao Cui ◽  
Jianzhong He ◽  
Kun-Lin Yang ◽  
Kang Zhou
Keyword(s):  

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