Temat: alcohols - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Comparison between surface and volumetric properties of short-chain alcohols and some classical surfactants
Autorzy:: Bielawska, Magdalena
Zdziennicka, Anna
Jańczuk, Bronisław
Tematy:: alcohols, surfactants, micelles, aggregates, CMC; Pokaż więcej
Wydawca:: Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Powiązania:: https://bibliotekanauki.pl/articles/764079.pdf Link otwiera się w nowym oknie
Opis:: Measurements of the dynamic surface tension of the aqueous solutions of methanol, ethanol, propanol, CTAB and SDDS at their given concentrations were made. From the obtained results and the literature data it was concluded that the adsorption of short-chain alcohols at the water-air interface is somewhat similar to that of classical surfactants. For that reason the relationship between the Gibbs standard free energy of adsorption of short-chain alcohols and classical surfactants at that interface was established. The correlation between the chemical potential of mixing of alcohols and surfactants was also analysed. This analysis concerned the critical aggregation concentration (CAC) of alcohols and the critical micelle concentration (CMC) of surfactants. The chemical potential of surfactant mixing was calculated from the literature CMC data for the homologous series of alkyl sulfates, alkyl sulfonates, alkyl ammonium chlorides, alkyl trimethylammonium bromides, and alkyl pyridinium bromides. The influence of the hydrophobic chain length of alcohol and surfactant molecules on the Gibbs standard free energy of their adsorption at the water-air interface and their chemical potential of mixing were considered. It appeared that there is a linear dependence between these thermodynamic functions and the number of carbon atoms increased by 1 in the hydrocarbon chains of these compounds. This confirms clearly our conclusion that the behaviour of short-chain alcohols and classical surfactants at the water-air interface and in the bulk phase of aqueous solutions is similar.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Frothers and gas dispersion: A review of the structure-property-function relationship
Autorzy:: Tan, Y. H.
Finch, J. A.
Tematy:: frothers
alcohols
polyglycols
frother structure
mechanisms; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109942.pdf Link otwiera się w nowym oknie
Opis:: Over the past 20 years quantitative measures of frother functions have been developed to try to replace such qualitative descriptors as “weak” and “strong”. One of these metrics is the critical coalescence concentration (CCC) that quantifies a frother’s ability to reduce bubble size; another is the concentration at minimum velocity (CMV) that quantifies a frother’s ability to reduce bubble rise velocity. The experimental procedure for the two measures is briefly outlined and the measures are shown to be related. Using CMV, based on more than 50 surfactants from the two main frother families, alcohols and polyglycols, the frother structure-property-function link is investigated. The structure variables were: in alcohols, alkyl chain length, and position of the methyl branch and hydroxyl group(s); and in polyglycols, alkyl chain length, and number of propylene oxide (PO) or ethylene oxide (EO) groups. On the argument that low CMV represents the desired outcome, the main findings are: the dominant effect of alkyl chain length in both alcohols and polyglycols; that for alcohols branched-chain isomers are superior to straight chain, with the best combination being OH at the terminus and the methyl branch as far away as possible; and for polyglycols, PO-based are superior to EO-based. Interpretation of these observations included the effect of structure on the following properties: surface activity, mass transfer rate, H-bonding, and molecule packing.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Detailed characterization of the substrate specificity of mouse wax synthase
Autorzy:: Miklaszewska, Magdalena
Kawiński, Adam
Banaś, Antoni
Tematy:: fatty alcohols
lipids
wax esters
acyl-CoA; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1039576.pdf Link otwiera się w nowym oknie
Opis:: Wax synthases are membrane-associated enzymes catalysing the esterification reaction between fatty acyl-CoA and a long chain fatty alcohol. In living organisms, wax esters function as storage materials or provide protection against harmful environmental influences. In industry, they are used as ingredients for the production of lubricants, pharmaceuticals, and cosmetics. Currently the biological sources of wax esters are limited to jojoba oil. In order to establish a large-scale production of desired wax esters in transgenic high-yielding oilseed plants, enzymes involved in wax esters synthesis from different biological resources should be characterized in detail taking into consideration their substrate specificity. Therefore, this study aims at determining the substrate specificity of one of such enzymes -; the mouse wax synthase. The gene encoding this enzyme was expressed heterologously in Saccharomyces cerevisiae. In the in vitro assays (using microsomal fraction from transgenic yeast), we evaluated the preferences of mouse wax synthase towards a set of combinations of 11 acyl-CoAs with 17 fatty alcohols. The highest activity was observed for 14:0-CoA, 12:0-CoA, and 16:0-CoA in combination with medium chain alcohols (up to 5.2, 3.4, and 3.3 nmol wax esters/min/mg microsomal protein, respectively). Unsaturated alcohols longer than 18°C were better utilized by the enzyme in comparison to the saturated ones. Combinations of all tested alcohols with 20:0-CoA, 22:1-CoA, or Ric-CoA were poorly utilized by the enzyme, and conjugated acyl-CoAs were not utilized at all. Apart from the wax synthase activity, mouse wax synthase also exhibited a very low acyl-CoA:diacylglycerol acyltransferase activity. However, it displayed neither acyl-CoA:monoacylglycerol acyltransferase, nor acyl-CoA:sterol acyltransferase activity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The reaction mechanism of chiral hydroxylation of p-OH and p-NH2 substituted compounds by ethylbenzene dehydrogenase
Autorzy:: Wójcik, Anna
Borowski, Tomasz
Tataruch, Mateusz
Witko, Małgorzata
Heider, Johann
Knack, Daniel
Dudzik, Agnieszka
Szaleniec, Maciej
Kozik, Bartłomiej
Opis:: Ethylbenzene dehydrogenase (EbDH; enzyme commission (EC) number: 1.17.99.2) is a unique biocatalyst that hydroxylates alkylaromatic and alkylheterocyclic compounds to (S)-secondary alcohols under anaerobic conditions. The enzyme exhibits a high promiscuity catalyzing oxidation of over 30 substrates, inter alia, para-substituted alkylphenols and alkylanilines. Secondary alcohols with OH and NH2 substituents in the aromatic ring are highly valuable synthons for many biologically active compounds in the fine chemical industry. EbDH hydroxylates most of the studied compounds highly enantioselectively, except for five substrates that harbour OH and NH2 groups in the para position, which exhibit a significant decrease in the percent enantiomeric excess (% ee). This phenomenon is inconsistent with the previously suggested enzyme mechanism, but it may be linked to a stabilization of the carbocation intermediate by deprotonation of the OH or NH2 substituent in the active site that yields a transient quinone (imine) ethide species. This would initiate an alternative reaction pathway involving the addition of a water molecule to a C=C double bond. This hypothesis was cross-validated by density functional theory (DFT) cluster modelling of the alternative reaction pathway with 4-ethylphenol, as well as by experimental assessment of the pH dependency of enantiomeric excesses. The results reported herein suggest that the alternative reaction pathway may significantly contribute to the overall reaction if the carbocation intermediates are stabilized by deprotonation.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 5.

Tytuł:: Propargylation of CoQ0 through the Redox Chain Reaction
Autorzy:: Stodulski, Maciej
Pawlowski, Robert
Mlynarski, Jacek
Wydawca:: American Chemical Society
Cytata wydawnicza:: J. Org. Chem. 2022, 87, 683−692. https://doi.org/10.1021/acs.joc.1c02685
Opis:: Foundation for Polish Science (TEAM/2017-4/38) Ministry of Science and Higher Education (Diamond Grant 0019/DIA/2018/47)
An efficient catalytic propargylation of CoQ0 is described by employing the cooperative effect of Sc(OTf)3 and Hantzsch ester. It is suggested to work through the redox chain reaction, which involves hydroquinone and dimeric propargylic moiety intermediates. A broad range of propargylic alcohols can be converted into the appropriate derivatives of CoQ0 containing triple bonds in good to excellent yields. The mechanism of the given transformation is also discussed.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 6.

Tytuł:: The analysis of the energy balance of the engine powered by diesel oil mixture with butanol
Autorzy:: Sitnik, L. J.
Andrych-Zalewska, M.
Tematy:: diesel engine
fuels
dense alcohols
energy balance; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/247462.pdf Link otwiera się w nowym oknie
Opis:: The development of motorisation involves using bigger amounts of fuels. These fuels are, until now, mainly petroleum. However, the fuels of bio origin must be used as well. It follows from the necessity of ensuring CO2 balance and from the fact that oil sources sooner or later will become exploited. Not less important is the fact that, principally, it is difficult to change the proportions of petrol and diesel oil extracted from crude oil, and the use of diesel oil increases proportionally faster than petrol. Therefore, it is necessary to use bio additives in diesel oil. One of such additives is dense alcohols. The aim of the present work is to determine the energy balance of diesel engine powered by diesel oil and butanol mixture. The work field includes making of energy balance of the engine in its characteristic points responsive 13 phase ESC test as well as determining on this basis the consolidated values concerning the differences in the engine energy balance. It has been proved, that powering the engine by mineral diesel oil with doped butanol (20% v/v) does not lead to essential differences in the energy balance of the engine- which does not mean, that the essential differences are absent in the particular characteristic points of the engine. It requires more detailed explanation (in the further research works) because losses in the combustion process do not show differences, but in the other balance components the differences are shown.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Influence of the kind and concentration of ethoxylated alcohols on the transport of citric acid through polymer inclusion membranes
Autorzy:: Dudek, M.
Przewoźna, M.
Gajewski, P.
Bogacki, M. B.
Tematy:: citric acid
polymer inclusion membranes
ethoxylated alcohols; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/778004.pdf Link otwiera się w nowym oknie
Opis:: Research into the influence of ethoxylated alcohols on the citric acid transport through polymer inclusion membranes (PIMs) has been carried out. This process may be used in the future as one of the methods of citric acid isolation. Ethoxylated alcohols, which were GENAPOL® X020, X060 and X150, served as both: plasticizer and carrier. The results showed that the maximum values of citric acid fl ux [mol/(m2.s)] were equal to: 1.02.10-4 (X020), 1.57.10-4 (X060) and 1.77.10-4 (X150). The obtained results allow proceeding further study on using the polymer inclusion membranes, as an alternative to traditional methods of citric acid separation, which are precipitation and extraction.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Theoretical Evaluation of Ultrasonic Velocity in Binary Liquid Mixtures of Alcohols [S] + Benzene
Autorzy:: Santhi, N.
Sabarathinam, P. L.
Madhumitha, J.
Alamelumangai, G.
Emayavaramban, M.
Tematy:: alcohols
benzene
sound
mixtures
NR
IMR
FLT
CFT; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/411951.pdf Link otwiera się w nowym oknie
Opis:: Ultrasonic velocities and densities of the binary liquid mixtures of benzene with 1-propanol, 2-propanol, 1-butanol, 2-butanol and 3-butanol at 303.15 to 318.15 K, over the entire composition range were measured. The theoretical values of ultrasonic velocity were evaluated using the Nomoto’s Relation (NR), Ideal Mixture Relation (IMR), Free Length Theory (FLT) and Collision Factor Theory (CFT). The validity of these relations and theories were tested by comparing the computed sound velocities with experimental values. Further, the molecular interaction parameter (á) was computed by using the experimental and the theoretical ultrasonic velocity values. The variation of this parameter with composition of the mixtures has been discussed in terms of molecular interaction in these mixtures.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Synthesis and evaluation of thermodynamic solubility of triazolo quinolone class derivatives in various solvents at 298.15-328.15 K
Autorzy:: Baluja, Shipra
Pithiya, Mona
Lava, Divyata
Tematy:: Triazolo quinolone
alcohols
ethyl acetate
solubility
thermodynamic parameters; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1031268.pdf Link otwiera się w nowym oknie
Opis:: The solubility of triazolo quinolone class derivatives in methanol, ethanol, n-propanol, n-butanol and ethyl acetate was measured using a gravimetrical method at temperature ranging from 298.15 K to 328.15 K. The results of these measurements were correlated with semi empirical equations. Some thermodynamic parameters such as dissolution enthalpy, Gibb’s free energy and entropy of mixing have also been calculated.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Asymmetric hydrosilylation of ketones catalyzed by zinc acetate with hindered pybox ligands
Autorzy:: Młynarski, Jacek
Łowicki, Daniel
Dudek, Agata
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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