Wyniki wyszukiwania - Biblioteka Nauki

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Factors Affecting the Phase Inversion Process of Alkyl polyglycol ether C16-18/Fatty Alcohol/Oil/Water System

100%

Zhang W. , Cui D. , Zhang Q. , Zhang D. , Zhu G.

Polish Journal of Chemical Technology

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2024

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tom Vol. 26, nr 4

64--71

EN

The change of spontaneous curvature of nonionic surfactants is related to temperature. The phase inversion of the emulsion system is induced by temperature change, which is called phase inversion temperature method. Experiments were carried out in which Ceteareth-12 (Alkyl polyglycol ether C16-18) and Ceteareth-20 (Alkyl polyglycol ether C16-18) were used as hydrophilic emulsifiers and fatty alcohol as lipophilic emulsifiers. It was found that the increase of HLB value of hydrophilic emulsifier, the decrease of fatty alcohol content or the increase of carbon atom number of fatty alcohol led to the increase of phase inversion temperature of the system. The experimental results also showed that when the hydrophilicity of emulsifier system was enhanced, the second phase inversion would be more obvious. The phase inversion temperature of ester oils is generally higher than that of alkane oils.

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Biochemical characteristics of AtFAR2, a fatty acid reductase from Arabidopsis thaliana that reduces fatty acyl-CoA and -ACP substrates into fatty alcohols

88%

Doan T. , Carlsson A. , Stymne S. , Hofvander P.

Acta Biochimica Polonica

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2016

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tom 63

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nr 3

565-570

EN

Fatty alcohols and derivatives are important for proper deposition of a functional pollen wall. Mutations in specific genes encoding fatty acid reductases (FAR) responsible for fatty alcohol production cause abnormal development of pollen. A disrupted AtFAR2 (MS2) gene in Arabidopsis thaliana results in pollen developing an abnormal exine layer and a reduced fertility phenotype. AtFAR2 has been shown to be targeted to chloroplasts and in a purified form to be specific for acyl-ACP substrates. Here, we present data on the in vitro and in planta characterizations of AtFAR2 from A. thaliana and show that this enzyme has the ability to use both, C16:0-ACP and C16:0-CoA, as substrates to produce C16:0-alcohol. Our results further show that AtFAR2 is highly similar in properties and substrate specificity to AtFAR6 for which in vitro data has been published, and which is also a chloroplast localized enzyme. This suggests that although AtFAR2 is the major enzyme responsible for exine layer functionality, AtFAR6 might provide functional redundancy to AtFAR2.

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Detailed characterization of the substrate specificity of mouse wax synthase

75%

Miklaszewska M. , Kawinski A. , Banas A.

Acta Biochimica Polonica

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2013

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tom 60

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nr 2

EN

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.

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Płuczka wiertnicza z dodatkiem pochodnych alkoholi tłuszczowych

63%

Zima G.

Nafta-Gaz

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2020

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tom R. 76, nr 3

162--174

PL

W artykule przedstawiono wyniki badań nad opracowaniem płuczek wiertniczych zawierających pochodne alkoholi tłuszczowych, które zapewnią uzyskanie ich optymalnych właściwości inhibitacyjnych w warunkach otworowych. W składach płuczek zostały zastosowane alkoksylowe pochodne alkoholi tłuszczowych, które są środkami niejonowymi i ich inhibitacyjne właściwości zostały potwierdzone we wcześniej przeprowadzonych badaniach. Płuczki o opracowanych składach zostały poddane badaniom w warunkach HPHT oraz obecności skażeń chemicznych i wzrastającej zawartości fazy stałej. Ze względu na możliwość zastosowania płuczek zawierających nowe rodzaje inhibitorów do dowiercania złóż, przeprowadzono również badania ich wpływu na uszkodzenie przepuszczalności skał zbiornikowych. Zastosowanie nowego rodzaju inhibitora wymagało opracowania metodyki kontrolowania jego zawartości w płuczce oraz metodyki obróbki płuczki w czasie wiercenia. Dotychczas stosowane tego typu inhibitory to tzw. poliglikole, będące polimerami tlenku etylenu lub kopolimerami tlenku etylenu i tlenku propylenu różniące się masą cząsteczkową. Głównym badaniem potwierdzającym inhibitacyjne właściwości płuczek jest badanie dyspersji skały ilastej, standardowo przeprowadzane w warunkach otoczenia. W niniejszym artykule opisano badania dyspersji w warunkach podwyższonej temperatury celem potwierdzenia właściwości inhibitacyjnych badanych środków w warunkach zbliżonych do otworowych. Badania dyspersji powiązano dodatkowo z pomiarami pęcznienia, czyli przyrostu objętościowego skały ilastej w środowisku płuczek wiertniczych. Przeprowadzono również badania płuczek zawierających nowe rodzaje poliglikoli w warunkach otworopodobnych: wykonano badania odporności tych płuczek na skażenie jonami metali dwuwartościowych (Ca2+ i Mg2+), skażenie fazą stałą (zmielonym łupkiem mioceńskim imitującym zwierciny) oraz działanie podwyższonej temperatury. Przedstawiona w artykule tematyka jest wynikiem niesłabnącego zainteresowania ze strony przemysłu stosowaniem płuczek z dodatkiem tego typu inhibitorów. Środki te posiadają podobne właściwości do dotychczas stosowanych poliglikoli, ale wykazują większą efektywność w warunkach otworowych.

EN

The article presents the results of research on the development of drilling muds containing derivatives of fatty alcohols, which will ensure that their optimal inhibitory properties in borehole conditions are achieved. In the mud compositions, alkoxy derivatives of fatty alcohols were used, which are non-ionic agents and their inhibitory properties have been confirmed in earlier studies. Drilling fluids were tested under HPHT conditions as well as under conditions of chemical contamination and increasing solids content. Due to the possibility of using muds containing new types of inhibitors to drill-in, studies on their effect on damage to reservoir rock permeability were also conducted. The use of a new type of inhibitor required the development of a methodology for controlling its content in the mud and a method for treating the mud during drilling. Previously used inhibitors of this type are polyglycols that are polymers of ethylene oxide or copolymers of ethylene oxide and propylene oxide differing in molecular weight. The main test confirming the inhibitory properties of scrubbers is the testing of clay rock dispersion, normally carried out under ambient conditions. This article describes dispersion studies under elevated temperature conditions to confirm the inhibitory properties of test agents under conditions similar to wellbore. Dispersion studies were additionally associated with swelling measurements, i.e. volumetric growth of clay rock in the drilling mud environment. Muds containing new types of polyglycols were also tested in borehole-like conditions: tests on the resistance of these muds to divalent metal ions (Ca2+ and Mg2+), solid phase contamination (ground Miocene shale imitating drill cuttings) and increased temperature. The subject matter presented in the article is the result of industry interest in the use of muds with the addition of this type of inhibitors. These agents have similar properties to the previously used polyglycols, but show greater efficiency under well conditions.