Search results for "ethanol"
showing 10 items of 2041 documents
Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]
2021
Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orie…
Proton Conducting Membrane Prepared by Cross-Linking Highly Sulfonated Peek for PEMFC Application
2009
The proton conducting membrane was prepared by cross-linking highly sulfonated and sulfinated poly(etheretherketone) (SsPEEK). The cross-linked membrane is low cost due to its use of non-expensive chemical and simple production procedure. The membrane exhibited high proton conductivity (0.04 S/cm at 60 °C), extremely reduced water uptake, enhanced strength and stability compared with that of non-cross-linked membrane. These results suggested that the cross-linked PEEK membrane is a suitable candidate of proton conducting membranes for polymer electrolyte membrane fuel cell (PEMFC) applications, particularly promising to be used in direct methanol fuel cell (DMFC) due to its lower methanol c…
Studien zum Vorgang der Wasserstoffübertragung 46. Zur kathodischen Spaltung von Alkyl- und Cycloalkyl(triphenyl)-phosphoniumsalzen; Abhängigkeit der…
1977
Die kathodische Spaltung von Methyl-, Butyl- und einiger Cycloalkyl(triphenyl)phosphoniumsalze wurde potentiostatisch und galvanostatisch durchgefuhrt. Beim Methyl(triphenyl)-phosphoniumsalz hangt die prozentuale Zusammensetzung der Spaltprodukte: Triphenylphosphin und Methyl(diphenyl)phosphin sowohl vom Potential als auch von der Temperatur ab, die sich ihrerseits wieder gegenseitig beeinflussen. Zusatze unterschiedlich strukturierter quartarer Ammoniumsalze als Leitsalz verandern das prozentuale Verhaltnis (C6H5)3P/(C6H5)2PCH3 nicht, wohl aber der Zusatz von Essigsaure, welche die Bildung von Methyl(diphenyl)phosphin begunstigt. - Bei den Cycloalkyl(triphenyl)phosphoniumsalzen mit Cyclohe…
Moss cell cultures as sources of arachidonic and eicosapentaenoic acids
1986
AbstractLipid classes from tissue cultures of the moss Leptobryum pyriforme (Hedw.) Wils. were analyzed. In the total lipid fraction, this species contained 20% arachidonic acid and about 7% eicosapentaenoic acid. The distribution of these fatty acids showed a preference for the phospholipid fraction. In particular, the phosphatidylethanolamine fraction was enriched in arachidonic acid. The arachidonic acid content of Leptobryum could be altered by transferring the cultures to different culture conditions. Mosses show high organic mass production in tissue cultures in relatively simple media. The great potential of using mosses as sources for the production of polyunsaturated fatty acids is…
Nonionic Maleic Surfmers
2002
ABSTRACT A set of nonionic maleic surfactants have been prepared, all coming from the derivatization of maleic hemiesters with a long alkyl chain. They are either amidoesters or diester products. In the case of amidoesters, the acid group was first activated and then reacted with primary or secondary or tertiary ethanolamine compounds. In the case of diesters, the hemiester was reacted directly with glycidol, in acid or basic conditions. These surfactants were characterized for their structure by 1H NMR, and for their surface active properties, by surface tension measurements. They were also used in batch emulsion polymerisation of styrene, and seeded core-shell copolymerisation of a 1/1 mi…
Electron-transfer reduction of selected alcohols with alkalide K−, K+(15-crown-5)2 via organometallic intermediates
2004
Abstract The course of the reaction of alkalide K − , K + (15-crown-5) 2 1 with selected alcohols depends on the kind of alcohol and the mode of substrate delivery. In the case of methanol, potassium methoxide formed initially undergoes destruction at the excess of 1 . It results in potassium oxide and methylpotassium. The latter opens the crown ether ring giving potassium tetraethylene glycoxide vinyl ether and methane. A similar course of the process is observed for propanol. Potassium glycidoxide is the main product formed in the reaction of 1 with glycidol. Its oxirane ring is opened at the excess of 1 . Organopotassium alkoxides, i.e., potassium potassiomethoxide and dipotassium potass…
Ion pair association in isodielectric mixtures at 25�C
1974
Conductance measurements of potassium perchlorate and iodide have been carried out on the following mixtures: methanol-ethylene carbonate, acetone-ethylene carbonate, acetonitrile-ethylene carbonate, sulfolane-ethylene carbonate, isodielectric with water; and in benzene-sulfolane, benzene-acetonitrile, ethanol-sulfolane, isodielectric with methanol. The extent of ionic association at a given concentration in two solvents of the same dielectric constant is greater in the aprotic solvent.
Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home-prepared titanium dioxide
2008
Abstract Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterization of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA convers…
Isobaric Vapor−Liquid Equilibria for Binary and Ternary Mixtures of Ethanol and 2-Propanol with 2-Butanone and Butyl Propionate at 101.3 kPa
2009
This paper presents vapor−liquid equilibrium (VLE) data at 101.3 kPa for the ternary systems ethanol + 2-butanone + butyl propionate and 2-propanol + 2-butanone + butyl propionate and some of their...
Biotechnological characterisation of exocellular proteases produced by enologicalHanseniasporaisolates
2014
Summary Twenty-six enological Hanseniaspora isolates were identified by ITS PCR-RFLP and D1/D2 domain of 26S rDNA sequencing and assayed for exocellular protease production. Based on qualitative data, six isolates, belonging to H. guilliermondii, H. valbyensis and H. occidentalis species, were selected to continue the study. Analytical procedure was optimised, and protease activities were quantified and characterised on the basis of different biotechnological factors. Protease activity was quite glucose, fructose and ethanol content independent, but divalent cation affects activity; these data support that they were aspartic proteases. The effect of 2-mercaptoethanol suggests the importance…