Effect Of Higher Alcohols Research Articles

Comparative investigation of the effects of lower and higher alcohols/bio-diesel blends on engine performance and emissions characteristics of a diesel engine

ABSTRACTThe use of lower alcohol (such as methanol and ethanol) blends in diesel engines shows problems like phase separation, miscibility, higher NOx emissions etc. The addition of higher alcohols with either diesel or biodiesel is relatively new and only a little information is available on the effects of higher alcohols. In this work, the engine performance and emissions characteristics were compared between the lower and higher alcohol blended with biodiesel. Conventional diesel and biodiesel are considered as the reference fuels. Three lower alcohols (methanol, ethanol and propanol) and three higher alcohols (butanol, pentanol and octanol) of each 50% by volume were mixed with biodiesel of 50% by volume. Experiments were conducted on a single cylinder compression ignition diesel engine by varying the load conditions at a constant speed. Engine performance and emissions of CO, CO2, NOx and HC were determined. The results are discussed.

On the effects of higher alcohols on red wine aroma

This work aims to assess the aromatic sensory contribution of the four most relevant wine higher alcohols (isobutanol, isoamyl alcohol, methionol and β-phenylethanol) on red wine aroma. The four alcohols were added at two levels of concentration, within the natural range of occurrence, to eight different wine models (WM), close reconstitutions of red wines differing in levels of fruity (F), woody (W), animal (A) or humidity (H) notes. Samples were submitted to discriminant and descriptive sensory analysis.Results showed that the contribution of methionol and β-phenylethanol to wine aroma was negligible and confirmed the sensory importance of the pair isobutanol-isoamyl alcohol. Sensory effects were only evident in WM containing intense aromas, demonstrating a strong dependence on the aromatic context. Higher alcohols significantly suppress strawberry/lactic/red fruity, coconut/wood/vanilla and humidity/TCA notes, but not the leather/animal/ink note. The spirit/alcoholic/solvent character generated by higher alcohols has been shown to be wine dependent.

Comparative analyses of diesel–waste oil biodiesel and propanol, n-butanol or 1-pentanol blends in a diesel engine

Higher alcohols are important alternative fuel resources for use in internal combustion engines promising positive economical and environmental outcomes. Moreover, higher alcohols are advantageous over lower alcohols due to their better blending capabilities, hydrophobic properties, higher cetane numbers and calorific value. The aim of this work is to investigate and compare the basic fuel properties of the ternary blends of diesel (D), waste oil methyl ester (biodiesel (B)) and the higher alcohols of propanol (Pro), n-butanol (nB) and 1-pentanol (Pn), and their effects on engine performance and exhaust emissions of a diesel engine. As test fuels four different blends were prepared by volume: 50%D–50%B (D50B50), 40%D–40%B–20%Pro (D40B40Pro20), 20%nB (D40B40nB20) and 20%Pn (D40B40Pn20). Addition of higher alcohols to diesel–biodiesel blend improved especially the cloud point (CP) and cold filter plugging point (CFPP), while slightly decreased density, lower heating value, kinematic viscosity, cetane number and flash point. In order to determine engine performance and exhaust emissions, tests were performed at four engine loads (1, 3, 6, 9kW) with a constant engine speed (1800rpm). Based on the engine performance and exhaust emissions, D40B40Pro20 had higher brake specific fuel consumption (BSFC) values than the ternary blends of D40B40nB20 and D40B40Pn20 at all engine loads. The exhaust gas temperatures (EGT) of D40B40Pro20, D40B40nB20 and D40B40Pn20 were higher than that of the diesel–biodiesel blend. All blends of the higher alcohols reduced oxides of nitrogen (NOx) emissions as 1-pentanol, n-butanol and propanol were the most to least effective alcohols respectively. However, carbon monoxide (CO) emissions were increased with the addition of the alcohols to the blends. When the effects of higher alcohols on hydrocarbon (HC) emissions are compared in terms of emission reduction, the order from best to worst was as follows: D40B40Pn20, D40B40nB20.

Effect of higher alcohols on the performances of a 1%Rh/MgAl 2O 4/Al 2O 3 catalyst for hydrogen production by crude bioethanol steam reforming

The object of the present study was to study the role of alcohols, which are the major impurities found in a crude bioethanol feed, on the catalytic performances of a 1%Rh/MgAl 2O 4/Al 2O 3 catalyst during ethanol steam reforming. The alcohols studied were methanol, propan-1-ol, butan-1-ol, pentan-1-ol, isopropanol, 2-methyl propan-1-ol, 3-methyl butan-1-ol. Whereas the presence of 1% of methanol in the ethanol and water feed only slightly increased the hydrogen yield, the addition of the same amount of higher alcohols strongly decreased the stability of the catalyst during ethanol steam reforming, with a direct impact on the ethanol conversion and the hydrogen yield. It was shown that the deactivation is increased when the amount of carbon atoms in the molecule is increased. This effect is more pronounced in the presence of branched alcohols compared to the linear ones. It was demonstrated by studying the steam reforming of these higher alcohols that they are dehydrated to the corresponding olefin. The strong deactivation of the catalyst observed in the presence of higher alcohols was explained in terms of coke deposition.

Molecular mechanism of anesthesia.

The up-to-date studies of the molecular mechanism of the anesthesia are reviewed on the emphasis of the non-specific binding of the anesthetics on the lipid membranes. The anesthetic potency for various anesthetics is inversely proportional to the solubility to the olive oil. This fact is related to the depression of the phase transition temperature of lipid membranes caused by varius anesthetics. The effect of higher alcohols upon the phasetransition of lipid membranes is studied and the result is related to the disappearance of the anesthetic potency.