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Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Fusel oil is an impurity in the ethanol production process, from which high value-added products such as esters can be obtained. Objective: To experimentally obtain isoamyl acetate by taking advantage of the heavy fraction (>132 °C) separated in the distillation of fusel oil. Materials and Methods: The experimental study was carried out in four stages: dehydration of the fusel oil by liquid-liquid extraction with a saturated sodium chloride solution, using anhydrous sodium sulfate as a drying agent; separation of the alcohols present by distillation, esterification and purification of the final product. In the esterification, a Plackett- Burman design of experiments was performed analyzing the effect, on the yield, of the variables: feed ratio, reaction time and amount of catalyst. Results and Discussion: The water removed represented 24 % of the initial fusel oil sample and upon distillation and characterization by gas chromatography, the working fraction (>132 °C) was found to contain 95.09 % w/w isoamyl alcohol. The highest yield of isoamyl acetate was achieved in experiment IV, when using an acid/alcohol feed ratio of 1.2, 60 min of reaction and 0.5 % w/w catalyst, obtaining in the purification the ester at 98.01 % w/w. Conclusions: The fusel oil used contained ethanol, n-propanol, isobutanol and isoamyl alcohol. The esterification of the heavy fraction, with greater presence of isoamyl alcohol, allowed obtaining its corresponding ester with high levels of purity. [ABSTRACT FROM AUTHOR]

Copyright of Agroindustrial Science is the property of Agroindustrial Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The apparent molar volumes and viscosity of DL-alanine in aqueous solutions of sodium sulfate, Na2SO4, at different molalities and in the temperature range (283 to 308) K at each 5K were determined from density measurements and flow times, using a vibratory tube densimeter Anton Paar DMA 5000 and an automatic viscometer AMVn, respectively. From these data, the: limiting apparent molar volumes and limiting apparent volumes of transfer, hydration numbers, viscosity coefficients of the Jones-Dole equation, and thermodynamic activation parameters of the viscous flow were calculated. The results indicate that the amino acid behaves as a structure-forming solute on the structure of the solvent, followed by an increase in the overall structure of the water. It is concluded that the formation of the transition state is accompanied by the establishment of intermolecular bonds and a more orderly structure of the species in the activated state. [ABSTRACT FROM AUTHOR]

A self-setting mixture for foundry core with sodium silicate as hardener and sugar cane molasses as breakdown agents is studied. In order to achieve this, a full factorial experiment that uses relations of components (32) was designed. The responses variables used were the compression resistance after 24 hours and the demolding. It was selected a mixture of good properties for each of the different zones of relationship between the sodium sulfate and sodium silicate content. The study of the moisture sorption-desorption kinetics of these mixtures when they are located in environments between 60 and 90 % RH was carried out by using gravimetric techniques and the classical diffusion theory. Finally, the mixture that offers the best properties was selected and some technological recommendations for its use were offered. [ABSTRACT FROM AUTHOR]

The article offers information on the importance of salt supply in 16th century in Spain. It states that the salt had a wide range of usage like for the preparation and conservation of tuna in brine, and for the preservation of fresh and green tuna during transport. It mentions that around 5000 salt cakes were consumed per year in the 16th century.

Copyright of Revista Luna Azul is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The corrosion behavior of three types of steels, pre-oxidized and without pre-oxidation, coated with sodium sulfate was evaluated in the present work by using electrochemical techniques, including polarization resistance, Tafel curves, electrochemical impedance, and gravimetric techniques like weight gain, at 600 and 650 °C. It was determined that the steel exhibiting the lowest corrosion rate was 304H, being the most resistant coated specimen with solid Na2SO4 in air atmosphere because its oxide layer formed initially was maintained even at high temperatures. For ferritic steels, a slight increase in corrosion rate was noted, presenting a small diffusion of sulfur and sulfide formation at the alloy /oxide interface, given that it fractured due to the difference in the thermal expansion coefficients. In general, a solid Na2SO4 deposit over the steels used in systems working at high temperatures is not a risk factor that influences material degradation. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The object of this study was inhibiting the browning process during the drying of banana Roatán (Musa Cavendish) using a solution of cactus mucilage (Opuntia ficus indica) blend with different concentrations of citric acid and sodium bisulphite. The treatment was applied following an experimental design 23, using the following factors and levels: pre-treatment (mucilage, citric acid, sodium bisulphate) and concentration (high and low). For the drying cross sections of banana with thickness of 5 mm, temperature of 50 °C and air velocity of 2 ms-1 were used. Color before and after drying was determined and was consider as the response variable. The combination of mucilage, citric acid and sodium bisulphite at high concentrations had a synergic effect that diminished the browning of bananas during drying. The mucilage formed an edible coating in the surface that gives shine to the dried material. [ABSTRACT FROM AUTHOR]

The name of Michel Jean Jérôme Dizé (1764-1852) is intertwined with that of Nicolas Le Blanc (1742-1806) in the Greek tragedy about the birth and infancy of the industry of synthetic sodium carbonate. He was actively involved in most of the failed intents to obtain an indemnification for the heavy losses incurred as a consequence of the expropriation of the factory by the Revolutionary French government. Contrary to Le Blanc, who committed suicide, Dizé succeeded in extricating himself from the tragedy and live a full professional life thereafter. He was not an outstanding scientific figure, but his name is associated with the question of paternity of the chemical process that led to synthetic carbonate, and his claims for part of the benefits. [ABSTRACT FROM AUTHOR]

The woolly whitefly Aleurothrixus floccosus (Maskell) and the red citrus red mite Panonychus citri (McGregor), are considered serious citrus pests which may cause economic damage, and the use of non selective insecticides increases the problem due to the effect on the natural enemies. To evaluate the use of detergent based on sodium benzene sulfonate on the reduction of whiteflies, mites and natural enemies, experiments were performed in two citrus orchards. The first field trial was carried out on in a mandarin orchard (Citrus reticulata Blanco) infested by the woolly whitefly at El Palqui (IV Region, Chile). The experiment consisted of the evaluation of two applications of detergent (February 10th and March 3rd, 1998), compared with an untreated control. The results showed significant differences in A. floccosus populations between sprayed and untreated trees from May to July. The mean of parasitized nymphs between March and August was 89.6% in treated trees and 57.1% in untreated trees. The proportion of fruits at harvest with sooty mould was lower on untreated trees compared with the control, 2.3% and 45.5%, respectively. The second field trial was carried out on an orange orchard trees (Citrus sinensis (L.) Osbeck), infested by the citrus red mite at Hijuelas (V Region) and included the following applications: detergent, chinometionate, mineral oil and water. Chinometionate produced an effective control of the phytophagous mites populations and an almost total elimination of natural enemies such as phytoseiids and the coccinellid Stethorus histrio Chazeau. The application of detergent and mineral oil showed less control compared to the acaricide and less impact on populations of natural enemies. [ABSTRACT FROM AUTHOR]