Methyl isobutyl ketone

Abstract: Dehydration of fructose to 5-hydroxymethylfurfural was performed in a batch mode in the presence of a series of dealuminated H-form mordenites as catalysts, at 165°C, and in a solvent mixture consisting of water and methyl isobutyl ketone (1:5 by volume). Under the operating conditions used, the reaction was not controlled by external or internal diffusional limitations. Fructose conversion and selectivity to 5-hydroxymethylfurfural were found to depend on acidic and structural properties of the catalysts used as well as on the micropore vs. mesopore volume distribution of those catalysts. A maximum in the rate of conversion of fructose was observed for the H-mordenite with a Si/Al ratio of 11. A maximum in the selectivity to 5-hydroxymethylfurfural was observed only for H-mordenites with a low mesoporous volume. The high selectivity obtained (>90%) was correlated with the shape selectivity properties of H-mordenites (bidimensional structure), and particularly with the absence of cavities within the structure allowing further formation of secondary products. The influence of the microporosity vs. mesoporosity on the selectivity to 5-hydroxymethylfurfural was also studied, the formation of mesopores upon dealumination procedures being damaging to obtain a high selectivity. A significant increase in the selectivity (10%) was also obtained by simultaneous extraction of 5-hydroxymethylfurfural with methyl isobutyl ketone circulating in a countercurrent manner in a continuous catalytic heterogeneous pulsed column reactor. Finally, taking into account the most recent results reported in the literature and our own results, it is possible to revise the mechanism of the dehydration of fructose.

Abstract: The initial development of additives to stabilize the viscosity of biocrude during long-term storage has produced dramatic results. The additives investigated were ethyl acetate, methyl isobutyl ketone and methanol, acetone, methanol, acetone and methanol, and ethanol. These additives represent three chemical families, which all demonstrated the ability to drastically reduce the aging rate of biocrude, as defined by the increase in viscosity with time. Accelerated aging tests were run at 90 °C to screen the additives. The additives not only lowered the initial viscosity at 40 °C by half but also reduced the aging rate of a hot gas filtered pyrolysis oil made from hybrid poplar (NREL run 175) by factors of 1−18 compared to the original pure oil. With the best additive, methanol, at a 10 wt % level in the pyrolysis oil, the modified biocrude was still a single-phase liquid and still met the ASTM No. 4 diesel fuel specification for viscosity even after 96 h exposure to 90 °C. Based on the aging rate at 90 °C...

Abstract: A technique has been developed for the determination of "soluble" cobalt, copper, iron, lead, nickel and zinc in saline waters by simultaneous extraction of their complexes with ammonium pyrollidine dithiocarbamate (APDC) into methyl isobutyl ketone (MIBK) and subsequent analysis by atomic-absorption spectrophotometry. Particulate matter is analysed separately by dissolving millipore filters in an acetone-hydrochloric acid mixture. Various analytical and instrumental parameters have been evaluated. The method is selfcompensating in that it makes allowance for any incomplete extraction of the complexes. The technique has been applied to the determination of these elements in sea-water and saline lakes.

Abstract: A procedure for analysis and pretreatment of natural-water samples to determine very low concentrations of Al is described which distinguishes the rapidly reacting equilibrium species from the metastable or slowly reacting macro ions and colloidal suspended material. Aluminum is complexed with 8-hydroxyquinoline (oxine), pH is adjusted to 8.3 to minimize interferences, and the aluminum oxinate is extracted with methyl isobutyl ketone (MIBK) prior to analysis by atomic absorption. To determine equilibrium species only, the contact time between sample and 8-hydroxyquinoline is minimized. The Al may be extracted at the sample site with a minimum of equipment and the MIBK extract stored for several weeks prior to atomic absorption analysis. Data obtained from analyses of 39 natural groundwater samples indicate that filtration through a 0.1-μm pore size filter is not an adequate means of removing all insoluble and metastable Al species present, and extraction of Al immediately after collection is necessary if only dissolved and readily reactive species are to be determined. An average of 63% of the Al present in natural waters that had been filtered through 0.1-μm pore size filters was in the form of monomeric ions. The total Al concentration, which includes all forms that passed through a 0.1-μm pore size filter, ranged 2–70 μg/l. The concentration of Al in the form of monomeric ions ranged from below detection to 57 μg/l. Most of the natural water samples used in this study were collected from thermal springs and oil wells.