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Determinación de agua en colodión-Método de Karl FisherEspinosa Descalzo, Elizabeth Norma January 1993 (has links)
En el presente trabajo se propone un método analítico para la determinación de agua en "colodión de acetato"; que es una disolución de acetato de celulosa secundario en acetona, llamado asi en la industria hilandera por BU consistencia y apariencia similar al colodión de nitrocelulosa.
El colodión de acetato constituye un caso problemático del método Klarl Fieher: Las catona a reaccionan con metanol en medio ácido para dar acetalee yagua.
La solución Karl Fisher recomendada es del tipo estabilizada (libre de metanol), determinándose el punto final en forma amperométr!ca por la técnica del punto muerto.
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An Investigation of the Storage Stability of Auger and Entrained Flow Reactor Produced Bio-oilsMohammad, Javeed 01 May 2010 (has links)
This project is primarily focused on improving the storage stability of bio-oils or pyrolysis oils by varying feedstock, reactor, and storage conditions. Pyrolysis oil is a complex medley of oxygenated chemicals (aliphatic and aromatic) that are well known to undergo unstable polymeric reactions (auto-catalyzed) if suitable additives are not utilized. These reactions can be severely detrimental to the long-term storage stability of pyrolysis oils. Hence, a detailed investigation was conducted in four phases namely: 1) pyrolysis oil production 2) additive prescreening 3) concentration optimization and 4) stability testing. During the first phase a lab-scale semi-continuous auger reactor is utilized to produce 16 pyrolysis oils. The reactor variables include pyrolysis temperature and vapor residence time. The feed stocks include pine wood, pine bark, oak wood, and oak bark. During the second phase a range of chemical additives (26) are prescreened to obtain three best performing additives. Anisole, glycerol, and methanol are consequently utilized to perform concentration optimization studies during the third phase. Viscosity, water content, and pH of pyrolysis oils are timely measured to assess the accelerated storage stability of pyrolysis oils during the phases 2-3. During the fourth phase, pyrolysis oils produced from three different reactor systems (lab-scale auger, large-scale auger, and entrained flow) were tested for their storage stability. Viscosity, water content, pH, density, and acid value are timely measured to assess the ambient and accelerated storage stability of pyrolysis oils during phase 4. Extrinsic variables such as light and filtration are utilized during the experimental testing of phase 4. The rheological data (Newtonian/non-Newtonian) enhanced the understanding of pyrolysis oil storage stability both qualitatively and quantitatively. The stability performance of a chemical additive is very much dependent on the concentration and its organic functional group. Consequently, alcohols fared above all the other functional groups in stabilizing the pyrolysis oils. Glycerol is observed to have special blending and homogenizing properties compared to all other additives. Feedstock seems to be the single most important factor affecting storage stability of pyrolysis oils. Consequently, pine wood resulted in the most stable pyrolysis oil whereas pine bark resulted in the least stable pyrolysis oil.
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