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Präzisions-Dichtemessungen von Propan, Propylen, n-Butan und Isobutan sowie Entwicklung eines Normdichtemessgerätes für die ErdgasindustrieGlos, Stefan. January 2004 (has links) (PDF)
Bochum, Univ., Diss., 2004. / Computerdatei im Fernzugriff.
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The kinetics of the thermal dissociation of propane and the butanes ...Durgan, Elford Sturtevant, January 1900 (has links)
Thesis (Ph. D.)--Princeton University, 1930. / Description based on print version record.
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A study of the pyrolysis of normal butane with steam ...Witham, William Clifford, January 1934 (has links)
Thesis (Ph. D.)--Columbia University, 1934. / Vita. Description based on print version record. Bibliography: p. 31-32.
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Präzisions-Dichtemessungen von Propan, Propylen, n-Butan und Isobutan sowie Entwicklung eines Normdichtemessgerätes für die ErdgasindustrieGlos, Stefan. January 2004 (has links) (PDF)
Bochum, Universiẗat, Diss., 2004.
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Mixtures of hard spheres and real gas : the system Helium-N-Butane /Jones, Allan January 1964 (has links)
No description available.
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The photolysis of 1,1'-Azo-n-butane : the reactions of the n-butyl radical /Morganroth, Wayne Everest January 1965 (has links)
No description available.
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N-butane activation over ruthenium and iron promoted VPO catalysts.January 2009 (has links)
The Fe- and Ru-promoted vanadium phosphorus oxide (VPO) catalysts were synthesized via the organic route in iso-butanol to form the VPO precursor, VOHPO4·0.5H2O. The resulting precursor was then activated in a stream of nitrogen to form an amorphous (VO)2P2O7, which crystallized after conditioning in the reactor in the presence of n-butane. The promoted catalysts were synthesized at 0.1%, 0.3% and 1% loading, pelletized and sieved to give a 300-600 μm pellet size. The catalysts were tested in a fixed-bed continuous flow micro-reactor and the products were analyzed by GC’s equipped with a flame ionization detector (FID) to monitor maleic anhydride and n-butane and a thermal conductivity detector (TCD) to monitor the carbon oxides. A range of characterization techniques were employed to determine the influence of the promoting elements on a VPO catalyst and to associate the composition of the catalysts obtained from such techniques with their performance. The characterization techniques used include X-ray diffraction (XRD), BET-surface area, ICP-OES, EDS, 31PNMR, TPR, redox titrations, ATR and SEM to determine the phase composition of the catalysts, the surface area of the promoted catalysts relative to the un-promoted VPO, elemental mole ratios, the reducibility of the catalysts, average vanadium oxidation state, determination of the anions present in the surface of the catalysts and the variations in the morphology of the catalysts,
respectively. Optimization of the system involved variation of the GHSV, the reactor temperature and the promoter loading. (Activation of a 0.75% n-butane in air mixture was performed at an optimum
temperature of 400oC while varying the gas hourly space velocity to establish a range of feed conversions and subsequently determine the activity of each catalyst with respect to n-butane conversion). The promoted catalysts modified the morphology of the catalysts as evidenced by the scanning electron microscopy and the X-ray diffraction patterns. Furthermore an improved conversion was obtained with these catalysts. However, only the 0.1% iron-promoted catalyst improved maleic anhydride yield leading to ca. 10% maleic anhydride yield increment. Yields of 46% and 55% were obtained at GHSVs of 2573 and 1450 per hour respectively and a temperature of 400oC. Electronic and structural modifications were encountered leading to an improved catalytic performance. The performance of this catalyst is associated with a vanadyl pyrophosphate phase (XRD), and a limited and controlled amount of V5+ species as
illustrated in the TPR, and solid state 31P NMR data. Moreover, this modification can be considered both structural and electronic in nature as observed in the SEM images and FTIR spectra of this catalyst. Furthermore, this improved performance is possible at higher conversions 80 to 90% conversion. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.
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Biochemical, molecular and physiological characterization of 1-butanol dehydrogenases of Pseudomonas butanovora in butane and 1-butanol metabolismVangnai, Alisa S. 17 May 2002 (has links)
Butane-grown Pseudomonas butanovora oxidized butane by a soluble
butane monooxygenase through the terminal pathway yielding 1 -butanol as the
predominant product. Alcohol dehydrogenases (ADHs) involved in butane
oxidation in P. butanovora were purified and characterized at the biochemical,
genetic and physiological levels. Butane-grown P. butanovora expressed a type I
soluble quinoprotein 1 -butanol dehydrogenase (BOH), a soluble type II
quinohemoprotein 1 -butanol dehydrogenase (BDH) and an NAD���-dependent
secondary ADH. Two additional NAD���-dependent secondary ADHs were also
detected in cells grown on 2-butanol and lactate. BDH was purified to near
homogeneity and characterized. BDH is a monomer of 66 kDa consisting of one
mole of pyrroloquinoline quinone (PQQ) and 0.25 mole of heme c as the prosthetic
groups. BOH was partially purified and its deduced amino acid sequence suggests
a 67-kDa ADH containing a PQQ as a cofactor. BOH and BDH exhibited high
activities and preference towards I -butanol and fair preference towards
butyraldehyde. While BDH could not oxidize 2-butanol, BOH is capable of
2-butanol oxidation and has a broader substrate range than that of BDH. Genes
encoding BOH and BDH and their deduced amino acid sequences were identified.
BOH and BDH mRNAs and 1-butanol oxidation activity were induced when cells
were exposed to butane. Primary C��� and C��� alcohols were the most effective
inducers for boh and bdh. Some secondary alcohols, such as 2-butanol, were also
inducers for BOH mRNA, but not for BDH mRNA. Insertional inactivation of boh
or bdh affected unfavorably, but did not eliminate, butane utilization in
P. butanovora. The P. butanovora mutant strain with both boh and bdh genes
disrupted was unable to grow on butane and 1-butanol. This result confirmed the
involvement of BOH and BDH in butane and 1-butanol metabolism in
P. butanovora. Roles of B011 and BDH in butane and 1-butanol metabolism were
further studied at the physiological level. There are no substantial differences
between BOH and BDH in the mRNA expressions in response to three different 1-
butanol levels tested and in their abilities to respond to 1-butanol toxicity.
Different bioenergetic roles of BOH and BDH in butane and 1-butanol metabolism
were suggested. A model of 1 -butanol- dependent respiratory systems was
proposed where the electrons from 1 -butanol oxidation follow a branched electron
transport chain. The role of BOH was suggested to function primarily in energy
generation because B011 may couple to ubiquinone with the electrons being
transported to a cyanide-sensitive terminal oxidase. BDH may be more important
in the detoxification of 1 -butanol because the electrons from BDH may be
transferred to a terminal oxidase system that is less sensitive to cyanide, which is
not capable of energy generation. / Graduation date: 2003
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Modeling cometabolic transformation of a CAH mixture by a butane utilizing cultureMathias, Maureen Anne 26 September 2002 (has links)
The goal of this research was to mathematically simulate the ability of
bioaugmented microorganisms to aerobically cometabolize a mixture of chlorinated
aliphatic hydrocarbon (CAH) compounds during in-situ treatment. Parameter values
measured from laboratory experiments were applied to the transport model with
biotransformation processes included. In laboratory microcosm studies, a butane-grown,
enriched culture was inoculated in soil and groundwater microcosms and
exposed to butane and several repeated additions of 1,1,1-trichloroethane (TCA), 1,1-dichioroethylene (DCE), and 1,1-dichloroethane (DCA) at aqueous concentrations of
200 ��g/L, 100 ��g/L, and 200 ��g/L, respectively. Microcosms containing the
bioaugmented culture showed 1,1-DCE to be rapidly transformed, followed by slower
transformation of 1,1-DCA and 1,1,1-TCA. After most of the butane had been
consumed, transformation of these latter CAHs increased, indicating strong inhibition
by butane. With repeat biostimulations, butane utilization and CAH transformation
accelerated, showing the increase in cell mass. These trends occurred in two sets of
microcosm triplicates. No stimulation was observed in controls containing only the
microorganisms indigenous to Moffett Field, confirming that activity seen in the
bioaugmented microcosms was a result of the introduced culture's activity.
Batch reactor results were simulated using differential equations accounting for
Michaelis-Menten kinetics, transformation product toxicity, substrate inhibition, butane
utilization, and CAH transformation. The equations were solved simultaneously by
Runge-Kutta numerical integration with parameter values adjusted to match the
microcosm data.
Having defined the parameter values from laboratory studies, the
biotransformation model was combined with 1-D advective-dispersive transport to
simulate behavior of the culture and the substrates within an aquifer. The model was
used to simulate the results of field studies where the butane-utilizing culture was
injected into a 7 m subsurface test site and exposed to alternating pulses of oxygen and
butane, along with the contaminant mixture studied in the microcosms. Monitoring
wells spaced at 1 m, 2.2 m, and 4 m from the injection well allowed temporal and
spatial changes in substrate concentrations to be determined. Model simulations of the
field demonstration were performed to determine how well the biotransformation/solute
transport model predicted actual field observations.
To model the influences of solute transport, simulations were run and compared
to breakthrough test data (prior to bioaugmentation) to determine the values for
advection, dispersion, and sorption. The simulations showed that flow ranged from 1.0
to 1.5 m��/day (average linear velocity of 2.0 m/day). Dispersion was estimated as 0.31
m��/day. Sediment sorption partitioning coefficients for 1,1-DCE, 1,1-DCA, and 1,1,1-TCA were determined to be approximately 0.69, 0.50, and 0.50 L/kg, respectively. It
was more difficult to determine an appropriate value of the mass transfer rate
coefficient for non-equilibrium sorption, so simulations were run to compare
equilibrium and non-equilibrium cases. Results indicated that non-equilibrium (with
mass transfer rate coefficient of approximately 0.2 day�����) better simulated the field data.
Using these transport parameters and the biotransformation values determined
from the laboratory experiments, simulations of the field data showed that the model
was capable of simulating the effects of transformation rates, butane inhibition, and
1,1-DCE product toxicity. Simulations for varying pulsing cycles and durations
provided possible improvements for future field demonstrations.
Overall, this work proved that there is good potential in extrapolating laboratory
based kinetics to simulate biotransformation at a field scale. Although the complexity
of such systems makes modeling difficult, such simulations are useful in understanding
and interpreting field data. / Graduation date: 2003
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Acidity and catalytic activity of zeolite catalysts bound with silica and aluminaWu, Xianchun 30 September 2004 (has links)
Zeolites ZSM-5 (SiO2/Al2O3=30~280) and Y(SiO2/Al2O3=5.2~80) are bound with silica gel (Ludox HS-40 and Ludox AS-40) and alumina (γ- Al2O3 and boehmite) by different binding methods, namely, gel-mixing, powder-mixing and powder-wet-mixing methods. The acidities of the bound catalysts and the zeolite powder are determined by NH3-TPD and FTIR. The textures of these catalysts are analyzed on a BET machine with nitrogen as a probe molecule. The micropore surface area and micropore volume are determined by t-plot method. Micropore volume distribution is determined by Horvath-Kawazoe approach with a cylindrical pore model. Mesopore volume distribution is determined by BJH method from the nitrogen desorption isotherm. Silica from the binder may react with extra-framework alumina in zeolites to form a new protonic acid. SiO2-bound catalysts have less strong acidity, Bronsted acidity and Lewis acidity than the zeolite powder. Also, the strength of strong acid sites of the zeolites is reduced when silica is embedded. Micropore surface area and micropore volume are reduced by about 19% and 18%, respectively, indicating some micropores of ZSM-5 are blocked on binding with silica. SiO2-bound ZSM-5 catalysts have less catalytic activity for butane transformation (cracking and disproportionation) and ethylene oligomerization than ZSM-5 powder. When alumina is used as a binder, both the total acid sites and Lewis acid sites are increased. Micropore surface area and micropore volume of ZSM-5 powder are reduced by 26% and 23%, respectively, indicating some micropores of ZSM-5 are blocked by the alumina binder. Alumina-bound catalysts showed a lower activity for butane transformation and ethylene oligomerization than ZSM-5 powder. Alkaline metals content in the binder is a crucial factor that influences the acidity of a bound catalyst. The metal cations neutralize more selectively Bronsted acid sites than Lewis acid sites. Alkaline metal cations in the binder and micropore blockage cause the bound catalysts to have a lower catalytic activity than the zeolite powder.
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