Direct methane conversion to methanol by ionic liquid-dissolved platinum catalysts

Ternary systems of inorganic Pt salts and oxides, ionic liquids and concentrated sulfuric acid are effective at catalyzing the direct, selective oxidation of methane to methanol and appear to be more water tolerant than the Catalytica reaction

Novel Broadband Amplifier for Mid-Infrared Semiconductor laser and applications in spectroscopy

An amplifier design for broadband Mid-IR buried-hetero (BH) structure epitaxial laser is presented, and external cavity design based on this amplifier is described. Spectroscopy results characterizing such single frequency lasers are demonstrated with whispering gallery mode CaF2 disc/ball, saturated absorption in hollow waveguide and direct chemical analysis in water

Microsensors based on quantum cascade lasers

We present our results on efficient coupling of Quantum Cascade Lasers (QCLs) into Whispering Gallery Resonators, Hollow Waveguide. We also present results of micro sensors using the unique properties of QCLs, e.g. online sensors for Gas Chromatography (GC). We show that because of the unique brightness properties of QCLs, we could improve GC-Infrared sensors' sensitivity to the same level as Mass Spectrometry, and with different dimension of chemical information

Applications of quantum cascade lasers in chemical sensing

We show new results in modulating and modifying Quantum Cascade (QC) lasers to make them more suitable for chemical sensing spectroscopy. Spectroscopy results using QC lasers are demonstrated with whispering gallery mode CaF_2 disc/ball, saturated absorption in hollow waveguide and direct chemical analysis in water

Quantum cascade laser sensors for online gas chromatography

We show that QC laser could improve capillary Gas Chromatography Infrared spectroscopy resolution significantly, i.e. both Doppler limited and Doppler free resolution could be achieved. To achieve these goals, we report our latest efforts in characterizing the tuning and noise properties of Quantum Cascade (QC) lasers; novel schemes on modulation to gain largest tuning range as well as on stabilizing and locking the QC lasers are proposed, and results presented

Partitioning of Poly(amidoamine) Dendrimers between n-Octanol and Water

Dendritic nanomaterials are emerging as key building blocks for a variety of nanoscale materials and technologies. Poly(amidoamine) (PAMAM) dendrimers were the first class of dendritic nanomaterials to be commercialized. Despite numerous investigations, the environmental fate, transport, and toxicity of PAMAM dendrimers is still not well understood. As a first step toward the characterization of the environmental behavior of dendrimers in aquatic systems, we measured the octanol−water partition coefficients (logK_(ow)) of a homologous series of PAMAM dendrimers as a function of dendrimer generation (size), terminal group and core chemistry. We find that the logKow of PAMAM dendrimers depend primarily on their size and terminal group chemistry. For G1-G5 PAMAM dendrimers with terminal NH_2 groups, the negative values of their logK_(ow) indicate that they prefer to remain in the water phase. Conversely, the formation of stable emulsions at the octanol−water (O/W) interface in the presence of G6-NH_2 and G8-NH_2 PAMAM dendrimers suggest they prefer to partition at the O/W interface. In all cases, published studies of the cytotoxicity of Gx-NH_2 PAMAM dendrimers show they strongly interact with the lipid bilayers of cells. These results suggest that the logKow of a PAMAM dendrimer may not be a good predictor of its affinity with natural organic media such as the lipid bilayers of cell membranes

Modeling of gas generation from the Cameo coal zone in the Piceance Basin, Colorado

The gas generative potential of the Cretaceous Cameo coal in the Piceance Basin, northwestern Colorado, was evaluated quantitatively by sealed gold tube pyrolysis. The H/C and O/C elemental ratios show that pyrolyzed Cameo coal samples follow the Van Krevelen humic coal evolution pathway, reasonably simulating natural coal maturation. Kinetic parameters (activation energy and frequency factor) for gas generation and vitrinite reflectance (Ro) changes were calculated from pyrolysis data. Experimental Ro results from this study are not adequately predicted by published Ro kinetics and indicate the necessity of deriving basin-specific kinetic parameters when building predictive basin models. Using derived kinetics for Ro evolution and gas generation, basin modeling was completed for 57 wells across the Piceance Basin, which enabled the mapping of coal-rank and coalbed gas potential. Quantities of methane generated at approximately 1.2% Ro are about 300 standard cubic feet per ton (scf/ton) and more than 2500 scf/ton (in-situ dry-ash-free coal) at Ro values reaching 1.9%. Gases generated in both low- and high-maturity coals are less wet, whereas the wetter gas is expected where Ro is approximately 1.4–1.5%. As controlled by regional coal rank and net coal thickness, the largest in-place coalbed gas resources are located in the central part of the basin, where predicted volumes exceed 150 bcf/mi^2, excluding gases in tight sands

Methyl Chloride from Direct Methane Partial Oxidation: A High-Temperature Shilov-Like Catalytic System

The intention of this study is to demonstrate and evaluate the scientific and economic feasibility of using special solvents to improve the thermal stability of Pt-catalyst in the Shilov system, such that a high reaction temperature could be achieved. The higher conversion rate (near 100%) of methyl chloride from partial oxidation of methane under the high temperature ({approx} 200 C) without significant Pt0 precipitation has been achieved. High concentration of the Cl- ion has been identified as the key for the stabilization of the Pt-catalysts. H/D exchange measurements indicated that the over oxidation will occur at the elevated temperature, developments of the effective product separation processes will be necessary in order to rationalize the industry-visible CH4 to CH3Cl conversion

Applications of quantum cascade lasers in chemical sensing

We show new results in modulating and modifying Quantum Cascade (QC) lasers to make them more suitable for chemical sensing spectroscopy. Spectroscopy results using QC lasers are demonstrated with whispering gallery mode CaF_2 disc/ball, saturated absorption in hollow waveguide and direct chemical analysis in water