This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.

R.B. Lawrance [and] M.W.P. Strandberg. / "October 3, 1950." / Bibliography: p. 16. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B. Dept. of the Army Project No. 3-99-10-022.

No description available.

Formaldehyde is one of the main gases that contribute to poor indoor air quality since it is so widely used in the manufacturing of goods. Over time, formaldehyde leaches out of various materials and reduces the quality of air. Formaldehyde, even at very low concentrations, can cause respiratory problems and a general feeling of unwellness. The World Health Organization (WHO) states that formaldehyde exposure should not exceed 0.08 ppm over a 30 minute period. Therefore, formaldehyde sensors are needed to ensure optimal indoor air quality. Polyaniline (PANI), as well as PANI doped with NiO or NiO and Al2O3, were tested to determine their suitability as sensing materials for formaldehyde. It was found that at higher concentrations of formaldehyde (above 1 ppm), PANI doped with 5% NiO and 15% Al2O3 was the most suitable sensing material with respect to both sensitivity and selectivity. At lower concentrations (below 1 ppm), however, PANI doped with 5% NiO and 15% Al2O3 did not detect formaldehyde. PANI doped with 15% NiO only was a much better option since it was able to detect the highest concentration of formaldehyde at very low concentrations (0.09 ppm) and still have moderate selectivity. A special test system was designed that could test single or multiple gases at various concentrations. Ethanol, acetaldehyde and benzene were chosen as interferents for formaldehyde and nitrogen was used to dilute the gases to achieve lower concentrations. A specialized gas chromatograph (GC) was used to determine the amount of gas or analyte that interacted with the sensing material being tested. Replicate polymer samples of varying dopant concentrations were tested with different gases at different concentrations and statistically analyzed. Both sensitivity and selectivity towards formaldehyde was taken into consideration. Among all tests conducted with single and multiple gases, it was concluded that PANI doped with 5% NiO and 15% Al2O3 was the best sensing material at high concentrations of formaldehyde (above 1 ppm), whereas PANI doped with 15% NiO was the best sensing material at low concentrations (below 1 ppm).

No description available.

Formaldehyde cross-linking has been used to study protein-protein interactions in cells. Its short spacer arm, ability to permeate through cell membrane and the reversibility of the cross-linking reaction makes this a desirable cross-linker for in vivo studies. Although it has been widely used as a cross-linking reagent, the detailed chemistry behind protein cross-linking is not well understood. In vitro studies conducted under extended incubation periods (2 days) have shown that a multitude of amino acids are reactive to formaldehyde and that residue accessibility appears to play a role in reactivity. How applicable these findings are to formaldehyde cross-linking studies done under in vivo conditions (10-20 min incubations) is unclear. The chemistry of formaldehyde cross-linking was therefore investigated in model peptides under conditions similar to those used in in vivo studies. It was observed that only a subset of amino acids (amino termini and side chains of lysine and tryptophan) that were found reactive under extended incubation times was reactive in the much shorter incubation period. No cross-linking was detected between peptides, and elevating the peptide and formaldehyde concentrations resulted in only a minimal amount of cross-linked peptides. The relationship between residue accessibility and formaldehyde reactivity was assessed in model proteins that contain a more complex tertiary structure. It was shown that the extent of formaldehyde reactivity was dependent on the state of protein unfolding, i.e., solvent accessibility of reactive residues, and that an unfolded protein showed a significantly higher number of formaldehyde-induced modifications than a folded form, with lysine being the predominant reactive site. Formaldehyde treatment of proteins in their native form resulted in a low number of modifications even under an increased incubation time, suggesting that the protein remains folded during the course of the reaction. This is important for in vivo cross-linking studies where specificity and stability of protein-protein interactions is dictated by protein tertiary structure.

No description available.

Formaldehyde is one of the main gases that contribute to poor indoor air quality since it is so widely used in the manufacturing of goods. Over time, formaldehyde leaches out of various materials and reduces the quality of air. Formaldehyde, even at very low concentrations, can cause respiratory problems and a general feeling of unwellness. The World Health Organization (WHO) states that formaldehyde exposure should not exceed 0.08 ppm over a 30 minute period. Therefore, formaldehyde sensors are needed to ensure optimal indoor air quality. Polyaniline (PANI), as well as PANI doped with NiO or NiO and Al2O3, were tested to determine their suitability as sensing materials for formaldehyde. It was found that at higher concentrations of formaldehyde (above 1 ppm), PANI doped with 5% NiO and 15% Al2O3 was the most suitable sensing material with respect to both sensitivity and selectivity. At lower concentrations (below 1 ppm), however, PANI doped with 5% NiO and 15% Al2O3 did not detect formaldehyde. PANI doped with 15% NiO only was a much better option since it was able to detect the highest concentration of formaldehyde at very low concentrations (0.09 ppm) and still have moderate selectivity. A special test system was designed that could test single or multiple gases at various concentrations. Ethanol, acetaldehyde and benzene were chosen as interferents for formaldehyde and nitrogen was used to dilute the gases to achieve lower concentrations. A specialized gas chromatograph (GC) was used to determine the amount of gas or analyte that interacted with the sensing material being tested. Replicate polymer samples of varying dopant concentrations were tested with different gases at different concentrations and statistically analyzed. Both sensitivity and selectivity towards formaldehyde was taken into consideration. Among all tests conducted with single and multiple gases, it was concluded that PANI doped with 5% NiO and 15% Al2O3 was the best sensing material at high concentrations of formaldehyde (above 1 ppm), whereas PANI doped with 15% NiO was the best sensing material at low concentrations (below 1 ppm).

This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.

Formaldehyde cross-linking has been used to study protein-protein interactions in cells. Its short spacer arm, ability to permeate through cell membrane and the reversibility of the cross-linking reaction makes this a desirable cross-linker for in vivo studies. Although it has been widely used as a cross-linking reagent, the detailed chemistry behind protein cross-linking is not well understood. In vitro studies conducted under extended incubation periods (2 days) have shown that a multitude of amino acids are reactive to formaldehyde and that residue accessibility appears to play a role in reactivity. How applicable these findings are to formaldehyde cross-linking studies done under in vivo conditions (10-20 min incubations) is unclear. The chemistry of formaldehyde cross-linking was therefore investigated in model peptides under conditions similar to those used in in vivo studies. It was observed that only a subset of amino acids (amino termini and side chains of lysine and tryptophan) that were found reactive under extended incubation times was reactive in the much shorter incubation period. No cross-linking was detected between peptides, and elevating the peptide and formaldehyde concentrations resulted in only a minimal amount of cross-linked peptides. The relationship between residue accessibility and formaldehyde reactivity was assessed in model proteins that contain a more complex tertiary structure. It was shown that the extent of formaldehyde reactivity was dependent on the state of protein unfolding, i.e., solvent accessibility of reactive residues, and that an unfolded protein showed a significantly higher number of formaldehyde-induced modifications than a folded form, with lysine being the predominant reactive site. Formaldehyde treatment of proteins in their native form resulted in a low number of modifications even under an increased incubation time, suggesting that the protein remains folded during the course of the reaction. This is important for in vivo cross-linking studies where specificity and stability of protein-protein interactions is dictated by protein tertiary structure.