No abstract

In this study, FTIR spectroscopy and solid-state magic angle spinning (MAS) NMR were used to investigate the adsorption and thermal reaction of the nerve gas simulant dimethyl methylphosphonate (DMMP) in nanocrystalline NaY with a crystal size of approximately 30 nm. DMMP adsorbs molecularly in nanocrystalline NaY at 25 degrees C. Gas-phase products of the reaction of DMMP and oxygen in nanocrystalline NaY at 200 degrees C were monitored by FTIR spectroscopy and determined to be carbon dioxide (major product), formaldehyde, and dimethyl ether. In the presence of water, the thermal reaction of DMMP in nanocrystalline NaY at 200 degrees C yielded methanol (major product), carbon dioxide, and dimethyl ether. When the thermal reaction of DMMP in nanocrystalline NaY at 200 degrees C was conducted in the presence of water and oxygen, the predominant products were methanol and carbon dioxide. Hydroxyl sites located on the external zeolite surface were consumed during the DMMP thermal reactions as monitored by FTIR spectroscopy and were therefore determined to be the active sites in this reaction. 31P solid-state MAS NMR experiments were used to identify the surface-bound phosphorus complexes. The reactivity per gram of zeolite was comparable to other recently studied metal oxides such as MgO, Al2O3, and TiO2, and was found to have comparable, if not higher reactivity. Future improvements in reactivity may be achieved by incorporating a reactive transition metal ion or metal oxide nanocluster into the nanocrystalline NaY to enhance reaction rates and to achieve complete reaction of DMMP.

No abstract

Because of new regulations on the allowable aromatic content in petroleum products, the saturation of aromatics in distillates and heavy naphtha is gaining more attention. Catalytic hydrodearomatization (HDA) improves the qualities and properties of distillates for health, food, and pharmaceutical applications. In this research, the aromatic content of the four different middle distillate fractions varies from 10 to 12% volume. The goal is to saturate the aromatics to <0.1% volume at pressures, temperatures, and space velocities that are optimized for the lowest operating cost and longest catalyst life. Additionally, this study aims to determine if HDA is more favorable for processing the individual distillate cuts or the comingled products. This study also utilizes a modified high-performance liquid chromatography refractive index (HPLC-RI) method in which an ultraviolet (UV) detector is used to measure low levels of aromatics. A combination of UV and HPLC techniques was able to quantify aromatic levels as low as 0.03% v/v and 0.01% v/v, respectively.

No abstract