Desiccant based dehumidification allows for independent treatment of latent and sensible properties in air conditioning systems and enables the use of energy-saving solar thermal evaporative cooling systems. These systems can reduce dependence on vaporcompression air conditioning which is a significant source of greenhouse gases. Recent research has focused on polymer-based desiccant materials which have higher adsorption capacities than conventional materials such as silica gel and zeolite. Solid desiccant materials used in dehumidification systems are typically utilized in a cycle in which they absorb water vapor from a process air stream and are then regenerated by a source of hot, dry air which evaporates and removes water contained in the material, allowing it to again absorb water from the process air. This research focuses on the development and testing of a hygroscopic salt impregnated, NIPAM hydrogel-based thermo-responsive desiccant material that can be regenerated by elevating the material to its lower critical solution temperature (LCST), enabling a significant energy saving over materials that require regeneration through water evaporation. At this LCST, the water adsorbed by the desiccant becomes insoluble in its NIPAM polymer matrix and is removed through droplet formation induced by gravity. Adsorption and regeneration testing was performed on the material to evaluate the feasibility of using this temperature-sensitive desiccant into a dehumidification system. Testing shows this composite material has a maximum SR of > 2 and analysis indicates improvement in regeneration heat requirements over existing desiccant materials.

The development of efficient methods for the formation of carbon-nitrogen bonds is of great interest in organic chemistry. While traditional approaches to C-N bond formation are well developed and have found widespread use, approaches utilizing an electrophilic source of nitrogen are vastly underdeveloped. Although a number of electrophilic sources of nitrogen have been developed, the efforts of our research have centered on the use of nitrosocarbonyl compounds. Due to their high reactivity, nitrosocarbonyl intermediates can only be generated in situ and are classically obtained from the oxidation of hydroxamic acid derivatives using periodate salts. However, this in situ oxidation protocol, which is commonly used in the hetero-Diels-Alder (HDA) reaction, is incompatible with the other reactions because the initially formed adduct is highly susceptible to decomposition. While this has significantly limited the development of chemistry utilizing nitrosocarbonyl compounds, we postulated that if the oxidation conditions were mild enough to circumvent product decomposition, nitrosocarbonyls could be utilized in a wide variety of C-N bond-forming reactions.

Recently, we reported the first example of the aerobic generation of nitrosoformate intermediates for use in the nitroso ene reaction. The aerobic oxidation method, which relies on the use of catalytic amounts of CuCl (5 mol %) and uses air as the terminal oxidant, proved mild enough to avoid decomposition of the ene adducts, affording the allylic hydroxylamines in up to quantitative yields. Additionally, the oxidation protocol is highly general for a wide variety of N-substituted hydroxylamines; the Diels-Alder reaction can be carried out in up to quantitative yields employing an array of nitroso compounds. Moreover, by switching to photoredox conditions using Ru(bpy)3Cl2, the nitrosocarbonyl intermediates can be efficiently generated with temporal and spatial control.

As proposed, the mild oxidation conditions allowed the expansion of nitrosocarbonyl chemistry into new areas, such as the nitroso aldol reaction. Through the synergistic combination of our aerobic oxidation with known Lewis acid activation of beta-ketoesters, the alpha-amination and alpha-oxygenation of carbonyl compounds was achieved for the first time using nitrosocarbonyl compounds. All of the reactions are operationally simple to perform, utilize reagent grade solvents and air as the terminal oxidant, and the only byproduct is water.