Halogens, research needed

The preceding are examples of some of the rich chemistry and kinetics that are still unknown about the rare gas halide lasers. Many other examples abound, but they are either not yet the subject of current research or there is still a significant amount of additional research needed. These include the kinetics of specific (v, J) states in XeF (a bound-bound laser transition), any quantitative understanding of ArF (one of the more potentially useful lasers), measurements of halogen bumup phenomena in KrF lasers, electron temperatures or distributions, the energy to produce an ion pair in actual laser mixtures, and a host of other challenging puzzles. On top of these "chemical physics" challenges there still remain numerous... 

Finally, the results obtained with the nitroreductase-deficient strain TA100 indicated that a chlorination step during drinking water treatment is able to produce and/or activate mutagenic nitro-organics. However, much more research is needed to elucidate the precise nature of these nitro (halogenated) aromatics and the mechanisms by which they are formed. 

Natural products represent an unparalleled source of molecular diversity for innovative drug discovery. In the pharmaceutical industry, there is an urgent need to identify novel lead structures for effective drug development in many therapeutic areas. It is likely that natural halogen compounds will continue to contribute leads to future research. 

A method has been claimed for improving partial oxidation yield using a homogeneous catalyst with air or 02 processes using catalytic amounts of halogens have been patented by Petrotex (6) and by El Paso Natural Gas Products Co. (55). The latter claims that if reactants having catalyst oxidant propane ratio of 0.15 lbs I2 3.0 lbs 02 1 lb C8H8 are processed at 1200°F, 1 atm, and 0.05 minutes contact time, propane conversion of 72% and selectivity of 59 mole % are achieved. For reference, catadiene conversion and selectivity are 54% and 75.6 mole %, respectively, and research efforts to increase El Paso s partial oxidation yields past this level will be needed to effect an economic process in which iodine values are recovered and recycled. 

Electrochemical treatment could also be used to disinfect urine before it is used as a fertilizer. The most likely process is electrochemical chlorine formation. However, indirect electrooxidation via chlorine can lead to unwanted by-products such as chlorate, perchlorate, and halogenated organic compounds [12]. More research is needed to determine whether and how the formation of unwanted by-products can be prevented. 

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