Supported micelles in biphasic oxidation catalysis

The research is concerned with a novel way of heterogenising a simple water-soluble salt, ammonium molybdate for catalytic cyclohexene oxidation with tert-butyl hydroperoxide (TBHP) in bulk dichoromethane. Surface tethered surfactant molecules created were presumed to form supported micellar assemblies. These assemblies carried microscopic water droplets in turn containing the ammonium molybdate catalyst for use in a biphasic oxidation reaction. Thus heterogenisation of the water-soluble molybdate was accomplished through water droplet immobilisation but without anchoring the catalytic component directly. Our results clearly showed that a faster oxidation rate was obtained using the silica supported with surfactant molecules than with the corresponding supported aqueous catalyst on unmodified silica. This implied that the oxidation catalysis occurred within the small surface supported surfactant assemblies as ‘nano-reactors’, whose controlled hydrophobic and hydrophilic affinities in this microenvironment significantly improved the mass transfer efficiency of reaction components.     

Hearing only one side of normal and mobile phone conversations

Mobile (cell) phone conversations are commonly perceived as annoying when conducted in a public space. An experiment is described that demonstrates one factor contributing to this phenomenon: hearing only one side of a conversation makes it more noticeable and intrusive. Two actors repeatedly staged the same conversation under three conditions: cell phone; normal, co-present both audible, and co-present only one audible. After the staged conversation, which took place on a train, a third person obtained verbal ratings from members of the travelling public. As in a previous experiment published in this journal, the cell phone conversation was rated as more noticeable and intrusive than the normal co-present both audible conversation. Critically, a new experimental condition, co-present one-audible, in which both actors were present but only one side of the conversation was heard, produced ratings equivalent to the cell phone condition. This 'need-to-listen' effect is discussed with regard to implications for design and theories of language use.     

The Response of CsI(Tl) to Energy Degraded Fission Fragments

The scintillation response of a CsI(Tl) crystal to energy degraded fission fragments derived from a 252Cf spontaneous fission source has been measured over the energy ranges 34-51 MeV (heavy fragment) and 42-74 MeV (light fragment). The response to ?-ray induced electrons and to ?-particles was also measured for comparison purposes. The results indicate that the scintillation response for these particles is a monotonically decreasing function of specific energy loss.