Stabilised liquid

The use of liquid oxygen difluoride (40 or 90%) to stabilise liquid ozone as oxidant for gaseous hydrogen in a rocket motor was not entirely successful, explosions occurring at both concentrations. 

Organic materials, particularly if fibrous with adsorbed or absorbed moisture present, may char or ignite in contact with the stabilised liquid form because of the very high heat of hydration (2.1 kJ/g) and formation of hot oleum which then functions as an oxidant. 

Dierking, I. Blenkhom,W. Credland,E. Drake,W. Kociuruha, R. Kayser, B. Michael, T. Stabilising liquid crystalline blue phases. Soft Matter 2012, 8, 4355-4362. 

A variety of sulphonation reagents can be used for the sulphonation reaction SOa/air from sulphur burning and subsequent conversion of the S02/air formed SOs/air from stabilised liquid SO3 or SO3 stripped from 65% oleum with dried process air, 20% oleum and chlorosulphonic acid. 

Stabilised liquid SO3 requires very precise temperature control and its residues, which contain noxious stabiliser residues after evaporation, are difficult to handle and dispose of. 

An alternative to sulphur burning and subsequent SO2 conversion to SO3 is the use of stabilised liquid SO3. The use of stabilised liquid SO3 is restricted by the proximity of a supplier. This chemical should be transported and handled with great care. A simplified flowsheet is presented in figure 14. The stabilised liquid SO3 is transferred by a membrane metering pump from the day tank through a filter and into the vaporiser. The gaseous SO3 thus obtain is filtered to remove any remaining mist and then mixed with dried process air (dewpoint -60 C) to the required SO3 level. 

There are, however, major disadvantages using stabilised liquid SO3 ... 

Figure 15 depicts a block diagram for SOa/air sulphonation based on stabilised liquid SO3. Figyie SO3... 

As theory has it, viscosity is responsible for stabilising liquid sheets and opposing any disturbances. This is clear from Fig. 15.41, where even at high injection pressures of 15 MPa, pure polyethylene glycol 6000 with a viscosity of ca. 500 mPa s produces a stable sheet, with thick rims at the end. Adding CO2 to the polymer at 5 MPa lowers its viscosity to nearly half of the atmospheric value. Small gas... 

Rajaram, C. Hudson, S. Effect of polymerisation temperature on the morphology and electrooptic properties of polymer-stabilised liquid crystals. Chemical Materials 1996,8,2451-2460. 

Table 5.1 gives the formulation of a polyethylene and a polystyrene used in some Uvitex OB extractability studies. In addition to the ultraviolet stabiliser, liquids obtained in extractability tests carried out on these plastics would contain various other substances, some of which are ultraviolet absorbers and which may be present in the extractant at higher concentrations than Uvitex OB. In this case the polymer also contained Santonox R, Wingstay T, phenolic antioxidant and styrene monomer. The presence of such ultraviolet absorbing substances in the extractant will interfere in the determination of Uvitex OB at 378 nm. In applying spectroscopic methods of analysis to extractants, consideration must always be given to the possibility of interference by any polymer additives present other than that which one is required to determine. 

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