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Looking
for the Driest Solvents ?
Laboratory
techniques make regular use of anhydrous solvents, especially in analysis
and synthesis. But to purify and dispense them brings many difficulties.
To
address this need we have taken further the high purity concept of our
famous ROMIL-SpS Super Purity Solvents.
A range of specially dried solvents with such low water levels that
surpass even the so-called anhydrous offerings from rivals. In general
ROMIL Hi-Dry®
anhydrous solvents are specially produced to a water specification of less
than 50 ppm (<0.0050%). However, many solvents go well beyond that and
are routinely produced to lower than 5 ppm (<0.0005%).
Solvents
this dry need a packaging system designed to ensure that the exceptional
state of dryness achieved at time of purification is retained throughout
storage and use. Before filling, we first oven-dry the amber glass bottles
to remove all traces of water which may be present on the inner walls. At
such low levels even this trace moisture is noticeable. The bottles are
then filled under an inert atmosphere of dry nitrogen to prevent moisture
build-up and sealed with a special cap.
 Specially
designed both to retain solvent dryness and purity and to facilitate
dispensing, the Hi-Dry®
cap features a double seal; a PTFE wad and a self-sealing septum. The PTFE
wad sits between the solvent and the septum thereby maintaining the
original chemical purity and giving an extended shelf life before initial
use.
The
self-sealing septum allows the solvent to be dispensed by syringe at the
point of use but because the cap itself is screw-on it may also be opened
conventionally. However, it is important to note that once in contact with
the atmosphere product quality can deteriorate depending on the
hygroscopic nature of the solvent.
To
overcome this we recommend that dispensing operations are conducted under
dry nitrogen either in a dry cabinet or with a positive pressure of the
gas within the bottle. For safety reasons this should not exceed 0.3 bar
(0.31 kg/sq cm) and should only be undertaken by personnel trained in such
techniques and wearing appropriate safety equipment.
Hi-Dry
is a registered trademark of ROMIL Ltd.
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