Immersion Reactors
A variety of Immersion Well Photochemical Reactors are available for the synthetic photochemist engaged in synthesis employing halogenation, exidation, or degradation methods. The reactors are designed to be efficient and include provision for irradiation by low or medium pressure mercury lamps. Double-walled immersion wells (in quartz or borosilicate glass) permit water cooling of lamps or filtering of excitation radiation. Various reaction flasks enable irradiations to be conducted under anaerobic conditions at low or constant temperature.


Low pressure mercury lamps emit over 90% of their energy at 254nm providing a useful source of ultra-violet radiation for photo reactions. Medium pressure mercury lamps have much more intense arcs and radiate predominantly 365-366nm light with smaller amounts in the ultra-violet region at 265, 297, 303 and 313 nm as well as significant amounts in the visible region at 404-408, 546 and 577-579nm. The choice of lamp power and lamp is determined to some extent by the nature of the photoreaction and volume of reactant solution.

Low pressure Mercury Vapour Lamp:

Nominal Wattage Diameter in mm Lamp Model Power Supply Model
6 14 MVL 1 MVL 11
12 26 MVL 2 MVL 21

Medium Pressure Mercury Vapour Lamp:

Nominal Wattage Diameter in mm Lamp Model Power Supply Model
125 20 MVL 3 MVL 31
400 22 MVL 4 MVL 41
Arc sources possess negative voltage-current characteristics, i.e. the voltage drop across the lamp decreases as the current through the lamp increases and conventional low-impedance power supplies cannot be used. Lamps must be operated from reactive type supplies having a large resistance or inductance in series to provide extra power to initiate the arc and reduced power for continuous operation.


These are double-walled wells, made in Quartz or Borosilicate Glass, which house the lamp. Inlet and outlet tubes provide for air or water cooling. A small diameter inlet tube extends to the bottom of the annular space to allow coolant flow from the bottom of the well upwards. A 2-3mm spacing between the walls allows filtering of certain wavelengths (with liquids, e.g.cobalt, nickel or copper sulphate solutions or with gases, e.g.chlorine) to reduce secondary photochemical reactions of products. Note that borosilicate glass does not transmit 254nm radiation.

Immersion Well Dimensions:

Overall Length (mm) Outside Diameter (mm) Joint Quartz Well Borosilicate Well
265 38 45/50 QW1 BW1
390 64 70/60 QW2 BW2

Reaction Flasks:

Two types of outer reaction flasks are available. All are made of borosilicate glass and are fitted with one central ground socket (to take an immersion-well) and other smaller sockets for a reflux condenser or dropping funnel, sampling port etc. Flasks may be supported by conventional laboratory stands and clamps.
Immersion Reactors

Standard Flask (Type A):

Cylindrical flask with flattened bottom for magnetic stirrer bar. Provided with one angle socket and one vertical socket. (PTFE tubing for gaseous agitation may be fed through the socket). Suitable for low/constant temperature irradiation.

Gas Inlet Flask (Type B):

As standard flask with additional sintered glass disc (dedium porosity) fitted to bottom of flask to permit gas agitation and allow the reaction mixture to be kept under an inert or reactive atmosphere. A glass PTFE stopcock is attached.

Reaction Flask Dimensions:

Reactant Capacity Nominal (mm) Length (mm) Joint Flask Type Model
A Std B Gas Inlet
150 215 45/40 * A/150
200 310 70/60 * A/250
150 315 45/40 * B/150
200 400 70/60 * B/200
400 400 70/60 * B/400

Reflux Condenser:

A double surface reflux condenser, prevents `creep' and loss of vapour when low boiling point liquids are used. Will fit all types of reaction flasks. Model RC1.

Complete Immersion Well Reactors:

The following table describes the various Immersion Well Reactors and which are supplied complete with Reflux Condenser.
Lamp/Power Supply 6 W 125 W 12 W 400 W
Immersion Well QW1 BW1 QW2 BW2
Reaction Flask B/150 B/150 B/200 B/200
Note: Full details of liquid cut-off solutions are supplied with the instruction manual.