he CEM Focused Microwave™ Synthesis System, Model Discover, is designed to enhance the ability to
perform chemical reactions under controlled conditions on a laboratory scale. The System facilitates either
homogeneous or heterogeneous solution phase chemistry, solid phase chemistry or chemistry conducted on
solid supports. It accommodates vessels ranging in volume from 5mL to 125mL for reactions performed
under atmospheric conditions and a 10mL vessel with septa for reactions performed at elevated temperatures
and pressures. Primary uses of the Discover are in the discovery and lead optimization phases of the
new product development process.
Microwave energy is applied to the vessel contents (reactants, catalysts, salts, solvents and/or solid
supports) to accelerate the chemical reaction. The microwave absorption properties of some liquid and
solid materials, due to their polar and ionic characteristics, have the capability to signifi cantly enhance
chemical reactions relative to traditional energy application (heating) techniques. The microwave interaction
properties with the reactants, intermediates, catalysts, solid supports and salts provide unique opportunities
for the synthetic chemist.
The Discover System consists of:
• A continuous microwave power delivery system with operator selectable power output from 0 - 300
watts (+/- 30 watts) programmable in 3-watt increments.
• A self-adjusting, single mode microwave cavity that is manually accessed via one of two attenuator
ports (both ports are included).
• A 4-line x 20-character vacuum fl uorescent display with alphanumeric keypad and on-board computer
for programming and operational control of the system. The memory will store and recall up
to 20 methods.
• 3 safety interlocks and an interlock monitoring system to prevent microwave emission when the
attenuator port is not properly installed.
• Two serial ports for computer interface and optional feature connections.
• An ethernet port for network connection (optional confi guration).
• An accessory kit.
Optional features include:
• Infrared Temperature Control System – This temperature control system uses a non-contact,
infrared sensor to measure temperature. It is located below the microwave cavity fl oor and measures
the temperature on the bottom of the vessel. The sensor is vessel volume independent and is used in a
feedback loop with the on-board computer to control the temperature rise rate and control point of the
vessel contents. Temperature is programmable from 25 - 250 oC.
• Fiber Optic Temperature Control System – This optional temperature control system, for use
with large volume, open vessel applications, uses a fi ber optic temperature probe for temperature
measurement and control of the vessel contents. This is an “invasive” measurement technique and
thus requires access to the reaction container from the external environment. It connects to the
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instrument through the second serial port at the rear of the instrument. When connected, the Discover
system automatically detects the temperature sensor and defaults to use this sensor for temperature
measurement and control. Temperature is programmable from 25 - 250 ºC.
• Direct Pressure Control System – This pressure control system uses a load cell for a direct pressure
measurement of the reaction vessel contents. The load cell is connected to a 10mL vessel via a
22-gauge needle, which penetrates just below the septum surface (the septum is positioned outside
the microwave fi eld.). The sensor provides very accurate low-end pressure measurements and is used
in a feedback control loop with the on-board controller to control the pressure rise rate and control
point of the vessel contents. Pressure is programmable from 0 – 300 psi (0 – 21 bar).
• Indirect Pressure Control System – This pressure control system uses a load cell for an indirect
measurement of the reaction vessel contents. The load cell is connected to a 10mL vessel and senses
changes in the external defl ection of the septa on top of the sealed pressure vessel. The sensor
housing incorporates a capture and release mechanism to secure the reaction in the cavity. Pressure
is programmable from 0 - 300 psi (0 - 21 bar).
CAUTION
The pressure control systems are usable only with CEM supplied 10mL reaction vessels
and septa.
• Stirring Option - The stirring option consists of a rotating magnetic plate located below the fl oor
of the microwave cavity. “Stirring” occurs when the rotating magnetic fi eld couples with a stir bar in
the vessel. The method setup enables the stirring feature. Standard stir bars or “fl eas” are used (not
included).
• Cooling Option – The cooling option consists of necessary valves and ports to direct a cooling gas
(either nitrogen or “clean” air) onto the vessel in the system cavity. This option will decrease the
temperature of a 2mL solution in a 10mL Pyrex reaction vessel from ~150 ºC to ~40 ºC in less than
120 seconds. Method setup enables the cooling feature. The gas is user supplied at a minimum
pressure level of 20 psi (~1.5 bar) and a fl ow rate of 25 liters/min