Synthesis
Water content of samples (e.g., solvents) is determined using Karl-Fisher titration (Mettler Toledo Titrator C20). The analyte solution is HydranalTM-Coulomat AG made by Honeywell Fluka and purchased through Fisher Scientific (prod # 15694490). The analyte solution includes methanol (CAS: 67-56-1), diethanolamine (CAS: 111-42-2), sulfur dioxide (CAS: 7446-09-5), imidazole (CAS: 288-32-4) and 1H-imidazole monohydriodide (CAS: 68007-08-9).
Karl Fischer Titration
A Glass Oven Kugelrohr (Buchi, B-585) is used for distillation, drying (037143 accessory), and sublimation (037133 accessory). It has a programmable 3-step temperature/time control setting options, the entire length of the oven tube heats up to a maximum of 300 °C, and the internal glass can be rotated at a speed of 0 – 50 rpm.
Kugelrohr
A Vacuum Atmospheres Solvent Purifier system (VAC 103991) removes water by circulating solvent using a pump through a solid-phase desiccant (Part number: 105643, 105644, 105646, 105649, 105652, 105655, and105653) housed in stainless-steel cartridges. The solvent is then dispensed through either external 24/40 universal inlet adapters or directly into a Glovebox. Current solvents on the system include DMSO, DCM, DMF, ACN, Toluene, ether, and THF.
Solvent Purification System (SPS)
The lab has two VAC OMNI-LAB gloveboxes for air and water free chemistry. Both gloveboxes are under a nitrogen atmosphere with oxygen levels kept below 5 ppm and water below 0.5 ppm. Oxygen levels are monitored using an electrolytic fuel cell sensor (VAC 102237) and water levels with Aluminum oxide probe (VAC 108669). Solvent removal is facilitated with activated carbon (VAC 102287). Each box is equipped with a -35°C freezer (VAC 100595). Antechambers for sample transfer use an Edwards RV12 A65514906 rotary vane pump (10 cfm at 60 Hz, ultimate pressure of 1.5x10-3 Torr). One glovebox is connected to a solvent purification system (VAC 103991), which enables delivery of dry solvents directly into the box.
Gloveboxes
The PolyScience Circulating Bath (AP15R-40) can control temperature from -40o to 200o C. The reservoir capacity is 15 liters. The circulating liquid is the also the product of PolyScience (polycool MIX-25),temperature range: -25° to 80° C.
PolyScience Circulating Bath (AP15R-40)
Photochemical reactions are accomplished on a Rayonet RPR-200 photoreactor from Southern New England Ultraviolet Company (SNEUCO). The reactor is equipped with (16) low-pressure mercury 14 watt light sources, centered at 253.7 nm (SNEUCO, Cat #: RPR-2347A). The intensity at the center of the reactor is reported by SNEUCO as 12.8 mW/cm2 at a reactor temperature of 44 ℃. The reactor is outfitted with a built-in fan (SNEUCO, Cat # CoolingFan) and magnetic stir-plate (IKA, Cat # 0003671000). A set of (16) LED lamps centered at 400 nm are also available for reactions.
Rayonet Photoreactor
Ultraviolet irradiation of samples is accomplished using a Boekel Scientific UV Crosslinker (Model 234100) equipped with 5 x 368 nm bulbs, having a power of ~5 mW/cm2 at the center of the sample chamber.
UV Box
A custom photoreactor was designed using Solidworks and manufactured by the UT chemical engineering machine shop. The aluminum chamber is hollow and connected to a circulator bath (Polyscience) to control temperature within a range from ~-30 to 100 °C. The photoreactor chamber holds 4 mL vials that sit above a single lens-focused LED (Rapid LED, Opulent). An LED controller (SLC-MA from Mightex Systems) is used to control the LED intensity. Available LEDs include UV (365 nm), blue (440-455 nm), and green (520-535 nm) with approximate light intensity ranges from 5 to 100 mW/cm2.
Circulating Photoreactor
The Monoprinter LightBox provides variable intensity blue light (~456 nm) from an array of 3W COB LEDs with a 15-degree lenses (diameter: 13mm). The LightBox is powered by an internal 24V 350W internal power supply. The intensity is regulated by PWM which varies from 0-255 PWM. Intensity with the diffuser installed can be estimated from the following equation Intensity = 0.8753 * (PWM value) - 2.7267.
