Lucent360™ Case Study:

Scaling Up: 100 mL reaction in the Lucent360™

The following reaction was performed at 100 mL scale (5 mmol) with the Lucent360™ batch reactor (HCK1021-01-007) at 450 nm equipped with nitrogen inlet/outlet ports, a septum for syringing in reagents/sampling and a temperature probe. (see photo above) The reaction is cooled by an external chiller set at 25 °C.  For scaling up the reaction, the concentration of the iridium catalyst was reduced by 10% from 1 mol % to 0.1 mol % from the corresponding 2 mL reaction.

Figure 1:

The 100 mL reaction was performed according to the following protocol (Table 1):

In the 700 mL Lucent 360 reactor, was added 54.9 mg Ni-glyme (5 mol %, 250 µmol), 67.1 mg dttbpy (5 mol %, 250 µmol) and 2.44 g Cs2CO3 (1.5 equiv., 7.5 mmol.  To the reactor was a 100 mL solution in DMSO containing 0.995 g bromoacetophenone (5 mmol) and 1.63 g Boc-Val-OH (1.5 equiv., 7.5 mmol).  5.61 mg Ir(dF-CF3-ppy)2(dtbbpy) (0.1 mol %, 5 µmol) was added as a 1 mL solution in DMSO.  The resulting solution was sparged with nitrogen for 15 minutes prior to turning on the LED’s and with a constant stream of nitrogen during the reaction.  The reaction was performed at 30 °C in the Lucent360™ with 5- 450 nm LED modules at 100% intensity.  Analytical samples were taken from each vial at 1,2 and 4 hours for analysis by LC-MS (10 µL dilution to 1 mL in DMSO.

At 1 hour, starting bromoacetophenone was completely consumed and 81% of the expected product was determined by LC-MS.

Reagent Equivalent Amount (µmol) Amount (mol) 0.001 M
bromoacetophenone 1 5000 0.005 995.20 mg
boc-Val-OH 1.5 7500 0.0075 1629.45 mg
Ir 0.001 5 0.000005 5.61 mg
“Ni” 0.05 250 0.00025 54.93 mg
dtbbpyp 0.05 250 0.00025 67.10 mg
Cs2CO3 1.5 7500 0.0075 2443.65 mg
solvent DMSO 0.05M 0.1 L

Actinometry experiments with 100 ml reaction in the Lucent360™ have determined an effective power of 40 W in the reactor.  This corresponds to a photon flux in the reactor at 150×10-6 einstein/s.  This value represents 150×10-6 moles of photons per second in the 100 mL reaction.

Based on our 81%, we estimated that 0.004 mol was produced in 60 minutes (3600 s) (1.13×10-6 mol/s) and the resulting quantum yield of the reaction would be 0.007.

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