2.4 Continuous Flow Setup
The experimental setup used for micro-flow based photoisomerization and in-flow separation process is presented in supporting information (section S1). The solution is pumped from the inlet solution vessel using an HPLC pump (Knauer Azura P4.1S). The outlet stream from the pump is fed to FEP (fluorinated ethylenepropylene copolymer, IDEX 1548 L) capillary tubular reactor (ID 0.02”, OD 1/16”, length 5 m) which is wound around a cylindrical UV light source placed inside a closed oven. Irradiation is carried out using a low-pressure amalgam lamp (TS23-212; Dinies Technologies GmbH). The outlet then flows to the packed bed. The packed bed (stainless steel, ID 4.5 mm, L 25 mm) is packed with 200-220 mg of AgNO3 impregnated silica gel (as packing or adsorbent) with a mesh size of 230+ (Sigma-Aldrich). The AgNO3/silica particles are mixed with 1 mm borosilicate glass beads in a mass ratio 1.66:1 and then introduced to the packed bed with a funnel. The inert glass beads are applied to prevent particle agglomeration which results in channeling of the flow inside the packed bed (for more information on micropacked beds and the assembling process, we refer to [32]–[34]).The inlet and outlet of the packed bed have attached separately two frits with a pore size of 10 μm to keep the packing material inside the reactor. The outlet of the packed bed is recycled to the inlet solution vessel through a 0.2 m long FEP capillary tube. Samples are collected exactly before the recycle stream enters the inlet solution vessel. The inlet solution vessel is stirred with a magnetic stirrer bar to ensure a uniform concentration in the vessel. In a general micro-flow based photoisomerization and an in-flow separation experiment, cis -cyclooctene (0.06 g, 0.55 mmol), methyl benzoate as a singlet sensitizer (0.136 g, 1mmol) and n-dodecane as the internal standard for GC analysis (0.017g, 0.1 mmol) are dissolved in 25 ml n-hexane (with 1% diethyl ether) as solvent and mixed in the same vessel (volumetric flask of 50 ml) and from this vessel the solution is pumped to the flow setup.