Photoisomerization of ethyl ferulate: A solution phase transient absorption study

The role of symmetric functionalisation on photoisomerisation of a UV commercial chemical filter

“…Several reports have suggested the presence of 1 np* states playing a role within relaxation of similar systems. 8,28,45 Fluorescence has also been reported for similar systems 7,20,46 and was again observed here with the quantum yield reported as 0.039 AE 0.002 in cyclohexane (see ESI, † Fig. S17), hence a relatively minor pathway.…”

“…This latter step leads to effective repopulation of the ground (S 0 ) state. Previous reports of photoisomerisation, 7,15,18,20,42,43 have identified the presence of an absorption feature at long time delays, attributed to the formation of the corresponding geometric isomer; in the present case, this would correspond to E,Z-DPD (or Z,Z-DPD). This may be the case here, evidenced through the incomplete ground state bleach recovery of E,E-DPD (negative feature o350 nm; see Fig.…”

“…Coupled to this is the rapid relaxation of the excited state through an accessible conical intersection, consistent with the previous literature of similar species. 7,42,43 Furthermore, the apparent degradation upon constant UVR is attributed to interconversion to the E,Z-DPD isomer. This finding is, once again, in good agreement with previous reports on E-EHMC versus Z-EHMC.…”

“…[1][2][3][4][5] Chemical filters, found in commercial formulations, have been designed to allay such overexposure. 6 Chemical filters based on cinnamates 7,8 are currently being used as a class of UVR absorbing molecules in commercial formulations due to their strong absorption of UVR and potent antioxidant properties. [9][10][11][12] Investigations into their photochemistry has shown a photoisomerisation pathway as a main route of deactivation, irrespective of solvent environment, [13][14][15][16][17] and starting geometric isomer (either E or Z); 14,18 although a change in lifetimes is noted.…”

Catalytic alcoholysis of alkaline extracted lignin for the production of aromatic esters over SO42−/ZrO2-ATP

“…The contents of aromatic esters increased steeply and a 22.5% selectivity was obtained for ethyl ferulate (ethyl 4-hydroxy-3-methoxycinnamate, compound 10, peak at 38.103 0 ), which is a noteworthy compound, not only because of its avor characteristics but also its antioxidant and functional properties and is currently used as a sun screening agent in commercial sunscreen blends. 33,34 Much larger amounts of aromatic esters were produced by the addition of SO 4 2À /ZrO 2 -ATP, suggesting that the depolymerization reaction of AEL appeared directional conversion over SO 4 2À /ZrO 2 -ATP. This can be attributed to the enhancement of porosity and the excellent properties for the selective hydrogenation of the acidied ATPsupported catalyst.…”