## 2 Applications in Chemistry  
### Decarboxylation of Cyclic Carbonates  
The decarboxylation reaction of glycerol carbonate (GC) **1a** with concomitant generation of CO\({}_{2}\) is a typical method used to obtain the 1,2-anhydroglycerol derivative denominated glycidol, which has a variety of industrial uses, such as in surface coatings, as a gelation agent in solid propellants, as a stabilizer for natural oils and vinyl polymers, and as a demulsifier (emulsion breaker). Glycidol is also used as an intermediate in the synthesis of esters and amines and it can be of high-value in the production of epoxy resins, polyurethane, and in the controlled etherification of glycerol to form polyglycerols [22; 23]. At the industrial level, glycidol can be produced through oxidation of allyl alcohol using hydrogen peroxide in the presence of a titanium silicate catalyst [24]. However, all conventional processes used to prepare glycidol generate undesirable byproducts; therefore, producing glycidol from glycerol derivatives stands as an interesting alternative to minimize the generation of waste. [PERSON], [PERSON], and co-workers [25] performed the decarboxylation of GC **1a** to glycidol **2a** using various ionic liquids (ILs) as catalysts (0.5 mol%) at 175 \({}^{\circ}\)C under reduced pressure (2.67 kPa) for 30 min, releasing CO\({}_{2}\) as the only co-product (Scheme 1). After studying the catalytic efficiency of anions (with a range of sodium salts) and cations (with a range of metallic chlorides), the authors discovered that both the yield and selectivity in producing glycidol **2a** could be improved by using ILs. The best results were attained using [bmim] nitrate and iodide (59-73% yields), due to the strong interaction of the anion of the IL with **1a** and the weak interaction with **2a**. The effects of the \(N\)-cations were less pronounced, while [bdmim]NO\({}_{3}\), [bmim]NO\({}_{3}\), [Bu\({}_{4}\)N]NO\({}_{3}\), and [MPPyr]NO\({}_{3}\) all proved similarly satisfactory for the production of **2a**. The addition of Lewis acid \(Z\)n(NO\({}_{3}\))\({}_{2}\) to the reaction medium caused an increase in the glycidol yield, which was attributed to the weakening of the hydrogen-bonding interactions between the nitrate anion of [bmim]NO\({}_{3}\) and the hydroxyl groups of **1a** and **2a**. In a continuous process, a solvent was used to minimize the contact between the IL and glycidol while simultaneously removing **2a** as soon as it formed. The use of high-boiling solvents, such as glycol dimethyl ether, dibenzyl ether, and dibutyl phthalate, increased the yield (83-98%) and selectivity in both batch and continuous reactions. The mechanism of the decarboxylation of **1a** was theoretically investigated under [EMIm]NO\({}_{3}\) catalysis and computational calculations showed that the decarboxylation of **1a** to **2a** to proceeded in two steps: (1) nitrate-assisted ring-opening of **1a**, followed by formation of a 3-membered ring; (2) proton-transfer from HNO\({}_{3}\) to an oxygen atom of the carbonate group, along with the simultaneous loss of CO\({}_{2}\). It is worth mentioning that [PERSON] and co-workers [26] recently developed a similar protocol for synthesizing epoxybutane from 1,2-butanediol by using the ionic liquid 1-butyl-3-methylimidazolium bromide in batch or continuous processes. With a view to getting away from conventional heating, the conversion of **1a** to **2a** was studied through alternative methodologies: solvent-free thermal activation at 150 \({}^{\circ}\)C over 23 h (about 35% conversion yield), ultrasound activation at ca. 60 \({}^{\circ}\)C (44-48% conversion yield), and microwave activation in liquid phase at 150 \({}^{\circ}\)C over 30 min (48-71% conversion yield). In all cases, the authors used a ZSM-5 zeolite or a zinc oxide-supported nanoscaled cobalt oxide (RT-10 CoZn, 5 wt%) as catalysts (Scheme 2) [27]. In thermal activation, the ZSM-5 zeolite showed 100% selectivity for **2a**, while it did not exceed 60% with RT-10 CoZn.