At 30 °C, in the presence of Amberlyst-15 as a catalyst, a tandem sequence was implemented by which a pool of innocuous reactants (isopropenyl acetate, acetic acid and acetone) allowed...

A new acid-catalyzed tandem sequence was investigated for the upgrading of renewable 1,2-diols such as propylene glycol (PG) and ethylene glycol (EG), with isopropenyl esters. For example, at 50 °C and in the presence of Amberlyst-15, the reaction of PG with nontoxic isopropenyl acetate allowed an initial irreversible monotransesterification of the diol, releasing acetone which then promoted acetalization on a second molecule of the glycol. The overall protocol was 100% carbon efficient, affording water as the sole byproduct. The reaction scope was extended to higher homologues of enol esters as isopropenyl-octanoate and phenylbutyrate. Additionally, the tandem sequence was successfully transferred in the continuous-flow (CF) mode where the catalyst (Amberlyst-15) could be used virtually indefinitely without loss of performance, and the solvent (THF or CPME) was quantitatively recovered and reused. Under CF conditions, the reaction of PG with isopropenyl acetate could be run at 30 °C and atmospheric pressure with a (nonoptimized) productivity up to 9.7 mmol g cat −1 h −1 , 3 times higher than that achieved in the batch mode. When ethylene glycol was used, a lower tandem selectivity was observed due to predominance of transesterification products, mono-and diesters, over the acetal compound.

Thermosetting polymeric materials have advantageous properties and are therefore used in numerous applications. In this study, it was hypothesized and ultimately shown that thermosets could be derived from comparably sustainable sub‐components. A two‐step procedure to produce a thermoset comprising of Kraft lignin (KL) and the cross‐linker adipic acid (AdA) was developed. The cross‐linking was activated by means of an acetylating agent comprising isopropenyl acetate (IPA) to form a cross‐linking mixture (CLM). The cross‐linking was confirmed by FTIR and solid‐state NMR spectroscopy, and the esterification reactions were further studied using model compounds. When the KL lignin was mixed with the CLM, partial esterification occurred to yield a homogeneous viscous liquid that could easily be poured into a mold, as the first step in the procedure. Without any additions, the mold was heated and the material transformed into a thermoset by reaction of the two carboxylic acid‐derivatives of AdA and KL in the second step.

CO 2 insertion reactions on terminal epoxides (styrene oxide, 1,2epoxyhexane and butyl glycidyl ether) were performed in a binary homogeneous mixture comprising NaBr as the nucleophilic catalyst and diethylene glycol (DEG) as both solvent and catalyst activator (cation coordinating agent). The reaction protocol was initially studied under batch conditions either in autoclaves and glass reactors: quantitative formation of the cyclic organic carbonate products (COCs) were achieved at T = 100°C and p 0 (CO 2 ) = 1-40 bar. The process was then transferred to continuous-flow (CF) mode. The effects of the reaction parameters (T, p(CO 2 ), catalyst loading, and flow rates) were studied using microfluidic reactors of capacities variable from 7.85 • 10 À 2 to 0.157 cm 3 . Albeit the CF reaction took place at T = 220°C and 120 bar, CF improved the productivity and allowed catalyst recycle through a semi-continuous extraction procedure. For the model case of 1,2-epoxyhexane, the (nonoptimized) rate of formation of the corresponding carbonate, 4butyl-1,3-dioxolan-2-one, was increased up to 27.6 mmol h À 1 equiv. À 1 , a value 2.5 higher than in the batch mode. Moreover, the NaBr/DEG mixture was reusable without loss of performance for at least 4 subsequent CF-tests.

An unprecedented two-step sequence was designed by combining batch and continuous flow (CF) protocols for the upgrading of two aminodiol regioisomers derived from glycerol, i.e., 3-amino-1,2-propanediol and 2-amino-1,3-propanediol (serinol). Under batch conditions, at 80–90 °C, both substrates were quantitatively converted into the corresponding amides through a catalyst-free N-acetylation reaction mediated by an innocuous enol ester as isopropenyl acetate (iPAc). Thereafter, at 30–100 °C and 1–10 atm, the amide derivatives underwent a selective CF-acetalisation in the presence of acetone and a solid acid catalyst, to afford the double-functionalized (amide-acetal) products.