2,5-Furandicarboxylic acid (FDCA) has received attention as an emerging bio-based building block with many applications, especially in renewable polyesters. The common route to FDCA uses the unstable 5-hydroxymethylfurfural (HMF) as...

Abstract:We report the first example of a tandem kinetic resolution/cycloisomerization of racemic allenic acetates in the presence of Burkholderia cepacia lipase (PS Amano SD) and catalytic amounts of chloroauric acid (HAuCl 4 ) which affords 2,5-dihydrofurans, as well as unreacted starting material, in one pot with high enantiomeric excess and moderate to good yield.

Crude sulphate turpentine (CST), containing α-pinene, 3-carene, other terpene isomers, and organic sulphur compounds, was used as feedstock in the production of cymenes with commercial zeolite catalysts. The catalysts used were not sensitive to sulphur, and the desulphurisation step was not needed prior to cymene synthesis. The experiments were performed in a continuous fixed bed reactor. Promising results were obtained after initial optimization at temperatures close to 300 °C with faujasite Y zeolite under 5 bar N 2 pressure. Cymenes were produced with 54% yields from model compound α-pinene and with 28% yields from CST. The mechanistic route of the reaction can be divided into three steps: (1) ring opening, (2) rearrangement, and (3) dehydrogenation. The final step in the formation of p-cymene can occur via dehydrogenation or disproportion; here the effect of reaction conditions and catalyst plays a crucial role. Article pubs.acs.org/OPRD

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The dehydrogenation of γ-terpinene was studied under catalyst-and solvent-free reaction conditions using air as an oxidant. The dehydrogenation affords p-cymene in good yields in a continuous flow reaction setup. The initial optimization of the reaction parameters showed that the dehydrogenation is highly dependent on the vapour/liquid phase equilibrium and the availability of oxygen in the vapour phase.Scheme 1