An efficient and environmentally friendly process for artemisinin extraction using monoether as the solvent under ultrasonic irradiation has been developed.

A series of carbon-based materials were illustrated to be efficient additives to improve the product distribution of isobutane/butene alkylation catalyzed by H 2 SO 4 . Among the tested materials, graphene oxide (GO) was shown to be the most efficient additive. With the presence of trace amounts (e.g., 0.1 wt %) of GO sheet, the weight percentage of C8 in the product could increase by ∼11% and research octane number (RON) of the alkylate was enhanced by ∼2. The presence of GO in H 2 SO 4 led to no obvious change of the acidity. The improved product distribution could be attributed to the enhanced emulsification and better dispersion of the reactants in the acid. The lifetime of the catalytic system was extended from 110 times (with no additive) to 140 times, as the formation of acid soluble oil was inhibited when the additive was present. This efficient and environmentally benign emulsifier could be a particularly promising additive for the current alkylation process catalyzed by H 2 SO 4 .

Poly­(ethylene glycol) (PEG), a kind of “green” medium, was used to extract artemisinin from the Chinese herb Artemisia annua L. to replace the traditional volatile and explosive solvents like petroleum ether, diethyl ether, etc. PEGs, with different molecular weights, show excellent ability for artemisinin extraction, and the extraction efficiency decreased with the increase of molecular weight. It was also demonstrated that ultrasonic irradiation could further enhance extraction efficiency compared with conventional water bath heating. Results indicate that the extraction amount of artemisinin from one gram of the leaves could reach 15.8 mg/g under the optimal conditions with ultrasonic power of 100 W, the temperature of 50 °C, time of 1 h in PEG-200, which were optimized by response surface method. Compared with Soxhlet extraction using petroleum ether (PE), the method developed here shows higher extraction efficiency (15.8 mg/g for PEG vs. 14.9 mg/g for PE process) and shorter extraction time (1 h vs. ca. 12 h). Additionally, artemisinin in the PEG solution can be recovered using resin adsorber. The results show that the recovery of artemisinin could reach almost 100% by D101 or H103 porous resin, and then the drug could be desorbed from the resin by ethanol or ethyl acetate. Moreover, the kinetic and mechanism studies of the extraction process revealed that ultrasonic irradiation could enhance mass transfer and the hydrogen bonding interactions between artemisinin and PEG further facilitate the separation of artemisinin from the leaves. This work provides an alternative process for efficient artemisinin extraction by using an environmentally benign medium with outfield intensification, which could be potentially extended to the production of other natural drugs.