Synthesis of isobenzofuran derivatives from renewable 2-carene over halloysite nanotubes

AYu Sidorenko, AV Kravtsova, Päivi Mäki-Arvela, Atte Aho, Thomas Sandberg, IV Il'ina, NS Li-Zhulanov, DV Korchagina, KP Volcho, NF Salakhutdinov, Dmitry Murzin, VE Agabekov

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10 Citations (Scopus)


Condensation of a terpene 2-carene with 4-methoxybenzaldehyde over a range of acid aluminosilicates including halloysite nanotubes (HNT) was studied for as a model for preparation of isobenzofuran derivatives with a pharmaceutical potential. The catalysts were characterized by FTIR with pyridine, UV by adsorption of 2-phenylethylamine from the aqueous phase, SEM, TEM and N2 physisorption. The largest selectivity to the desired product (ca. 70%) over halloysite nanotubes is associated with weak acidity of these catalysts (45 μmol/g), allowing avoiding side isomerization and condensation reactions. Moreover, the highest yield on air-dry HNT clearly indicates that weak Brønsted sites favored the reaction. On the contrary, over strong Brønsted and Lewis acids (Amberlyst-15, scandium triflate), the yield of isobenzofurans did not exceed 16% with formation of mainly 2-carene isomerization products. DFT calculations showed that interactions of the aldehyde with cyclopropane moiety of 2-carene giving isobenzofurans are more beneficial than an alternative direct attack of a proton, leading to side reactions. A possibility to reuse of HNT catalyst was confirmed. Overall, halloysite is a highly effective catalyst for production of isobenzofuran compounds based on 2-carene.

Original languageEnglish
Article number110974
Pages (from-to)
JournalMolecular Catalysis
Publication statusPublished - Jul 2020
MoE publication typeA1 Journal article-refereed


  • Chemical Engineering


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