A new, Fe based, heterogeneous Lewis acid: Selective isomerization of α-pinene oxide

Solvent Influence on Selectivity in α-Pinene Oxide Isomerization Using MoO3-Modified Zeolite BETA

Natural source turpentine is an available source of α-pinene oxide. This compound’s value is especially given by the possibility of producing important compounds campholenic aldehyde and trans-carveol. In this work, we would like to present the usage of MoO3-modified zeolite BETA in α-pinene oxide isomerization concerning campholenic aldehyde and trans-carveol formation using a wide range of solvents. Catalyst calcination temperature also influenced the reaction course (selectivity to desired compounds and reaction rate). MoO3-zeolite BETA was prepared by the wet impregnation method and characterized by different techniques. The use of polar aprotic solvents had the most positive effect on the reaction course. Solvent basicity and polarity considerably influenced the reaction rate and selectivity to particular products. The combination of high basicity and the high polarity was the most suitable for the studied reaction from the reaction rate point of view. Selectivity to campholenic aldehyde and trans-carveol was the most influenced by solvent basicity. Higher solvent basicity caused the preferential formation of trans–carveol, influence on selectivity to campholenic aldehyde formation was the opposite. The described catalyst may be used for α-pinene oxide rearrangement to both desired products dependently on the used solvent. Molybdenum offers an exciting alternative for previously described modifications of zeolites for this reaction.

Phosphonate functionalized carbon spheres as Brønsted acid catalysts for the valorization of bio-renewable α-pinene oxide to trans-carveol

Herein, we report a simple route for the synthesis of phosphonate functionalized Brønsted solid acid carbon spheres as heterogeneous catalyst for the valorization of bio-derived α-pinene oxide. The Brønsted acidity was generated via two steps; hydrothermal carbonization of sugar to produce carbon microspheres followed by PCl₃ treatment to form phosphonate functionalized carbon. The presence of phosphonate was confirmed by CP-MAS ³¹P and ¹³C NMR. In addition, the presence of the P-C, O-P-C and HO-P[double bond, length as m-dash]O bonds of the phosphonate group was confirmed by FT-IR, ³¹P NMR, and XPS. SEM-EDAX analysis revealed the presence of a phosphorus content of ∼1.71 wt% on the surface of the catalyst while elemental mapping showed a uniform dispersion of phosphorus over the carbon spheres. The as-synthesized Brønsted solid acid catalyst was used for the isomerization of α-pinene oxide which gave 100% conversion with 67% trans-carveol selectivity in highly polar basic solvent in 1 h reaction time. Also, the catalyst showed good recyclable activity even after five cycles.

Highly selective synthesis of campholenic aldehyde over Ti-MWW catalysts by α-pinene oxide isomerization

Campholenic aldehyde is a highly valuable fine chemical that can be obtained by multistep synthesis from monoterpene α-pinene isolated from turpentine oil.

α-Pinene oxide isomerization: role of zeolite structure and acidity in the selective synthesis of campholenic aldehyde

The highest campholenic aldehyde yield (83%) achieved over MCM-22 is a result which rivals the best ones published so far.

Sc2(pydc)2 unit based 1D, 2D and 3D metal–organic frameworks as heterogeneous Lewis acid catalysts for cyanosilylation

Three new Sc-MOFs have been synthesized using H₂pydc linker and Sc(iii) ions. 1 features a ladder-shaped chain, 2 displays a waved layer and 3 exhibits a (3,3)-connected nbo-a network. All three compounds exhibit good catalytic abilities for the cyanosilylation of aldehyde.

Adrenal myelolipoma. 6 cases and a review of the literature

Adrenal myelolipoma is an uncommon, benign and hormonally inactive tumor. Most lesions are asymptomatic and usually are discovered incidentally at autopsy studies. Authors report on 6 patients (5 women, 1 man) with adrenal myelolipomas (5 right, 1 left), analyze their morphological findings and association with an adrenal hormonal overproduction. Five of the patients underwent surgery because of tumor size, in 3 of them histological evaluation confirmed myelolipoma and in 2 cases an adrenocortical adenoma with foci of myelolipoma. All the patients were asymptomatic and in 4 cases hormonal overproduction was not found. One female patient has oveproduction of dehydroepiandrosteron-sulphate (DHEAS) indicating a 3beta hydroxylase deficiency in this tumor and 1 patient has primary aldosteronism with a histological finding of an association of adrenocortical adenoma with foci of myelolipoma. Neither Cushings syndrome nor congenital adrenal hyperplasia were present in our group of patients.