Transformation of monoterpenes and monoterpenoids using gold-based heterogeneous catalysts

The History and Prospective of the AOPs for Environmental Applications in Colombia**

“…The Catalysis Group (Universidad Pedagógica y Tecnológica de Colombia, Tunja) has studied modified semiconductors applied to heterogeneous photocatalysis [88–93] . The Research Group in Photochemistry and Photobiology (GIFOC) and the Group of Environmental Catalysis [94,95] (Universidad del Atlántico) developed photochemical and photobiological processes. The CICAT group (UIS) studied the synthesis and evaluation of catalysts for environmental applications [96–103] .…”

Versatile Heterogeneous Catalytic System for the Selective Synthesis of Limonene Epoxide and Diepoxide

“…9,10 Limonene can be used directly in industrial applications such as aromas, cosmetics, additive foods, and cleaning materials, but it has also been extensively used as a precursor for the synthesis of high-added-value products based on oxygenated compounds such as epoxides, diepoxides, ketones, alcohols, aldehydes, and acids. 11 The oxidation route of limonene can occur toward two competitive pathways (Figure 1): (i) double bond epoxidation yielding limonene-1,2epoxide, limonene-8,9-epoxide, limonene diepoxide, and limonene glycol, and (ii) allylic oxidation yielding carveol, carvone, and perillyl alcohol; the predominance of each pathway depends on the oxidizing agent, the catalyst, and the reaction conditions. 12 Specifically, the catalytic epoxidation of monoterpenes has been a research hotspot in heterogeneous catalysis because epoxides are very useful intermediates or precursors in organic and pharmaceuticals synthesis, such as the production of compounds that exhibit antinociceptive and antitumoral activity.…”

Hydrogenation of citral and carvone on Pt and PtSn supported metallic catalysts. A comparative study on the regioselectivity and chemoselectivity

“…Among the valueadded products of these partial reduction processes are allylic alcohols, which are widely used in the pharmaceutical, cosmetic, and agrochemical industries, 3,4 and are typically obtained by chemoselective reduction of α,β-unsaturated aldehydes and ketones and also of more complex molecules derived from them. [5][6][7][8][9] It should be noted that several molecules used for this purpose (production of allylic alcohols) derive from the natural product family of the terpenes and commonly constitute essential oils, such as aldehydes or ketones, which have one or more CC olefin groups either isolated or conjugated to the CO carbonyl group. 8,10,11 In such cases, hydrogenation of one or two olefin groups leads to partially or fully saturated aldehydes and ketones, while hydrogenation of a conjugated carbonyl group produces allylic alcohols.…”

“…[5][6][7][8][9] It should be noted that several molecules used for this purpose (production of allylic alcohols) derive from the natural product family of the terpenes and commonly constitute essential oils, such as aldehydes or ketones, which have one or more CC olefin groups either isolated or conjugated to the CO carbonyl group. 8,10,11 In such cases, hydrogenation of one or two olefin groups leads to partially or fully saturated aldehydes and ketones, while hydrogenation of a conjugated carbonyl group produces allylic alcohols.…”

“…It should be noted that these systems have been more commonly used for the hydrogenation of α,β-unsaturated aldehydes, but the information on the hydrogenation of α,βunsaturated ketones with mono-or bimetallic-supported catalysts is sparse. 8,15,18,[35][36][37][38][39][40][41] In relation to the regioselective hydrogenation of the CC unsaturated groups, it must mention that the information is also scarce with supported metallic catalysts. Since a good regioselectivity is difficult to achieve with this type of catalysts, the use of catalysts based on metallic complexes is more common.…”