Clinoptilolite as a natural, active zeolite catalyst for the chemical transformations of geraniol

Abstract

This work presented the studies with the natural zeolite—clinoptilolite as the catalyst for the isomerization of geraniol. During the research, it turned out that the studied process is much more complicated, and not only isomerization takes place in it, but also dehydration, oxidation, dimerization, cyclization and fragmentation of the carbon chain. Geraniol is an organic raw material which can be obtained not only by a chemical synthesis but also from plants (renewable biomass) by distillation or extraction method, for example a source of geraniol can be a plant—geranium. Before catalytic tests clinoptilolite was characterized by the instrumental methods, such as: XRD, porosity studies—nitrogen adsorption at 77 K, SEM, EDXRF, and FT-IR. Gas chromatography analyses showed that the main products of geraniol isomerization process were 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol. The selectivity of 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol depended on the temperature, catalyst content and reaction time. These parameters were changed in the following ranges: 80–150 °C (temperature), 5–15 wt% (catalyst content) and 15–1440 min. (reaction time). The most favorable conditions for 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol obtaining were: temperature 140 ºC, catalyst content 12.5 wt% and reaction time 180 min. At these conditions, the conversion of geraniol amounted to 98 mol%, and the selectivities of 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol amounted to 14 and 47 mol%, respectively.

Physicochemical study of natural zeolite modified with lavender essential oil

“…Clinoptilolite is regarded as the most important and plentiful natural zeolite. It is located in large deposits all around the world and is widely utilized on a global scale in different research together with essential oil delivery systems [1,2,3,4]. Zeolites, due to their heterogeneity, are substances that are easily isolated from the postreaction mixture, restored and reused in the process [4].…”

“…It is located in large deposits all around the world and is widely utilized on a global scale in different research together with essential oil delivery systems [1,2,3,4]. Zeolites, due to their heterogeneity, are substances that are easily isolated from the postreaction mixture, restored and reused in the process [4]. The crystal structure of clinoptilolite has open cavities in the form of tubules and cages.…”

Green method of conversion of geraniol to value-added products in the presence of selected minerals

“…Fajdek-Bieda et al studied the GA transformation process with the use of two natural zeolites: sepiolite 16 and clinoptilolite 17 . The tests assessed the infl uence of the following parameters: temperature (in the range from 80 to 150 o C), catalyst content (in the range from 5 to 15 wt%) as well as reaction time (in the range from 15 to 1440 minutes).…”

Preliminary Microbiological Tests of S-Carvone and Geraniol and Selected Derivatives of These Compounds That May Be Formed in the Processes of Isomerization and Oxidation

“…The process of isomerization of geraniol is a very complicated, as it also involves oxidation, dimerization, fragmentation, dehydration and cyclization [ 27 ]. Therefore, for studies involving creams, we decided to use only three derivatives of geraniol: two isomerization products (nerol and linalool) and one oxidation product (citral).…”