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  • Author: Edyta Makuch x
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Abstract

The synthesis of Ti-MCM-41 catalyst was performed. The obtained catalyst was characterized by the following instrumental methods: UV-vis, IR spectroscopy, XRD, and X-ray microanalysis. The activity of the obtained catalyst was tested in the process of allyl alcohol epoxidation with 30 wt.% hydrogen peroxide in methanol as a solvent and under atmospheric pressure. In the next stage, recovery of Ti-MCM-41 catalyst from the post-reaction mixture and its regeneration by washing with appropriate solvents and drying were conducted. In the case of total loss of the activity of the catalyst, calcination of the catalyst was also carried out. The loss of titanium from the structure of Ti-MCM-41 catalyst and a partial collapsing of the structure of this catalyst can be the main reason of the decrease the activity of the catalyst what was manly visible in the decrease of the values of two functions of this process: the allyl alcohol conversion and conversion of hydrogen peroxide to organic compounds.

Abstract

This work presents the studies on the oxidation of limonene with hydrogen peroxide and tert-butyl hydroperoxide (TBHP) in the presence of : TS-2, Ti-Beta, Ti-MCM-41 and Ti-MWW catalysts, at the autogenic pressure and atmospheric pressure. The examination were performed at the following conditions: the temperature of 140°C (studies in the autoclave) and 80°C (studies in glass reactor), the molar ratio of limonene/oxidant (H2O2 or WNTB) = 1:1, the methanol concentration 80 wt%, the catalyst content 3 wt%, the reaction time 3 h and the intensity of stirring 500 rpm. The analysis of the results showed that in process not only 1,2-epoxylimonene was formed but also: 1,2-epoxylimonene diol, carveol, carvone and perillyl alcohol but for 1,2-epoxylimonene obtaining the better method was the method at the autogenic pressure and in the presence of TBHP.

Abstract

The paper presents the oxidation of natural limonene (extracted from waste orange peels) by 60 wt% hydrogen peroxide, in the presence of Ti-MCM-41 catalyst and in methanol as the solvent. The aim of the research was to develop the most favorable technological parameters for the process of limonene oxidation (temperature, molar ratio of limonene to hydrogen peroxide, methanol concentration, Ti-MCM-41 catalyst content and reaction time) by analyzing changes in the main functions describing this process: the conversion of limonene, selectivities of appropriate products, the conversion of hydrogen peroxide and the effective conversion of hydrogen peroxide. The process is environmentally friendly process and it uses renewable raw material - limonene and a safe oxidant -hydrogen peroxide. During the study, very valuable oxygenated derivatives of limonene were obtained: 1,2-epoxylimonene, its diol, carvone, carveol, and perillyl alcohol. These compounds are used in medicine, cosmetics, perfumery, food and polymers industries.

Abstract

This work presents the studies on the optimization the process of allyl alcohol epoxidation over the Ti-SBA-15 catalyst. The optimization was carried out in an aqueous medium, wherein water was introduced into the reaction medium with an oxidizing agent (30 wt% aqueous solution of hydrogen peroxide) and it was formed in the reaction medium during the processes. The main investigated technological parameters were: the temperature, the molar ratio of allyl alcohol/hydrogen peroxide, the catalyst content and the reaction time. The main functions the process were: the selectivity of transformation to glycidol in relation to allyl alcohol consumed, the selectivity of transformation to diglycidyl ether in relation to allyl alcohol consumed, the conversion of allyl alcohol and the selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed. The analysis of the layer drawings showed that in water solution it is best to conduct allyl alcohol epoxidation in direction of glycidol (selectivity of glycidol 54 mol%) at: the temperature of 10–17°C, the molar ratio of reactants 0.5–1.9, the catalyst content 2.9–4.0 wt%, the reaction time 2.7–3.0 h and in direction of diglycidyl ether (selectivity of diglycidyl ether 16 mol%) at: the temperature of 18–33°C, the molar ratio of reactants 0.9–1.65, the catalyst content 2.0–3.4 wt%, the reaction time 1.7–2.6 h. The presented method allows to obtain two very valuable intermediates for the organic industry.

Abstract

In this work the studies on the antioxidative properties of extracts from various morphotic parts of the ground elder (leaves, rhizomes, seeds and flowers) were presented. Moreover, the effect of different extraction methods (ultrasonic assisted extractions, extraction in a Soxhlet apparatus, extraction at the boiling point of the solvent used), solvent and its amount, and extraction time on the antioxidative properties of the obtained extracts were tested. The studies showed that all parts of ground elder can show radical scavenging activity, and it depends mainly on the method of extraction and extraction time. But the most beneficial is ultrasonic assisted extraction which used lower amount of solvent (ethanol). In case of all parts of the ground elder (leaves, rhizomes, seeds and flowers) it allows to obtain very high values of the antioxidant capacity (above 90%) for very short extraction time amounted to 20–40 minutes.