Edyta Makuch

The utilization of Ti-SBA-15 catalyst in the epoxidation of allylic alcohols

Ti-SBA-15, one of the latest titanium silicalite catalysts, has been prepared according to the literature by the direct hydrothermal synthesis using Pluronic 123 as structure-directing agent. The characterization of the catalyst was performed by means of the following methods: XRD, IR, UV–Vis, X-ray microanalysis and SEM. The catalytic properties of the Ti-SBA-15 catalyst have been tested in the epoxidation of allyl alcohol, methallyl alcohol, crotyl alcohol and 1-butene-3-ol with hydrogen peroxide. The process has been described by the following main functions: the selectivity to epoxide compound in relation to allylic compound consumed and the conversion of allylic compound.

Studies on the deactivation of Ti-MCM-41 catalyst in the process of allyl alcohol epoxidation

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.

Fe-carbon nanoreactors obtained from molasses as efficient catalysts for limonene oxidation

Abstract Fe-carbon nanoreactors were prepared by the impregnation of carbon cages with iron nitrate. Carbon cages were obtained using molasses as a carbon precursor and silica spheres as a template. The porous structure of the carbon cages allows for uniform dispersion of Fe. Fe concentration was equal to 0.68, 1.32, and 2.64 wt% as Fe3O4. Obtained materials were characterized by nitrogen adsorption at 77 K, X-ray powder diffraction (XRD), and scanning electron microscope (SEM) method. Fe-carbon nanoreactors were very active in limonene oxidation. Fe-carbon nanoreactors were used as a catalyst in limonene oxidation by t-butyl hydroperoxide.

The oxidation of limonene at raised pressure and over the various titanium-silicate catalysts

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.

Studies on Obtaining Diglycidyl Ether from Allyl-Glycidyl Ether over the Mesoporous Ti-SBA-15 Catalyst

The work presents the studies on the epoxidation of allyl-glycidyl ether (AGE) to digly‐ cidyl ether (DGE) over the mesoporous Ti-SBA-15 catalyst and with 60 wt% hydrogen peroxide. The influence of the following parameters was studied: the temperature 0– 100°C, the molar ratio of AGE/H2O2 = 0.03:1 – 4:1, the content of Ti-SBA-15 catalyst 0.0–0.5 wt%, and the reaction time 15–240 min. The studies showed that it is possible to obtain DGE with the selectivity of 100 mol% (for reaction time below 60 min) but at low conver‐ sion of AGE – about 4 mol%. The prolongation of the reaction time decreases the selectiv‐ ity of DGE because the following competitive reactions take place: (1) hydration of the epoxide ring in AGE and 3A12PD formation, (2) collapsing of the ethers by hydrolysis of the ether groups, and (3) the epoxidation and the hydration of the products of collapsing and obtaining glycerol. The explanation of the very high ineffective decomposition of hy‐ drogen peroxide and possible ways of increasing its efficiency of conversion are also pre‐ sented.

Hydroxylation of Phenol with Hydrogen Peroxide over the Ti-MWW Catalyst in the Presence of Acetonitrile

Abstract This work presents the results of phenol hydroxylation with hydrogen peroxide over the Ti-MWW catalyst. The studies were carried out under autogenic pressure and in the presence of acetonitrile as a solvent. The influence of the following technological parameters on the course of hydroxylation was examined: the temperature in the range of 100-150 °C, the molar ratio of phenol/H2O2 1:1-3:1, the acetonitrile (solvent) concentration in the range of 20-90 wt%, the catalyst Ti-MWW concentration in the range of 5-15 wt% in relation to phenol, reaction time in the range of 15-300 min. The main functions describing the process were: the selectivities of transformation to hydroquinone, pyrocatechol, and p-benzoquinone in relation to phenol consumed, the conversion of phenol to organic compounds (hydroquinone, pyrocatechol, p-benzoquinone), the total conversion of phenol and the total conversion of hydrogen peroxide. There have been presented some considerations about possible mechanisms of phenol hydroxylation over Ti-MWW catalyst in acetonitrile (aprotic solvent).

Epoxidation of natural limonene extracted from orange peels with hydrogen peroxide over Ti-MCM-41 catalyst

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.

The utilization of the mesoporous Ti-SBA-15 catalyst in the epoxidation of allyl alcohol to glycidol and diglycidyl ether in the water medium

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.