Stefan Baj

Double bond migration in Sallyl systems catalysed by [RuClH(CO)(PPh3)3]

Abstract Reactions of S allyl systems (allyl sulphides of RSallyl type, where R=Et, allyl, Ph, Me 3 C, Ph 3 C, as well as of allyl phenyl sulphoxide, allyl phenyl sulphone, 2,5-dihydro-1,1-dioxothiophene) with [RuClH(CO)(PPh 3 ) 3 ] and other ruthenium compounds have been investigated. Double-bond migration was observed in the case of allyl trityl sulphide, allyl t -butyl sulphide and both sulphones, that is, where co-ordinating properties of sulphur were not too strong. High-yielded syntheses of ( E )- and ( Z )-RSCHCHCH 3 (R=Me 3 C, Z : E =96:4 and Ph 3 C, Z : E =92:8), ( E )PhS(O 2 )CHCHCH 3 and 2,3-dihydro-1,1-dioxothiophene from respective allyl systems are described. The binuclear Ru complex, formed in the model reaction of allyl phenyl sulphide with [RuClH(CO)(PPh 3 ) 3 ] has been isolated and its structure has been resolved. The mechanism of the reaction between S allyl systems and [RuClH(CO(PPh 3 ) 3 ] is proposed.

The Baeyer–Villiger oxidation of ketones with bis(trimethylsilyl) peroxide in the presence of ionic liquids as the solvent and catalyst

A new method for lactone synthesis with bis(trimethylsilyl) peroxide as the oxidant and ionic liquids as solvents is reported. We propose two possibilities for the Baeyer–Villiger reaction course. The first of these is based on simply exchanging dichloromethane, the classical solvent for Baeyer–Villiger oxidation, for the ionic liquid bmimNTf2, which results in increased product yields. The second possibility is the elimination of the Baeyer–Villiger reaction catalyst and use of 1-butyl-3-methylimidazolium trifluoromethanesulfonate as both the solvent and catalyst. This method gives lactones in high yields with the possibility of ionic liquid recycling.

A new method for dialkyl peroxides synthesis in ionic liquids as solvents

Organic hydroperoxides undergo smooth nucleophilic displacement reactions with alkyl bromides in the presence of 30% water solution of NaOH in several ionic liquids (ILs) at room temperature to afford the corresponding dialkyl peroxides in excellent yields under extremely mild conditions. Additionally, symmetrical dialkyl peroxides were obtained in ionic liquids as solvent with good yields.

Correlation Between the Chemical Structures of Dialkyl Peroxides and Their Retention in Reversed-Phase High-Performance Liquid Chromatography

Abstract High-performance liquid chromatographic capacity factors were determined on LiChrosorb RP 18 10 μm stationary phase for various organic peroxides. Studies of the quantitative structure-retention relationship (QSRR) employing non-empirical structural descriptors for the investigated compounds were performed by means of multiple regression analysts Semi-empirical methods MINDO/3, MNDO, AMI, PM3 were employed to determine the structural descriptors which may influence the retention in a reversed-phase chromatographic system. Informative values of non-empirical structural descriptors determined with various semi-empirical methods have been compared.

Useful Application of Acidic Ionic Liquids as Solvents in Baeyer–Villiger Oxidation with Hydrogen Peroxide for the Synthesis of Lactones

Abstract Cyclic ketones have been efficiently oxidized with hydrogen peroxide using acidic ionic liquids (ILs) as solvents. This is a new method for the synthesis of lactones with high yields that does not utilize any additional catalysts and enables ILs to be recycled.

Review: Advances in the Determination of Peroxides by Optical and Spectroscopic Methods

This review focuses on the recent advances made in the field of organic peroxide analysis using spectroscopic methods. In this area, optical techniques and mass spectroscopy play a dominant role. Emphasis has been given to peroxides of great practical significance, such as lipid hydroperoxides, antimalarial peroxides, peroxide-based explosives, and industrially relevant peroxides. The discussion includes current challenges and trends in each of these groups. The underlying chemical principles of the described methods are briefly discussed. All the advances are categorized by branches of spectroscopy, and example applications are outlined. The scope of this paper is restricted to the most significant advances published between 2003 and mid-2013.

Application of response surface methodology (RSM) to the optimization of a post-column luminol chemiluminescence analysis of silyl peroxides.

The possibility of the utilization of chemiluminescence post-column luminol oxidation (CL) in a HPLC system for silyl peroxides analysis has been investigated. The conditions of HPLC separation for 12 silyl peroxides, representing bissilyl and alkyl-silyl peroxides, as well as their potential impurities, were established. Optimal chemiluminescent post-column reaction conditions were found using central composite design (CCD) and response surface methodology (RSM). The interaction effects of four of the most important operating variables - the concentrations of luminol, hemin, sodium hydroxide and the post-column solution flow rate - on the light intensity were evaluated. The optimized conditions for analysis were the same for bissilyl and alkyl-silyl peroxides for the base concentration (0.03 M), the luminol concentration (0.4 g L(-1)) and the hemin concentration (0.3 g L(-1)). The only differences occurred in a reagent flow rate (for bissilyl peroxide -0.3 mL min(-1) and for alkyl-silyl peroxides -0.9 mL min(-1)). Under optimal conditions, the detection limits were in the 0.07-0.16 nM range for bissilyl, and 0.53-1.01 for alkyl-silyl peroxides. The calibration curves were linear in the 0.25-3 nM range for bissilyl and the 2.5-25 range for alkyl-silyl peroxides. Intra-day and inter-day precision was lower than 5.5% for each tested concentration level. A mechanism of luminol oxidation by silyl peroxides involving a hydrolysis step with the formation of hydrogen peroxide or hydroperoxide was proposed.

Study of the synthesis of mixed dialkyl peroxides from metal alkyl peroxide and alkyl halide by phase transfer catalysis

The kinetics of the reaction of the synthesis of selected mixed dialkyl peroxides from sodium and potassium organic peroxides in a two-phase solid/organic solvent system by phase transfer catalysis was studied. The effect of some parameters on the reaction rate was investigated. Pseudo-first-order kinetics can be used to describe the reaction rate. The apparent reaction rate constants were calculated and the activation energies of the reaction with different catalysts were determined.

Application of solid-liquid phase transfer catalysis system for peroxyester synthesis: A kinetic study of hydroperoxides acylation in the presence of solid sodium carbonate

Abstract In the research described below, we have developed a convenient and effective method of synthesis of organic peroxyesters to achieve 60–98% yields under extreme mild conditions. The study has been conducted on a model system using a reaction of acylation of 1-methyl-1-phenylethyl hydroperoxide (CHP) by means of butyryl chloride in the presence of solid Na 2 CO 3 and being performed under conditions of phase transfer catalysis (PTC). The effect of the following parameters on the reaction was tested: temperature, Na 2 CO 3 amount, catalyst structure and solvent polarity.

Absorption of carbon dioxide in aqueous solutions of imidazolium ionic liquids with carboxylate anions

The solubility of carbon dioxide at atmospheric pressure in aqueous mixtures of 1,3-alkyl substituted imidazolium ionic liquids (ILs) containing carboxylic anions was studied. The ILs showed increased solubility of CO2 with decreasing water concentration. The relationship between the CO2 concentration in solution and the mole fraction of water in the ILs describes a sigmoidal curve. The regression constants of a logistic function were used to quantitatively assess the absorbent capacity and the effect of water on CO2 absorption. ILs containing the most basic anions, such as pivalate, propionate and acetate, had the best properties. It was observed that the impact of water on absorption primarily depended on the cation structure. The best absorption performance was observed for 1,3-dibutylimidazolium pivalate and 1-butyl-3-methyl imidazolium acetate.