Ethylbenzene Hydroperoxide Research Articles

Effect of the cationic surfactant cetyltrimethylammonium bromide on the decomposition of ethylbenzene hydroperoxide

Effect of the cationic surfactant cetyltrimethylammonium bromide on the decomposition of ethylbenzene hydroperoxide

КИНЕТИЧЕСКИЙ АНАЛИЗ ТЕХНОЛОГИЧЕСКИХ КРИТЕРИЕВ ЭФФЕКТИВНОСТИ ПРОЦЕССА ОКИСЛЕНИЯ ЭТИЛБЕНЗОЛА В ПРИСУТСТВИИ КОМПЛЕКСОВ ДИБЕНЗО-18-КРАУН-6 ЭФИРА С ХЛОРИДАМИ CA, SR, BA

A kinetic scheme is proposed that is common to the processes of ethylbenzene oxidation and ethylbenzene hydroperoxide decomposition in the presence of dibenzo-18-crown-6 ether complexes with Ca, Sr, and Ba chlorides. The scheme includes reactions of the formation of intermediate adducts from components of the reaction mixture and catalyst molecules, classical reactions of initiation, propagation and termination of the chain, reactions of initiation and propagation of the chain with the participation of intermediate adducts, and molecular reactions (includingthose with the participation of intermediate adducts).Basedonexperimentaldataandtheproposedscheme, akineticmodelwasmade.The kinetic model, written in the form of nonlinear differential equations according to the mass action law describes in time the rate of change of the concentrations of all components of reaction mixtures for ethylbenzene oxidation and ethylbenzene hydroperoxide decomposition in the presence of dibenzo-18-crown-6 ether complexes with Ca, Sr, Ba chlorides. As a result of solving the inverse kinetic problem using the zero-order direct search method, the values of reaction rate coefficients were found where the kinetic model reproduces the experimental values of the concentrations of all components of the reaction mixtures of the processes under consideration within the average relative error of 25%.As a result of the analysis based on the kinetic model, it was established that the conversion of ethylbenzene in the process of its oxidation is most affected by the reaction of ethylbenzene with the ethylbenzene peroxyl radical (target reaction).Using the kinetic model, the following was shown: 1) the values of the conversion of ethylbenzene, depending on the nature of the catalyst, line up in a row that corresponds to a number of values of the reaction rates of ethylbenzene with ethylbenzene peroxyl radical; 2) the model qualitatively reproduces the trend of selectivity changes when changing the catalyst.

Oxidation of Organic Compounds in Supercritical Fluid Conditions During Disposal of Industrial Waste Waters of Nizhnekamskneftekhim PJSC and Kazanorgsintez PJSC

The study performed on the supercritical aqueous oxidation of organic compounds in the water runoff of Nizhnekamskneftekhim PJSC, which was formed at the stage of epoxidation of propylene with ethylbenzene hydroperoxide during the joint production of propylene and styrene oxide, as well as run-off at PJSC "Kazanorginsez", when obtaining phenol and acetone from "Bisphenol-A" plant. The article studies a continuous operation mode on a flow reactor with induction heating (the drain from PJSC "Nizhnekamneftekhim") and periodic on coming from PJSC "Kazanorginsez". It was identified that close to complete oxidation in the presence of heterogeneous catalysts was achieved in a continuous mode at a temperature of 823 K and an excess of oxygen equal to 4.

Heterogeneous Catalytic and Non-Catalytic Supercritical Water Oxidation of Organic Pollutants in Industrial Wastewaters Effect of Operational Parameters

This work reports supercritical water oxidation (SCWO) of organic pollutants in industrial wastewater in the absence and presence of catalysts. To increase the efficiency of the oxidation process, the SCWO of organic compounds in industrial wastewater was performed in the presence of various iron- and manganese-containing heterogeneous catalysts (Fe-Ac, Fe-OH, and Mn-Al). The catalytic and non-catalytic SCWO of organic compounds in wastewater from PJSC “Nizhnekamskneftekhim”, generated from the epoxidation of propylene with ethylbenzene hydroperoxide in the process of producing propylene oxide and styrene (PO/SM), was performed. The effect of operational parameters (temperature, pressure, residence time, type of catalysts, oxygen excess ratio, etc.) on the efficiency of the process of oxidation of organic compounds in the wastewater was studied. SCWO was studied in a flow reactor with induction heating under different temperatures (between 673.15 and 873.15 K) and at a pressure of 22.5 MPa. The reaction time ranged from 1.8 to 4.83 min. Compressed air was used as an oxidizing agent (oxidant) with an oxidant ratio of two to four. A pseudo-first-order model expressed the kinetics of the SCWO processes, and the rate constants were evaluated. In the present work, in order to optimize the operation parameters of the SCWO process, we used the thermodynamic properties of near- and supercritical water by taking into account the asymmetric behavior of the liquid–vapor coexistence curve.

Ethylbenzene Hydroperoxide: An efficient oxidizing agent for diastereoselective synthesis of Spiroepoxy oxindoles

Ethylbenzene hydroperoxide (EBHP) has been studied for the epoxidation of oxindole chalcones with various inorganic bases and different solvent systems. 10 M solution of NaOH with EBHP in hexane furnished a high yield of spiro epoxy oxindoles in a short reaction time at room temperature. The reaction condition applicable to electron-deficient, electron-rich arylideneindolin-2-ones, heteroarylideneindolin-2-ones and alkylideneindolin-2-ones to yield the diastereoselective aryl/heteroaryl and alkyl spirooxiranes. Comparative studies amid peroxide reagents showed EBHP is the best in terms of diastereoselectivity, yield and reaction time. Isotope labelling experiment showed the participation of water molecules in this oxidation mechanism.

FEATURES OF KINETICS POLYMERIZATION OF METHYL METHACRYLATE INITIATED BY HYDROPEROXIDES -N, N-DIETHYLDITHIOCARBAMATES OF COPPER (II) SYSTEMS

Kinetic studies have shown that the use of systems based on secondary and tertiary hydroperoxides with N, N-diethyldithiocarbamate copper (II) can be used as effective sources of free radicals in the polymerization of methyl methacrylate in moderately low temperatures region (323–343 K). The introduction of an aromatic ring in molecules of hydroperoxides (ethylbenzene hydroperoxide and cumene hydroperoxide) increases the reactivity of the initiating system «hydroperoxide – complex» in comparison with tertiary butyl hydroperoxide. The shift of the gel effect to the region of high conversions during the polymerization of methyl methacrylate was noted. Such systems allow not only to accelerate the polymerization of the monomer, but also to conduct it in a controlled mode. H1 NMR spectroscopy showed that the formed polymers contained end dithiocarbamate fragments. Such groups are labile. It has been shown that the obtained and isolated in the presence of the initiating system tertiary hydroperoxide – N,N-diethyldithiocarbamate of copper(II) polymers are macroinitiators that can initiate a new portion of the monomer.

Impact of As-Prepared and Purifıed Multi-Walled Carbon Nanotubeson the Liquid-Phase Aerobic Oxidatıon of Hydrocarbons

The article presents simple kinetic approaches to study the effect of multi-walled carbon nanotubes (MWCNTs) additives on the aerobic oxidation of hydrocarbons and to propose real acceptable mechanisms of the process. The aerobic liquid phase low-temperature oxidation of ethylbenzene conducted in the presence of multi-walled carbon nanotubes has been used as a model pattern. Kinetic analysis established the catalytic action associated with the presence of the iron compounds in inner channels of MWCNTs. These compounds are identified as ferric carbides provoking decomposition of the ethylbenzene hydroperoxide and thereby suppressing the competitive route of alky-peroxide radicals addition to the nanocarbon cage. Thus the reaction finally proceeds in the autocatalytic mode.Contradictory conclusions on the effect of CNTs on the oxidation chain processes existing in the literature are associated with the lack of control over nature and content of metal impurities in channels of nanotubes.

Quantum Chemical Calculation of the Effects of H2O on Oxygen Functional Groups during Coal Spontaneous Combustion.

The effects of H2O on the low-temperature oxidation characteristics of coal have always been one of the keys in the research of coal spontaneous combustion, but most studies rely on experiments for macroscopic derivation, and theoretical researches at the microlevel are rarely mentioned. In this paper, phenylacetaldehyde, phenylethyl alcohol, phenylacetic acid, and ethylbenzene hydroperoxide were used as modeling compounds of coal molecules containing aldehyde (−CHO), alcohol hydroxyl (−OH), carboxyl (−COOH), and peroxide (−C–O–OH). The surface electrostatic potential (ESP), electron density of atoms in molecules (AIM), and reduced density gradient (RDG) of coal molecules were calculated by density functional theory (DFT), and the thermokinetic parameters of low-temperature oxidation of coal molecules with or without H2O were analyzed. The results show that the extreme positive and negative ESPs are located at the H and O atoms of oxygen functional groups (OFGs), respectively, which are the active sites for H2O adsorption. The AIM and RDG show that the phenylacetaldehyde···H2O complexes have two kinds of adsorption configurations with two and three hydrogen bonds, and that the phenylethyl alcohol···H2O complexes also have two kinds of adsorption configurations with one and three hydrogen bonds, and that both phenylacetic acid···H2O and ethylbenzene hydroperoxide···H2O only have one adsorption configuration, forming two and three hydrogen bonds, respectively. According to electron density ρ(r) and potential energy density V(r), the adsorption strength of H2O by four kinds of oxygen functional groups is ranked as −C–O–OH > −COOH > −OH > −CHO. The thermokinetic parameters show that H2O can increase the activation energy (ΔE) of the oxidation reactions of phenylacetaldehyde and phenylethyl alcohol, which can inhibit the reaction and decrease the activation energy (ΔE) of the oxidation reaction of phenylacetic acid and ethylbenzene hydroperoxide, which can promote the reactions.

Kinetics of One-Pot Regioselective Cohydrogenation of Styrene Oxide and Aryl Alkenes: A Step toward Sustainable Development of a Novel Integrated Process for 2-Phenylethanol Production

A strategy of one-pot regioselective cohydrogenation of styrene oxide (STOX) and aryl alkenes (styrene and alpha-methylstyrene) in the presence of aralkyl alcohols (1-phenylethanol and 2-phenyl-2-propanol) is proposed. It would help reduce capital and operational expenditure in the aralkyl hydroperoxide-based 2-phenylethanol (2PEA) manufacturing process. Reactions are performed in a stirred tank reactor in the presence of a 5% Pd/C catalyst. A range of operating conditions are proposed wherein STOX is converted to 2PEA, whereas the aryl alkenes are converted to their corresponding alkylbenzenes. Interestingly, the rate of hydrogenation of STOX is much slower than the rapid hydrogenation of the aryl alkenes. The kinetic model for the reaction is proposed based on the experimental data, and the associated parameters are estimated by nonlinear regression. The apparent activation energy for STOX hydrogenation over the range of operating conditions is calculated as 47.65 kJ mol–¹. The estimated kinetic parameters are apposite for the technocommercial feasibility study and subsequent scaling-up issues of the aralkyl hydroperoxide-based novel scheme of 2PEA production. Based on the observations, conceptual flowsheets for 2PEA manufacturing using cumene hydroperoxide and ethylbenzene hydroperoxide are also proposed.

Изучение молибденсодержащих растворов методами ИК спектроскопии

Molybdenum compounds are widely used as catalysts for various chemical reactions, such as: oxidation, epoxidation, hydrogenation, reduction, etc. In particular, molybdenum compounds are used as a catalyst in the epoxidation of propylene with ethylbenzene hydroperoxide during the joint production of styrene and propylene oxide introduced into the industry as part of PJSC "Nizhnekamskneftekhim". We are working to verify the possibility of using glycol solutions, oxygen-containing inorganic compounds of molybdenum, such as molybdenum acid (MK), molybdenum anhydride (MA) and ammonium paramolybdate (PMA) as an epoxidation reaction catalyst. In the initial molybdenum compounds used to prepare the catalyst solutions, molybdenum is in the hexavalent state. The temperature treatment of these compounds in coordinating solvents, glycols, leads to their partial depolymerization and reduction to Mo(VI). Moreover, the more coordinating the solvent, the deeper these processes are flowed. There are reports in the literature on the study of various molybdenum compounds in aqueous media and crystalline state by IR spectroscopy and Raman scattering. It was found that the dissolution of MA, MK, and PMA in monoethylene glycol (MEG) is associated with the formation in the solution of compounds Mo(V), Mo(VI) of various molecular composition in the form of monomers, dimers, tetramers, and also in the form of the main components of hept- and octamers and higher molecular weight compounds. As the temperature rises, initially larger monomers of the octa- and hepta-form type transform into monomers of lower aggregation. All established patterns are analyzed by the example of PMA solutions in MEG.

Synthesis of ethylbenzene and isopropylbenzene hydroperoxides in a homogeneous catalytic system N-hydroxyphthalimide-Fe(III) and application of the solutions in epoxidation of olefins

The catalytic system N-hydroxyphthalimide – Fe(III) salt was used for the first time in aerobic oxidation of alkylbenzenes to the corresponding hydroperoxides. Microquantities of Fe(асас)3 or Fe(benz)3 were shown to enhance the efficiency of N-hydroxyphthalimide as the radical catalyst; as a result, hydroperoxidation of ethylbenzene and isopropylbenzene occurs at a temperature of 90–100 and 60 °С, respectively, instead of 150–120 °С, which is a typical temperature range of noncatalytic synthesis. When conversion of the substrates is 10–20 %, selectivity to hydroperoxides is retained at a level of 90–95 %. A further successful testing of the obtained solutions in the MoO3/SiO2-catalyzed epoxidation of olefins without a preliminary removal of the catalytic system components demonstrates that such low-temperature synthesis of hydroperoxides is promising as the initial step in epoxidation of olefins.

Получение гликолята молибденила с использованием этанола в качестве высаливающего растворителя

The global production of propylene oxide is more than 8 million tons/year and is increasing by more than 5% annually. Almost all domestic propylene oxide (72 thousand tons/year) is produced at PJSC Nizhnekamskneftekhim (Russia) according to one of the variants of the Halcon process – epoxidation of propylene with ethylbenzene hydroperoxide (HPEB) in the presence of a molybdenum catalyst. One of the most important tasks arising in improving the process for the joint production of styrene and propylene oxide at PJSC Nizhnekamskneftekhim (Russia) is the search and development of new catalysts and catalytic systems, one of the stages of this process – the epoxidation of propylene with HPEB. The complex molybdenum catalyst used in the production of propylene oxide, having high activity and selectivity, has several disadvantages, namely: low dissolved molybdenum content, high consumption of ethylbenzene hydroperoxide for its production, and instability during storage. Thus, the problem of obtaining a catalyst with a higher content of dissolved molybdenum and increasing the stability of the catalytic complex, i.e. development of new catalytic systems with the best technological and technical and economic indicators. An analysis of the scientific and technical literature and patent publications showed that in the synthesis of a complex molybdenum catalyst, various molybdenum compounds of both organic and inorganic nature can be used. During the study, molybdenum-containing solutions based on ammonium paramolybdate and monoethylene glycol were tested, distillation distillation products prepared by distilling off excess monoethylene glycol by strengthening under vacuum. Molybdenyl glycolate was isolated by salting out with ethanol from a distillation bottoms product.

Mechanisms of the stabilization of a molybdenum epoxidation catalyst by nitrogen-containing compounds

Nitrogen-containing compounds have been studied as stabilizing additives for a complex molybdenum catalyst for propylene epoxidation with ethylbenzene hydroperoxide. Introducing the additives increases the half-life period by a factor of 10–14. The effective constants and rates of the decomposition of the catalytic complex in the presence of stabilizing agents have been calculated. Two possible mechanisms of the action of the nitrogen-containing additives have been suggested.

Immobilization of transition-metal hydroxamates on polystyrene resins: Effective biomimetic heterogeneous catalysts for aerobic oxidation of ethylbenzene

Salicylhydroxamic acid(SHA) was covalently grafted onto chloromethylated crosslinked polystyrene spheres(CMCPS) by the Friedel-Crafts alkylation reaction. The amount of SHA on CPS was found to be mainly dependent on the amount of Lewis acid(SnCl4) used and the reaction temperature. Under optimized conditions, the amount of SHA attached to CPS could reach up to 0.43 g/g CPS. Transition metal ions[Co(II), Cu(II), Fe(III) or Mn(II)] were then introduced into the resulting SHA-functionalized microspheres(SHA/CPS) through SHA-metal ion chelation. The obtained microspheres MSHA/CPS were explored as biomimetic catalysts for the aerobic oxidation of ethylbenzene(EB) to ethylbenzene hydroperoxide(EBHP). Among the four supported metal catalysts, FeSHA/CPS showed the highest catalytic activity and good reusability, indicating its great potential as an effective heterogeneous catalyst for the aerobic oxidation of hydrocarbons under mild conditions.

Preparation of a Novel Stationary Phase for Separation of Ethylbenzene Hydroperoxides

The novelty of this work is preparation of a special stationary phase for selective separation of hydroperoxides. This column can be used widely in the polymerization industries where a variety of initiators (mainly the hydroperoxides) are used. In this work, the ionic liquid-based silica particles were prepared and used as a novel stationary phase for separation of ethylbenzene hydroperoxides. The mobile phase of methanol/acetonitrile from 90:10 to 70:30 (v v−1) was used to separate three isomers of ethylbenzene hydroperoxide. A satisfactory linearity was obtained from 1.0 to 110.0 mg mL−1 (RSD <4.0 %). The stationary phase performed stably and produced reproducible results, highlighting its potential as a separation material.

Homogeneous Liquid-Phase Oxidation of Ethylbenzene to Acetophenone in Continuous Flow Mode

The oxidation of ethylbenzene with hydrogen peroxide and molecular oxygen catalyzed by cobalt and bromide ions in acetic acid as solvent was studied. The oxidation of ethylbenzene with hydrogen peroxide provided a mixture of ethylbenzene hydroperoxide, acetophenone, 1-phenylethanol, and 1-phenylethyl acetate. After rapid initial oxidation, the reaction rate decreased steadily so that full conversion of ethylbenzene and reaction intermediates to acetophenone could not be achieved. In contrast, no catalyst deactivation was observed for oxidations using atmospheric oxygen. Ethylbenzene was oxidized to acetophenone in 74% selectivity after a reaction time of 150 min at 80 °C. The reaction conditions were translated to a continuous flow process using a tubular gas–liquid reactor. At temperatures of 110 to 120 °C and an oxygen pressure of ∼12 bar, the reaction time necessary for complete oxidation of ethylbenzene was reduced to 6 to 7 min. The acetophenone was formed in 80 to 84% selectivity, and virtually pure...

Synthesis and characterization of homoleptic titanium bulky alkoxo complexes and their application in 1-octene epoxidation

A new series of titanium alkoxo complexes [Ti(OR)4] (1–8) have been synthesized by the alcoholysis reaction of Ti(OiPr)4 with the corresponding alcohol (ROH = Adamantanol, (1R,2S,5R)-(−)-menthol, 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose, (1R)-(−)-myrtenol, 1,2:5,6-Di-O-cyclohexylidene-α-D-glucofuranose, (1S-endo)-(−)-borneol and (−)-sclareol). These homoleptic alkoxo titanium (IV) complexes have been characterized by spectroscopic and electrochemical techniques. In addition, they have been tested in the epoxidation reaction of 1-octene with ethylbenzene hydroperoxide as oxidant; obtaining yields of up to 90% and selectivity values of 50%. The conversion profile of EBHP was found to depend on the amount of titanium and on the chemical environment of titanium sites.

Homogeneous Catalysis of Liquid-Phase Hydroperoxide Decomposition in Hydrocarbons

The autoxidation of jet fuel takes place via a complex free radical reaction mechanism that involves the decomposition of hydroperoxides.The liquid-phase, unimolecular decomposition of hydroperoxide has been isolated for experimental study. Three hydroperoxides relevant to jet fuel autoxidation, including cumene hydroperoxide (CHP), dodecane hydroperoxide (DHP), and ethylbenzene hydroperoxide (EBHP), were thermally decomposed separately and found to closely fit first-order behavior with respect to hydroperoxide concentration. The activation energy for liquid-phase thermolysis of these hydroperoxides was found to be significantly less than typical gas-phase values. Parameters affecting the rate of hydroperoxide decomposition, such as dissolved metal content, organic acids, and metal deactivator additive (MDA) were explored. Metal type was shown to be a significant factor affecting hydroperoxide decomposition rate, while naphthenic acids (NA) were shown to have little effect on the rate. However, when disso...

Degradation of phenylethyl hydroperoxide in the presence of styrene epoxide and p-toluenesulfonic acid in an acetonitrile solution

It was shown that phenylethyl (ethylbenzene) hydroperoxide (EBHP) decomposes in an acetonitrile solution in an argon atmosphere in the presence of a styrene epoxide (SE)-p-toluenesulfonic acid (TSA) binary system yielding acetophenone and methylphenylcarbinol in a molar ratio of 1: 1. The expression for the EBHP degradation rate v = k p[TSA]1[SE]0[EBHP]0 is equivalent to the relationships obtained earlier for the rates of oxygen uptake by the binary system and the buildup of the oxidation product. The temperature dependence of the specific rate of degradation is given by k p = 1 × 1014exp (−111.8 kJ mol−1/RT) s−1 (333–348 K).

Poly(propylene imine) dendrimer complexes as catalysts for oxidation of alkenes

Complexes of poly(propylene imine) dendrimers D8[DAB-dendr-(NH 2) 8] and D32 [DAB-dendr-(NH 2) 32] were prepared by interaction of the dendrimers with transition metal salts such as FeCl 3.6H 2O; CoCl 2.6H 2O; CuCl 2.2H 2O; VOSO 4.5H 2O; Na 2MoO 4.2H 2O and Na 2WO 4.2H 2O at room temperature in aqueous solutions. The content of metal ions in the complexes was found to be from 8.2 to 69.6 mg metal ion/g polymer carrier. The complexes were characterized by using IR, UV–VIS, Moessbauer spectroscopy and EPR. The anticipated co-ordination structure of the compounds was suggested. It was found that the order of the catalytic activity of the complexes of poly(propylene imine) dendrimers D8 and D32 in the reaction of epoxidation of cyclohexene with organic hydroperoxides such as tert-butyl hydroperoxide ( t-BHP), ethylbenzene hydroperoxide (EBHP) and cumene hydroperoxide (CHP) was as follows: D32-MoО 2 2+>D32-VО 2+>D32-WО 2 2+ > D32-Co 2+ > D32-Cu 2+>D32-Fe 3+. The order of reactivity of organic hydroperoxides in the reaction studied was: t-BHP > EBHP > CHP.