Oxirane Ring Opening Reactions Research Articles

Rapeseed oil as feedstock for the polymeric materials via Michael addition reaction

Rapeseed oil was used to synthesize a Michael donor to obtain polymeric materials after nucleophilic polymerization via Michael reaction. Four different bio-polyols as precursors for the Michael donor monomer synthesis were synthesized from epoxidized rapeseed oil using an oxirane ring-opening reaction. Various alcohols such as methanol, butane-1,4-diol, 2,2′-oxydi(ethan-1-ol), and 2-ethyl-2-(hydroxymethyl)propane-1,3-diol were used to obtain bio-polyols with different OH group functionality. The transesterification reaction between the synthesised bio-polyol hydroxyl groups and tert-butyl acetoacetate ester introduced acetoacetate functional groups into their structure. The acid value, hydroxyl value, viscosity and moisture content of the synthesized polyols and corresponding acetoacetates were analyzed. Size-exclusion chromatography and Fourier transform infrared spectroscopy were used to study the chemical structure of polyols and acetoacetates. From developed acetoacetates and commercially available trimethylolpropane triacrylate, bio-based polymers were obtained via carbon-Michael reaction. The different chemical structures and functionalities of the synthesized bio-based monomers allowed for the development of polymer formulations with diverse cross-linking densities. The structural, physical and thermal properties of the developed polymers were analyzed using solid-state NMR, differential scanning calorimetry, dynamic mechanical analysis and thermal gravimetric analysis testing apparatus.

Synthesis and Frictional Characteristics of Bio-Based Lubricants Obtained from Fatty Acids of Castor Oil

The depletion of oil reserves and concerns about the environmental impact of the use and incorrect disposal of mineral lubricants have been promoting the development of bio-based lubricants. In this study, biolubricants obtained from fatty acids of castor oil were synthesized by esterification (>wt.%93), epoxidation (>wt.%92), and oxirane ring opening reactions using water (>wt.%92) or 2-ethylhexanol (>wt.%94) as nucleophilic agents. The frictional characteristics of the synthesized samples were obtained through tribological tests performed in a four-ball tester and compared with a commercial mineral oil. The sample obtained through oxirane ring opening with water showed the best frictional performance (FC = 0.0699 ± 0.0007) among the prepared samples, with equivalent wear rate (WSD = 281.2 ± 5.54 μm) and ca. 20% lower friction coefficient when compared to the commercial mineral oil, indicating its great potential for replacing mineral fossil oils.

In-Depth Kinetic Modeling and Chemical Analysis for the Epoxidation of Vegetable Oils in a Liquid–Liquid–Solid System

A heterogeneous catalyst for producing epoxidized vegetable oils, an important intermediate in the production of non-isocyanate polyurethanes, is essential for product separation and for decreasing the side-reaction, i.e., ring-opening reaction, via the Prileschajew method. The development of reliable kinetic models considering key variables for both phases and the mass transfer phenomena is missing in the literature. The reaction pathway for the ring-opening reaction is also under debate. Therefore, we studied the kinetics of epoxidation of cottonseed oil by perpropionic acid over the solid acid catalyst amberlite IR-120. An in-depth kinetic model was developed by using Bayesian inference. The reaction pathway for the ring opening was investigated. Propionic acid, a weak acid, allows for a decrease in the oxirane ring-opening side reaction.

The Synthesis of Bio-Based Michael Donors from Tall Oil Fatty Acids for Polymer Development

In this study, the synthesis of a Michael donor compound from cellulose production by-products—tall oil fatty acids—was developed. The developed Michael donor compounds can be further used to obtain polymeric materials after nucleophilic polymerization through the Michael reaction. It can be a promising alternative method for conventional polyurethane materials, and the Michael addition polymerization reaction takes place under milder conditions than non-isocyanate polyurethane production technology, which requires high pressure, high temperature and a long reaction time. Different polyols, the precursors for Michael donor components, were synthesized from epoxidized tall oil fatty acids by an oxirane ring-opening and esterification reaction with different alcohols (trimethylolpropane and 1,4-butanediol). The addition of functional groups necessary for the Michael reaction was carried out by a transesterification reaction of polyol hydroxyl groups with tert-butyl acetoacetate ester. The following properties of the developed polyols and their acetoacetates were analyzed: hydroxyl value, acid value, moisture content and viscosity. The chemical structure was analyzed using Fourier transform infrared spectroscopy, gel permeation chromatography, size-exclusion chromatography and nuclear magnetic resonance. Matrix-assisted laser desorption/ionization analysis was used for structure identification for this type of acetoacetate for the first time.

Amination of epoxides as a convenient approach for lipophilic polyamines synthesis

Objectives. Alkylated derivatives of polyamines are able to block the growth of cancer cells due to their embedding into the polyamine biosynthesis mechanisms. The study aimed to synthesize lipophilic derivatives of norspermine or triethylenetetramine based on the formation of a C–N bond during the opening of the oxirane ring by primary amines to expand a number of synthetic polyamine derivatives with antitumor activity.Methods. The starting compounds—glycidol alcoholate or epichlorohydrin—were reacted with hexadecyl bromide or sodium hexadecanolate to give glycidyl hexadecyl ether. The key reaction for the preparation of lipophilic polyamines was the amination of lipophilic epoxides with polyamines in the presence of calcium triflate. Acylation of the hydroxyl group formed during the opening of oxirane was carried out by the action of 4-dimethylaminopyridine and acetic anhydride. The introduction of an alkyl substituent in the presence of sodium hydride led to intramolecular cyclization with the formation of an oxoazolidine cycle. The regioselectivity of the oxirane ring opening reaction at the C(1) position of glycerol was confirmed by two-dimensional heteronuclear {1H,13C} nuclear magnetic resonance spectroscopy.Results. An approach to the synthesis of novel lipophilic polyamines based on the catalytic amination of epoxides was developed and tested. Compounds based on norspermine and triethylentetramine containing a hydroxyl group at the C(2) atom of the glycerin backbone were obtained. For norspermine derivatives, the hydroxyl group was modified: an acetyl substituent was introduced and a derivative containing an oxoazolidine cycle was obtained.Conclusions. The obtained lipophilic polyamines can be considered as potential antitumor agents, for which cytotoxicity against various cancer cells will be evaluated in the future.

Synthesis of Jatropha-Oil-Based Polyester Polyol as Sustainable Biobased Material for Waterborne Polyurethane Dispersion.

The utilization of vegetable oil in the production of polymeric material has gained interest due to its proven ability to replace nonrenewable petroleum sources, as it is readily modified via chemical reaction to produce polyol and subsequently for polyurethane production. Jatropha oil (JO), a second-generation feedstock, is one of the suitable candidates for polyester polyol synthesis because it contains a high percentage of unsaturated fatty acids. In this study, jatropha-based polyester polyols (JOLs) with different hydroxyl values were successfully synthesized via a two-step method: epoxidation followed by oxirane ring-opening reaction. Ring-opening reagents; methanol, ethanol, and isopropanol were used to produce polyol with hydroxyl number of 166, 180, and 189 mg/KOH, respectively. All the synthesized JOLs exhibited a Newtonian to shear thinning behavior in the measured shear rate ranges from 10 to 1000 s−1 at 25 °C. The viscosity of a JOL ring-opened with methanol, isopropanol, and ethanol was 202, 213, and 666 mPa·s, respectively, at 20 °C and 100 s−1, which is within the range of commercially available polyols. Successively, the JOLs were reacted with isophorone diisocyanate (IPDI) to produce polyurethane prepolymer by utilizing 2,2-dimethylol propionic acid (DMPA) as an emulsifier. The prepolymer was then dispersed in water to produce a waterborne polyurethane dispersion. Colloidal stability of the jatropha-based polyurethane dispersions (JPUDs) were investigated by particle size analysis. A JPUD with a small particle size in the range of 6.39 to 43.83 nm was obtained, and the trend was associated with the soft segment of the polyol in the formulation. The zeta potentials of the JPUs ranged from −47.01 to −88.9 mV, indicating that all synthesized JPUs had high dispersity and stability. The efficient synthesis procedure, low cost, and excellent properties of the resulting product are thought to offer an opportunity to use jatropha oil as a sustainable resource for polyester polyol preparation.

Environmentally-benign rigid polyurethane foam produced from a reactive and phosphorus-functionalized biopolyol: Assessment of physicomechanical and flame-retardant properties

In the present study, after the epoxidation reaction of sunflower oil (SF) was optimized using a response surface methodology (RSM) of central composite design (CCD), the oxirane ring-opening reaction of epoxidized SF was carried out with 1,4-butanediol, and consequently, the SF-based biopolyol (14BD-pol) was obtained. A novel and reactive phosphorylated biopolyol (DPP-14BD-pol) was synthesized using the Atherton-Todd reaction of diphenyl phosphite (DPP) with the 14BD-pol. The DPP-14BD-pol was characterized in detail and a series of environmentally-benign RPUFs were fabricated using one-shot and free-rising methods with the partial substitution of DPP-14BD-pol (10, 25, 50 php). The obtained bio-RPUFs were assessed through the effect of the increasing amount of DPP-14BD-pol on the morphology, physicomechanical, thermal, and flame retardant properties. With the increase in DPP-14BD-pol addition, the apparent density and compressive strength values of bio-based RPUFs increased from 43.1 to 46.7 kg/m3 and from 239 to 260 kPa, respectively. The thermal conductivity values of bio-based RPUFs varied between 27.49 and 28.14 mW/m.K. The cellular structures were in polyhedral form, and the cell size distributions were quite homogeneous. The LOI values slightly improved from 19.3% to 20.5% up to the amount of 50 php DPP-14BD-pol. These results show that DPP-14BD-pol can partly replace the petroleum-based polyol to synthesize water-blown bio-based RPUFs with the properties that meet the demands of the polyurethane industry.

Epoxidation of used cooking oils: Kinetic modeling and reaction optimization

This work developed a kinetic model for the epoxidation of used cooking oils (UCOs) via Prileschajew reaction with peracetic acid formed in situ. Such models, that have been not reported, are required for process design to assess feasibility of exploitation of UCOs as feedstock in the production of value-added oleochemical epoxides. The study evaluated the impact of reaction temperature and H2O2 loading on the oxirane yield, under constant loading of acetic acid (5% wt.), using H2SO4 as catalyst (2% wt.). Experiments were monitored by quantifying oxirane oxygen content along reaction, and the assessed conditions were defined based upon a factorial design. Considering a two-phase reactive media, two kinetic models were proposed and the corresponding kinetic parameters were adjusted by regression of the experimental data. It was found that the model that included two oxirane ring opening reactions pathways better described the experimental results, and that it can be further used for process design and scale up. Finally, the validated model was used to optimize a batch UCOs epoxidation by mean of a multi-objective optimization approach. Results indicate that conversions below 88% are required to avoid oxirane ring opening reaction, obtaining a product with an oxirane oxygen content of 4.4% wt.

Olefin-Metathesis-Derived Norbornene-Ethylene-Vinyl Acetate/Vinyl Alcohol Multiblock Copolymers: Impact of the Copolymer Structure on the Gas Permeation Properties.

Commercial metathesis polynorbornene is used for the fabrication of high-damping coatings and bulk materials that dissipate vibration and impact energies. Functionalization of this non-polar polymer can improve its adhesive, gas barrier, and other properties, thereby potentially expanding its application area. With this aim, the post-modification of polynorbornene was carried out by inserting ethylene–vinyl acetate–vinyl alcohol blocks into its backbone via the cross-metathesis of polynorbornene with poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers. For the first time, epoxy groups were introduced into the main chains of these copolymers, followed by the oxirane ring opening reaction. The influence of post-modification on the thermal, gas separation, and mechanical properties of the new copolymers was studied. It was shown that the gas permeability of the copolymer significantly depends on its composition, as well as on the amounts of hydroxyl and epoxy groups. The developed methods efficiently improve the barrier properties, reducing the oxygen permeability by 15–33 times in comparison with polynorbornene. The obtained results are promising for various applications and can be extended to a broader family of polydienes and other polymers containing backbone double bonds.

Nanoconfined anti-oxidizing RAFT nitroxide radical polymer for reduction of low-density lipoprotein oxidation and foam cell formation.

Atherosclerosis is a leading cause of death worldwide. Antioxidant therapy has been considered a promising treatment modality for atherosclerosis, since reactive oxygen species (ROS) play a major role in the pathogenesis of atherosclerosis. We developed ROS-scavenging antioxidant nanoparticles (NPs) that can serve as an effective therapy for atherosclerosis. The newly developed novel antioxidant ROS-eliminating NPs were synthesized via reversible addition–fragmentation chain-transfer (RAFT) polymerization and act as a superoxide dismutase (SOD) mimetic agent. SOD is an anti-ROS enzyme which is difficult to use for passive delivery due to its low half-life and stability. Copolymers were synthesized using different feed ratios of 2,2,6,6-tetramethyl-4-piperidyl methacrylate (PMA) and glycidyl methacrylate (GMA) monomers and an anti-ROS nitroxyl radical polymer was prepared via oxidation. The copolymer was further conjugated with a 6-aminofluorescein via a oxirane ring opening reaction for intracellular delivery in RAW 264.7 cells. The synthesized copolymers were blended to create NPs (∼150 nm size) in aqueous medium and highly stable up to three weeks. The NPs were shown to be taken up by macrophages and to be cytocompatible even at high dose levels (500 μg mL−1). Finally, the nitroxide NPs has been shown to inhibit foam cell formation in macrophages by decreasing internalization of oxidized low-density lipoproteins.

Impact of Different Epoxidation Approaches of Tall Oil Fatty Acids on Rigid Polyurethane Foam Thermal Insulation.

A second-generation bio-based feedstock—tall oil fatty acids—was epoxidised via two pathways. Oxirane rings were introduced into the fatty acid carbon backbone using a heterogeneous epoxidation catalyst-ion exchange resin Amberlite IR-120 H or enzyme catalyst Candida antarctica lipase B under the trade name Novozym® 435. High functionality bio-polyols were synthesised from the obtained epoxidated tall oil fatty acids by oxirane ring-opening and subsequent esterification reactions with different polyfunctional alcohols: trimethylolpropane and triethanolamine. The synthesised epoxidised tall oil fatty acids (ETOFA) were studied by proton nuclear magnetic resonance. The chemical structure of obtained polyols was studied by Fourier-transform infrared spectroscopy and size exclusion chromatography. Average molecular weight and polydispersity of polyols were determined from size exclusion chromatography data. The obtained polyols were used to develop rigid polyurethane (PU) foam thermal insulation material with an approximate density of 40 kg/m3. Thermal conductivity, apparent density and compression strength of the rigid PU foams were determined. The rigid PU foams obtained from polyols synthesised using Novozym® 435 catalyst had superior properties in comparison to rigid PU foams obtained from polyols synthesised using Amberlite IR-120 H. The developed rigid PU foams had an excellent thermal conductivity of 21.2–25.9 mW/(m·K).

Production of biolubricants from soybean oil: Studies for an integrated process with the current biodiesel industry

The competitiveness of the biodiesel industry may be improved by adding value through co-products and integration with the oleochemical industry, especially for novel products such as biolubricants, a product of increasing world demand. In this study the synthesis of biolubricants from soybean oil was evaluated using transesterification, epoxidation and oxirane ring opening reactions. Water, 2-ethylhexanol and their mixtures were used to obtain hydroxyl-rich and/or ether-type branched molecules. All chemical modifications were monitored by Nuclear Magnetic Resonance (1H NMR) and evaluated through the physicochemical properties of the products. Several potential biolubricant samples were synthesized with viscosities at 40 °C ranging from 26.6 to 99.6 cSt, viscosity index from 26 to 139, densities at 20 °C from 0.925 to 0.964 g/cm3, and pour points from −3 to −12 °C. From these results, a proposal of a feasible industrial process for the production of biolubricants from soybean oil is presented, consisting of 16 units, of which 15 may be integrated with an existing biodiesel plant.

Synthesis of a potential bendamustine deschloro dimer impurity

Bendamustine deschloro dimer was considered as a potential impurity in bendamustine hydrochloride resulting from the hydrolysis of bendamustine followed by intermolecular esterification. An efficient synthesis of bendamustine deschloro dimer was achieved from 4-(5-amino-1-methyl-1H-benzo[d]imidazol-2-yl)butanoate involving nine sequential steps including benzyl-protection/deprotection of the amine and carboxylic acid groups, saponification, ring-opening reaction of oxirane as well as Fischer/Steglish esterfication and so on. The target bendamustine deschloro dimer was obtained using a high-performance liquid chromatography in a purity of 95.63%.

Selenium-Epoxy ‘Click’ Reaction and Se-Alkylation—Efficient Access to Organo-Selenium and Selenonium Compounds

This work establishes the ‘click’ nature of the base-catalyzed oxirane ring opening reaction by the selenolate nucleophile. The ‘click’-generated ß-hydroxy selenide can be alkylated to afford cationic selenium species. Hemolytic studies suggest that selenonium cations do not lyse red blood cells even at high concentrations. Overall, these results indicate the future applicability of the developed organo-selenium chemistry in the preparation of a new class of cationic materials based on the seleno-ether motif.

Detailing the elementary stages in the oxirane ring opening reactions with carboxylic acids catalyzed by tertiary amines

AbstractThe study of the reaction systems “R3N – proton‐donor reagent (NuH) – epichlorohydrin” using a complex of various kinetic methods of investigation allowed the reaction pathway and the catalysis mechanism of the oxirane ring opening by proton‐donor reagents in the presence of R3N to be detailed. It was confirmed that the catalytic activity of R3N consists in their quaternization by oxirane under the obligatory condition of its electrophilic assistance with the NuH reagent. The quaternization process of tertiary amines was studied using 1H NMR and UV spectroscopy, quantum chemical modeling, and correlation analysis. It was shown that the transition states of the quaternization stage are dissociative, and their degree of looseness depends on the electrophilic activation of the oxirane ring.

Synthesis and Characterization of Potential Bio‐Based Lubricant Basestocks via Epoxidation Process

AbstractChemical modifications of vegetable oils may be applied for the purpose of improving their physicochemical properties in their usage for the bio‐based lubricants. The vegetable oils with a high percentage of oleic acid, such as soybeans and rapeseed oils, are important raw materials to obtain the biolubricants. In this particular study, the oleic acid was esterified with 1‐octanol, followed by epoxidation. The oxirane ring opening reaction was performed using different alcohol structures (linear, branched, and cyclic), in order to evaluate their influence on the final physicochemical properties with the synthesized samples. These aforesaid reaction steps were followed by 1H nuclear magnetic resonance and the main physicochemical properties in the intermediate and final samples were assessed. The highest oxidative stability was observed for the samples obtained, using a cyclic alcohol at the oxirane ring opening reaction (230 min), followed by the linear alcohols with the branched alcohol presenting the lowest oxidative stability (124 min). The pour point values for the samples synthesized with the branched alcohol were slightly better than those with the linear and cyclic alcohols. All the synthesized samples showed high viscosity indexes (>130) and kinematic viscosities at 40 °C, ranging from 30 to 33 cSt (application degree ISO VG‐32), which are adequate for their use in the formulation of bio‐based lubricants.

Bio-lubricants synthesis from the epoxidized oil promoted by clays: Kinetic modelling

Bio-based lubricants are an attractive class of products, gaining more attention in the recent years. The production of bio-based lubricants starting from vegetable oils derivates (e.g. epoxidized) and alcohols is gaining relevance among the various synthetic routes. Brøensted acids are normally used to promote the oxirane ring opening reaction, obtaining interesting products depending on the branching and chain length of the alcohol molecule. The use of homogeneous catalysts leads to evident drawbacks that could be overcome by replacing them with heterogeneous catalysts. Clays can be considered good candidates as they show reasonable acidity and are characterized by high availability and low price. In the present paper, the use of TONSIL EX 2166 was demonstrated to be a good candidate for the synthesis of bio-lubricant bases in the presence of 2-butanol. A kinetic model was proposed to describe the physical and chemical phenomena occurring in the reaction network.

A Computational Study of 2-(chloromethyl)oxirane Ring Opening by Bromide and Acetate Anions Considering Electrophilic Activation with Cations of Alkali Metals

Ring opening of 2-(chloromethyl)oxirane via the nucleophilic substitution with bromide and acetate anions was investigated using density functional theory (DFT) calculations. It was shown that the geometry of the transition states and the activation parameters of the reactions correspond to those of SN2-like mechanism. The nature of localized transition states was analyzed using More O’Ferrall – Jencks plots. The quantum chemical simulations of the potential energy surface for the ring-opening reaction of oxirane by nucleophiles confirmed the theoretical assumptions about the favored path of interactions, which is a backside α-attack of nucleophile. The effect of alkali metal cation (Li+, Na+, K+) on that path was estimated. It was found that the electrophilic activation with alkali metal cation is more pronounced in the reaction of 2-(chloromethyl)oxirane with dissociated ions, than with ionic pairs.

Behavior of epichlorohydrin catalytic acidolysis reaction with the variation of solvent polarity

The kinetics of the reaction of epichlorohydrin ((2-chloromethyl)oxirane) with acetic acid at 60 °C was studied in the presence of the catalyst—tetrabutylammonium iodide either in epichlorohydrin, or a binary solvent epichlorohydrin:tetrahydrofuran. The ratios of the binary solvent components were selected in order to preserve the excess of epichlorohydrin as the condition for pseudoorder with respect to the oxirane reactant. As the order of the reaction with respect to acid may differ depending on the reaction series, it was determined by kinetic and modelling methods. The correlation between solvent permittivity and observed and catalytic reaction rate constants was established. The equation for predicting tetrabutylammonium iodide catalytic reactivity in the binary solvent was obtained. The effect of solvent polarity on the rate and mechanism of oxirane ring opening reaction in the presence of a base catalyst was estimated via Laidler–Eyring equation. It was shown that the decrease of solvent polarity increases the reaction rate and its regioselectivity.

An easy one-step procedure for the synthesis of novel β-functionalised tellurides

Novel β-hydroxy-,β-amino- and β-mercapto- dialkyl- and phenyl-alkyl tellurides have been achieved through regioselective ring opening reactions of oxiranes, aziridines and thiiranes with different Te-nucleophiles, including tellurosilanes. Tellurium-125 NMR chemical shifts of selected compounds have been measured.