Synthesis and characterization of polyurethanes from epoxidized methyl oleate based polyether polyols as renewable resources

Methyl oleate for plant protection products formulations: Enzymatic synthesis, reaction kinetics and application testing

This study presents a solvent-free enzymatic approach for the synthesis of fatty acid methyl esters (FAMEs), such as methyl oleate, for their application as adjuvant in plant protection products (PPP) formulations. The direct esterification between free fatty acid and methanol was optimized to achieve 98% acid conversion. The kinetics of this conversion was accurately described by a simple second order mechanism and non-linear regression was applied to calculate the rate constants of the forward and backward reactions based on full progress curves data. The rate constant of the forward reaction (synthesis) was one order of magnitude higher than the backward reaction (hydrolysis) and favored formation of the target methyl ester product, rendering the removal of water unnecessary. Enzymatically synthesized methyl oleate was benchmarked against the chemically synthesized compound, showing matching results in terms of stability, spreadability and emulsifying capacity in plant care formulations. The enzymatic synthesis of FAMEs under solvent free conditions allows to achieve a safer and more sustainable character for carrier solvents in PPP formulations.

Individual and Joint Effect of Alpha-Tocopherol and Hydroxytyrosol Acetate on the Oxidation of Sunflower Oil Submitted to Oxidative Conditions: A Study by Proton Nuclear Magnetic Resonance

This study tackles the individual and joint effect of alpha-tocopherol and hydroxytyrosol acetate on the oxidation of sunflower oil submitted to accelerated storage conditions at intermediate temperature, in order to deepen the understanding of antioxidant–prooxidant behaviour. This was accomplished by ¹H Nuclear Magnetic Resonance. For this purpose, the evolution of the degradation of both the main components of the oil and the aforementioned added compounds was monitored by this technique throughout the storage time. Furthermore, the formation of a very large number of oxylipins and the evolution of their concentration up to a very advanced stage of oil oxidation, as well as the occurrence of lipolysis, were also simultaneously studied. The results obtained show very clearly and thoroughly that in the oxidation process of the oil enriched in binary mixtures, interactions occur between alpha-tocopherol and hydroxytyrosol acetate that notably reduce the antioxidant effect of the latter compound with the corresponding negative consequences that this entails. The methodology used here has proved to be very efficient to evaluate the antioxidant power of mixtures of compounds.

Influence of Hydroxytyrosol Acetate Enrichment of an Oil Rich in Omega-6 Groups on the Evolution of Its Oxidation and Oxylipin Formation When Subjected to Accelerated Storage. A Global Study by Proton Nuclear Magnetic Resonance

Sunflower oil samples, both unenriched and enriched with four different concentrations of hydroxytyrosol acetate, were subjected to accelerated storage at 70 °C until a very advanced oxidation stage and the process was monitored by ¹H NMR spectroscopy. The aim of the study is to know the effect that the presence of this antioxidant has on the oxidation process of sunflower oil under the aforementioned conditions, as well as on the formation and evolution of the concentration of a significant number of oxylipins. The oxidation process was studied globally by monitoring, during storage time, the degradation of both the linoleic acyl group of sunflower oil, which is the main component of sunflower oil, and the added hydroxytyrosol acetate. Simultaneously, the identification of up to twenty-six different types of oxylipins formed in the oxidation process and the monitoring of the evolution of their concentration over the storage time were carried out. In this way, essential information about the effect that hydroxytyrosol acetate provokes on the oxidation of this oil rich in omega-6 polyunsaturated acyl groups, has been obtained. It has also been shown that the enrichment of sunflower oil with this antioxidant under the conditions tested does not prevent the oxidation process but slows it down, affecting the entire oxidation process.

Alpha-Tocopherol, a Powerful Molecule, Leads to the Formation of Oxylipins in Polyunsaturated Oils Differently to the Temperature Increase: A Detailed Study by Proton Nuclear Magnetic Resonance of Walnut Oil Oxidation

Lipid oxidation causes food degradation and the formation of toxic compounds. Therefore, the addition to foods of compounds able to avoid, delay or minimize this degradative process is a commonly used strategy. Nevertheless, neither the identity of most of the formed compounds in this complex process nor the way in which their formation is affected by the strategy used are well known. In this context, the effect the temperature increase and the enrichment level in alpha-tocopherol on the evolution of the walnut oil oxidation, as a model of an oil rich in polyunsaturated omega-6 acyl groups, submitted to storage conditions, are tackled by ¹H NMR. The study has allowed knowing the degradation kinetic of both the oil acyl groups and alpha-tocopherol, the identification of a very high number of oxylipins and the kinetic of their formation. The temperature increase accelerates the formation of all oxylipins, favouring the formation of hydroperoxy conjugated E,E-dienes and related derivatives versus that of the Z,E-isomers. The enrichment in alpha-tocopherol accelerates the formation of hydroperoxy conjugated Z,E-dienes and related derivatives, and delays in relation to the formation of the former that of the E,E-isomers and related derivatives, hindering, to a certain extent, the formation of the latter in line with the enrichment level.

A 5-(2-Pyridyl)tetrazolate Complex of Molybdenum(VI), Its Structure, and Transformation to a Molybdenum Oxide-Based Hybrid Heterogeneous Catalyst for the Epoxidation of Olefins

There is a considerable practical interest in discovering new ways to obtain organomolybdenum heterogeneous catalysts for olefin epoxidation that are easier to recover and reuse and display enhanced productivity. In this study, the complex salt (H2pytz)[MoO2Cl2(pytz)] (1) (Hpytz = 5-(2-pyridyl)tetrazole) has been prepared, structurally characterized, and employed as a precursor for the hydrolysis-based synthesis of a microcrystalline molybdenum oxide/organic hybrid material formulated as [MoO3(Hpytz)] (2). In addition to single-crystal X-ray diffraction (for 1), compounds 1 and 2 were characterized by FT-IR and Raman spectroscopies, solid-state 13C{1H} cross-polarization (CP) magic-angle spinning (MAS) NMR, and scanning electron microscopy (SEM). Compounds 1 and 2 were evaluated as olefin epoxidation catalysts using the model reaction of cis-cyclooctene (Cy8) with tert-butyl hydroperoxide (TBHP), at 70 °C, which gave 100% epoxide selectivity up to 100% conversion. While 1 behaved as a homogeneous catalyst, hybrid 2 behaved as a heterogeneous catalyst and could be recovered for recycling without showing structural degradation or loss of catalytic performance over consecutive reaction cycles. The substrate scope was broadened to monoterpene DL-limonene (Lim) and biobased unsaturated fatty acid methyl esters, methyl oleate (MeOle), and methyl linoleate (MeLin), which gave predominantly epoxide products.

Slug flow as tool for selectivity control in the homogeneously catalysed solvent-free epoxidation of methyl oleate

Catalytic oxidation of sustainable raw materials like unsaturated fats and oils, or fatty acids and their esters, lead to biobased, high-value products. Starting from technical grade methyl oleate, hydrogen peroxide as a green oxidant produces only water as by-product. A commercially available, cheap water-soluble tungsten catalyst is combined with Aliquat® 336 as a phase-transfer agent in solvent-free reaction conditions. In this study, we first report the transfer of this well-known batch system into continuous mode. The space–time yield is improved from 0.08 kg/L.h in batch to 1.29 kg/L.h in flow mode. The improved mass transfer and reduced back mixing of the biphasic liquid–liquid slug flow allows for selectivity control depending on physical parameters of slug flow namely volumetric phase ratio, volumetric flow rate, and slug length. Even though the product, methyl 9,10-epoxystearate is obtained at a maximum selectivity of only 58% in flow mode, higher space time yield combined with possible reactant recycling in flow mode offers a promising avenue of research. This work analyses the use of slug flow parameters as tools for controlling selectivity towards oxidation products of methyl oleate.

An efficient and environment friendly bio-based polyols through liquefaction: Liquefaction temperature and catalyst concentration optimization and utilized for rigid polyurethane foams

Aiming towards the liquefaction of paddy straw was accumulation as well as providing a technically viable route leading to preservation of the natural resources and environment, the paddy straw was chemically liquefied. Paddy straw were liquefied into bio-based polyol in the presence of castor oil and blend of castor and karanja oil as depolymerizing agent and P-Toluene sulfonic acid as catalyst. Liquefied product was characterized by chemical as well as analytical techniques. The agricultural waste base paddy straw was eventually converted into polymeric precursor (polyol) monomer with nearly 80 to 95% yield by employing 2% catalyst concentration and at optimized temperature of 180°C. Synthesized polyol can be utilized further in formulating high quality rigid polyurethane foams. The foams were characterized in terms of their physical, mechanical, thermal and morphological properties. All foams exhibit good compressive strengths and thermal stability. Thermal conductivity of foams varied between 0.012 and 0.023 Kcal/mh°C, with the lowest being of foam from liquefied (LP), making it suitable for utilization as an insulation material.

Plant oil-based polymers

Polymer materials derived from natural resources have gained increasing attention in recent years because of the uncertainties concerning petroleum supply and prices in the future as well as their environmental pollution problems. As one of the most abundant renewable resources, plant oils are suitable starting materials for polymers because of their low cost, the rich chemistry that their triglyceride structure provides, and their potential biodegradability. This chapter covers the structure, modification of triglycerides and their derivatives as well as synthesis of polymers therefrom. The remarkable advances during the last two decades in organic synthesis using plant oils and the basic oleochemicals derived from them are selectively reported and updated. Various methods, such as condensation, radical/cationic polymerization, metathesis procedure, and living polymerization, have also been applied in constructing oil-based polymers. Based on the advance of these changes, traditional polymers such as polyamides, polyesters, and epoxy resins have been renewed. Partial oil-based polymers have already been applied in some industrial areas and recent developments in this field offer promising new opportunities.

Oxylipins Associated to Current Diseases Detected for the First Time in the Oxidation of Corn Oil as a Model System of Oils Rich in Omega-6 Polyunsaturated Groups. A Global, Broad and in-Depth Study by 1H NMR Spectroscopy

For the first time, an important number of oxylipins have been identified and quantified in corn oil submitted to mild oxidative conditions at each time of their oxidation process. This oil can be considered as a model system of edible oils rich in polyunsaturated omega-6 groups. The study was carried out using 1H nuclear magnetic resonance spectroscopy (1H NMR), which does not require chemical modification of the sample. These newly detected oxylipins include dihydroperoxy-non-conjugated-dienes, hydroperoxy-epoxy-, hydroxy-epoxy- and keto-epoxy-monoenes as well as E-epoxy-monoenes, some of which have been associated with several diseases. Furthermore, the formation of other functional groups such as poly-formates, poly-hydroxy and poly-ether groups has also been proven. These are responsible for the polymerization and increased viscosity of the oil. Simultaneously, monitoring of the formation of well-known oxylipins, such as hydroperoxy-, hydroxy-, and keto-dienes, and of different kinds of oxygenated-alpha,beta-unsaturated aldehydes such as 4-hydroperoxy-, 4-hydroxy-, 4-oxo-2E-nonenal and 4,5-epoxy-2E-decenal, which are also related to different degenerative diseases, has been carried out. The provided data regarding the compounds identification and their sequence and kinetics of formation constitute valuable information for future studies in which lipid oxidation is involved, both in food and in other scientific fields.

Renewable Responsive Systems Based on Original Click and Polyurethane Cross-Linked Architectures with Advanced Properties

A new chemical architecture from oleic acid, consisting of a diol structure containing pendant furan rings, denoted the furan oligomer (FO) was synthesized and fully characterized. The FO was integrated into a linear rapeseed-based polyurethane (PU) backbone and cross-linked through a Diels-Alder (DA) reaction by using pendant furan rings and a short polypropylene oxide-based bismaleimide. This is the first time that a thermoreversible PU network based on vegetable oil has been reported. The effects of varying proportions of FO in linear and cross-linked systems, by DA, were studied. These materials were analyzed by classic characterization techniques. The stability and recyclability of the cross-linked materials were shown by successive reprocessing cycles and reanalyzing the mechanical properties. Self-healing properties were macroscopically exhibited and investigated by tensile tests on healed materials. The resulting cross-linked materials present a large range of properties, such as tunable mechanical and thermoresponsive behavior, good thermal recyclability, and self-healing abilities.

Epoxidación enzimática de metil ésteres de ácidos grasos de origen vegetal y sus aplicaciones como alternativa para sustituir a los derivados del petróleo

Recientemente, la modificación de aceites vegetales para obtener ésteres metílicos de ácidos grasos (FAMEs) o biodiesel ha emergido como una alternativa para la sustitución de los derivados del petróleo, esto debido a los problemas ambientales y de salud que genera su uso. Debido a su estructura química es posible epoxidar estas moléculas y usarlas directamente para producir plastificantes o lubricantes. Sin embargo, éstas también pueden ser sujetas a modificaciones para mejorar sus propiedades y el de servir como intermediarias para la síntesis de poliuretanos. Puesto que los métodos convencionales para la producción de epóxidos también son una fuente potencial de contaminación, se ha sugerido el uso de catalizadores enzimáticos como una alternativa sostenible o “Verde” para su preparación, ya que permiten obtener productos con alta pureza y mejores rendimientos. Este artículo presenta una revisión de la literatura disponible centrándose en la epoxidación enzimática de los FAMEs, así como sus principales aplicaciones.

Jatropha seed oil derived poly(esteramide-urethane)/ fumed silica nanocomposite coatings for corrosion protection

Jatropha oil [JO] based poly (esteramide-urethane) coatings embedded with fumed silica nanoparticles were prepared. JO was converted to N,N-bis(2-hydroxy ethyl) JO fatty amide (HEJA) and was further modified by a tetrafunctional carboxylic acid(trans 1,2 diaminocyclo-hexane-N,N,N’,N’,-tetraacetic acid) to form poly (diamino cyclohexane esteramide) (PDCEA). PDCEA was then treated with toluene 2,4-diisocynate and fumed silica to prepare poly(diamino cyclohexane urethane esteramide) (PUDCEA) nanocomposite. The formation of PDCEA and PUDCEA nanocomposites was confirmed by FTIR, 1H &13C NMR spectroscopic techniques. The thermal behavior and morphology of PUDCEA nanocomposite coatings were investigated by TGA/DTG, DSC, SEM, EDX spectroscopy. PUDCEA nanocomposites were applied on carbon steel and their coatings were produced at room temperature. The properties of these nanocomposite coatings were investigated by standard analytical methods. The PUDCEA-3 nanocomposite showed good anticorrosion and physico-mechanical performance. These naocomposite coatings can be employed safely upto 200oC.

Tailoring Acrylated Soybean Oil-Containing Terpolymers through Emulsion Polymerization

This work focuses on the synthesis of terpolymers using methyl methacrylate (MMA) and vinyl pivalate (VPi), along with the incorporation of methacrylate acid (MA) and acrylated fatty acids (AFA) derived from commercial soybean oil. Emulsion polymerizations were carried out using different monomeric species, along with different initiator concentrations ranging from 0.5 g∙L−1 to 2.2 g∙L−1. The thermal properties of the terpolymers were improved when acrylated fatty acid was incorporated into the polymer chains, expressing glass transition temperatures (Tg) ranging from 70 °C to 90 °C and degradation temperatures in the interval between 350 °C and 450 °C for acrylated fatty acid concentrations ranging from 5 wt% to 10 wt%. Furthermore, a change was noted in the molar mass distributions as a result of acrylated fatty oil present in the polymers. The materials with 5 and 10 wt% of acrylated fatty oil presented mass-average molar masses of 225 kg∙mol−1 and 181 kg∙mol−1, respectively. As the results in this work suggest, the molar masses of the formed polymers are significantly altered by the presence of modified fatty acids.

Microwave-Assisted Catalytic Synthesis of Bio-Based Copolymers from Waste Cooking Oil

Solvent-free copolymerization of epoxides derived from fatty esters of waste cooking oil with phthalic anhydride using (salen)Cr^IIICl as catalyst and n-Bu₄NCl/DMAP (tetrabutylammonium chloride/4-(dimethylamino)pyridine) as co-catalysts was carried out for the first time under microwave irradiation, where reaction time was reduced from a number of hours to minutes. The polyesters were obtained with molecular weight (Mw = 3100–6750 g/mol) and dispersity values (D = 1.18–1.92) when (salen)Cr^IIICl/n-Bu₄NCl was used as catalysts. Moreover, in the case of DMAP as a co-catalyst, polyesters with improved molecular weight (Mw = 5500–6950 g/mol) and narrow dispersity values (D = 1.07–1.28) were obtained even at reduced concentrations of (salen)Cr^IIICl and DMAP. The obtained products were characterized and evaluated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), proton nuclear magnetic resonance (¹H-NMR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) Techniques.

Industrial resin “INDION 130” modified with vanadyl cations as highly efficient heterogeneous catalyst for epoxidation of fatty compounds with TBHP as oxidant

Cation exchanger INDION 130 modified with vanadyl cations was found to be readily prepared and reusable and exhibited higher catalytic activity than the homogeneous oxo-vanadium catalyst for epoxidation of fatty compounds.

Ring-opening polymerization of ω-6-hexadecenlactone by a salicylaldiminato aluminum complex: a route to semicrystalline and functional poly(ester)s

The homo and co-polymerization of a large ring size lactone afforded unsaturated poly(esters), further modified to functional thermoplastic materials.

Synthesis and characterization of polyurethanes made from copolymers of epoxidized natural oil and tetrahydrofuran

Polyols were synthesized from epoxidized natural oils and tetrahydrofuran through ring opening copolymerization catalyzed by Lewis acid. The properties of these polyols depend on the type of natural oils as well as the reaction conditions (monomer concentration, catalyst amount, reaction temperature and reaction time). These polyols were evaluated as a raw material for making polyurethane (PU) in order to understand the structure-property relationship between a natural oil and PU made from it. The tensile test analysis shows that the incorporation of natural oil moiety into the PU polymer network improves the elasticity of these PU samples when compared to a benchmark PU sample. In addition, the PU samples made from palm oil and soybean oil based polyols exhibit better tensile strength than benchmark PU. These polyols samples are suitable for making elastomeric PU, where high flexibility (high elongation at break) of PU is a common requirement.

Vegetable-oil-based polymers as future polymeric biomaterials

Vegetable oils are one of the most important classes of bio-resources for producing polymeric materials. The main components of vegetable oils are triglycerides - esters of glycerol with three fatty acids. Several highly reactive sites including double bonds, allylic positions and the ester groups are present in triglycerides from which a great variety of polymers with different structures and functionalities can be prepared. Vegetable-oil-based polyurethane, polyester, polyether and polyolefin are the four most important classes of polymers, many of which have excellent biocompatibilities and unique properties including shape memory. In view of these characteristics, vegetable-oil-based polymers play an important role in biomaterials and have attracted increasing attention from the polymer community. Here we comprehensively review recent developments in the preparation of vegetable-oil-based polyurethane, polyester, polyether and polyolefin, all of which have potential applications as biomaterials.