Unsaturated Diacids Research Articles

Fully bio-based and intrinsically flame retardant unsaturated polyester cross-linked with isosorbide-based diluents

Unsaturated polyester resins (UPR) are composed of prepolymers and styrene diluents, while the former are produced by co-polycondensation between diol, unsaturated diacid and saturated diacid. In this work, bio-based UPR prepolymers were synthesized from bio-based oxalic acid, itaconic acid, and ethylene glycol, which were then diluted with bio-based isosorbide methacrylate (MI). Meanwhile, the phenylphosphonate were introduced into the molecular chains of prepolymers to achieve intrinsic flame retardancy of bio-based UPR. The potential of the reactive MI diluents as substitutes of volatile styrene, was also assessed through the volatility test, curing kinetics and gel contents analysis. For UPR materials with styrene diluents, the UPR materials can achieve UL-94 V0 level and the 28% of limiting oxygen index (LOI) with 2.63 wt% of phosphorus contents. By contrast, the UPR materials with MI diluents can reach UL-94 V0 level with only 2.14 wt% of phosphorus contents. As the phosphorus contents were further increased to 2.63 wt%, UPR materials can achieve highest 29%, while the peak of heat release rate (PHRR) and total heat release (THR) were decreased by 68.01% and 48.62%, respectively. The Flame Retardancy Index (FRI) was also used to comprehensively evaluate the flame retardant performance of UPR composites. Compared with neat UPR, the composites with MI diluents and phosphorus containing structures increased from 1.00 to 6.46. The mechanism for improved flame retardancy was analyzed from gaseous and condensed phase. Additionally, the tensile strengths of bio-based UPR materials with styrene and MI diluents were studied. This work provides an effective method to prepared high-performance and fully bio-based UPR materials with improved flame retardant properties and safety application of reactive diluents.

The conversion of woody oils into E-octadec-9-enedioic acid and multiple-shape memory polyamides

Although tremendous efforts have been made to convert woody oils into valuable chemicals, most of the known protocols still require multi-step procedures and rigorous conditions. Herein, a highly efficient method for converting woody oils into long-chain unsaturated dicarboxylic acid was reported. Such a strategy holds promises for opening new routes for utilizing woody oils. Firstly, self-metathesis of fatty acids from Rubber seed oil (RSO), Sapium sebiferum oil (SSO) and High oleic Canola oil (HOCO) were optimized. Pure E -octadec-9-enedioic acid monomer (C18) was obtained, and confirmed by 1 H NMR and FTIR spectra. The prepared dicarboxylic acid was then experienced condensation polymerization with 1,6-hexamethylenediamine. The chemical structures of the obtained polyamides were investigated by FTIR and 13 C NMR spectra. DSC, TGA, DMA, and tensile testing was used to explored their thermal and mechanical properties. Interestingly, due to the existence of broad melting and glass transition, the prepared polyamides possess multiple-shape memory properties. • Woody oils were successfully converted into long-chain unsaturated diacid via self-metathesis. • Although woody oils contain high content of polyunsaturated fatty acids, only C18 were obtained via self-metathesis. • Mechanical strong polyamides with multiple shape-memory property were obtained via polycondensation.

Alpine snowpit profiles of polar organic compounds from Mt. Tateyama central Japan: Atmospheric transport of organic pollutants with Asian dust

Snowpit samples (n = 10) were collected (19 April 2008) from the snowpit sequences (depth 6.60 m) at the Murodo-Daira site (36.58°N, 137.60°E, elevation of 2450 m a.s.l.) of Mt. Tateyama (3015 m a.s.l.), central Japan. The first time, low molecular weight diacids, ω-oxoacids, pyruvic acid, and α-dicarbonyls were measured for this snowpit sequence. Higher concentrations of short-chain diacids (C2–C5) are observed in dusty snow than non-dusty snow samples. Longer chain diacids (C7–C12) are significant in granular and dusty snow samples. Aromatic and aliphatic unsaturated diacids showed higher concentrations in the slightly dusty layer deposited in winter. Except for a clean layer, molecular distributions of diacids are characterized by the predominance of oxalic acid (C2, ave, 20 ± 22 ng/g-snow) followed by succinic (C4, 7.2 ± 5.9 ng/g -snow), and malonic acids (C3, 3.3 ± 2.9 ng/g -snow) for all the snow layers. Lower C3/C4 ratios (0.46) suggest that organic aerosols are rather fresh without serious photochemical aging during the long-range transport over central Japan. The higher concentrations of the secondary species in dusty snow than non-dusty samples were mainly attributed to the heterogeneous reaction. The strong correlations of incloud oxidation products of isoprene, aromatic acids, and fatty acids suggest that condensation, oxidation, and photolysis are important reaction mechanisms for the formation of diacids. Chinese Loess (Kosa particles) and Mongolian Gobi desert's dust provided the surface area for polar organic compounds, traveled to several thousand kilometers in the lower troposphere, and snow metamorphism altered the chemical composition of diacids and related compounds.

Deciphering the structure of itaconate‐based unsaturated polyester resins by high resolution mass spectrometry

AbstractUnsaturated polyester (UP) resins are widely used to manufacture composite materials and fulfil a wide panel of specification for industrial or domestic applications at low cost. These resins consist of a highly viscous polyester oligomer and a reactive diluent, which allow their processability and crosslinking. The oligomers are synthesized from diols and saturated or unsaturated diacids. Maleic anhydride is classically used as an unsaturated acid because of its reactivity for esterification and its competitive cost. However, maleic anhydride is petroleum based and classified as skin and respiratory sensitizing by the European Chemicals Agency. Itaconic acid which is recognized as one of the top 12 biobased molecules by the US Department of Energy is a biobased alternative with a reactive unsaturation. In this work, a UP based on propylene glycol, itaconic acid and dimethyl terephthalate was synthesized by polycondensation and characterized by high resolution mass spectroscopy, 1H, 13C 1D and 2D NMR as well as ion mobility spectrometry mass spectrometry. The main structures were linear but cyclic species and a few branched chains due to the intermolecular Ordelt reaction were also detected by NMR and high resolution mass spectroscopy. Molecular modelling has indeed demonstrated that itaconate‐based UPs are more prone to cyclization than fumarate‐based UPs. Moreover, NMR analysis showed a significant consumption of itaconate unsaturation by the Ordelt reaction. Ion mobility spectrometry mass spectrometry allowed an additional structure to be distinguished for the same m/z peaks first attributed to a linear structure only. These results suggest the existence of cyclic species based on an intramolecular Ordelt reaction. © 2020 Society of Chemical Industry

Characterization of polypropylene itaconate in divinyl benzene and methylene bisacrylamide

The radical reaction of the unsaturated polyester from polycondensation of 1,3-Propanediol (PDO) and itaconic acid (IA) has been successfully performed to create a three-dimensional networking polyester with good thermal stability. Two different crosslinkers of divinyl benzene (DVB) and methylene bisacrylamide (MBA) have been radically reacted on the chain group of polypropylene itaconate (PPIA). The radical reaction of PPIA with DVB and MBA was achieved up to the addition of 30 and 15% (w/w) crosslinkers, respectively. PPIA reacted with aromatic-content of DVB showed higher thermal stability compared to acrylic derivate crosslinker of MBA. The increase in the crosslinking density on the propylene itaconate (PIA) slightly enhanced the thermal stability of the polyester. This study concludes that the limitation of the use of PDO as a raw material as a source for polyester could be avoided by a strategy of condensation with unsaturated diacids (as IAs) and radical reaction with crosslinking agents.

Electrochemical Conversion of Biologically Produced Muconic Acid: Key Considerations for Scale-Up and Corresponding Technoeconomic Analysis

Muconic acid, an unsaturated diacid that can be produced from cellulosic sugars and lignin monomers by fermentation, emerges as a promising intermediate for the sustainable manufacture of commodity polyamides and polyesters including Nylon-6,6 and polyethylene terephthalate (PET). Current conversion schemes consist in the biological production of cis,cis-muconic acid using metabolically engineered yeasts and bacteria, and the subsequent diversification to adipic acid, terephthalic acid, and their derivatives using chemical catalysts. In some instances, conventional precious metal catalysts can be advantageously replaced by base metal electrocatalysts. Here, we show the economic relevance of utilizing a hybrid biological–electrochemical conversion scheme to convert glucose to trans-3-hexenedioic acid (t3HDA), a monomer used for the synthesis of bioadvantaged Nylon-6,6. Potential roadblocks to biological and electrochemical integration in a single reactor, including electrocatalyst deactivation due to bioge...

A sub-decadal trend in diacids in atmospheric aerosols in eastern Asia

Abstract. Change in secondary organic aerosols (SOAs) has been predicted to be highly uncertain in the future atmosphere in Asia. To better quantify the SOA change, we examine the sub-decadal (2001–2008) trend in major surrogate compounds (C2–C10 diacids) of SOA in atmospheric aerosols from Gosan site on Cheju Island, South Korea. The Gosan site is influenced by pollution outflows from eastern Asia. The molecular distributions of diacids were characterized by the predominance of oxalic (C2) acid followed by malonic (C3) and succinic (C4) acids in each year. The seasonal variations in diacids in each year were characterized by the highest concentrations of saturated diacids in spring and unsaturated diacids in winter. The consistent molecular distributions and seasonal variations along with significantly similar air mass transport patterns are indicative of similar pollution sources for diacids in eastern Asia on a sub-decadal scale. However, the intensity of the pollution sources has increased as evidenced by the increases in major diacids at the rate of 3.9–47.4 % per year, particularly in April. The temporal variations in atmospheric tracer compounds (carbon monoxide, levoglucosan, 2-methyltetrols, pinic acid, glyoxylic acid, glyoxal and methylglyoxal) suggest that the increases in diacids are due to enhanced precursor emissions associated with more anthropogenic than biogenic activities followed by the compounds' chemical processing in the atmosphere. The trends in diacids contrast with the reported decreases in sulfate, nitrate and ammonium in recent years in eastern Asia. This study demonstrates that recent pollution control strategies in eastern Asia were not able to decrease organic acidic species in the atmosphere. The increases in water-soluble organic acid fraction could modify the aerosol organic composition and its sensitivity to climate relevant physical properties.

Separation of Itaconic Acid from Aqueous Solution onto Ion-Exchange Resins

Itaconic acid (IA) is an unsaturated diacid, a promising compound that might replace part of the petrochemical-based monomers, such as acrylic acid, as a building block for polymers. Recent developments in biotechnology allow the efficient production of IA through fermentation processes. However, further enhancements are necessary in the downstream (recovery) of the product. This investigation examined the separation of IA by adsorption from aqueous solutions, using two types of commercial, strongly basic ion-exchange resins: Purolite A-500P and PFA-300. To evaluate the separation process, the following parameters were tested: pH (from 3.03 to 6.33), temperature (from 10 to 50 °C), and IA concentration (from 0.41 to 6.50 g·L–1). The Freundlich and Langmuir isotherms were shown to be good fits to the experimental data, and the adsorption kinetics for IA was found to follow a pseudo-second-order (PSO) model. After batch tests, continuous adsorption experiments were carried out using a fixed bed column, and ...

Synthesis of unsaturated polyesters based on renewable monomers: Structure/properties relationship and crosslinking with 2-hydroxyethyl methacrylate

This work presents the preparation of unsaturated polyesters (UPs) with ‘high green content’ and their crosslinking reaction with 2-hydroxyethyl methacrylate (HEMA), to yield the unsaturated polyester resins (UPRs). The chemical structure analysis revealed the presence of mesaconate moieties in the UPs prepared with itaconic acid (IA) as the unsaturated diacid. These UPs were also characterized by high values of polydispersity (PDI), which is indicative of the presence of branched structures. The UPs have shown good thermal stability. The UPRs presented high gel content, which has shown to be dependent on the amount of HEMA in the formulation. The dynamic mechanical thermal analysis (DMTA) revealed the existence of two transitions, corresponding to the motion of different domains in the UPRs. The swelling tests revealed that the UPRs have a highly hydrophobic nature. The in vitro hydrolytic degradation tests showed that the UPRs are hardly degraded in a phosphate buffered saline solution (PBS), at pH=7.4 and 37°C.

Synthesis of Unsaturated Polyester Resins from Various Bio-Derived Platform Molecules.

Utilisation of bio-derived platform molecules in polymer synthesis has advantages which are, broadly, twofold; to digress from crude oil dependence of the polymer industry and secondly to reduce the environmental impact of the polymer synthesis through the inherent functionality of the bio-derived platform molecules. Bulk polymerisation of bio-derived unsaturated di-acids has been employed to produce unsaturated polyester (UPEs) which have been analysed by GPC, TGA, DSC and NMR spectroscopy, advancing on the analysis previously reported. UPEs from the diesters of itaconic, succinic, and fumaric acids were successfully synthesised with various diols and polyols to afford resins of MN 480–477,000 and Tg of −30.1 to −16.6 °C with solubilities differing based on starting monomers. This range of properties allows for many applications and importantly due to the surviving Michael acceptor moieties, solubility and cross-linking can be specifically tailored, post polymerisation, to the desired function. An improved synthesis of itaconate and succinate co-polymers, via the initial formation of an itaconate bis-diol, is also demonstrated for the first time, resulting in significantly improved itaconate incorporation.

Understanding Potentials and Restrictions of Solvent‐Free Enzymatic Polycondensation of Itaconic Acid: An Experimental and Computational Analysis

AbstractItaconic acid is a chemically versatile unsaturated diacid that can be produced by fermentation and potentially it can replace petrol‐based monomers such as maleic and fumaric acids in the production of curable polyesters or new biocompatible functionalized materials. Unfortunately, due to the presence of the unsaturated CC bond, polycondensation of itaconic acid is hampered by cross reactivity and isomerization. Therefore, enzymatic polycondensations would respond to the need of mild and selective synthetic routes for the production of novel bio‐based polymers. The present work analyses the feasibility of enzymatic polycondensation of diethyl itaconate and, for the first time, provides comprehensive solutions embracing both the formulation of the biocatalyst, the reaction conditions and the choice of the co‐monomers. Computational docking was used to disclose the structural factors responsible for the low reactivity of dimethyl itaconate and to identify possible solutions. Surprisingly, experimental and computational analyses revealed that 1,4‐butanediol is an unsuitable co‐monomer for the polycondensation of dimethyl itaconate whereas the cyclic and rigid 1,4‐cyclohexanedimethanol promotes the elongation of the oligomers.magnified image

Low molecular weight PEI-appended polyesters as non-viral gene delivery vectors

Routine clinical implementation of human gene therapy requires safe and efficient gene delivery methods. Linear biodegradable polyesters with carbon–carbon double bonds are prepared from unsaturated diacids and diols. Subsequent appending of low molecular weight PEI by Michael addition gives target cationic polymers efficiently. Agarose gel retardation and fluorescence quenching assays show that these materials have good DNA binding ability and can completely retard plasmid DNA at weight ratio of 0.8. The formed polyplexes have appropriate sizes around 275 nm and zeta-potential values about +20–35 mV. The cytotoxicities of these polymers assayed by MTT are much lower than that of 25 kDa PEI. In vitro transfection toward 7402, HEK293 and U-2OS cells show that polymer P1 may give dramatically higher transfection efficiency (TE) than 25 kDa PEI, especially in U-2OS cells, suggesting that such polymer might be promising non-viral gene vectors.

Study on Synthesis and Characterization of Unsaturated Polyester by Enzyme-Catalyzed

Unsaturated polyester was prepared with adipic acid (AA), fumaric acid (FA), itaconic acid (IA) and 1, 6-hexanediol (HD) by enzyme-catalyzed polmerization. The insoluble gel fraction (Qs), as the cross-linking degree of cured unsaturated polyesters which could be self-cross-linked at high temperature through C=C in it, was got by Soxhlet Extraction. The properties were investigated by FT-IR, 1H NMR, DSC, XRD and so on. The results indicated that the C=C in unsaturated diacids reduced the acitvity of N435, which affected the polmerization. With the introduction of C=C of IA or FA, the Mn of polyester reduced. The C=C could self-cross-link under high temperature for lengthy time. The higher the temperature and the longer the time, the Qs increased. As the C=C of IA was in the side chain, it could move easily. Then Qs of poly (AA-co-IA-co-HD) was higher than ploy (AA-co-FA-co-HD). With the increased content of unsaturated diacid, Qs increased. And the biodegradation of cross-linked polyesters became worse.

Gas/particle partitioning of low-molecular-weight dicarboxylic acids at a suburban site in Saitama, Japan

Abstract Low-molecular-weight dicarboxylic acids (diacids) exhibit semivolatile behavior in the atmosphere, but their partitioning between the gaseous and particulate phases is still unclear. An annular denuder–filter pack system with a cyclone PM2.5 was employed to investigate the gaseous and particulate phase concentrations of diacids, with high collection efficiency of most target compounds. Saturated diacids, unsaturated diacids, ketocarboxylic acids, and dicarbonyls were determined in gaseous and particulate samples collected from a suburban site in Japan, during 2007 summer, 2008 late-winter and early-winter. The concentrations of gaseous and particulate diacids in early-winter were lower than those in summer, but higher than those in late-winter. Individual diacid in gaseous phase showed a relatively good correlation with ambient oxidants, but a low correlation with NO gas (a primary pollutant). Particulate fraction to the total amount (FP) of individual acid was larger in winter than in summer, and also was larger at night than in the daytime. In the same sample, individual diacid and ketocarboxylic acid had higher particulate phase occurrence (FP > 56% in summer), whereas unsaturated diacid had higher gaseous phase occurrence (FP

Hydrophilic Carotenoids: Surface Properties and Aggregation Behavior of the Potassium Salt of the Highly Unsaturated Diacid Norbixin

AbstractThe oft‐claimed ‘good’ water solubility of the food color norbixin (3) could not be confirmed. In contrast, the potassium salt 5 of norbixin formed suitable dispersions. The surface and aggregation properties of salt 5 were investigated and compared with other naturally occurring and synthetic hydrophilic carotenoids (Table).

Effects of Saturated Acids on Physical Properties of UPE Resins Prepared from Recycled PET Products

In this study, effects of saturated acids on physical properties, including hardness, impact strength, flexural properties and thermal properties, of unsaturated polyester or UPE resins prepared from recycled PET bottles and fabrics were investigated. PET was depolymerized by glycolysis reaction with the excess propylene glycol in the presence of zinc acetate as a catalyst. UPE resins were then synthesized by polyesterification of these glycolyzed products with maleic anhydride as an unsaturated diacid as well as succinic acid and adipic acid as a saturated diacid. With the addition of styrene monomer, UPEs were subsequently casted into specimens by crosslinking reaction using methyl ethyl ketone peroxide and cobalt octoate as an initiator and a catalyst, respectively. Physical properties of the cured specimens were then studied. The results showed that, when a saturated acid was incorporated, the hardness of the cured UPE resins decreased due to the decreasing amount of crosslinks. The extended distance between crosslinking sites on molecular chains facilitated load distribution, resulting in the significant improvement of impact strength. The flexural strength was also improved when the small amount of saturated acid was used. The onset thermal degradation temperatures and the glass transition temperatures of the prepared UPE resins were almost unchanged.

A Convenient Route to the Synthesis of Isotopomeric Dihydro-2(3H)furanones

A general synthetic procedure leading to isotopomeric dihydro-2(3H)furanones (gamma-butyrolactones) containing two, four, or six deuterium atoms has been developed. The labeled dihydro-2(3H)furanones were synthesized in quantitative yield from the saturated diacid C4 (succinic) or unsaturated diacids C4 (fumaric, maleic, or acetylendicarboxylic) in the presence of Ru4H4(CO)8(PBu3)4 using a deuterium pressure of 180 bar at 180 degrees C. This methodology was applied to the total synthesis of a hexadeuterated matairesinol lignan: The 3,4-bis[[3-methoxy-4-(phenylmethoxy)phenyl]methyl]dihydro-2(3H)furanone-[7,7',8,8',9',9'-D6] (benzyl-protected matairesinol-D6) was fully characterized.

Photochemical production and loss of organic acids in high Arctic aerosols during long-range transport and polar sunrise ozone depletion events

Abstract Unique daily measurements of water-soluble organics in fine ( 2 μm) aerosols were conducted at Alert in the Canadian Arctic in winter to spring of 1992. They yield insight into photochemical production and loss of organics during long-range transport and ozone depletion events following polar sunrise. Comprehensive analyses of α, ω-dicarboxylic acids (C2–C12), ω-oxocarboxylic acids (C2–C9) and α-dicarbonyls (C2, C3) as well as pyruvic acid and aromatic (phthalic) diacid were conducted using GC and GC/MS techniques. Oxalic (C2) acid was generally the dominant diacid species in both fine and coarse fractions, followed by malonic (C3) and succinic (C4) acids. Concentrations of total diacids in the fine aerosol fraction (0.2–64 ng m−3) were 5–60 times higher than those in the coarse fraction (0.01–3 ng m−3). After polar sunrise in early-March, the total concentration of fine aerosol diacids increased by a factor of 3–5 while the coarse mode did not change significantly. From dark winter to sunlit spring, temporal changes in correlations and ratios of these water-soluble organics to vanadium and sulfate measured simultaneously suggest that atmospheric diacids and related organic compounds are largely controlled by long-range atmospheric transport of polluted air during winter, but they are significantly affected by photochemical production. The latter can occur in sunlight either during transport to the Arctic or during photochemical events associated with surface ozone depletion and bromine chemistry near Alert in spring. Conversion of gaseous precursors to particulate matter via photochemical oxidation was intensified at polar sunrise, resulting in a peak in the ratio of total diacids to V. During ozone depletion events, complex patterns are indicated in photochemical production and loss depending on the diacid compound. Unsaturated (maleic and phthalic) diacids were inversely correlated with particulate Br whereas saturated diacids (C2–C4) positively correlated with particulate Br. These results suggest that Br chemistry associated with ozone depletion leads to degradation of unsaturated diacids and to the production of smaller saturated diacids.

Determination of stable carbon isotopic compositions of low molecular weight dicarboxylic acids and ketocarboxylic acids in atmospheric aerosol and snow samples.

We report a new method developed for the determination of stable carbon isotopic composition of homologous alpha,omega-dicarboxylic acids and phthalic acid isolated from environmental samples such as atmospheric aerosols and snow. Dicarboxylic acids are derivatized with BF3/1-butanol to dibutyl esters, which are analyzed for the stable carbon isotopic composition using a capillary GC interfaced to on-line combustion isotope ratio mass spectrometer. The delta13C values for individual dicarboxylic acid are then calculated from delta13C of 1-butanol and butyl ester derivative using a mass balance equation. The accuracy of the delta13C measurement for C2-C10 diacids is within 0.8 per thousand. We report a few examples of the delta13C ratios of saturated C2-C9 alpha,omega-dicarboxylic acids, unsaturated (maleic, phthalic) diacids, and oxocarboxylic acids in the aerosol and snow samples.

Spectroelectrochemical investigation of the adsorption and oxidation of unsaturated C 4-alcohols

The adsorption and oxidation of cis-2-butene-1,4-diol and 2-butyne-1,4-diol at gold and platinum electrodes have been investigated with in situ infrared and surface-enhanced Raman spectroscopy (SERS). SER-spectroscopic results indicate a strong interaction of the unsaturated bond with the gold surface, as evidenced by a strong shift of the stretching frequency of this bond to lower wavenumbers. In addition, an interaction of the OH groups with the electrode surface has been detected with in situ infrared spectroscopy. At platinum electrodes, the adsorbed molecules are partially decomposed, resulting in the formation of carbon monoxide and further molecular fragments. The oxidation of these molecules proceeds via aldehydes as intermediates, leading to carbon dioxide or carbonate as final products. Only in the case of oxidation of 2-butene-1,4-diol in alkaline solution is a stable anion of the unsaturated diacid (maleic acid) formed at both the gold and the platinum electrode in addition.