Dibutyl Fumarate Research Articles

Target Exposome for Characterizing Early Gestational Exposure to Contaminants of Emerging Concern and Association with Gestational Diabetes Mellitus.

Characterization of gestational exposure to complex contaminants of emerging concern (CECs) is critical to the identification of environmental risk factors for pregnancy complications. However, determination of various CECs with diverse physicochemical properties in biological fluids is technically challenging. In the present study, we developed a target exposome protocol, consisting of simple liquid-liquid extraction-based sample preparation and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, to determine 325 CECs covering 11 subclasses, including poly- and perfluoroalkyl substances, organophosphate esters, ultraviolet (UV) stabilizers, synthetic antioxidants, phthalate esters, and several others. The protocol exhibits exceptional advantages over traditional approaches in the coverage of chemicals, sample volume demand, and time and financial cost. The protocol was applied in a prospective nested gestational diabetes mellitus (GDM) study including 120 cases and 240 matched healthy controls. Thirty-three CECs were detected in >70% of the samples, with a combined concentration of 17.0-484.7 ng/mL. Bayesian kernel machine regression analysis showed that exposure to the CEC mixture was significantly associated with a higher GDM risk. For example, when increasing all CECs in the mixture from 50th percentile to 75th percentile, the estimated probit of GDM incidence had an increase of 92% (95% CI: 56%, 127%). Meanwhile, perfluorohexanesulfonic acid, 1,3-diphenylguanidine, and dibutyl fumarate were identified as the key CECs driving the joint effect. This work demonstrates great potential of our target exposome protocol for environmental risk factor identification in large-scale epidemiology or biomonitoring studies.

Gestational Exposure to Plastic Additives and Associations with Placental Function-Related Genes

Despite an increasing number of environmental reports on plastic additives, gestational exposure to these chemicals has been poorly characterized. The present work aimed to characterize gestational exposure to a total of 50 broadly used plasticizers and antioxidants in women with full-term (n = 155) and preterm deliveries (n = 75) and to explore the associations of prenatal exposure with the expressions of placental function-related genes. A few of them exhibited significantly different concentrations between the preterm and full-term deliveries group, including 2,6-di-tert-butyl-4-(dimethylamino-methyl)phenol (AO4703), dibutyl fumarate (DBF), tributyl citrate (TBC), triethyl citrate (TEC) 2,4-di-tert-butyl-phenol (2,4-DtBP), 2,4-(1,1,3,3-tetra-methylbutyl)phenol (4-tOP), 2,6-di-tert-butyl-4-hydroxytoluene (BHT), and their transformation products. Significant associations were determined between the concentrations of selected chemicals among the 14 substances with detection frequency greater than 60% and the mRNA expression levels of selected genes related to placental functions. The associations also exhibited chemical-specific patterns and significantly differed between preterm and full-term deliveries. Our work represents the first population-based study to assess potential links between gestational exposure to selected plasticizers and antioxidants and placental functions, calling for further efforts to elucidate the potential mechanisms and subsequent impacts on adverse pregnancy outcomes.

Prenatal Exposure to Emerging Plasticizers and Synthetic Antioxidants and Their Potency to Cross Human Placenta.

Gestational exposure to environmental chemicals and subsequent permeation through the placental barrier represents potential health risks to both pregnant women and their fetuses. In the present study, we explored prenatal exposure to a suite of 46 emerging plasticizers and synthetic antioxidants (including five transformation products of 2,6-di-tert-butyl-4-hydroxytoluene, BHT) and their potency to cross human placenta based on a total of 109 maternal and cord serum pairs. Most of these chemicals have rarely or never been investigated for prenatal exposure and associated health risks. Eleven of them exhibited detection frequency greater than 50% in maternal blood, including dibutyl fumarate (DBF), 2,6-di-tert-butylphenol (2,4-DtBP), 1,3-diphenylguanidine (DPG), methyl-2-(benzoyl)benzoate (MBB), triethyl citrate (TEC), BHT, and its five metabolites, with a median concentration from 0.05 to 3.1 ng/mL. The transplacental transfer efficiency (TTE) was determined for selected chemicals with valid measurements in more than 10 maternal/cord blood pairs, and the mean TTEs exhibited a large variation (i.e., 0.29-2.14) between chemicals. The determined TTEs for some of the target chemicals were comparable to the predicted values by our previously proposed models developed from molecular descriptors, indicating that their transplacental transfer potency could be largely affected by physicochemical properties and molecular structures. However, additional biological and physiological factors may influence the potency of environmental chemicals to cross human placenta. Overall, our study findings raise concern on human exposure to an increasing list of plastic additives during critical life stages (e.g., pregnancy) and potential health risks.

Green Routes toward Cross-Linkable and Robust Elastomers Derived from Biobased Fumaric Acid

In the rubber industry, the substitution of traditional engineering rubbers derived from fossil resources with novel biobased elastomers is considered for sustainable development, which largely relies on a straightforward and environmentally friendly synthesis procedure and the availability of material properties. In the research, semi-biobased elastomers, poly(dibutyl fumarate-co-butadiene)s (PDBFBs), were prepared by redox emulsion polymerization of dibutyl fumarate obtained from fumaric acid esterified with n-butanol and partially petroleum-derived butadiene. The microscopic structures of PDBFBs were verified by FTIR, NMR, and GPC analyses. The Tg values of PDBFBs were in the range of −73 and −58 °C. Additionally, the reactivity ratios of two comonomers in PDBFBs were evaluated by two methods: the Fineman–Ross and Kelen–Tüdös methods. The macroscopic properties of semi-biobased elastomers, such as thermal and mechanical performances, were meticulously regulated via molecular design. To achieve the desired properties, silica was incorporated into the PDBFBs to prepare strong nanocomposites. These nanocomposites displayed adequate tensile strength (14.3–31.6 MPa), adequate elongation at break (338–457%), low rolling resistance, and excellent thermoresistant oxygen aging performance. These results showed that PDBFB nanocomposites possessed quite good properties and had the potential for practical applications. This work provides a facile, efficient, solvent-less green synthesis route to design new-generation promising sustainable engineering elastomers for the rubber industry.

Mechanical and thermal properties of poly(lactic acid) plasticized with dibutyl maleate and fumarate isomers: Promising alternatives as biodegradable plasticizers

The use of plasticizers, polymer blends and composites have been reported as effective strategies to overcome the rigidity and brittleness of PLA, drawbacks that commonly limits its application. In this study poly(lactic acid) was plasticized with 7 and 12 wt% of dibutyl esters of maleic or fumaric acid. The choice of plasticizer was motivated by recent studies reporting the biodegradability of maleic and fumaric esters and their efficiency as green plasticizers. This current study evaluates how the chemical structure, specifically the cis–trans isomerism of the plasticizer, can affect the plasticizing properties on PLA. The thermal and mechanical properties of the plasticized specimens were evaluated by DSC, DMA, Stress-Strain and Relaxation tests. The results indicated that samples plasticized with dibutyl fumarate exhibited a lower glass transition temperature (Tg), lower Young’s modulus, and higher elongation at break than specimens plasticized with dibutyl maleate.

Single‐Site Molybdenum Catalyst for the Synthesis of Fumarate

AbstractThe catalysts with well‐defined mononuclear active sites are expected to develop more active catalytic systems for the key chemical transformations. But the rational design of catalyst with stable mononuclear Mo site is still a crucial challenge because of its oligomerization tendency under reaction condition. Herein, Molybdenum catalyst (Mo‐8‐HQ) with single Mo sites was designed via the pyridine nitrogen and oxygen in hydroxyl of 8‐hydroxyquinoline coordinated with Mo atom. The crystal catalyst was stabilized by π‐π stacking interaction and hydrogen bonds to form isolated Mo specie. The single‐site molybdenum catalyst exhibited excellent catalytic performance in didehydroxylation reactions with high selectively of dibutyl fumarate (86 %) product at mild reaction condition. Deuterium isotopic studies demonstrated that the mechanism feature of didehydroxylation reaction catalyzed by Mo‐8‐HQ was through concerted cleavage of two C−O bonds process, which could be accelerated by single‐site molybdenum catalysts with electron‐rich Mo centers.

Production of Plant Phthalate and its Hydrogenated Derivative from Bio-Based Platform Chemicals.

Direct transformation of bio-based platform chemicals into aromatic dicarboxylic acids and their derivatives, which are widely used for the manufacture of polymers, is of significant importance for the sustainable development of the plastics industry. However, limited successful chemical processes have been reported. This study concerns a sustainable route for the production of phthalate and its hydrogenated derivative from bio-based malic acid and erythritol. The key Diels-Alder reaction is applied to build a substituted cyclohexene structure. The dehydration reaction of malic acid affords fumaric acid with 96.6 % yield, which could be used as the dienophile, and 1,3-butadiene generated in situ through erythritol deoxydehydration serves as the diene. Starting from erythritol and dibutyl fumarate, a 74.3 % yield of dibutyl trans-4-cyclohexene-1,2-dicarboxylate is obtained. The palladium-catalyzed dehydrogenation of the cycloadduct gives a 77.8 % yield of dibutyl phthalate. Dibutyl trans-cyclohexane-1,2-dicarboxylate could be formed in nearly 100 % yield under mild conditions by hydrogenation of the cycloadduct. Furthermore, fumaric acid and fumarate, with trans configurations, were found to be better dienophiles for this Diels-Alder reaction than maleic acid and maleate, with cis configuration, based on the experimental and computational results. This new route will pave the way for the production of environmental friendly plastic materials from plants.

Post-polymerization modification of unsaturated polyesters by Michael addition of N-heterocyclic carbenes

The post-polymerization modification of unsaturated polyesters, three polymaleates and a polyfumarate, was performed by the Michael addition of N-heterocyclic carbenes (NHCs) to produce thermally stable unsaturated polyesters. The model reactions of NHCs, 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene (TPT), and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IDipp), with dibutyl fumarate and dibutyl maleate selectively proceeded to give the corresponding Michael adducts, whereas 1,3-di-tert-butylimidazol-2-ylidene (ItBu) exclusively catalyzed the isomerization of dibutyl maleate. Based on these results, reactions of the unsaturated polyesters with TPT and IDipp were investigated. The polyesters bearing NHCs as side chains were obtained in good-to-high yields. The number of NHC-incorporated units can be controlled by the amount of added NHCs, and the obtained polyesters showed better solubility in common organic solvents. It is noteworthy that the glass transition temperatures (Tgs) were widely tunable and increased linearly with increasing NHC content because of the stiff and bulky structure. In addition, reactions of the unsaturated polyesters with TPT in the presence of water allowed Michael addition and transfer hydrogenation to occur simultaneously. Radical cross-linking of the NHC-incorporated unsaturated polyesters with styrene produced thermally stable and fully miscible polyester resins. The Michael addition of N-heterocyclic carbenes (NHCs) to the unsaturated polyesters, polymaleates and a polyfumarate, produced the polymers bearing the NHCs as side chains in good-to-high yields. The glass transition temperatures of the obtained polymers were widely tunable and increased linearly with the increasing NHC content. The stiff and bulky structures of the NHCs can reduce the mobility of the polymer main chain. The simultaneous Michael addition and transfer hydrogenation of the unsaturated polyesters have also been performed by the reaction with an NHC in the presence of water.

The emissions and the performance of diethyl succinate in a diesel fuel blend

The finite natures of fossil fuels and their contributions to anthropogenic climate change are driving the development of biofuels. However, because of the inherent issues with current biofuels, such as ethanol and biodiesel, innovative replacements are being increasingly sought. Recently, four esters produced from fermentation, namley diethyl succinate, dibutyl succinate, dibutyl fumarate and dibutyl malonate, were reported to have suitable physical properties as a substitute for conventional diesel fuel. Although the physical properties are indicative of the fuel behaviour, the determination of the combustion emissions and the performance of a fuel using controlled engine testing is vital. In this investigation, the engine performance and emissions produced from the most viable fuel, namely diethyl succinate, were examined. Diethyl succinate was blended with diesel in a 20 vol % blend, owing to the low cetane number of diethyl succinate, and the emissions established in pseudo-steady-state conditions using a 2.0 L turbocharged direct-injection EURO 3-compliant light commercial vehicle equipped with a direct-injection common-rail diesel engine. When using the diesel–20 vol % diethyl succinate blend, the fuel demand and the wheel force were higher for the majority of engine speeds than those of diesel, whereas the exhaust gas temperatures were lower. The difference between the exhaust gas temperature for the diesel–20 vol % diethyl succinate blend and that for diesel increased with increasing pedal demand. In comparison with the carbon monoxide emissions from petroleum-derived diesel, the carbon monoxide emissions obtained when using the diesel–20 vol % diethyl succinate blend were reduced, most probably because of more complete combustion due to the increased oxygen content. However, the total hydrocarbon emissions and the mono-nitrogen oxide emissions were shown to increase on using the diethyl succinate blend. Both of these factors were presumably due to the lower cetane number of the fuel, although the increase in the total hydrocarbon emissions was deemed negligible because of the low amount produced by both fuels.

Dibutyl Maleate and Dibutyl Fumarate Enhance Contact Sensitization to Fluorescein Isothiocyanate in Mice.

Di-n-butyl phthalate (DBP), a phthalate ester, has been shown to have an adjuvant effect on fluorescein isothiocyanate (FITC)-induced contact hypersensitivity (CHS) mouse models. Di-n-butyl maleate (DBM), widely used as a plasticizer for industrial application, has been reported to cause dermatitis in humans. DBM is a butyl alcohol ester of di-carboxylic acid that represents a part of the DBP structure, while di-n-butyl fumarate (DBF) is a trans isomer of DBM. We examined whether DBM or DBF exhibits an adjuvant effect like DBP does. When BALB/c mice were epicutaneously sensitized with FITC in the presence of DBM or DBF, the FITC-specific CHS response was enhanced, as we have observed for DBP. As to underlying mechanisms, DBM and DBF facilitated the trafficking of FITC-presenting CD11c(+) dendritic cells (DCs) from skin to draining lymph nodes and increased the cytokine production by draining lymph nodes. In conclusion, DBM and DBF may have an effect that aggravates contact dermatitis through a skin sensitization process.

Synthesis and crystal structure of a molybdenum complex of fullerene, [Mo(η2–C60)(CO)2(dpphen)(dbf)·0.63CS2] (dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutyl fumarate)

The molybdenum complex [Mo(η2-C60)(CO)2(dpphen)(dbf)] (1) [dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutyl fumarate] has been prepared and structurally characterized by X-ray diffraction analysis. In the molecule of (1), the coordination geometry of the Mo atom is distorted octahedral with the phen (1,10-phenanthroline) group of dpphen and two CO groups in the equatorial plane. The Mo atom binds in an η2-fashion to the C—C bonds of C60and dbf. The two C—C bonds are almost mutually orthogonal.

Hydrophobic Effects in 1,3-Dipolar Cycloaddition of C,N-Diphenylnitrone with Dibutyl fumarate in Aqueous Solutions

The reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with dibutylfumarate increases dramatically in aqueous solutions relative to other solvents.

Hydrophobic Effects in 1,3-Dipolar Cycloaddition of C,N-Diphenylnitrone with Dibutyl fumarate in Aqueous Solutions

The reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with dibutylfumarate increases dramatically in aqueous solutions relative to other solvents.

Kinetic and electron paramagnetic resonance studies on radical polymerization. Radical copolymerization of p‐tert‐butoxy‐styrene and dibutyl fumarate in benzene

AbstractThe copolymerization of p‐tert‐butoxystyrene (1) (M1) and dibutyl fumarate (2) (M2) initiated with dimethyl 2,2′‐azobisisobutyrate (3) was studied in benzene at 60°C kinetically and by means of electron paramagnetic resonance (EPR) spectroscopy. The monomer reactivity ratios were determined to be r1 = 0,18 and r2 = 0,01, indicating that homopropagation of M2 is almost negligible in the copolymerization. The copolymerization system was revealed to involve EPR‐observable propagating polymer radicals under practical copolymerization conditions. The apparent rate constants of propagation (kp) and termination (kt) determined by EPR show a rapid increase in the range from 0,9 to 1,0 of feed composition (f1 = {[M1]/([M1] + [M2])}) of M1. From the relationship between kp and f1 based on Fukuda's penultimate model, the rate constants of propagation of copolymerization were evaluated; k111 = 140 L · mol−1 · s−1, k211 = 4,3 L · mol−1 · s−1, k112 = 778 L · mol−1 · s−1, k212 = 24 L · mol−1 s−1 and k121 = 19 L · mol−1 · s−1, suggesting a pronounced penultimate effect.

Oxidative copolymerization of vinyl monomers with fumarates

The kinetic parameters of the oxidative copolymerization of styrene, butyl methacrylate and butyl acrylate with dibutyl fumarate have been found. The mechanism of the process is examined and the influence of the nature of the monomer on the length of the material chains of the polyperoxides formed is established. The special aspects of the course of oxidative polymerization in real systems based on oligoester maleates have been analysed. Recommendations are made to lessen oxygen inhibition of curing of oligomer-monomer composites.

Some peculiarities of the copolymerization of maleates and fumarates with styrene and butyl methacrylate in the presence of oxygen

A study has been made of the copolymerization of styrene and butyl methacrylate with diethyl maleate and dibutyl furmarate in the presence of oxygen. It is shown that diethyl maleate and dibutyl fumarate participate in oxidative copolymerization not as comonomers, but as chain transfer agents. This is attributed to features of the mechanisms of oxidative homopolymerization of these compounds.

Maleinsäure- und fumarsäureester als liganden in metallcarbonyl-komplexen: II. Gemischte dicarbonyl- und tricarbonyl-komplexe des molybdäns mit maleinsäure- und fumarsäureestern und zweizähnigen n-liganden

The binuclear complexes [Mo(CO) 3L 2] 2 (L &2.dbnd; maleic acid or fumaric acid esters) react with the N-heterocyclics 2,2'-bipyridine (Bipy) or 1,10-phenanthroline (Phen) under elimination of CO giving the mononuclear dicarbonyl compounds Mo(CO) 2QL 2 (Q &2.dbnd; Bipy, Phen) with cis3-carbonyl ligands: [Mo(CO) 3L 2] 2 + 2 Q - 2 Mo(CO) 2QL 2 + 2 CO In the reaction of Phen together with fumaric acid esters with C 7H 8Mo(CO) 3, tricarbonyl complexes with a meridional arrangement of the CO ligands are formed: C 7H 8Mo(CO) 3 + Phen + L → mer-Mo(CO) 3PhenL + C 7-H 8 In the case of the dibutyl fumarate derivative (L &2.dbnd; DBFU), isomerization to the facial CO arrangement is effected by a small excess of the ester: ▪ In solution the mer-Mo(CO) 3PhenL complexes slowly undergo carbonyl disproportionation: ▪ Possible mechanisms for these reactions are discussed.

The effect of conversion on the copolymerization of ethylene and dibutyl fumarate

Journal of Polymer Science Part A: General PapersVolume 3, Issue 11 p. 3977-3978 Note The effect of conversion on the copolymerization of ethylene and dibutyl fumarate R. Roberts, R. Roberts Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this authorR. D. Lundberg, R. D. Lundberg Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this authorN. L. Zutty, N. L. Zutty Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this author R. Roberts, R. Roberts Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this authorR. D. Lundberg, R. D. Lundberg Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this authorN. L. Zutty, N. L. Zutty Research and Development Department Union Carbide Corporation, Plastics Division South Charleston, West VirginiaSearch for more papers by this author First published: November 1965 https://doi.org/10.1002/pol.1965.100031129AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume3, Issue11November 1965Pages 3977-3978 RelatedInformation