Showing papers on "Terephthalic acid published in 2018"
TL;DR: Based on structural and site-directed mutagenesis experiments, the detailed process of PET degradation into MHET, terephthalic acid, and ethylene glycol is suggested and other PETase candidates potentially having high PET-degrading activities are suggested based on phylogenetic tree analysis of 69 PETase-like proteins.
Abstract: Plastics, including poly(ethylene terephthalate) (PET), possess many desirable characteristics and thus are widely used in daily life However, non-biodegradability, once thought to be an advantage offered by plastics, is causing major environmental problem Recently, a PET-degrading bacterium, Ideonella sakaiensis, was identified and suggested for possible use in degradation and/or recycling of PET However, the molecular mechanism of PET degradation is not known Here we report the crystal structure of I sakaiensis PETase (IsPETase) at 15 A resolution IsPETase has a Ser–His-Asp catalytic triad at its active site and contains an optimal substrate binding site to accommodate four monohydroxyethyl terephthalate (MHET) moieties of PET Based on structural and site-directed mutagenesis experiments, the detailed process of PET degradation into MHET, terephthalic acid, and ethylene glycol is suggested Moreover, other PETase candidates potentially having high PET-degrading activities are suggested based on phylogenetic tree analysis of 69 PETase-like proteins
359 citations
TL;DR: This work reports a process for converting fructose to 2,5-furandicarboxylic acid (FDCA), a monomer used in the production of polyethylene furanoate, a renewable plastic, that is economically competitive with current terephthalic acid processes.
Abstract: We report a process for converting fructose, at a high concentration (15 weight %), to 2,5-furandicarboxylic acid (FDCA), a monomer used in the production of polyethylene furanoate, a renewable plastic. In our process, fructose is dehydrated to hydroxymethylfurfural (HMF) at high yields (70%) using a γ-valerolactone (GVL)/H2O solvent system. HMF is subsequently oxidized to FDCA over a Pt/C catalyst with 93% yield. The advantage of our system is the higher solubility of FDCA in GVL/H2O, which allows oxidation at high concentrations using a heterogeneous catalyst that eliminates the need for a homogeneous base. In addition, FDCA can be separated from the GVL/H2O solvent system by crystallization to obtain >99% pure FDCA. Our process eliminates the use of corrosive acids, because FDCA is an effective catalyst for fructose dehydration, leading to improved economic and environmental impact of the process. Our techno-economic model indicates that the overall process is economically competitive with current terephthalic acid processes.
253 citations
TL;DR: In this paper, electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-Furandicarboxylic acid (FDCA) was demonstrated using Cu, one of the cheapest transition metals, as the catalytic anode.
Abstract: 2,5-Furandicarboxylic acid (FDCA) is a key near-market platform chemical that can potentially replace terephthalic acid in various polyesters such as polyethylene terephthalate (PET). FDCA can be obtained from oxidation of 5-hydroxymethylfurfural (HMF), which can be derived from cellulosic biomass through isomerization and dehydration of hexoses. In this study, electrochemical oxidation of HMF to FDCA is demonstrated using Cu, one of the cheapest transition metals, as the catalytic anode. The oxidized Cu surface is not catalytic for water oxidation, which is the major reaction competing with HMF oxidation in aqueous media. Therefore, a wide potential window to oxidize HMF without inducing water oxidation was available, enabling high Faradaic efficiencies for FDCA production. Cu was prepared as nanocrystalline and bulk electrodes by electrodeposition, and key differences in their surface oxidation and electrochemical HMF oxidation were investigated. The oxide and hydroxide layers formed on the nanocrystall...
181 citations
TL;DR: These findings open the door to valorize lignin, the second most abundant polymer on earth, by metabolically engineered C. glutamicum for industrial production of MA and potentially other chemicals.
Abstract: Cis, cis-muconic acid (MA) is a dicarboxylic acid of recognized industrial value. It provides direct access to adipic acid and terephthalic acid, prominent monomers of commercial plastics. In the present work, we engineered the soil bacterium Corynebacterium glutamicum into a stable genome-based cell factory for high-level production of bio-based MA from aromatics and lignin hydrolysates. The elimination of muconate cycloisomerase (catB) in the catechol branch of the β-ketoadipate pathway provided a mutant, which accumulated MA at 100% molar yield from catechol, phenol, and benzoic acid, using glucose as additional growth substrate. The production of MA was optimized by constitutive overexpression of catA, which increased the activity of the encoded catechol 1,2-dioxygenase, forming MA from catechol, tenfold. Intracellular levels of catechol were more than 30-fold lower than extracellular levels, minimizing toxicity, but still saturating the high affinity CatA enzyme. In a fed-batch process, the created strain C. glutamicum MA-2 accumulated 85 g L−1 MA from catechol in 60 h and achieved a maximum volumetric productivity of 2.4 g L−1 h−1. The strain was furthermore used to demonstrate the production of MA from lignin in a cascade process. Following hydrothermal depolymerization of softwood lignin into small aromatics, the MA-2 strain accumulated 1.8 g L−1 MA from the obtained hydrolysate. Our findings open the door to valorize lignin, the second most abundant polymer on earth, by metabolically engineered C. glutamicum for industrial production of MA and potentially other chemicals.
142 citations
TL;DR: Electrochemical oxidation in acidic media offers a new pathway to convert 5-hydroxymethylfurfural into maleic acid, which is another desirable biomass-derived platform molecule.
Abstract: 2,5-Furandicarboxylic acid (FDCA) has become an increasingly desirable platform chemical to replace terephthalic acid in the production of a variety of polymeric materials, including polyethylene terephthalate. FDCA can be produced by the oxidation of 5-hydroxymethylfurfural (HMF), which can be derived from cellulosic biomass. Oxidation of HMF to FDCA is typically performed under basic conditions. Separation of FDCA is most easily accomplished by lowering the pH until FDCA is insoluble and filtering it from solution. In a large-scale process, this would lead to a high operating cost to purchase the required acid and base and to dispose of the resulting salt waste. In this study, electrochemical oxidation of HMF was carried out in acidic media by using a manganese oxide (MnOx ) anode to remove the need to vary the pH to separate FDCA. The MnOx anode afforded a FDCA yield of 53.8 % in a pH 1 H2 SO4 solution, in which FDCA precipitation occurred spontaneously from the same reaction solution without altering the pH or other aspects of the solution composition. Electrochemical oxidation in acidic media offers a new pathway to convert HMF into maleic acid, which is another desirable biomass-derived platform molecule. The performance of the MnOx anode was investigated in comparison with that of a Pt anode to identify unique electrocatalytic properties of the MnOx anode for HMF oxidation.
112 citations
TL;DR: In this article, a hexagonal ZnO thin film was successfully synthesized by chemical spray pyrolysis technique for detecting CO2 gas and getting maximum response for operating temperature of 350°C and response and recovery time periods are 75 and 108
Abstract: A hexagonal ZnO thin films have been successfully synthesized by chemical spray pyrolysis technique. Photoelectrocatalytic activity of ZnO photoelectrode is tested for photoelectrocatalytic degradation of terephthalic acid as a model organic pollutant. The degradation percentage of terephthalic acid using ZnO photoelectrode has reached up to 91% under ultraviolet illumination after 400 min. ZnO thin films are used for detecting CO2 gas and getting maximum response for operating temperature of 350 °C and response and recovery time periods are 75 and 108 s, respectively for 400 ppm CO2 gas concentration. ZnO sensor has good repeatability along with a quick response time. Thus a multifunctional ZnO thin film is the potential candidate for both for photocatalytic and CO2 gas sensing applications.
99 citations
TL;DR: It is shown that the physical-chemical properties of the MOF depend on whether the functionalisation occurs at defective sites or on the framework, and that the defects had missing-cluster nature.
Abstract: Post-synthetic ligand exchange in the prototypical zirconium-based metal-organic framework (MOF) UiO-66 was investigated by in situ solution 1 H NMR spectroscopy. Samples of UiO-66 having different degrees of defectivity were exchanged using solutions of several terephthalic acid analogues in a range of conditions. Linker exchange only occurred in defect-free UiO-66, whereas monocarboxylates grafted at defect sites were found to be preferentially exchanged with respect to terephthalic acid over the whole range of conditions investigated. A 1:1 exchange ratio between the terephthalic acid analogue and modulator was observed, providing evidence that the defects had missing-cluster nature. Ex situ characterisation of the MOF powders after exchange corroborated these findings and showed that the physical-chemical properties of the MOF depend on whether the functionalisation occurs at defective sites or on the framework.
94 citations
TL;DR: In this paper, the authors reported the hydrothermal synthesis of an Fe-MOF nanosheet array on nickel foam using aqueous Fe3+ and terephthalic acid as precursors.
Abstract: It is highly desired to develop high-performance non-noble-metal electrocatalysts for the oxygen evolution reaction (OER) in alkaline solutions. In this communication, we report the hydrothermal synthesis of an Fe-MOF nanosheet array on nickel foam (Fe-MOF/NF) using aqueous Fe3+ and terephthalic acid as precursors. Such an Fe-MOF/NF shows superior electrocatalytic performance towards the OER in 1.0 M KOH with a low overpotential of 240 mV at 50 mA cm−2 and a small Tafel slope of 72 mV dec−1. Notably, this catalyst also exhibits high long-term electrochemical durability to maintain its activity for at least 30 h. Moreover, this catalyst electrode achieves a high turnover frequency of 0.74 mol O2 per s at an overpotential of 300 mV.
91 citations
TL;DR: The presented results indicate that the properties of UiO-66 are changing considerably in aqueous media under common conditions used for organophosphate degradations, and therefore its catalytic activity is not related to the number of structural defects created during the material synthesis.
Abstract: Zirconium-based metal-organic frameworks were recently investigated as catalysts for degradation of organophosphate toxic compounds, such as pesticides or chemical warfare agents. The most utilized UiO-66 is considered as a stable material for these applications in an aqueous environment. However, the presented results indicate that the properties of UiO-66 are changing considerably in aqueous media under common conditions used for organophosphate degradations, and therefore its catalytic activity is not related to the number of structural defects created during the material synthesis. We delineate the stability of UiO-66 in water of various pHs, the in situ formation of new catalytic sites, and the correlation of these two parameters with the degradation rate of a model organophosphate pollutant, dimethyl-4-nitrophenyl phosphate (methyl-paraoxon). The stability was quantified using high-performance liquid chromatography (HPLC) by measuring the amounts of leached terephthalic acid, the linker of UiO-66, and monocarboxylic acids, the modulators bound at UiO-66 defects. We demonstrate that the HPLC analysis is a more suitable method for metal-organic frameworks stability assessment than commonly used methods, e.g., powder X-ray diffraction, adsorption isotherms, or electron microscopy.
82 citations
TL;DR: In this article, the effect of crosslinker geometry on the properties of PVA is reported, where aliphatic (suberic) and aromatic (terephthalic) dicarboxylic acids are used as crosslinkers.
Abstract: In the presented work, the effect of crosslinker geometry on the properties of PVA is reported. The aliphatic (suberic) and aromatic (terephthalic) dicarboxylic acids are used as crosslinker molecules. On the basis of tensile test and thermal properties, it is observed that crosslinking of PVA by suberic acid is more effective than terephthalic acid. The maximum strength measured in crosslinked samples is 32.5 MPa for suberic acid crosslinked PVA which is higher than that of neat PVA (22.6 MPa). Swelling study shows that 8 h crosslinked terephthalic acid (35% w/w) samples have a minimum of 5.4% of water uptake compared to neat PVA, which dissolves readily in water. DTGA shows that the decomposition temperature of crosslinked PVA is 345 °C while neat PVA has a decomposition temperature of 315 °C. FTIR spectroscopy confirms the formation of crosslink ester bond in crosslinked PVA. The crosslinked samples kept for bio-degradation show maximum degradation in terephthalic acid (15% w/w) crosslinked PVA.
81 citations
TL;DR: It was found that compound 4 not only detected nitrobenzene derivatives-based explosives with high selectivity, sensitivity, and recyclability, but also served as an excellent selective sensing material for Fe3+ ion and Cr2O72- ion.
Abstract: Five novel Ln-MOFs associated with the mixed ligands of 4-(pyridin-3-yloxy)-phthalic acid (H2ppda) and terephthalic acid (H2bdc), namely, [Ln(ppda)(bdc)0.5(C2H5OH)(H2O)]n (Ln = Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)) were synthesized under the solvothermal conditions. Compounds 1–5 exhibit the isostructural 2D layered structures. The solid-state luminescence properties of compounds 1, 2, 4 and 5 were investigated in detail. It was found that compound 4 not only detected nitrobenzene derivatives-based explosives with high selectivity, sensitivity, and recyclability, but also served as an excellent selective sensing material for Fe3+ ion and Cr2O72− ion. In particular, it is worth noting that the detection limit of TNP can reach 3.0 × 10−8 M. It was found that the free oxygen atoms of the ether bond, which function as the Lewis basic sites in Ln-MOFs, might interact with metal ions. In addition, the sensing mechanisms of 4 for different analytes were explored further.
09 Jan 2018
TL;DR: An oxidase-like reaction is proposed for heme-containing peroxidases, such as UPO, horseradish peroxIDase, or catalase, causing the conversion of 5-formyl-2-furancarboxylic acid into FDCA in the absence of exogenous hydrogen peroxide.
Abstract: Enzymatic oxidation of 5-hydroxymethylfurfural (HMF) and its oxidized derivatives was studied using three fungal enzymes: wild-type aryl alcohol oxidase (AAO) from three fungal species, wild-type peroxygenase from Agrocybe aegerita (AaeUPO), and recombinant galactose oxidase (GAO). The effect of pH on different reaction steps was evaluated and apparent kinetic data (Michaelis-Menten constants, turnover numbers, specific constants) were calculated for different enzyme-substrate ratios and enzyme combinations. Finally, the target product, 2,5-furandicarboxylic acid (FDCA), was prepared in a multi-enzyme cascade reaction combining three fungal oxidoreductases at micro-scale. Furthermore, an oxidase-like reaction is proposed for heme-containing peroxidases, such as UPO, horseradish peroxidase, or catalase, causing the conversion of 5-formyl-2-furancarboxylic acid into FDCA in the absence of exogenous hydrogen peroxide.
TL;DR: This review highlights recent advances in the development of efficient catalytic systems and new strategies for the selective conversion of cellulose or its derived carbohydrates into functionalized organic acids.
Abstract: Cellulose is a promising renewable and abundant resource for the production of high-value chemicals, in particular, organic oxygenates, because of its high oxygen/carbon ratio. The sustainable production of hydroxycarboxylic acids and dicarboxylic acids, such as gluconic/glucaric acid, lactic acid, 2,5-furandicarboxylic acid, adipic acid, and terephthalic acid, most of which are monomers of key polymers, have attracted much attention in recent years. The synthesis of these organic acids from cellulose generally involves several tandem reaction steps, and thus, multifunctional catalysts that can catalyze the selective activation of specific C-O or C-C bonds hold the key. This review highlights recent advances in the development of efficient catalytic systems and new strategies for the selective conversion of cellulose or its derived carbohydrates into functionalized organic acids. The reaction mechanism is discussed to offer deep insights into the regioselective cleavage of C-O or C-C bonds.
TL;DR: The use of high resolution mass spectrometry allowed the structural elucidation of these compounds and their correct identification and showed that the oligomers with the highest concentration values were dimers and trimers, cyclic, as well as lineal, from the first and second series.
Abstract: An oligomer is a molecule that consists of a few monomer units. It can be formed during polymer manufacturing and also due to polymer degradation processes or even during use conditions. Since oligomers are not included in chemical databases, their identification is a complex process. In this work, the oligomers present in 20 different PET pellet samples have been determined. Two different sample treatment procedures, solvent extraction and total dissolution, were applied in order to select the most efficient one. The analyses were carried out by UPLC-MS-QTOF. The use of high resolution mass spectrometry allowed the structural elucidation of these compounds and their correct identification. The main oligomers identified were cyclic as well as lineal from the first, second, and third series. All of them were composed of terephthalic acid (TPA), diethylene glycol (DEG), and ethylene glycol (EG). Quantitative values were very different in both procedures. In total dissolution of PET samples, the concentration of oligomers was always, at least, 10 times higher than in solvent extraction; some of the compounds were only detected when total dissolution was used. Results showed that the oligomers with the highest concentration values were dimers and trimers, cyclic, as well as lineal, from the first and second series. The oligomer with the maximum concentration value was TPA2-EG-DEG that was found in all the samples in a concentration range from 2493 to 19,290 ng/g PET. No differences between virgin and recycled PET were found. Migration experiments were performed in two PET bottles, and results showed the transference of most of these oligomers to a fat food simulant (ethanol 95%).
TL;DR: B bisguaiacol (BG), a lignin-derived bisphenol analogue, can be used to prepare biobased polyesters with remarkable thermal properties, indicating that these new polyesters represent promising renewable and biodegradable alternatives to petroleum-based polyesters currently employed in the plastics industry.
Abstract: The utilization of wood-derived building blocks (xylochemicals) to replace fossil-based precursors is an attractive research subject of modern polymer science. Here, we demonstrate that bisguaiacol (BG), a lignin-derived bisphenol analogue, can be used to prepare biobased polyesters with remarkable thermal properties. BG was treated with different activated diacids to investigate the effect of co-monomer structures on the physical properties of the products. Namely, derivatives of adipic acid, succinic acid, and 2,5-furandicarboxylic acid were used. Moreover, a terephthalic acid derivative was used for comparison purposes. The products were characterized by 1 H NMR spectroscopy, attenuated total reflectance FTIR spectroscopy, gel-permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry to assess their structural and thermal properties in detail. The polymers showed glass-transition temperatures ranging up to 160 °C and thermal stabilities in excess of 300 °C. Furthermore, the susceptibility of the polyester to enzymatic hydrolysis was investigated to assess the potential for further surface functionalization and/or recycling and biodegradation. Indeed, hydrolysis with two different enzymes from the bacteria Thermobifida cellulosilytica led to the release of monomers, as quantified by HPLC. The results of this study indicate that our new polyesters represent promising renewable and biodegradable alternatives to petroleum-based polyesters currently employed in the plastics industry, specifically for applications in which high-temperature stability is essential to ensure overall system integrity.
TL;DR: A low-cost and biocompatible ionic liquid, cholinium phosphate, is demonstrated for the first time to play bifunctional roles in the solubilization and glycolytic degradation of PET and opens up avenues for exploring environmentally benign and efficient IL technology for Solubilizing and recycling postconsumer polyester plastics.
Abstract: The solubilization and efficient upgrading of high loadings of polyethylene terephthalate (PET) are important challenges, and most solvents for PET are highly toxic. Herein, a low-cost (ca. $1.2 kg) and biocompatible ionic liquid (IL), cholinium phosphate ([Ch][PO]), is demonstrated for the first time to play bifunctional roles in the solubilization and glycolytic degradation of PET. A high loading of PET (10 wt %) was readily dissolved in [Ch][PO] at relatively low temperatures (120 °C, 3 h) and under water-rich conditions. In-depth analysis of the solution revealed that high PET solubilization in [Ch][PO] could be ascribed to significant PET depolymerization. Acid precipitation yielded terephthalic acid as the dominant depolymerized monomer with a theoretical yield of approximately 95 %. Further exploration showed that in the presence of ethylene glycol (EG), the [Ch][PO]-catalyzed glycolysis of PET could efficiently occur with approximately 100 % conversion of PET and approximately 60.6 % yield of bis(2-hydroxyethyl)terephthalate under metal-free conditions. The IL could be reused at least three times without an apparent decrease in activity. NMR spectroscopy analysis revealed that strong hydrogen-bonding interactions between EG and the IL played an important role in the activation of EG and promotion of the glycolysis reaction. This study opens up avenues for exploring environmentally benign and efficient IL technology for solubilizing and recycling postconsumer polyester plastics.
TL;DR: In this article, a new porous metal-organic framework with chemical formula of [Cd3(cpota)2(phen)3]n·5nH2O (MOF-1) (H3cpota = 2-(4-carboxyphenoxy)terephthalic acid & phen = 1,10-phenanthroline) has been synthesized and characterized by infrared spectroscopy, elemental analysis, thermogravimetry and X-ray single crystal and powder diffracting methods.
Abstract: A new porous metal–organic framework with chemical formula of [Cd3(cpota)2(phen)3]n·5nH2O (MOF-1) (H3cpota = 2-(4-carboxyphenoxy)terephthalic acid & phen = 1,10-phenanthroline) has been synthesized and characterized by infrared spectroscopy, elemental analysis, thermogravimetry and X-ray single crystal and powder diffracting methods. MOF-1, as a potential material of the sensing applications, has an uncommon 3D microporous structure in which the trinuclear [Cd3(phen)3(μ2-COO)4]2+ SBUs are interconnected by the V-shaped cpota3− ligands. MOF-1 has good stabilities not only in aqueous solution in the range of pH = 1.0 ∼ 14.0 but also in solid from room temperature (RT) to 330 °C. Fluorescence titration, cyclic and anti-interference experiments demonstrate that MOF-1 is an excellent probe for volatile organic ketones (acetone/2-butanone) and hexavalent chromate (CrO42−/Cr2O72−) in aqueous solution. The luminescence investigations in the aqueous solution of pH = 9 reveal that the MOF-1 can efficiently and selectively detect Cr(VI) ions without the interference of other metal cations. Quenching mechanisms are also studied in detail.
TL;DR: In this paper, a permanganate was activated by ultraviolet (UV) photolysis at 254 nm, resulting in the efficient degradation of micropollutants, such as nitrobenzene, benzoic acid, terephthalic acid and nalidixic acid.
Abstract: Permanganate was activated by ultraviolet (UV) photolysis at 254 nm, resulting in the efficient degradation of micropollutants. The degradation of four probe molecules (i.e., nitrobenzene, benzoic acid, terephthalic acid, and p-chlorobenzoic acid) and two micropollutants (i.e., gemfibrozil and nalidixic acid) resistant to permanganate oxidation was enhanced by the UV/permanganate system, with pseudo-first-order rate constants (k′) of 0.065–0.678 min–1 under the experimental conditions. Hydroxyl radicals (HO•) and Mn(V) peroxide, which were produced during the activation of permanganate by UV irradiation, were responsible for the enhancement. The quantum yield of HO• was 0.025 ± 0.001 mol Einstein–1 (mol Es–1) in the system. HO• oxidation primarily accounted for the degradation of nitrobenzene and gemfibrozil, while both HO• and Mn(V) were responsible for the degradation of benzoic acid, terephthalic acid, p-chlorobenzoic acid, and nalidixic acid. This study is the first report on the activation of permang...
TL;DR: Three new Al-MOFs in the formation of BIT-72, BIT-73 and BIT-74 have been synthesized by assembling Al3+ ion with terephthalic acid ions decorated with monohydroxyl, monomethyl or dimethyl groups, respectively, and exhibit high stability in boiling water and acidic conditions.
Abstract: Three new Al-MOFs in the formation of [Al4(OH)2(OCH3)4(OH-BDC)3]·xH2O (BIT-72), [Al4(OH)2(OCH3)4(CH3–BDC)3]·xH2O (BIT-73) and {Al4(OH)2(OCH3)4[(CH3)2-BDC]3}·xH2O (BIT-74) have been synthesized by assembling Al3+ ion with terephthalic acid ions decorated with monohydroxyl, monomethyl or dimethyl groups, respectively. All of these three MOFs exhibit high stability in boiling water and acidic conditions. Among them, BIT-72 shows the highest surface area of 1618 m2·g–1 and IAST CO2/N2 selectivity of 48, while BIT-73 and BIT-74 present moderate IAST CO2/N2 selectivity and much lower H2O capacity below P/P0 = 0.3. The high CO2/N2 selectivity together with alleviative H2O sorption at low water relative pressure may provide promising potential in postcombustion CO2 capture.
TL;DR: A metal-organic framework that possesses cascade cysteine oxidase- and peroxidase-mimicking activities and stimulus-responsive fluorescence was designed by coordinating cupric ions with terephthalic acid.
Abstract: A metal-organic framework (CuBDC) that possesses cascade cysteine oxidase- and peroxidase-mimicking activities and stimulus-responsive fluorescence was designed by coordinating cupric ions with terephthalic acid The three-in-one CuBDC provided a new and extremely convenient turn-on fluorescence platform for selective and reliable detection of cysteine
04 May 2018
TL;DR: In this article, a flexible poly[poly(ethylene glycol) methacrylate-co-poly(methylene gels) dimethacrylates] membranes containing metal organic frameworks UiO-66 were constructed from zirconium chloride and 2-aminoterephthalic and terphthalic acid.
Abstract: The key in preparing mixed matrix membranes for the desired gas separation is to rationally select a suitable combination of inorganic fillers and polymers and to develop fabrication techniques enabling formation of a continuous inorganic phase with dual transport pathway. Herein, we report the facile design of flexible poly[poly(ethylene glycol) methacrylate-co-poly(ethylene glycol) dimethacrylate] membranes containing metal organic frameworks UiO-66 prepared from zirconium chloride and 2-aminoterephthalic and terephthalic acid varying in contents, shapes, and sizes. The surface chemistry effects of both polymer matrix and MOFs on permeability and selectivity were investigated. The bare polymer membrane exhibited a permeability for CO2 of around 117 barrer and a selectivity of up to 15. Addition of glycidyl methacrylate in the polymerization mixture led to membranes that were modified with hexamethylenediamine to provide for basicity. However, this modification did not improve performance of the membrane...
TL;DR: The Fe-BDC coating was found to be the most selective and sensitive for the determination of benzene ring contained compounds due to its highly hydrophobic surface and unsaturated metal site.
TL;DR: This is the first attempt to fabricate PICT nanofiber via the electrospinning method and hypothesized that PICT has more trans-configuration than PEICT, resulting in enhancement of its tensile strength, and demonstrated this by Fourier transform infrared spectroscopy.
Abstract: The thermal and mechanical properties of two types of polyester nanofiber, poly (1,4-cyclohexanedimethylene isosorbide terephthalate) (PICT) copolymers and the terpolyester of isosorbide, ethylene glycol, 1,4-cyclohexane dimethanol, and terephthalic acid (PEICT), were investigated. This is the first attempt to fabricate PICT nanofiber via the electrospinning method; comparison with PEICT nanofiber could give greater understanding of eco-friendly nanofibers containing biomass monomers. The nanofibers fabricated from each polymer show similar smooth and thin-and-long morphologies. On the other hand, the polymers exhibited significantly different mechanical and thermal properties; in particular, a higher tensile strength was observed for PICT nanofiber mat than for that of PEICT. We hypothesized that PICT has more trans-configuration than PEICT, resulting in enhancement of its tensile strength, and demonstrated this by Fourier transform infrared spectroscopy. In addition, PICT nanofibers showed clear crystallization behavior upon increased temperature, while PEICT nanofibers showed completely amorphous structure. Both nanofibers have better tensile properties and thermal stability than the typical polyester polymer, implying that they can be utilized in various industrial applications.
TL;DR: Depolymerization of PET was carried out via alkaline hydrolysis by varying reaction time and temperature and maximum yield was obtained at 200 °C with reaction time of 25 minutes and the formed TPA nanospindles were further characterized in detail which exhibited high crystallinity, purity and fascinating thermal and surface properties.
Abstract: Poly(ethylene terephthalate) (PET) is a versatile engineering plastic which exhibits exceptional mechanical and thermal properties. Huge amounts of PET are consumed in various industries such as food packaging industry, textile industry, in the manufacturing of audio, video tapes and X-ray films and so on. But due to its substantial fraction by volume in water bodies and its high persistence to the atmospheric and biological agents, it could be considered as a hazard substance. Thereby chemical recycling of PET serves as a solution to solid waste problem as it transforms PET into its monomers via hydrolysis. Chemical recycling of post consumed waste PET bottles via alkaline hydrolysis is the main aim of this paper. Operating parameters such as reaction time and temperature were optimized for the conversion of PET into nanospindle-shaped terephthalic acid (TPA). Depolymerization of PET was carried out via alkaline hydrolysis by varying reaction time and temperature and maximum yield of 92% was obtained at 200 °C with reaction time of 25 minutes. The formed TPA nanospindles were further characterized in detail which exhibited high crystallinity, purity and fascinating thermal and surface properties.
TL;DR: To comparably analyze the influence of a porous environment on the gas adsorption in MOFs, an analogue MOF has been synthesized by replacing imidazole with triazole motifs, and the activated 1-tz reveals higher adsorptive selectivities for C2H6 andC2H4 over CH4.
Abstract: To comparably analyze the influence of a porous environment on the gas adsorption in MOFs, based on an imidazole-decorated MOF, {[Zn(imtp)]·DMA·1.5H2O}n (1-im, H2imtp = 2-(imidazol-1-yl) terephthalic acid), an analogue MOF, {[Zn(tztp)]·DMA}n (1-tz, H2tztp = 2-(1H-1,2,4-triazol-1-yl) terephthalic acid) has been synthesized by replacing imidazole with triazole motifs. The two MOFs are isostructural frameworks containing 1D channels; however, they possess different porous wall environments. The open nitrogen-decorated channels in 1-tz lead to significantly enhanced C2H6 (76.5 cm3 g–1) and C2H4 (73.1 cm3 g–1) uptakes at 298 K and 1 atm, which are 5 times of the adsorption amounts of C2H6 and C2H4 in 1-im that is the absence of exposed N atoms in the channels. Furthermore, the activated 1-tz also reveals higher adsorption selectivities for C2H6 and C2H4 over CH4. The different sorption properties were further uncovered by theoretical simulations.
TL;DR: In this article, greenhouse gas emissions of 100% bio-derived polyethylene terephthalate were calculated using material balance data from the production process of para-xylene from ethanol under development.
TL;DR: In the industrial PTA-production process, 4-carboxybenzaldehyde (4-CBA) is a detrimental byproduct t... as mentioned in this paper, which is an important product for the polyester and textile industry.
Abstract: Purified terephthalic acid (PTA) is an important product for the polyester and textile industry. In the industrial PTA-production process, 4-carboxybenzaldehyde (4-CBA) is a detrimental byproduct t...
TL;DR: In this paper, a new strategy for the synthesis of 2,5-FDCA from furan and acetic anhydride under mild condition was reported, and the purity of the resulted 2, 5-FD CA was above 99.9%.
Abstract: 2,5-Furandicarboxylic acid (2,5-FDCA) has been regarded as the ideal bio-based alternative to terephthalic acid (TPA). In recent years, great efforts have been made to synthesize 2,5-FDCA through the following methods: (1) oxidation of 5-hydroxymethylfurfural (HMF) in the presence of complex biocatalyst or metallic catalyst; (2) conversion of 2-furoic acid via the well-known Henkel Reaction. Herein, a new strategy for the synthesis of 2,5-FDCA from furan and acetic anhydride under mild condition is reported. The purity of the resulted 2,5-FDCA was above 99.9%. Acetic acid and iodoform generated in the reaction were recyclable and no other harmful by-products were detected. The thus-obtained 2,5-FDCA was applied for the preparation of poly(ethylene furandicarboxylate) (PEF) of high quality in terms of high molecular weight and good appearance.
TL;DR: In this paper, the possibility of recycling polyvinyl chloride (PVC)-coated poly(ethylene terephthalate) (PET) woven fibers through alkaline hydrolysis of PET was investigated.
Abstract: Polyvinyl chloride (PVC)-coated poly(ethylene terephthalate) (PET) woven fibers are one of the hardest-to-recycle polymeric materials. Herein we investigate the possibility of recycling both PVC and PET through alkaline hydrolysis of PET. The coated woven fabrics were treated with NaOH, hydrolyzing the PET fibers into water-soluble sodium terephthalate, while the PVC could be removed by filtration. The PET fibers were completely hydrolyzed between 120 and 180 °C in the presence of 1 M NaOH solution, quantitatively yielding terephthalic acid. A minimum PVC dechlorination rate of 1% was simultaneously achieved at 120 °C. Furthermore, no alkaline hydrolysis of the plasticizer contained in the PVC, di(2-ethylhexyl)phthalate, was observed. Thus, the possibility of simultaneously recycling PET and PVC from PVC-coated woven fabrics was demonstrated. Kinetic analyses of PET hydrolysis and PVC dechlorination revealed that the simultaneously occurring reaction processes did not affect the progress of each other. Thus, the absence of interactions between PET, PVC, or their degradation products enables the design of a simplified recycling process without considering the interactions between the materials derived from coated woven fabrics.
TL;DR: In this paper, the synthesis of transition metal Zn/Ni nitrates and terephthalic acid (BDC) as a precursor dissolved in dimethylformamide (DMF) by solvothermal technique is reported.