Acid Dimethyl Ester Research Articles

Structure, thermal and mechanical properties of copoly(ester amide)s based on 2,5\u2010furandicarboxylic acid

In this work, new bio-based copoly(ester amide)s were synthesized by a two-step melt polycondensation process, using 2,5-furanedicarboxylic acid dimethyl ester (DMFDC), 1,3-propanediol (PDO), and 1,3-diaminopropane (DAP), with different DAP content. The chemical structure of the obtained poly(trimethylene 2,5-furandicarboxylate)-co-poly(propylene furanamide) (PTF-co-PPAF) copolymers was confirmed by nuclear magnetic resonance (1H NMR) and Fourier-transform infrared (FTIR) spectroscopy. Gas chromatography/mass spectrometry was used to provide more details of the polycondensation process. Thermal properties of the obtained materials were characterized by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic–mechanical thermal analysis (DMTA). The copolymers were amorphous and their glass transition temperature increased with the increase in the poly(propylene furanamide) (PPAF) content. The synthesized PTF-co-PPAF copolymers exhibited improved thermal and thermo-oxidative stability up to 300 °C. In addition, from the performed mechanical tests, it was found that along with the increase in PPAF content, Young's modulus increased, while at the same time, the value of elongation at break decreased.Graphical

Orientation Analysis of Polymer Chains in Optically Transparent Biopolyimides Having Rigid and Bending Backbones

AbstractOptically transparent and heat‐resistant polymer films are useful in the field of organic glasses usable for electric insulators for panels, windows, optical devices, etc. A series of biopolyimides having non‐π‐conjugated backbones prepared using a renewable diamine, 4,4′‐diaminotruxillic acid dimethyl esters, and various dianhydride monomers were prepared and cast onto substrates to form transparent films with high heat resistances and good electric resistance. The second order orientation coefficients (P200) of the biopolyimide films were evaluated by polarized attenuated total reflection Fourier‐transform infrared spectroscopy, and the P200 values for the C−N stretching vibrations at a wavenumber of 1365 cm−1 displayed a good correlation with that for the aromatic C−C stretching at 1510 cm−1, regardless of the dianhydride structure. The in‐plane/out‐of‐plane birefringence and coefficients of linear thermal expansion exhibited strong correlations with P200 except for those of a few samples. Most of the biopolyimide films exhibited good transparencies with low birefringence and high electric resistance, which are applicable to flexible substrates with a low coefficient of thermal expansion for panel displays.

Direct catalytic conversion of bagasse fibers to furan building blocks in organic and ionic solvents

The applications of lignocellulosic wastes to produce a wide variety of products, including biochemicals, biomaterials, and biofuels, can be an effective solution for utilizing these valuable waste materials. In this study, the production of furan building blocks from bagasse fibers was investigated by treating unbleached fibers with NMMO, [Bmim]Cl, and TMAH at different temperatures using AlCl3 and CrCl2 as the catalysts. The resulted liquors were extracted with CH2Cl2 to obtain furan rich fraction. Analysis of extracted fractions with GC/MS indicates the production of various furanic compounds due to catalytic solvolysis with different solvents at elevated temperatures. 2(3H)-Furanone and 2-methyl-THF were the main products of catalytic treatment of bagasse fibers with NMMO. Treatment by [Bmim]Cl resulted in 2,5-dihydro furanone as the dominant product at elevated temperatures. Furan carboxylic acid methyl ester and 2,5-furan dicarboxylic acid dimethyl ester were the main TMAH reaction products with unbleached fibers. The results indicate that the type of solvent affects the solvolysis rate and dehydration of cellulose to furanic compounds. Moreover, increasing the temperature led to an increase in the formation of the furanic compounds.Graphical abstract

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines.

Two series of functionalized imidazothiazolotriazine derivatives were synthesized via the condensation of imidazo[4,5-e]-1,2,4-triazine-3-thiones with acetylenedicarboxylic acid dimethyl and diethyl esters (DMAD and DEAD) and subsequent base-catalyzed rearrangement of the obtained imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazines into regioisomeric imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine derivatives.

Flame Retardant Modified Bio‐Based Waterborne Polyurethane Dispersions Derived from Castor Oil and Soy Polyol

AbstractAlthough tremendous efforts have been dedicated to developing environmentally friendly bio‐based waterborne polyurethane (WPU) dispersions from vegetable oil, the fabrication of WPU dispersions solely derived from vegetable oil‐based polyol with excellent comprehensive properties is still challenging. In the present work, novel bio‐based WPU dispersions derived from castor oil and soy polyol is successfully modified by phosphorus‐nitrogen chain extender [bis(2‐hydroxyethyl)amino]‐methyl‐phosphonic acid dimethyl ester (BH). The structure and properties of the dispersions and films are characterized systematically by Fourier transform infrared spectroscopy, thermogravimetric analysis , mechanical test, and limiting oxygen index (LOI), etc. The results indicate that bio‐based WPU films display moderate mechanical performance by adjusting BH content, and the WPU film containing 100% BH with 47.8% biobased content has a tensile strength of 8 MPa and the highest Young's modulus of 62.3 MPa. The incorporation of BH can increase the production of char residue. The flame retardancy of WPU films increase gradually with the BH molar content, and the LOI value of the WPU100 with 1.53 wt% phosphorus content can reach as high as 28.1%. This work may provide a new approach to develop high biobased content, eco‐friendly, flame retardant WPU for application in the surface coating industry.

Glutamate is an essential mediator in glutamine-amplified insulin secretion.

Aims/IntroductionGlutamine is the most abundant amino acid in the circulation. In this study, we investigated cell signaling in the amplification of insulin secretion by glutamine.Materials and MethodsClonal pancreatic β‐cells MIN6‐K8, wild‐type B6 mouse islets, glutamate dehydrogenase (GDH) knockout clonal β‐cells (Glud1KOβCL), and glutamate‐oxaloacetate transaminase 1 (GOT1) knockout clonal β‐cells (Got1KOβCL) were studied. Insulin secretion from these cells and islets was examined under various conditions, and intracellular glutamine metabolism was assessed by metabolic flux analysis. Intracellular Ca2+ concentration ([Ca2+]i) was also measured.ResultsGlutamine dose‐dependently amplified insulin secretion in the presence of high glucose in both MIN6‐K8 cells and Glud1KOβCL. Inhibition of glutaminases, the enzymes that convert glutamine to glutamate, dramatically reduced the glutamine‐amplifying effect on insulin secretion. A substantial amount of glutamate was produced from glutamine through direct conversion by glutaminases. Glutamine also increased [Ca2+]i at high glucose, which was abolished by inhibition of glutaminases. Glutamic acid dimethylester (dm‐Glu), a membrane permeable glutamate precursor that is converted to glutamate in cells, increased [Ca2+]i as well as induced insulin secretion at high glucose. These effects of glutamine and dm‐Glu were dependent on calcium influx. Glutamine also induced insulin secretion in clonal β‐cells MIN6‐m14, which otherwise exhibit no insulin secretory response to glucose.ConclusionsGlutamate converted from glutamine is an essential mediator that enhances calcium signaling in the glutamine‐amplifying effect on insulin secretion. Our data also suggest that glutamine exerts a permissive effect on glucose‐induced insulin secretion.

Simultaneously improving the fracture toughness and flame retardancy of soybean oil-based waterborne polyurethane coatings by phosphorus-nitrogen chain extender

Despite tremendous efforts have been dedicated to developing environmentally-friendly waterborne polyurethane (WPU) coatings from renewable biomass resources like soybean (Glycine max (L.) Merrill) oil, the fabrication of WPU coatings with high fracture toughness and flame retardancy is still challenging. In the present work, novel soybean oil-based waterborne polyurethane (SPU) coatings and the resultant films with significantly improved fracture toughness and flame retardancy as well as good deformation recovery were successfully synthesized via a chain extension technique by using [bis(2-hydroxyethyl)amino]-methyl- phosphonic acid dimethyl ester (BH) and 1,4-butane diol (BDO) as chain extenders. The structure and properties of the coatings and films were characterized systematically by FTIR, DMA, TGA, mechanical test and limiting oxygen index (LOI), etc. The results indicated that the mechanical properties of SPU films could be effectively improved by the introduction of BH, and SPU80 with 80 % BH molar ratio in the chain extenders showed remarkable improvements in mechanical properties like tensile strength (∼6.28 fold, 8.8 MPa), elongation at break (∼1.26 fold, 1510.9 %) and fracture toughness (∼4.70 fold, 64.8 MJ/m3) comparing to those of SPU20 with 20 % BH molar ratio. The incorporation of BH could delay the maximum decomposition speed of SPU films and increase char residue production. The flame retardancy of SPU films increased gradually with the BH molar content, and the LOI value of the SPU80 with 0.9 wt% phosphorus content could reach as high as 28.2 %. This work provides a new approach to develop multifunctional SPU coating with a tunable performance by incorporating phosphorus-nitrogen chain extender.

Synthesis, Characterization, and Encapsulation of Novel Plant Growth Regulators (PGRs) in Biopolymer Matrices.

Novel plant growth regulators (PGRs) based on the derivatives of dehydroamino acids 2,3-dehydroaspartic acid dimethyl ester (PGR1), Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid (PGR2) and 1-methyl-3-methylamino-maleimide (PGR3) have been synthesized and their growth-regulating properties investigated. Laboratory testing revealed their plant growth-regulating activity. PGR1 showing the most stimulating activity on all laboratory tested cultures were used in field experiments. Results showed that PGR1 is a highly effective environmentally friendly plant growth regulator with effects on different crops. Biopolymeric microcapsule formulations (chitosan/alginate microcapsule loaded with PGR) suitable for application in agriculture were prepared and characterized. Physicochemical properties and release profiles of PGRs from microcapsule formulations depend on the molecular interactions between microcapsule constituents including mainly electrostatic interactions and hydrogen bonds. The differences in the microcapsule formulations structure did not affect the mechanism of PGRs release which was identified as diffusion through microcapsules. The obtained results opened a perspective for the future use of microcapsule formulations as new promising agroformulations with a sustained and target release for plant growth regulation.

Biodegradation of acetyl cellulose etrols

This work aimed to study the biodegradation dynamics of plasticized cellulose acetate samples (etrols) with different content of plasticizers. Isophthalic acid dimethyl ester and orthophosphoric acid tributyl ester were used as plasticizers. The targets of the study also included assessing the effect of the plasticizers’ content on the degradation rate. The biodegradability of plasticized cellulose acetate samples was assessed by measuring the weight loss after exposure to active soil. For the experiment, an active soil of the following composition was prepared: garden soil - 89 vol. %, distilled water - 10 vol. %, microbiological preparation “Tamir” - 1 vol. %. All etrols samples showed a tendency to decomposition in active soil. The rate of sample degradation varied significantly. The highest degradation rate in active soil was shown by a sample containing 16 wt. % tributyl phosphate and 22 wt. % dimethyl isophthalate, as good as ertols sample containing 8 wt. % tributyl phosphate and 14 wt. % dimethyl isophthalate. The expected decomposition time of these samples in the active soil for 90% is 599 and 732 days, respectively. Changing of dimethyl isophthalate content did not affect the degradation rate. Withal the content of tributyl phosphate in the etrols induced a significant effect on the samples’ weight loss. The consequence of the plasticizers’ content on the weight loss rate for 145 days of exposure in the active soil is described by the equation y=-4.76+1.25·Z 1+1.49·Z2-0.04·Z 1 2-0.086·Z22+0.000141 where Z1 is the content of dimethyl isophthalate, Z2 is the content of tributyl phosphate.

Microwave Assisted Amidation of 5-Aminoisophtalic Acid Dimethyl Ester Catalyzed by Imidazolium Ionic Liquids

Amide functionalities present in living system as peptides and possess various biological role. Many synthetic amides also possess biological activities due to the possibility of interaction with cellular liquids such as those compounds useful as a contrast agent in radiographic method. Synthesis of amides from the carboxylic acid or derivatives normally require heating and catalyst. In this report, an environmentally benign synthesis of amide was carried out utilizing microwave radiation and catalyzed by imidazolium ionic liquids (BMIMCl). Microwave radiation provided efficient heating through activation of chemical bonds instead of conventional conductivity methods hence increasing the rate of reactions. Ionic liquids were suitable material in this synthesis due to non-volatile nature as well as stability under high temperature and microwave heating. Furthermore, ionic liquids are tunable material that can be designed for the specific synthesis and functioned as a catalyst. The optimum condition for coupling of 5-Amino-isophthalic acid dimethyl ester with an amino diol was found at 80 °C, 90 minutes, under radiation of microwave at the power of 300 Watt. The product was obtained at 38.46% yield. Furthermore, the methodology was applied to synthesis radiographic material and was successful to obtain product with 48.78% yield. The products were characterized by NMR spectroscopy.

A novel route for aspartame production by combining enzymatic and chemical reactions for industrial use.

Here, we report a novel industrial aspartame production route, involving the enzymatic production of α-l-aspartyl-l-phenylalanine β-methylester from l-aspartic acid dimethylester and l-phenylalanine by α-amino acid ester acyl transferase. The route also involves the chemical transformation of α-l-aspartyl-l-phenylalanine β-methylester to α-l-aspartyl-l-phenylalanine methylester hydrochloride (aspartame hydrochloride) in an aqueous solution with methanol and HCl, followed by HCl removal to form aspartame.

Preparation and activity of ruthenium catalyst based on β-cyclodextrin for ring-opening metathesis polymerization

Inspired by substrates-recognition of enzymes, we prepared supramolecular catalyst (Ru-βCD Cat) for ring-opening metathesis polymerization (ROMP) by modifying second generation Grubbs catalyst® (M204) with β-cyclodextrin (βCD) derivative (VPhe-βCD). The ROMP activity of Ru-βCD Cat was demonstrated using 7-oxanorbornene-2,3-dicarboxylic acid dimethyl ester (ONorCOOMe). The VPhe-βCD cavity recognized the ONorCOOMe monomer and attached to catalytic metal center of Ru-βCD Cat to grow poly(ONorCOOMe) with higher yield and molecular weight (Mn) in aqueous medium. The yield and Mn were higher than those of poly(ONorCOOMe) obtained by second generation Hoveyda-Grubbs catalyst® (M720). 1-Adamantanol hindered ONorCOOMe from occupying the βCD cavity, acting as a competitive guest molecule. The inhibition caused lower polymer yield and Mn. These results showed that molecular recognition of ONorCOOMe by the cavity of Ru-βCD Cat is important to increase the polymer yield and Mn of poly(ONorCOOMe).

Separation of Fatty Acid Dimethyl Esters on an Ionic Liquid Gas Chromatographic Column.

An ionic liquid (IL) 111 column was compared with other commonly employed stationary phases including polydimethyl siloxane and polyethylene glycol for the separation of fatty acid monomethyl and dimethyl esters. The fatty acid esters employed in this study were derived from metathesis reactions of vegetable oils both with and without olefins. The IL 111 column demonstrated enhanced performance compared with conventional columns for the separation of these esters. These advantages included significantly enhanced retention of dimethyl esters relative to monomethyl esters, excellent cis/trans isomer separation and the ability to analyze higher carbon number dimethyl esters. As a result, these columns are highly suited for the analysis of mixtures of mono- and dimethyl fatty acid esters found in lipid metathesis reaction products or to determine monofunctional impurities in samples of commercial dimethyl esters.

New trivalent phosphorus containing poly(arylene ether)s as alternative reactants for the Mitsunobu reaction

Novel phosphine containing poly(arylene ether)s with trivalent phosphorus are prepared by reaction of bis(4-fluorophenyl) phenylphosphine with 2,2-bis(4-hydroxyphenyl)propane. The reaction conditions are adjusted to avoid partial oxidation of the phosphine derivative during polycondensation. Solution polycondensation results in copolymers with phosphine and phosphorus oxide containing repeating units with high molar contents of phosphine oxide (up to 45 mol% P = O repeating units), while solvent-free melt polycondensation of bis(4-fluorophenyl) phenylphosphine with bis(trimethylsilyl)-2,2-bis(4-oxyphenyl)propane and CsF as catalyst yields 85 mol% phosphine containing repeating units. The weight-averaged molar masses are in the range of 40,000 g/mol.The phosphine containing polymers are used, to illustrate an example, as polymeric reagent in the Mitsunobu reaction for the etherification of 5-hydroxyisophthalic acid dimethylester with henicosaperfluoroicosanol to yield a monomer for semifluorinated polyesters. The Mitsunobu reaction requires triaryl phosphine derivatives as reactants which are oxidized to phosphorus(V) compounds during the course of the reaction. The separation of the oxidized products in the reaction with triphenyl phosphine (TPP) is generally complicated and the application of the novel poly(aryl ether)s results in simplification of the work-up and increase of the yield of the desired product (33% with TPP vs. 55% with the phosphine containing poly(aryl ether) P13). Thus, the applicability of the polymers as polymer-supported phosphine derivatives replacing low molar mass phosphines is demonstrated.

Preparation of flame-retardant/dyed cotton fabrics: flame retardancy, dyeing performance and flame retardant/dyed mechanism

An environmentally friendly phosphorous-nitrogen synergistic flame retardant, 6-monochloro-1,3,5-triazine-4-p-aminobenzenesulfonate-2-methylphosphinic acid dimethyl ester (CTSGP), was synthesized and applied to improve the thermal stability of cotton fabrics. The chemical structure of GTSGP was analyzed by Fourier transform infrared spectroscopy, and the appearance of its group characteristic peaks indicated that the compound was successfully prepared. The flame retardant reacted with the hydroxyl groups of cotton fabrics to constitute covalent bonds that bunch firmly to the surface. The flame retardancy of the treated cotton fabrics was evaluated by the limiting oxygen index (LOI) and vertical flammability test. The results showed that the LOI value of cotton fabrics treated by CTSGP increased from 18.0 to 29.0%, the length of char residue was only 62 mm without after-flame time and after-glow time. The thermogravimetric and cone calorimetry test results showed that the char-forming ability of the treated cotton fabrics was significantly improved and the peak heat release rate decreased from 144.23 to 11.64 kW/m2. Besides, the mixed dyeing behavior of GTSGP and reactive dyes showed that the cotton fabrics can obtain the ideal color and flame retardant performance at the same time. The color fastness to wet rubbing of the flame-retardant/dyed fabrics reaches 4, and the softness is slightly improved compared with untreated cotton fabrics. The non-flammable nitrogen gas and organophosphate carbon layer generated by the treated cotton fabrics during combustion contribute to the flame resistance of fabrics. A reactive phosphor-nitrogen flame retardant (CTSGP) was synthesized and applied to cotton fabrics to obtain excellent flame retardant property.

NOVEL VARIANTS OF THE MULTICOMPONENT REACTION FOR THE SYNTHESIS OF 1,2,4-TRIAZOLO[1,5- а ]PYRIMIDINES AND PYRIDO[3,4- е ][1,2,4]TRIAZOLO[1,5- а ]PYRIMIDINES

A new multicomponent reaction for regioselective synthesis of substituted 1,2,4-triazolo[1,5-a]pyrimidines using aminotriazoles, β-ketoglutaric acid dimethyl ester, and dimethylformamide dimethyl acetal was implemented. The selective reduction of 1,2,4-triazolo[1,5-a]pyrimidines to dihydro derivatives and the use of triazolo pyrimidines as starting compounds in multicomponent synthesis of dihydropyrido[3,4-е][1,2,4]triazolo[1,5-a]pyrimidinecarboxylates was demonstrated.

Critical Electric Field and Activation Energy for Electric Conductivity for Biopolyimide Using 4,4′-Diamino-α-truxillic Acid and 1,2,3,4-Cyclobutanetetracarboxylic Dianhydride

Biopolyimides poly(ATA-CBDA) made from of 4,4′-diamino-α-truxillic acid dimethyl ester (ATA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) were synthesized and its electric volume resistivity measured at various electric voltages at 10–60 °C. The volume resistivity for Kapton and biopolyimide films showed a sudden decrease at a critical electric field of 2.6 × 107 and 1.0 × 107 V/m, respectively. The activation energy at low electric field for Kapton and biopolyimide was 68 and 90 kJ/mol, respectively, meanwhile at high electric field for Kapton and biopolyimide was 45 and 74 kJ/mol, respectively. These results indicate that the carriers for electric conduction for biopolyimide weakly interact with the polymer chain and the biopolyimide contains many conductive carriers than Kapton.

Novel variants of the multicomponent reaction for the synthesis of 1,2,4-triazolo[1,5-а]pyrimidines and pyrido[3,4-е][1,2,4]triazolo[1,5-а]pyrimidines

A new multicomponent reaction for regioselective synthesis of substituted 1,2,4-triazolo[1,5-a]pyrimidines using aminotriazoles, β-ketoglutaric acid dimethyl ester, and dimethylformamide dimethyl acetal was implemented. The selective reduction of 1,2,4-triazolo-[1,5-a]pyrimidines to dihydro derivatives and the use of triazolo pyrimidines as starting compounds in multicomponent synthesis of dihydropyrido[3,4-е][1,2,4]triazolo[1,5-a]pyrimidinecarboxylates was demonstrated.

Heterogeneous Catalytic Conversion of Sugars Into 2,5-Furandicarboxylic Acid.

Achieving the goal of living in a sustainable and greener society, will need the chemical industry to move away from petroleum-based refineries to bio-refineries. This aim can be achieved by using biomass as the feedstock to produce platform chemicals. A platform chemical, 2,5-furandicarboxylic acid (FDCA) has gained much attention in recent years because of its chemical attributes as it can be used to produce green polymers such polyethylene 2,5-furandicarboxylate (PEF) that is an alternative to polyethylene terephthalate (PET) produced from fossil fuel. Typically, 5-(hydroxymethyl)furfural (HMF), an intermediate product of the acid dehydration of sugars, can be used as a precursor for the production of FDCA, and this transformation reaction has been extensively studied using both homogeneous and heterogeneous catalysts in different reaction media such as basic, neutral, and acidic media. In addition to the use of catalysts, conversion of HMF to FDCA occurs in the presence of oxidants such as air, O2, H2O2, and t-BuOOH. Among them, O2 has been the preferred oxidant due to its low cost and availability. However, due to the low stability of HMF and high processing cost to convert HMF to FDCA, researchers are studying the direct conversion of carbohydrates and biomass using both a single- and multi-phase approach for FDCA production. As there are issues arising from FDCA purification, much attention is now being paid to produce FDCA derivatives such as 2, 5-furandicarboxylic acid dimethyl ester (FDCDM) to circumvent these problems. Despite these technical barriers, what is pivotal to achieve in a cost-effective manner high yields of FDCA and derivatives, is the design of highly efficient, stable, and selective multi-functional catalysts. In this review, we summarize in detail the advances in the reaction chemistry, catalysts, and operating conditions for FDCA production from sugars and carbohydrates.

A re-investigation of the mycolic acids of Mycobacterium avium

Mycolic acid methyl esters were extracted from Mycobacterium avium by a mild saponification protocol, designed to preserve labile components. The resulting mixture of α-, keto- and wax ester mycolates was accompanied by some degraded ω-carboxymycolic acid dimethyl esters, whose overall structures were found to support previous studies. Chromatography of the mono-carboxylic mycolates gave an inseparable mixture of keto- and wax ester mycolates and separate α-mycolates. Reduction of the ketomycolate components allowed isolation and characterisation of intact wax ester mycolates for the first time. Minor α- and ω-carboxymycolates were detected in which methyl branches were located on either the proximal or distal sides of trans-alkene groups.