Glycol Ester Research Articles

The effects of N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol on the flame retardancy and physical–mechanical properties of rigid polyurethane foams

Flame-retardant rigid polyurethane foams incorporating N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol have been prepared. After adding N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol, the density and compressive strength of the polyurethane foams were seen to decrease. The flame retardancy of the polyurethane foams has been characterized by limiting oxygen index, upper limit–94, and cone calorimeter tests. The polyurethane foam with 2.27 wt% N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol gave a highest limiting oxygen index of 33.4%, and the peak heat release rate of polyurethane foam reduced to 19.5 kW/m2 from 47.6 kW/m2 of PU-0 without N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol. Upper limit–94 revealed N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol did not change the burning rating, and all polyurethane foams had passed V-0 rating. The thermal stability of polyurethane foams has been investigated by thermogravimetric analyzer. N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly increased the initial decomposition temperature of polyurethane foams and their residues. In addition, the morphology of residual char from the flame-retarded polyurethane foams after cone calorimeter tests has also been characterized by digital photographs. The results indicated that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly enhanced the strength and compatibility of the char layer formed by the polyurethane foams. These results indicate that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol can improve both the quality and quantity of the char, which has a significant effect on the flame-retardant properties of the foam.

Effect of carrier agents on the physical properties and morphology of spray-dried Monascus pigment powder

Spray drying is an economic technique used in preservation and production of Monascus pigment powder. This study was performed to encapsulate the Monascus pigment with maltodextrin using spray drying technique with three types of carrier agents: propylene glycol, mannitol and polyglycerol ester at different concentrations (0.5%, 1% and 1.5%). Analyses of particle size, the spattering behavior, microstructure, color value, and thermal profile were performed on the obtained powder. The addition of propanediol, mannitol and polyglycerol ester in combination with maltodextrin led to an increase of 17.5%, 45.8%, and 23.5% in the volume mean diameter of Monascus pigment powder, respectively. The decrease of spattering of Monascus pigment with maltodextrin was clearly evident in the case of formulations containing 1.5% polyglycerol ester. Scanning electronic microscopy analyses showed that Monascus pigment particle treated with maltodextrin exhibited microstructures that were smooth and dented, while the particles treated with carriers exhibited rough, irregular surface and adherence of smaller particles on their surfaces. UV–visible spectroscopy proved that the addition of carriers did not influence the molecular structure of Monascus pigment compared to the powder without carrier treatment. Differential scanning calorimeter analysis revealed that mannitol enhanced water vaporization during spray drying process as lower enthalpy change was observed in thermogram. The addition of an appropriate carrier (0.5%, 1.5% propanediol or 1% mannitol) improved the color values of Monascus pigment.

Synthesis, Physicochemical Properties, and Thermo-Oxidative Stability of Diesters of 5,7-Dimethyl-1,3-Adamantanediol and 5,7-Dimethyl-1,3-bis(Hydroxymethyl)adamantane

A series of diesters on the basis of 5,7-dimethyl-1,3-adamantanediol and 5,7-dimethyl-1,3- bis(hydroxymethyl)adamantane and C3–C10 aliphatic acids have been synthesized and their physicochemical and thermo-oxidative properties have been studied. The properties of the esters obtained have been compared to those of trimethylolpropane and neopentyl glycol esters.

Nonionic polyol esters as thinner and lubricity enhancer for synthetic-based drilling fluids

This study evaluates the performance of polyol esters as thinners and lubricity enhancers in invert emulsion synthetic-based drilling mud (SBM). Three types of polyol esters, namely pentaerythritol ester (PEE), trimethylolpropane ester (TMPE), and neopentyl glycol ester (NPGE), were prepared at various concentrations of 1, 2, and 3% (v/v) in SBM. The results showed that polyol esters reduced the rheological properties of the drilling mud, such as yield point and gel strength, after the hot rolling test at 135 °C. The rheology data was fitted to the Herschel-Bulkley model to describe the shear thinning behaviour of drilling mud. The model parameters showed that the polyol ester resulted in lower yield stress of SBM, which indicated lower forces are needed to initiate a fluid to move. Their relative effectiveness as a lubricity enhancer was evaluated by measuring the coefficient of friction (COF), wear scar diameter, and scar topography. It was found that polyol esters reduced the COF of SBM by 22% at a concentration of 1% (v/v). PEE provided the best friction reduction and anti-wear performance due to a higher number of the ester group and molecular weight, in comparison with NPGE and TMPE. The lubricity improvement for SBM is recently required by off-shore regulations.

Mechanical and fracture properties of hyperbranched polymer covalent functionalized multiwalled carbon nanotube-reinforced epoxy composites

Using a covalent functionalization strategy, hyperbranched poly (trimellitic anhydride-diethylene glycol) ester epoxy resin (HTDE) was grafted on multiwalled carbon nanotubes (MWCNTs). Then the HTDE grafted MWCNTs (HTDE-g-MWCNTs) were used as toughener to prepare epoxy composites (HTDE-g-MWCNT/EP). The results show that the HTDE-g-MWCNTs are homogeneously dispersed in the epoxy matrix and the tensile strength and fracture toughness of HTDE-g-MWCNT/EP composites are enhanced. The property improvements are due to the enhanced interfacial shear stress and relieved internal residual stress. The main toughening mechanisms are pull-out, breakage of HTDE-g-MWCNTs, and their bridging effect to crack, and shear failure of epoxy matrix around HTDE-g-MWCNTs.

Electrostatically Driven Guest Binding in a Self-Assembled Porous Network at the Liquid/Solid Interface.

We present here the construction of a self-assembled two-dimensional (2D) porous monolayer bearing a highly polar 2D space to study guest co-adsorption through electrostatic interactions at the liquid/solid interface. For this purpose, a dehydrobenzo[12]annulene (DBA) derivative, DBA-TeEG, having tetraethylene glycol (TeEG) groups at the end of the three alternating alkoxy chains connected by p-phenylene linkers was synthesized. As a reference host molecule, DBA-C10, having nonpolar C10 alkyl chains at three alternating terminals, was employed. As guest molecules, hexagonal phenylene-ethynylene macrocycles (PEMs) attached by triethylene glycol (TEG) ester and hexyl ester groups, PEM-TEG and PEM-C6, respectively, at each vertex of the macrocyclic periphery were used. Scanning tunneling microscopy observations at the 1,2,4-trichlorobenzene/highly oriented pyrolytic graphite interface revealed that PEM-TEG was immobilized in the pores formed by DBA-TeEG at higher probability because of electrostatic interactions such as dipole-dipole and hydrogen bonding interactions between oligoether units of the host and guest, in comparison to PEM-C6 with nonpolar groups. These observations are discussed based on molecular mechanics simulations to investigate the role of the polar functional groups. When a nonpolar host matrix formed by DBA-C10 was used, however, only phase separation and preferential adsorption were observed; virtually no host-guest complexation was discernible. This is ascribed to the strong affinity between the guest molecules which form by themselves densely packed van der Waals networks on the surface.

Synthesis and Study of Ethylene Glycol Esters of Synthetic Petroleum Acids as Diesel Fuel Additives

Esters were synthesized using synthetic petroleum acids and ethylene glycol. The esterification was carried out in various types of reactors in the presence of commercial Zeokar-600 catalyst. Physicochemical properties of the synthesized esters and of 5 and 10% compounds of these esters with the diesel fraction were determined. The esters obtained can be used as additives to diesel fuels to improve their performance properties.

Liquid chromatography–tandem mass spectrometry detection of diclofenac and related compounds in water samples

A frequently studied environmental contaminant is the active substance diclofenac, which is removed insufficiently in sewage treatment plants. Since its inclusion in the watch list of the EU Water Framework Directive, the concentrations in surface waters will be determined throughout Europe. For this, still, more precise analytical methods are needed. As a reference, HPLC-MS is frequently employed. One of the major metabolites is 4'-hydroxydiclofenac (4'-OH-DCF). Also, diclofenac lactam is important for assessing degradation and transformation. Aceclofenac (ACF), the glycolic acid ester of diclofenac is used as a drug, too, and could potentially be cleaved to yield diclofenac again. In various sewage treatment plant influent samples, diclofenac, 4'-OH-DCF, DCF lactam and ACF could be determined with detection limits of 3 μg/L, 0.2 μg/L, 0.17 μg/L and 10 ng/L, respectively.

Potential antihyperlipidemic polyketones from endophytic Diaporthe sp. JC-J7 in Dendrobium nobile.

Eleven new polyketones named diaporthsins A–K (1–11) were isolated from the fermentation of Diaporthe sp. JC-J7. The chemical structures of compounds (1–11) were elucidated by spectroscopic methods including HRESIMS, 2DNMR, NMR and chemical methods. Compound 11 features an unusual acyclic polyketone–phenolic polyketone hybrid structure that integrates the characteristics of different fungal metabolites (cytosporone and multiplolide). Compound 3 was the only C12-polyketone obtained in this research. These new polyketones showed inhibitory activity on triglycerides (TG) in steatosis hepatocyte L-02 cells. Among them, compound 5 and (4E)-6,7,9-trihydroxydec-4-enoic acid displayed inhibitory activities on TG in steatotic L-02 cells with inhibition ratios of 26% and 21% at concentration of 5 μg mL−1; also, inhibition ratios of 8-O-acetylmultiplolide A and phomopsisporone A at concentration of 5 μg mL−1 were calculated to be about 24% and 16%, respectively, which were equivalent to the antihyperlipidemic activity of lovastatin. The preliminary structure–activity relationship indicated that acetyl at C-8 can increase the antihyperlipidemic activity of multiplolide A and the glycol ester and hydroxyl at C-6 can also increase the corresponding activity of diaporthsin B.

Synthesis and Evaluation of Biocide and Cetane Number Improver Additives for Biodiesel from Chemical Changes in Triacylglycerides

Biodiesel demand is increasing all over the world and the inhibition of microbial growth during the storage of this biofuel is extremely important. There are few studies involving the evaluation of biocides specifically for biodiesel. In the present work, we synthesized and evaluated a set of biocide candidates from chemical transformations in triacylglycerides. Samples of pure biodiesel with the products were evaluated against microorganisms which have been isolated from biodiesel/diesel blends (fungi A. niger, A. fumigatus, C. albicans and S. cerevisiae; and bacteria B. subtilis and Acinetobacter sp.). None of the products inhibited the growth of bacteria. Four nitrated derivatives presented fungicidal activity. The nitrated derivatives were also evaluated as cetane number improvers for B7 biodiesel/diesel blend. The nitrates of soybean methoxylated ethylene glycol esters increased the cetane number by more than three points. Despite showing modest biocide activity, the results can guide the planning of new products from triacylglycerides.

Properties of Polyurethane Coatings Based on Linseed Oil Phosphate Ester Polyol

Linseed oil was epoxidized using hydrogen peroxide (H2O2), acetic acid (AcOH) and ion exchange resin Amberlite IR-120 as a catalyst. Epoxidized oil was separately dissolved in isopropyl alcohol (IPA) or diethylene glycol butyl ether (DGBE) and phosphorylated with different amounts of phosphoric (H3PO4) acid (1%, 2%, 3% and 5%). The formation of phosphate polyesters was confirmed by Fourier-transform infrared (FTIR) and 31P nuclear magnetic resonance (NMR) spectra. Based on the synthesized polyols, polyurethane (PU) coatings were prepared. PU coating based on linseed oil diethylene glycol ester polyol was used as the reference. For the characterization of coatings, mechanical tests and thermogravimetric analysis (TGA) were used. The flammability parameters of wood samples with PU coatings at a heat flux of 35 kW/m2 were determined. It was found that PU coatings based on IPA polyols had higher mechanical characteristics, char residue upon thermal decomposition and flame retardancy.

Hexagonal Molecular Tiling by Hexagonal Macrocycles at the Liquid/Solid Interface: Structural Effects on Packing Geometry.

We present here hexagonal tiling using hexagonal phenylene-ethynylene and phenylene-butadiynylene macrocycles attached by alkyl ester groups, PEM-C6 and PBM-C8, respectively, or triethylene glycol ester groups, PEM-TEG and PBM-TEG, respectively, at each vertex of the macrocyclic periphery at the liquid/solid interface. In this study, we focused on the effects of macrocyclic core size and the chemical properties of side chains attached to macrocyclic cores as well as solute concentrations on the hexagonal geometry of self-assembled monolayers. STM observations at the 1,2,4-trichrolobenzene/graphite interface revealed that PEM-C6 formed a honeycomb structure by van der Waals interactions between the interdigitated alkyl chains. However, upon increasing solute concentration, it changed to more dense hexagonal structure (tentatively called loose hexagonal structure I). In contrast, PBM-C8 formed loose hexagonal structure II of a slightly different packing mode at low concentration, while at high concentration it formed a high-density hexagonal structure in which alkyl chains are not adsorbed on the surface (dense hexagonal structure). In the dense hexagonal structure, macrocyclic cores are linked by hydrogen bonds between the ester carbonyl oxygen and the aromatic hydrogen atoms of the neighboring macrocycles. The packing geometries of loose hexagonal structures of PEM-C6 and PBM-C8 are different due to the different distance between the attachment of the alkyl ester groups which are located in confined space. On the other hand, PEM-TEG and PBM-TEG formed dense hexagonal structures, similar to PBM-C8 at high concentration, with their TEG units not adsorbed on the surface.

Evaluating electrolyte additives for lithium-ion cells: A new Figure of Merit approach

Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li1.03Ni0.5Mn0.3Co0.3O2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethyl phosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2 M LiPF6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using these two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. Our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.

Tris(trimethylsilyl)silylboronate Esters: Novel Bulky, Air- and Moisture-Stable Silylboronate Ester Reagents for Boryl Substitution and Silaboration Reactions

New, bulky tris(trimethylsilyl)silylboronate pinacol and hexylene glycol esters ((TMS)3Si–B(pin) and (TMS)3Si–B(hg)) were prepared in 46 and 61% yields, respectively, by the reaction of tris(trimethylsilyl)silylpotassium with the corresponding boron electrophiles. Notably, these silylboronate esters exhibited high stability to air and silica gel and were applied to the transition-metal-free boryl substitution of aryl halides, providing the desired borylated products in high yields with excellent B:Si ratios (up to 96% yield, B/Si = 99/1). These new silylboronate esters were also applied to a sequential borylation/cross-coupling process with various aryl halides, as well as the base-mediated silaboration of styrene.

Tailoring strategies of polyalkylene glycol ester for varied lube applications

Three biodegradable/ecofriendly polyalkylene glycol esters 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 [polyglycol containing 1:4 mol fraction of propylene oxide (PO) and tetrahydrofuran (THF)] esterified with propionic acid (C3 fatty acid), hexanoic acid (C6 fatty acid) and octanoic acid (C8 fatty acid) were synthesized via two-step reaction mechanism. Initially, propylene oxide and tetrahydrofuran were polymerized in 1,2 dichloroethane to obtain a polymer 1,4-PTH (polyglycol containing 1:4 mol fraction of PO and THF) with molecular weight ( $$\overline{{M_{n}}}$$ ) 1070.7. Finally, esterification of 1,4-PTH was done with varied fatty acids, i.e., C3, C6 and C8 fatty acid catalyzed by p-toluenesulfonic acid and toluene as solvent to obtain final products 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 having the molecular weights ( $$\overline{{M_{n}}}$$ ) 1154.78, ( $$\overline{{M_{n}}}$$ ) 1192.86 and ( $$\overline{{M_{n}}}$$ ) 1220.91, respectively. The molecular structure and crystallinity of the synthesized poly(propyleneoxide-co-tetrahydrofuran) ester was studied by FT-IR, X-ray diffraction and DSC. The physicochemical properties like; pour point (ASTM 97), kinematic viscosity (ASTM 445), viscosity index (ASTM 2270), refractive index, density, thermal stability, autoignition temperature (IS 7895), corrosion stability and oxidation stability (IP 48) were determined. The extreme pressure (IP 239) and antiwear properties (ASTM D 4172) were also evaluated in terms of weld load and average wear scar diameter, respectively. Hence all the properties so determined were compared with the specifications of lube oils and it was revealed that these poly(propyleneoxide-co-tetrahydrofuran) esters, i.e., 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 had suitable physical and tribological properties to be used as base stock for compressor lubricant, metal working fluid and fire-resistant hydraulic fluid.

Synthesis and properties of polyester-based polymeric surfactants from diterpenic rosin

A series of polymeric surfactants, poly acrylic acid rosin polyethylene glycol esters (P-AAR-PEG), have been synthesized from natural diterpenic rosin. Their structures were characterized by Fourier Transform Infrared Spectrometer (FTIR) and their molecular weights were characterized by Gel Permeation Chromatography (GPC). Their critical micelle concentration (CMC), surface tension (γCMC), foaming property (FP), and hydrophile-lipophile balance (HLB) value were evaluated. Their thermal properties were measured by Thermal Gravimetric Analyzer (TGA) and fluid behaviors were studied by Rotational Rheometer. The influence of concentration on the properties of oil-in-water emulsions was examined and contrasted the stability of emulsion by the mean droplet size between day1 and day7. The weight-average molecular weight of P-AAR-PEG ranged from 1770 to 5071. CMC values of P-AAR-PEG were ranged from 0.33 to 0.87g/L and the corresponding γCMC values were ranged from 37.8 to 39.1mN/m respectively. Their CMC and γCMC values decreased and then increased with the increment of molecular weight of hydrophile group. Rheological measurements indicated that the P-AAR-PEG solutions changed from pseudoplastic property to Newtonian with increasing shear rate. P-AAR-PEG1000 had good emulsion ability to turpentine in water. When the concentration of P-AAR-PEG1000 was 8wt%, the emulsion remained stable for more than 7days.

Modeling and parameter estimation of step‐growth polymerization of poly(ethylene‐2,5‐furandicarboxylate)

The production of polymers from renewable materials has arisen increasing interest because of the environmental impacts caused by conventional processes. In this context, the present manuscript investigates the step‐growth polymerization of poly(ethylene 2,5‐furandicarboxylate), PEF, a furanic polyester with structural similarity to poly(ethylene terephthalate), PET, using ethylene glycol (EG), and 2,5‐furandicarboxylic acid (FDCA) as monomers. The polymerization is performed in two steps: direct esterification of EG and FDCA under continuous nitrogen flow, followed by the transesterification of produced diesters and oligomers under reduced pressure. In order to do that, experiments were performed at distinct reaction temperatures and using different nitrogen flow rates. Based on the obtained experimental data, a mathematical model was built and model parameters were estimated to allow for appropriate description of available data. The obtained results indicate that the rates of polymerization are highly limited by mass transfer and removal of reaction byproducts. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

Synthesis and Pharmacological Properties of Linear Poly(Ethylene Glycol)s Conjugated to Interferon α-2b by Azo Coupling

A method for the preparation of pharmacologically active conjugates of interferon α-2b with poly(ethylene glycol)s that absorbed in the visible spectral range was proposed. New covalent conjugates of linear poly(ethylene glycol)s with interferon α-2b were prepared via diazotization of 4-aminobenzoic acid poly(ethylene glycol) esters followed by azo coupling of the obtained diazonium salts with histidine imidazoles and tyrosine phenols of the protein amino-acid chain. The synthesized conjugates retained a high degree of interferon α-2b antiviral activity in vitro and had longer blood circulation times than a foreign analog and very low acute toxicity and immunogenicity.

Development of a Biodegradable/Ecofriendly Turbine Lubricant from a Novel Polyalkylene Glycol Ester

A biodegradable/ecofriendly polyalkylene glycol ester 1,2-PTHC6 (polyglycol containing 1:2 mol fraction of propylene oxide (PO) and tetrahydrofuran (THF)) esterified with n-hexanoic acid (C6 fatty acid) was synthesized following the two step reaction. At first, propylene oxide and tetrahydrofuran were polymerized in 1, 2-dichloroethane to obtain a polymer 1,2-PTH (polyglycol containing 1:2 mol fraction of PO and THF) with molecular weight ( $$\overline{{{\text{M}}_{{\text{n}}} }}$$ ) 838.6. In the second step, esterification of 1,2-PTH was done with C6 fatty acid catalyzed by p-toluenesulfonic acid and toluene as solvent to obtain final product 1,2-PTHC6 having the molecular weight ( $$\overline{{{\text{M}}_{{\text{n}}} }}$$ ) 982.7. The crystallinity and molecular structure of the synthesized poly(propyleneoxide-co-tetrahydrofuran) ester was studied by FT-IR, X-ray diffraction and DSC. The physicochemical properties like; pour point (ASTM 97), kinematic viscosity (ASTM 445), viscosity index (ASTM 2270), refractive index, density, thermal stability, autoignition temperature (IS 7895), corrosion stability and oxidation stability (IP 48) were evaluated. The extreme pressure (IP 239) and antiwear properties (ASTM D 4172) were also evaluated in terms of weld load and average wear scar diameter respectively. All the properties so determined were compared with the specifications of lube oils and it was revealed that this poly(propyleneoxide-co-tetrahydrofuran) ester i.e. 1,2-PTHC6 had suitable physical and tribological properties to be used as base stock for turbine lubricant.

Combined effect of linseed oil and gum rosin as natural additives for PVC

Polyvinyl chloride (PVC) was plasticized with epoxidized linseed oil (ELO) an further added with triethylene glycol ester of gum rosin (TEGR) as natural viscosity increasing agent. Although, the addition of both additives resulted in some colour changes, since TEGR induced red tone and ELO produced an amber tonality, all formulations showed high brightness and transparency. FTIR was used to study the changes in the plastisol chemical structures due to the addition of both natural additives. The microstructure of plastisols, studied by SEM observations, further confirmed that ELO and TEGR presented good compatibility with PVC resin, particularly when a mixture of ELO and TEGR was used. Therefore, changing the proportion of both natural additives allows designing tunable plastisols employing renewable materials.