Degradation Of Polyethylene Glycol Research Articles

Hydrogen-bonding catalysis of the degradation of polyethylene glycol to 1,4-dioxane over OH-functionalized ionic liquid.

Novel hydrogen-bonding-catalyzed upcycling of polyethylene glycol (PEG) waste to 1,4-dioxane over OH-functionalized ionic liquids (ILs) under mild (≥80 °C), solvent- and metal-free conditions was developed through a theoretical computation-assisted design. Notably, 1,4-dioxane was spontaneously separated due to its immiscibility with ILs.

Intensification of solventless production of hydrophobically-modified ethoxylated urethanes (HEURs) by microwave heating

Hydrophobically modified ethoxylated urethanes (HEURs) are among the most widely studied class of waterborne polyurethanes. HEURs are amphiphilic polymers that are usually composed of a polyethylene glycol (PEG) backbone, typically end-capped with aliphatic alkyl chains. HEUR synthesis in the industry is a slow and energy-intensive step-growth polymerization process, due to heat and mass transfer limitations inherent in such highly viscous systems. We investigate for the first time the effect of microwave heating on both the solvent-free HEUR synthesis step and the initial pretreatment step of the reagents prior to the HEUR synthesis. We show that microwaves can drastically reduce the overall processing time, and thereby reduce total energy consumption by: A) faster melting of solid PEG and B) faster completion of the polymerization reaction, when operating with a novel rapidly rising transient temperature profile that cannot be reproduced by conventional heating. However, it was found that PEG pretreatment/dehydration by microwaves leads to faster degradation of PEG, compared to dehydration by conventional heating at the same bulk temperature, and should therefore be avoided.

Microfluidically-Assisted Isolation and Characterization of Achromobacter spanius from Soils for Microbial Degradation of Synthetic Polymers and Organic Solvents

A micro segmented-flow approach was utilized for the isolation soil bacteria that can degrade synthetic polymers as polyethylene glycols (PEG) and polyacrylamide (PAM). We had been able to obtain many strains; among them, five Achromobacter spanius strains from soil samples of specific sampling sites that were connected with ancient human impacts. In addition to the characterization of community responses and isolating single strains, this microfluidic approach allowed for investigation of the susceptibility of Achromobacter spanius strains against three synthetic polymers, including PEG, PAM, and Polyvinylpyrrolidone (PVP) and two organic solvents known as 1,4-dioxane and diglyme. The small stepwise variation of effector concentrations in 500 nL droplets provides a detailed reflection of the concentration-dependent response of bacterial growth and endogenous autofluorescence activity. As a result, all five strains can use PEG600 as carbon source. Furthermore, all strains showed similar dose-response characteristics in 1,4-dioxane and diglyme. However, significantly different PAM- and PVP-tolerances were found for these strains. Samples from the surface soil of prehistorical rampart areas supplied a strain capable of degradation of PEG, PVP, and PAM. This study demonstrates on the one hand, the potential of microsegment flow for miniaturized dose-response screening studies and its ability to detect novel strains, and on the other hand, two of five isolated Achromobacter spanius strains may be useful in providing optimal growth conditions in bioremediation and biodegradation processes.

Efficient and rapid electrocatalytic degradation of polyethylene glycol by ammonium jarosite

Polyethylene glycol (PEG) in an aqueous environment is a potential problem for water pollution treatment because of its high thermal stability, difficult hydrolysis, and high biocompatibility. This study achieved the efficient and rapid degradation of PEG with a high polymerization degree of PEG (Mn = 20,000 g/mol) in simulated wastewater by a heterogeneous electro-Fenton process using ammonium jarosite as a catalyst. The results showed that the COD removal rate of simulated wastewater and the removal rate of PEG reached 85.85% and 92.29% within 60 min, respectively, and the number average molecular weight (Mn) of PEG was reduced by 79.18% at 180 min under the conditions of 80 mg/L PEG, pH = 3, current density of 5 mA/cm2, ammonium jarosite dosing amount of 0.8 g/L and aeration rate of 1 L/min. The catalytic mechanism of ammonium jarosite was proved that highly oxidative hydroxyl radicals (·OH) in the heterogeneous electro-Fenton process were the most critical active species, which can efficiently and rapidly oxidize PEG molecules. The oxygen atom in the ether bond of PEG molecules has lone pairs of electrons, which interact with the hydroxyl groups on the surface of ammonium jarosite to weaken the ether bonds in the PEG molecules. Then the ether bond is easily to be broken under the attack of the hydroxyl radical. The breakage of the polymer chains during PEG degradation leads to a continuous decrease in the average relative molecular mass of PEG, accompanied by the formation of aldehyde and carboxylic acid intermediates, which are eventually oxidized to form CO2 and H2O as the degradation time increases.

Aerobic biological degradation of organic matter and fracturing fluid additives in high salinity hydraulic fracturing wastewaters

Reuse of hydraulic fracturing wastewaters depends on effective tailored treatment to prepare the water for the intended end use. Aerobic biological treatment of hydraulic fracturing produced water was examined to degrade dissolved organic carbon (DOC) and polyethylene glycols (PEGs). Biological treatment experiments of three produced water samples with DOC concentrations ranging from 22 to 420 mg/L and total dissolved solids (TDS) levels ranging from 26 to 157 g/L were conducted in 48–240 h batches. Samples were not pretreated to remove suspended solids and were inoculated with activated sludge and acclimated over several weeks. Results show that between 50% and 80% of DOC was removed in 12–24 h but a sizeable portion, on a mass basis, remained in the samples with higher DOC concentrations. PEGs were also shown to readily biodegrade into singly- and doubly-carboxylated metabolites, but were not shown to degrade past that point, leading to accumulation of PEG-dicarboxylates (PEG-diCs) in the batch reactors. Possible explanations include residence times that were too long, resulting in starved microbial populations (and thus, a stopping of PEG degradation) or the presence of other ethoxylated additives that degraded into PEGs and PEG-diCs and fed this accumulation. This work demonstrates that a well-acclimated microbial culture is capable of degrading a large portion of DOC in hydraulic fracturing wastewaters across a wide spectrum of TDS concentrations, indicating that biological treatment is a viable option for enabling reuse of produced water.

Decomposition of polyethylene glycol (PEG) at Cu cathode and insoluble anode during Cu electrodeposition

The mechanisms of cathodic and anodic decomposition of polyethylene glycol (PEG), a suppressor in the Cu electrodeposition process, were examined via both cyclic voltammetry stripping (CVS) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) analysis under open-circuit, unpowered closed-circuit, and electrolysis conditions. Under the open-circuit conditions, PEG decomposition occurred only at the cathode (Cu electrode), owing to the effect of the Cu+ ions. Under the unpowered closed-circuit conditions, PEG degraded at both electrodes (Cu and Ir/IrOx on Ti/TiOx) through the galvanic proportionation reaction, owing to which Cu+ was also formed at the anode. Under the electrolysis conditions, PEG also was degraded at both electrodes, but a difference in the average PEG molecular weights (MWPEG) between the two electrodes was observed after 48 h. The PEG breakdown at the cathode appeared to be related to the Cu+ ions, while that at the anode was caused by the •OH radicals formed by water splitting. Remarkably, the PEG decomposition rate under electrolytic conditions was reduced compared with that obtained under the closed-circuit conditions, indicating a lesser extent of radical formation. Therefore, it is concluded that PEG degradation did not proceed through a direct electrochemical reaction, but rather through a radical-induced chemical reaction.

Understanding and Kinetic Modeling of Complex Degradation Pathways in the Solid Dosage Form: The Case of Saxagliptin.

Drug substance degradation kinetics in solid dosage forms is rarely mechanistically modeled due to several potential micro-environmental and manufacturing related effects that need to be integrated into rate laws. The aim of our work was to construct a model capable of predicting individual degradation product concentrations, taking into account also formulation composition parameters. A comprehensive study was done on active film-coated tablets, manufactured by layering of the drug substance, a primary amine compound saxagliptin, onto inert tablet cores. Formulation variables like polyethylene glycol (PEG) 6000 amount and film-coat polymer composition are incorporated into the model, and are connected to saxagliptin degradation, via formation of reactive impurities. Derived reaction equations are based on mechanisms supported by ab initio calculations of individual reaction activation energies. Alongside temperature, relative humidity, and reactant concentration, the drug substance impurity profile is dependent on micro-environmental pH, altered by formation of acidic PEG degradation products. A consequence of pH lowering, due to formation of formic acid, is lower formation of main saxagliptin degradation product epi-cyclic amidine, a better resistance of formulation to high relative humidity conditions, and satisfactory tablet appearance. Discovered insights enhance the understanding of degradational behavior of similarly composed solid dosage forms on overall drug product quality and may be adopted by pharmaceutical scientists for the design of a stable formulation.

Degradation of polyethylene glycols and polypropylene glycols in microcosms simulating a spill of produced water in shallow groundwater.

Polyethylene glycols (PEGs) and polypropylene glycols (PPGs) are frequently used in hydraulic fracturing fluids and have been detected in water returning to the surface from hydraulically fractured oil and gas wells in multiple basins. We identified degradation pathways and kinetics for PEGs and PPGs under conditions simulating a spill of produced water to shallow groundwater. Sediment-groundwater microcosm experiments were conducted using four produced water samples from two Denver-Julesburg Basin wells at early and late production. High-resolution mass spectrometry was used to identify the formation of mono- and di-carboxylated PEGs and mono-carboxylated PPGs, which are products of PEG and PPG biodegradation, respectively. Under oxic conditions, first-order half-lives were more rapid for PEGs (<0.4-1.1 d) compared to PPGs (2.5-14 d). PEG and PPG degradation corresponded to increased relative abundance of primary alcohol dehydrogenase genes predicted from metagenome analysis of the 16S rRNA gene. Further degradation was not observed under anoxic conditions. Our results provide insight into the differences between the degradation rates and pathways of PEGs and PPGs, which may be utilized to better characterize shallow groundwater contamination following a release of produced water.

Acidogenic Fermentation and Anaerobic Co-digestion of Mechanically Sorted OFMSW and Polyethylene Glycol

This study is focused on the anaerobic biological treatment of a polyethylene glycol (PEG)-rich industrial wastewater and mechanically sorted organic fraction of municipal solid wastes, called residual organic matter (ROM), in order to assess the effects of mixing these substrates to produce volatile fatty acids (VFA) through anaerobic co-fermentation or biogas through anaerobic co-digestion. As a consequence of the anaerobic co-digestion of PEG and ROM (PEG representing a 3.5% v/v), the specific methane production (SMP) reached 0.44 Nm3 CH4 kg−1 volatile solids (VS) in front of 0.30 Nm3 CH4 kg−1 VS of the anaerobic digestion (AD) control reactor, with just a 35% higher organic loading rate (OLR) on VS basis. The fast degradation of PEG implied that effluent quality was nearly the same of AD process, showing high stability with neither increase of VS nor significant variations in nutrients. Acidogenic fermentation was carried out in batch tests for several mixtures of PEG industrial wastewater and ROM, where the percentages of PEG-rich wastewater on VS basis were 0, 12.5, 25, 37.5 and 50%. The best results of VFA increase per unit of VS of co-substrate fed was obtained for the mixture with 12.5% of PEG wastewater at 5 days retention time. The same mixture was fed in an anaerobic fermenter under mesophilic conditions treating ROM at an HRT of 3.5 days and without modifying the OLR (VS basis). As a consequence of this co-fermentation, the production of VFA was increased by 14% (12.1 g VFA L−1) when compared with the values obtained in mono-fermentation. Moreover, the percentages of acetic acid + propionic acid (66.5%) was in the range than that obtained with mono-fermentation of ROM (64.6%).

Synthesis, thermal behavior and physicochemical characterization of ZrO2/PEG inorganic/organic hybrid materials via sol–gel technique

Six zirconia–polyethylene glycol (ZrO2/PEG) inorganic/organic hybrid materials were synthesized by the sol–gel technique with different amount of polyethylene glycol (PEG) (corresponding to 6, 12, 24, 50, 60 and 70 mass%). Scanning electron microscopy and Fourier transform infrared spectroscopic (FT-IR) techniques were used in a recent study to characterize the materials with PEG content up to 50 mass%, while in the present one this characterization was extended to the more promising materials with higher PEG content (60 and 70 mass%). All the six materials confirmed their nanocomposite hybrid nature and the formation of hydrogen bonds between the inorganic zirconia matrix and the water-soluble organic component, which involve the Zr–OH groups and both the terminal OH groups and oxygen atoms in the ethereal units of the polymer chains. Moreover, the occurrence of interactions between PEG and acetylacetone, an inhibitor used during the sol–gel synthesis, was observed in the samples with high polymer content. The thermal behavior of all six hybrid materials was studied for the first time by thermogravimetry and differential thermal analysis from room temperature to 1023 K, aiming at identifying all physical and chemical processes occurring in these interesting materials, with particular reference to the decomposition of PEG to establish their thermal stabilities and the most suitable temperature condition for a further thermal treatment. The results revealed that PEG degradation occurs in the range temperature 473–873 K, and the degradation temperature decreases with increasing the PEG content. A probable explanation for PEG-rich materials is due to free PEG (not involved in the formation of H bonds) not affected by the stabilizing effect of the linkage with the inorganic matrix that causes a shift of degradation temperature toward lower values.

Effect of temperature on the synthesis of silver nanoparticles with polyethylene glycol: new insights into the reduction mechanism

Polyethylene glycol (PEG) molecules act as a reducing and stabilizing agent in the formation of silver nanoparticles. PEG undergoes thermal oxidative degradation at temperatures over 70 °C in the presence of oxygen. Here, we studied how the temperature and an oxidizing atmosphere could affect the synthesis of silver nanoparticles with PEG. We tested different AgNO3 concentrations for nanoparticles syntheses using PEG of low molecular weight, at 60 and 100 °C. At the higher temperature, the reducing action of PEG increased and the effect of PEG/Ag+ ratio on nanoparticles aggregation changed. These results suggest that different synthesis mechanisms operate at 60 and 100 °C. Thus, at 60 °C the reduction of silver ions can occur through the oxidation of the hydroxyl groups of PEG, as has been previously reported. We propose that the thermal oxidative degradation of PEG at 100 °C increases the number of both, functional groups and molecules that can reduce silver ions and stabilize silver nanoparticles. This degradation process could explain the enhancement of PEG reducing action observed by other authors when they increase the reaction temperature or use a PEG of higher molecular weight

Detecting Sonolysis of Polyethylene Glycol Upon Functionalizing Carbon Nanotubes.

Polyethylene glycol (PEG) and related polymers are often used in the solubilization and noncovalent functionalization of carbon nanomaterials by sonication. For example, carbon nanotubes are frequently sonicated with PEG-containing surfactants of the Pluronic® series or phospholipid-PEG polymers to noncovalently functionalize the nanotubes. However, PEG is very sensitive to degradation upon sonication and the degradation products can be toxic to mammalian cells and to organisms such as zebrafish embryos. It is therefore useful to have a simple and inexpensive method to determine the extent of potential PEG sonolysis, as described in this chapter. Intact PEG polymers and degraded fragments are resolved on sodium dodecyl sulfate polyacrylamide gels by electrophoresis and visualized by staining with barium iodine (BaI2). Digitized images of gels are acquired using a flatbed photo scanner and the intensities of BaI2-stained PEG bands are quantified using ImageJ software. Degradation of PEG polymers after sonication is readily detected by the reduction of band intensities in gels compared to those of non-sonicated, intact PEG polymers. In addition, the approach can be used to rapidly screen various sonication conditions to identify those that might minimize PEG degradation to acceptable levels.

Complete Genome Sequence of Sphingopyxis macrogoltabida Type Strain NBRC 15033, Originally Isolated as a Polyethylene Glycol Degrader

Sphingopyxis macrogoltabida strain 203, the type strain of the species, grew on polyethylene glycol (PEG) and has been deposited to the stock culture at the Biological Resource Center, National Institute of Technology and Evaluation (NITE), under the number NBRC 15033. Here, we report the complete genome sequence of strain NBRC 15033. Unfortunately, genes for PEG degradation were missing.

The “New Polyethylene Glycol Dilemma”: Polyethylene Glycol Impurities and Their Paradox Role in mAb Crystallization

Polyethylene glycols (PEG) represent the most successful and frequently applied class of excipients used for protein crystallization. PEG auto-oxidation and formation of impurities such as peroxides and formaldehydes that foster protein drug degradation is known. However, their effect on mAb crystallization has not been studied in detail before. During the present study, a model IgG1 antibody (mAb1) was crystallized in PEG solutions. Aggregate formation was observed during crystallization and storage that was ascribed to PEG degradation products. Reduction of peroxide and formaldehyde levels prior to crystallization by vacuum and freeze-drying was investigated for its effect on protein degradation. Vacuum drying was superior in removal of peroxides but inferior in reducing formaldehyde residues. Consequently, double purification allowed extensive removal of both impurities. Applying of purified PEG led to 50% lower aggregate fractions. Surprisingly, PEG double purification or addition of methionine prior to crystallization prevented crystal formation. With increased PEG concentration or spiking with peroxides and formaldehydes, crystal formation could be recovered again. With these results, we demonstrate that minimum amounts of oxidizing impurities and thus in consequence chemically altered proteins are vital to initiate mAb1 crystallization. The present study calls PEG as good precipitant for therapeutic biopharmaceuticals into question.

Rapid detection of polyethylene glycol sonolysis upon functionalization of carbon nanomaterials.

Polyethylene glycol (PEG) and related polymers are often used in the functionalization of carbon nanomaterials in procedures that involve sonication. However, PEG is very sensitive to sonolytic degradation and PEG degradation products can be toxic to mammalian cells. Thus, it is imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results. Described here is a simple and inexpensive polyacrylamide gel electrophoresis method to detect the sonolytic degradation of PEG. The method was used to monitor the integrity of PEG phospholipid constructs and branched chain PEGs after different sonication times. This approach not only helps detect degraded PEG, but should also facilitate rapid screening of sonication parameters to find optimal conditions that minimize PEG damage.

2P4-12 Effect of alcohols on the ultrasonic degradation of polyethylene glycol

2P4-12 Effect of alcohols on the ultrasonic degradation of polyethylene glycol

Computer-based first-principles kinetic Monte Carlo simulation of polyethylene glycol degradation in aqueous phase UV/H2O2 advanced oxidation process.

We have developed a computer-based first-principles kinetic Monte Carlo (CF-KMC) model to predict degradation mechanisms and fates of intermediates and byproducts produced from the degradation of polyethylene glycol (PEG) in the presence of hydrogen peroxide (UV/H2O2). The CF-KMC model is composed of a reaction pathway generator, a reaction rate constant estimator, and a KMC solver. The KMC solver is able to solve the predicted pathways successfully without solving ordinary differential equations. The predicted time-dependent profiles of averaged molecular weight, and polydispersitivity index (i.e., the ratio of the weight-averaged molecular weight to the number-averaged molecular weight) for the PEG degradation were validated with experimental observations. These predictions are consistent with the experimental data. The model provided detailed and quantitative insights into the time evolutions of molecular weight distribution and concentration profiles of low molecular weight products and functional groups. Our approach may be useful to predict the fates of degradation products for a wide range of complicated organic contaminants.

Ammonium Perchlorate, Friend or Foe?

In part 1 of this paper, it was demonstrated that a nitroglycerine and polyethylene glycol based propellant containing ammonium perchlorate degraded at a slower rate at temperatures of 80 °C or less compared with the other two energetic materials studied which did not have this oxidizer present. It was suggested that ammonium perchlorate might act as an oxygen inhibitor reducing the oxidation rate of the polyethylene glycol binder which decreases the rate of propellant decomposition. In part 2, the specific interaction between ammonium perchlorate, nitroglycerine and polyethylene glycol is reported. It has been shown that at temperatures lower than 90 °C, if there is any uncured and unstabilised PEG present, nitroglycerine rapidly degrades in the presence of ammonium perchlorate but this is prevented if stabiliser is added. In addition, ammonium perchlorate initially appears to hinder acid hydrolysis of nitroglycerine which also slows down the degradation of polyethylene glycol based propellants. However, in the long term at low temperatures, or short term at higher temperatures, AP accelerates the decomposition of NG.

Ammonium Perchlorate, Friend or Foe? Part 1: The Influence of this Oxidizer on the Aging Behavior of Propellant Compositions

AbstractPropellants containing nitroglycerine and ammonium perchlorate have been reported to have comparatively shorter shelf lives than analogous energetic materials without this oxidizer. However, investigation into the aging behavior of three compositions containing polyethylene glycol and nitroglycerine revealed that the propellant which included ammonium perchlorate degraded at a slower rate compared with the other materials. It was suggested that ammonium perchlorate might act as an oxygen inhibitor reducing the oxidation rate of the polyethylene glycol binder so decreasing the rate of the propellant decomposition. In addition, at temperatures of 80 °C or lower, ammonium perchlorate initially appears to hinder acid hydrolysis of nitroglycerine which also slows down the degradation of polyethylene glycol based propellant.

高速液体クロマトグラフィ法を用いた硫酸銅めっきの添加剤劣化挙動に関する評価

This study examined the influence of degradation of additive agents upon copper sulfate plating, i.e. polyethylene glycol (PEG) as a depressant, Janes green B (JGB) as a leveler, and bis(3-sulfopropyl) disulfide disodium salt (SPS) as a brightener. Trace analysis was conducted in a copper sulfate bath using high performance liquid chromatography (HPLC), which clarified the respective quantitative limits for measurement of PEG, JGB, and SPS as 10 mg/L, 0.01 mg/L, and 0.15 mg/L. The PEG molecule size and the SPS concentration decreased during electroplating. The value of throwing power was particularly lowered by the PEG degradation. Hydrogenation into N,N-dimethyl-p-phenylenediamine and methylene violet decomposed the JGB, thereby lowering the value of throwing power.