Pentaerythritol Ester Research Articles

Vegetable Oil Based Compressor Oil-optimising of Tribological Characteristics

ABSTRACT This study explored the use of vegetable oil-based polyolester of rapeseed oil as a potential biolubricant for reciprocating air compressor. Rapeseed oil-based pentaerythritol ester (PE) was formulated via ultrasound-assisted transesterification process. Response surface methodology (RSM) based D-optimal design of experiments was used to analyse the tribological parameters, such as disc rotational speed, load and compressor oils on various tribological behaviours, namely, coefficient of friction (COF) and specific wear rate (SWR) using a pin-on-disc tribometer. The least specific wear rate of 1.85 × 10−5 mm3/Nmand COF of 0.0393 was recorded at optimal conditions. The surface morphology analysis of the tested pin using SEM/EDX and tribo-film formation analysis of disc surface using XPS technique disclosed that blended compressor oil (PE75), i.e., 75% by volume of PE and 25% by volume of synthetic compressor oil (SAE30) has numerous capabilities as environmental friendly compressor oil.

Occurrence and in vitro toxicity of organic compounds in urban background PM2.5

This study describes the chemical composition and in vitro toxicity of the organic fraction of fine particulate matter (PM2.5) at an urban background site, which receives emissions either from Frankfurt international airport or the city centre, respectively. We analysed the chemical composition of filter extracts (PM2.5) using ultrahigh-performance liquid chromatography coupled to a high-resolution mass spectrometer, followed by a non-target analysis. In parallel, we applied the bulk of the filter extracts to a Microtox and acetylcholinesterase-inhibition assay for in vitro toxicity testing. We find that both the chemical composition and toxicity depend on the prevailing wind directions, and the airport operating condition, respectively. The occurrence of the airport marker compounds tricresyl phosphate and pentaerythritol esters depends on the time of the day, reflecting the night flight ban as well as an airport strike event during November 2019. We compared the organic aerosol composition and toxicity from the airport wind-sector against the city centre wind-sector. We find that urban background aerosol shows a higher baseline toxicity and acetylcholinesterase inhibition compared to rural PM2.5 that is advected over the airport. Our results indicate that the concentration and individual composition of PM2.5 influence the toxicity. Suspected drivers of the acetylcholinesterase inhibition are i.e. organophosphorus esters like triphenyl phosphate and cresyldiphenyl phosphate, and the non-ionic surfactant 4-tert-octylphenol ethoxylate. However, further research is necessary to unambiguously identify harmful organic air pollutants and their sources and quantify concentration levels at which adverse effects in humans and the environment can occur.

Pequi Oil Esters as an Alternative to Environmentally Friendly Lubricant for Industrial Purposes

This study reports the synthesis of bio-based lubricants using pequi oil (PO) as a raw material, along with its chemical, thermal, and rheological characterization, as well as its cytotoxic behavior and the kinetic study of the reaction involved in the production of biolubricants. Free fatty acid pequi oil (PFFA) was esterified using 2-ethyl-1-hexanol (P2EHE), pentaerythritol (PPEE), and p-TSA as catalysts. The 1H NMR spectra confirmed the replacement of hydroxyl groups of both alcohols by PFFA. PPEE showed better thermal stability (Tonset 274.50 °C). Besides, at 50% of thermal weight loss, the PPEE showed a higher decomposition temperature (437.9 °C) than PO (366.6 °C). The melting points determined by DSC indicate that P2EHE exhibits better performance at low temperatures (p.p. −22.86 °C) than PPEE (p.p. −33.28 and 8.02 °C) due to the presence of some crystals of saturated fatty acids in the pentaerythritol ester. The esters showed Newtonian behavior in a wide range of shears; however, they showed pseudoplastic behavior at temperatures above 60 °C. The viscous nature of bio-based lubricants was confirmed (G″ > G′) even with increasing temperature. The kinetic study provided the value of the activation energy to P2EHE and PPEE, similar to that reported in the literature for other types of biolubricants. The toxicity analysis of bio-based lubricants on adult zebrafish showed no lethality after 96 h. These results suggest that pequi oil is a potential raw material to produce lubricants that are less harmful to the environment.

Steric hindrance effect on miscibility and properties of palm oil derived pentaerythritol ester lubricants

The miscibility and solubility between refrigerant and lubricant is a prerequisite in any refrigeration system. Polyol is known to have good miscibility with refrigerant and can be synthesized from methyl ester of vegetable oils via transesterification reaction. Pentaerythritol (PE) ester is the best biolubricant in hydrofluorocarbons (HFCs) refrigerant system due to its high viscosity. PE ester was analyzed for its physicochemical properties and was compared with commercial refrigeration polyol ester (POE) RL 68H. The kinematic viscosity and density of PE ester were comparable with commercial POE. The pour point was obtained at −24 °C which is slightly higher than commercial POE. Nevertheless, the PE ester was not completely miscible in refrigerant, HFC R134a. The miscibility with refrigerant decreases as the number of ester functional group increases and the number of fatty acids carbon chain increases because of the neopentyl structure of esters hindered the ester functional group to interact with polar group of HFC refrigerant. An appropriate surfactant is needed to improve the miscibility and solubility of PE ester with HFC refrigerant.

Синтез сложных эфиров оксипропилированного 2,2,5,5-тетраметилолциклопентанола и исследование их в качестве перспективных смазочных материалов

At present, with the development of modern technology, the requirements for lubricating oils, especially their viscosity-temperature, thermo-oxidative and lubricating characteristics, are becoming more stringent. In this aspect, the synthesis and study of esters of oxypropylated 2,2,5,5-tetramethylolcyclopentanol (TMCP) with cyclic fragments, active centers, multipolar ester groups is promising, have a certain scientific and practical significance.The esters were synthesized by the esterification reaction of oxypropylated TMCP with aliphatic monocarboxylic acids C4-C8, and their physicochemical, viscosity-temperature, thermal-oxidative and lubricating properties were studied. After determining the viscosity-temperature properties, it was established that they have a low pour point (minus 38-minus 430C), an average viscosity at 1000C (ν100 = 23.50-40.22 mm2/s), a high viscosity index (133-150 units) and flash point (305-3800C). When determining the thermo-oxidative stability of esters, it was found that they have low acid numbers after oxidation (2.51-3.28 mg KOH/g), corrosion of electrodes AK-4 (0.06-0.16 mg/cm2), ШХ -15 (0.08-0.11 mg/cm2) and the precipitate is insoluble in isooctane is low (0.120-0.248% of the mass), the volatility is 0.30-0.50% of the mass. The lubricating properties of esters were also determined: critical load Рк,Н = 750-900, spot wear diameter Di,mm at Р = 196Н = 0.50-0.65. Oxypropylated esters in comparison with reference esters - TMCP ester with caproic acid and pentaerythritol ester (PET) and mixture of fatty acids (MFA) fr. C5-C6 surpass them in almost all parameters, are higher molecular weight and promising, and this makes it possible to create on their basis high-temperature lubricating oils special purpose, components or additives to other lubricating oils.

Partially Dehydrated Castor Oil-Based Isoalkyl and Polyol Esters as Potential Base Stocks for Industrial Applications

Partially dehydrated castor oil (PDCO) which is of less use in the paint and furniture coating formulations has been modified to develop biolubricant base stocks. PDCO (44.1%, non-conjugated linoleic acid; 32%, conjugated linoleic acid (18:2) isomers and 15.3% ricinoleic acid) obtained from a local industry was hydrolyzed under alkaline conditions. The fatty acids obtained (PDCFAs) in 98% yields were reacted with polyols namely 2-ethyl hexanol, neopentyl glycol, trimethylol propyl, pentaerythritol to obtain respective isoalkyl erters and esters of polyol with >95% yield. The base stocks exhibited very high viscosity indices (187.288 to 187.687), excellent pour point (-25 to -40 ºC) and high flash points (212 to 317 ºC) required for a variety of industrial applications namely metal working, hydraulic, forging, cutting fluid, gear oil applications. The tribological properties of PDCO, exhibited very low WSD (0.72-0.79 mm) and WSVs (0.82-0.83 mm3) with high load carrying capacities (180-220 kg) indicating low friction and less energy losses between the sliding surfaces. This was also accompanied by very high thermo-oxidation stabilities [Oxidation stability (230-242 ºC); Onset temperature (300-381 ºC)] of the base stacks due to branching. Overall all the PDCO isoalkyl and polyol esters exhibited excellent properties suitable for a wide range of industrial applications on par with mineral oil based lubricants.

Kinetic Studies of Esterification of Rosin and Pentaerythritol

Esterification of rosin with pentaerythritol produces rosin pentaerythritol ester (RPE) which is widely used in paint, coating, and pressure-sensitive and hot-melt adhesive industries. Although RPE has excellent valuable applications and has been industrially produced, studies on the reaction kinetics have not been widely reported in the present literature. This work proposed a kinetic study of RPE synthesis by including a series of consecutive reactions forming mono-, di-, tri-, and tetra-ester with decarboxylation of rosin as a side reaction in the kinetics model. For esterification, the reaction rates were determined by the second-order kinetic model. The first-order kinetic order was proposed for decarboxylation. Kinetic experiments were performed at a temperature range of 260 °C to 290 °C. The initial molar ratio of pentaerythritol to rosin (in the mole of OH/COOH) used was between 0.8 and 1.2. A small amount of samples were withdrawn in certain time interval. The sample was analyzed to evaluate their acid and saponification number. Afterward, those experimental data were used to simulate and validate the proposed kinetic model. In general, the proposed model could capture the experimental data well. The resulting activation energies ranged from 65.81 to 129.13 kJ mol−1 for esterification and 233.00 kJ mol−1 for decarboxylation. This model also offers a new insight that correlates well with tetra-ester formation and the softening point.

Synthetic oils based on pentaerythritol esters. Vapor pressure and enthalpy of vaporization

Pentaerythritol esters (2,2-bis(hydroxymethyl)propane-1,3-diol) esters and other esters are widely used as components of machine oils, motor oils, hydraulic fluids and plasticizers. The advantages of such esters are high thermal oxidative and hydrolytic stability, and good tribological properties. In this work, the equilibrium vapor pressures and enthalpies of vaporization (298.15 K) of nine esters of pentaerythritol combined with C2–C7 acids of various structures were determined by the vapor transpiration method in the temperature range of 358–433 K. The vaporization enthalpies of the pentaerythritol esters with homologous acids are found to correlate with their retention indicies and the number of carbon atoms in the linear acid residue. Enthalpies of vaporization of the compounds studied have also been calculated by the QSPR-method. These results have been verified by experimental values.

Synthesis of bismaleate pentaerythritol ester and its application as PVC auxiliary heat stabilizer

AbstractDiethylene glycol and maleic anhydride are used as raw materials to prepare bismaleic acid dibasic acid without catalyst. This intermediate product reacts with pentaerythritol (PER) to obtain bismaleate pentaerythritol (MDPP) as an auxiliary heat stabilizer. The structure of the product was verified by Fourier infrared test and hydrogen nuclear magnetic spectrum analysis. The ether bond, ester group, carbon–carbon double bond, polyol, and other characteristic structures contained in the molecule can improve thermal stability. Therefore, it can be used as an auxiliary heat stabilizer for PVC and used in combination with the main heat stabilizer. In order to verify the thermal stability performance and further analyze the thermal stability mechanism, testing methods such as thermal aging, Congo red, thermal weight loss, and electrical conductivity were adopted. The results show that when MDPP is added together with calcium/zinc stearate, the thermal stability of PVC is the best. The initial whiteness can reach 40 min, and the static stabilization time is 65 min, which is 15 min higher than the PVC sample with PER and calcium/zinc stearate. It can be seen that MDPP has greatly improved performance compared with the commercial auxiliary heat stabilizer PER.

Synthesis, Identification, and Isolation of Esters of Pentaerythritol and Linear С4–С7 Carboxylic Acids

Synthesis, Identification, and Isolation of Esters of Pentaerythritol and Linear С4–С7 Carboxylic Acids

Films Based on Thermoplastic Starch Blended with Pine Resin Derivatives for Food Packaging.

Completely biobased and biodegradable thermoplastic starch (TPS) based materials with a tunable performance were prepared for food packaging applications. Five blends were prepared by blending TPS with 10 wt%. of different pine resins derivatives: gum rosin (GR), disproportionated gum rosin (RD), maleic anhydride-modified gum rosin (CM), pentaerythritol ester of gum rosin (LF), and glycerol ester of gum rosin (UG). The materials were characterized in terms of thermo-mechanical behavior, surface wettability, color performance, water absorption, X-ray diffraction pattern, and disintegration under composting conditions. It was determined that pine resin derivatives increase the hydrophobicity of TPS and also increase the elastic component of TPS which stiffen the TPS structure. The water uptake study revealed that GR and LF were able to decrease the water absorption of TPS, while the rest of the resins kept the water uptake ability. X-ray diffraction analyses revealed that GR, CM, and RD restrain the aging of TPS after 24 months of aging. Finally, all TPS-resin blends were disintegrated under composting conditions during the thermophilic incubation period (90 days). Because of the TPS-resin blend’s performance, the prepared materials are suitable for biodegradable rigid food packaging applications.

Films Based on Mater-Bi® Compatibilized with Pine Resin Derivatives: Optical, Barrier, and Disintegration Properties

Mater-Bi® NF866 (MB) was blended with gum rosin and two pentaerythritol esters of gum rosin (labeled as LF and UT), as additives, to produce biobased and compostable films for food packaging or agricultural mulch films. The films were prepared by blending MB with 5, 10, and 15 wt.% of each additive. The obtained films were characterized by optical, colorimetric, wettability, and oxygen barrier properties. Moreover, the additives and the MB-based films were disintegrated under composting conditions and the effect of each additive on the biodegradation rate was studied. All films were homogeneous and optically transparent. The color of the films tended to yellow tones due to the addition of pine resin derivatives. All the formulated films presented a complete UV-transmittance blocking effect in the UVA and UVB region, and those with 5 wt.% of pine resin derivatives increased the MB hydrophobicity. Low amounts of resins tend to maintain the oxygen transmission rate (OTR) values of the neat MB, due to its good solubilizing and compatibilizing effects. The disintegration under composting conditions test revealed that gum rosin completely disintegrates in about 90 days, while UT degrades 80% and LF degrades 5%, over 180 days of incubation. As expected, the same tendency was obtained for the disintegration of the studied films, although Mater-Bi® reach 28% of disintegrability over the 180 days of the composting test.

Rheological investigation of synthetic-based drilling fluid containing non-ionic surfactant pentaerythritol ester using full factorial design

Non-ionic surfactant pentaerythritol ester (PE ester) can be used as a lubricant and chemical thinner in flocculated synthetic-based mud (SBM). However, its adsorption on surfaces and at oil-water interfaces may interfere with anionic secondary emulsifier and organoclay additives in the mud. The interactions between these additives may significantly affect the viscosity of SBM emulsions. Therefore, in this study, we systematically developed SBM formulations containing a non-ionic surfactant PE ester and evaluated the interactions between the surfactant, secondary emulsifier, and organoclay that influence the rheology of SBM using a full factorial design. Three rheological properties were chosen as responses: plastic viscosity (PV) and yield point (YP), and YP/PV ratio. Factorial analysis of the interaction between the secondary emulsifier and PE ester showed that the interactions caused significant effects on PV, YP, and YP/PV ratio. These multiple responses were optimized using the desirability function, and the optimum formulation was at concentrations of 1.0 lb/bbl, 6.2 lb/bbl, and 1.0% for secondary emulsifier, organoclay, and PE ester, respectively. A quantitative relationship between the various factors and responses was established, allowing a prediction of desirable rheological properties for drilling operations.

Influence of Biodegradable Refrigeration Oil in Household Refrigerator Compressor: An Experimental and Tribological Investigation

The present investigation is aimed at finding the suitability of using vegetable oil-based polyol ester as biodegradable refrigeration oil. Rapeseed oil-based pentaerythritol ester was synthesized via successive trans-esterification route. The formulation was blended with synthetic refrigeration oil (POE68) in the fractions of 25%, 50% and 75% by volume. The tribological investigation involving various refrigeration oils was done using the four-ball tribometer. This study further quantifies the influence of biodegradable refrigeration oils on the performance of domestic refrigerator compressor using vapour compression refrigeration test setup. The process of tribological analysis brought to light the comparable anti-friction and excellent wear reduction behaviour with the blended refrigeration oil sample (BIO50—i.e., 50% by vol. of pentaerythritol ester of rapeseed oil and 50% by vol. of POE68). It was noticed that the BIO50 had considerable rise in coefficient of performance (COP) of about 41.7% and prime impact on the performance of refrigeration compressor. The outcome of the experimental study is supportive in finding vegetable oil-based refrigeration oil to substitute partially the synthetic grade for the domestic refrigerator compressor.

Identification and source attribution of organic compounds in ultrafine particles near Frankfurt International Airport

Abstract. Analysing the composition of ambient ultrafine particles (UFPs) is a challenging task due to the low mass and chemical complexity of small particles, yet it is a prerequisite for the identification of particle sources and the assessment of potential health risks. Here, we show the molecular characterization of UFPs, based on cascade impactor (Nano-MOUDI) samples that were collected at an air quality monitoring station near one of Europe's largest airports, in Frankfurt, Germany. At this station, particle-size-distribution measurements show an enhanced number concentration of particles smaller than 50 nm during airport operating hours. We sampled the lower UFP fraction (0.010–0.018, 0.018–0.032, 0.032–0.056 µm) when the air masses arrived from the airport. We developed an optimized filter extraction procedure using ultra-high-performance liquid chromatography (UHPLC) for compound separation and a heated electrospray ionization (HESI) source with an Orbitrap high-resolution mass spectrometer (HRMS) as a detector for organic compounds. A non-target screening detected ∼200 organic compounds in the UFP fraction with sample-to-blank ratios larger than 5. We identified the largest signals as homologous series of pentaerythritol esters (PEEs) and trimethylolpropane esters (TMPEs), which are base stocks of aircraft lubrication oils. We unambiguously attribute the majority of detected compounds to jet engine lubrication oils by matching retention times, high-resolution and accurate mass measurements, and comparing tandem mass spectrometry (MS2) fragmentation patterns between both ambient samples and commercially available jet oils. For each UFP stage, we created molecular fingerprints to visualize the complex chemical composition of the organic fraction and their average carbon oxidation state. These graphs underline the presence of the homologous series of PEEs and TMPEs and the appearance of jet oil additives (e.g. tricresyl phosphate, TCP). Targeted screening of TCP confirmed the absence of the harmful tri-ortho isomer, while we identified a thermal transformation product of TMPE-based lubrication oil (trimethylolpropane phosphate, TMP-P). Even though a quantitative determination of the identified compounds is limited, the presented method enables the qualitative detection of molecular markers for jet engine lubricants in UFPs and thus strongly improves the source apportionment of UFPs near airports.

Improvement of PBAT Processability and Mechanical Performance by Blending with Pine Resin Derivatives for Injection Moulding Rigid Packaging with Enhanced Hydrophobicity.

Polybutylene adipate-co-terephthalate (PBAT) is a biodegradable polymer with good features for packaging applications. However, the mechanical performance and high prices of PBAT limit its current usage at the commercial level. To improve the properties and reduce the cost of PBAT, pine resin derivatives, gum rosin (GR) and pentaerythritol ester of GR (UT), were proposed as sustainable additives. For this purpose, PBAT was blended with 5, 10, and 15 wt.% of additives by melt-extrusion followed by injection moulding. The overall performance of the formulations was assessed by tensile test, microstructural, thermal, and dynamic mechanical thermal analysis. The results showed that although good miscibility of both resins with PBAT matrix was achieved, GR in 10 wt.% showed better interfacial adhesion with the PBAT matrix than UT. The thermal characterization suggested that GR and UT reduce PBAT melting enthalpy and enhance its thermal stability, improving PBAT processability. A 10 wt.% of GR significantly increased the tensile properties of PBAT, while a 15 wt.% of UT maintained PBAT tensile performance. The obtained materials showed higher hydrophobicity than neat PBAT. Thus, GR and UT demonstrated that they are advantageous additives for PBAT–resin compounding for rigid food packaging which are easy to process and adequate for industrial scalability. At the same time, they enhance its mechanical and hydrophobic performance.

Thermal Stability Evaluation of Resin Acids and Rosin Modified Resins.

Rosin is a sustainable resource, which is mainly composed of resin acid. Rosin-modified resin is widely used in adhesives, inks, coatings, and other fields, and its stability is very important for the production, storage, and use of products. Thermal stability and reactivity of three resin acids (levopimaric acid, neoabietic acid, and dehydroabietic acid) and four rosin-modified resins were studied using an accelerating rate calorimeter (ARC). They are stable, and exothermic reactions do not occur even when they were heated to 200 °C under a nitrogen atmosphere, but they are unstable under an oxygen atmosphere. The mechanism of the oxidation reaction process was found: first, resin acids absorb oxygen, and then an exothermic oxidation occurs. The initial exothermic temperature (T0) of levopimaric acid, neoabietic acid, and dehydroabietic acid are 354.01, 353.83, and 398.20 K, the initial oxidation kinetics shows a second-order reaction, and the activation energies (Ea) are 42.90, 58.05, and 46.60 kJ/mol, respectively. Peroxide concentration of three resin acids were determined by iodometry. The T0 values of hydrogenated rosin, disproportionated rosin, hydrogenated rosin glyceride, and hydrogenated rosin pentaerythritol ester, the four rosin-modified resin, are 353.71, 348.32, 412.85, and 412.44 K. Levopimaric acid and neoabietic acid have higher oxidative reactivity and easily undergoes an oxidation reaction at lower temperature. Rosin-modified resins are stable and find it difficult to undergo oxidation reactions.

Retention Indices and Sorption Enthalpies of Pentaerythritol and С2–С8 Acid Esters on Nonpolar Stationary Phases

The retention and sorption enthalpy characteristics of 38 pentaerythritol esters of C2–C8 carboxylic acids of different structures were determined by gas-liquid chromatography on a nonpolar phase in the temperature range 433.2–563.2 K. The molecular structure was shown to affect the temperature dependence of the retention indices of the esters. The average change in the sorption enthalpy of pentaerythritol tetraesters per CH2 group is lower in magnitude than the similar contribution for normal alkanes. The excess mixing enthalpy at 298.2 K was evaluated for four fully substituted pentaerythritol esters.

CuO-nano based Biodegradable Refrigeration Oil in R134a Refrigeration Systems for Energy Conservation and Green Environment

The present study experimentally investigated the reliability and performance of a vapour compression refrigeration system with CuO nano based biodegradable refrigeration oil. The pentaerythritol ester biodegradable refrigeration oil (PE) is blended with synthetic refrigeration oil (ISO 68 grade-POE oil) in the fraction of 50% by volume. Nanolubricant was synthesized on the basis of the concept of the nanofliuds, which was prepared by mixing CuO nanoparticles with pentaerythritol ester based biodegradable refrigeration oil blend (PE50). The concentration of nano CuO ranges in the order of 0.1% to 0.3% by weight with particle size of 40 nm to prepare CuO nano biodegradable refrigeration oil. An experimental test rig is designed and fabricated indigenously to carry out the investigations. The results indicated that CuO nano-based biodegradable refrigeration oil works normally and safely in the system. The compressor power consumption was reduced by 5.02% with the use of 0.3% CuO nano biodegradable refrigeration oil. The PE50 with 0.3% CuO nano has a considerable rise in coefficient of performance (COP) of about 45%. Hence CuO nano-based biodegradable refrigeration oil in refrigeration system considerably reduces the energy consumption and increases the COP of the refrigeration system.

Polyolester Based Lubricant from Waste Feedstock for Sustainable Environment: A Tribological Investigation

This study reported the tribological evaluation of polyolester based lubricant synthesised from waste feedstock. The transesterification process was adopted for the formulation of lubricant from waste mango seed kernel oil. The polyols used in this formulation are neopentyl glycol, trimethylolpropane and pentaerythritol. The tribological investigation was conducted using four ball tribometer as per ASTM D4172. The frictional and wear behavior of vegetable oil-based polyolester was analysed in addition to the wear morphology of investigated balls. The results indicated that the average frictional torque and mean wear diameter of pentaerythritol ester of waste mango seed oil was 0.12 Nm and 0.403 mm respectively and also found that the pentaerythritol ester showed improved tribological results as compared with other polyolesters say neopentyl glycol ester and trimethylolpropane ester of waste mango seed oil. The waste mange seed oil is found suitable candidate for the formulation of polyolester based sustainable lubricant.