Trimethylolpropane Ester Research Articles

Transesterification of trimethylolpropane and rapeseed oil methyl ester to environmentally acceptable lubricants

AbstractBiodegradable trimethylolpropane [2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol] esters of rapeseed oil fatty acids were synthesized by transesterification with rapeseed oil methyl ester both by enzymatic and chemical means, both in bench and pilot scales. Nearly complete conversions were obtained with both techniques. A reduced pressure of about 2 to 5 kPa, to remove the methanol formed during transesterification, was critical for a high product yield. The quantity of added water was also critical in the biocatalysis. Candida rugosa lipase was used as biocatalyst and an alkaline catalyst in chemical transesterifications. In biocatalysis the maximum total conversion to trimethylolpropane esters of up to 98% was obtained at 42°C, 5.3 kPa, and 15% added water. The maximum conversion of about 70% to the tri‐ester was obtained at the slightly higher temperature of 47°C. The reaction time was longer in the biocatalysis, but considerably higher temperatures were required in chemical synthesis. In the chemical synthesis tri‐ester yields increased when the temperature was first held at 85 to 110°C for 2.5 h and subsequently increased to up to 120°C for 8 h. The trimethylolpropane esters obtained were tested as biodegradable hydraulic fluids and compared to commercially available hydraulic oils. The hydraulic fluids based on trimethylolpropane esters of rapeseed oil had good cold stability, friction and wear characteristics, and resistance against oxidation at elevated temperatures.

Modified TMP esters as multifunctional additives in metalworking fluids

AbstractThis paper looks at newly developed trimethylolpropane (TMP) esters, which have multifunctional properties as additives in aqueous metalworking fluids. Such TMP esters can replace the previous monofunctional esters, which provided only lubrication.New TMP esters are obtained by chemical modification of traditional TMP esters, and provide the functions of lubrication, corrosion protection, and co‐emulsification in one product. The paper looks at the chemistry of these esters, and their properties. Some experimental products are also examined.

Elucidation of the Antiwear Performance of Several Organic Phosphates Used with Different Polyol Ester Base Oils from the Aspect of Interaction between Additive and Base Oil

The antiwear performance of organic phosphates, such as tricresylphosphate (TCP), tributylphosphate (TBP) and diphenylhydrogen-phosphate (DPHP), dissolved in several polyol esters is studied. Several trimethylolpropane esters (TMP) and pentaerythritol esters (PE) having different carbon chains were used as base oils. A four-ball tribometer was used to determine the antiwear performance of oils, using commercially available bearing steel balls as test specimens. Although the wear of steel was drastically reduced with low-concentration solutions of these phosphates, the wear increased with increasing concentration in the higher-concentration region. All of the phosphates showed characteristics of an optimum concentration for minimizing wear. This behavior can be attributed to the effective adsorption/reaction of phosphates in the low concentration region and the reaction forming excess inorganic phosphates on the surface that causes corrosive-like wear in the high-concentration region. Different polyol esters showed different optimum concentrations of the additive. The order of optimum concentration among the polyol esters was different with different phosphates. Although the wear rate absolute values at the optimum concentration did not show clear correlation, it is shown that the effect of the concentration of additives on the antiwear performance can be explained by the interaction between additives and base oils using the solubility parameter. Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

Properties of Polyol Esters–-Lubrication of an Aluminum Silicon Alloy

The chemical and physical properties of lubricants significantly affect their performance in industrial applications where aluminum is used as a sliding material. The inertness of aluminum contributes to its poor wear resistance. The wear characteristics of a series of polyol esters were evaluated in terms of their chemical structure for the lubrication of an aluminum-silicon (Al-Si) alloy using a pin-on-disc-type wear tester. The molecular structure and the number of acid groups of the polyol esters strongly affected their ability to lubricate the Al-Si alloy. The wear and scuffing performances of the polyol esters with the longer linear-chain acids were better than those of the esters with shorter branched acid chains. For esters of the same number of carbon atoms, neopentylglycol-type esters had higher scuffing loads than trimethylolpropane esters which in turn show better antiscuffing properties than the pentaerythritol esters. The effect of the polarity of the molecules on the friction and wear properties of the polyol esters is discussed using a relative polarity index. Less polar polyol esters were found to have better wear and scuffing protection behavior in lubricating the Al-Si alloy. Oxidation tests in the Penn State Microreactor with Al-Si catalyst specimens showed that the polyol esters were depleted mainly by evaporation losses under an air atmosphere. A consistent trend was observed between the volatility of the polyol esters and their lubrication properties for the Al-Si alloy. Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

Production of trimethylolpropane esters of rapeseed oil fatty acids by immobilized lipase

The polyol, trimethylolpropane (2-ethyl-2-hydroxymethyl-1,3-propanediol), and a mixture of rapeseed oil fatty acid methyl esters were transesterified by immobilized lipases without additional organic solvent. The conversion to the polyol tri-ester with immobilized Rhizomucor mieheilipase Lipozyme IM 20 was about 75% after 24 h at 58°C, 5.3 kPa, with no added water, and the highest conversion of about 90% was reached in 66 h.

Quality control of paints: Pyrolysis-mass spectrometry and chemometrics

The thermal degradation of a standard (sample 1) and five resin-modified paints has been investigated by pyrolysis-field ionization mass spectrometry (Py-FIMS). The modifications simulate possible industrial disturbances: cross-linker modification (omission of methyl melamine: sample 2, replacement by benzoguanamine: sample 3), resin-reduction (acrylic resin: sample 4, polyester: sample 5) and resin-exchange (epoxy resin: sample 6). For the investigated resins, the following marker signals have been assigned: melamine ( m z 126) and methyl melamine ( m z 140); benzoguanamine ( m z 187); propenal ( m z 57) and styrene ( m z 104) for the acrylic resin; adipic ( m z 129) and phthalic acid ( m z 149) for the polyester; bisphenol A diglycidyl ether monomer ( m z 340) and dimer ( m z 624) for the epoxy resin. Apart from these resin marker signals, major pyrolysis products of the polymer backbone, like esters of trimethylolpropane units with phthalic ( m z 413, 561, 807) and adipic acid ( m z 541, 727 and homologues), and cross-linking products, e.g. between methyl melamine and trimethylolpropane ester fragments ( m z 785, 805, 825), have been identified. Using these signals, all six samples were differentiated and the origins of the modifications specified. The data were interpreted by principal component (PCA) and discriminant analysis (DA). Chemometric evolution as a means of visualizing the data enabled the reproducibilty of the measurements to be estimated and the samples to be differentiated according to the influence of their modifications. The most intense effects were assigned to the cross-linker modifications. They affected several resin signals, while other modifications showed minor effects mainly on their own marker peaks.

Biodegradable lubricants — Analysis of metalworking oils and hydraulic fluids by mass spectroscopy

AbstractBiodegradable metalworking oils and hydraulic fluids were screened for their base oil composition using a special mass spectrometric technique — direct exposure probe chemical ionisation mass spectrometry (CI(NH3)‐MS). All but one of the hydraulic fluid samples were rapeseed oil or trimethylolpropane trioleate based, the other sample being a neopentylglycol ester trimethylolpropane ester mixture. Ethylhexyl ester of rapeseed oil fatty acids (or similar) was present in some of the metalworking fluids in addition to rapeseed oil, whilst other samples were pure rapeseed oil. In several cases a trimethylolpropane/neopentylglycol ester base was found. Preliminary results for additive isolation/identification show the usefulness of preparative gel permeation chromatography.

Formation of the Neurotoxin TMPP from TMPE-Phosphate Formulations

Gas phase formation potential of the deadly neurotoxin trimethylolpropane phosphate (TMPP) from reaction in lubricant formulations containing trimethylolpropane ester (TMPE) basestock and tricresyl phosphate (TCP) additive is investigated and found to occur at temperatures of 250°-750°C. The initial formation in the gas phase is found to occur 100°C lower than previously reported. A potential substitute for TCP, T-butylphenyl phosphate (t-BPP), is also found to participate in the formation reaction at nearly the same rate as TCP, producing similar amounts of TMPP. A maximum 15 % theoretical yield of TMPP in air is observed at 550°C, while a maximum 42% yield is observed at 650°C in helium, with two-second exposures of 2 wt% phosphate additive formulations. The reaction is found to be weakly dependent on temperature, with Arrhenius activation energy estimated to be in the 20–40 kj/mol range. Minimization or replacement of TMPE or inhibition of the TMPP formation reaction, rather than restriction of phosphate additives, in synthetic ester lubricant formulations is recommended to reduce or eliminate potential TMPP formation.

Synthesis, characterization, and utilization of methacrylic esters of polyhydric alcohols

AbstractDimethacrylic esters of di‐, tri‐, and tetraethylene glycols; trimethacrylic ester of trimethylolpropane and tetramethacrylic ester of pentaerythritol were prepared by a commercially viable process in high yields and purity. These methacrylic esters were systematically characterized by infrared, 1H and 13C nuclear magnetic resonance and mass spectroscopic methods. Anaerobic adhesive compositions were made based on each monomer, and their torque strengths were compared.

High Temperature Decomposition of Military Specification L-23699 Synthetic Aircraft Lubricants

Previous investigations reported the formation of a neurotoxicant, tri methylolpropane phosphate (TMP-P) during pyrolysis of synthetic, aircraft engine lubricating oils. Employing both sealed-tube and open-to-air methods of pyrolysis, we confirmed the formation of TMP-P during lubricant pyrolysis. Rodent bioassay and GC/MS analysis were performed for detection and quanti tation of neurotoxicant production. Maximal production of TMP-P for sealed- tube pyrolysis occured after 20 min at 500°C. A comparable amount of TMP-P was formed after 5 min at 650°C in open-to-air pyrolysis of lubricants. Our examination of TMP-P production was limited to L-23699 lubricants composed primarily of a trimethylolpropane (TMP) ester base stock. The formation of TMP-P was only dependent upon the presence of an organic phosphorous addi tive and TMP. Pyrolysed lubricants composed of a pentaerythritol base did not cause neurotoxicity in mice or rats following intraperitoneal (i.p.) injection. Other toxic bicyclophosphorous ester homologues were not detected in any pyrolyzed lubricants following GC/MS analysis. L-23699 lubricants which had been operationally employed in aircraft engines under rigorous test conditions, produced no neurotoxicity when intraperitoneally administered to rats.

Production of a Bicyclophosphate Neurotoxic Agent During Pyrolysis of Synthetic Lubricant Oil

The formation of 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2.]octane-1-oxide ("trimethylolpropane phosphate"; "TMPP"; "EPTBO") from the thermal decomposition of a synthetic aircraft engine lubricant has been observed in yields ranging from 100 μg/g to over 9,000 μg/g oil. Although the exact composi tion of the oil studied is proprietary, two ingredients typically used in synthetic lubricants of this type, trimethylolpropane esters of carboxylic acids, and tricresylphosphate, are probable precursors. The production was a linear func tion of temperature over the range of 400 to 645 °C for one test system used, and showed a dramatic increase for a second set of pyrolysis conditions that in cluded higher pressure and longer heating time. Formation of decomposition products was rapid once decomposition temperatures were reached, with some TMPP production occurring within 2 minutes. The relative volatility of this syn thetic lubricant formulation compared with previously studied sources of TMPP (polyurethane foams) requires specific pyrolysis system modifications to carry out controlled decomposition studies. Worst-case conditions for decomposition and TMPP yield are discussed.

Flow activation quantities of trimethylolpropane ester.

The flow activation quantities of eight trimethylolpropane esters and two mixtures were experimentally determined at 313.2K. The relation between activation quantities and molecular structures of these esters was discussed. The activation quantities of the physical mixtures were compared with those of the corresponding chemical mixtures of the same average composition. Relations between these activation quantities were also discussed.

New polyacetal, poly(ester‐acetal) and their urethane‐modified coatings from hydroformylated linseed oil

AbstractPartly hydroformylated linseed oil, with an average of 1.3 to 3.4 meq aldehyde per gram of oil, was reacted with pentaerythritol hydroxymethyl linseed oil and trimethylolpropane in the presence of an acid catalyst to form viscous, high molecular weight polyacetals. Isophthalic acid or chlorendic anhydride‐modified polyacetals [poly(ester‐acetals)] were prepared by reacting the trimethylolpropane esters of the acids with the hydroformylated oils. Films of the products were cured at room temperature and at 140 C. These films showed good hardness as well as chemical and impact resistance. Further modification of these polyacetals and poly(ester‐acetals) by reacting the residual hydroxyl groups with an excess of toluene diisocyanate gave the corresponding isocyanate‐terminated prepolymers. Films from these prepolymers had shorter drying times and showed greater hardness than the corresponding unmodified materials.

A study of the working properties of trimethylol-propane esters as synthetic lubricating oils

1. A number of esters of trimethylolpropane with fatty acids have been synthesized, and their physicochemical properties and behavior under dynamic conditions have been studied. 2. The investigations conducted showed that among the esters synthesized there are products with high operational properties, which can be recommended as bases for lubricating materials for a wide range of temperatures and various conditions of operation with respect to frictional character.