Dibasic Acid Esters Research Articles

Sustainable process for the production of symmetrical dibasic acid ester-basedthermal energy storage materials from lipids

Oleochemical-based long-chain diesters are potential organic phase change materials convenient for thermal energy storage. The development of efficient and green methods is an important requirement for the preparation of these environmentally friendly compounds, which also are finding wide industrial application. Thus, in the present work, a series of dibasic acid esters were synthesized through ionic liquid catalyzed scalable chemical esterification or transesterification reactions in a solvent-free medium. The starting compounds, dicarboxylic acids or their methyl esters and fatty alcohols or cholesterol, were reacted in the ratio of 1:2 respectively and the synthesized esters were characterized by FT-IR, $^{1}$H NMR, and $^{13}$C NMR.

INVESTIGATION OF INFLUENCE OF ESTER STRUCTURE ON THERMAL-OXIDATIVE OILS STABILITY

This work aims are analysis the influence of the structure of esters on their thermo-oxidative stability. Then we select the composition of additives to improve the oxidation properties of aviation turbine engines. As the main method we used the following study: Standard Test Method for Corrosiveness and Oxidation and Stability of hydraulic oils, aircraft turbine engine lubricants and other highly refined oils ASTM 4636-99. It has been found that the esters of dicarboxylic acids and aliphatic alcohols have a low thermal oxidative stability, which may result in frequent change in the oil lubrication system and washing with gasoline or jet fuel. Thus, compositions based on esters of dibasic acids and aliphatic alcohol are good plasticizers having abrasion resistance and frost resistance. Thought they have low pour points and high viscosity index. As a basis for aviation oil hindered esters are recommended, which have high thermal oxidative stability. In the industry esters obtained by etherification of the mixture of acids and a polyhydric alcohol are used. Esters are optimal on its viscosity-temperature properties which were obtained in the reaction of etherification of pentaerythrit and trimetilolpran alcohols, and mixtures of hexane, heptane, nonanoic, octanoic acids. Physico-chemical parameters of esters are improved with increasing in number of functional groups in the molecule. The reason for this is that the esters were obtained by the reaction of etherification of n-C9 acids with pentaerythritol alcohols which forms a sterically hindered ester. This structure has no hydrogen atom in the molecule in β-position, which prevents the formation of cyclic hydrocarbons. However, to get oils with high performance require it is necessary to add additives. Therefore, domestic and foreign literatures and requirements for oxidation stability were analyzed. Based on these data the main requirements were formulated for oil composition of aircraft gas turbine engines. As the results of the oxidative stability testing it were found that to obtain oil which satisfies to all modern requirements for thermal oxidative stability, it requires the use of complex of antioxidants of phenolic and amine types. Forcitation:Tonkonogov B.P., Bagdasarov L.N., Popova K.A., Agabekov S.S. Investigation of influence of ester structure on thermal-oxidative oils stability. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 73-79

Development of an environmentally acceptable volatile organic compounds recovery and reuse system based on vacuum spray flash with dibasic acid esters as absorbents

We used dibasic acid esters as the absorbent for a volatile organic compounds (VOC) recovery and reuse system geared mainly toward VOCs from painting and presswork. The system consists of three elements: absorption using dibasic acid esters, separation by vacuum spray flash method, and recovery by condensation. The concentration of both ethyl acetate (EtAc) and isopropyl alcohol (IPA) decreased around 90% at room temperature. Vacuum spray flash was found as a useful process for cost-effective and energy-effective VOC removal system. The difference in the dissolubility parameters (Hansen constant) between dibasic acid esters and VOCs and the boiling point of VOCs was the main contributor to the separation behavior.

Synthesis of unsaturated dibasic acid esters from five-, six-, and seven-membered cycloalkanones

A new route to diesters of symmetrical octene-, decene-, and dodecenedioic acids was proposed. The ratio of the cis/trans-isomers was 1: 4. The synthesis involved oxidative splitting of five-, six-, and seven-membered cycloalkanones with hydrogen peroxide into the corresponding ω-alkenoic acids followed by esterification and metathesis over Re2O7/B2O3-Al2O3-SnMe4.

Enzymatic Synthesis and Evaluation of Surface Active Properties of Di-Basic Acid Esters of Poly-ethylene Glycols

The present work has synthesized two polyethylene glycol (PEG) esters with two di-basic acids by bioesterification process and has investigated the interface properties like interfacial tension, surface excess concentration, minimum surface area per mole and as well as the Gibbs adsorption and thermodynamic behavior of micelle formation for the PEG-400 esters of the two acids. The esterification reaction was carried out by agitating the reactants in different molar ratios with Mucor miehei (RMIM) lipase enzyme at 70-75°C for 7 hours and 2 mm of Hg pressure. The conversion of PEG to esters ranged from 40-64% depending on the molecular size of di-basic acids.

Esters of dicarboxylic acids as additives for lubricating oils

Five samples of dibasic acid esters with varied chemical structures were synthesized. These included didecyl carbonate, didecyl adipate and didecyl sebacate as well as modern oligomeric esters of adipic acid and sebacic acid. These esters were tested in terms of their suitability as additives of fully synthetic engine oils. It was noted that an addition of 10% of the respective esters to oils based on polyalphaolefins led to an improvement of their properties. The pour point of the oils as well as their low temperature viscosity were reduced. The viscosity index rose and oil lubricity improved. Esters of oligomeric structures synthesized by the transesterification of dimethyl adipate or dimethyl sebacate with a mixture of neopentyl glycol and decanol showed particularly suitable properties. The tested esters were compatible with the other oil components, forming a stable solution in a wide temperature range.

Hydrogenation of Dicarboxylic Acid Diesters to Corresponding Dialdehydes over ZrO<sub>2</sub> Based Catalysts (Part 1) Reactivity of Various Dicarboxylic Acid Diesters

Dimethyl terephthalate was hydrogenated over ZrO 2 catalyst in the vapor phase to form terephthalaldehydic acid methyl ester and terephthalaldehyde as the major products. The reactivity of the three regioisomers of benzenedicarboxylic acid dimethyl esters to hydrogenation was in the order, terephthalic > isophthalic >> phthalic. The low reactivity of dimethyl phthalate is probably due to the mutual steric hindrance of the two vicinal methoxycarbonyl groups and to catalyst deactivation caused by strong adsorption of the intermediates of dimethyl phthalate on the catalyst surface. Formation of terephthalaldehyde by hydrogenation of terephthalaldehydic acid methyl ester suggested that the hydrogenation reaction of dibasic acid diesters proceeds via successive reduction of the ester groups to formyl groups. Alicyclic acid diester dimethyl 1,4-cyclohexanedicarboxylate was also converted into the corresponding mono- and dialdehyde in a similar way. However, aliphatic dibasic acid esters such as dimethyl glutarate and dimethyl adipate were not hydrogenated at all. Modification of ZrO 2 by Cr, In or Zn improved the catalyst activity. Maximum dialdehyde selectivity in the hydrogenation of terephthalaldehydic acid methyl ester reached 72.4% by using Zn modified ZrO 2 catalyst (atomic ratio Zn/Zr = 5/100).

Highly Anomer- and Regio-selective Transesterification Catalyzed by Alkaline Protease from Bacillus subtilis in Organic Media

Abstract Highly anomer-selective-6(6′)-acylation reactions from anomeric mixtures of several mono- and disaccharides with divinyl dicarboxylates ranging from 4 to 10 carbon atoms were catalyzed by an alkaline protease from Bacillus subtilis in pyridine. A series of new pure α-anomeric polymerisable vinyl sugar esters of dibasic acids were synthesized in good selectivity and yields.

Total vegetable oil greases

AbstractA grease has two major constituents, namely, a lubricant, that performs the function of lubrication; and a gellant, that provides a solid continuous phase, occludes the lubricant, and gives apparent physical structure to the grease. Generally, the gellant is 5–30% and the lubricant 65–90%, additives and fillers making up the rest. In conventional greases, the gellant is a vegetable oil soap, and the lubricant is a liquid oil of petroleum origin or is a synthetic. Such greases have limited biodegradability, because the major constituent, i.e., the lubricant, is normally not biodegradable.In total vegetable oil grease, both the gellant and the lubricant are derived from vegetable oils, giving a grease of potentially high eco‐compatibility. Esters, dibasic acid esters, and alkylated esters of vegetable oil are known to be high‐quality lubricants. These can be used with soap stocks prepared from vegetable oils to give a grease of total vegetable oil origin.The vegetable‐oil based lubricants and soaps are prepared separately and combined in appropriate proportions to give a grease of the required specifications. Alternatively, esterification and saponification can be carried out simultaneously to give a grease of the desired specifications, where an alkali will be the catalyst for esterification, and reactant for saponification. In this paper, the process parameters, and kinetics of these simultaneous reactions are discussed. The results of experimental evaluation of some of these greases are also presented.

Optico-mechanical properties of heterogeneous crosslinked systems based on ED-20F epoxide oligomer and diallyl esters of dibasic acids

The special structural features of crosslinked polymers, the structure of which was formed in a mixture of reagents having different hardening mechanisms is studied. The effect of the heterogeneity of the system on the birefringence and deformability of the specimens during the creep period is followed. Mutual penetration in the systems studied takes place in the inter-globular region, when the polyester concentration exceeds 17–20 wt.%.

Half esters of dibasic acids as additives in water‐based cutting fluids

AbstractSeveral half esters from long chain dibasic acids were prepared, and corrosion and lubricity tests for these products as water‐based cutting fluid additives were made. Triethanolamine salts of half esters of sebacic acid and dodecanedioic acid showed effective rust‐inhibiting and anti‐wear properties for water‐based cutting fluids.

Some synergistic antioxidants for synthetic lubricants

Oxidation stability is a major requirement for all lubricants. It is even more important for synthetic lubricants used in aircraft gas turbine engines, owing to the high oil temperature and air exposure. Two basic means are available to improve oxidation stability of synthetic lubricants: choice of base fluid and use of antioxidants. It is well known that fluids such as polyphenyl ethers are much more oxidatively stable than fluids such as dibasic acid esters. Discussions of the effect of the nature of the C-H bond on oxidation stability have been made in our previous paper and by other authors such as Ingold and Sniegoski. However, the choice of base stock is severely limited by cost and other considerations such as volatility, flow characteristics, etc. When the choice of base fluid has been made, use of a better antioxidant is the only avenue available to improve the oxidation stability of the lubricant. This paper describes some of the antioxidant systems which were found effective for ester type synthetic lubricants. The esters used included those based on dibasic acids, neopentylpolyols and complex esters. The systems discussed include one or two primary antioxidants and a synergistic antioxidant. The primary antioxidant used included N-phenyl-..capmore » alpha..-naphthylamine (PANA) and p,p'-dioctyldiphenyl amine (DODPA). Synergistic antioxidants which were found to improve the effectiveness of the primary antioxidants include alkali metal compounds, aromatic diamines, heterocyclic amines, hydroxybenzophenones, and certain S and P compounds.« less

Synthesis and Properties of Bis (aminimides) Containing Ether Linkages

Several dibasic acid esters containing oxyalkylene units (-OCH2-, -OC2H4-, unit number; 15) were treated with aminimines derived from alkyl (C8C12) glycidyl ethers and 1, 1-dimethylhydrazine, giving a new series of bis (aminimides) with the yields of 3040%. The introduction of ether linkage caused a decrease in melting point and Krafft's point of the bis (aminimides). The lower members regarding m (m<3) were more soluble in water and showed high surface activity, but the higher members were less soluble. Cloud point and cmc of these surfactants were found to decrease with increasing m.They were effective phase-transfer catalysts for aqueous potassium iodide-octyl bromide two phase reaction. Their efficiency increased with increasing m. The efficiency of a higher member (m=5) was much greater than that of dibenzo-18-crown-6 and was close to that of dicyclohexyl-18-crown-6.

Fat‐Based synthetic lubricants

AbstractSynthetic lubricants derived from fat‐based materials are almost exclusively esters of the following type: (a) mono and dibasic acid esters, e.g., laurates, stearates of short chain aliphatic alcohols, azelates and sebacates of oxo alcohols; (b) polyalkylene glycols and glycol esters, e.g., triethyleneglycol dicaprylate caprate and others; (c) branched polyol or nucleic polyol esters derived from pentaerythritol or trimethylol alkanes and saturated short chained acid of the C6, C8, C9 type; (d) triglycerides, specifically tailored by the rearrangement of two or more naturally occurring triglycerides. Among the unique but desirable characteristics of synthetic lubricants are: good lubricity, minimum viscosity change with temperature (high VI), low temperature fluidity, high thermal and oxidation stability, low volatility, excellent additive response, seal and gasket compatability and high fire and flash points.

Corrosion Test of Derivatives of Aromatic Carboxylic Acids and Dibasic Acids

Various alkyl benzoic acids and half esters of dibasic acids were prepared. Corrosion test for cutting fluids characterization of these compounds were examined. Triethanol amine salts of mono oleil phthalate and acids alkyl (methyl, butyl, pentyl, hexyl and octyl) benzoic acids have excellent properties.

Synthesis of bis-(p-carballyloxyphenyl) esters of aliphatic and aromatic dibasic acids

The mixed esters of dibasic acids were synthesized by the condensation of allyl p-hydroxybenzoate with the acid chlorides of aliphatic and aromatic dibasic acids, some of which form a thermotropic liquid crystalline phase of the nematic type.

Spatial structure and conformational state of dilupinine esters of dibasic acids

1. The conformational states of dilupinine esters of dibasic acids and their protonated forms, and also their dimethiodides, have been studied by PMR spectroscopy.

Degradation of humic acid in a sodium sulphide solution

Sixty per cent of the products from the degradation of humic acid (extracted from a Fenland organic soil) with a 10% sodium sulphide solution under autoclave conditions for 2 h at 250 °C were soluble in ether or ether—ethanol solutions. Several neutral volatile degradation products were observed by gas—liquid chromatography, and ethyl esters of dibasic acids and possibly similar esters of phenyl propionic acid derivatives were isolated from the ether-soluble acidic degradation products. This technique is promising and worthy of further application.

Cyclopolymerization of divinyl esters of dibasic acids and structure of poly(vinyl alcohol) derived from the polymers

AbstractDivinyl esters of dibasic acids, CH2CHOCO(CH2)n−2COOCHCH2, n = 2–10, were synthesized and polymerized with a radical initiator, and the structure of poly(vinyl alcohol)(PVA) derived from the polymers were studied. The cyclopolymerizability of these monomers was nearly equal to or less than that of divinyl carbonate which was previously reported, and the extent of cyclization was 15–65%. All the monomers yielded gelled polymers. The monomers which are to yield even‐membered rings tend to cyclopolymerize more easily than those of odd‐membered rings. PVA derived from these polymers showed a similar structure with respect to 1,2‐glycol content and stereoregularity to that from poly(vinyl acetate).

Thermal Characteristics of Some Organic Esters

Experience has shown that the principal limiting factor in the use of esters of organic acids as lubricants is the stability of these materials in a high-temperature environment. Comparisons of the thermal behavior of different types of organic acid esters have, in many cases, been made in all glass test equipment. A more comprehensive quantitative evaluation of the thermal reaction of these materials indicates a somewhat different relative behavior in systems containing metals. Analysis of the original ester and the product after thermal exposure using temperature-programmed gas chromatography allows one to determine the amount of ester degraded and to characterize the materials formed in the reaction. Materials investigated include dibasic acid esters, beta-blocked esters (polyols plus monobasic acids), and simple monobasic acid esters. A definite effect of catalyst metals in the system is indicated. The effect of the presence of metals is shown to differ with the type of ester. The critical nature of the alcohol group (beta carbon) is illustrated by several tests using methyl esters.