RU2361904C1 - Synthetic lubricating oil base - Google Patents

Abstract

FIELD: fuel systems.

SUBSTANCE: proposed synthetic lubricating oil base contains 33% to 50% by weight of the product of etherifying pentaerythritol by the mix of valerianic and pentyl formic acids taken in molar ratio of 1:1 to 1:3, the balance approximating to 100% by weight of the product of etherifying di-trimethylolpropane by the mix of valerianic and pentyl formic acids taken in molar ratio of 1:1 to 1:3.

EFFECT: improved low-temperature properties of oil, possibility of using readily available cheap stock.

3 tbl, 4 ex

Description

The invention relates to compositions of a base synthetic oil, in particular to a synthetic lubricant oil containing a mixture of pentaerythritol (PE) and di-trimethylolpropane (di-TMP) esters based on a mixture of valerianic (C ₅ ) and caproic (C ₆ ) acids, and can be used to obtain aviation ester oils.

In world practice, a synthetic base oil is prepared on the basis of the product of pentaerythritol esterification with a mixture of individual monocarboxylic acids C ₅ -C ₁₀ taken in various mass fractions [Yaffe Roberta Pat 4216100 US, aug, 5, 1980]. The disadvantage of the claimed method for producing the base of synthetic oil is the use of expensive and inaccessible monocarboxylic acids with an odd number of carbon atoms: enanthic (C ₇ ) - up to 30% and Pelargonic (C ₉ ) - up to 20%.

Lower monocarboxylic acid pentaerythritol esters (valerianic and caproic), despite the low pour point, are not considered as potential base synthetic oils due to their low viscosity at 100 ° C (about 4 mm ² / s) and insufficient viscosity index (about 120 ) and unsatisfactory lubricating properties [M.M.Kukovitsky, R.N. Khairullina, T.A. Ismagilov, TA. Ivanova. // NTIS "Oil Refining and Petrochemicals". - 1986. - No. 11. - C.18-20].

On the other hand, esters of di-trimethylolpropane (di-TMP) and lower monocarboxylic acids are known, having high thermal, thermo-oxidative and hydrolytic stability, good lubricating properties and low pour point. The presence in the alcohol molecule of a simple ether bond provides a gentle viscosity-temperature dependence of the obtained esters (high viscosity index). However, esters of di-TMP and lower monocarboxylic acids (butyric, C ₄ , and valerianic, C ₅ ) are characterized by relatively high viscosity at 100 ° C and excessively high viscosity at low temperatures (table 1) [Virgil W. Gash, Pat 3681440 US, aug. 1, 1972]. Due to these shortcomings, they cannot be used as the basis for synthetic lubricating oil for aircraft gas turbine engines.

The closest in technical essence and the achieved results is the basis of synthetic lubricants (for example 36/1, B3-V, L3-240) - "Ether-2", designed for aircraft gas turbine engines (GTE) operating in a wide temperature range in various friction modes at high loads. To obtain "Ether-2", pentaerythritol esters and FFA synthetic fatty acid fractions (C ₅ -C ₉ ) were used [M. Kukovitsky and others // Oil refining and petrochemicals. - 1978. - No. 9. - S.8-9]. Fraction FFA (C ₅ -C ₉ ) in our country was obtained by the oxidation of petroleum paraffins. The fraction had approximately the following composition of acids (wt%): butyric (3.8), valerianic (15.4), caproic (28.6), enanthic (24.1), caprylic (15.8), pelargonic (8 , 7), capric (3.0), undecane (0.6). [Kukovitsky M.M: abstract. dis. for the degree of candidate of technical science: Sverdlovsk: Ural branch of the USSR Academy of Sciences, Institute of Chemistry. - 1968. - P.19.]

In 2002, for environmental reasons, the production of FFA (C ₅ -C ₉ ) was stopped; as a result, ester oils on this basis of domestic production are not currently produced.

The objective of the proposed technical solution is to expand the raw material base to obtain the base of synthetic lubricating oil, which is not inferior in terms of the basic physical and chemical parameters of Efir-2, based on pentaerythritol and dimethylolpropane esters and available low molecular weight monocarboxylic acids.

The problem is achieved in that the base of the synthetic lubricating oil, which is a mixture of the products of the esterification of polyhydric alcohols, including the product of the esterification of pentaerythritol with a mixture of monocarboxylic acids, according to the invention, the product of the esterification contains the product of the esterification of pentaerythritol with a mixture of valerianic and caproic acids taken in a molar ratio of 1: 1 up to 1: 3, and additionally contains the product of the esterification of di-trimethylolpropane with a mixture of valerianic and caproic acids in the same molar elations the following component ratio, wt.%:

pentaerythritol esterification mixture valerianic and caproic acids 33-50 esterification product of di-trimethylolpropane a mixture of valerianic and caproic acids the rest is up to 100%

The proposed composition of the base of synthetic lubricating oil allows the base to be obtained by mixing pentaerythritol esters and a mixture of valerianic and caproic acids, and di-trimethylolpropane esters with the same acids, which meets the basic physicochemical requirements for the B-3B ester oil base (" Ether-2 ”), and surpasses it in some indicators, using affordable and inexpensive raw materials, and can be used to obtain aviation ester oils.

All esters used to form the base of synthetic lubricating oil are prepared according to known technology. A three-necked flask equipped with a mechanical stirrer, a Dean-Stark trap and a reflux condenser was charged with the calculated amount of neopentyl polyols and monocarboxylic acids. Monocarboxylic acids are used with a 20% excess. The reaction is carried out without a catalyst for 12 hours at a temperature of 180 ° C. The reaction water is removed using an azeotropic agent, o-xylene. After the reaction, o-xylene and excess acid are distilled off in vacuo. Removing acid residues is carried out using anion exchange resin AB-17-8 hours at a temperature of (60-80) ° С for 6 hours. The amount of anion exchange resin is (5-10)% by weight of the product (depending on the acid number of the product after vacuum distillation) . The yield of purified products is on average 97% of the calculated value.

The properties of the synthesized PE and di-TMP esters based on a mixture of C ₅ and C ₆ acids taken in a molar ratio of 1: 1 to 1: 3, used as starting components for the preparation of basic synthetic aviation oil, are shown in Table 2.

Samples of the synthesized esters are mixed in various mass ratios and incubated for 1 h at a temperature of 60 ° C with constant stirring.

Examples of the preparation of mixtures of PE and di-TMP esters based on C ₅ and C ₆ acids taken in various molar ratios to obtain a base for synthetic lubricating oil.

Example 1. Samples of the products of esterification 1 and 2 are mixed in a mass ratio of 50:50 (1: 1) and incubated for 1 h at a temperature of 60 ° C with constant stirring. The properties of the resulting mixture are shown in table 3, meet the requirements for "Ether-2" (prototype).

Example 2. Samples of the products of esterification 3 and 4 are mixed in a mass ratio of 67:33 (2: 1) under the same conditions as in example 1. The mixture does not meet the requirements for "Ether-2" (prototype) in terms of viscosity at + 100 ° C.

Example 3. Samples of the products of esterification 3 and 4 are mixed in a mass ratio of 50:50 (1: 1) analogously to example 1. The mixture meets all the requirements for "Ether-2" (prototype) and significantly exceeds them in terms of low temperature viscosity.

Example 4. Samples of the products of esterification 3 and 4 are mixed in a mass ratio of 33:67 (1: 2) under conditions similar to example 1. The mixture has higher viscosity values over the entire temperature range studied than the mixture obtained in example 3, but not goes beyond the requirements for "Ether-2" (prototype).

Thus, the basis of the synthetic lubricating oil is claimed, which meets or exceeds the requirements for the base of the B-3B ester oil - “Ether-2”.

Table 1 Acid Kinematic viscosity of di-TMP ester, mm ² / s, at temperature, ° С one hundred 40 Minus 40 Oil 5.76 34.60 20966 Valerianova 5.62 30.70 11366

table 2 Sample Polyhydric alcohol The ratio of acids, moths (valerian: kapron) Kinematic viscosity, mm ² / s, at temperature, ° С Viscosity index Pour point, ° C +100 +40 - 40 one PE eleven 4.05 18.32 4942.9 212 <-60 2 Di-TMP eleven 6.19 34.50 20843.7 130 <-60 3 PE 1: 3 4.12 18.54 4484.7 125 <-60 four Di-TMP 1: 3 6.06 31.93 13589.7 139 <-60 Table 3 Example The ratio of products of esterification, wt.% Kinematic viscosity, mm ² / s, at temperature, ° С Viscosity index Pour point, ° C +100 +40 - 40 one 50:50 4.99 25.04 7151.6 127 <-60 2 * 67:33 4,53 22.08 6128.7 120 <-60 3 50:50 4.95 23.12 7024.6 144 <-60 four 33:67 5.30 26.44 8959.2 138 <-60 "Ether-2" - a prototype > 4.85 Not the norm. <10600 Not the norm. <-60 * - an example outside the declared area

Claims (1)

The basis of synthetic lubricating oil, which is a mixture of esterification products of complex alcohols, including the product of esterification of pentaerythritol with a mixture of monocarboxylic acids, characterized in that the product of esterification contains the product of esterification of pentaerythritol with a mixture of valerianic and caproic acids, taken in a molar ratio from 1: 1 to 1: 3, respectively, and additionally contains the product of the esterification of di-trimethylolpropane with a mixture of valerianic and caproic acids, taken in a molar ratio of 1: 1 to 1: 3, respectively Often, in the following ratio of components, wt.%:
pentaerythritol esterification product a mixture of valerianic and caproic acids 33-50 esterification product of di-trimethylolpropane a mixture of valerianic and caproic acids the rest is up to 100