CS247292B1 - Synthetic lubricant preparation method - Google Patents

Description

The invention relates to a process for the preparation of a synthetic lubricant, such as synthetic ester and / or polyester oil, to be used as a component of lubricating petroleum and synthetic lubricating oils, including sealing oils, as well as other special oils and greases based on both new and traditional starting materials. raw materials.

In order to meet the ever-increasing demands, both in quantity and in their reliable function under extreme conditions, as well as to increase their quality for use under normal conditions, in addition to modern second-grade oils, synthetic oils are increasingly important. These include mainly polyalkylene glycols, respectively. polyalkylethers, oligomers and low molecular weight polymers of alkenes, alkylaromates, polyphenylethers, fluorinated and chlorinated hydrocarbons, polysiloxanes, -alkyl esters as well as arylesters of silicic acids, alkyl esters as well as arylesters of trihydrogen phosphoric acid, alkyl esters of monocarboxylic acids and alkyl esters of monocarboxylic acids and alkyl esters of monocarboxylic acids (Štěpina V., Veselý V .: Lubricants and Special Oils, Veda, Bratislava 1980).

Of the alkyl esters of the monocarboxylic acids, the esters of the C ₅ -C ₁₀ monocarboxylic acids and the polyols, in particular the neoalkyl polyols, and in particular trimethylolpropane, pentaerythritol and dipetanerythritol, are of particular importance. Significant monoesters include esters prepared from 2-ethylhexanoic acid and heptanol, as well as 2-ethylhexanol and isooctadecanol. Then from iso-decanoic acid and n-hexadecanol, heptanoic acid and isononanol and isotridecanol. Diol ester oils include mainly oil prepared from dipropylene glycol and n-nonanoic acid and pelargonic acid, 1,6-hexanediol with 2-ethylhexanoic, n-nonanoic, isodecanoic and isotridecanoic acids. Of the tetraol esters, pentaerythritol esters of n-heptanoic, n-octanoic, n-decanoic, isodecanoic and isostearic acids are known.

However, there is a shortage of limited raw material resources, which also hinders the wider application of ester and polyester oils. A similar situation applies to the alkyl esters of dicarboxylic acids [Hieman, K. C., S-anford, C.R. Sci. Instr. 1, 140 (1930); Nikoronov Ε. M. and others: Sb. n-AUC. pimple. Vses. naučno-issled. inst. pererab. nefti 42, 66 (1982)] or diester oils [Vilenkin A.V. et al., Chem. i technolog, topliv 1 butts No 9, 31 (1980)].

A similar situation applies to the branched chain alkyl esters of α-neopentyl polyols as well as phenols - [Chao T. S. et al., Ind. Eng. Prod. Res. Dev. 22, 357 (1983)], such as e.g. esters formed from 2-methylbutyric acid and pentaerythritol or 2-ethylhexanoic acid with trimethylol-1-propanoate.

These and other technical problems are solved by the present invention.

According to the present invention, a process for preparing a synthetic lubricant based on oxygenated organic compounds by esterification, transesterification and / or polyesterification at a temperature of 80 to 280 ° C, typically associated with a separation into at least two fractions, is performed such that the by-product from cyclohexanone and / or cyclohexanol by oxidation of cyclohexane, it is esterified and / or re-esterified with at least one aliphatic alcohol C1 to C _4, separating the fraction boiling at 100 to 450 ° C, calculated to atmospheric pressure, and treatment with at least one monohydric alcohol C _{(i-C 2} o, preferably C ₈ to C _T4, and / or at least one diol, The sealed, optionally unconverted and other volatile fractions are separated, the product obtained being treated and / or separated under reduced pressure, preferably by evaporation in a film or by molecular distillation.

An advantage of the process according to the invention is its technical simplicity and the extension of the range of starting raw materials for the production of ester and polyester oils, the technical utilization of hitherto low-valued by-products from the oxidation of cyclohexane. Furthermore, sufficient flexibility of both the reaction conditions and the feedstocks is possible to produce at least two types of synthetic lubricants or lubricating oil components, lubricants, greases or sealing oils and the like at the same time in one production facility.

The oxygen by-product of oxidation of cyclohexane to cyclohexanone and / or cyclohexano-1 usually consists of monocarboxylic acids (formic, acetic, propionic, butyric, valeric, caproic, ε-hydroxycaproic, and others) and their esters, η in particular cyclohexyl, lactones, dicarboxylic acids (mainly adipic, glutaric, succinic acids) and their monoesters and diesters, in particular cyclohexyl, optionally with admixtures of cyclohexanol and cyclohexanone.

Group-analysis, respectively. An analysis of the functional groups of the oxygenated organic product generally results in an acid number = 230 + 50 mg KOH / g; saponification number = 420 + 25 mg KOH / g; hydroxyl value - 160 + 60 mg KOH / g; bromine number = 20 + 10 g Br / 100 g; water - 0.1 to 10 washes. wt.

In particular, the hydroxyl number, the higher the acidity and saponification number, may be lower than the values indicated. Physical refining is carried out by means of adsorbents (activated charcoal, bleaching earth, etc.) or by extraction with selective solvents. Chemical refining is accomplished by hydrogenating the double bonds on conventional hydrogenation catalysts based on medium, nickel, cobalt, iron, platinum, palladium, sulfur dioxide, at elevated hydrogen pressure and temperatures of 60-220 ° C.

Suitable diols are, in addition to monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, in particular 1,4-butanediol, 1,6-hexanediol, decanediol, dodecanediol, hexadecanediol, polypropylene glycol, neopentyl glycol, ethylene glycol di-ethylene copolymer, and the copolyadexylene propylene ethylene copolymer. winter-split fat or partially esterified pentaerythritol and dipentaerythritol.

The trioles include, in addition to glycerol, mainly trimethylolpropane, etc., the tetraols are pentaerythritol alone or also containing dipentaerythritol, which is in fact already hexaol.

The monovalent aliphatic alcohols in addition to the conventional aliphatic alcohols of the present invention may also include the addition or polyaddition ethylene oxide product as well as the propylene oxide to the aliphatic alcohols.

To accelerate esterification, pre-esterification as well as polyesterification, it is suitable to use catalysts which are strong mineral acids (sulfuric acid, phosphoric acid, etc.), organic sulfoacids (benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, dodecylbenzenesulfonic acid polymer), and in particular such as sulphonated, styrene-divinylbenzene resin, in particular the heat-stable cationite-sulfopolyphenylene ketone, which can be used for esterifications and polyesterifications even at temperatures of 180-220 degrees Celsius. , tin, antimony, uranium, zirconium, manganese, and molybdenum.

The esterification, transesterification and polyesterification may be carried out in an inert atmosphere, typically in the presence of nitrogen or carbon dioxide. Similar, especially from the point of view of the final product, it is suitable to do the separation of products without oxygen access. The distillation of the products is generally carried out under reduced pressure, most preferably on a film evaporator or by molecular distillation.

Synthetic lubricants (synthetic liquid and greases, sealing oils and other specialty oils) can only be applied exceptionally, similar to the known ester or polyester oils, without further additives and treatments. Depending on the intended application, it is suitable to add known refining additives, such as antioxidants, metal deactivators, detergents and dispersants, anticorrosive agents, antifoams, emulsifiers and the like. In addition, they can be combined with both petroleum and other synthetic lubricants.

The process according to the invention can be carried out mainly discontinuously but also semi-continuously and continuously.

Further details of the process as well as other advantages are evident from the examples.

Example 1

An autoclave of a volume of 1.2 ^dm3 equipped with an electromagnetic overhead stirrer, temperature measurement and control, including the heating of accessories, weigh 240 g of methanol and 304 g of dark brown by-products from the production cyklohexančnu and cyclohexanol by oxidation of cyclohexane, with these characteristics: dynamic at 20 ° viskozba C = 538 mPas; density at 20 ^° C = 1119 kg. m ^-3 ; pour point - = —2Π ° C; acid number = 202.1 mg KOH. . g ~ '; saponification number = 409.0 mg KOH. . g ^J ; bromine number = 22.3 Br. 100 g ^-1 ; OH content = 2.9% by weight; water = = 8.4 wt.

The autoclave is then sealed, removed from the air, nitrogen is introduced and the contents are heated to 210 ° C with stirring, the pressure in the autoclave rising to 4.5 MPa, and under these conditions the esterification and partly the transesterification takes 100 min. After completion of the reaction, the reaction product obtained is distilled at atmospheric pressure at a temperature of 50 to 110 ° C in order to distill off the reaction mixture and the feed water and unreacted methanol. Then, the product is distilled under reduced pressure (1.3 kPa) at 80-140 ° C, distilling 183 g of a fraction which mainly contains the methyl and dimethyl esters of the acids contained in the flood by-products of the distillation residues from the production of cyclohexanol and whether free or in the form of cyclohexyl esters.

In a similar procedure, 366 g of the methyl ester fraction were prepared together with another batch.

The viscous dark brown distillation residue remaining in the flask after distillation of the ester fraction (136 g per batch) is a mixed ester oil having a pour point of -37 ° C, suitable as an additive to lubricating greases but also as a sealing oil for gas tanks. It can also serve as an additive lubricant for open gears.

366 g of the methyl ester fraction, 579 g of 2-ethylhexanol and 1.2 g of tetrabutyl titanate as a transesterification catalyst are weighed into a 2 dm ³ esterification flask equipped with a downstream condenser. The transesterification reaction lasts 4 h at 160 to 185 degrees Celsius and is carried out while purging the reaction mixture with nitrogen at a rate of 15 dm ³ · h ^-1 . During the transesterification is separated off from the reaction of methanol and after the transesterification under reduced pressure (1.3 kPa) and a temperature of 110 C. ⁿ has collected 288 g of unreacted 2-ethylhexanol and the pot remains a mixture of 580 g of esters of light yellow color · Acid value 1.3 mg KOH. g ^_1 ; saponification value 298.3 mg KOH.

. g- ¹ , density 969.0 kg.m ^-3 , with an average molecular weight of 309 g. mol- ¹ . It is miscible with both petroleum oil and gasoline, and is well suited as a component of semi-synthetic oil for two-stroke engines and multigrade oils.

Example 2

In a similar manner to Example 1, 386 g of the methyl ester fraction was prepared from the by-products of cyclohexanone / cyclohexanol by oxidation of cyclohexane. However, this is, in contrast to 2-ethylhexanol, transesterified at 180 to 200 ° C with a mixture of 800 g of primary aliphatic alcohols Ο _Η to C 13. 788 g of a slightly yellowish ester oil having an acid number of 0,9 milligrams of KOH.g ^-1 and an average molar mass of 370 g.mol ^{-1 are obtained} , saponification number

282.1 mg KOH. g ^-1 and a density of 967.0 kg. m ^-3 . Example 3

From the by-products of oxidation of cyclohexane to cyclohexanol and cyclohexanone, a mixture of dimethyl esters, consisting of 61.6% by weight, is isolated after refining with a small amount of nitric acid, esterification and distillation. % of dimethylglutarate and 39.1 wt. dimetyljantarátu. From this mixture, 800 g is added to a 4 dm ³ flask equipped with a stirrer, thermometer, downstream condenser and distillate separation, then 1600 g of 2-ethylhexanol, 4.0 grams of tetrabutyl titanate and 4.0 g of sodium hypophosphite are added. The transesterification at 68-165 ° C takes 7 h. 340 g of methanol are distilled off during the reaction. The crude reaction product was further distilled under reduced pressure (1.59 kPa) while 216 g of 2-ethylhexanol was distilled off.

The flask residue, synthetic ester oil, in an amount of 1,822 g, has an acid number of 1.26 milligrams of KOH.g ^-1 ; saponification number

316.1 mg KOH.g ^-1 , bromine number = 0.1 g Br. 100 g ^-1 ; OH content of 0% by weight; the density at 20 ° C is 930.5 kg.m ^-3 and the kinematic viscosity at 100 ° C is 2.14 mm ² · s ^-1 ; flash point 193 ° C and pour point —61 degrees Celsius.

Example 4

As in Example 1, only the esters and dimethyl esters are hydrotreated on a truncated heterogeneous scaffold catalyst (Raney-med) at 170 + 5 ° C and 0.4 g catalyst loading before pre-esterification. cm ³ , h ^-1 and the molar ratio of 1: 6 monoesters and diesters to hydrogen injected. Unlike unrefined, the ester thus treated, unlike refined, gives 566 g of an ester oil, almost colorless with an acid number of 1.10 mg KOH.g ^-1 , saponification number 293 mg KOH.g ^-1 , density at 20 ° C 964 kg. m ³ and bromine number ~ 0 g Br. . 100 g ¹ .

Example 5

To a 2 dm ³ flask was weighed 1000 grams of methyl and dimethyl esters prepared as described in Example 1. 60 g of 1,4-butanediol, 1200 g of 2-ethylhexanol and 1.4 g of tetrabutyl titanate as catalyst were added. The transesterification and, in part, the polyesterification takes place at a temperature of 180 to 210 ° C for 10 h and the product is subjected to molecular distillation. This gives a viscous light ester and partly polyester oil in an amount of 824 g, having an acid number of 0.6 mg KOH.g ^-1 and a kinematic viscosity at 100 ° C of 4.3 mm ² . . s ^J , saponification number 284 mg KOH.g ^-1 , density at 20 ° C 962 kg. m ^-3 .

Example 6

Weigh 1 200 g of methyl ester fraction, boiling point 80 to 140 ° C, 1,3 kPa (acid number 9,75 milligrams KOH.g) into a 2-dm ³ -necked flask equipped with a stirrer, a contact thermometer with a temperature regulator and a condenser. ^-1, hydroxyl value = 190.7 mg KOH. g ^-1, saponification value = - 475.8 mg KOH.g ^-1, bromine number- = Br, 8.3 g. 100 g, H₂O = 0.2% density at 20 ° C - 1087.5 kg m ^-3 , dynamic viscosity at 25 ° C = 5.47 mPa · s prepared by vacuum distillation from the crude ester product obtained by pressure esterification of by-products - distillation residues from the production of cyclohexanone (and cyclohexanol) by oxidation of cyclohexane with methanol.

160 g of diethylene glycol and 0.84 g of tetrabutyl titanate are added. By esterification, transesterification and polyesterification at 200 ° C for 7 h, 792 g of the product with hydroxyl value = 0 mg KOH.g ^{-1 were obtained} ; acid number - 2.1 milligrams KOH.g ^-1 ; saponification number = - 490.5 mg KOH.g ^-1 ; dynamic viscosity at 25 ° C = 256.2 mPa. with; density d ₄ ²⁰ = = 1114.2 kg. m ^-3 , which is mixed with gear oil PP-7 in a weight ratio of 1.5: 8.5.

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Claims (2)

Process for the preparation of a synthetic lubricant based on oxygenated organic compounds by esterification, transesterification and / or polyesterisation at a temperature of 80 to 280 ° C, usually associated with a separation into at least two fractions, characterized in that the by-product from the production of cyclohexanone 1a / adobo cyclolihexaimol oxidáciiou cyclohexane is esterified and / or transesterified with at least one aliphatic alcohol C _t to C ₄₎ separating the fraction boiling at 100 to 450 ° C, calculated to atmospheric pressure, and treatment with at least one monohydric alcohol C _fi to C ₂ o, p preferably, C 8 to C 12 from "and / or at least one diol to tetraol" is esterified and / or does not esterify and polyesterify. 2. Process for preparing a synthetic lubricant according to claim 1, characterized in that after esterification and / or transesterification of the oxygen-containing by-product from the production of cyclohexanone and / or cyclohexanol by oxidation of cyclohexane with at least one aliphatic alcohol or alcohols, a fraction of boiling point of 100 to 450 ° C is separated, preferably refined by adsorption, extraction and / or catalysed hydrogenation of the double bonds and after pre-esterification and / or doesterification and polyesterification the displaced, eventually unconverted alcohols and other volatiles are separated wherein the product obtained is treated and / or separated under reduced pressure, preferably by evaporation in a film or by molecular distillation.