CS238925B1 - A method for producing components for hydraulic and / or brake fluids - Google Patents

Abstract

Components for hydraulic and/or brake fluids of the ester type, used in hydraulic systems of mechanisms or brakes of motor vehicles, are produced by esterification of by-products from the production of cyclohexanone. These are a diverse mixture of acids, esters and polyesters, esterified with a monohydric alcohol with a carbon number of Ci to C4 at a temperature of 80 to 300 °C under the catalytic effect of strong mineral acids and/or aromatic sulphonic acids and a pressure of 0.1 to 4.0 MPa. An ester fraction is obtained from the esterification product by distillation under reduced pressure, which is transesterified with a hydroxy compound containing 1 to 4 hydroxyl groups and with a carbon number of 2 to 200 at a temperature of 80 to 250 °C. The unreacted hydroxy compound is separated from the component by distillation after the transesterification is complete.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for producing components for hydraulic and / or brake fluid of the ester type in a technically uncomplicated manner. so far little used by-products from organic production. 238925

In particular, a viscosity index with a temperature range of -40 to 200 ° C and a temperature oxidation stability of at least up to 230 ° C are required today mainly to satisfy the hydraulic fluid. In addition, the liquid must not corrode structural alloys, expand rubber products, "rubber", have sufficient lubricating power, be foamed in the area, and form haze. In addition to other properties, it is also required to be non-flammable and non-toxic.

As the hydraulic and brake fluids, a different mixture of liquids is used which has the aforementioned properties. For the most part today in the world, mixtures of base-alkylene glycols and their higher monoalkyl ethers / NSR publications are used in this world. No. 2,305,918, ZSSRpat. 318,620.

However, glycol ether hydraulic fluids are already beginning to deteriorate because of their hydrophilicity. Moisture, which enters the hydraulic system from the air, causes the brake fluid to boil and thereby deteriorates. Recently, glycol ether brake fluids have been successfully replaced by blends, some of the major components of silicone oil / USSR being 255,470; U.S. Pat. 4,019,997; NSR publik. or esters of boric acid / Franc, U.S. Pat. No. 2,122,540, NSR Publ. No. 2,525,403.

In addition to silicone oils and borates, which are still relatively expensive, mixtures based on esters prepared by esterification of dicarboxylic as well as monocarboxylic acids with monoalkyl glycol ethers are also mentioned.

These fluids do not contain air humidity and meet the strictest quality criteria for brake and hydraulic fluids / V, even after other aspects. Briton. pat. 1,083,324; NSR publik. 2 021 779]. However, the disadvantage of these hydraulic fluids is the relatively high level of multi-stage preparation of the basic esters and hence their cost.

According to the present invention, there is provided a method for producing components for hydraulic and / or brake liquids based on distillation residues from the rectification of the reaction product from the production of cyclohexanol and / or cyclohexanone by catalytic oxidation of cyclohexane, characterized by ester contents in the ester number range of 100 to 500 mg KOH.g 1 and a hydroxyl content of from 0 to 10% by weight. it is carried out by treating the distillation residue with monohydric alcohols having carbon numbers of C 1 to C 4 in the molecule, or a mixture thereof, preferably with catalytic acicidal mineral acids, preferably sulfuric or trihydrogenphosphoric and / or aromatic acid acids, preferably p-toluenesulfonic acid, naphthalenesulfonic acid, 80 DEG-300 DEG C., the reaction product is distilled off mainly from the reaction water and the unreacted alcohol by distillation under reduced pressure, the fraction having a boiling point of 80 DEG to 140 DEG C., calculated at a pressure of 1.3 kPa, and the fraction thus obtained is re-esterified with hydroxylase. or a mixture of hydroxyl compounds having 1 to 4 hydroxyl groups per molecule and having carbon numbers of C 4 to C 18, preferably under catalytic agitation of a known esterification catalyst, at a temperature of 80 to 250 ° C, wherein the resulting reduction of the compound is continuously distilled from the reaction mixture and after at the end The reaction is carried out by distillation of the unreacted hydroxy compound or the mixture of hydroxy-compounds. An advantage of the method of manufacturing the components for hydraulic and / or brake fluids of the present invention is technical simplicity, and conventional esterification equipment can be utilized for production.

Another advantage of very good technical parameters of the components. A higher boiling point of 3 238925 reverts to a world-class top-quality product of this kind. Last but not least, the advantage is the high technical and economic recovery of the by-products from the production of cyclohexanone and cyclohexanol, which, with a low-value by-product, is only used as fuel.

The raw material for the production of components for hydraulic and / or brake fluids according to the invention is by-products, generally isolated as a distillation residue from distillation, respectively. rectification from the production of cyclohexanone, generally by catalytic oxidation of cyclohexane.

It consists predominantly of a mixture of monocarboxylic and dicarboxylic acids, hydroxycarboxylic acids and keto acids, esters, polyesters of said acids and cyclohexanol. The present ester esters - lactones present in monomeric form, but also as dimers and above. The approximate total monocarboxylic acid (acid: butyric, caproic, valeric, enantiomeric, etc.) is 23 wt%, hydroxyacids / gamma-hydroxybutyric acid, delta-hydroxyvaleric, epsilon-hydroxycaproic acid and others (about 17 wt%).

The epsilon-ketoenantic acid content of about 15 wt. % dicarboxylic acids / succinic, glutaric, adipic / about 10 wt. cyclohexyl esters / cyclohexyl esters, cyclohexane caprate, dicyclohexyl glutarate, cyclohexyl adipate, and other (about 7%), hydroxyl butyric acid lactones / lactone, hydroxycaproic, hydroxy valeric (about 3%) by weight.

In addition, water (4 to 8% by weight) is usually dissolved and admixtures of elements of the elements (Co, Fe, Ni, Ti, Zn, Cu, Hg, Ca) are esterified by distillation of the monovalent alcohol with carbon numbers of 1 to 4. It may be methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol and isobutanol. Mixtures of these alcohols may also be applied. The second step of esterification - the transesterification of the fraction containing predominantly lower alkyl esters of monocarboxylic and dicarboxylic acids can be carried out with monovalent or polyhydric alcohols having carbon numbers of 2 to 200, such as butanol, isooctanol, ethylene glycol, diethylene glycol, 2-ethylhexanol, propylene glycol, pentaerythritol, glycerol, trimethylolpropane, polyethylene glycols, polypropylene glycols. It may also be esterified to a different degree by ethoxylated or propoxylated alcohols C1 to C2. The most appropriate zldčeninám for transesterifying glycol monoalkyl ethers include propylene glycol etylénglykolua which Majd one of the free -OH group, such as ,: monomethyl ether, diethylene glycol monomethyl ether, triethyleneglycolmonomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, trietylénglykolmonoetyléter, ethylene glycol monobutyl ether, diethylene glvkolmonobutyléter, trietyléňglykolmonobutyléter, propylénglykolmonoetyléter and dipropylene glvkolmonoetyléter.

The esterification according to the invention is carried out in two stages by lowering the lower aliphatic alcohol Cický-C ^ v in the first stage in excess of the carboxylic and alkyl ester groups in the distillation residues from the cyclohexanone production at normal or elevated pressure at 80 to 300 ° C.

Upon completion of the reaction, unreacted alcohol is separated from the reaction product by known procedures with reaction water, and the ester formed is separated. When the first-degree esterification is carried out by a continuous process in the esterification column, then the reaction water phase with the unreacted excess alcohol is exited mostly by the column head and formed by the bottom of the column.

The ester fraction in the second stage is re-esterified with a compound containing one or more hydroxyl groups, most preferably a glycol ether of molecular weight 76 to

238925 4 210 at a temperature of 120 to 250 UC, usually by blowing the reaction flask with an inert gas and nitrogen, argon or carbon dioxide. An esterification or transesterification catalyst can be used to accelerate the first and second degree esterification, which can be a strong mineral acid (sulfuric acid, trihydrogenphosphoric acid), further organic sulfo acids (benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid).

To carry out the process according to the invention, ion exchangers, anhydrides and acid acyl halides, boron, zinc, magnesium compounds can be used as esterification catalysts. Especially suitable as catalysts for the efficiency and quality of the product are the esterification, esterification, or polyesterification of the lithium compound (e.g. lithium hydroxide, titanium (e.g. tetrabutyl titanate / phosphorus (e.g. sodium hypophosphite, which at the same time prevents the dark product /, tin, antimony, germanium, uranium, cobalt, manganese and molybdenum.

During the transesterification, the lower alcohol C 1 to C 4 liberated from the reaction mixture used for esterification in the first stage is separated from the reaction mixture. This is most often provided by esterification of the distillation residues from the production of cyclohexanol and cyclohexanone.

Upon completion of the pre-esterification and / or polyesterification, unreacted alcohol is separated from the reaction product by distillation, which is typically also recycled.

The production method according to the invention is carried out discontinuously, but can also be carried out semi-continuously or continuously. It is possible to carry out the first stage of esterification continuously and the second stage of transesterification be discontinuous or opposite.

The components of the hydraulic and / or brake fluid produced according to the present invention can be used to transfer power in hydraulic systems either alone or more often in other liquids and additives. improve the desired properties.

Further details, as well as the advantages of the method of manufacture of the present invention, are exemplified. Přikladl

1000 g of methanol and 1300 g of other products - dark brown distillation residues from the production of cyclohexanone and cyclohexanol by cyclohexane oxidation with such a characteristic were weighed into a 5 dm 2 rotary autoclave: acid number = 269.2 mg KOH / g} saponification number = 416.2 mg KOH / g; bromine number = 20.9 g B B / 100 g; OH = 5.7% by weight} water 4.6% by weight,: density at 20 ° C = 1,137 kgm dynamic viscosity at 20 ° C · 268.7 mPa.s.

The autoclave is heated to a reaction temperature of 220 ° C and the mixture reacts for two hours at a pressure of 5.7 MPa. Upon completion of the first stage esterification, the reaction product obtained is subjected to distillation at atmospheric pressure to remove unreacted methanol and reaction water.

Subsequently, the fraction having a boiling point of 80 to 140 ° C / 1.3 kPa was distilled off under reduced pressure (620 g), containing predominantly the methyl esters of monocarboxylic and dicarboxylic acids. The fraction has the following properties: acid value 7.64 mg KOH / g} saponification number > 459.7 mg KOH / g} OH 5.6% wt. 3

To a 3 dm esterification flask was weighed 400 g of the ester fraction obtained in first-stage esterification, 450 g of ethylene glycol monobutyl ether, 17 g of tetrabutyl titanate and 1.5 g of sodium hypophosphite.

With stirring, the mixture is allowed to react for 10 hours at 90-145 ° C while blowing off the reaction mixture with nitrogen. During the reaction, 288 g of a methanol-ethylene glycol monobutyl ether mixture was distilled off from the esterification flask continuously. At the end of the reaction, 78 g of unreacted ethylene glycol monobutyl ether and other volatile components were distilled off under reduced pressure (2.4 kPa) from the reaction product. 442 g of oily product are obtained as a component for both brake and hydraulic fluid with the following characteristics:

Boiling point determined by standard SAE HARRINGTON C. I .: Seifen-Ole-Pette-Wachse 104, No 14, 396/1978 /: 283 ° C

Kinematic viscosity at -40 ° C »2 843 mm 2 s-1 at 50 ° C 10.4 mm 2 s-1 and at 90 ° C = 4.0 mm 2 s \ t

Pour point: <-60 ° C. EXAMPLE 2 400 g of the ester fraction from the first stage esterification obtained as in Example 1.450 g of triethylene glycol monoethyl ether, 1.7 g of sodium hypophosphite and 2.0 g of p-toluenesulfonic acid were reacted in an esterification flask at 90-200 DEG C. for 18 hours.

124 g of methanol are separated from the reaction medium during the re-esterification reaction.

After vacuum distillation, 340 g of unreacted triethylene glycol monoethyl ether remain in the flask with 361 g of product with the following properties:

Boiling point c 265 ° C>

Kinematic viscosity at -40 ° C = 1521 mm 2.s-1 at 50 ° C »5.8 mm 2 s 1 at 90 ° C 2.4 mm 2 s

Pour point i <-60 ° C. Example 3

39.0 g of a mixture consisting of oxidation residues - methanol in a weight ratio of 2: 1 together with p-toluenesulfonic acid in an amount of 0.25% by weight are fed to the column esterifier. for the mixture. The reaction zone is maintained at a temperature of 110 ° C, the residence time of the reaction mixture is 6 hours. The reaction water, together with the excess methanol, continuously leaves the top of the esterification reactor. The product flows from the bottom of the reactor and collects in the bank. The ester product is distilled off from the reaction product discontinuously under reduced pressure (1.3 kPa / ester fraction) at 80-140 ° C. Thereafter, 415 g of the thus obtained fraction were esterified with 490 g of diethylene glycol monoethyl ether in the presence of 1.9 g of tetrabutyl titanate.

The reaction mixture was purged with nitrogen for 12 hours at 90-145 ° C. 292 g of a methanol-diethylene glycol monoethyl ether mixture was continuously distilled from the esterification flask during the reaction.

At the end of the reaction, 81 g of unreacted diethylene glycol monoethyl ether and other volatile components were distilled off under reduced pressure (2.2 kPa) from the reaction product. 451 g of an oil-yellow product are obtained as a component for hydraulic or brake fluid with the following characteristics:

Boiling point 270 ° C; kinematic viscosity at - 40 QC 2 520 mm2.s at 50 ° C 8.8 mm2.s * a at 90 ° C »3.2 mm2.s-1} temperature, solidification: <-60 ° C .

Claims (2)

238925 6 SUBJECT OBJECTS A method for producing components for hydraulic and / or brake fluids based on distillation residues from the rectification of the reaction product from the production of cyclohexanol and / or cyclohexane by catalytic oxidation of cyclohexane, characterized by the ester content of the ester number range of 100 to 500 mq KOH.g -1 and a hydroxyl group content of from 0 to 10% by weight, wherein the distillation residue is treated with a monohydric alcohol with a carbon-metal number C | up to C4 in the molecule, or mixtures thereof, preferably under the catalytic action of strong mineral acids, preferably sulfuric or trihydrogenphosphoric and / or aromatic sulfoacids, preferably p-toluenesulfonic acid naphthalenesulfonic acid at 80 to 300 ° C separating from the reaction product, after distillation of the reaction water and unreacted alcohol, a fraction having a boiling point of 80 DEG-140 DEG C., distilled under a pressure of 1.3 kPa and distilling the fraction thus obtained by re-esterification with a hydroxy compound or a hydroxyl compound with 1 to 4 hydroxyl groups in a molecule and with a carbon number of C 1 to C 18, preferably under the catalytic effect of an esterification catalyst, at a temperature of 80 to 250 ° C, wherein the flash-lowering compounds are continuously distilled off the reaction mixture and, upon completion of the reaction, the unreacted hydroxy compound or hydroxy compound mixture is separated from the product distillation . 2. A method for producing components for hydraulic and / or brake fluids according to claim 1, wherein at least one monoalkyl ether of ethylene glycol and / or propylene glycol, preferably ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoethyl ether, is used as the hydroxy ester for transesterification. , diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monoethyl ether and dipropylene glycol monoethyl ether.