DK150186B - ORTHOSILIC TESTS USED AS HYDRAULIC FLUID OR COMPONENT THEREOF AND HYDRAULIC FLUID - Google Patents

Description

150186

The invention relates to one orthosilicate ester for use as a hydraulic fluid or as a component therein, and one hydraulic fluid.

Hydraulic fluids are usually used in hydraulic systems that perform various functions, and the combination of properties required by the fluid varies from case to case.

One of the most serious requirements is related to car brake and clutch fluids. Manufacturers of vehicles and authorities related to this technical area set very strict specifications for such fluids, requiring a very high standard in numerous properties.

2 150186 In recent times, a growing trend has emerged in the design of vehicles for the use of a single hydraulic system to operate the equipment, such as power steering, shock absorption means and brakes, which have hitherto been provided with separate hydraulic systems. This has created serious problems with the composition of suitable fluids. The mineral oil-based fluids used to date in power control and shock absorption systems are satisfactory in terms of a nitrile and chloro-rubber rubber used for the seals and gaskets in such systems, but are highly detrimental to the natural rubber species and the synthetic rubber used for the construction of hydraulic braking systems and clutch systems. This results in excessive swelling of the last-mentioned seals, which can lead to a seriously failing function of the brake or clutch system. Conversely, the fluids previously used in brake and clutch systems, which are normally based on glycols, glycol ethers and / or glycol ether systems, and which have worked satisfactorily in such systems have a detrimental effect on the nitrile and chloroprene rubber gaskets used. in power control systems and shock absorption means, which can also lead to malfunctioning. In the case of operation of the vehicle, the importance of reliability during operation, which is generally desirable by all mechanical bodies, is increased to an absolutely essential requirement due to safety considerations. Therefore, a need has arisen for a fluid which can be used satisfactorily in a central system which controls the operation of a number of different parts of an equipment.

Among the many different types of fluids that have been proposed as basic materials for hydraulic fluids, there are certain orthosilicate esters. These have been proposed, and in some cases used, for certain categories of hydraulic fluids where hydrolytic stability is of relatively little importance. However, such esters have always been discarded by manufacturers for liquids to be used in cars because of their totally unacceptable hydrolytic stability for such purposes.

It is an object of the invention to provide an orthosilicate ester of the kind set forth in the preamble of claim 1 which has superior hydrolytic stability and soil due to a balanced combination of boiling point, hydrolytic stability and rubber swelling properties suitable for hydraulic fluid formulation. , as well. a hydraulic fluid.

The orthosilicate ester of the invention is characterized by the method of claim 1. Surprisingly, it has been found that the new orthosilicate esters have superior hydrolytic stability and that due to balance of required properties such as boiling point, hydrolytic stability and rubber source properties, they are suitable for use in the formulation of hydraulic fluids for automotive equipment, including liquids for central systems . These orthosilicate esters are characterized by the presence of at least one glycol monoether residue and at least one tertiary alkyl group.

The hydraulic fluid according to the invention is characterized by the characterizing part of claim 5.

The term Mtertiary alkyl group "in the present context means an alkyl group containing a tertiary carbon atom, i.e., a carbon atom on which no hydrogen atom is substituted.

The glycol monoalkyl ether residue present in the orthosilicate esters of the invention is derived from monoalkyl ethers of glycols which may be mono-, di- or poly-glycols and such monoalkyl ethers may be represented by the formula: R5 R6

I I

H - O-CH-CH-O - R

n 4 wherein each of the radicals R and R is a hydrogen atom or a g g methyl group, provided that R and R are not both methyl groups, where R is an alkyl group containing between 1 and 8 carbon atoms and where n is an integer. The residues of such glycol monoalkyl ethers can thus be represented by the formula: f R5 R6 Ϊ

I I

--CH - CH - 0 - R

n

It is preferred that R contains between 1 and 4 carbon atoms, preferably 1 or 2 carbon atoms. The integer n is 1 in the case of a monoglycol monoether, 2 in the case of a di-glycol monoether and 3 or more in the case of a poly-glycol monoether. In general, the larger the molecule of the orthosilicate ester, the higher the boiling point, and the content of carbon atoms of the orthosilicate ester molecule is an appropriate measure of its size. Accordingly, a minimum content of carbon atoms of 15 is required to provide a compound of sufficiently high boiling point, and such content will depend, inter alia, on the whole number n. It is therefore preferred that n be at least 2 and it may be as high as 20, but preferably not above 6. In general, n preferably has a value between 2 and 4. However, it should be understood that e.g. it is also possible that n may be 1 in some glycol monoether residues and this is offset by n being much larger in other residues. As previously stated, the total carbon content is an appropriate indicator of the size of the molecule, i.e. the cumulative effect of the value of each integer n plus the size of the above alkyl groups constituting R 2, R 2, and / or R 2, and the total content of carbon atoms will normally be in the range of 15 to 120, especially between 15 and 60.

As previously indicated, R 1 may, as an alternative, be a tertiary alkyl group, and in this case R 1 preferably contains between 4,5 and 10, especially between 4 and 8, carbon atoms. As also stated in the foregoing, any of the radicals R, R or R may be a tertiary alkyl group. In this case, such alkyl groups also preferably contain between 4 and 10 carbon atoms, preferably between 4 and 8 carbon atoms. However, at least one of the groups 12, 5 4 R, R, R and R must be a glycol monoalkyl ether residue of the type defined before, and preferably at least two of the groups R, R, R 4 and R are glycol monoether residues.

Accordingly, in the two most preferred embodiments of the invention, orthosilicate esters having the general formula: R70 OR8 R11 ^ OR12 \ / \ / are provided.

Si or Si / \ / \ R100 OR9 R ^ O OR13 (A) (B) In the case of formula (A): 7 8 9 10 (i) At least one and at most three of the radicals R, R, R and R are one propylene glycol monoalkyl ether residue of the formula: s \ R5 R6 I i

- CH-CH-0 - R

p. 'n 6 wherein: (6) in each pair of adjacent radicals R and R one of these radicals is a hydrogen atom and the other is a methyl group; (f) each n is the same or varies among themselves, and the total value of all integers n is between 8 and 16, especially where each n is between 2 and 4; and (c) each R is the same or varies mutually and is a methyl or ethyl group.

In the case of orthosilicate esters of the above formula (b), (i) R 11 is a tertiary alkyl group containing 4 to 8 carbon atoms, especially a tertiary butyl group; (ii) R is a glycol monoalkyl ether residue of the formula: 'V R6

I I

--CH-CH-0 - R

n s n (iii) is the same as or different from R 12 and is a glycol monoalkyl ether residue of formula R 5 R 6

I I

- CH-CH-0 - R

* A 1 (iv) R 1 is a tertiary alkyl group containing 4 to 8 carbon atoms, especially a tertiary butyl group, and R 1 is the same as or different from R 7 70186 or R 1 is a glycol monoalkyl ether residue having the formula: / \ ff

--CH-CH-0 -—R

And is the same as either R or R or is different from both R 1 and R 2; and (v) in glycol monoalkyl ether residues of the formula: R 5 R 6 I 1

- —CH-CH-0 - R

(a) each of the radicals R 1 and R 2 is the same or different from each other, and both are hydrogen atoms or in each adjacent pair of R 6 and R one of the radicals is a hydrogen atom and the other is a methyl group; (b) each n assumes the same or different values and the total value of all integers n is between 4 and 8 when R is a branched alkyl group, or between 6 and 12 when R is a glycol monoalkyl ether residue with particular preference for each n to be between 2 and 4; and (c) each R is of the same or different values and is a methyl or ethyl group.

The orthosilicate esters of the invention are useful hydraulic fluid components and for this purpose they can be used as starting materials. In this case, the orthosilicate tests will comprise the entire amount, or substantially the entire amount of the hydraulic fluid, e.g. 70 or 99% by weight. When used in this way, the orthosilicate tests can, if desired, mix them with small amounts of other known starting materials.

However, the orthosilicate tests are particularly useful for admixture with substantial amounts of other known starting materials in order to modify the properties of the latter or to provide a liquid with a mixture combination of the properties of the separate components. In this case, orthosilicaterae may be present in a wide range of ratios, e.g. from 1 to 70% by weight, but especially between 10 and 60% by weight. In this way, for example, formulate fluids for central systems that largely combine the good rubber source properties associated with nitrile rubber of the orthosilicate systems and the good rubber source properties associated with natural rubber and synthetic rubber types commonly used in automotive brake and coupling systems for known synthetic starting materials - and switching systems.

Among the starting materials with which the orthosilicate tests of the invention can be mixed are the known and widely used glycols, polyoxyalkylene glycols and mono- and di-alkyl esters thereof. Such materials are commercially available, e.g. under the registered trademark "Ucon". Other examples of these materials are those obtainable under the trademarks "Oxitol" and "Cello-solve." Other starting materials are borate ester from English Patent No. 1,341,901. Other examples of known starting materials which can be mixed with the orthosilicate systems of the invention are those di-carboxylic acid esters and glycol diesters referred to in English Patent No. 1,341,901 and more fully disclosed in English Patent Nos. 1,083,324 and 1,249,803, respectively.

Embodiments of the invention include hydraulic fluids containing at least 70% of an orthosilicate ester of the invention, or a mixture of such esters, or a mixture of one or more orthosilicate esters of the invention with one or more known starting materials for hydraulic fluids.

9 150186

It is highly desirable that the hydraulic fluids of the invention have a kinematic viscosity at -40 ° C of not more than 5,000 cSt, especially not above 2,000 cSt, and a boiling point of at least 250 ° C, especially at least 260 ° C.

During use, the hydraulic fluids of the invention will usually be mixed with small amounts of various additives of the type normally used in hydraulic fluids.

Typical additives which can be used according to the invention are lubricating additives selected from the group comprising castor oil or castor oil treated in various ways, e.g.

Castor oil derived from the first extrusion of castor seeds.

Castor oil according to specification DTD 72.

Blown castor oil, i.e. castor oil blown with air or oxygen while heating.

Special, pale, blown castor oil, i.e. a similar blown castor oil.

"Hydricin 4", i.e. a commercially available castor oil treated with ethylene oxide / propylene oxide.

Other lubricating additives which can be incorporated into hydraulic fluids of the invention include borate esters, e.g. tricresylborate and phosphorus esters, especially phosphates, e.g. tricresyl phosphate.

The hydraulic fluids of the invention may also comprise smaller proportions of polyoxyalkylene glycols or ethers thereof, e.g. those sold by Union Carbide Corporation under the registered trademark "Ucon", especially those belonging to the LB and HB series. Suitable examples of these polyoxyalkylene glycols and their ethers and esters are set forth in English Patent No. 1,055,641. Other suitable lubricants are orthophosphate or sulfate salts of primary or secondary aliphatic amines having a total of between 4 and 24 carbon atoms, dialkyl citrates having an average of between 3.5 and 13 carbon atoms in the alkyl groups, aliphatic dicarboxylic acids and esters thereof, with specific examples. are: diamylamine orthophosphate dinonylamine orthopho sphat diamylamine sulfate dinonyl citrate di (2-ethylhexyl) citrate polyoxyethylene sebacate derived from a polyoxyethylene glyeol of molecular weight 200 polyoxyethylene azelate derived from a polyoxyethylene glycol ethylene polyethylene polyethylene / polyoxypropylene glutarate derived from mixed polyoxyglycols with average molecular weight of approx. 200 glutaric acid azelaic acid sebacic acid succinic acid diethylsebacate di-2-ethyl-hexyl-sebacate di-isoethyl ethyl azate 11 IS0186

Saturated aliphatic acids or salts thereof may also be used, e.g. oleic acid or potassium ricinoleate.

Corrosion inhibitors which can be used according to the invention can be selected from heterocyclic nitrogen-containing compounds, e.g. benzotriazole and benzotriazole derivatives, such as those described in English Patent No. 1,061,904, or mercapto-benzothiazole. Many amines or derivatives thereof are also useful as corrosion inhibitors, for example di-n-butylamine di-n-amylamine cyclohexylamine morpholine triethanolamine and soluble salts thereof, e.g. cyclohexylamine carbonate.

Phosphites are also good corrosion inhibitors, e.g.

tri-phenyl-phosphite di-isopropyl-phosphite and certain inorganic salts can be incorporated, e.g. sodium nitrate.

Other additives which can be incorporated are antioxidants such as diarylamines, e.g. diphenylamine, p, p'-dioctyl-diphenylamine, phenyl-t 2 -naphthylamine or phenyl- / o-naphthylamine. Other suitable antioxidants are those commonly known as inhibited phenols which can be exemplified by 2,4-dimethyl-6-t-butyl-phenol 2,6-di-t-butyl-4-methyl-phenol 12 2, β-di-t-butyl-phenol 1,1-bis- (3,5-di-t-butyl-4-hydroxyphenyl) -methane 3,3 ', 5,5 *, - tetra-t-butyl -4-41-dihydroxy-diphenyl-3-methyl-4,6-di-t-butyl-phenol-4-methyl-2-t-butyl-phenol

Among other additives which may be used are listed phenothiazine and its derivatives, e.g. those having alkyl or aryl groups attached to the nitrogen atom or to the aryl groups of the molecule,

Other additives which may be used include alkylene oxide / ammonia condensation products as a corrosion inhibitor, for example propylene oxide / ammonia condensation product, disclosed in English Patent No. 1,249,803 »Other lubricating additives which may be used are complex esters , such as those sold under the trademark "Reoplex 641" and also disclosed in British Patent No. 1,249,803. In addition, long-chain corrosion inhibitors (e.g.

C10-18 ^ of Ρθη Pri aiflin ° 9 polymerized antioxidants in the form of a quinoline resin, as disclosed in British Patent No. 1,249,803, examples of such amines and resins being the commercially available materials Armeen 12D and Agerite resin D.

Conventional additives such as those described above are usually used in small amounts such as 0.05 / 4 to 1054, e.g. 0.154 to 254, by weight.

The orthosilicate esters of the invention can be prepared using the technique conventionally used in the preparation of such esters, examples of which are the reaction of a silicon tetrahalide such as SiCl 2 with four parts of a hydroxy compound such as glycol monoether or alkanol or the transesterification of a tetra- (hydrocarbyl) silicate having the appropriate amounts of a hydroxy compound. In order to prepare an orthosilicate ester containing four identical glycol monoether residues, silicon tetrahalide can be e.g. reacting with a glycol monoether in a molar ratio of 1: 4 or a tetra- (hydrocarbyl) silicate can be transesterified with a glycol monoether in a molar ratio of 1: 4, but preferably this reaction or transesterification is carried out in the presence of an excess of glycol monoether, eg. in an excess of 10% in the case of reaction with SiCl 2 or a larger excess in the case of a transesterification reaction.

To prepare an orthosilicate ester containing 2 residues of a glycol monoether plus 2 residues of a different glycol monoether therefrom, a sequencing method, i.e. reaction with SiCl 2 in a molar ratio of 2: 1 or a transesterification in a molar ratio of 2: 1 followed by further reaction or transesterification with a different glycol monoether in a molar ratio of 2: 1. Thus, the nature of the glycol monoether residues is determined by selection of the glycol monoether used and the number of each species of the residue is determined by the molar ratio used. Examples of suitable tetra- (hydrocarbyl) silicates are tetramethylsilicate, tetraphenylsilicate and tetraethylsilicate, the latter being preferred. Other suitable tetra- (hydrocarbyl) silicates are described in English Patent No. 1,075,236.

In the case of orthosilicate esters containing one or more alkyl groups in place of glycol monoether residues, the same preparative technique may be used, except that part of the glycol mono ether is replaced by the appropriate alkanol. In this case, it is preferred to introduce the alkyl group before the glycol monoether residues, e.g. by reaction between SiCl 2 and an alkanol, such as t-butanol, in the amount required to provide the desired number of alkyl groups, followed by reaction with glycol monoether. When preparing orthosilicate esters containing alkyl groups by transesterification, a suitable tetra (alkyl) silicate, e.g. tetra (t-butyl) silicate containing the desired alkyl group or alkyl groups is reacted with a glycol monoether at a molar ratio of 1: 1, 1: 2 or 1: 3 to introduce 1, 2 or 3 glycol monoether, respectively. chars. Alternatively, and preferably, a tetra (hydrocarbyl) silicate, such as tetraethyl silicate, can be transesterified with an appropriate alcohol to introduce the desired number of the required alkyl groups and the compound thus formed can be transesterified with a glycol mono ether to replace the residual ethyl groups with glycol monoether residues.

When the preparation of the ortho silicates is done by transesterification, the tetra (hydrocarbyl) silicate starting material and the reaction conditions can be selected such that released hydroxy compounds can be removed from the reaction mixture by distillation. P.eks. gives transesterification of tetraethyl silicate with glycol monoether to the formation of ethanol and tetra (glycol monoether) orthosilicate. The relatively low-boiling ethanol can be distilled off so that the transesterification, which is an equilibrium reaction, can end.

In a preferred process for preparing the novel ortho-silicate esters by the transesterification route, a catalyst, e.g. metallic sodium which promotes the reaction via formation of the alkoxide of the glycol monoether, or known transesterification catalysts such as p-toluene sulfonic acid or a tetraalkyl titanate, e.g. tetraisopropyl titanate.

Preparation of the orthosilicate esters of the invention from a silicon tetrahalide can be readily accomplished by reaction of the appropriate hydroxy compound with the tetrahalide at a temperature of between -40 ° C and 150 ° C, preferably between 40 and 100 ° C. If desired, this reaction can be carried out in the presence of an inert solvent such as alkyl ethers, toluene, petroleum ether, etc. In addition, an acid acceptor, such as a tertiary amine, can be used to neutralize hydrogen halide formed during the reaction.

When the preparation is carried out by the transesterification route, the reaction temperature used may e.g. may be 80 to 250 ° C, preferably 120 to 200 ° C, and ebb inert solvent may also be used if desired. Further details of the manner in which the glycol monoether orthosilicates can be prepared are given in Journal of Inorganic Nuclear Chemistry, 1968, Vol. 30, pages 721 to 727.

150186 15

The invention will now be illustrated with reference to the following examples: EXAMPLE 1

Preparation of tris (triethylene glycol monomethyl ether) t-butyl silicate

Quantity

Reactants Molecular weight Amount of moles of silicon tetrachloride used 170 170 g 1T0 tert. butanol 74 74 g 1.0 triethylene glycol monomethyl ether 164 492 g 3.0 diethyl ether 600 ml pyridine 85 g

The silicon tetrachloride and diethyl ether were introduced into a 2 liter round bottom, three necked container equipped with a stirrer, a thermometer, a thermocouple, a nitrogen inlet opening, a burette funnel, a reflux condenser and a water column with a fall. The tertiary butanol and the pyridine (the latter used as an acid acceptor to prevent the reaction of tertiary butanol with hydrogen chloride produced in the reaction) were introduced into the burette funnel and slowly added to the vessel at an initial temperature of 20 ° C. The temperature was detected by the thermocouple due to the thermometer being hidden by a white precipitate. The addition of the tertiary butanol was completed over a period of 1.5 hours during which, as a result of the exothermic reaction, the temperature was allowed to rise to a maximum of 35 ° C at the end of the reaction. The reaction mixture was then stirred for an additional 0.5 hours at room temperature and then filtered.

The apparatus was assembled again as before and the filtered reaction mixture was introduced into the vessel. The triethylene glycol was then added to the reaction mixture via the burette funnel, first slowly, resulting in no detectable heat generation, and then the addition rate was increased, resulting in a heat generation of 5 ° C (max). During the addition, nitrogen was blown into a vigorous stream to remove hydrogen chloride.

The crude product was then heated to 70 ° C for a total of 9.5 hours to ensure that the reaction was complete and it was finally distilled at 170 ° C under 0.05 mm Hg pressure to form 140 g. (23.7 wt. # Based on silicon tetrachloride) of a clear brown liquid containing 4.95 # Si by weight (theoretical 4.75 #) and 0.17 wt. # Residual chlorine (theoretical 0 #).

EXAMPLE 2

Preparation of tris (triethylene glycol monomethyl ether) t-butyl silicate

Reactants Molecular weight Quantity used Number of moles

Silicon tetrachloride 170 170 g 1.0

Tertiary butanol 74 74 g lr0

Tri ethylene glycol monomethyl ether 164 542 g 3, -3

Pyridine 79 g 347 g 4.4

Toluene 1800 ml

The silicon tetrachloride and 250 ml of toluene were introduced into a 2 liter round-bottomed, three-necked container equipped with a burette funnel, a stirrer, a reflux condenser, a nitrogen inlet port and a thermocouple. The container was placed on an ice bath and 87 g of pyridine was added to the container over a period of 40 minutes during which time the temperature of the container contents was kept at a value of 15 ° C - 1 ° C. Then the container was removed from the ice bath. and it was kept under stirring for 15 minutes, during which time the temperature thereof was allowed to rise to ambient temperature (about 20 ° C). The tertiary butanol dissolved in 50 ml of toluene was then added to the vessel over a period of 0.5 hours during which the temperature was maintained in the range between 20 ° C and 25 ° C. The contents of the vessel were then heated to 80 °. C for 1.5 hours.

The contents of the container were then poured into a larger (3 liter) container equipped similar to the original reaction vessel and an additional 500 ml of toluene was added.

Then, the remaining amount of pyridine (260 g) was added over a period of 1.5 hours, during which the temperature was maintained in the range between 20 and 25 ° C. The triethylene glycol monomethyl ether was then added slowly to the reaction mixture. Over a period of 0.75 hours, 1/3 of the glycol ether was added, maintaining the temperature in the range between 20 and 35 ° C. At this stage, the contents of the container became too thick for further reaction and the addition was stopped while further added 600 ml of toluene. The addition of the glycol ether was then resumed and the remaining portion was added at a temperature maintained in the range of between 30 and 40 ° C, and finally the addition was completed over a period of a total of 2.5 hours, leaving the remaining amount. of toluene (400 ml) was added after 3/4 of the glocyl ether was added. The reaction mixture was then kept under stirring at 90 to 100 ° C for 2.5 hours, and then an additional 7 hours at 80 ° C. Finally, the crude product was filtered using a diatomaceous earth filter aid, distilled on a rotary evaporator and finally distilled at a temperature of 170 ° C under a pressure of 0.4 to 0.5 mm Hg to give 236 g (40 wt. (calculated relative to the silicon tetrachloride) of a deep yellow liquid containing 4.86% Si by weight (theoretical 4.75%) and 0.05% by weight of residual chlorine (theoretical 0%) * EXAMPLE 3

Tris (tripropvlénglvcolmonomethvlether) -neopentvlsilicat

reactants

Silicon tetrachloride 174 g

Tripropylene glycol monomethyl ether (commercially available material marketed under the trademark "Dowanol TPM") 679 g

Neopentyl alcohol 88 g

Pyridine 340 g

Toluene 2.5 liters 18

The toluene and silica gel tetrachloride were mixed in a 5 liter container and a mixture of the neopentyla alcohol and 79 g of pyridine was added under cooling, under which the reaction temperature reached a maximum of 42 ° C due to the exothermic reaction taking place · The reaction mixture was heated to 100 ° C for 4 hours and then allowed to cool overnight. Then the tripropylene glycol monomethyl ether and the remaining portion of the pyridine were added over a period of 0.5 hours, during which time the resulting heat generation was controlled by cooling (water bath). The reaction mixture was then heated to 112-114 ° C for 5 hours and 20 hours. minutes and cooled and the precipitated pyridine hydrochloride was filtered off. The solvent was then distilled off on a rotary evaporator and the product was finally distilled under high vacuum (200 ° C / 0.1 mm Hg) to give 484.4 g (66.3%) of the final product.

Analysis: 3.74% Si (theoretical 3.84%); residual chlorine 0.15%.

EXAMPLE 4

Tri s- (tri ethylene glycol monomethyl ether) t-butyl silicate

reactants

SiCl4 170 g t-butanol 74 g triethylene glycol monomethyl ether 542 g pyridine 347 g toluene 2.5 liters + 250 ml

SiCl4 and toluene (2r5 liters) were mixed and a mixture of the t-butanol and 87 g of pyridine was added thereto, during which time the temperature was kept below 50 ° C. The reaction mixture was then heated to 100 ° C for 4 hours and The mixture was cooled and then a mixture of the triethylene glycol monomethyl ether and the remaining portion of the pyridine was added (during which time the temperature was kept below 50 ° C). An additional amount of toluene (250 ml) was added to facilitate stirring and then the reaction mixture was heated to 100 ° C for a total of 4 hours, cooled and filtered, and the toluene was distilled off (100 ° C / 20 19 torr.). The resulting product was then distilled under high vacuum (210 ° C / 0.5 mm Hg) to give 346 g (70.4 $) of the final product.

Analysis: $ 4.92 Si (theoretical 5/68 $); residual chlorine $ 0.04.

EXAMPLE 5

Bis (dipropylene glycol monomethyl ether) -bis (t-butyl) silicate

reactants

SiCl4 170 g

Dipropylene glycol monomethyl ether (commercially available material marketed under the trademark "Dowanol DFMM) 326 g t-butanol 148 g

Pyridine 348 g

Toluene 2.5 liters

The SiCl 4 and the toluene were mixed and then a mixture of the t-butanol and 174 g of pyridine over a period of 2 hours was added to this mixture, during which time a heat generation was controlled so that the temperature of the reactants did not exceed 41 °. C. The reaction mixture was heated to 100 ° C for 4 hours, allowed to cool, then a mixture of dipropylene glycol monomethyl ether and the remaining portion of the pyridine was added. The resulting mixture was heated to 100 ° C for 4 hours, cooled and filtered, and toluene was distilled off, re-filtered, and finally distilled under high vacuum (180 ° C / 0.01 mm Hg) to give 248r2 g ($ 53) of the final product as a clear, yellow liquid.

Analysis: $ 6.02 Si (theoretical $ 5.98); residual chlorine. 0.36 $.

EXAMPLE 6

Bis (t-butyl) - (dipropylene glycol monomethyl ether) - (tri ethylene glycol monomethyl ether) silicate

reactants

SiCl4 170 g t-butanol 148 g

Dipropylene glycol monomethyl ether ("Dowanol DPM") 148 g

Triethylene glycol monomethyl ether 197 g

Toluene 2.5 liters

Firidin 332 g

A mixture of the t-butanol and pyridine (158 g) was added to the toluene and SiCl4, which were previously mixed in a 5 liter vessel (with cooling water bath to keep the temperature below 50 ° C). The reactants were then heated to between 80 and 100 ° for 4 hours, allowed to cool, and a mixture of the dipropylene glycol monomethyl ether and pyridine (79 g) was added thereto (very low heat generation). The reaction mixture was then heated to 80 ° C for 4 hours, allowed to cool, and a mixture of triethylene glycol monomethyl ether and the remaining amount of pyridine (95 g) was added thereto (with cooling water bath). Then, the reaction mixture was heated to 100-104 ° C for 6 hours, allowed to cool, filtered, toluene distilled off and distilled under high vacuum (180 ° C / 0.05 mm Hg). The resulting product was filtered to give 413.1 g (86 °) of a clear yellow liquid.

Analysis: 5.85% Si (theoretical 5%); residual chlorine-0.24% Example 7 21 150186

Tri s- (dipropylene glycol monomethyl ether) -t-butyl-silicate

reactants

SiCl4 170 g t-butanol 74 g

Dipropylene glycol monomethyl ether ("Dowanol DPM") 488 g

Pyridine 348 g

Toluene 1 liter + 200 ml + 200 ml + 200 ml + 400 ml + 1 liter

The t-butanol and pyridine (80 g) were mixed and added to a previously prepared mixture of SiCl 2 and toluene (1 liter). During the addition, cooling with a water bath was used to control the resulting heat generation. The reactants were then heated to 80 ° C for 3 hours. The remaining portion of the pyridine and dipropylene glycol monomethyl ether were mixed and then added to the reaction mixture. During this addition, the reaction mixture was viscous and difficult to keep stirring, and additional amounts of toluene (3 x 200 ml and then 1 x 400 ml) were added when needed. The heat development during the addition was controlled by cooling with a water bath. After the addition, the reaction mixture was transferred to a 5 liter vessel using an additional 1 liter of toluene and then heated to 80 ° C for 12 hours. The resulting product was filtered, the solvent was distilled off, and the product was distilled under high vacuum (200 ° C / 0.1 mm Hg), finally the product was refiltered to give 399 g (73.6%) of clear yellow liquid.

Analysis: 5.48% Si (theoretical 5.17%), * residual chlorine, 15%.

EXAMPLE 8 22 150186

Bis (triethylene glycol monomethyl ether) bis (t-butyl} silicate Reactants 170 g t-butanol 148 g triethyl englycol monomethyl ether 361 g pyridine 348 g toluene 2.5 liters + 250 ml

A mixture of the t-butanol and pyridine (174 g) was added to a previously prepared mixture of SiCl 2 and toluene (2.5 liters), keeping the temperature below 50 ° C during the addition. The reaction mixture was heated to 100 ° C for 4 hours and cooled, and a mixture of the triethylene glycol monomethyl ether and the remaining portion of the pyridine was added thereto. A slight heat generation was obtained and the temperature was kept below 50 ° C. The reaction mixture was then heated to 100 ° C for 4 hours, during which time an additional 250 ml of toluene was added to facilitate stirring.

The resulting crude product was cooled and filtered, and the toluene was distilled off, and then distilled under high vacuum to give 323.1 g (64.6%) of the final product as a clear pale yellow liquid.

Analysis: 5.7% Si (theoretical 5.6%); residual chlorine 0.0 + EXAMPLE 9 23 150186

Bis (tripropylene glycol monomethyl ether) -bis- (t-butyl) silicate

reactants

SiCl4 170 g t-butanol 148 g

Tripropylene glycol monomethyl ether ("Dowanol TPM") 453 g

Pyridine 348 g

Toluene 2.5 liters

A mixture of t-butanol and pyridine (174 g) was added to a mixture of SiCl 2 and the toluene, with cooling with a water bath, over a period of 2 hours, during which time the temperature of the reactants rose to 38 ° C (max) of due to a moderate heat generation. The reactants were then heated to 100 ° C for 4 hours and then cooled, and then a mixture of the tripropylene glycol monomethyl ether and the remaining portion of the pyridine was added thereto over a period of 2 hours (during which a slight heat evolution raised the temperature of the reaction mixture to maximum of 30 ° C). The reaction mixture was then heated to 100 ° C for 4 hours, cooled and filtered, solvent was distilled off and the product was finally distilled under high vacuum (180 ° C / 0.1 mm Hg) to give 567.2 g (63% ) of the final product.

Analysis: 4.96% Si (theoretical 4/8%), residual chlorine not determined.

EXAMPLE 10 24 150186

Tris (tripropylenglvcolmonomethylether) -t-butyl-p! Silicate

reactants

SiCl4 119 g t-butanol 51.8 g

Tripropylene glycol monomethyl ether ("Dowanol TPM") 474 g

Pyridine 237 g

Toluene 250 ml + 300 ml + 600 ml + 200 ml

A mixture of the t-butanol and 80 g of pyridine was added to a mixture of SiCl4 and toluene (250 ml) in a vessel provided with a water bath for cooling. The resulting heat generation raised the temperature to 30 ° C. An additional 300 ml of toluene was added to maintain the flowability and the reaction mixture was then refluxed for 2 hours. The reaction mixture was then cooled and the mixture of the tripropylene glycol monomethyl ether and the remaining portion of the pyridine was added over a period of 1 hour during which time a slight heat generation was observed.

An additional 600 ml of toluene was also added. The reaction mixture was heated to 90 ° C for 10 hours after transfer to a larger vessel using an additional 200 ml of toluene. The crude product was worked up by filtration, distilled off the solvent on a rotary evaporator and finally by distillation under high vacuum (180 ° C / 0.1 mm Hg) to give 380 g (75.9%) of. the final product as a pale yellow liquid.

Analysis: 3.86% Si (theoretical 3.91 / é); residual chlorine 0.76? Ο.

25 IS0186

Infrared spectra of the products of all the preceding Examples 1 to 10 corresponded to the expected product appearing in each case.

The suitability of the orthosilicate esters of the invention for use in hydraulic fluids was demonstrated by measuring the reflux point, the hydrolytic stability and the rubber swelling effect of various esters. The reflux point was measured in the manner specified in the SAE J1703c specification.

Rubber swelling was measured by placing a rubber square (with dimensions of about 2.54 cm x 2.54 cm x 0 ^ 254 cm) in a 56 (8 cm 2) bottle fitted with a layer of glass balls on the bottom. The flask was then filled with the test liquid and placed in a furnace for 3 days at constant temperature, after which the rubber square was removed, washed with ethanol and dried. In this way, squares of styrene-butadiene rubber were used at 120 ° C and squares of natural rubber, which were more temperature sensitive, at 70 ° C, these temperatures being the usual temperatures at which these tests are performed. also nitrile and chloroprene rubber squares used, and in these cases a temperature of 70 ° C was used, as there is no established practice in this regard, because it has so far not been a normal for nitrile and chloroprene rubber to come into contact with brake fluids, which is why these gums have not been studied in this way.

The hydrolytic stability was measured by placing 1 g of water, 1 g of the orthosilicate ester to be tested and 9 g of a commercially requisitioned hydraulic fluid in the form of a glycol ether starting material in a boiling tube, together with particles to prevent shock boiling. , and by heating the mixture over a bunsen burner until it is boiled, then allowing the contents of the boiling tube to cool.

26 150186 • Η hollow σ »is iA in co m s to» »» »*,» w p tn tn cm in H vo u β cm H m -4- m

-P

ή above to Ο β 3

Xj * H

Η β

PXJ

H

• Η P

1 x 0iR

live in

- g CM m CM H

µ i to in »» »» »o C H» 'm h h ξ- bo ο Ό η o tn cm in in <r to β cd g

Ό >> · Ρ I

ι +> β 3 tn UiA 60 ι

Α W

10 +> Ή 0) μ +> β η η +> tn t n t n <1 · <t <ι- o h a h O Ο d cd β >> -P co W t a Mi

H

s t a · § 2 3 o ox

^ ft o Ox W M M tt O

a> o cm tn 60 ^! §

P I -P

-P cO H cd

cd o ι o i o -P

ro ι · η o ι p β h cd P OH OH β ^> x <DH I o

Cd β Η fi H O IH Η Η H OH

O OH OCO S Oi >> 60> »Μ βΗ

H SCO g I Η β-P βΛΙ OH

H Hl HH O Od O -P ^ S M

H OH O >> O S fit Η 0) β Η I

CO O >> O -P> »+> Hl} SH 0) OH

O >> +>> »β HCd O -P ft β .β pi> * A H3 HO 60 0 O'— O -P -P >> · Ρ • P 60.0 60 ft βΗ>, 1 In '- <1 > H 3 β β I βΟ OH HW fV „H Mfl

O OH O O HH 60H Η β> »β I

H I Ηβ>, tQ β, Ο XJ Ο, β O-P

-P> T *> »I ft I O I -P Η I

60 Λ β ft '"' O '- * H'" '' "'' • PO> 0 13 -P ω Οβ ββ >> β ΗΟθ ft β CO Ο .β βΟ ftO ftO>» H Ο Ο Φ β η -µ ft £ Hi oi -p >> β h

ο β ο h -p β-ρ β-ρ S A g ft-P

Xf -PH βΟ -PO ftO-P P4> a Η O

β w -PH WH Η H ¢ 0 I Ο Η Ό H

* 3 10Λ - >> Cd>, Ό >> O -P a O ^ H + »to Λ β A '-'A H> -OO 10 Λ

βΟ H-P -P-P IQ-PH CO β>, H-P

eh a βω oo hoh η ο Η βω ena eh a maw m a & o Ena 27 150186 • ri

above 1 CM H v £> ITV O- O

SbO · »· * ·> ·>» ·> 3 σ \ -tf t> - m o cd 3 bo 3 h <r ro i

0 S3 P

H H CO

0) S3 s- • d Ό

Η H

II

-------

H

! «Bo i β CO I 0) (ϋβ-Η <1- σ \ cn ro cm bf) 0) Hί H ·« »» »· * · co 3 cd s -d · σ \ o σ> cm <ft Ό>, +> s ro vo h 1 +> 3 3 to CfrP above P to co +>

H <D

ρ -μ 3 >> H 0) Η H + _, o h, ¾ in m ohh 3 p cd 3 ti S P >> +> <0

ctf 01 X

cd +>

Si O -----: ----

<N

H

+>

Pi ^

ω S

m 3 x-N rovo rocoocvj <! α u o cm m o h oo

Eh ωο ro cm cm ro ro cm bD - s

H

j? P +> +> cd i i co +> o o i ^ o o C0 S Ή OH 3 · Η

O OH S t >> OH

Ή βΉ OP S Η

Η O Μ S3 H CO

Η SI HP ΟΙ Μ γΛ'- 'Ο I ΟΗ Ο ΟΗ 0+>> *>,

Ρ Ο! » ί »'-' HP

+> ί> »Ρ Η I bp 3

Si Η 3 bO Μ S3 -Ρ Ο hOP 3 Η 0) I Η 3 I <»Ρ Η +>« Λ Ρ CDP Η I >> I θ h0 Η— 'tV' ΟΟ Ο >> I Ρ. 3 Ο 3 © Μ Ρ 10 Ο 0) 3 0) _ _ ^ 3 Ρ Η 3 Ρ ftp C «U Λ φ 0) Ρ ftp -HP · Η

• d HIHCDP31DPPP

3 3 ^ 3 H cd PH 3 cd cd W

| D P 3 PSO '-' S O O O

w 0) 'p · Η CO Ρ · Η · Η Η

CQp CO PH HP Η Η H

HP H 0) H 3 0) Η Η H

wo) msio HS CO CO CO

28 150186 ° cfl ft

/ · -V

above bO S S3 01 H & 0β 0 d ΉΗ

• SI

I * ΐ «> N. Λ n m c \ l O CM O IS« * * | .h '1 2 3 4 5 ° 8 * 3 1 b03 bO to I ΦΗ taQH CO β ΌΡ 1 d to S3 CMl

W

5

EH

I I H

Η I P H £ *>

j? P Ο I O P .3P PP

2 o -pco Ο β H CO -Pcfl Φ d 3 β a> ο ϊ >> φη ίο mo so p OS Η Η Η Η Η · Η S Η Ο Ή CO S OH bO £> M βΗ OH 3Η Ο βΗ ββ I Ο Η S3 Η Ο • η ο ο μ ο-ρ ^ βω ο μ S to

Η Ο S I Η 0) Sh HI βΙ HI

• Η >> +> Η'- '> »Η Φ Ο Η Η'" "ο ^ µ η co oh ft3.3 Ρ 9w! Ο bOO Ο >> ρ Ρ Ρ> ηΡ ρ>,> »ί >>, β β Η >> Ρ β'- 'Φ Η 3 >> Ρ Η -Ρ Ρ ΦΗ Η 3 ΡΟΗ bap Η13 bp3 β Η D bDP Η β>, 3 1 bOP 3 Ρ ο ρ> »ία 31 Ό ®Λ Ο-Ρ 3 ι ω ι 4

ft I ΦΡ '-'Λ + ί Η I ΦΡ HP

ρ ο ^ Η'- "'-' • Ρ φ η ^ ω ββ> Π HOS Ρ) 3 >> ι Ρ» ι s ftO) ftw> ιΗ ο ο ω 3 «ρ ω Μ Η, 3 Ο Η Ρ> > β βΛ Ρ · Η β · Η <Ο β βρ β Ρ 330 ftp <DP ft3!

CD PCD ftl P P S HO HI HI Ρ P

T3 —η H ^ I <DH ΌΗ β '· "' β« '"' 3 CO

β CO> Ό β PSO Ρβ P3 Ο Ο 5

β xj φ voO M P '-' Φ v- "φ Η H

pp M p Μ β >> HP 01Λ m3 Η H

ΦΦ HP HOH βΦ HP HP Η H

Eh S PQ Φ PPfibO EH S Ρ3Φ ($ CD W W

150186 '29 «Μ Φ 1—1 ο \ ο Η -' §Η

Λ g ΙΛ CM <1- tO

• pj 2 * «* λ S 3 Η Ο IS Η

and tji HH

Εθ <1> ί-t W P <0) o b0 £ to o X} H I Λ ro o tol

S

so

H

-P

CO

-p o

tO I H I O OH

OH £ H

£ H Q ro

OH SI

-P S tO HH

CO Η 1 O S

O OH O-P

H OS S £

H S-P H <D

Η H £ bOPi

CO bOP C O

O £ I 0) CD

Λ ω-p H £

• P Hl SI

£ S ^ {Vs O Λ P O Ih • P CD £ 0)

-P Φ, £ Ρ, Λ <O.

bO Η -P H +>

S U Φ £ <D -P P

CO -P H -PH CO cO

U ^ S '-'S O O

CD CO £ i ta Λ Η H

Ό »ri -P Η -P Η H

ti £ 0) £ 0) Η H

D IH S HØ W CO

300186

The test mixture was observed during boiling and subsequent cooling to detect visual evidence of hydrolytic instability, such as gelling of the mixture or formation of precipitate, and a grade based on the observations was assigned to the orthosilicate ester according to the grade scale: 0 test mixture gelled 3 formation of small precipitate 1 formation of strong precipitate 4 formation of a very small precipitate 2 formation of precipitate 5 clear

The starting material of glycol ether used in these experiments was a liquid consisting of a mixed ethylene / propyl glycol ether having a boiling point of 288 ° C and partially inhibited with additives believed to be sodium nitrite, Agerite Resin D and benzotriazole. This selection was made after preliminary tests in which the orthosilicate ester was boiled (a) with water and (b) with water and glycol ether starting material containing no additives. It was found that these preliminary samples were not sufficiently extreme to evaluate the hydrolytic stability of the studied orthosilicate esters. It was found that the presence of the additives increased the formation of precipitates.

The results of boiling point, hydrolytic stability and rubber swelling test on styrene-butadiene rubber and natural rubber are shown in Table I. The results of the nitrile and chloroprene rubber gurami swells are shown in Tables 2 and 3, respectively.

From the results given in the tables, it appears that the examined orthosilioate esters have satisfactory boiling points and superior hydrolytic stability. In addition, low rubber source values for nitrile and chloroprene gums were obtained. Rubber source values for styrene-butadiene and natural rubber were high, but it is believed that the low chloroprene and nitrile values were far more important in obtaining liquids compatible with all these gums. When the orthosilicate systems are mixed with known starting materials for automotive hydraulic fluids (which are very low in chloroprene and nitrile,

Claims (2)

150186 but good in the case of tyr one-butadiene and natural rubber), rubber nitrate the values of the mixed liquid in comparison with the values of the orthosilicate esters will be lower in the case of styrene-butadiene and natural rubber, but higher in the case of nitrile. - and chloroprene rubber. In Tables 1 and 3, the silicates A to C were glycol monomethyl orthosilicates which were not in accordance with the present invention but prepared in the same manner as in Examples 1 to 10. Si-licate A was tris (triethylene glycol). monomethyl ether-1-butyl silicate, which upon analysis was found to contain 5.0% by weight of Si (theoretically, 4.74%). Silicate B was tetra- (triethylene glycol monomethyl ether) silicate containing 3.77 wt% Si (theoretically 4.1%). Silicate C was bis (tripropylene glycol monomethyl ether) bis (triethylene glycol monomethyl ether) silicate containing 4.17 wt% Si (theoretical 3.78). Patent claims: 1. Orthosilicate ester of the general formula: R ^ O y0R3 \ / Si 2 / \. R 2 O OR 1 for use as a hydraulic fluid or as a component therein, characterized in that r 1, R 2, R 2 and R 2 have the general formula R 5 R 6 - - CH- CH-0 - R - - n