CA1154428A - Hydraulic fluids containing cyano derivatives of cyclic ketals and acetals - Google Patents

Abstract

ABSTRACT
Hydraulic fluids having high wet equilibrium reflux boiling points, good chemical stability and other desirable characteristics are made from certain cyano--substituted derivatives of cyclic ketals or acetals of the formula wherein A, B and R are specified radicals.

28,172-F

Description

HYDRAULIC FLUIDS CONTAINING
CYANO DERIVATIVES OF CYCLIC
KETALS AND ACETALS

This invention relates to hydraulic fluids which maintain high wet equilibrium reflux boiling points on exposure to or contamination with moisture. The fluids are used in devices operated by fluid pressure, such as hydraulic brakes, clutches, fluid transmissions, shock absorbers, power steering and control devices for aircraft, ships, automobiles and other vehicles, artillery recoil mechanisms, door checks, jacks and other hydraulic devices adapted for transfer of mechanical energy.

A hydraulic fluid adapted for the above uses must meet a variety of requirements. It should be chemi-cally stable, nearly nonvolatile, of low flammability, and yet should remain a homogeneous flowable liquid at -temperatures as low as -40C. Additionally, a hydraulic fluid is subject to moisture contamination which may arise because of the inherent hygroscopicity of the hydraulic fluid, from condensation of moisture from the air, or from physical leakage or defects in the hydraulic system that permit water to enter. The deleterious effects arising from moisture contamination of hydraulic fluids include 28,172-F -l-.

-2 lowering of boiling points, vapor locking, corrosion, hydrolysis, foaming, sludging, freezing, and ice crystal-lization.

Re~uirements to be met for a satisfactory hydraulic fluid, particularly a hydraulic fluid used in motor vehicle hydraulic braking systems, have been established by the United States National Highway Safety Bureau and are known generally as DOT 3 or DOT 4 (DOT
referring to the Department of Transportation~. Included therein are different requirements to be met by proposed hydraulic fluids, such as wet and dry equilibrium reflux boiling point (ERBP), viscosity at -40C, and chemical stability and rubber compatibility standards. A hydraulic fluid satisfying the different testing standards is char-acterized as being a DOT 3- or DOT 4-fluid depending on the particular standard that is met or exceeded by the fluid. Details of this testing procedure are published in the Federal Motor Vehicle Safety Standard, 49 CFR
571.116.

It has been discovered that hydraulic fluids having good physical characteristics are provided by the present invention, which is a hydraulic fluid compo-sition comprising a cyano-substituted cyclic compound of from 5 to 20 carbons of the formula o~A\o N_C\B~C\R

or a mixture thereof, wherein:

-~ 28,17~-F-2-R is hydrogen or a monovalent radical of from 1 to 10 carbons selected from branched or linear alkyl and cyano-, hydroxy-, alkoxy-, acyloxy-, sil-oxy- or organosiloxy-substituted derivatives thereof;
A is a divalent radical of from 2 to 10 carbons selected from alkylene and alkyl-, aryl-, cyano-, hydroxy-, cyanoalkyl-, hydroxyalkyl-, alkoxy-, poly-alkoxy-, acyloxy-, siloxy- or organosiloxy-substi-tuted alkylene; and B is a divalent radical of from 2 to 10 car-bons selected from branched or linear alkylene and ~CH2 tm~OC~2 ~CHtn R'1 wherein each R'l is hydrogen, methyl or ethyl and m and n are integers equal to or greater than 1; and a remainder comprising at least one compound selected from cyano-substituted cyclic compounds of the above formula, but different from the above cyano-substi-tuted cyclic compounds, hydraulic fluid components and hydraulic fluid additives.

The cyano-substituted cyclic ketals and acetals of the invention have been found to possess desirable qual-ities ~aking them suited for use in hydraulic fluid formu-lations. In particular the compounds exhibit high dry and wet equilibrium reflux boiling points as well as low vis-cosities at -40C and good chemical stability. The com-pounds including mixtures thereof may be combined in major or minor proportion with other hydraulic fluid components and/or additives into hydraulic fluid formulations having qualities tailored for specific applications.

28,172~F -3-_4_ The cyano-substituted compounds for use accord-ing to this invention may be prepared by several proce-dures. According to one such procedure, a reactive car-bonyl- or dialkoxy-contaiIIing compound of the formula o ,OD
N--C-B-C-R or N_C-B-C~R
OD

wherein B and R are as previously defined and D is C1 4 alkyl, is first reacted with an aliphatic diol or polyol. The product is a cyclic ketal or acetal of formula I wherein A is the remnant of the original diol or polyol. Practically any diol or polyol having two hydroxy moieties on adjacent or next adjacent carbon atoms and optionally substituted with the previously named substituents may be employed to produce the com-pounds of the instant invention. The process is well--known, one similar to it having been previously described in Or~anic Synthesis, Coll. Vol. 3, 502.

The reaction is carried out in the presence of an acidic catalyst, for example, sulfonic acid, sul-fonic acid resin or other strong acid resin that ade-guately catalyzes this type of reaction. The catalyst may be employed in a molar ratio compared to the cyano--substituted ketone or aldehyde reactant of from about 0.0001/1.0 to about 0.1/1.0, preferably from 0.001/1.0 to 0.05/1Ø

It is convenient to conduct the reaction in a solvent, preferably such a solvent that easily forms an azeotropic mixture with water allowing the rapid 28~172-F -4-removal of by-product water formed during the reaction.
Further preferred are solvents that do not additionally form azeotropic mixtures with either the cyano-substituted ketone or polyol starting reactants. Suitable solvents include benzene, toluene, petroleum ether, and chlori-nated aliphatic solvents.

The reaction may also be conducted without a solvent in which case the water or lower alcohol formed during the reaction may be xemoved by direct distilla-tion preferably at reduced pressure and temperature tolimit the formation of oligomers which form at elevated temperatures.

The reaction is conducted at temperatures from about 0C to about 200C, depending on the reac-tants, pressures and other process conditions employed.

The required reaction time will vary depend-ing on the reactants and temperatures employed. Gener-ally reaction times from about 1 to about 48 hours suf-fice to convert substantially all of one starting reac-tant employed in limiting quantities.

Either reactant may be employed in largeexcess. Molar ratios of cyano-substituted ketone to polyol ranging from about 20/1 to about 1/20 are oper-able. It is preferred to employ the reactants in nearly equal molar proportions, for example in a molar range from about 2/1 to about 1/2. Most preferred is a range from about 1.2/1.0 to about 1.0/1.2. An excess of the lower boiling reactant whether polyol or cyano-substi-tuted ketone or aldehyde may be employed to insure com-plete reaction of the higher boiling reactant. This . .

28,172-F -5-, ~ .

.

procedure simplifies the separation of the cyclic ketal or acetal product from reactants by dlstillatlon by pro-viding a mixture of components having the maximum possi-ble difference in boiling points.

It is of course equally suitable to add the nitrile substituent to the previously formed cyclic ketals or acetals to produce the desired substituted compounds.
Accordingly, a compound containing terminal e1hylenic unsaturation but otherwise similar to the pre~iously iden-tified reactive carbonyl- or dialkyl-containing compounds may be reacted with the diol or polyol. When conducted in the presence of hydrogen chloride a chlorinated cyclic ketal is produced which may then be reacted with sodium cyanide in known manner to produce the desired product.

lS Furthermore, substituents to R or A such as alkoxy, ~poly)alkoxy, siloxy, organosiloxy, and acyloxy may be added subsequent to formation of the cyclic ketal or acetal by reaction of suitable reactive precursors with hydroxy-substituted cyclic ketals or acetals formed as above described. By reactive precursors are meant compounds that may be reacted with hydroxyl functionality according to known chemical processes to replace the hydro-gen of the hydroxyl functionality. For example, by use of a Williamson synthesis alkyl and aralkyl moieties may be substituted for hydrogen. Similarly, alkylene oxides or mixtures thereof may be used to form ether functionality, producing hydroxy-substituted alkoxy or polyalkyleneoxy substituents which may of course be capped to replace pen-dant hydroxides with alkyl or aralkyl moieties by means of a Williamson synthesis. Acid halides such as acetyl 28,172-F -6-chloride or halo-substituted silanes, organosilanes or organooxysilanes, such as chlorosilane, trimethylchloro-silane or trimethoxychlorosilane, may also be reacted with the hydroxy-containing compounds in the presence of an acid acceptor to produce acyloxy-, siloxy or organo--substituted siloxy derivatives, respectively. All such '~ substantially inertly-substituted compounds are included within the scope of the instant invention.

Other methods of forming the compounds employed in the present invention may also be utilized without departing from the scope of the invention.

Preferred cyano-substituted compounds of for-mula I for use as components in hydraulic fluids include 2-cyanoalkyl derivatives of 1,3-dioxolane or 1,3-dioxane.
Also preferred are their further ring-substituted alkyl-, hydroxy- or hydroxyalkyl- derivatives. Most preferred cyano-substituted compounds are 2-l2-cyanoethyl)-1,3--dioxolane, 2-(3-cyanopropyl)-1,3-dioxolane, 2-(2-cyano-ethyl)-2-methyl-1,3-dioxolane, 2-(3-cyanopropyl)-2--methyl-1,3-dioxolane, 2-(2-cyanoethyl)-4-hydroxymethyl--1,3-dioxolane, 2-(3-cyanopropyl)-4-hydroxymethyl-1,3--dioxolane, 2-(2-cyanoethyl)-2-methyl-4-hydroxymethyl-1,3-dioxolane, 2-(3-cyanopropyl)-2-methyl-4-hydroxymethyl--1,3-dioxolane, 2-(2-cyanoethyl)-4-methyl-1,3-dioxolane, 2-(3-cyanopropyl)-4-methyl-1,3-dioxolane, 2-(2-cyanoethyl)--2,4-dimethyl-1~3-dioxolane, 2-~3-cyanopropyl)-2,4-dimethyl--1,3-dioxolane, 2-(2-cyanoethyl)-5-hydroxyl-1,3-dioxane, 2-(3-cyanopropyl)-5-hydroxyl-1,3-dioxane, and mixtures thereof.

~ 28,172-F -7-', A particularly preferred hydraulic fluid com-position having exceptionally high wet equilibrium reflux boiling point and good low temperature viscosity comprlses a mixture of cyano-substituted cyclic compounds selected from 2-(2-cyanoethyl)-1,3-dioxolane, 2-(2-cyanoethyl)-4--methyl-1,3-dioxolane, 2-(2-cyanoethyl)-4-hydroxymethyl--1,3-dioxolane and 2-(2-cyanoethyl)-5-hydroxyl-1,3-diox-ane. The latter two compounds being formed for example by the reaction of glycerine with ~-cyanopropionaldehyde.

As is well-known in the art, suitable quali-ties for a hydraulic fluid are rarely found in one com-pound. However, a composition comprising several suit-able compounds may be formulated to produce a hydraulic fluid composition having satisfactory properties.

Suitable hydraulic fluids accorcling to the present invention meeting or exceeding DO~' 4 requirements comprise the cyano-substituted cyclic compounds of for-mula (I) present in major or minor proportions, preferably at least about 5 percent by weight. Particular desirable qualities in the hydraulic fluid may be ob-tained by com-bining with such compounds additional hydraulic fluid com-ponents and/or additives as is well-known :in the art. Most preferred according to the invention are fluids consisting essentially of one or more of the cyano-substituted cyclic compounds of formula (I) in an amount from about 10 percent to about 90 percent by weight, one or more hydraulic fluid components in an amount from about zero to about 90 percent by weight and one or more hydraulic fluid additives from about zero to about 10 percent by weight.

28,172-F -8-.

. .

By the term "hydraulic fluid component" or simply "component" is meant a solid or liquid chemical compound which when employed as an ingredient in a hydraulic fluid is not substantially chemically reac-tive with other components or additives or with thecyano-substituted cyclic compounds of the invention, and which is substantially immune to decomposition or reac-tion under the hydraulic fluid operating conditions to which it is exposed and the mechanical systems with which it comes into contact. Particular properties such as - boiling point or viscosity may vary depending on the application for which the hydraulic fluid is used and the operating conditions to which it is exposed. Selection of particular components and mixtures thereof to meet various design criteria may easily be determined by the skilled artisan.

By the term "hydraulic fluid additive" or sim-ply "additive" is meant a solid or liquid chemical com-pound usually added in a small amount to a hydraulic fluid composition to control or modify various chemical or physi-cal properties of the components of the hydraulic fluid.

Preferred hydraulic fluid components include conventionally known components, such as glycols, glycol ethers including formals, glycol esters, glycol ortho-esters, borate esters and silicons.

Specifically, the glycols include (poly)alkyl-ene glycols of the formula HO~R'O)n-H wherein each R' is the same or different and is a linear or branched C1 6 alkylene and n is a positive number up to about 50. Such ~poly)alkylene glycol hydraulic fluid components are well--known in the art.

28,172-F -9-`:
, 0 The polyglycol mono- and diethers and for-mals known as conventional hydraulic fluid components include compounds of the formula R'1O~R'O)n-R2 and R lO~R O)n-CH2tOR')n-OR2 wherein R' and n are as previ-ously defined, R'1 is a Cl 4 linear or branched alkyl, hydrogen or phenyl radical, and R2 is a C1 4 linear or branched alkyl or phenyl radical.

The glycol ester conventional hydraulic fluid components include compounds of the formula ~COOR4~0R5tnOR2 o O
R3~ and/or R6-COtR7OtyC~R~
COOR4~0R5tnOR2 wherein n and R2 are as previously defined, R3 is a :15 straight- or branched-chain alkylene group containing at least 2, preferably 2 to 8, carbon atoms, each R4 or R5 is the same or different and is a straight or branched .~alkylene radical containing from 1 to 4 carbon atoms, each R6 is the same or different and is a methyl or ethyl group, each R7 is the same or different and is an ethylene or propylene group and y is an integer from 1 to 8, pref-erably an integer such that the total number of carbon atoms in the tR7Ot group is from 4 to 12.

Glycol ortho ester hydraulic fluid components known and used in conventional fluids are such glycol ortho esters of the formula ORg ORg ORg R8-C-ORg or R8 C Rlo C R8 ~ ORg ORg ORg : 28,172-F -10-wherein each R8 is a hydrogen atom, an alkyl radical containing from 1 to 5 carbon atoms, or the same as Rg;
each Rg is the same or different and each is an alkyl radical containing from 1 to 4 carbon atoms, an oxyalkyl-ene glycol monoether radical, or a polyoxyalkylene glycolmonoether radical containing from 2 to 20 alkylene oxy-units; and R1o is an alkylene radical containing from 1 to 12 carbon atoms.

Numerous varieties of borate ester hydraulic fluid components are known. These may be depicted by the following formulas:

B[~oRlltpoRl2]3 R12~R11)p - B O B~ ( lltp 12 R12tR11)p/ (OR11tpOR12 :: ~R12~R11 )p _ B_O_R
lR120tR11O)p / 13 B~R14/B

: 14 28,172-F -11-,.

R~B-R14-B~R14 wherein each R11 is the same or different and is a straight or branched C2 4 alkylene group, each R12 is the same or dif~erent and is hydrogen or a C1 4 alkyl group, each p is the same or different and is an integer of from 1 to 10, q is an integer of from 2 to 6, R13 is the residue of a di- or polyhydroxy organic compound hav-ing a number of reackive hydroxy groups equal to q, and each R14 is the same or different and is the residue of a dihydroxy organic compound which residue is attached to each boron atom via an oxygen atom.

A mixture of such borate ester compounds together with compounds containing reactive hydroxyl functionality generally results by means of alkoxide exchange in production of an equilibrium mixture of such compounds in the resulting hydraulic fluid.

The foregoing list of known conventional hydraulic fluid components are more fully described in U.S. Patent 4,093,554 issued to Jayne et al., June 6, 1978.

Suitable silicone conventional hyd~aulic fluids are the monomeric or polymeric organosilane or organosil-oxane compounds including such compounds that are substi-tuted with compatible substituents, e.g., alkyl-, aryl-, alkoxy-, aryloxy-, alkylene-, alkylenedioxy-, (poly)oxy-alkylene-, cy~no-, cyanoalkyl-, hydroxyalkyl-, carbonyl-or mixtures thereof.
~, ~`..'`
~ 28,172-F -12-.~ :

.

These silicone hydraulic fluid components are well-known. Suitable compounds have been described in numerous references of the prior art, for example, U.S.
Patents 3,507,898; 4,075,115; and 4,088,591.

Hydraulic fluid compositions comprising the above-described silicone fluids and the cyano-substituted compounds have been found to be very stable and resistant to separation or crystallization at high or low tempera-tures and to possess improved viscosity characteristics.

Particularly preferred co~ventional hydraulic fluid components are ~poly)alkylene glycols, especially polypropylene glycols having a molecular weight from about 500 to about 2000. Particularly high boiling hydraulic fluids according to the invention may include such poly-propylene glycol components.

Among the various additives which can be added to the hydraulic fluids of this invention are inhib-itors for pH and corrosion control, antioxidants, viscos-ity index improvers, pour point depressants, lubricity agents, antifoamants, stabilizers, demulsifiers, dyes and odor suppressants. Generally, the total amount of addi-tives which may be incorporated into the fluid composition will ~ary depending on the particular composition and the desired properties.

As conventionally used additives of hydraulic fluids in order to inhibit oxidation of the organic com-pounds at high temperatures are diarylamines, e.g., diphe-nylamine, p,p'-dioctyl-diphenylamine, phenyl-,Y-naphthyl-amine, or phenyl-~-naphthylamine. Other suitable antiox-idants are those commonly known as hindered phenols, such 28,172-F -13-as 2,4-dimethyl-6-t-butyl phenol, 2,6-ditertiarybutyl-4--methyl phenol, 2,6-di-t-butyl phenol, 1,1-bis(3,5-di-t--butyl-4-hydroxyphenyl)methane, 3,3',5,5'-tetra-t-butyl--4,4'-dihydroxydiphenyl-3-methyl-4,6-di-t-butyl phenol, and 4-methyl-2-t-butyl phenol.

Other additives which may be used are pheno-thiazine and its derivatives, for example those having alkyl, or aryl groups attached to the nitrogen atom or to the aryl groups of the molecule.

Conventional lubricity additives usefully added to hydraulic fluids include high molecular weight monoethers of polyalkylene glycols, for example, such monoalkyl ethers of polypropylene glycol of 500 or higher molecular weight; mineral oil; and castor oil derivatives, e.g., blown castor oil (castor oil blown with air or oxy-gen while being heated) and castor oil treated with ethyl-ene oxide or propylene oxide.
~.
Other lubricity additives conventionally known include borate esters, e.g., tricresyl borate and borate ester condensates; and phosphorus-containing esters, espe-cially phosphates, e.g., tricresyl phosphate.

Other lubricity agents are orthophosphate or sulfate salts of primary or secondary aliphatic amines having a total of from 4 to 24 carbon atoms, dialkyl citrates having an average of from 3.5 to 13 carbon atoms in the alkyl groups, aliphatic dicarboxylic acids and esters thereof, specific examples being diamylamine ortho-phosphate, dinonylamine orthophosphate, diamylamine sul-fate, dinonyl citrate, di(2-ethyl hexyl)citrate, polyoxy-ethylene sebacate derived from a polyoxyethylene glycol , 28,172-F -14-:

.

¦ '¦ ' , L7~ ~ t ~ fJ

of M.W. 200, polyoxyethylene azelate derived from a poly-oxyethylene glycol of M.W. 200, polyoxyethylene adipate derived from a polyoxyethylene glycol of M.W. 200, poly-oxyethylene/polyoxypropylene glutarate derlved from mixed polyoxyglycols of average M.W. of about 200, diethyl seba-cate, di-2-ethyl hexyl sebacate, and diisooctyl azelate.

Corrosion inhibitors which may be used in the present invention are heterocyclic nitrogen-containing compounds, e.g., benzotriazole and benzotriazole deriva-tives or mercapto benzothiazole. Many amines or deriva-tives thereof are also suitable as corrosion inhibitors, for example di-n-butylamine, di-n-amylamine, cyclohexyl-amine, morpholine, triethanolamine and soluble salts thereof, e.g., cyclohexylamine carbonate.
,;
Phosphites are also good corrosion inhibitors, for example, triphenyl phosphite and diisopropyl phosphite, and certain inorganic salts may be incorporated, e.g., sodium nitrate.

The preceding list of known conventional addi-tives for hydraulic fluids are more fully described inU.S. Patent 4,093,554 previously identified.

The various compounds, cyano-substituted cyclic compounds of formula I, components and additives are formulated into the invented hydraulic fluid by add-ing the compounds in any order and agitating the result-ing mixture until a uniform, homogeneous composition results. Heating to a slightly elevated temperature may be employed as an aid in formulation of the invented hydraulic fluid.

- 28,172-F -15-:`:

The following examples illustrate the present invention.

Examples 1-4 5-Oxohexane nitrile was purified by extract-ing a 33 percent ether solution with a 5 percent aqueous HCl solution to remove basic impurities. The ether frac-tion was dried, filtered and the ether solvent removed by evaporation. Analysis by gas chromatography indicated 5-oxohexane nitrile in 99.8 percent purity remained.

The ketalization reaction of 5-oxohexane nitrile (OHN) with the following hydroxyl-containing compounds was accomplished by refluxing the reactants in the presence of p-toluene sulfonic acid catalyst and toluene solvent in a three-necked glass flask topped with a Dean-Stark trap and a reflux condenser for azeotropic removal of water.
The reaction was continued for the stated time period.
Upon completion of the reaction, the solutions were cooled, the pH adjusted to 7.5-8.0 by addition of solid NaHCO3, then filtered and distilled. Analysis by gas chromatograph determined the ketal as the only product formed in all cases. Yields after distillation were from 60-75 percent. The pertinent data for each exam-ple are as follows:

28,172-~ -16--Reac-Hydroxyl Cata- tion %
Exam- Reactant OHN lyst Time Conver-ple Name moles moles moles (hr) sion 2-(3-cyano- ethylene propyl)-2- glycol 1 methyl-1,3- 4.0 3.24 0.003 24 98.5 dioxolane 2-(3-cyano- propylene propyl)- glycol 2 2,4-dimeth- 3.1 3.0 0.003 48 99.3 yl-1,3-di-oxolane 2-(3-cyano-propyl)-2-methyl-4-hydroxy- glycerine

3 methyl-1,3- 2.7 3.3 0.003 48 98.7 dioxolane 2-(3-cyano- 1,3-pro-propyl)-2- panediol

4 methyl-1,3- 3.1 3.0 0.003 48 9g.6 dioxane The compounds prepared above were tested for use as components in a hydraulic fluid. Results of this testing are contained in Table I.

28,172-F -17-Examples 5-8 Anhydrous hydrogen chloride was bubbled into a solution of 304 g of propylene glycol and 300 ml chloro-form cooled to a temperature of -14C. While maintaining a slight positive pressure, 168 g of acrolein was added dropwise with stirring over a 90-minute period. The tem-perature was maintained below -10C and the hydrogen chlo-ride addition continued with stirring for an additional hour.

When stirring was finally ceased and the tem-perature allowed to slowly increase to room temperature a cloudy suspension remained which separated into two layers. The lower layer, containing 2-(2-chloroethyl)-4--methyl-1,3-dioxolane, was drawn off, partially neutra-lized with 3 ml of triethylamine and washed with 50 ml of saturated sodium carbonate solution. The organic layer was again separated, dried over calcium sulfate and heated ln vacuo to remove residual acrolein and chloro-form. Final vacuum distillation yielded 221 g of 2-(2-20 -chloroethyl)-4-methyl-1,3-dioxolane, bp. 39-41C @
0.05 torr.

This compound (190 g) was then combined in 500 ml of ethylene glycol monomethyl ether and sodium cyanide (64 g) and refluxed at 125C for about 7 hours.
Additional sodium cyanide (11 gj was added and refluxing continued for 3 more hours. The mixture was cooled and the salt separated by filtration. Concentration and vacuum distillation of the filtrate gave about 140 g of a colorless li~uid 2-(2-cyanoethyl)-4-methyl-1,3-dioxo-30 lane, bp. 65-67C @ 0.05 torr.

28,172-F -18-' , Substantially repeating the above reaction conditions, additional compounds were also prepared.
The pertinent data for each example are:

Ethylenically Polyhydroxy Unsaturated Example Compound Reactant AldehYde 2-(2-cyano- propylene acrolein ethyl)-4- glycol -methyl-1,3--dioxolane 6 2-(2-cyano- ethylene acrolein ethyl)-1,3- glycol -dioxolane 7 2-(2-cyano- ethylene methylvinyl ethyl)-2- glycol ketone -methyl-1,3--dioxolane mixture:
8 2-(2-cyano- glycerine acrolein ethyl)-4--hydroxymethyl--1,3-dioxolane/
2-(2-cyanoethyl)-

-5-hydroxy-1,3--dioxane*

*The percentage of each component in the mixture was not determined.

The following Table I shows the properties of the compounds prepared in Examples 1 to 8.

28,172-F -l9-~ o o o ~ ~a C) I I O I I I ~; F
o ~ V V O O
.~: . . U~
E~
,~
~1 ~ t~ O o X X ~ ,~
rl ~ O ~ O O I I I ~ ~ O U
U~ ~ ~ Z
1~ v v O O
. .
a U~ V ~ O
~o X X
~1 ~ ~ ~ ~ o _ ~1 ~1 ~1 ~1 ~ U~
~ ~ U~
a u~ ~
~ I ~ 0 a~
X X ~U
t~
.,~ _ ~ ~1 N ~O t~ ~ t~ ~ ~ ~3 ~ ~3 ~ O ~1 1~ ~ ~i . . . . . I o o >
_ ~ ~ ~ dl ,~ O ~1 1 ~ ~
3 . . s~ ~n U~ ~ ~ $ o O rl ~ ~ X X ~ ~
~n ~ q~ o ~1' ~ ~ ~ 0 ~ ~ , o ~1 o ~ ~ o ~ o ~ t~ o ~1 ~1 o o ~ o o a) -~
Q u c~ ~ L~ ~n m A c~ o ~,q o A u~ 0 a ~1 o ~1 ~1 ~ a~
:> d1 o o ~ ,1 ~ ~ ~ C~ ~ o U) ~ U~
~ r~ 0 t` t` 1` 0 CD d' u~ :
V 3 ~1 ~ ~1 ~1 ~1 ~ 1 N ~1 ~1 ~1 -~1 o h ~
uu ~3 cs~ ~ ~ co ~ ~ In o dt ~ c~l ~ ~ ~ I I I o a ~
U
X
u a~

~ U
:. ~ 0~ ~, . ~ ~ U~
\

o ~`
_ ~ ~ ~ V
a X + O E~ d~

28, 172-F -20-:

, : :
.
:

Claims (8)

1. A hydraulic fluid composition comprising a cyano-substituted cyclic compound of from 5 to 20 car-bons of the formula or a mixture thereof, wherein:

R is hydrogen or a monovalent radical of from 1 to 10 carbons selected from branched or linear alkyl and cyano-, hydroxy-, alkoxy-, acyloxy-, sil-oxy- or organosiloxy-substituted derivatives thereof;
A is a divalent radical of from 2 to 10 carbons selected from alkylene and alkyl-, aryl-, cyano-, hydroxy-, cyanoalkyl-, hydroxyalkyl-, alkoxy-, poly-alkoxy-, acyloxy-, siloxy- or organosiloxy-substi-tuted alkylene; and B is a divalent radical of from 2 to 10 car-bons selected from branched or linear alkylene and 28,172-F -21-wherein each R'1 is hydrogen, methyl or ethyl and m and n are integers equal to or greater than 1; and a remainder comprising at least one compound selected from cyano-substituted cyclic compounds of the above formula, but different from the above cyano-substi-tuted cyclic compounds, hydraulic fluid components and hydraulic fluid additives.

2. A hydraulic fluid composition as claimed in Claim 1 wherein the cyano-substituted cyclic compound or a mixture thereof is present in a concentration of at least 5 percent by weight.

3. A hydraulic fluid composition as claimed in Claim 2 consisting of the indicated parts by weight of the following:

(a) from 10 percent to 90 percent of one or more of the cyano-substituted cyclic compounds;
(b) from zero to 90 percent of one or more hydraulic fluid components; and (c) from zero to 10 percent of one or more hydraulic fluid additives.

4. A hydraulic fluid composition as claimed in Claim 3 wherein the hydraulic fluid components and additives are conventional hydraulic fluid components and additives.

5. A hydraulic fluid composition as claimed in Claim 4 wherein the conventional hydraulic fluid com-ponent is selected from:

28,172-F -22-(a) a polyalkylene glycol of the formula HO(R'O)nH wherein R' is each occurrence the same or different and is a linear or branched C1 6 alkylene and n is a positive number up to 50;
(b) a polyglycol mono- or diether or poly-glycol formal of the formula R'lO(R'O)nR2 or R'lO(R'O)n-CH2(OR')nOR2 wherein R' and n are as previously defined, R'1 is hydrogen, C1-4 linear or branched alkyl or phenyl, and R2 is C1-4 linear or branched alkyl or phenyl;
(c) a glycol ester of the formula or wherein n and R2 are as previously defined, R3 is straight or branched C2 8 alkylene, each R4 or R5 in each occurrence is the same or different and is a straight or branched-chain C1-4 alkylene, R6 is each occurrence C1-2 alkyl, R7 is each occurrence C2-3 alkylene and y is an integer from 1 to 8;
(d) a glycol orthoester of the formula or 28,172-F -23- wherein R8 is each occurrence hydrogen, C1-5 alkyl or R9, R9 is each occurrence C1 4 alkyl, an oxyal-kylene glycol monoether radical or polyoxyalkylene glycol monoether radical of from 2 to 20 oxyalkylene units, and R10 is C1-12 alkylene;
(e) a borate ester of the formula B[(OR11)pOR12]3 or 28,172-F -24- wherein R11 is each occurrence straight or branched C2 4 alkylene, R12 is each occurrence hydrogen or C1 4 alkyl, p is each occurrence an integer from l to 10, q is an integer from 2 to 6, R13 is the resi-due of a di- or polyhydroxy organic compound having a number of reactive hydroxy groups equal to q, and R14 is each occurrence the residue of a dihydroxy organic compound which residue is attached to each boron atom via an oxygen atom;
(f) monomeric or polymeric organosilanes or organosiloxanes or such compounds substituted with alkyl-, aryl-, alkoxy-, aryloxy-, alkylene-, oxy-alkylene-, alkylenedioxy-, polyoxyalkylene-, cyano-, cyanoalkyl-, hydroxyalkyl- or carbonyl- substituents or mixtures thereof; and (g) mixtures of (a) through (f).

6. A hydraulic fluid composition as claimed in Claim 5 wherein the conventional hydraulic fluid compo-nent is a (poly)alkylene glycol or a mixture thereof.

7. A hydraulic fluid composition as claimed in Claim l wherein the cyano-substituted cyclic compound is selected from 2-(2-cyanoethyl)-1,3-dioxolane, 2-(3-cy-anopropyl)-1,3-dioxolane, 2-(2-cyanoethyl)-2-methyl-1,3--dioxolane, 2-(3-cyanopropyl)-2-methyl-1,3-dioxolane, 2-(2-cyanoethyl)-4-hydroxymethyl-1,3-dioxolane, 2-(3-cyan-opropyl)-4-hydroxymethyl-1,3-dioxolane, 2-(2-cyanoethyl)-28,172-F -25--2-methyl-4-hydroxymethyl-1,3-dioxolane, 2-(3-cyanopropyl)--2-methyl-4-hydroxymethyl-1,3-dioxolane, 2-(2-cyanoethyl)--4-methyl-1,3-dioxolane, 2-(3-cyanopropyl)-4-methyl-1,3--dioxolane, 2-(2-cyanoethyl)-2,4-dimethyl-1,3-dioxolane, 2-(3-cyanopropyl)-2,4-dimethyl-1,3-dioxolane, 2-(2-cyano-ethyl)-5-hydroxyl-1,3-dioxane, 2-(3-cyanopropyl)-5-hydrox-yl-1,3-dioxane, and mixtures thereof.

8. A hydraulic fluid composition as claimed in Claim 7 wherein the cyano-substituted cyclic compound is selected from 2-(2-cyanoethyl)-1,3-dioxolane, 2-(2--cyanoethyl)-4-methyl-1,3-dioxolane, 2-(2-cyanoethyl)-4--hydroxymethyl-1,3-dioxolane, 2-(2-cyanoethyl)-5-hydroxy--1,3-dioxane, and a mixture thereof.

28,172-F -26-