CA1077047A

CA1077047A - Additives for functional fluids

Info

Publication number: CA1077047A
Application number: CA244,033A
Authority: CA
Inventors: Alan F. Popplewell; David R. Clark
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1975-01-23
Filing date: 1976-01-21
Publication date: 1980-05-06
Also published as: CH597198A5; SE426243B; BE837796A; DE2601719C2; SE7600160L; BR7600385A; AU1050876A; NL7600732A; JPS5198276A; AT343655B; JPS6224427B2; ZA76372B; SU582759A3; ES444523A1; DE2601719A1; IT1060209B; DD123745A5; GB1466558A; FR2298543A1; PL97084B1

Abstract

Abstract of the Disclosure Aminomethylated heterocyclic compounds of the formula I

I

wherein X is N or CR wherein R is hydrogen or a lower alkyl residue, A is a benzene or naphthalene residue, each unsubstituted or substituted with one or more alkyl or aralkyl residues and R1 and R2 are the same or different and each is a residue of formula R3O{(alkylene) O}x (alkylene) wherein R3 is hydrogen or alkyl and x is 0, 1, 2, 3 or 4; an alkenyl or a cyanoalkyl residue or R1 has its previous significance and R2 is hydrogen, al-kyl, cycloalkyl, aralkyl or a residue having the formula:- wherein A and X have their previous significance, are prepared by Mannich reaction of benzotriazoles or naphthotriazoles with formaldehyde and primary or secondary amines. The products consists mainly of the l-isomers. The compounds are metal passivators and are used as additives for functional fluids being in contact with metals. Those compounds with polar substituents at the amino-group are especially usable in water-based fluids such as anti-freeze or metal-working fluids.
Those with apolar amino-substituents are preferred for oil-based systems such as lubricants or hydraulic fluids.

Description

1~377~)47 The present invention relates to additives for functional fluids.

Benzotriazole and derivatives thereof have been known for many years to be effective metal passivators, especially copper passivators, for use in a range of substrates. Benzotriazole itself and many of its derivatives have, however, limited appli-cation because of their poor solubility, particularly in mineral oils.

We have now ound certain previously unknown benzotriazole deri-vatives which combine an improved level of solubility in a wide range of functional fluid media, includ;ng aqueous and oil-based media, with a high level of metal passivation.

Accordingly, the present invention provides a new compound having the formula:-N

A ~ X
N ~ / R
CH2N \

wherein X is N or CR wherein R is hydrogen or an alkyl residuehaving from 1 to 4 carbon atoms, A is a benzene or naphthalene residue, each unsubstituted or substituted with one or more alkyl residues having from 1 to 12, especially 1 to 4 carbon atoms or aralkyl residues having from 7 to 9 carbon atoms, ~ 2 -.- .. -,i.. - .. . ............
--''':' '':,-:' . ~ ' .' :.

. ....... . .. .
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~ .. ; :

especially ~ dimethylbenæyl, and Rl and R2 are the same or different and each is a residue of formula R30[(alkylene)0]x (alkylene) wherein R3 is hydrogen or alkyl having from 1 to 20 carbon atoms, "alkylene" is a straight- or branched chain alkylene residue having 2 or 3 carbon atoms and x is 0, 1, 2, 3 or 4; an alkenyl residue having from 2 to 20 carbon atoms;
or a cyanoalkyl residue having from 2 to 5 carbon atoms; or Rl has its previous significance and R2 is hydrogen, alkyl having from 1 to 20 carbon atoms, aryl having from 6 to 10 carbon atoms, cycloalkyl having from 5 to 12 carbon atoms, aralkyl having from 7 to 9 carbon atoms, or a residue having the formula:-II

N ~

wherein A and X have their previous significance.

In a modification of compounds falling within the general formula I, there are provided compounds having the formula:-~ ~ N ~

R6 ~ ~ / IA

CH2N ~

A` _ 3 _ - : ~, :: : . .

.. . . . ..

- : :: ~ . .. ~ . - : , 10~77~47 wherein X has its previous significance and is preferably N and R4 and R5 are the same or different and each is alkyl having from 1 to 20 carbon atoms, aryl having from 6 to 10 carbon atoms, cycloalkyl having from 5 to 12 carbon atoms or aralkyl having from 7 to 9 carbon atoms, and R6 is aralkyl having from 7 to 9 carbon atoms, preferably ,~-dimethylbenzyl.
The compounds of formula I are Mannich bases and preferred compounds are firstly those wherein the residue X is N and the residue A is a benzene residue, as well as the compounds of formula IA as }.ereinbefore defined.
Moreover~ it is preferred that the substituent on the N atom of the compound of formula I constitutes a polar function. It is particularly pre-ferred that at least one of Rl and R2 and preferably each, is a residue of formula R30[(alkylene)0]x-(alkylene) - wherein R3 has its previous significance and R3 is preferably H, x is preferably 0.
When X is C-R, and R is alkyl having from 1 to 4 carbon atoms, R is preferably a methyl group.
If the residue A is a substituted benzene or naphthalene residue, the preferred residue is a benzene residue, and the substituents are preferably alkyl groups having fTom 1 to 4 carbon atoms, especially methyl or aralkyl, especially ~,~-dimethylbenzyl.

~ . ,, ,. : .
;:, ' ~ .

When Rl and/or R2 is an alkenyl residue, this residue preferably contains from 3 to 20 carbon atoms, examples being allyl, butenyl, octenyl, decenyl, dodecenyl, tetradecenyl and octade-cenyl (oleyl).

When Rl and/or R2 is R30[alkylene)0]x(alkylene)- preferred instances are those wherein R3 is hydrogen or alkyl having from 1 to 18 carbon atoms, especially 1 to 8 carbon atoms, for instance hydroxyethyl, methoxyethyl, n-butoxyethyl, methoxy-ethoxyethyl, n-butoxyethoxyethyl, n-octyloxypropyloxy- residues.
Preferred cyanoalkyl substituents Rl and/or R2 are cyanomethyl and cyanoethyl.

When Rl has one or other of the foregoing meanings R2 may have further meanings i.e. hydrogen, alkyl, aryl, cycloalkyl, aralkyl or a heterocyclic residue or a residue of formula II wherein A
and X advantageously have their respective preferred meanings as hereinbefore described.

When R2 is alkyl it preferably contains from 1 to 12 carbon atoms; when R2 is aryl it is preferably phenyl or naphthyl; the preferred cycloalkyl residue R2 is cyclohexyl; and the preferred aralkyl residue R2 is benzyl.

Preferred instances of R4 and R5 are the same as those indicated for R2.

:
:: :

107709~7 However the most preferred compo~mds of the present invention are those of formula I wherein A is benzene, unsubstituted or substituted by methyl or dimethylbenzyl and wherein Rl and R2 are the same or different and each is R30E(alkylene)O]x-(alkyl-ene) or Rl is such a residue and R2 is hydrogen or lower alkyl and R3 is hydrogen or lower alkyl; x is preferably 0.

Specific examples of compounds in accordance with the present invention are:
l-diethanolaminomethyl benzotriazole l-diethanolaminomethyl benzotriazole l-diisopropanolaminomethyl benzotriazole l-diisopropanolaminomethyl benzimidazole N,N-bis(l'-benzotriazolylmethyl)ethanolamine N,N-bis(l'-benzimidazolylmethyl)-n-propanolamine N,N-bis(l'-benzotriazolylmethyl)-iso-propanolamine 1-tN-methyl-ethanolaminomethyl)benzotriazole N,N-bis(l'-benzimidazolylmethyl)-3-amino-3-methylbutanol N,N-bis(l'-benzimidazolylmethyl)-3-methoxypropylamine l-diallylaminomethyl-2-butyl-benzimidazole l-(N-methyl-ethanolaminomethyl)-2-methylbenzi.midazole N,N-bis(l'-benzotriazolylmethyl)ethoxyethoxypropylamine N,N-bis(l'-benzimidazolylmethyl)oleylamine N,N-bis(l'-benztriazolylmethyl)palmitolylamine N,N-bis(l'-benzotriazolylmethyl)allylamine N,N'-bis(5-a,a'-dimethylbenzyl-1-benzotriazolylmethyl) dodecylamine . ' - - . . . - . .
,~ . ': , :

1~77~47 l-(di-n-butylaminomethyl)-5-(a,a'-dimethylbenzyl)-benzotriazole The present invention also provides a process of producing a compound of formula I comprising reacting a compound having the formula:-~ / III

wherein ~ has its previous significance, with formaldehyde andwith an amine having the formula:-< IV

wherein Rl and R2 have their previous significance.

Compounds of formula III which are suitable starting-materials for use in the process of the present invention include benzo-triazole, benzimidazole and the compounds described and claimed in British Patent Specification 1,065,995 (5-alkyl benzotriazoles).
Preferably, however, compound III is benzotriazole itself.

The formaldehyde reactant is convenien~ly used in the commer-cially-available forms i.e. formalin or paraformaldehyde.

Examples of suitable amine compounds of formula IV are primary amines of formula R1~2 wherein Rl has its previous significance, : :. : . , . .................. :

: . ~ : .. , 1~)770~7 and secondary amines of formula R
R /

wherein Rl and R2 have their previous significance.

The relative proportions of the compound of formula III and IV, and formaldehyde can vary according to whether the amine of formula IV is a primary or secondary amine.
Wnlen the amine of formula IV is a primary amine, the molar ratio of compound III: formaldehyde: amine IV may be substantially either 2.0:2.0:1.0 or 1.0:1.0:1.0 and when amine IV is a secon-dary amine the molar ratio of compound III: formaldehyde: amine IV is preferably substantially 1.0:1.0:1Ø

The process of the present invention is conveniently effected by heating all the reactants together at an elevated temperature, for instance a temperature within the range of from 50 to 120C.
If desired, the compound of formula III and formaldehyde may first be reacted together to produce the corresponding N-methylol compound, prior to reaction with the amine of formula IV.

The Mannich base compounds of formula I and 1~ have been found to combine excellent metal passivation with high solubility in a wide range of functional fluids.

Accordingly, the present invention also provides a composition comprising a functional fluid and as metal passivator, a passi-, : . . . :
- ~ . ,........ -10770~7 vating amount of a compound of formula I or I~ as hereinbefore d f- d e lne .

Preferably, the composition contains from 0~001% to 5% by weight of the compound of formula I or IA based on the total weight of the composition.

~xamples of functional fluids useful in the composition of the invention are lubricants having a mineral oil or synthetic car-boxylic ester base, hydraulic fluids based on mineral oils, phosphate esters, aqueous polyglycol/polyglycol ether mixtures, glycol systems, oil-in-water and other water-in-oil emulsions and metal-working fluids having as their base mineral oils or aqueous systems, as well as aqueous glycol anti-freeze compo~
sitions .

Of particular interest in this invention, are those functional fluids which have a water base, e.g. aqueous-based anti-freeze, hydraulic and metal-working fluids. For use in this type of water-based f-1nctional fluid, those compounds of formula I
are preferred which bear a polar substituent on the nitrogen atom of the heterocyclic ring.

When the composition of the invention comprises an aqueous-based functional fluid, the substituents Rl and R2 in the com-pounds of formula I are preferably the same and at least one, and preferably each, is a residue of for~lula R30~(alkylene)0]x (alkylene) - wherein R3 has its previous significance, or R3 .. - .:. : ~ .
. ..

:-; ~

10771~7 is preferably H ancl X is zero.

On the other hand, when the composition of the present invention comprises an oil-based functional fluid, then the compounds of formula IA are the preferred metal passivators or compounds of formula I, wherein Rl and R2 are each a non-polar group such as alkenyl or cyanoalkyl. Especially preferred for this type of fluids are those compounds of formula IA, ~7herein R4 and R5 each are alkyl having from 1 to 12 carbon atoms.

Depending on the nature of the functional fluid the composition of the invention preferably contains one or more co-additives.

Examples of such co-additives suitable in non-aqueous functional fluids are antioxidants, further metal passivators, rust inhi-bitors, viscosity index improvers, pour-point depressant, dis-persants, detergents, extreme pressure and anti-wear additives.

Examples of Antioxidants are:-a) Alkylated and non-alkylated aromatic amines and mixtures thereof e.g. dioctyldiphenylamine; mono-t-octylphenyl-and ~-naphthylamines; dioctylphenothiazine; phenyl---naphthylamine: N,N'-di-sec-butyl p-phenylenediamine.

b) Hindered phenols e.g. 2,6-ditertiarybutyl-p-cresol;
4,4'-bis-(2,6 diisopropylphenol); 2,4,6-triisopropyl phenol; 2,2'-thio-bis-(4-methyl-6-tertbutylphenol) , :

c) Alkyl, aryl or alkaryl phosphites e.g. triphenylphosphite;
trinonylphosphite; diphenyldecylphosphite.

d) Esters of thiodipropionic acid e.g. dilaurylthiodipropionate e) Salts of carbamic and dithiophosphoric acids e.g. antimony diamyldithiocarbamate, zinc diamyldithiophosphate.

f) Metal salts, complexes of organic chelatine agents e.g.
copper bis (trifluoroacetonates), copper phthalocyanide, tributyl ester of EDTA, mono sodium salt.

g) Free radical antioxidants and their precursors e.g. nitro xides etc.

h) Combinations of two or more antioxidants from any of the above sections i.e. an alkylated amine and a hindered phenol.

Examples of Metal Passivators are:-a) for copper e.g. benzotriazole, 5,5'-methylene-bisbenzo-triazole, 4,5,6,7-tetrahydrobenzenetriazole, 2,5-di-mercaptothiadiazole, salicylidenepropylenediamine, salt of salicylalaminoguanidine; quinizarin etc.

b) for magnesium e.g. pyridylamines c) for lead e.g. sebacic acid, propylgallate and quinazari d) combinations of two or more of the above additives.

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Examples of Rust Inhibitors are:-a) Organic acids, and their esters, metal salts, anhydr;dese.g. N-oleoyl sarcosine, sorbitan mono-oleate, lead naphthenate, dodecenylsuccinic anhydride.

b) Nitrogen containing materials e.g.

i) Primary, secondary or tertiary aliphatic or cycloali-phatic amines and amine salts of organic and inorganic acids e.g. morpholine, stearyl amine, triethanolamine caprylate.

ii~ heterocyclic compounds e.g. imidazolines, oxazolines c) Phosphorus containing materials e.g. inorganic phosphates, phosphonic acids, amine phosphates.

-d) Sulphur containing materials e.g. barium dinonylnaphthalene sulphonates.

e) Combinations of two or more of the above additives.

Examples of Viscosity Index Improvers/Pour Point Depressants are:-e.g. polyacrylates, polybutenes, polyvinyl pyrrolidones.Examples of Dispersant/Detergents are:-e.g. metal sulphonates (Ca, Ba, Mg) and phenates, poly-butenyl succinimides.

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Examples of Extreme Pressure/Ant;wear ~dditives are:-sulphur and/or phosphorus and/or halogen containing materials e.g. sulphurised sperm oil, tritolyl-phosphate, chlorinated paraffins.
Examples of co-additives suitable for use in aqueous based products and/or glycol-glycol ether include antioxidants, corrosion and rust-inhibitors, metal passivators extreme pressure/
anti-wear additives, biocides, buffering agents and anti-foams.

Examples of antioxidants are: 2,6-ditertiarybutyl-p-cresol and phenyl-~-naphthylamine.

Examples of corrosion and rust inhibitors are:
sodium nitrite, sodium ben20ate, morpholine, amine soaps e.g.
triethanolamine sebacate, triethanolamine phosphate; disodium hydrogen phosphate, disodium sebacate, arylsulphonamido-carboxylic acid esters.

Examples of metal passivators are:
benæotriazole and sodium mercaptobenzothiazole.
Examples of extreme pressure/anit-wear additives are:
chlorinated paraffins; sulphurised sperm oil; sulphurised olefins, ethoxylated partial esters and polyglycols.

Examples of buffering agents are:
Borax and triethanolamine Examples of biocides are:

2,4,5-trichlorophenol; sodium salt of 2,2'-dihydroxy-5,5'-di-~, . . . ...
- .~
.. .. . . .

iO7704'7 chlorodiphenyl methane; and sodium salt of orthophenylphenol.
Examples of an antifoam are silicones.

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: -, ... , . . -1~)77047 Examples 1 to 14 All products were prepared by the same general method which is described below for Marmich bases from secondary amines. Mannich bases prepared from primary amines utilise half the molar quantity of amine.

23.82 parts of benzotriazole and 21.03 parts of a diethanolamine were mixed with 75 parts of ethanol and 6.0 parts of formalde-hyde added as a 36% aqueous solution. The mixture was heated to boiling and reflux conditions maintained for 8 hours (higher mol. wt. amines required a reaction time of up to 16 hours to effect satisfactory yields). After cooling, the solvent was removed under water pump vacuum and the remaining product azeo-troped with 3 x 50 parts of ethanol also under water pump vacuum.
In this way, l-diethanolaminomethyl benzo~riazole was obtained in 80% yield.

Where solid products were obtained, recrystallisation was best effected from ethyl acetate.

The products are essentially l-N-substituted though there is evidence from proton n.m.r. spectroscopy that some 2-N-substi-tution has taken place and is present to varying extents (up to 20%) in the products.

Using the same procedure, various other compounds of formula I
or IA were produced. The details of these further Examples are set out in the following Tables 1, 2 and 3.

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Examples 15 to 22 A sample of bright copper 7.62 cm x 1.27 cm x 0.16 cm was totally immersed in 50 milli].itres of aromatic spindl.e oil containing 50 parts per million of elemental sulphur and 0.05%
by weight of the product of Example 5, and subjected to the copper strip corrosion test (American Standard Test Method D -130) for 3 hours at 100C.

At the end of the test, the strip was removed from the oil, washed and dried and examined visually for corrosion.

In the following Tabel 4, the ASTM ratings are given for this experiment, and also for experiments using the products of Examples 6, 7, 8, 9, 10, 11 and 12, respectively. An ASTM
rating of 4 indicates heavy ta.n~ishing while a rating of 1 in-dicates only slight tan~ishing.

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Example ! Active In~redient I AST~IS ratin~ i A ._~
¦ Product of Example 5 ¦ 1b 1 16 ~ Product of Example 6 ¦ 2c (solubiIity¦
. I < 0.05 w/w) . . . _. _ 17 ¦ Product oI` Example 7 j 1b . _ _ 18 ~ Product of Example 8 ¦ lb 19 ¦ Produc' of Example 9 ¦ 1b 20 ¦ Product of Example 10 ~ 1b . _ ., 21 ~ Product Or Example 11 ~ 1b 22 ¦ Product of Example 12 ¦ 1b ¦

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The corrosion inhibiting properties of the solution are evaluated on the basis of weight losses incurred by the metal specimens.

The apparatus used is shown in the attached Figure 1 and is as follows:-1000 ml. "culture vessel"
multi socket flange lid water cooled reflux condenser to fit flange lid gas distribution tube with sintered head of porosity grade no. 2 adapted to fit one socket of flange lid.
Flowmeter suitable for controlling the aeration rate to 100_ 15 ml. per minute Thermometer range - 5 - 105C adapted to fit on socket of flange lid cylinder of air water bath capable of maintaining a temperature of 82 + 2C
Metal plate adapted to fit water bath so that 6 culture vessels may be accommodated.
The metal specimens (50 mm x 25 mm with central 6 mm hole) were as follows:-- ' ,, . ~ ': .,............ , ... ~ ,.

1) Steel U.S. SAE 1020 cold-rolled steel stock 2) Copper Type ETP or STP of U.S. Standard specifi-cation for copper sheet, plate or rolled bar AS~I
B 152, SAE 71 cold-rolled steel stock.

3) brass Alloy No. 8 of U.S. standard specification for brass plate, sheet, strip and rolled bar ASTM B 36, SAE 70C.

4) solder Alloy grade 30A or 30B of U.S. ASTM B 32

5) cast aluminium Alloy SC 64C of US ASTM B 179, SAE 329

6) cast iron Alloy No. 120 of US ASTM 159 SAE 120 All metal specimens were vigorously scrubbed with pumice and a moist bristle brush, rinsed in cold water then acetone and dried and weighed.

The specimens were assembled on a brass machine screw covered with thin walled insulating tubing a diameter small enough to slip easily through the central hole in the specimens. They were separated from each other by cylindrical spacers 5 mm. long, 11 mm. outside diameter, 6mm. inside di.~meter. At each end of the assembly there was a brass "leg" 50mm. by 25mm. cut from 1.5mm.

. . : -:-.,.; . ~

107704~

brass sheet and with a hole 6mm. in diameter off centre towards one end of the brass piece, orientated with their long axis in the same direction as the long axis of the specimen (see figure 1).

The specimens and legs were assembled in the following order (see figure 1)- Brass "leg", copper, solder, brass, steel, cast iron, ca~t aluminium, brass "leg". The spacers between the brass "legs" and the adjacent specimens and between the brass and steel specimens were of an insulating material, those between the brass, solder and copper specimens were of brass and those between the steel, aluminium and iron specimens were of steel.

The assembly of "legs" spacers and specimens was tightened to-gether by means of a brass nut so as to ensure that the three specimens in each section were in good electrical contact with each other.

An antifreeze formulation was then made up as follows:-monoethylene glycol 92.8% by weight triethanolamine 2.9% by weight phosphoric acid (s.g.1.75)1.1% by weight compound of Example 1 0.2% by weight borax 3.0% by weight One part by weight of this antifreeze composition was then di-luted with 2 parts of water.

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The diluted antifreeze (750 ml.) was placed in the vessel as shown in Figure 1. The vessel was irrmersed in a water bath at 82 ~ 2C. an the aeration rate was adjusted to 100 ~- 15 ml.
per minute.

The test was continued for 336 hours (2 weeks).
At the end of the test, the specirnen assembly was removed and dismantled. The individual metal specimens were washed in running water whilst brushing to remove loosely-held corrosion products. More tenacious products were removed as follows:-iron and steelThe specimen was dipped for 1 minute in 50% HCl solution con-taining 1% hexamine.

copper and brass The specimen was immersed in 30% solution of HCl for 30 seconds.

Alumini-~ r The specimen was dipped for 5 minutes in a solution containing 2% chromic acid and 5% H3P04, which was maintained at 80C.

solder The specimen was immersed in a boiling 1% acetic acid solution for S minutes.

Final cleaning of all specimens was carried out by scrubbing with a moist brush. After thoroughly cleaning, the specimens were rinsed in acetone, dried and weighed.

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Specimens are sa;d to have passed this test if the corrosion loss is lower than the following losses:-steel 2,0 mg./sq, in cast iron 2.0 mg./sq. in solder 4.0 mg./sq. in copper 2.0 mg./sq. in brass 2,0 mg./sq. in cast aluminium 7.0 mg./sq. in The results obtained are set out in Table 5 which also includes,for the purpose of comparison, data relating to tests using benzotriazole or 5-methyl benzotriazole, respectively, as the active ingredient.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A compound having the formula:- I

wherein X is N or CR wherein R is hydrogen or alkyl having from 1 to 4 carbon atoms; A is a benzene or naphthalene residue, each unsubstituted or substituted with one or more alkyl residues having from 1 to 12 carbon atoms or aralkyl residues having from 7 to 9 carbon atoms; R1 and R2 are the same or different and each is a residue of formula R30[(alkylene)O]x (alkylene)- wherein R3 is hydrogen or an alkyl residue having from 1 to 20 carbon atoms, "alkylene" is a straight- or branched chain alkylene residue having 2 or 3 carbon atoms and x is 0, 1, 2, 3 or 4; an alkenyl residue having from 2 to 20 carbon atoms or a cyanoalkyl residue having from 2 to 5 carbon atoms; or R1 has its previous significance and R2 is hydrogen, alkyl having from 1 to 20 carbon atoms, aryl having from 6 to 10 carbon atoms, cycloalkyl having from 5 to 12 carbon atoms, aralkyl having from 7 to 9 carbon atoms, or a residue of formula:- II

wherein A and X have their previous significance.

2. A compound as claimed in claim 1 wherein X is N and A
is a benzene residue.

3. A compound as claimed in claim 1 or 2 wherein the sub-stituent on the N atom constitutes a polar function.

4. A compound as claimed in claim 1 wherein at least one of R1 and R2 is a residue of formula R3O[(alkylene)O]x-alkylene wherein R3 and x are as defined in claim 1.

5. A compound as claimed in claim 4 wherein R3 is H and x is O.

6. A compound as claimed in claim 1 wherein A is an unsubstituted benzene residue or a benzene residue substituted by a methyl or dimethylbenzyl residue and wherein R1 and R2 are the same or different and each is a R3O[(alkylene)O]x alkylene residue, or R1 is such a residue and R2 is hydrogen or a 1-4C alkyl residue and R3 is hydrogen or 1-4C alkyl residue and x is O.

7. A compound having the formula:- IA

wherein X is as defined in claim 1, R4 and R5 are the same or different and each is alkyl having from 1 to 20 carbon atoms, aryl having from 6 to 10 carbon atoms, cycloalkyl having from 5 to 12 carbon atoms, or aralkyl having from 7 to 9 carbon atoms, and R6 is an aralkyl residue having from 7 to 9 carbon atoms.

8. A compound as claimed in claim 7 wherein R6 is an .alpha.,.alpha.-dimethylbenzyl residue.

9. A compound as claimed in claim 7 wherein X is N.

10. A compound as claimed in any of claims 7 to 9 wherein R3 and R4 are the same or different and each is an alkyl residue having from 1 to 12 carbon atoms.

11. A process of producing a compound of formula I or IA
comprising reacting a compound having the formula:- III

wherein A is as defined in claim 1, with formaldehyde and with an amine having the formula IV

wherein R1 and R2 are as defined in claim 1.

12. A process as claimed in claim 11 wherein the compound of formula III is benzotriazole.

13. A composition comprising a functional fluid and, as metal passivator, a passivating amount of a compound of formula I as claimed in claim 1.

14. A composition as claimed in claim 13 wherein the amount of the compound of formula I is from 0.001% to 5% by weight based on the total weight of the composition.

15. A composition as claimed in claim 13 wherein the functional fluid is a lubricant having a mineral oil or synthetic carboxylic ester base, a hydraulic fluid based on a mineral oil, a phosphate ester, a polyglycol/polyglycol ether mixture or an aqueous glycol system, oil-in-water and water-in-oil emulsions, a metal-working fluid based on a mineral oil or an aqueous system or an aqueous glycol anti-freeze composition.

16. A composition as claimed in claim 13 wherein the functional fluid is water-based and the compound of formula I
bears a polar substituent on the nitrogen atom of the hetero-cyclic ring.

17. A composition as claimed in claim 16 wherein at least one of R1 and R2 is a residue of formula R3O[(alkylene)O]x-alkylene wherein R3 and x are as defined in claim 1.

18. A composition as claimed in claim 17 wherein R3 is H
and x is O.

19. A composition as claimed in claim 16 wherein A is an unsubstituted benzene residue or a benzene residue substituted by a methyl or dimethylbenzyl residue and wherein R1 and R2 are the same or different and each is a R3O[(alkylene)O]xalkylene residue, or R1 is such a residue and R2 is hydrogen or a 1-4C
alkyl residue and R3 is hydrogen or a 1-4C alkyl residue and x is O.

20. A composition as claimed in any of claims 13 to 15 wherein the functional fluid is oil-based and substituents R1 and R2 in the compound of formula I are each an alkenyl or cyanoalkenyl group.

21. A composition comprising a functional fluid and, as metal passivator, a passivating amount of a compound of formula IA as defined in claim 7.

22. A composition as claimed in claim 21 wherein the amount of the compound of formula IA is from 0.001% to 5% by weight, based on the total weight of the composition.

23. A composition as claimed in claim 21 or 22 wherein the functional fluid is a lubricant having a mineral oil or synthetic carboxylic ester base, a hydraulic fluid based on a mineral oil, a phosphate ester, a polyglycol/polyglycol ether mixture, an aqueous glycol system, an oil-in-water or a water-in-oil emulsion, a metal-working fluid based on a mineral oil or an aqueous system or an aqueous glycol anti-freeze composition.

24. A composition as claimed in claim 21 wherein the functional fluid is oil-based.

25. A composition as claimed in claim 24 wherein each of R4 and R5 is an alkyl residue having from 1 to 12 carbon atoms.