Note: Descriptions are shown in the official language in which they were submitted.
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.. - .. . ............
--''':' '':,-
:' . ~ ' .' :.
. ....... . .. .
: . . . ` ,. ~, :
~ .. ; :
1077047
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 ~
CH2 -
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 ~
R5
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.
~ . ,, ,. : .
;:, ' ~ .
1077047
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
- 6 -
. '
- - . . . - . .
,~ . ': , :
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
R2
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,
-- 7 --
: :. : . , . .................. :
: . ~ : .. ,
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)
- 10 -
, :
1077047
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.
,~ . .... ;, , .. .. :
: : . ~: . ::
. . - . :
.. ,; , . . ~ . :
. . .
1077047
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.
- 12 -
.
. ,. , ~.
- .
.. .. .
- : . ,
.
. . . .:: .
.. : .: ~ :
1077047
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-
- 13 -
~, . . . ...
- .~
.. .. . . .
iO7704'7
chlorodiphenyl methane; and sodium salt of orthophenylphenol.
Examples of an antifoam are silicones.
- 14 -
~. . . ........ .' ~
.
.. . . .
:,:. . . : .: ~ -
:, , . . ., ~
... ~ . . . :
: -, ... , . . -
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.
- 15 -
? ~ ;
,~
10~77047
_ _ __
~ ~- O a) C~ ~ ~ O ~
',~; ~--~ a~ ~ ~ ~ N ~ 0~) U~ t--
~ t- ~- l--~- O O J ~ 00 cO
,_ C\l tU ~1 ~1C\l t~l C\l ~l t`~ ~ r-l ~1
_
u) o~ ~o ~ ~- o a~ ~ ~ ~ ~ G~
H 1--CO C\~ ~ oO ~t `, ;1- ~\I ;i-
U~ ~ . .. . . . . . . .
~ ~ ~ _ ~ ~ 1-~ ~t-
¢ _ __
¢ ~ 0~ ~ ~ O C~ O ~ ~ ~ :
V ~ ~ ~ ~ ~ ~ ~ 0
~ ~i ~i ~ ~ .... 00 0~ ~ ~
u~ u~ ~O ~O ~ u~ ~ ~O ~ ~ l- l-
_ _ ., ~ ~ ~14 ~ ~_
V V V ~
o o O O
~ . . ~ O~ 00 . ~
t~ ~ ~ ~ ol ol l ol o l .
\ / . . ~`I O . C?~ t~l
~ / ~ ~ u~ O~ ~ ~1
X\ Z
.
a~ ,s ~r~ r~ ,S ~
--~ ~ ~ ~ H ~1 h ,1 ,~ ,1 v
6S O O O O :.~ O ~( rl ~
h u7 u~ u) , ~n O O~: H
_ __ _ a~ ~
,_ ~ 6S
~ O ~
'~ 1 O ~l U~ ~1 ~1 r~ O
~: ,_1 cO ~ t~ ~o 1-- ~h ~$
.~ :~ ~s.3 o
~ ~U
O O V V11 11
6S ~ ~\l ~ ~~ ~4
'CS ~ V V V V *
~ 'P~ V~ V ~ ~ X~ V
U~ _ l l l l l
E~ c~l c~l
O O O O V V'
~1 ~I ~\l ~I t~l ll ll
U~ 1:~ V V V V X V
. ~ ~ V ~ ~ X~
.
s~ . x z m :z m ::c v
. _ .
l ~
S .
~1 O ~1 C~l ~ J u~ ~S)
~S _ _ __
- 16 -
.
.. ... ~ .
.. .
: .:: :~: : : . l
1077(~47
_ _ ~ _ C\!3 CO (r~ t~ O~D ~ .
U~3 ~~ C G~ U~ ~ t~
~; CO CO O O ~ ~ ~ CO CO
_ r- . C\~ ~ C~ l r- ~
~ co~ O~c ~co ~ c~ a~
> ._ CO Cr~ ~ U~1~ ~D u~u~
(;~ >~
O~ r- O U~ ~ ~! 3 ~t) ; CO
~ t\l ~ G~ ~ r- ~ U~ O ~
V ~ \1 C~ . C~l ~ O 3 ~ .
~ ~ r-~ ~D ~,~
~' . ~i
,_ __ ~ __ __ ~ . ~ ~ ._~ , ~ .
rl . V V V OrV ~
h . o r o o e
h l l 3 r CO O
E ~ ~ . _ . _ td
~ 1`~ ~ ~ ~ ~ ~ ,~' .~
~ \ / ~X h O rO *
a I _ . I _ u~ ~ U~ O~ __
l ~ .-
c\l _~
v ,1o u~ ~o ~I ~ co
r-l ~~ ~ I_ CO ~ ~
_ _ ..
1_~ ~ X~
V ~ OV O
1~ It ll ~
~o $o v ~ ~ X~
K~ r- ~ ~ V V
V V V V
_ l l l l _l l
X ~ ~ _~ _ ~; ' "'^'
E r- co ~ O r
V _
- 17 -
~' ,' ; ' :
, ., .: : . : -
:: . - ~ ,:: ~`'; -
, : : ,:, , . :
1077~7
~ o G~ r
co co 00 G~
:~; ~ ~ oo co
G~ _ _
U~ ~ ~
~rl ~ ~0
(~ . ~ ~-
G~ ) O ~-
00 0~0
. ~ ~0~ ~
_ ~ .~ ~
Pl
~d
p l l .
~ e
'0~ O
R
.~ .
h
Q~
.,J . ~
o ~ P~ O
~3 ~ h - h ~o
~n
~ U~ U~
U~ ,1 C~J tl~ _
E z Z a _= a
~ ~ O~ ~ ~
~ O
E ~ ~ ~ ~ ~cl o
~- _,~
o ~~
~: a R ~ h
~ ~R ¢
E .. . _ r
.
-- ~ 8 --
iO770~
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.
. .-~
:
.. .
,: .
.
1077047
-TA13TE 4
. ~
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 ¦
.
- 20 -
, : .: .. -
:: . .; . -. ., ::
:~: . -
: ~ . .: - :: -. .:
: ~ . . : - ., . , ;, ~ - . .
... . , .,, ~ . . .,
7047
Example 23
Specimens of metals typical of those which may be present in
the cooling system of an interna:L combustion engine are totally
immersed in an aerated test solution for two weeks at 82C.
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:-
- ' ,, . ~ ': .,............ ,
... ~ ,.
1077047
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.
- 22 -
. . : -
:-.,.; . ~
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.
- 23 -
.
: - ... .
- . :. : ~: , .
. i , ~ , ~ . . . : , .
:, . , ' ; . , :' ' ' ~ "'' ~
1077047
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.
- 24 -
, . . : , .
: . . . : ~ ~ . .
- ,. . . .
. : ,
; ~ - ..
.. : ., :. ,-. :
. . :, . ; ~:
.. : . :. .. ::
1077047
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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