U.S. patent application number 10/507719 was filed with the patent office on 2005-08-04 for oil composition and method of detecting a marker in an oil composition.
Invention is credited to Lunt, Nigel Edmund, Southby, Mark Clift, Wetton, Robert John, Woollaston, Emma Jayne.
Application Number | 20050170976 10/507719 |
Document ID | / |
Family ID | 27838134 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050170976 |
Kind Code |
A1 |
Lunt, Nigel Edmund ; et
al. |
August 4, 2005 |
Oil composition and method of detecting a marker in an oil
composition
Abstract
Oil composition is provided containing a major amount of a
natural and/or synthetic base oil and, as a marking substance, a
detectable level of one or more compounds of formula IV compound
supported thereon, such that the marking substance gives a colour
reaction 1 A method for detecting the presence of a marking
substance in an oil composition is provided, wherein the oil
composition is contacted with a test strip having an acidic upon
contact with the test strip.
Inventors: |
Lunt, Nigel Edmund;
(Cheshire, GB) ; Southby, Mark Clift; (Cheshire,
GB) ; Wetton, Robert John; (Cheshire, GB) ;
Woollaston, Emma Jayne; (Manchester, GB) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
|
Family ID: |
27838134 |
Appl. No.: |
10/507719 |
Filed: |
March 28, 2005 |
PCT Filed: |
March 14, 2003 |
PCT NO: |
PCT/EP03/02823 |
Current U.S.
Class: |
508/184 ;
44/328 |
Current CPC
Class: |
C10L 1/003 20130101;
C10L 1/226 20130101; C10M 171/007 20130101; G01N 33/2882
20130101 |
Class at
Publication: |
508/184 ;
044/328 |
International
Class: |
C10M 133/28; C10L
001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2002 |
EP |
02251890.6 |
Claims
1. An oil composition comprising at least one compound of formula
IV; 7wherein R.sup.1-R.sup.9 are the same or different and are
independently chosen from hydrogen, C.sub.1-5 alkyl and other
non-conjugated groups; R.sup.10 is chosen from hydrogen and
C.sub.1-15 alky; and R.sup.1 is a conjugated group, and a natural
and/or synthetic base oil, said compounds of formula IV useful to
give a colour reaction under action of an aqueous solution of
protic acid.
2. A method for detecting the presence of a marking substance in an
oil composition which comprises a major amount of a natural and/or
synthetic base oil and a detectable level of a marling substance,
wherein the oil composition is contacted with a test strip
comprising an acidic compound supported thereon, such that said
marking substance gives a colour reaction upon contact with the
test strip, wherein the oil composition comprises a major amount of
a natural and/or synthetic base oil and, as a marking substance, a
detectable level of at least one compound of formula IV 8wherein
R.sup.1-R.sup.9 are the same or different and are independently
chosen from hydrogen, C.sub.1-15 alkyl and other non-conjugated
groups; R.sup.10 is chosen from hydrogen and C.sub.1-15 alkyl; and
R.sup.11 is a conjugated group.
3. The method of claim 2 wherein the oil composition comprises, as
a marking substance, a detectable level of at least one compounds
of formula V 9wherein R.sup.1-R.sup.9 are the same or different and
are independently chosen from hydrogen, C.sub.1-15 alkyl and other
non-conjugated groups; R.sup.10 is chosen from hydrogen and
C.sub.1-15 alkyl; and R.sup.12-R.sup.16 are the same or different
and are independently chosen from hydrogen, C.sub.1-5 alkyl and
other non-conjugated groups.
4. The method of claim 2 wherein the oil composition comprises an
amount in the range of from 1 ppmw to 400 ppmw of compounds of
formulae IV based on the total weight of the oil composition.
5. The method claim 2 wherein the oil composition is a fuel oil
composition.
6. The method claim 2 wherein the oil composition is a lubricating
oil composition.
7. The method claim 2 wherein the acidic compound is adsorbed on a
carrier prior to being supported on the test strip.
8. The method claim 2 wherein the acidic compound is selected from
the group consisting of trichloroacetic acid, hydrochloric acid,
sulphuric acid, 4-dodecylbenzene sulphonic acid (DBSA), picric acid
and benzene sulphonic acid.
9. The method of claim 3, wherein the oil composition comprises an
amount in the range of from 1 pDmw to 400 ppmw of compounds of
formula V based on the total weight of the oil composition.
10. The method of claim 3, wherein the acidic compound is adsorbed
on a carrier prior to being supported on the test strip.
11. The method of claim 8, wherein the acidic compound is adsorbed
on a carrier prior to being supported on the test strip.
Description
[0001] The present invention relates to an oil composition and a
method of detecting a marker in an oil composition.
[0002] Adulteration, counterfeiting and other fraudulent activities
in relation to oil compositions has been a concern in industry in
recent years.
[0003] Such activities can result in lost revenue and lack of
customer confidence.
[0004] Strategies to combat such fraudulent activities include the
addition of dyes and/or covert chemical compounds (markers) to the
oil composition.
[0005] The use of a dye or marker allows the authenticity of an oil
composition to be assessed. This has many benefits for the oil
composition manufacturer, including protection of brand name,
increased customer confidence and tracking of product at any stage
in the production and distribution chain.
[0006] FR-A-1495064 discloses a process for the colouration of
oils, fats, waxes, greases, lacquers, solvents and plastics which
comprises adding thereto a dyestuff which is an aminoazo compound
free from hydrophilic groups of formula Ph--N.dbd.N--Ph--NR.sub.1R
as described therein.
[0007] J. Chem. Soc. Faraday Trans., vol. 86, no. 20, 1990, pp
3447-3453 describes cyclohexane solutions of a number of different
indicators of varying chemistries. Amongst the indicators disclosed
is 4-(phenylazo)diphenylamine (PADA).
[0008] In combating fraudulent activity, rather than using a simple
dye, it is often desirable to employ a so-called silent marker,
that is to say, a marker which imparts substantially no colour to
an oil composition at the level at which it is used, but which can
be easily detected, qualitatively or quantitatively, in the tagged
oil composition by performing chemical and/or physical tests
thereon it is of ten preferable that such testing can be conducted
in the field and markers are therefore usually detected by a
reactive extraction method. For example, U.S. Pat. No. 5,490,872
discloses markers which are detectable by extraction from petroleum
fuel with a dilute acidic solution such as a 10% hydrochloric acid
or formic acid solution.
[0009] U.S. Pat. No. 5,560,855 describes a method for tagging and
identifying refrigeration lubricants using silent markers.
Identification relies upon a reactive extraction method.
[0010] U.S. Pat. No. 5,145,573 describes marked mineral oils
containing, as marking substances, azo dyes of formula (I), 2
[0011] in which n is equal to 0 or 1, R.sup.14 and R.sup.20 are the
same or different and independently denote hydrogen or
C.sub.1-C.sub.8 alkyl optionally substituted by hydroxy and
optionally interrupted by one or two oxygen atoms, R.sup.15 and
R.sup.18 are the same or different and independently denote
hydrogen, C.sub.1-C.sub.4 alkyl or the radical NR.sup.13R.sup.14,
in which R.sup.13 and R.sup.14 have the above meanings, R.sup.16,
R.sup.17 and R.sup.19 are the same or different and independently
denote hydrogen or C.sub.1-C.sub.4 alkyl.
[0012] Markers of formula (I) have dye characteristics and
additionally undergo a bathochromic shift of their absorption
maximum and an increase in absorbance when there is added thereto a
protogenic acid.
[0013] The marked mineral oil of U.S. Pat. No. 5,145,573 is tested
by shaking a sample of the oil with a detector reagent comprising a
protogenic acid, separating the two phases and comparing
calorimetrically the coloured phase with a solution of known
concentration, so that the dye content can be assessed
quantitatively.
[0014] U.S. Pat. No. 5,182,372 discloses mineral oils containing
one or more azo dyes of formula (II), 3
[0015] in which R.sup.1, R.sup.2 and R.sup.3 are the same or
different and independently denote hydrogen, C.sub.1-C.sub.4 alkyl
or C.sub.1-C.sub.4 alkoxy, R.sup.4 denotes C.sub.1-C.sub.6 alkyl
and R.sup.5 denotes C.sub.2-C.sub.8 alkyl which is substituted by
hydroxy and may be interrupted by 1, 2 or 3 oxygen atoms, provided
that the total number of carbon atoms in the radicals R.sup.4 and
R.sup.5 is at least 5.
[0016] The indication of the dyes of formula (II) in said mineral
oils is achieved by testing the oil with aqueous acid to obtain a
colour reaction.
[0017] U.S. Pat. No. 5,827,332 describes hydrocarbons containing,
as pH-dependent markers, azo dyes of formula (III), 4
[0018] where the ring A may be benzofused, n is 0 or 1, R.sup.1 is
hydrogen or C.sub.1-C.sub.15 alkyl which may be interrupted by from
1 to 4 ether oxygen atoms, R.sup.2 is C.sub.1-C.sub.15 alkyl which
may be interrupted by from 1 to 4 ether oxygen atoms, or a radical
of the formula L-NX.sup.1X.sup.2, where L is C.sub.2-C.sub.8
alkylene and X.sup.1 and X.sup.2 independently of one another are
each C.sub.1-C.sub.6 alkyl or, together with the nitrogen atom
linking them, form a 5-membered or 6-membered saturated
heterocyclic radical which may furthermore contain an oxygen atom
in the ring, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7
independently of one another are each hydrogen, C.sub.1-C.sub.15
alkyl or C.sub.1-C.sub.15 alkoxy and R.sup.8 is hydrogen,
C.sub.1-C.sub.15 alkyl, C.sub.1-C.sub.15 alkoxy, cyano, nitro or a
radical of the formula COOX.sup.3, where X.sup.3 is hydrogen,
C.sub.1-C.sub.15 alkyl which may be interrupted by from 1 to 4
ether oxygen atoms, or is a radical of the formula
L-NX.sup.1X.sup.2, where L, X.sup.1 and X.sup.2 each have the above
meanings.
[0019] Azo dyes of formula (III) are said to give a colour
reaction, i.e. a colour change, accompanied by a deepening of
colour, under action of a protic acid.
[0020] Testing of the tagged hydrocarbon is said to occur by
extracting an amount thereof with an amount of aqueous alcoholic or
alcoholic solution of the protic acid.
[0021] Reactive extraction methods present a number of problems.
Said methods often give rise to handling difficulties in the field
as they involve reagents which may leak or spill, and which are
often highly concentrated acidic solutions. Furthermore, testing is
wasteful as sampled oils are contaminated and cannot be returned to
the bulk oil. Thus, such methods also present disposal problems for
the reagents used and the samples tested.
[0022] A further problem is that extractive testing methods require
a clear, homogeneous phase separation, which can often be a slow
process.
[0023] An alternative method that has been suggested in
EP-A-0887644 is to draw a fuel composition comprising an acid- or
base-extractable marker through an ion-exchange resin column which
is acidic or basic, as the case may be.
[0024] It is highly desirable to develop further alternatives for
testing marked oil compositions which not only avoid the problems
presented by reactive extraction methods, but which are also
inexpensive, fast, and simple in that they require no special
equipment or skills in order to perform and which can therefore be
carried out in the field.
[0025] EP-A-0311790 describes a process for marking a mineral oil
product wherein a dye precursor is used as a marking agent therein,
which marking agent can be detected by a number of methods
including dipping a test strip containing an acidic agent into the
marked mineral oil product.
[0026] It is particularly attractive to be able to develop a method
which can be carried out by the end customer at the point of sale,
thereby increasing customer confidence in the authenticity of the
product that they are purchasing.
[0027] A further difficulty in developing such a method that can be
carried out by unskilled operators is that often oil compositions
may have some inherent colouration due to the presence of certain
additives and/or contaminants therein.
[0028] For example, the aromatics content of a base oil may lead to
a yellow-orange colouration thereof and thus compositions
comprising said base oil therein may have an inherent colouration.
Such an inherent colouration may present difficulties in detecting
a marker therein when said marker undergoes a colour change upon
testing. For example, the colour change of a marker which generally
changes to from colourless/yellow to red upon action of an acid may
not be easily detected if there is a yellow-orange background
colouration to the oil composition. Such a colour change may then
only be presented as a deepening in the yellow-orange
colouration.
[0029] Thus, it is of importance to not only develop a method which
overcomes the problems of reactive extraction methods, but to also
find a marking substance that may be used in oil compositions which
gives a clear and unambiguous colour change even when the oil
composition has an inherent colouration, such that the colour
change can be detected by an unskilled operator.
[0030] There has been surprisingly found in the present invention a
simple, fast and economic method for detecting the presence of
marking substances in oil compositions which can be carried out by
unskilled operators in the field.
[0031] In addition, there has also been found in the present
invention a marking substance which gives a clear and unambiguous
colour change in an oil composition under action of an acidic
compound that can be easily detected by unskilled operators, even
when said oil composition has some inherent colouration.
[0032] The present invention provides an oil composition comprising
a major amount of a natural and/or synthetic base oil and, as a
marking substance, a detectable level of one or more compounds of
formula IV, 5
[0033] wherein R.sup.1-R.sup.9 are the same or different and are
independently chosen from hydrogen, C.sub.1-15 alkyl and other
non-conjugated groups; R.sup.10 is chosen from hydrogen and
C.sub.1-15 alkyl; and R.sup.11 is a conjugated group.
[0034] The present invention further provides a method for
detecting the presence of a marking substance in an oil composition
which comprises a major amount of a natural and/or synthetic base
oil and a detectable amount level of a marking substance, wherein
the oil composition is contacted with a test strip comprising an
acidic compound supported thereon, such that said marking substance
gives a colour reaction upon contact with the test strip.
[0035] Generally, said colour reaction will be apparent by a colour
change on the portion of the test strip which is contacted with
said oil composition.
[0036] Also provided by the present invention is a test strip
comprising an acidic compound supported thereon.
[0037] By "conjugated group" in the present invention is meant a
group, R.sup.11, which is conjugated through the adjacent nitrogen
atom to which R.sup.10 is also bonded, to the azo part of the
molecule under action of an acidic compound, thereby shifting the
value of .lambda..sub.max for the marking substance as a whole to
above 485 nm, preferably above 495 nm, provided that said group
does not increase .lambda..sub.max for the marking substance as a
whole in its basic state to wavelengths of higher than 485 nm,
preferably than 475 nm.
[0038] In a preferred embodiment, R.sup.11 is a group selected from
--CX.dbd.CYZ, wherein X is chosen from hydrogen, C.sub.1-8 alkyl,
alcohol, ether, acid, amine, aldehyde, nitro and halide, in
particular --Cl; Y is hydrogen or an ethylenically saturated or
unsaturated hydrocarbyl group containing from 1 to 6 carbon atoms;
and Z is hydrogen, C.sub.1-8 alkyl, alcohol, ether, acid, amine,
aldehyde, nitro and halide, in particular --Cl or X and Y together
form an ethylenically saturated or unsaturated bivalent group
containing 3 to 5 carbon atoms in the backbone thereof, said
bivalent group optionally containing one or more heteroatoms
therein.
[0039] R.sup.11 may contain heteroatoms and in a preferred
embodiment is selected from an optionally substituted conjugated
olefinic group containing from 2 to 8 carbon atoms in the olefin
backbone of the group, an optionally substituted aromatic group, an
optionally substituted polyaromatic group, an optionally
substituted aromatic heterocyclic group and an optionally
substituted polyaromatic heterocyclic group.
[0040] Examples of optionally substituted aromatic groups and
optionally substituted polyaromatic groups include phenyl,
naphthyl, anthracenyl, phenanthracenyl.
[0041] Examples of optionally substituted aromatic heterocyclic
groups and optionally substituted polyaromatic heterocyclic groups
include 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, furyl, thienyl,
indenyl, imidazolyl, triazolyl, oxazolyl, isoxazolyl, carbazolyl,
thiazolyl, benzothiazolyl, thiadiazolyl, pyrimidinyl, pyridyl and
pyridazinyl.
[0042] Said groups may be optionally substituted with one or more
groups such as C.sub.1-8 alkyl, alcohol, ether, acid, amine,
aldehyde, nitro and halide, in particular --Cl.
[0043] By "non-conjugated group" in the present invention is meant
a group which does not shift the value of .lambda..sub.max for the
marking substance as a whole in its basic state to wavelengths of
higher than 485 nm, preferably than 475 nm.
[0044] Non-conjugated groups that may be conveniently used include
halide, hydroxy, ether, sulphonic acid, carboxylic acid or alkenyl
groups wherein the double bond therein is not directly conjugated
to the aryl ring.
[0045] In a preferred embodiment, R.sup.1-R.sup.9 in (IV) are the
same or different and are independently chosen from hydrogen,
C.sub.1-8 alkyl and other non-conjugated groups; and R.sup.10 is
chosen from hydrogen and C.sub.1-8 alkyl.
[0046] In a preferred embodiment of the present invention, the
marking substance is one or more compounds of formula V, 6
[0047] wherein R.sup.1-R.sup.9 are the same or different and are
independently chosen from hydrogen, C.sub.1-15 alkyl and other
non-conjugated groups; R.sup.10 is chosen from hydrogen and
C.sub.1-15 alkyl; and R.sup.12-R.sup.16 are the same or different
and are independently chosen from hydrogen, C.sub.1-15 alkyl and
other non-conjugated groups.
[0048] In a preferred embodiment, R.sup.1-R.sup.9 in (V) are the
same or different and are independently chosen from hydrogen,
C.sub.1-8 alkyl and other non-conjugated groups; R.sup.10 is
independently chosen from hydrogen, C.sub.1-8 alkyl; and
R.sup.12-R.sup.16 are the same or different and are independently
chosen from hydrogen, C.sub.1-8 alkyl and other non-conjugated
groups.
[0049] A particularly preferred marking substance according to the
present invention is 4-(phenylazo)diphenylamine.
[0050] The general preparation of azo dyes by diazotization and
coupling is well known in the art (see for example, Kirk-Othmer
Encyclopaedia of Chemical Technology (3.sup.rd Edition, New York,
1978), Volume 3, pp 387-392).
[0051] The marking substances of formulae (IV) and (V) may be
conveniently prepared by methods described therein and also in
GB-B-1311374, U.S. Pat. No. 5,182,372, U.S. Pat. No. 5,827,332, or
by methods analogous thereto.
[0052] The N-mono or di-substituted anilines which may be used in
the preparation of said azo dyes are well known in the art and may
conveniently be prepared by conventional methods, for example, by
the reaction of aniline or N-monosubstituted aniline with alkyl
halide (e.g. as described in Organic Chemistry, J. McMurry,
Brooks/Cole Publishing Company, California, 1988, pp. 906-908 and
J. Am. Chem. Soc. 82, 6163 (1960)); catalytic reduction of a
Schiff's base formed from aniline and an aldehyde (e.g. as
described in Org. React. 5, 301 (1940); reaction of aniline with
the corresponding alcohol, such as phenol, in the presence of zinc
chloride (Organic Chemistry. Volume One. The Fundamental Principles
(4.sup.th Ed.), I. L. Finar, Longmans, London, 1963, page 567); and
reaction of an aldehyde or ketone with an amine (e.g. as described
in Arm. Khim. Zh. (1969), 22(8), 702-6 and Organic Chemistry, J.
McMurry, Brooks/Cole Publishing Company, California, 1988, page
677).
[0053] The oil composition according to the present invention may
conveniently comprise the marking substance in an amount in the
range of from 1 to 400 ppmw, preferably in the range of from 5 to
100 ppmw and most preferably in the range of from 10 to 30 ppmw,
based on the total weight of the oil composition.
[0054] The base oil used in the present invention is a natural or a
synthetic base oil, or a mixture thereof. Said base oil may be
conveniently used in fuel and/or lubricating oil compositions.
[0055] The amount of base oil incorporated in the oil composition
will depend upon the application in which it is intended to be
used.
[0056] In fuel oil compositions, said base oil is preferably
present in the oil composition in an amount in the range of from 60
to 99.95% wt., more preferably in an amount in the range of from 65
to 99% wt., with respect to the total weight of the oil
composition.
[0057] In lubricating oil compositions, said base oil is preferably
present in the oil composition in an amount in the range of from 60
to 99.95% wt., more preferably in an amount in the range of from 90
to 99.95% wt., with respect to the total weight of the oil
composition.
[0058] Liquid hydrocarbon fuel oils include gasolines, kerosines,
jet fuels, diesel fuels, heating oils and heavy fuel oils. Such
fuel oils may consist substantially of hydrocarbons or they may
contain blending components, such as alcohols or ethers.
[0059] Liquid hydrocarbon fuel oils of the gasoline boiling range
are typically mixtures of hydrocarbons boiling in the temperature
range from about 25.degree. C. to about 232.degree. C., comprising
mixtures of saturated hydrocarbons, olefinic hydrocarbons and
aromatic hydrocarbons.
[0060] The base fuel oil is derived from straight run gasoline,
polymer gasoline, natural gasoline, dimer and trimerized olefins,
synthetically produced aromatic hydrocarbon mixtures, from
thermally or catalytically reformed hydrocarbons, or from
catalytically cracked or thermally cracked petroleum stocks, and
mixtures of these.
[0061] The hydrocarbon composition and octane level of the base
fuel are not critical. The octane level, (R+M)/2, will generally be
above about 85 (where R is Research Octane Number and M is Motor
Octane Number).
[0062] Liquid hydrocarbon fuel oils which are middle distillate
fuel oils typically have a boiling range in the range 100.degree.
C. to 500.degree. C., e.g. 150.degree. C. to 400.degree. C.
Petroleum-derived fuel oils may comprise atmospheric distillate or
vacuum distillate, or cracked gas oil or a blend in any proportion
of straight run and thermally and/or catalytically cracked
distillates. Such fuel oils include kerosine, jet fuels, diesel
fuels, heating oils and heavy fuel oils. In a preferred embodiment,
the fuel oil is a diesel fuel.
[0063] Diesel fuels typically have initial distillation temperature
about 160.degree. C. and final distillation temperature of
290-360.degree. C., depending on fuel grade and use. Preferred
diesel fuels are low-sulphur diesel fuels.
[0064] The fuel oil composition according to the present invention
can contain further additives usually present in fuel oils, such as
anti-static agents, pipeline drag reducers, flow improvers (e.g.
ethylene/vinyl acetate copolymers or acrylate/maleic anhydride
copolymers) and wax anti-settling agents (e.g. those commercially
available under the Trade Marks "PARAFLOW" (ex Infineum
International Ltd.), "DODIWAX" (ex Clariant GmbH).
[0065] Fuel oil compositions of the present invention may contain
other additive components in addition to those already indicated.
For example, a dispersant additive, e.g. a polyolefin substituted
succinimide or succinamide of a polyamine, may be included. Such
dispersant additives are described for example in UK Patent
960,493, EP-A-147 240, EP-A-482 253, EP-A-613 938, EP-A-557 561 and
WO-A-98/42808. Such dispersant additives are preferably present in
amounts in the range of from 10 to 400 ppmw, more preferably 40 to
200 ppmw, active matter based on the fuel oil composition.
[0066] When the liquid hydrocarbon middle distillate fuel oil has a
sulphur content of 500 ppmw or less, the fuel oil composition
preferably additionally contains a lubricity enhancer in an amount
in the range from 50 to 500 ppmw based on the fuel oil composition.
Commercially available lubricity enhancers include those available
as "EC 831" and "PARADYNE (trade mark) 655" ex Infineum, "HITEC"
(trade mark) E 580 ex Ethyl Corporation and "VEKTRON" (trade mark)
6010 ex Infineum.
[0067] Further additive components which may be present include
ignition improvers (cetane improvers) (e.g. 2-ethylhexyl nitrate,
cyclohexyl nitrate, ditertiarybutyl peroxide and those disclosed in
U.S. Pat. No. 4,208,190 (at Column 2, line 27 to Column 3, line
21); anti-rust agents (e.g. that commercially sold by Rhein Chemie,
Mannheim, Germany as "RC 4801", a propane-1,2-diol semiester of
tetrapropenyl succinic acid, or polyhydric alcohol esters of a
succinic acid derivative, the succinic acid derivative having on at
least one of its alpha-carbon atoms an unsubstituted or substituted
aliphatic hydrocarbon group containing from 20 to 500 carbon atoms,
e.g. the pentaerythritol diester of polyisobutylene-substituted
succinic acid), reodorants, anti-wear additives; anti-oxidants
(e.g. phenolics such as 2,6-di-tert-butylphenol, or
phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine);
corrosion inhibitors; ashless detergents; anti-knock agents;
dehazers; spark-aiders; valve-seat protection compounds; synthetic
or mineral oil carrier fluids; anti-foaming agents and metal
deactivators. A reodorant may be included, if desired.
[0068] The concentration of the ignition improver in the fuel is
preferably in the range 0 to 600 ppmw, e.g. 300 to 500 ppmw.
Concentrations of other additives not yet specified are each
preferably in the range 0 to 20 ppmw.
[0069] The lubricant base oils that may be used in the oil
composition of the present invention, can be any base fluid which
is suitable for use in lubricating oils. The base oil can be a
natural or a synthetic lubricant base oil, or a mixture
thereof.
[0070] The natural oil can be an animal oil or vegetable oil, such
as lard oil or castor oil, or a mineral oil such as liquid
petroleum oils and solvent treated or acid treated mineral
lubricating oil of the paraffinic, naphthenic, or mixed
paraffinic/naphthenic-type which may be further refined by
hydrocracking and hydrofinishing processes and/or dewaxing.
[0071] Synthetic lubricating oils include hydrocarbon oils and
halo-substituted hydrocarbon oils such as polymerised and
interpolymerised olefins.
[0072] A suitable base oil may contain poly-alpha-olefins, such as
polydecene. Preferably, the base oil is a hydrocarbon base oil.
More preferably, the base fluid is a mineral oil which contains
less than 10% wt. of aromatic compounds, preferably less than 5%
wt., measured according to DIN 51378. It is further preferred that
the base oil contains less than 1.0% wt. of sulphur, calculated as
elemental sulphur, preferably less than 0.1% wt., measured
according to ASTM D 4045. Such mineral oils can be prepared by
severe hydroprocessing. Preferably, the lubricating oil has a
kinematic viscosity in the range of from 5 to 220 cSt at 40.degree.
C., more preferably of from 10 to 200 cSt, most preferably of from
20 to 100 cSt.
[0073] The lubricating oil composition according to the present
invention can contain further additives that are usually present in
lubricating oils, such as pour point depressants, anti-foam agents
and demulsifier. Pour point depressants generally are high
molecular weight polymers such as alkylaromatic polymers and
polymethacrylates. As anti-foam agents, silicone polymers and/or
polymethacrylates are generally used. Demulsifiers which are
generally applied are polyalkylene glycol ethers. Furthermore,
further detergents such as sulphonates and phenates, metal
deactivators, antioxidants such as phenolic compounds, diphenyl
amines and phenyl naphthyl amines, ashless anti-wear agents and/or
ashless dispersants, such as succinimides, can be present.
[0074] The oil compositions of the present invention may be
conveniently prepared by dissolving the desired amount of the
marking substance in a carrier fluid and then admixing the
resulting solution with base oil. The carrier fluid may then
optionally be removed from the oil composition by conventional
means such as distillation. Carrier fluids that may be conveniently
used include hydrocarbon, alcohol and ester solvents.
[0075] Compounds of formulae IV and V as described herein may be
used as pH-dependent marking substances in the oil compositions of
the present invention as they give a colour reaction under action
of an acidic compound.
[0076] Said acidic compound may be a protic acid and/or a Lewis
Acid. Preferably, said acidic compound is a protic acid.
[0077] The choice of acidic compound depends upon the marking
substance being tested and the method being used. In a preferred
embodiment, the pKa of the acidic compound is below 4.8.
[0078] Such acidic compounds include mineral and organic acids such
as o- & p-bromoacetic acid, chloroacetic acid, chlorobenzoic
acid, chlorobutyric acid, chloropropionic acid, chloropropinic
acid, citric acid, cyano acetic acid, cyanobutyric acid,
cyanophenylacetic acid, cyclopropane 1:1 dicarboxylic acid,
dichloroacetyl acetic acid, dihydroxymalic acid, dihydroxytartaric
acid, lutidinic acid, maleic acid, malonic acid, naphthalene
sulphonic acid, o-, m- & p-nitrobenzoic acid, oxalic acid,
quinolinic acid, trichloroacetic acid, 2,4,6-trihydroxybenzoic
acid, 2,4,6-trinitrophenol, hydrochloric acid, sulphuric acid,
4-dodecylbenzene sulphonic acid (DBSA), picric acid, benzene
sulphonic acid, acetic acid, nitric acid, and amino benzene
sulphonic acid.
[0079] For tests in which a relatively rapid colour change is
desired, acidic compounds which may be conveniently used are those
with a pKa of less than 3.
[0080] Preferred acidic compounds are those with a pKa value of
less than 2, such as trichloroacetic acid, hydrochloric acid,
sulphuric acid, 4-dodecylbenzene sulphonic acid (pBSA), picric acid
and benzene sulphonic acid.
[0081] Particularly preferred acidic compounds are 4-dodecylbenzene
sulphonic acid (DBSA), sulphuric acid and hydrochloric acid.
[0082] The acidic compounds may be conveniently used in aqueous
solution at a concentration in the range of from 0.05 to 1.5
mol/dm.sup.3, preferably 0.15 to 0.6 mol/dm.sup.3 and most
preferably 0.25 to 0.4 mol/dm.sup.3.
[0083] However, in another embodiment of the present invention,
said acidic compound is supported on a test strip.
[0084] Said test strip may be made of any solid material that is
capable of supporting said acidic compound. As the test strip will
undergo colour reaction in the presence of a pH-dependent marking
substance, it is particularly preferred that said test strip is
made from a material which is white or lightly coloured and which
is not adversely effected by the presence of said acidic
compound.
[0085] Suitable materials are, for example, glass microfibre,
sintered glass, cellulose, cellulose nitrate, cellulose acetate,
finely woven fabrics or porous materials including cotton,
polypropylene, nylon, wood, neutral or acidic minerals. Basic
materials (such as Al.sub.2O.sub.3) are not suitable.
[0086] Compounds such as silica gel are not sufficiently acidic to
be used on the test strip as the acidic compound per se.
[0087] Depending upon the acid to be used in testing, it is within
the skill of the skilled person to select appropriate material for
the test strip.
[0088] The acidic compound may be optionally adsorbed onto a
carrier prior to being supported on the test strip. Suitable
carriers are non-basic, absorbent and light in colour, and may
conveniently include silica gel, cellulose, cellulose nitrate,
cellulose acetate.
[0089] Said acidic compounds may be conveniently supported on the
test strip at a concentration in the range of from 0.0003 to 0.3
mmol/cm.sup.2, preferably from 0.0015 to 0.15 mmol/cm.sup.2, and
most preferably from 0.003 to 0.03 mmo/cm.sup.2, based on the area
of the test strip.
[0090] In general, the test strip may comprise a narrow rectangular
piece of the acidic compound-impregnated material as described
above. In another embodiment, a smaller piece of such a test strip
may be conveniently attached to a plastic-laminated material
printed with appropriate instructions for use. The plastic
lamination would enable the test strip to be wiped clean.
[0091] In a further embodiment, the test strip may comprise a white
plastic-laminated opaque window mask in order to shroud the acidic
compound-impregnated test strip and to therefore enhance the
appearance of the colour change upon contact with the marking
substance.
[0092] The test strip may be conveniently located in a holder made
of a durable material, for example, polypropylene.
[0093] In a specific embodiment, such a test strip holder could be
specifically designed to enable dipping of the test strip into the
sump of an engine, that is to say, said holder could conveniently
be a very narrow unit containing therein the acidic compound
impregnated test strip attached to a disposable or re-usable
dip-stick.
[0094] In a preferred embodiment of the method of the present
invention, the oil composition comprises a marking substance
according to formula (e) IV and/or V as hereinbefore described.
[0095] The present invention will now be illustrated by the
following Examples, which should not be regarded as limiting the
scope of the present invention in any way.
EXAMPLES
Example 1
Preparation of the Test Strip
[0096] Test strips were prepared by submerging the test strip
material in a solution of DBSA in heptane for 2 seconds, draining
for 2 seconds and drying at 60.degree. C.
[0097] Experiments to determine the effect of DBSA concentration in
solvent were carried out at 5%, 10%, 15% & 20% in n-heptane and
optimised at about 10%.
[0098] Various materials were evaluated for suitability in the test
strip for the consumer point of sale spot test.
[0099] Plastic thin layer chromatography (TLC) plates coated with a
medium such as SiO.sub.2 appeared to be ideal as a polar substrate
that could support coating with acid. However, under certain
operating conditions gentle scuffing of the test strip substrate
easily removed the absorbant surface, causing a poor scuffy surface
and little acidified media. The process of cutting the TLC plate
material also induced cracking and media loss.
[0100] "Whatman" chromatography paper was found to be a very
suitable medium for a spot test. This medium was scuff resistant,
and could be easily cut to size giving a good finish.
[0101] The paper was tested in a variety of thicknesses and
porosity. Tests showed that "Grade 4 CHR" gave optimal performance.
The particular grade of paper was found to work with a variety of
acids. However, hydrochloric acid was found to make the paper
brittle. If desired to use a combination of hydrochloric acid with
"Whatman" chromatography paper Grade "4 CHR", the impregnated paper
may be conveniently supported on a solid material, such as wood or
plastic, in order to overcome any fragility of the impregnated
paper.
[0102] "Whatman" chromatography paper Grade "4 CHR" supporting DBSA
at a concentration of .about.0.002 g/cm.sup.2 performed very
well.
Example 2
Effect of Type of Acid on Colour Change in the Spot Test
[0103] A variety of acids that could be used to promote a colour
change were tested in the presence of a 15W50 synthetic oil
containing 4-(phenylazo)diphenylamine marker therein doped at 30
ppm.
[0104] The selection of mineral and organic acids were impregnated
at a concentration of approximately 0.01 mmol/cm.sup.2 onto a strip
of "Whatman" chromatography paper (Grade "4 CHR") and allowed to
dry according to the methodology described above in Example 1.
[0105] In the case of acids that were solid at room temperature,
the neat acid crystals (normally soft deformable material) were
forced into the paper surface with a palette knife in order to give
a uniform film of acid over the paper surface.
[0106] A drop of the 4-(phenylazo)diphenylamine-doped oil was
placed on to the acidified paper and any resulting colour change
was noted with time. The results are shown in Table 1.
1TABLE 1 Effect of Acid Type on Colour Change Appearance After 2
After 10 After 3 Acid minutes minutes hours Hydrochloric Acid 1 1 1
Sulphuric Acid 1 1 1 DBSA 1 1 1 Acetic Acid 0 0 1 Hexanoic Acid 0 0
0 Octanoic Acid 0 0 0 Decanoic Acid 0 0 0 Lauric Acid 0 0 0
Tridecanoic Acid 0 0 0 Tetradecanoic Acid 0 0 0 Pentadecanoic Acid
0 0 0 Hexadecanoic Acid 0 0 0 Heptadecanoic Acid 0 0 0 Octadecanoic
Acid 0 0 0 (0 = no colour change; 1 = strong pink/purple
colouration)
[0107] The results showed that DBSA and mineral acids promote a
good colour change. Acetic acid (pKa.about.4.75) gave a reaction
after 2-3 hours.
Example 3
Concentration of Marker
[0108] Oil compositions were prepared containing a range of
concentrations of from 0 to 30 ppm of 4-(phenylazo)diphenylamine
marker in 15W50 synthetic oil.
[0109] Strips of "Whatman" chromatography paper (Grade "4 CHR")
were impregnated with a solution of 10% DBSA in n-heptane and were
allowed to dry as described in Example 1.
[0110] A drop of each of the marker-doped oil compositions was
placed on the DBSA-impregnated test strips and the resulting colour
changes were observed after 2 minutes, 10 minutes and 5 hours. The
results are shown in Table 2.
2TABLE 2 Effect of marker concentration Conc. of Appearance Marker
in After 2 After 10 After 5 oil, ppm minutes minutes hours 0 0 0 0
3 0 0 1 6 1 2 2 12 3 3 3 15 3 3 3 18 4 4 4 25 4 4 4 30 4 4 4 (0 =
no colour change; 1 = very slight pink colouration; 2 = slight pink
colouration; 3 = distinct pink colouration; 4 = strong pink/purple
colouration)
[0111] The results showed that after 2 minutes there was a very
distinct colour change at marker concentrations of 18 ppm, 25 ppm
and 30 ppm. Such concentrations are highly suitable for testing by
the method of the present invention.
[0112] 6 ppm was the lowest concentration of the tested marker that
would indicate the presence of a colour change after 2 minutes. The
colour change was very slight and could be missed by an untrained
eye.
[0113] Although the testing method of the present invention is not
primarily designed to be a quantitative tool, using the marker
concentrations for this experiment (30 ppm for an undiluted oil
composition) it may be possible to give a very approximate
estimation of the percentage of genuine product present in an oil
composition.
[0114] In the field, fraudulent use commonly involves dilution of
genuine products to 25% or 33% of the original concentration. At
such a diluted concentration of marking substance, the trained eye
may also be able to distinguish a partially diluted oil composition
from an undiluted oil composition by using the testing method of
the present invention.
[0115] A strong pink/purple colouration is observed after 2 minutes
with 18 ppm of marker.
[0116] Using a marker concentration of 30 ppm, it may also be
possible to detect partial substitution of genuine product.
Example 4
Dip Test
[0117] A test was carried out to compare results of the method of
the present invention on oil compositions comprising different
marker systems, i.e. a 15W-50 synthetic engine oil composition
doped with 4-(phenylazo) diphenylamine at 30 ppmw and a similar oil
composition doped with "Sudan 455" marker (used as received ex.
BASF) (not according to formula (IV) of the present invention) at
60 ppmw. Testing was also carried out on an analogous unmarked oil
composition.
[0118] The oil compositions were spotted onto a "Whatman"
chromatography paper (Grade "4 CHR") containing dodecyl benzene
sulphonic acid (DBSA) at a concentration of 0.006
mmol/cm.sup.2.
[0119] Individuals were asked in double blind tests to compare the
colour quality of the spots formed on the test paper upon contact
with each of the lubricant compositions.
[0120] In spite of the fact that the oil composition comprising
"Sudan 455" marker therein was doped at twice the level of the
4-(phenylazo) diphenylamine-marked oil composition, 10 out of 10
people asked indicated that the spot which developed from
4-(phenylazo) diphenylamine-marked composition was the most
distinctly different from that of the unmarked oil spot.
* * * * *