Note: Descriptions are shown in the official language in which they were submitted.
CA 02325748 2000-09-25
WO 99149003 PCT/GB99/00959
FUEL COMPOSITION
This invention relates to a fuel composition, in particular a gasoline
composition for use in motor vehicles.
For many years manufacturers of spark ignition combustion engines have
been striving for higher efficiency to make optimum use of the hydrocarbon
fuels.
But such engines require gasolines of higher octane number, which has been
achieved in particular by addition of organo lead additives, and latterly with
the
advent of unleaded gasolines, by addition of MTBE. But combustion of any
gasoline gives rise to emissions in the exhaust gases, e.g. of carbon dioxide,
carbon
monoxide, nitrogen oxides (NOx) and toxic hydrocarbons and such emissions are
undesirable.
Motor gasolines have been discovered having high Octane Number but
producing low emissions on combustion.
The present invention provides an unleaded blend composition having a
Motor Octane Number (MON) of at least 80 comprising component (a) at least
5% or preferably at least 8 or 10% (by volume of the total composition) of at
least
one hydrocarbon having the following formula I
R-CH2-CH(CH3)-C(CH3)2-CH3
wherein R is hydrogen or methyl
and component (b) at least one saturated liquid aliphatic hydrocarbon having 4
to
12, 4-10 such as 5-10 e.g. 5 - 8 carbon atoms. In another embodiment component
(b) is contained in at least one of isomerate, alkylate, straight run
gasoline, light
reformate, light hydrocrackate and aviation alkylate. Preferably the
composition
comprises at least one of an olefin (e.g. in amount of 1-30%) and/or at least
one
aromatic hydrocarbon (e.g. in amount of 1-50%, especially 3-28%) and/or less
than
5% of benzene. The composition may preferably comprise 10-40% triptane, less
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
than 5% benzene and have a Reid Vapour Pressure at 37.8°C measured
according
to ASTMD323 of 30-120kPa. The composition is usually an unleaded motor
gasoline base blend composition.
The present invention also provides an unleaded formulated motor gasoline
which comprises said base composition and at least one motor gasoline
additive.
If R is hydrogen the hydrocarbon is triptane. If R is methyl the
hydrocarbon is 2,2,3 trimethylpentane. Especially preferred is triptane.
Triptane
and 2,2,3 trimethylpentane may be used individually or in combination with
each
other, for example, in a weight ratio of 10:90 - 90:10, preferably, 30:70 -
70:30.
The hydrocarbon of formula I, preferably triptane may be present in amount
of 5-95% or 8-90% such as 10-90%, or 15-65% e.g. 10-40% such as 20-35% by
volume or 40-90% such as 40-55% or 55-80% or 8-35% such as 8-20% by
volume. Unless otherwise stated all percentages in this specification are by
volume, and disclosures of a number of ranges of amounts in the composition or
gasoline for 2 or more ingredients includes disclosures of all sub-
combinations of
all the ranges with all the ingredients.
Triptane or 2,2,3 trimethylpentane may be used in a purity of at least 95%
but is preferably used as part of a hydrocarbon mixture e.g. with at least 50%
of
the compound of formula I. This mixture may be obtained for example by
alkylation of an iso alkane e.g. reaction of propene and iso butane or
obtained via
distillation of the product of a catalytic cracking reaction to give a C4
fraction
containing olefin and hydrocarbon, allcylation to produce a C4_g especially a
C6_9
fraction which is distilled to give a predominantly Cg fraction, which usually
contains trimethyl pentanes including 2,2,3 trimethyl pentane and/or 2,3,3
trimethyl
pentane. To produce triptane this fraction can be demethylated to give a crude
product comprising at least 5% of triptane, which can be distilled to increase
the
triptane content in the mixture; such a distillate may comprise at least 10%
or 20%
of triptane and 2,2,3 trimethylpentane but especially at least 50% e.g. 50-90%
the
rest being predominantly of other aliphatic C7 and C8 hydrocarbons e.g. in
amount
10-50% by volume. Triptane may be prepared generally as described in Rec.
Trav.
Chim. 1939, Vo1.58 pp 347-348 by J.P.Wibaut et al, which involves reaction of
pinacolone with methyl magnesium iodide followed by dehydration (e.g. with
sulphuric acid) to form triptene, which is hydrogenated e.g. by catalytic
hydrogenation to triptane. Alternatively triptane and 2,2,3 trimethylpentane
may
be used in any commercially available form.
2
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
The invention will be further described with triptane exemplifying the
compound of formula I but 2,2,3 trimethylpentane may be used instead or as
well.
The gasoline composition also contains as component {b) at least one liquid
saturated hydrocarbon of 5-10 carbons especially predominantly branched chain
C~
or Cs compounds e.g. iso C~ or iso Cs. This hydrocarbon may be substantially
pure
e.g. n-heptane, isooctane or isopentane or a mixture e.g. a distillation
product or a
reaction product from a refinery reaction e.g. alkylate. The hydrocarbon may
have
a Motor Octane Number (MON) of 0-60 but preferably has a MON value of 60-96
such as isomerate (bp 25-80°C). Research Octane Number RON may be 80-
105
e.g. 95-105, while the ROAD value (average of MON and RON) may be 60-100.
Component (b) may comprise a hydrocarbon component having boiling
point (preferably a final boiling point) higher than, preferably one boiling
at least
20°C more than, the compound of formula I e.g. triptane such as 20-
60°C more
than triptane but less than 225°C e.g. less than 170°C and
usually is of Motor
Octane Number of at least 92 e.g. 92-100; such components are usually alkanes
of
7-10 carbons especially 7 or 8 carbons, and in particular have at least one
branch in
their alkyl chain, in particular 1-3 branches, and preferably on an internal
carbon
atom and especially contain at least one -C(CH3)2- group.
The volume amount of the component (b) in total (or the volume amount of
mixtures comprising component (b), such as the total of each of the following
(if
present) (i)-(iv)) (i) catalytic reformate, (ii) heavy catalytic cracked
spirit, (iii) light
catalytic cracked spirit and (iv) straight run gasoline in the composition is
usually
10-80% e.g. 25-70%, 40-65% or 20-40%, the higher percentages being usually
used with lower percentages of component (a).
Component (b) may be a mixture of the liquid saturated hydrocarbons e.g.
a distillation product e.g. naphtha or straight run gasoline or a reaction
product
from a refinery reaction e.g. alkylate including aviation alkylate (bp 30-
190°C)
isomerate (bp 25-80°C), light reformate (bp 20-79°C) or light
hydrocrackate. The
mixture may contain at least 60% oc at least 70% w/w e.g. 60-95 or 70-90% w/w
liquid saturated aliphatic hydrocarbon.
Volume amounts in the composition of the invention of the component (b)
mixtures (primarily saturated liquid aliphatic hydrocarbon fractions e.g. the
total of
isomerate, alkylate, naphtha and straight run gasoline (in each case (if any)
present
in the composition) may be 4-60%, such as 4-25% or preferably 10-55% such as
25-45%. Alkylate or straight run gasoline are preferably present, optionally
3
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
together but preferably in the absence of the other, in particular in amount
of 2-
50% such as 10-45 e.g. 10-25%, 25-45% or 25-40%. The compositions of the
invention may also comprise naphtha e.g. in volume amount of 0-25% such as 2-
25%,10-25% or 2-10%.
The compositions may comprise a hydrocarbon component which is a
saturated aliphatic hydrocarbon of 4-6 carbons and which is more volatile and
has a
lower boiling point (preferably a lower final boiling point) than the compound
of
Formula I in particular one boiling at least 30°C such as 30-
60°C below that of
triptane at atmospheric pressure, and especially is itself of Motor Octane
Number
greater than 88 in particular at least 90 e.g. 88-93 or 90-92. Examples of the
hydrocarbon component include alkanes of 4 or 5 carbons in particular iso-
pentane,
which may be substantially pure or crude hydrocarbon fraction from alkylate or
isomerate containing at least 30% e.g. 30-80% such as 50-70%, the main
contaminant being up to 40% mono methyl pentanes and up to 50% dimethyl
butanes. The hydrocarbon component may be an alkane of boiling point (at
atmospheric pressure) 60-100°C less than that of triptane e.g. n and/or
iso butane
optionally in blends with the Cs alkane of 99.5:0.5 to 0.5:99.5, e.g. 88:12 to
75:25.
n Butane alone or mixed with isopentane is preferred, especially in the above
proportions, and in particular with a volume amount of butane in the
composition
of up to 20% such as 1-15% e.g. 1-8, 3-8 or 8-15%.
Cycloaliphatic hydrocarbons e.g. of 5-7 carbons such as cyclopentane or
cyclohexane may be present but usually in amounts of less than 15% of the
total
e.g. 1-10%.
Volume amounts in the composition of the total of isomerate, alkylate,
naphtha, straight run gasoline, 4-6 carbon liquid aliphatic hydrocarbon (as
defined
above) and cycloaliphatic hydrocarbon (in each case if present) may be S-60%,
such as 8-25%, 15-55% such as 30-50%.
The gasoline compositions of the invention also preferably contain at least
one olefin, (in particular with one double bond per molecule) which is a
liquid
alkene of 5-10 e.g. 6-8 carbons, such as a linear or branched alkene e.g.
pentene,
isopentene hexene, isohexene or heptene or 2 methyl 2 pentene, or a mixture
comprising alkenes which may be made by cracking e.g. catalytically or
thermally
cracking a residue from crude oii, e.g. atmospheric or vacuum residue; the
mixture
may be heavy or light catalytically cracked spirit (or a mixture there of).
The cracking may be steam assisted. Other examples of olefin containing
mixtures
4
CA 02325748 2000-09-25
WO 99149003 PCT/GB99/00959
are "C6 bisomer", catalytic polymerate, and dimate. The olefinic mixtures
usually
contain at least 10% w/w olefins, such as at least 40% such as 40-80% w/w.
Preferred mixtures are (xi) steam cracked spirit (xii) catalytically cracked
spirit
(xiii) C6 bisomer and (xiv) catalytic polymerate, though the optionally
cracked
catalytically spirits are most advantageous. Amounts in the total composition
of
the olefinic mixtures especially the sum of (xi) - (xiv) (if any present)
maybe 0-55,
e.g. 10-55 or 18-37 such as 23-35 or 20-55 such as 40-55% Amounts of (xi) and
(xii) (if present) in total in the composition are preferably 18-55, such as
18-35, 18-
30 or 35-55% (by volume).
The olefin or mixture of olefins usually has an MON value of 70-90, usually
a RON value of 85-95 and a ROAD value of 80-92.
The volume amount of olefins) in total in the gasoline composition of the
invention may be 0% or 0-30%, e.g. 0.1-30% such as 1-30% in particular 2-25, 5-
30, (especially 3-10), 5-18.5, 5-18 or 10-20%. Preferably the composition
contains at least 1% olefin and a maximum of 18% or especially a maximum of
14%, but may be substantially free of olefin.
The compositions may also contain at least one aromatic compound,
preferably an alkyl aromatic compound such as toluene or o, m, or p xylene or
a
mixture thereof or a trimethyl benzene. The aromatics may have been added as
single compounds e.g. toluene, or may be added as an aromatics mixture
containing at least 30% w/w aromatic compounds such as 30-100% especially 50-
90%. Such mixtures may be made from catalytically reformed or cracked gasoline
obtained .from heavy naphtha. Example of such mixtures are (xxi) catalytic
reformate and (xxii) heavy reformate. Amounts of the single compounds e.g.
toluene in the composition may be 0-35%, such as 2-33% e.g. 10-33%, while
amounts of the aromatics mixtures especially the total of the reformates (xxi)
&
(xxii) (if any) in the composition may be 0-50%, such as 1-33% e.g. 2-15% or 2-
10% or 15-32% v/v, and total amount of reformates (xxi), (xxii) and added
single
compounds (e.g. toluene) may be b-50% e.g. 0.5-20% or 5-40, such as 15-35 or 5-
25% v/v.
The aromatics usually have a MON value of 90-110 e.g. 100-110 and a
RON value of 100-120 such as I 10-120 and a ROAD value of 95-110. The
volume amount of aromatic compounds in the composition is usually 0% or 0-50%
such as less than 40% or less than 28% or less than 20% such as 1-50%, 2-40%,
3-
28%, 4-25%, 5-20% (especially 10-20%), 4-10% or 20-35% especially of toluene.
5
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
The gasoline composition may also be substantially free of aromatic compound.
Amounts of aromatic compounds of less than 42%, e.g. less than 35% or
especially
less than 30% are preferred. Preferably the amount of benzene is less than 5%
preferably less than 1.5% or 1% e.g. 0.1-1% of the total volume or less than
0.1%
of the total weight of the composition.
The compositions may also contain at least one oxygenate octane booster,
usually an ether, usually of Motor Octane Number of at least 96-105 e.g. 98-
103.
The ether octane booster is usually a dialkyl ether, in particular an
asymmetric one,
preferably wherein each alkyl has 1-6 carbons, in particular one alkyl being a
branched chain alkyl of 3-6 carbons in particular a tertiary alkyl especially
of 4-6
carbons such as tert-butyl or tert-amyl, and with the other alkyl being of 1-6
e.g. 1-
3 carbons, especially linear, such as methyl or ethyl. Examples of such
oxygenates
include methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether and
methyl
tertiary amyl ether. The oxygenate may also be an alcohol of 1-6 carbons e.g.
ethanol.
The volume amount of the oxygenate may be 0 or 0-25% such as 1-25%,
2-20% , 2-10% or 5-20% especially 5-15%, but advantageously less than 3% such
as 1-3% (especially of MTBE and/or ethanol). The oxygenate may also be
substantially absent from the composition or gasoline of the invention.
Aromatic anunes e.g. liquid ones such as aniline may be present if at all in
amount of less than 5% by volume, and are preferably substantially absent e.g.
less
than 100ppm. The relative volume ratio of the amine to triptane is usually
less than
3:1 e.g. less than 1:2.
The composition of the invention contains components (a) and (b), and the
formulated unleaded gasoline also contains at least one motor gasoline
additive, for
example as listed in ASTM D-4814 the contents of which is herein incorporated
by
reference or specified by a regulatory body, e.g. US California Air Resources
Board (CARB) or Environmental Protection Agency (EPA). These additives are
distinct from the liquid fuel ingredients, such as MTBE. Such additives may be
the
lead free ones described in Gasoline and Diesel Fuel Additives, K Owen, Publ.
By
J.Wiley, Chichester, UK, 1989, Chapters 1 and 2, USP 3955938, EP 0233250 or
EP 288296, the contents of which are herein incorporated by reference. The
additives maybe pre-combustion or combustion additives. Examples of additives
are anti-oxidants, such as one of the amino or phenolic type, corrosion
inhibitors,
anti-icing additives e.g. glycol ethers or alcohols, engine detergent
additives such
6
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
as ones of the succinic acid imide, polyalkylene amine or polyether amine type
and
anti-static additives such as ampholytic surface active agents, metal
deactivators,
such as one of thioamide type, surface ignition inhibitors such as organic
phosphorus compounds, combustion improvers such as alkali metal salts and
alkaline earth metal salts of organic acids or sulphuric acid monoesters of
higher
alcohols, anti valve seat recession and additives such as alkali metal
compounds,
e.g. sodium or potassium salts such as borates or carboxylates and colouring
agents, such as azodyes. One or more additives (e.g. 2-4) of the same or
different
types may be used, especially combinations of at least one antioxidant and at
least
one detergent additive. Antioxidants such as one or more hindered phenols e.g.
ones with a tertiary butyl group in one or both ortho positions to the
phenolic
hydroxyl group are preferred in particular as described in Ex.l hereafter. In
particular the additives may be present in the composition in amounts of 0.1-
100ppm e.g. 1-20ppm of each, usually of an antioxidant especially one or more
hindered phenols. Total amounts of additive are usually not more than 1000ppm
e.g. 1-1000ppm.
The compositions and gasolines are free of organolead compounds, and
usually of manganese additives such as manganese carbonyls.
The compositions and gasolines may contain up to 0.1% sulphur, e.g.
0.000-0.02% such as 0.002-0.01 %w/w.
The gasoline compositions of the invention usually have a MON value of at
least 80 e.g. 80-110 or 80-lOS such as 98-lOS or preferably 80 to less than
98,
such as 80-9S, 83-93 or 93-98. The RON value is usually 90-120 e.g. 102-120 or
preferably 90-102 preferably 90-100 e.g. 90-99, such as 90-93 e.g. 91, or 93-
98
e.g. 94.5-97.5, or 97-101 while the ROAD value is usually 85-11S e.g. 98-115
or
preferably 8S-98 such as 85-9S e.g. 8S-90, or 90-95 or 95-98. Preferred
gasoline
compositions have MON 80-83, RON 90-93, and ROAD 85-90, or MON 83-93,
RON 93-98 and ROAD 85-9S or MON 83-93, RON 97-101 and ROAD 90-9S.
The Net calorific value of the gasoline (also called the Specific Energy) is
usually at
least 18000 Btu/lb e.g. at least 18500, 18700 or 18,900 such as 18500-19500,
such
as 18700-19300 or 18900-19200; the calorific value may be at least 42MJIkg
e.g.
at least 43.5 MJ/kg such as 42-45 or 43-4S such as 43.5-44.SMJ/kg. The
gasoline
usually has a boiling range (ASTM D86) of 20-22S°C, in particular with
at least
2% e.g. 2-1S% boiling in the range 171-22S°C. The gasoline is usually
such that at
70°C at least 10% is evaporated while SO% is evaporated on reaching a
7
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
temperature in the range 77-120°C preferably 77-116°C and by
185°C, a minimum
of 90% is evaporated. The gasoline is also usually that 10-50% may be
evaporated
at 70°C, 40-74% at 100°C, 70-97% at 150°C and 90-99% may
be evaporated at
180°C. The Reid Vapour Pressure of the gasoline at 37.8°C
measured according
to ASTM D323 is usually 30-120, e.g. 40-100 such as 61-80 or preferably 50-80,
40-65, e.g. 40-60 or 40-50Kpa.
The gasoline compositions, when free of any oxygenates usually have a
H:C atom ratio of at least 1.8:1 e.g. at least 2.0:1 or at least 2.1 or 2.2:1,
such as
1.8-2.3:1 or 2.0-2.2:1. Advantageously the gasoline composition meets the
following criteria.
Atom H:C x [1 + oxy] x [ Net Heat of Combustion + ROAD] z y,
200
wherein Atom H:C is the fraction of hydrogen to carbon in the hydrocarbons in
the
composition, oxy means the molar fraction of oxygenate, if any in the
composition,
Net Heat of Combustion is the energy derived from burning llb (454g) weight of
fuel (in gaseous form) in oxygen to give gaseous water and carbon dioxide
expressed in Btu/lb units [MJ/kg times 430.35], and y is at least 350, 380,
410 or
430, in particular 350-440 e.g. 380-420 especially 400-420.
Preferably the motor gasoline of this invention comprises 10-90% of
triptane, 10-80% of component (b), 0-25% naphtha, 0-15% of butane, 5-20% of
olefin, 3-28% aromatics and 0-25% oxygenate, in particular with S-20%
aromatics
and S-I S% olefins.
In a preferred embodiment of this invention the motor gasoline of this
invention contains 8-65% of triptane (especially 15-35%), 0.1-30% such as 2-
25%
olefins, especially 3-14% and 0-35% aromatics such as 0-30% e.g. 5-35, 5-20
(especially S-15%) or 20-30%, and 5-50% component (b) mixtures e.g. 10-45%
such as 20-40%. Such gasolines may also contain oxygenates, such as MTBE
especially in amount of less than 3% e.g. 0.1-3% and especially contain less
than
1.5% benzene e.g. 0.1-1%. Such gasolines preferably have RON of 97-99, MON
87-90 and ROAD values of 92-94.5.
Examples of motor gasolines of the invention are ones with 5-25% triptane,
5-15% olefins, 15-35% aromatics and 40-65% component (b), in particular 15-
25% triptane, 7-15%, olefins 15-25% aromatics and 45-52% component (b)
mixture of RON value 96.5-97.5, or S-15% triptane, 7-1 S% olefins, 15-25%
aromatics and 55-65% compound (b) of RON value 94.5-95.5.
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Examples of motor gasolines of the invention are ones. having 1-15% e.g.
3-12% butane, 0-20% e.g. 5-15% ether, e.g. MTBE, 20-80 e.g. 25-70% of refinery
mixed liquid (usually C6-C9)streams (apart from naphtha) (such as mixtures of
(i)-
(iv) above), 0-25% e.g. 2-25% naphtha, 5-70% e.g. 15-65% triptane, with RON
93-100 e.g. 94-98, MON 80-98 e.g. 83-93 or 93-98, and RVP 40-80 such as 40-
65Kpa. Such gasolines usually contain 1-30% e.g. 2-25% olefins and 2-30% e.g.
4-25% aromatics. Amounts of olefins of 15-25% are preferred for RON values of
94-98 e.g. 94-96 and 2-15% e.g. 2-7% for RON values of 96-100 such as 96-98.
Other examples of firel compositions of the invention contain 8-18%
triptane, 10-50% e.g. 25-40% of total component (b) mixture, 5-40% e.g. 20-35%
of total aromatics mixture 15-60, ~e.g. 15-30% or 40-60% of total olefinic
mixture
and 0-15% total oxygenate e.g. 3-8% or 8-15%. Especially preferred
compositions have 8-18% triptane, 25-40% total mixed component (b) mixture,
20-35% total aromatics, and 15-30% total olefinics, or 8-18% triptane, 15-40%
total mixed component (b) mixture, 3-25% total aromatics mixture, and 40-60%
total olefinic mixture.
Further examples of fuel compositions contain 20-40% triptane, 8-55% of
the total component (b) mixture, e.g. 5-25% or 35-55%, and 0 or 5-25% e.g. 18-
25% total aromatics mixture, 0-55 especially 10-55 or 40-55% total olefin
mixture,
especially preferred compositions having 20-40% triptane, 5-25% total
component
(b) mixtures, 3-25% total aromatics mixture and 40-60% total olefinic mixture,
or
20-40% triptane, 35-55% total component (b) mixture 15-30% total aromatics
mixture and 0-15% e.g. 5-15% total olefin mixture, or in particular 20-40%
triptane, 25-45% or 30-50% total component (b) mixture, 2-15% total aromatics
mixture 18-35% total olefins mixture, and especially 3-10% or 5-18% olefins,
and
10-35% such as 10-20% aromatics (e.g. 10-18%).
Example of fuel compositions contain 30-55% e.g. 40-55% triptane, 5-30%
total component (b) mixture 0-10% total aromatic mixture, 10-45% olefinic
mixture and 0-15% oxygenates especially with the total of oxygenates and
olefinic
mixture of 20-45%. Other examples of fuel compositions contain SS-70%
triptane,
10-45% total component b, e.g. 10-25% or 35-45%, and 0-10% e.g. 0 or 0.5-5%
total aromatics Mixture, and 0-30% total olefinics mixtures, e.g. 0 or 15-30%,
especially 55-70% triptane 10-25% total component (b) 0 or 0.5-5% total
aromatics mixture and 15-30% total olefinic mixture.
Particularly preferred examples of fuel composition comprise 15-35% e.g.
9
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
20-35% triptane, 0-18.5% e.g. 2-18.5% olefin, 5-40% e.g. S-35% aromatics 25-
65% saturates and less than 1% benzene, and 18-65% e.g 40-65% triptane, 0-18-
5%
e.g. 5-18.5% olefins, 5-42% e.g. 5-28% aromatics, 35-55% saturates and less
than
1% benzene.
Another fi~el composition may comprise 25-40% e.g. 30-40% such as 35%
of alkylate, 10-25% e.g. 15-25% such as 20% of isomerate, 10-25% e.g. 15-25%
such as 20% of light hydrocrackate and 20-35% e.g. 20-30% such as 25% of
triptane and optionally 0-5% butane. Such a composition is preferably
substantially
paraffinic and is substantially free of olefins and aromatics.
Other fixel compositions of the invention may have different ranges of the
Antiknock Index (also known as The ROAD Index), which is the average of MON
and RON.
For ROAD Indexes of 85.5-88.5, the compositions may comprise 8-30%
triptane e.g. 15-30%, and 10-50% e.g. 20-40% total component (b) mixture, 5-
30%, e.g. 5-20% total olefins and 10-40 e.g. 15-35% total aromatics, or 8-30%
triptane, 10-50% total component (b) mixture, 5-40% total aromatic mixtures
e.g.
20-30% and 10-60% e.g. 30-55% total olefinic mixtures.
For ROAD Indexes of 88.5-91.0 the compositions may comprise 5-25%
(or 5-15%) triptane, 20-45% total component (b) mixture, 0-25% e.g. 1-10 or 10-
25% total olefins, and 10-35% e.g. 10-20% or 20-3S% total aromatics or 5-25%
(5-15%) triptane, 20-45% total component (b) mixture, 0-35% total aromatic
mixtures, e.g. I-15 or 15-35%, and 5-65% e.g. 5-30 or 30-65% total olefinic
mixtures.
For ROAD Indexes of 91.0-94.0 the fuel compositions of the invention may
comprise 5-65% e.g. 5-20, 20-30, 30-65 or 40-65% triptane and 5-40% (5-35%)
e.g. 5-12 or 12-40% (12-30%) total component (b) mixture I-30% e.g. 1-10 or
10-25% total olefins and 5-55% e.g. 5-15 or 15-35 or 35-55% total aromatics,
or
the above amounts of triptane with 0-55 e.g. 0.5-25% e.g. 10-25% or 25-55% of
aromatic fractions and 0 or 10-60% ~e.g. 10-30% or 35-60% total olefin
fractions.
For ROAD values of 94-97.9, the fuel compositions may comprise 20-65%
triptane e.g. 40-65% triptane, 0-15% e.g. 5-15% total olefins, 0-20% e.g. 5-
20%
total aromatics and 5-50 e.g. 30-50% total component (b) mixture, or the above
amounts of triptane and total component (b) mixture with 0-30% e.g. 10-30%
aromatic fractions and 0-30 e.g. 5-30% olefinic fraction, or the above amounts
of
triptane e.g. 20-40% triptane, total component b mixture, total olefins and
total
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
aromatics, with 2-15% aromatic fractions and 18-35% olefinic fractions.
The invention can provide motor gasolines, in particular of 91, 95, 97, 98
and 110 RON values, with desired high Octane Levels but low emission values on
combustion in particular of at least one of total hydrocarbons, total air
toxics,
NOx, carbon monoxide, and carbon dioxide, especially of both total
hydrocarbons
and NOx. Thus the invention also provides the use of a compound of formula I,
in
particular triptane, in unleaded motor gasoline ofMON at least 80 e.g. 80 to
less
than 98, e.g. as an additive to or component therein, to reduce the emission
levels
on combustion, especially of at least one of total hydrocarbons, total air
toxics
NOx, carbon monoxide and carbon dioxide especially both of total hydrocarbons
and NOx. The invention also provides a method of reducing emissions of exhaust
gases in the combustion of unleaded motor gasoline fuels of MON of at least 80
which comprises having a compound of formula I present in the fuel which is a
gasoline of the invention. The invention also provides use of an unleaded
gasoline
of the invention in a spark ignition combustion engine to reduce emissions of
exhaust gases. While the compositions of the invention may be used in
supercharged or turbocharged engines, they are preferably not so used, but are
used in normally aspirated ones. The compound of formula I e.g. triptane can
reduce one or more of the above emission levels better than amounts of
alkylate or
a mixture of aromatics and oxygenate at similar Octane Number and usually
decrease the fuel consumption as well.
The present invention is illustrated in the following Examples.
Exam lep s 1-6
In these Examples 2,2,3 trimethylbutane (triptane) 99% purity was mixed
with various refinery fractions and butane, and optionally methyl tertiary
butyl
ether, to produce a series of gasoline blends, for making unleaded motor
gasolines.
Formulated gasolines were made by mixing each blend with a phenolic
antioxidant 55% minimum 2,4 dimethyl-6-tertiary butyl phenol 15% minimum 4
methyl-2, 6-ditertiary-butyl phenol v~rith the remainder as a mixture of
monomethyl
and dimethyl-tertiary butyl phenols.
In each case the gasolines were tested for MON and RON, and their Reid
Vapour Pressure at 37.8°C and their calorific value, and their
distillation properties.
The results are shown in table 1.
11
CA 02325748 2000-09-25
WO 99149003 PCTIGB99100959
Table 1
Ezam le 1 2 3 4 5 6
Com sition % v/v
Tri tare 10.0 50.0 50.0 25.0 25.0 60.0
Butane 10.0 5.0 5.0 5.0 5.0 5.0
Mixed Fractions art 60.0 30.0 30.0 65.0 50.0 35.0
from
Na htha of which
Catal 'c reformate 5.0 0 0 18.1 0 1.3
HCC 6.48 18.62 17.68 0 9.31 22.73
LCC 48.52 0 19.05 46.90 36.41 0.00
SRG 0 11.38 3.27 0 4.28 10.85
Iso entane 0 0 0 0 0 0.12
Na htha 20.0 5.0 5.0 5.0 20.0 0.00
M'I'gE 0 10.0 0 0 0 0
Anal sis %v/v
~~ti~ 14.1 6.3 8.5 19.1 10.0 7.9
Olefins 23.5 3.2 11.7 21.4 18.5 3.8
Antioxidant m 15 15 15 15 15 15
Distillation C
T 10% . 43.6 58.0 58.4 51.2 54.0 60.0
T 50% 89.1 93.2 97.1 85.5 91.9 99.2
T 90% 154.0 177.8 176.9 140.4 159.0 185.0
Reid Va our Pressure?8.1 46.9 47.4 63.9 57.3 42.9
kPa
RON 95.0 97.3 97.0 97.0 95.0 99.4
MON 85.9 97.2 95.4 90.0 89.0 87.3
ROAD 90.45 97.25 96.2 93.5 92.0 93.35
~
In the above table mixed fractions means a blend of refinery fi~actions in
which HCC is heavy catalytically cracked spirit, LCC is light catalytically
cracked
spirit and SRG is straight run gasoline.
Example 7
The combustion characteristics of the gasolines of Ex.l-6 were tested
against standard unleaded gasolines. Combustion of the gasolines of Ex. l-
6gave
12
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
less carbon dioxide emissions than from equal volumes of the standard
gasolines of
similar ROAD Octane Number.
Example 8 and Comparative Ex A-C
The emission characteristics on combustion of a series of gasoline fuels
with 25% of different components were compared, the components being heavy
reformate (comp A), triptane (Ex8), alkylate (comp B) and a mix of 10% heavy
reformate and 15% MTBE (comp C). The gasoline fuels and their properties
were as follows. Formulated gasolines were made by addition of the phenolic
antioxidant in amount and nature as in Exl-7.
~ Fzamnle ~ A 8 B C
Composition
Butane 3 3 3 3
Reformate 22 22 22 22
Alkylate 40 40 65 40
Bisomer ('CCS') 10 10 10 i0
Heavy Reformate 25 10
Triptane 25
~gE 15
Density kg/1 0.7623 0.7163 0.7191 0.7424
RON 101.2 100.2 98.5 101.1
MON 89.4 93.2 88.3 90.2
ROAD 95.3 96.7 93.4 95.65
%Aromatics 3 8.9 13.9 13.9 23 .9
Olefins 10.2 10.2 10.2 10.2
Saturates 50.9 75.9 75.9 65.9
Benzene 0.9 0.9 0.9 0.9
The fuels were tested in a single cylinder research engine at a number of
difFerent engine settings. The speed/load was 20/7.2 rps/Nm/, or 50/14.3
rps/Nm
the LAMBDA setting was 1.01 or 0.95, and the ignition setting was set or
optimized. The emissions of CO, C02 , total hydrocarbons, NOx, and total air
toxics (benzene, butadiene, formaldehyde and acetaldehyde) were measured from
the exhaust gases. The results from the different engine settings were
averaged and
showed that, compared to the base blend (Comp. Ex. A) the emissions with the
13
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
compositions containing heavy reformate and M'TBE (Comp. C), 25% alkylate
(Comp. B) and 25% triptane (Ex8) were reduced, the degrees of change being as
follows.
Table 2
Exam le % CO %C02 %THC %NOx %TAT %FC
Com C E -4.9 -2.3 -6.2 -6.5 -9.2 +1.4
Com B al late -7.9 -4.5 -4.0 -8.0 -13.1 -2.9
8/tri tune -9.6 -5.6 -6.6 -10.1 -18.7 -4.1
Where THC is total hydrocarbons, TAT is total air toxics. The Fuel Consumption
(FC) was also measured in glkWhr and the change relative to the base blend are
also shown in Table 2.
Example 9-22
Gasolines were made up as in Ex 1-6 from components as shown in the
table below, and had the properties shown. They gave low carbon dioxide
emissions.
20
30
14
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Ezam le 9 IO 11 12 13 14 15
COm OSItIOn % V/V
Tri tare 10.0 25.0 60 10 18.0 10.0 24.0
Butane 4.7 4.7 4.71 0 0 0 0
Mixed Fractions a 85.3 70.3 35.29 76.21 73.6 90.0 45.4
art from
Na htha of which
Catal 'c reformate 10.0 10.0 0 21.28 10.0 15.3 25.2
CCS 0 0 0 10 0 0 0
Steam cracked s irit0 0 0 9.7 41.1 48.7 10.0
SRG 35.3 35.3 35.29 15.72 22.5 26.0 0
Iso entane 0 0 0 0 0 0 0
Na htha 0 0 0 13.79 8.4 0 30.6
Ethanol 0 0 0 5 0 0 0
Hea refornlate 10 10 0 9.51 0 0 0
Toluene 30 15 0 0 0 0 0
C clohexane 0 0 0 5 0 0 0
Li t h ocrackate 0 0 0 0 0 0 0
C6 Bisomer 0 0 0 0 0 0 10.2
Anal is %v/v
Aromatics 48.0 33.0 1 31 23.6 29.2 2.2
Olefins 0.1 0.1 0.1 6.1 8.8 10.4 12.5
Sul hur % wlw 0.000 0.000 0.002 0.001 0.004
Benzene 0.7 0.7 0.6 0.9 1.0
Antioxidant m 15 15 15 15 15 15 15
Distillation C
T IO% 58.0 55.9 53.6 51.5 61.0
T 50% 95.9 89.9 77.0 77.0 89.6
T 90% 156.6 157.0 136.9 142.6 140.4
Reid Va our Pressure51.6 54.0 56.9 60.0 50.0
kPa
RON 97.3 96.1 101.4 96.0 91.0 92.0 91.0
MON 88.1 87.8 88.8 83.8 81.6 81.8 82.0
ROAD 92.7 91.9 95.1 89.9 86.3 86.9 86.5
CA 02325748 2000-09-25
WO 99149003 PCT/GB99/00959
E=am le 16 17 18 19 20 21 22 23
Com sition % v/v
Tri tare 10 25 60 10 25.0 25.0 25.0 25.0**
Butane 2.96 2.96 2.96 0 3.32 1.07 3
Mixed Fractions 87.04 ?2.0437.04 76.2154.95 65.42 75.0
a art from Na
htha
Catal 'c refonmate19.78 4.78 21.2823.42 8.21 7.53 40
*
CCS 5 5 5 10
Steam cracked 47.42 47.4218.0 9.7 30.01 30.00
s irit *
SRG 15.72
late 31.53 27.20 37.47 22
N htha 13.7916.73 8.51
Ethanol 5
Hea reformate 9.51
C ciohexane 5 5 5 5
Li t h drocrackate7.93 7.93 7.93 0
C6 Bisomer 1.91 1.91 1.91 0 10
Anal is %v/v
Aromatics 32.1 23 8 31 16.4 16.8 15.6 25.5
Olefins 14 13.9 7.3 6.1 0.2 7.8 7.8 10.2
Benzxne 1.0 0.5 0.5 1.71
Sul hur % w/w 0.0002 0.0004 0.0004 0.0001
Antioxidant m 10 10 10 10 10 10 10 10
Distillation % 22.7 31.2 30.5 18.5
70C
100C 53.3 60.0 59.2 42.5
150C 95.8 94.9 95.1 97.2
180C 98.7 98.1 98.1 140
Reid Va . Press. 60.0 55.0 52.7 62.2
kPa
RON 97.3 98.9 104.0 96.0 98.6 100.9 102.9 102.7
MON 85.5 87.2 93.4 83.8 87.5 87.5 89.5 90.5
ROAD 91.4 93.0596.7 89.8 93.05 94.2 96.2 96.6
* In Ex.20-22 different fractions were used, e.g. different reformates.
** In Ex.23, the triptane was replaced by 2,2,3-trimethyl pentane.
16
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Examples 24-8 and Comparative Example D
Emission characteristics were obtained as in Ex.8 (apart from Lamba
settings of 1.00 and 0.95 set for the base fuel (Comp.D) on combustion of a
series
of gasoline fuels with different components namely reformate, (high
aromatics),
(Comp.D), triptane, Ex.24-27 and triptanelethanol Ex.28. Fuel consumption was
also measured in glkWhr. Formulated gasolines were made by addition of the
phenolic antioxidant in amount and nature as in Ex.l-7. The compositions were
as
shown in Table 3. The results were expressed in Table 4 as the percentage
change
in emissions or in fuel consumption compared to Ex.D.
15
25
35
17
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Table 3
Ezam le 24 26 27 28 D
Com ition % v/v
Tri tare 40 10 25 60 10
guy 2.96 2.96 2.96 2.96 2.96
Mixed Fractions a 87.04 72.04 37.04
art from
Na htha of which
Catal 'c reformate 19.78 4.78 21.28 25.25
*
CCS 5 5 5 5 10 5
Steam cracked s irit37.2 47.42 47.42 17.2 9.7 47.42
*
SRG 15.72
Toluene 4.53
Na htha 13.79
Ethanol
Hea refonnate 9.51
C clohexane 5 5 5 5 5 5
Li t h drocrackate 7.93 7.93 7.93 7.93 7.93
*
C6 Bisomer * 1.91 1.91 1.91 1.91 1.91
Anal is, %v/v
Aromatics 15.0 31.2 21.7 7.8 31.1 39.2
Olefins 13.4 16.2 16.1 8.3 6.5 16.2
Sul hur % w/w 0.007 0.007 0.047 0.007 0.012 0.007
Antioxidant m 10 10 10 10 10 10
Distillation C
T 10%
T 50%
T 90%
Reid V ur Pressure
kPa
RON 98.7 96.8 97.5 101.0 93.2 96.6
MON 86.1 82.8 83.7 89.6 82.4 82.5
ROAD 92.4 89.8 90.6 95.3 88.1 89.55
* Denotes that a different fraction was used, compared to the Examples in
other
Tables e.g. different raf~nate.
18
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Table 4
Euam % CO % C02 % THC % NOs % TAT % Fud Com osition
le
25 -3.3 -2.1 -4.7 -4.0 -5.0 -1.4
26 -8.6 -3.8 -8.7 -7.0 -1 9.1 -2.5
27 -17.4 -6.8 -10.5 -18.0 -35.3 -4.5
24 -14.9 -5.0 -7.9 -12.2 -28.7 -3.4
28 -11.7 -2.2 -3.2 -10.3 -10.1 +0.1
15
25
19
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
Table 5
Exam fe F.G 29
Com sition % v/v
Tri tare 25
Butane 0.75 0
Mixed Fractions (apart
from
Na htha of which
Catal 'c refonnate 11.0 7.5
*
Steam cracked s irit31.5 30.0
*
A1 late 40.9 37.5
Toluene 15.8 0
Anal sis, %v/v
Aromatics 34.2 15.6
Olefins 8.2 7.8
Saturates 57.6 ?6.6
Sul hur m 7.3 10
Benzene %w/w 0.75 0.64
Antioxidant m 10 10
Distillation % Eva 18.8 21.6
. 70C
E % 100C 44.4 64.5
E % 150C 92.8 93.3
E % 180C 96.4 98
Reid Va ur Pressure 56.8 52.2
kPa
RON 99.5 99.7
MON 87.6 89.3
ROAD 93.05 94.5
Examples 29 and Comparative Ex. F. G
3 gasoline fuels (Ex.29, F and G) were compared for production of
emissions on combustion in cars, The gasoline fuels had the compositions and
properties as shown in Table 5 and the formulated gasolines included
antioxidant as
in Ex. l . The fuels met the requirements of 2005 Clean Fuel specification
according
to Directive 98/70 EC Annexe 3. The cars were regular production models,
CA 02325748 2000-09-25
WO 99/49003 PCTIGB99/00959
namely 1998 Ford Focus (1800cc), 1996-7 VW Golf (1600cc), 1998 Vauxhall
Corsa (1000cc), 1994-S Peugeot 106 (1400cc) and 1998 lVfitsubishi GDI (1800cc)
each fitted with a catalytic converter. The Corsa had 3 cylinders, the rest 4
cylinders, while the 106 had single point injection; the Mitsubishi had direct
injection and the rest multipoint injection for their combustion.
2 separate base fuel experiments (comp F & G) were done. The emissions
were tested in triplicate in a dynamometer on the European Drive Cycle test as
described in the MVEG test cycle (EC.15.04+EUDC) modified to start sampling
on cranking and 11 sec. Idle as given in Directive 98/69 EC (the disclosure of
which is hereby incorporated by reference). The EDC test over l lkm comprises
the ECE cycle (City driving test) repeated 4 times followed by the Extended
Urban
Drive Cycle test (incorporating some driving at up to 120km/hr). The emissions
were measured out of the engine (i.e. upstream of the catalytic converter) and
also
as tailpipe emissions (i.e. downstream of the converter) and were sampled
every
second (except for the Focus) and cumulated over the test, the results being
expressed as g emission per km travelled. The emissions of the first ECE cycle
with the Focus were not measured. The emissions tested were for the total
hydrocarbons, COz, CO and NOx and the fuel consumption was determined on a
gravimetric basis. The geometric means of the emission and consumption results
across the 5 cars were obtained. The values for the Comparative fuels were
averaged.
In the following tests, the COz emissions averaged over the 5 cars were
lower with the triptane fixel (Ex.29) compared to the averaged base fuel
results
(Comp.F, G), namely Total tailpipe emissions in EDC tests, EUDC test and ECE
test, the reductions being respectively 2.8%, 2.7% and 2.8%. The Fuel
Consumptions averaged over the 5 cars were lower with the triptane fuel
(Ex.29)
compared to the averaged base results (Comp.F, G) in those same tests, the
reductions being respectively, 0.6%, 0.6% and 0.5%. The tailpipe emissions
results for THC, CO and NOx in at least some parts of the total EDC cycle
showed
trends towards triptane giving lower emissions than the base fuel, but the
dii~erences may or may not be confirmed in view of the limited number of
vehicles
tested.
The ECE tests simulates city driving and has 4 identical repeats of a
specified speed profile, which profile has 3 progressively higher speed
sections
interspersed by zero speed sections (the average speed being l9km/hr). The
first
Z1
CA 02325748 2000-09-25
WO 99/49003 PCT/GB99/00959
profile corresponds to driving from a cold start. In a cold engine, the
effects of
friction, lubricants and the nature of the fuel among others, differ from
those with a
hot engine in an unpredictable way, and it is with cold engines that most
tailpipe
emissions are produced, because the catalytic converter becomes increasingly
effective at reducing emissions when it becomes hot. In addition a Lambda
sensor
upstream of the converter controls the fuel/air ratio entering the engine, but
this is
not effective with a cold engine (resulting in an unregulated fueUair ratio);
after
cold start the sensor quickly becomes effective, (resulting in a regulated
fueUair
ratio), even when the catalyst is not yet hot enough to be effective. Thus
cold start
operations are different from hot running operations and yet contribute to a
large
amount of tailpipe emissions.
The out of engine results from the first profile ECE tests (simulating cold
start) with the above fuels (Ex.29 and Comp.F, G) were the same as the
tailpipe
emissions as the catalyst was not effective then. The results in these cold
start tests
for C02, HC, CO and NOx averaged over the Golf, Corsa, Peugeot and Mitsubishi,
and also averaged over the Golf, Corsa and Peugeot showed trends toward
triptane
giving lower emissions than the base fuel, but the differences may or may not
be
confirmed in view of the limited number of vehicles tested.
This period of cold start simulated as above may correspond in real life to a
period of time or distance, which may vary, depending on how the car is driven
and/or ambient conditions e.g. up to 1 km or 4 or 2 min, or a temperature of
the
engine coolant (e.g. radiator water temperature) of up to 50°C. The car
engine
may also be deemed cold if it has not been operated for the previous 4hr
before
start, usually at least 6hr before start.
Thus the present invention also provides of method of reducing emissions
of exhaust gases' in the combustion of unleaded gasoline fi~els of MON of at
least
80 e.g. 80 to less than 98 from cold start of a spark ignition combustion
engine,
which comprises having a compound of formula I present in the fuel which is a
gasoline of the invention.
35
22
