CA2178955A1 - Use of tertiary-hexyl methyl ether as a motor gasoline additive - Google Patents
Use of tertiary-hexyl methyl ether as a motor gasoline additiveInfo
- Publication number
- CA2178955A1 CA2178955A1 CA002178955A CA2178955A CA2178955A1 CA 2178955 A1 CA2178955 A1 CA 2178955A1 CA 002178955 A CA002178955 A CA 002178955A CA 2178955 A CA2178955 A CA 2178955A CA 2178955 A1 CA2178955 A1 CA 2178955A1
- Authority
- CA
- Canada
- Prior art keywords
- methyl ether
- composition
- blend according
- mon
- ron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/10—Liquid carbonaceous fuels containing additives
- C10L1/14—Organic compounds
- C10L1/18—Organic compounds containing oxygen
- C10L1/185—Ethers; Acetals; Ketals; Aldehydes; Ketones
- C10L1/1852—Ethers; Acetals; Ketals; Orthoesters
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
- C10L1/023—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only for spark ignition
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L10/00—Use of additives to fuels or fires for particular purposes
- C10L10/02—Use of additives to fuels or fires for particular purposes for reducing smoke development
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L10/00—Use of additives to fuels or fires for particular purposes
- C10L10/10—Use of additives to fuels or fires for particular purposes for improving the octane number
Abstract
A tertiary-hexyl methyl ether composition comprising 2-methoxy-2,3 dimethyl butane (MDMB) in an amount of at least 10 % by weight based on the total tertiary-hexyl methyl ethers is useful as an octane booster for motor gasoline or motor gasoline feedstock.
Description
wo 95/16763 2 1 7 8 9 5 5 PCT/USg4/14234 USE OF l~;KllARY-HEXYL METHYL ~;NI~;K AS A MOTOR GASOLINE
ADDITIVE
This invention relates to the use of one isomer of tertiary-hexyl methyl ether, which is 2-methoYy-2,3-dimethylbutane, as an octane booster in motor g~coline Generally, any component that has a research octane number over 105 and a motor octane number over 95 is considered to be an octane booster for use in motor gasoline. It is well known in the art that ethers 0 made from C4 and Cs oleffns are eYcelle.nt octane boosters. Methyl tertiary-butyl ether (MTBE) made from isobutene, a C4 olefin, has a research octane number (RON) of 118 and a motor octane number (MON) of 100; and tertiary-amyl methyl ether (TAME) pro~ ce~ from Cs olefins has a RON of 111 and a MON of 98 accordi.lg to Un7elm~n, Oil & Gas Journal, Volume 44, April 15, 1991.
It is also well known that these ethers have a higher octane booster number than their counterpart olefins. "Physical 1~O~ of Hydrocarbon and Non-Hydrocarbon Co~ ounds" ASTM data series publiG~tion DS 4B, 1991 states that the octane numbers for one of the parent olefins of TAME, 2-methyl-2-butene, is 97 for the RON and 82 for the MON. Ftherific~tion of this Cs olefin increases the octane numbers to 111 for the RON and 98 for the MON. While the art te~hes that ethers produced from C4 and Cs olefins are excellent octane boosters, it te~clles away from the use of ethers produced from C6 and heavier olefins.
For example, in Pescarollo et al.'s article, "Etherify light g7~colines"~
Hydrocarbon Proceccing, February 1993, pp 53-60, he states that " . . . ethers derived from C6 and heavier olefins do not cignifiç~ntly enh~n~ e octane over the parent olefins".
Also, US-A-4,193,770, and its equivalent, DE-A-2,854,250 (1979) 3 o te~hes that the octane numbers of the C6 ethers are no higher than those of the parent olefins mixed with the same amount of methanol. The blending octane numbers for tertiary-hexyl methyl ether which is pro~ ce~l from a C6 olefin are reported as being 100 for the RON and 90 for the MON, but no mention is made of any specific isomers, inrhlding 2-methoxy-2,3-dimethylbutane (MDMB). Hence, there is no recognition or te~ing that MD~IB is effective as an octane booster. The reported numbers serve to -2- ~ 17,'69~
teach away from investig~ting the performance of ether produced from C6 or C7 olefins.
This reference te~heS the importance of etherifying C4 and Cs olefins separately from each other bea~-se of the di~erelll re~ction kinetics.
5 Also stressed is the ~ol l~ce of keeping each of these fractions separate from the C6 olefin fraction, which forms tertiary hexyl methyl ether, ber~llse there is no prove~l.ent in octane rating as co...l ~red to the ethers from the C4 and Cs olefinc. The reference goes as far as saying that any reported increases in octane rating for ethers from C6 and q olefins, are "illusory".
See cohlmn 3, lines 5 to 13 and 26 to 37.
This reference sets up a major prejudice ~e~inct using C6 ethers as motor gasoline octane boosters. And there is absolutely no m~ntion of MDMB.
MICROLOG-88-03391 from Energy Res. Abstr., 13(22), Abstr. No.
5031, 1988, also te~hes against the use of ethers prod~lced from C6 olefins in that "pre~lictiQnC for C6 ethers were not carried out bec~l~ce there was virtually no .. l,love"lent in octane number when co...p~red with its precursors".
EP-A-0 036 260, tlicrloses the use of ethers prod-lced from a ~i~.lule 20 of C4 through q olefins as components in a motor ~colin~ blend from a refinery catalytic cracker unit, with 7% being C6 olefinc, but lei"rorces the belief that the octane booster effect is due to the ethers prod~lced from C4 and Cs olefins rather than those ethers produced from C6 or q olefinc.
It would be desirable if ethers pro~ced from C6 olefins could be used 2 5 as motor octane boosters. Current market predictions indicate that there will be a glut of propylene, which could be used to make C6 olefins, in the market place within the next ten years. Currently, propylene is sent to the motor g~coline pool from refinery catalytic crackers, but the propylene does not boost the octane. It would be very profitable if one could determine a way to 3 0 coll~el l propylene into an octane booster.
SUMMARY OF THE INVENTION
This invention relates to using an octane boosting amount of a 35 tertiary hexyl methyl ether co",~onent col~ g 2-m~thc-Yy-2,3-dimethyl butane (MDMB) which enables providing a blend CO~ iSi~g (a) motor gasoline or motor gasoline feedstock; and (b) an octane boosting amount of a tertiary hexyl methyl ether component colllplish~g 2-methoxy-2,3-dimethyl butane (MDMB) in an ~mount of at least 10% by weight based on the total weight of tertiary hexyl methyl ether, wherein composition (b) has a Research Octane Number (RON) and/or a Motor Octane Number (MON) greater than those of co~ osilion (a).
One emboAim~-nt includes providing a blend wherein the tertiary hexyl methyl ether component of composition (b) colll~ lises in various 0 amounts and ranges, inrlllding, greater than 10%, preferably from 20 to 100~, more preferably greater than 50%, even more yrcferably from 60~o to 100%, and most prefe~bly greater than 80% by weight of MDMB.
Another embodiment inrllldes providing a blend wherein coLu~osilion (b) co.~ greater than 50%, preferably from 60% to 100%, and more 15 l,refe~ably greater than 80%, by weight of the tertiary hexyl methyl ether.
Yet another emboAiment inçl~ldes providing a method of increasing the octane number in motor g~coline collll,lishlg blending MDMB with the motor gasoline or with a motor g~coline feedstock to boost the octane number of the motor g~coline or motor g~colin~. feedstock which co~ a 2 o sufficient ~mollnt of composition (b) to boost the octane number of co..l~ullent (a) by at least 1, l,lcfeldbly by at least 2, and more prefelably by at least 3 units.
Still another emboAim~nt inrllldes the use of a tertiary hexyl methyl ether co-llpûllcnt co...l-t;~ing MDMB and having a blending RON greater than 100 and a ble-nAin~ MON greater than 90, as an octane booster for motor ~coline The tertiary hexyl methyl ether component co~ lisillg MDMB may be ~rcpared by dimerizing propylenes and ~d(lition~l emboAim~o.ntc of the present invention in~ de a blend wherein composition (b) is made by a process cOlll~lisillg:
(i) dimerizing propylene to form dimethylbutenes; and (ii) etherifying the dimethyl butenes with meth~nol, to form the desired col~o~ilion and/or a blend.
~AAition~lly, another embo~liment inÇllldec the funher tre?~tment wherein step (ii) comprises panial etherifiç~tion and is followed by (iii) ~ 17 '76q55 hydrogen~ti-n of unetherified dimethylbutenes to form a tertiary hexyl methyl ether composition COlll~liSillg MDMB and dimethyl butanes.
DETAILED DESCRIPIION OF THE INVENTION
Not all of the isomers of tertiary-hexyl methyl ether produced from C6 olefins are suitable for use as octane boosters. The four isomers of tertiary-hexyl methyl ether (C6 H13-OCH3) are as follows:
1) 2-Methoxy-2,3-dimethylbutane(MDMB) 2) 2-Methoxy-2-methylpent~ne (2MMP) I
I
3) 3-Methoxy-3-methylpentane (3MMP) I
I
2 1 78~55 4) l-Methoxy-l-methylcyclopentane (MMCP) I
CH2 /cH2 C
l-Metboxy-l-methylcyclopentane (MMCP) is conci~lered an isomer of tertiary-hexyl-methyl ether even though it has two fewer hydrogen atoms.
One isomer of tertiary-hexyl methyl ether has been found to be a very useful high octane booster for use in motor g~coline~ That particular isomer 15 is 2-methoxy-2,3-dimethylbutane (MDMB).
MDMB may be ~epared from propylene and methanol by first llim~ri7ing the propylene to dimethylbutenes (2,3-dimethyl)-(1 and/or 2)-butene), and then by ethe~ i-lg the dimethylbutenes with meth~nol, as shown in the following reaction equationc Both 2,3-dimethyl-1-butene and 20 2,3-dimethyl-2-butene react with methanol to form the desired product ether.
2 CH3CH = CH2 ~ CH3--CH- C = CH2 propylene 2,3-dimethyl-1-butene CH3--CH - C = CH2 + CH30H ~ CH3--CH - C--OCH3 3 o 2,3-dimethyl-1-butene methanol (DMB) CH3 2-methoxy-2,3-dimethylbutane 3 5 (MDMB) ,~17~q~5 Olefin dimerization and codimerization processes are known in the art. The propylene may be dimerized to dimethylbutenes (DMB) using a tnng~ten catalyst, such as that tli~rlose~ in U.S. Patent 5,059,739. The dimethylbutenes (DMB) may also be produced using nickel with specific organo-phosphine lig~n~l~
In the event, the tun~cte~ catalyst is used, the ratio of olefin to tungsten should be such that a catalytic amount of the tnn~tçn complex is used. The reaction may be run in either a batch or a co,-l;.,llous manner.
The re~çtion ~res~ule is normally the p'es~ulc generated by the olefin at the reaction tempeldlule, ~lth~lgh the ple~ulc may be increased with an inert gas. The re~ction temperature may range, for eY~mple, from about 40 to 100~C, with 50 to 80~C being preferred. The reaction or resi~len~e time may be, for example, from S min~ltes to about 3 hours, with 0.5 to 2.0 hours being preferred. The preferred embodiment uses a catalyst which is prepared by taking a tungsten salt and an aniline to form a complex of the t~mgstçn salt and ~niline S~1bst~nti~lly all of the hydrogen chloride pro~l~lce~l in this re~ction is removed from the sol~ltion during the course of the re~ction After form~tion of the tlmgstçn and aniline complex, an alkyl ~ ",;n~", halide is added to the sohltion to form the active catalyst system of the invention. The l,refelled feedstock is refinery grade propylene, after sufficient removal of water and other catalyst poisons.
The etherific~tion of the dimethylbutenes with meth~nol to prcpare MDMB may take place in a m~nner similar to the ~lepalalion of methyl tertiaIg-butyl ether (MTBE) from isobutylene or the preparation of tertiary-amyl methyl ether (TAME) from isoamylenes. The re~ o~ takes place over the acid form of an ion eY-~h~nge resin.
The present invention involves the feeding of a llli,LIure conl~ g DMB and methanol into the feed zone of a reactor (i.e., a fixed-bed guard reactor), and cont~cting the reslllt~ns ll~ lure of DMB and methanol with a fixed bed acidic cation exchange resin (e.g., Amberlys~) 15) in the reaction zone, thereby catalytically re~cting the DMB with the methanol under conditions which favor forming the res~llt~nt 2-methoxy-2,3-dimethylbutane (MDMB).
Where the etherification step of the present invention is practiced in a catalytic ~ till~tion process, the catalytic material may be in any form which WO 95/16763 2 ~ 7 8 9 5 5 PCT/USg4/1423~
pcllllils its incorporation into a tlictill~tion tower, such as a fixed bed, butmay also be in a form which serves as a di~till~tion p~ing, for example, rings, s~ lles, balls, irregular pieces, sheets, tubes, spirals, packed in bags,plated on grills or screens, and reticlll~ted polymer foams.
Catalysts which have been found to be suitable for use in the etherification step of the present invention are resin catalysts such as cation h~e resin catalysts, acidic resin catalysts, macroreticular s~llfonic acid cation eYrh~nge resin catalysts, and solid acid catalysts. Still others have used a zeolite as an etherific~fion catalyst. Preferred catalysts for purposes of thepresent invention, however, are acid catalysts, such as acidic resin catalysts.
A more ~refelled catalyst for purposes of the present invention is a macroreticular sulfonic acid cation eYrh~n~e resin such as a slllfon~te~
copolymer of poly~lylelle-divinyl-ben7ene. Such catalysts inrlude Amberlyst t!~) 15 and 15C (m~rkçted by Rohm and Haas), Lewatit SPC 118 and SPC 118 BG (marketed by Miles/Bayer), and Dowex M-31 and M-32 (marketed by the Dow Chemical Co.). A special version of this type of catalyst, i.e., Dowex DR-2040 (marketed by the Dow Ch~mic~l Co.), is used specifi~lly for reactive dict~ tinn It has been found that eqllilibrinm co--vel~ion to ether is only 50-60%, so it is expected that catalytic tlictill~tion will be advantageous in the etherific~fion step. Catalytic dictill~tion is commercially pr~ ticed in the prodllction of MTBE and this process has been extensively explored with TAME. Therefore, there is every reason to expect that catalytic ~icfill~tion would be advaIltageous when applied to the process for producing ethers from C6 olefinc.
When the ether is pro~l~lce~ from a C6 olefin which has been formed by ~im~ri~in~ propylene, the co---~osilion of the reslllting ~-~lu e of isomers may be as pure as 98 wt% MDMB, 2 wt% 2MMP, with n~ligihle amounts of 3MMP and MMCP. When the C6 olefin is pro~ ed in a refineIy catalytic cracker, the isomer ll~ ule is di~ere--l, with more than 50% being 2MMP
and ~plo~;...~tely 7% being MDMB.
It is well known in the art that ethers are used as motor E~coline additives to enh~nce the quality of the motor gasoline due to el-viro.. ent~l regulations, both eYictin~ and pending in the USA. By using an oxygenate 35 rather than its counter part olefin in motor gasoline, less carbon monoYide pollution is produced upon combustion of the motor g~coline Also, the rules ~17 ~q5~
re~ ting reformnl~ted ~coline which is a particular type of motor ~coline, require that a lower olefin content be present in the g~coline due to the fact that olefins contribute to ozone formation more than their counter part ethers. An ~d~liti~n~l advantage of using the ether rather than the olefin in 5 motor g~coline is that the ether has a lower Reid vapor pl~s~ulc, which reduces evaporative emiccionc which contribute to pollution.
The ~d~lition of the MDMB to the motor e~colinP, or motor ~colinP, feedstock to boost the octane may be ~ccomplished in several ways. One method includes the preparation of a blend C(illlpliSillg the ll~lure of two 0 compositions, (a) and (b), wherein composition (a) cO.~;cl~ of the motor ~colinP, or motor &~coline feedstock which is blended with colllposilion (b) which colll~lises an octane boosting amount of a tertiary hexyl methyl ether collll,ollent comprising 2-mPthoYy-2,3-dimethyl butane (MDMB) in an ~mollnt of at least 10% by weight based on the total weight of tertiary hexyl 15 methyl ether, wherein the colll~osilion (b) has a Research Octane Number (RON) and/or a Motor Octane Number (MON) greater than those of colll~osilion (a).
In ~d~lition to the tertiary hexyl methyl ethers and the MDMB, co,l.posilion (b) may inrhlde other colll~ ne~b. These ~ ition~
20 colll~ollents may be any other hydroc~l.ol~s typically found in motor g~colin~
or motor g~colin~ fee~lctocl~c~ inrlu~ling, but not limited to, aro...s~;rc, olefinc, and saturates.
These ~d(lition~l hydrocarbons may or may not be cqncidered useful as octane boosters. In the case where the other hydroc~l,olls are useful as octane boosters, composition (b) may inclucle either MTBE or TAME, or n~i~lures thereof.
Co~ osilion (b) may have a RON greater than 95, preferably greater than 100, and/or a MON greater than 85, ~refel~bly greater than 90.
Optionally composition (b) has a blen~ling RON greater than 100, ~le~lably greater than 105 and/or a blen~lin~ MON greater than 90, prefelably greater than 9S.
The tertiary hexyl methyl ether colll~onent of col,l~osilion (b) may col~lise greater than 10%, prefelably from 20 to 100%, by weight of MDMB. Optionally, this tertiary hexyl methyl ether collll~onent of co~ osilion (b) may co~ lise from 50 to 100%, l,lerel~bly greater than 80%, by weight of MDMB.
The tertiary hexyl methyl ether component may have a RON greater than 100 and/or a MON greater than 90. Optionally, this tertiary hexyl methyl ether component may have a blending RON greater than 100 and/or a blen~ling MON greater than 90.
The MDMB component of co"",osilion (b) may have a RON greater than 105 and/or a MON greater than 95. Optionally, the MDMB component may have a blen~ling RON greater than 105 and/or a blen-ling MON greater than 9S.
The resultin~ blend may have a RON greater than 90, l"~felably 0 greater than 93, and/or a MON greater than 80, preferably greater than 83.
A sufficient amount of composition (b) must be blended with co".~osilion (a) such that the octane number of component (a) is boosted by at least 1, preferably by at least 2, and more prefelably by at least 3 units.
The resnlting blend may which comprise greater than 1%, preferably greater than 2%, and most preferably greater than 5%, by volume of MDMB.
In addition to its use as an octane booster, MDMB has the added benefit of not significantly increasing the RVP of the motor g~coline blend as is typical with other octane boosters, such as MTBE or TAME.
For example, MTBE has a blçn~ling RVP of 57.9 kPa (8.4 psi) and TAME has a blending RVP of 27.6 kPa (4.0 psi), both of which are higher than that of MDMB being 6.9 kPa (1 psi).
When the starting motor g~coline fee~lctQck has a high RVP level, one could be limited on how much MTBE or TAME ~d~lition is possible to achieve the required octane requirçm~-ntc, while at the same time, not ~Y~eetling the RVP limit.
Therefore, an additional embo~imçnt of the present invention inl~hldes the use of more than one octane booster to achieve the ",~xi, octane boosting effect and without the co"esponding undesirable increase in RVP.
For example, one could make a blend COl"~,iSi"g the ~ddition of MTBE and/or TAME up to the m~x;...,.... RVP limit of the motor g~colin~
product as set by an el,viro.~..ent~l st~nd~rd. Then, MDMP, either alone or in llli~ure with the tertiary hexyl methyl ether, could be blended into the motor ~coline to achieve on even higher octane number without incurring 35 any increase in the RVP of the final blend of motor ~coline.
~ 1 7 ~ ~5~
One embo~lim~nt of the invention inr~ es a blend which cont~inc a sufficient amount of composition (b) to boost the octane number of co~ ,onent (a) by at least 1, while at the same time increasing the Reid vapor plcs~urc of component (a) by less than 13.8 kPa (2 psi), preferably by less than 6.9 kPa (1 psi), and more preferably by less than 3.4 kPa (0.5 psi).
The MDMB may be preparcd using a process colllplising (i) ~limeri7ing propylene to form dimethylbutenes and (ii) etherifying the dimethyl butenes with methanol. Optionally, wherein step (ii) colll~lises partial etherification, the process may further col~ lise the ~ ion~l step of 0 (iii) hydrogen~tion of the unetherified dimethylbutenes to form a tertiary hexyl methyl ether composition COlll~liSillg MDMB and dimethyl butanes.
Co~ .osilion (b) may co..l;l;.. dimethylbutenes and may also cont~in less than 1% meth~nol and/or less than 5% olefinc Composition (b) may co~ greater than 50%, ~rcferably from 60% to 100%, and more 15 l,refelably greater than 80%, by weight of the tertiary hexyl methyl ether.
By ble-n~ling the pre~ared MDMB, with a motor g~coline or motor g~coline feedstock, the octane number of the blended ~coline may be increased by 1 or more units, prcfe~ably 2 or more units, and most preferably 3 or more units, over the original octane number of the motor gasoline or 20 motor g~coline feedstock.
The foregoing invention will now be illustrated by, ~lthollgh not limited to, the following examples.
EXAMPLES
EXAMPLE I
2-MMP Col-lpa~alivc Example This co..~p~ativc example illustrates that not all ethers prodllce-l from 3 C6 olefins are useful as octane boosters.
An ion eY~ h~nge resin in the acid form (Amberlyst R15, washed with methanol) was added to a 5000 mL round-bottom _ask along with 1000 g of 2-methyl-1-pentene and 416 g methanol. The slurry of resin catalyst was stirred magnetically and reflmre~ at ~tmospheric pressure for 16 hours. In 35 the relll-x;--g process, the material boils at ~tmospheric prcssule and conde-ncec the vapors back into the boiling material. The resin catalyst was WO 95/16763 2 ~ 7 8 9 5 5 PCT/USg4/14234 filtered from the product lllL~Iure, and then uncollvelled methanol and methyl pente-nes were distilled away from the product ether (2MMP). The uncollvelled materials were placed back in the re~ction flask with the resin catalyst and refluxed again for another 16 hours. This procedure of reaction s followed by removal of product ether was repe~te~l three times. This was desirable in order to achieve good collvel~ion of the starting material since the etherific~tion re~ction is equilibrium limite~l The product ether was distilled again (boiling point 112~C) to yield product purity of 99.4% by GC
analysis.
0 The octane numbers and Reid vapor ~les~ure results were mç~cllred using the st~n~l~rd test methods well known in the art. The Research Octane Number (RON) was 88.3 and the Motor Octane Number (MON) was a~rc.-;...~tçly 90. The precise MON could not be ~p~cl~ed as the fuel/air ratio was set at the hiehest setting available on the test eneine~ In the st~n(l~rd test procedure, the fuel/air ratio is co~ lly increased until m~x;.",),- knock is obtained. The Reid vapor plcs~ure was 1.25 psi.
These results are concictent with the reported octane numbers for ethers of C6 olefinc, and support the industry view (for example, as e,-~fessed in US-A~,193,770) that such ethers are not useful as octane boosters for 2 o motor ~colinç~
EXAMPLE II
MDMB - the Invention This example of the invention illustrates that one of the ethers pro~h~ce~ from C6 olçfinc, spe~fic~lly MDMB, is useful as an octane booster.
2-Methoxy-2,3-dimethyl butane (MDMB) was ~ ed from 2,3-dimethyl-2-butene (2112 g) and methanol (879 g) in a similar m~nnçr as described for prepa~ation of 2MMP in Example I. The product had a boiling point of 115C and a product purity of 98.2% 2-methoxy-2,3-dimethylbutane with the balance being 2-methoxy-2-methyl pentane from 2-methylpentene h~ulil~ in the starting material. The Research Octane Number mç~cllred for this MDMB rich product was 108.1 and the Motor Octane Number was 96.8. The Reid vapor ~res~ule was 7.3 kPa (1.06 psi).
- 12- ~ q 5 Analysis of Examples I and II
The octane numbers from Examples I and II along with those of C4 and Cs olefins are reproduced below in a table format for easy co,.,r ~ on Parent Olefin Ether RON MON
C~ TAME 111 98 C6 MDMB 108.1 96.8 2MMP 88.3 less than 90 One can see that unexpectedly, and con~ to the prejudice arising from the prior art investig~tion of C6 olefin ether, MDMB has RON and MON values which _ake it sul~ gly good as an octane booster for motor g?~colin EX~MPLE III
In ~d~lition to the coJl,l)o"ent RON, MON, and Reid vapor l,le~uie (RVP) numbers being determined, a set of col,esponding blen~ling values for 5 MDMB was also ascertained. As it is well known to one of ordi"a,~ skill in the art, the "blen~ling" RON, MON, and RVP values vary based upon the base g~coline composition- Typically, the "Blending Values" (BV) are higher for RON and MON and are slightly lower for RVP.
Blends of appro-;",~tely 14, 19, and 25% volume MDMB/volume 20 g~colinet as synthe-ci7e~l in Example II, were plepared using two diL~ere, g~colin.os, A and B, as described below.
Gasoline AG~coline B
RVP, kPa 50.3 (7.3 psi)53.8 (7.8 psi) The res~llting RON, MON, and Reid vapor pres~ure numbers were 25 me~c~lred for each of the blends with the following results.
Gasoline MDMB RON MON RVP RVP
Vol %Blend Blend Blend, Blend, kPa psi A 13.895.6 85.2 45.5 6.6 A 18.796.3 85.8 43.4 6.3 A 24.397.3 87.0 37.9 5.5 Average A ~ 96.4 86.0 42.1 6.1 B 14.298.8 88.2 42.7 6.2 B 19.299.4 88.8 46.2 6.7 B 24.999.9 89.6 40.7 5.9 AverageB --- 99.4 88.7 43.4 6.3 The values of the blend were then used in the following m~nner to c~ te the l,lopellies of the finiche~ blend. RVP is used as an example.
VOL ga~ e VOL MDMB
RVP bknd ' RVP ~olinc + BV RVP MDMB
VOL gasolinc ~ VOL MDMB VOL g~ c I VOL MDMB
Even though this equation is not 100% accurate for cal~ ting octane 0 numbers, as the RON and MON do not blend linearly, it can be used to predict octane withinil number for the n~low range of blends investig~te~l This example illustrates that the blçn-ling values for the properties of MDMB for the RON and MON are somewhat higher with an average of 110 and 97 respectively, and the RVP is somewhat lower at 6.9 kPa (1 psi), which iS typical, as co~ 3ared to the colll~ollent values for the RON, MON, and RVP of the MDMB component, which were 108, 97, and 7.3 kPa (1.06 psi) respectively. Also shown for reference are the typical blen~ling values for 15% MTBE, 10% ethanol and 12% TAME.
~ 1~ '6 9 s~
COMPONENT RON BV MON BV RVP BV
MDMB with 112 98 Gasoline A
MDMB with 109 96 G~coline B
MTBE 117 98 8.4 ETHANOL llS 96 22 One can see that the blen~ling RON and MON values of MDMB are co...~ able to those of MTBE, ethanol, and TA~E, which makes MDMB
5 attractive as an octane booster for motor ~coline. MDMB's low blen~ling RVP value makes it espec~ y attractive as an octane booster in co...p~ o--to MTBE, cth~nol and TAME, as it does not carIy a high RVP debit ac is typically associated with the other octane boosters.
ADDITIVE
This invention relates to the use of one isomer of tertiary-hexyl methyl ether, which is 2-methoYy-2,3-dimethylbutane, as an octane booster in motor g~coline Generally, any component that has a research octane number over 105 and a motor octane number over 95 is considered to be an octane booster for use in motor gasoline. It is well known in the art that ethers 0 made from C4 and Cs oleffns are eYcelle.nt octane boosters. Methyl tertiary-butyl ether (MTBE) made from isobutene, a C4 olefin, has a research octane number (RON) of 118 and a motor octane number (MON) of 100; and tertiary-amyl methyl ether (TAME) pro~ ce~ from Cs olefins has a RON of 111 and a MON of 98 accordi.lg to Un7elm~n, Oil & Gas Journal, Volume 44, April 15, 1991.
It is also well known that these ethers have a higher octane booster number than their counterpart olefins. "Physical 1~O~ of Hydrocarbon and Non-Hydrocarbon Co~ ounds" ASTM data series publiG~tion DS 4B, 1991 states that the octane numbers for one of the parent olefins of TAME, 2-methyl-2-butene, is 97 for the RON and 82 for the MON. Ftherific~tion of this Cs olefin increases the octane numbers to 111 for the RON and 98 for the MON. While the art te~hes that ethers produced from C4 and Cs olefins are excellent octane boosters, it te~clles away from the use of ethers produced from C6 and heavier olefins.
For example, in Pescarollo et al.'s article, "Etherify light g7~colines"~
Hydrocarbon Proceccing, February 1993, pp 53-60, he states that " . . . ethers derived from C6 and heavier olefins do not cignifiç~ntly enh~n~ e octane over the parent olefins".
Also, US-A-4,193,770, and its equivalent, DE-A-2,854,250 (1979) 3 o te~hes that the octane numbers of the C6 ethers are no higher than those of the parent olefins mixed with the same amount of methanol. The blending octane numbers for tertiary-hexyl methyl ether which is pro~ ce~l from a C6 olefin are reported as being 100 for the RON and 90 for the MON, but no mention is made of any specific isomers, inrhlding 2-methoxy-2,3-dimethylbutane (MDMB). Hence, there is no recognition or te~ing that MD~IB is effective as an octane booster. The reported numbers serve to -2- ~ 17,'69~
teach away from investig~ting the performance of ether produced from C6 or C7 olefins.
This reference te~heS the importance of etherifying C4 and Cs olefins separately from each other bea~-se of the di~erelll re~ction kinetics.
5 Also stressed is the ~ol l~ce of keeping each of these fractions separate from the C6 olefin fraction, which forms tertiary hexyl methyl ether, ber~llse there is no prove~l.ent in octane rating as co...l ~red to the ethers from the C4 and Cs olefinc. The reference goes as far as saying that any reported increases in octane rating for ethers from C6 and q olefins, are "illusory".
See cohlmn 3, lines 5 to 13 and 26 to 37.
This reference sets up a major prejudice ~e~inct using C6 ethers as motor gasoline octane boosters. And there is absolutely no m~ntion of MDMB.
MICROLOG-88-03391 from Energy Res. Abstr., 13(22), Abstr. No.
5031, 1988, also te~hes against the use of ethers prod~lced from C6 olefins in that "pre~lictiQnC for C6 ethers were not carried out bec~l~ce there was virtually no .. l,love"lent in octane number when co...p~red with its precursors".
EP-A-0 036 260, tlicrloses the use of ethers prod-lced from a ~i~.lule 20 of C4 through q olefins as components in a motor ~colin~ blend from a refinery catalytic cracker unit, with 7% being C6 olefinc, but lei"rorces the belief that the octane booster effect is due to the ethers prod~lced from C4 and Cs olefins rather than those ethers produced from C6 or q olefinc.
It would be desirable if ethers pro~ced from C6 olefins could be used 2 5 as motor octane boosters. Current market predictions indicate that there will be a glut of propylene, which could be used to make C6 olefins, in the market place within the next ten years. Currently, propylene is sent to the motor g~coline pool from refinery catalytic crackers, but the propylene does not boost the octane. It would be very profitable if one could determine a way to 3 0 coll~el l propylene into an octane booster.
SUMMARY OF THE INVENTION
This invention relates to using an octane boosting amount of a 35 tertiary hexyl methyl ether co",~onent col~ g 2-m~thc-Yy-2,3-dimethyl butane (MDMB) which enables providing a blend CO~ iSi~g (a) motor gasoline or motor gasoline feedstock; and (b) an octane boosting amount of a tertiary hexyl methyl ether component colllplish~g 2-methoxy-2,3-dimethyl butane (MDMB) in an ~mount of at least 10% by weight based on the total weight of tertiary hexyl methyl ether, wherein composition (b) has a Research Octane Number (RON) and/or a Motor Octane Number (MON) greater than those of co~ osilion (a).
One emboAim~-nt includes providing a blend wherein the tertiary hexyl methyl ether component of composition (b) colll~ lises in various 0 amounts and ranges, inrlllding, greater than 10%, preferably from 20 to 100~, more preferably greater than 50%, even more yrcferably from 60~o to 100%, and most prefe~bly greater than 80% by weight of MDMB.
Another embodiment inrllldes providing a blend wherein coLu~osilion (b) co.~ greater than 50%, preferably from 60% to 100%, and more 15 l,refe~ably greater than 80%, by weight of the tertiary hexyl methyl ether.
Yet another emboAiment inçl~ldes providing a method of increasing the octane number in motor g~coline collll,lishlg blending MDMB with the motor gasoline or with a motor g~coline feedstock to boost the octane number of the motor g~coline or motor g~colin~. feedstock which co~ a 2 o sufficient ~mollnt of composition (b) to boost the octane number of co..l~ullent (a) by at least 1, l,lcfeldbly by at least 2, and more prefelably by at least 3 units.
Still another emboAim~nt inrllldes the use of a tertiary hexyl methyl ether co-llpûllcnt co...l-t;~ing MDMB and having a blending RON greater than 100 and a ble-nAin~ MON greater than 90, as an octane booster for motor ~coline The tertiary hexyl methyl ether component co~ lisillg MDMB may be ~rcpared by dimerizing propylenes and ~d(lition~l emboAim~o.ntc of the present invention in~ de a blend wherein composition (b) is made by a process cOlll~lisillg:
(i) dimerizing propylene to form dimethylbutenes; and (ii) etherifying the dimethyl butenes with meth~nol, to form the desired col~o~ilion and/or a blend.
~AAition~lly, another embo~liment inÇllldec the funher tre?~tment wherein step (ii) comprises panial etherifiç~tion and is followed by (iii) ~ 17 '76q55 hydrogen~ti-n of unetherified dimethylbutenes to form a tertiary hexyl methyl ether composition COlll~liSillg MDMB and dimethyl butanes.
DETAILED DESCRIPIION OF THE INVENTION
Not all of the isomers of tertiary-hexyl methyl ether produced from C6 olefins are suitable for use as octane boosters. The four isomers of tertiary-hexyl methyl ether (C6 H13-OCH3) are as follows:
1) 2-Methoxy-2,3-dimethylbutane(MDMB) 2) 2-Methoxy-2-methylpent~ne (2MMP) I
I
3) 3-Methoxy-3-methylpentane (3MMP) I
I
2 1 78~55 4) l-Methoxy-l-methylcyclopentane (MMCP) I
CH2 /cH2 C
l-Metboxy-l-methylcyclopentane (MMCP) is conci~lered an isomer of tertiary-hexyl-methyl ether even though it has two fewer hydrogen atoms.
One isomer of tertiary-hexyl methyl ether has been found to be a very useful high octane booster for use in motor g~coline~ That particular isomer 15 is 2-methoxy-2,3-dimethylbutane (MDMB).
MDMB may be ~epared from propylene and methanol by first llim~ri7ing the propylene to dimethylbutenes (2,3-dimethyl)-(1 and/or 2)-butene), and then by ethe~ i-lg the dimethylbutenes with meth~nol, as shown in the following reaction equationc Both 2,3-dimethyl-1-butene and 20 2,3-dimethyl-2-butene react with methanol to form the desired product ether.
2 CH3CH = CH2 ~ CH3--CH- C = CH2 propylene 2,3-dimethyl-1-butene CH3--CH - C = CH2 + CH30H ~ CH3--CH - C--OCH3 3 o 2,3-dimethyl-1-butene methanol (DMB) CH3 2-methoxy-2,3-dimethylbutane 3 5 (MDMB) ,~17~q~5 Olefin dimerization and codimerization processes are known in the art. The propylene may be dimerized to dimethylbutenes (DMB) using a tnng~ten catalyst, such as that tli~rlose~ in U.S. Patent 5,059,739. The dimethylbutenes (DMB) may also be produced using nickel with specific organo-phosphine lig~n~l~
In the event, the tun~cte~ catalyst is used, the ratio of olefin to tungsten should be such that a catalytic amount of the tnn~tçn complex is used. The reaction may be run in either a batch or a co,-l;.,llous manner.
The re~çtion ~res~ule is normally the p'es~ulc generated by the olefin at the reaction tempeldlule, ~lth~lgh the ple~ulc may be increased with an inert gas. The re~ction temperature may range, for eY~mple, from about 40 to 100~C, with 50 to 80~C being preferred. The reaction or resi~len~e time may be, for example, from S min~ltes to about 3 hours, with 0.5 to 2.0 hours being preferred. The preferred embodiment uses a catalyst which is prepared by taking a tungsten salt and an aniline to form a complex of the t~mgstçn salt and ~niline S~1bst~nti~lly all of the hydrogen chloride pro~l~lce~l in this re~ction is removed from the sol~ltion during the course of the re~ction After form~tion of the tlmgstçn and aniline complex, an alkyl ~ ",;n~", halide is added to the sohltion to form the active catalyst system of the invention. The l,refelled feedstock is refinery grade propylene, after sufficient removal of water and other catalyst poisons.
The etherific~tion of the dimethylbutenes with meth~nol to prcpare MDMB may take place in a m~nner similar to the ~lepalalion of methyl tertiaIg-butyl ether (MTBE) from isobutylene or the preparation of tertiary-amyl methyl ether (TAME) from isoamylenes. The re~ o~ takes place over the acid form of an ion eY-~h~nge resin.
The present invention involves the feeding of a llli,LIure conl~ g DMB and methanol into the feed zone of a reactor (i.e., a fixed-bed guard reactor), and cont~cting the reslllt~ns ll~ lure of DMB and methanol with a fixed bed acidic cation exchange resin (e.g., Amberlys~) 15) in the reaction zone, thereby catalytically re~cting the DMB with the methanol under conditions which favor forming the res~llt~nt 2-methoxy-2,3-dimethylbutane (MDMB).
Where the etherification step of the present invention is practiced in a catalytic ~ till~tion process, the catalytic material may be in any form which WO 95/16763 2 ~ 7 8 9 5 5 PCT/USg4/1423~
pcllllils its incorporation into a tlictill~tion tower, such as a fixed bed, butmay also be in a form which serves as a di~till~tion p~ing, for example, rings, s~ lles, balls, irregular pieces, sheets, tubes, spirals, packed in bags,plated on grills or screens, and reticlll~ted polymer foams.
Catalysts which have been found to be suitable for use in the etherification step of the present invention are resin catalysts such as cation h~e resin catalysts, acidic resin catalysts, macroreticular s~llfonic acid cation eYrh~nge resin catalysts, and solid acid catalysts. Still others have used a zeolite as an etherific~fion catalyst. Preferred catalysts for purposes of thepresent invention, however, are acid catalysts, such as acidic resin catalysts.
A more ~refelled catalyst for purposes of the present invention is a macroreticular sulfonic acid cation eYrh~n~e resin such as a slllfon~te~
copolymer of poly~lylelle-divinyl-ben7ene. Such catalysts inrlude Amberlyst t!~) 15 and 15C (m~rkçted by Rohm and Haas), Lewatit SPC 118 and SPC 118 BG (marketed by Miles/Bayer), and Dowex M-31 and M-32 (marketed by the Dow Chemical Co.). A special version of this type of catalyst, i.e., Dowex DR-2040 (marketed by the Dow Ch~mic~l Co.), is used specifi~lly for reactive dict~ tinn It has been found that eqllilibrinm co--vel~ion to ether is only 50-60%, so it is expected that catalytic tlictill~tion will be advantageous in the etherific~fion step. Catalytic dictill~tion is commercially pr~ ticed in the prodllction of MTBE and this process has been extensively explored with TAME. Therefore, there is every reason to expect that catalytic ~icfill~tion would be advaIltageous when applied to the process for producing ethers from C6 olefinc.
When the ether is pro~l~lce~ from a C6 olefin which has been formed by ~im~ri~in~ propylene, the co---~osilion of the reslllting ~-~lu e of isomers may be as pure as 98 wt% MDMB, 2 wt% 2MMP, with n~ligihle amounts of 3MMP and MMCP. When the C6 olefin is pro~ ed in a refineIy catalytic cracker, the isomer ll~ ule is di~ere--l, with more than 50% being 2MMP
and ~plo~;...~tely 7% being MDMB.
It is well known in the art that ethers are used as motor E~coline additives to enh~nce the quality of the motor gasoline due to el-viro.. ent~l regulations, both eYictin~ and pending in the USA. By using an oxygenate 35 rather than its counter part olefin in motor gasoline, less carbon monoYide pollution is produced upon combustion of the motor g~coline Also, the rules ~17 ~q5~
re~ ting reformnl~ted ~coline which is a particular type of motor ~coline, require that a lower olefin content be present in the g~coline due to the fact that olefins contribute to ozone formation more than their counter part ethers. An ~d~liti~n~l advantage of using the ether rather than the olefin in 5 motor g~coline is that the ether has a lower Reid vapor pl~s~ulc, which reduces evaporative emiccionc which contribute to pollution.
The ~d~lition of the MDMB to the motor e~colinP, or motor ~colinP, feedstock to boost the octane may be ~ccomplished in several ways. One method includes the preparation of a blend C(illlpliSillg the ll~lure of two 0 compositions, (a) and (b), wherein composition (a) cO.~;cl~ of the motor ~colinP, or motor &~coline feedstock which is blended with colllposilion (b) which colll~lises an octane boosting amount of a tertiary hexyl methyl ether collll,ollent comprising 2-mPthoYy-2,3-dimethyl butane (MDMB) in an ~mollnt of at least 10% by weight based on the total weight of tertiary hexyl 15 methyl ether, wherein the colll~osilion (b) has a Research Octane Number (RON) and/or a Motor Octane Number (MON) greater than those of colll~osilion (a).
In ~d~lition to the tertiary hexyl methyl ethers and the MDMB, co,l.posilion (b) may inrhlde other colll~ ne~b. These ~ ition~
20 colll~ollents may be any other hydroc~l.ol~s typically found in motor g~colin~
or motor g~colin~ fee~lctocl~c~ inrlu~ling, but not limited to, aro...s~;rc, olefinc, and saturates.
These ~d(lition~l hydrocarbons may or may not be cqncidered useful as octane boosters. In the case where the other hydroc~l,olls are useful as octane boosters, composition (b) may inclucle either MTBE or TAME, or n~i~lures thereof.
Co~ osilion (b) may have a RON greater than 95, preferably greater than 100, and/or a MON greater than 85, ~refel~bly greater than 90.
Optionally composition (b) has a blen~ling RON greater than 100, ~le~lably greater than 105 and/or a blen~lin~ MON greater than 90, prefelably greater than 9S.
The tertiary hexyl methyl ether colll~onent of col,l~osilion (b) may col~lise greater than 10%, prefelably from 20 to 100%, by weight of MDMB. Optionally, this tertiary hexyl methyl ether collll~onent of co~ osilion (b) may co~ lise from 50 to 100%, l,lerel~bly greater than 80%, by weight of MDMB.
The tertiary hexyl methyl ether component may have a RON greater than 100 and/or a MON greater than 90. Optionally, this tertiary hexyl methyl ether component may have a blending RON greater than 100 and/or a blen~ling MON greater than 90.
The MDMB component of co"",osilion (b) may have a RON greater than 105 and/or a MON greater than 95. Optionally, the MDMB component may have a blen~ling RON greater than 105 and/or a blen-ling MON greater than 9S.
The resultin~ blend may have a RON greater than 90, l"~felably 0 greater than 93, and/or a MON greater than 80, preferably greater than 83.
A sufficient amount of composition (b) must be blended with co".~osilion (a) such that the octane number of component (a) is boosted by at least 1, preferably by at least 2, and more prefelably by at least 3 units.
The resnlting blend may which comprise greater than 1%, preferably greater than 2%, and most preferably greater than 5%, by volume of MDMB.
In addition to its use as an octane booster, MDMB has the added benefit of not significantly increasing the RVP of the motor g~coline blend as is typical with other octane boosters, such as MTBE or TAME.
For example, MTBE has a blçn~ling RVP of 57.9 kPa (8.4 psi) and TAME has a blending RVP of 27.6 kPa (4.0 psi), both of which are higher than that of MDMB being 6.9 kPa (1 psi).
When the starting motor g~coline fee~lctQck has a high RVP level, one could be limited on how much MTBE or TAME ~d~lition is possible to achieve the required octane requirçm~-ntc, while at the same time, not ~Y~eetling the RVP limit.
Therefore, an additional embo~imçnt of the present invention inl~hldes the use of more than one octane booster to achieve the ",~xi, octane boosting effect and without the co"esponding undesirable increase in RVP.
For example, one could make a blend COl"~,iSi"g the ~ddition of MTBE and/or TAME up to the m~x;...,.... RVP limit of the motor g~colin~
product as set by an el,viro.~..ent~l st~nd~rd. Then, MDMP, either alone or in llli~ure with the tertiary hexyl methyl ether, could be blended into the motor ~coline to achieve on even higher octane number without incurring 35 any increase in the RVP of the final blend of motor ~coline.
~ 1 7 ~ ~5~
One embo~lim~nt of the invention inr~ es a blend which cont~inc a sufficient amount of composition (b) to boost the octane number of co~ ,onent (a) by at least 1, while at the same time increasing the Reid vapor plcs~urc of component (a) by less than 13.8 kPa (2 psi), preferably by less than 6.9 kPa (1 psi), and more preferably by less than 3.4 kPa (0.5 psi).
The MDMB may be preparcd using a process colllplising (i) ~limeri7ing propylene to form dimethylbutenes and (ii) etherifying the dimethyl butenes with methanol. Optionally, wherein step (ii) colll~lises partial etherification, the process may further col~ lise the ~ ion~l step of 0 (iii) hydrogen~tion of the unetherified dimethylbutenes to form a tertiary hexyl methyl ether composition COlll~liSillg MDMB and dimethyl butanes.
Co~ .osilion (b) may co..l;l;.. dimethylbutenes and may also cont~in less than 1% meth~nol and/or less than 5% olefinc Composition (b) may co~ greater than 50%, ~rcferably from 60% to 100%, and more 15 l,refelably greater than 80%, by weight of the tertiary hexyl methyl ether.
By ble-n~ling the pre~ared MDMB, with a motor g~coline or motor g~coline feedstock, the octane number of the blended ~coline may be increased by 1 or more units, prcfe~ably 2 or more units, and most preferably 3 or more units, over the original octane number of the motor gasoline or 20 motor g~coline feedstock.
The foregoing invention will now be illustrated by, ~lthollgh not limited to, the following examples.
EXAMPLES
EXAMPLE I
2-MMP Col-lpa~alivc Example This co..~p~ativc example illustrates that not all ethers prodllce-l from 3 C6 olefins are useful as octane boosters.
An ion eY~ h~nge resin in the acid form (Amberlyst R15, washed with methanol) was added to a 5000 mL round-bottom _ask along with 1000 g of 2-methyl-1-pentene and 416 g methanol. The slurry of resin catalyst was stirred magnetically and reflmre~ at ~tmospheric pressure for 16 hours. In 35 the relll-x;--g process, the material boils at ~tmospheric prcssule and conde-ncec the vapors back into the boiling material. The resin catalyst was WO 95/16763 2 ~ 7 8 9 5 5 PCT/USg4/14234 filtered from the product lllL~Iure, and then uncollvelled methanol and methyl pente-nes were distilled away from the product ether (2MMP). The uncollvelled materials were placed back in the re~ction flask with the resin catalyst and refluxed again for another 16 hours. This procedure of reaction s followed by removal of product ether was repe~te~l three times. This was desirable in order to achieve good collvel~ion of the starting material since the etherific~tion re~ction is equilibrium limite~l The product ether was distilled again (boiling point 112~C) to yield product purity of 99.4% by GC
analysis.
0 The octane numbers and Reid vapor ~les~ure results were mç~cllred using the st~n~l~rd test methods well known in the art. The Research Octane Number (RON) was 88.3 and the Motor Octane Number (MON) was a~rc.-;...~tçly 90. The precise MON could not be ~p~cl~ed as the fuel/air ratio was set at the hiehest setting available on the test eneine~ In the st~n(l~rd test procedure, the fuel/air ratio is co~ lly increased until m~x;.",),- knock is obtained. The Reid vapor plcs~ure was 1.25 psi.
These results are concictent with the reported octane numbers for ethers of C6 olefinc, and support the industry view (for example, as e,-~fessed in US-A~,193,770) that such ethers are not useful as octane boosters for 2 o motor ~colinç~
EXAMPLE II
MDMB - the Invention This example of the invention illustrates that one of the ethers pro~h~ce~ from C6 olçfinc, spe~fic~lly MDMB, is useful as an octane booster.
2-Methoxy-2,3-dimethyl butane (MDMB) was ~ ed from 2,3-dimethyl-2-butene (2112 g) and methanol (879 g) in a similar m~nnçr as described for prepa~ation of 2MMP in Example I. The product had a boiling point of 115C and a product purity of 98.2% 2-methoxy-2,3-dimethylbutane with the balance being 2-methoxy-2-methyl pentane from 2-methylpentene h~ulil~ in the starting material. The Research Octane Number mç~cllred for this MDMB rich product was 108.1 and the Motor Octane Number was 96.8. The Reid vapor ~res~ule was 7.3 kPa (1.06 psi).
- 12- ~ q 5 Analysis of Examples I and II
The octane numbers from Examples I and II along with those of C4 and Cs olefins are reproduced below in a table format for easy co,.,r ~ on Parent Olefin Ether RON MON
C~ TAME 111 98 C6 MDMB 108.1 96.8 2MMP 88.3 less than 90 One can see that unexpectedly, and con~ to the prejudice arising from the prior art investig~tion of C6 olefin ether, MDMB has RON and MON values which _ake it sul~ gly good as an octane booster for motor g?~colin EX~MPLE III
In ~d~lition to the coJl,l)o"ent RON, MON, and Reid vapor l,le~uie (RVP) numbers being determined, a set of col,esponding blen~ling values for 5 MDMB was also ascertained. As it is well known to one of ordi"a,~ skill in the art, the "blen~ling" RON, MON, and RVP values vary based upon the base g~coline composition- Typically, the "Blending Values" (BV) are higher for RON and MON and are slightly lower for RVP.
Blends of appro-;",~tely 14, 19, and 25% volume MDMB/volume 20 g~colinet as synthe-ci7e~l in Example II, were plepared using two diL~ere, g~colin.os, A and B, as described below.
Gasoline AG~coline B
RVP, kPa 50.3 (7.3 psi)53.8 (7.8 psi) The res~llting RON, MON, and Reid vapor pres~ure numbers were 25 me~c~lred for each of the blends with the following results.
Gasoline MDMB RON MON RVP RVP
Vol %Blend Blend Blend, Blend, kPa psi A 13.895.6 85.2 45.5 6.6 A 18.796.3 85.8 43.4 6.3 A 24.397.3 87.0 37.9 5.5 Average A ~ 96.4 86.0 42.1 6.1 B 14.298.8 88.2 42.7 6.2 B 19.299.4 88.8 46.2 6.7 B 24.999.9 89.6 40.7 5.9 AverageB --- 99.4 88.7 43.4 6.3 The values of the blend were then used in the following m~nner to c~ te the l,lopellies of the finiche~ blend. RVP is used as an example.
VOL ga~ e VOL MDMB
RVP bknd ' RVP ~olinc + BV RVP MDMB
VOL gasolinc ~ VOL MDMB VOL g~ c I VOL MDMB
Even though this equation is not 100% accurate for cal~ ting octane 0 numbers, as the RON and MON do not blend linearly, it can be used to predict octane withinil number for the n~low range of blends investig~te~l This example illustrates that the blçn-ling values for the properties of MDMB for the RON and MON are somewhat higher with an average of 110 and 97 respectively, and the RVP is somewhat lower at 6.9 kPa (1 psi), which iS typical, as co~ 3ared to the colll~ollent values for the RON, MON, and RVP of the MDMB component, which were 108, 97, and 7.3 kPa (1.06 psi) respectively. Also shown for reference are the typical blen~ling values for 15% MTBE, 10% ethanol and 12% TAME.
~ 1~ '6 9 s~
COMPONENT RON BV MON BV RVP BV
MDMB with 112 98 Gasoline A
MDMB with 109 96 G~coline B
MTBE 117 98 8.4 ETHANOL llS 96 22 One can see that the blen~ling RON and MON values of MDMB are co...~ able to those of MTBE, ethanol, and TA~E, which makes MDMB
5 attractive as an octane booster for motor ~coline. MDMB's low blen~ling RVP value makes it espec~ y attractive as an octane booster in co...p~ o--to MTBE, cth~nol and TAME, as it does not carIy a high RVP debit ac is typically associated with the other octane boosters.
Claims (25)
1. A blend comprising (a) motor gasoline or motor gasoline feedstock; and (b) an octane boosting amount of a tertiary hexyl methyl ether component comprising 2-methoxy-2,3-dimethyl butane (MDMB) in an amount of at least 10% by weight based on the total weight of tertiary hexyl methyl ether, wherein the composition (b) has a Research Octane Number (RON) and/or a Motor Octane Number (MON) greater than those of composition (a).
2. A blend according to Claim 1, wherein the composition (b) has a RON greater than 95 and/or a MON greater than 85.
3. A blend according to Claim 1 or 2, wherein the composition (b) has a RON greater than 100 and/or a MON greater than 90.
4. A blend according to any of the preceding claims, wherein the composition (b) has a blending RON greater than 100 and/or a blending MON greater than 90.
5. A blend according to any preceding claim, wherein the composition (b) has a RON greater than 105 and/or a MON greater than 95.
6. A blend according to any of the preceding claims, wherein the tertiary hexyl methyl ether component of composition (b) comprises greater than 10%, preferably from 20 to 100%, by weight of MDMB.
7. A blend according to any of the preceding claims, wherein the tertiary hexyl methyl ether component of composition (b) comprises from 50 to 100%, preferably greater than 80%, by weight of MDMB.
8. A blend according to any of the preceding claims, wherein the tertiary hexyl methyl ether component has a RON greater than 100 and/or a MON greater than 90.
9. A blend according to any of the preceding claims, wherein the tertiary hexyl methyl ether component has a blending RON greater than 100 and/or a blending MON greater than 90.
10. A blend according to any of the preceding claims, wherein the MDMB
component has a RON greater than 105 and/or a MON greater than 95.
component has a RON greater than 105 and/or a MON greater than 95.
11. A blend according to any of the preceding claims, wherein the MDMB
component has a blending RON greater than 105 and/or a blending MON greater than 95.
component has a blending RON greater than 105 and/or a blending MON greater than 95.
12. A blend according to any of the preceding claims, wherein the blend has a RON greater than 90 and/or a MON greater than 80.
13. A blend according to any of the preceding claims, wherein the blend has a RON greater than 93 and/or a MON greater than 83.
14. A blend according to any of the preceding claims, which contains a sufficient amount of composition (b) to boost the octane number of component (a) by at least 1, preferably by at least 2, and more preferably by at least 3 units.
15. A blend according to any of the preceding claims, which comprises greater than 1%, preferably greater than 2%, and most preferably greater than 5%, by volume of MDMB.
16. A blend according to any of the preceding claims, wherein composition (b) is made by a process comprising:
(i) dimerizing propylene to form dimethylbutenes;
and (ii) etherifying the dimethyl butenes with methanol, to form the desired composition.
(i) dimerizing propylene to form dimethylbutenes;
and (ii) etherifying the dimethyl butenes with methanol, to form the desired composition.
17. A blend according to Claim 16, wherein step (ii) comprises partial etherification and is followed by (iii) hydrogenation of unetherified dimethylbutenes to form a tertiary hexyl methyl ether composition comprising MDMB
and dimethyl butanes.
and dimethyl butanes.
18. A blend according to any preceding claim, wherein composition (b) also contains dimethylbutenes.
19. A blend according to any preceding claim, wherein composition (b) also contains less than 1% methanol.
20. A blend according to any preceding claim, wherein composition (b) also contains less than 5% olefins.
21. A blend according to any preceding claim, wherein composition (b) contains greater than 50%, preferably from 60% to 100%, and more preferably greater than 80%, by weight of the tertiary hexyl methyl ether.
22. A blend according to any of the preceding claims, which contains a sufficient amount of composition (b) to boost the octane number of component (a) by at least 1 unit, while at the same time increasing the Reid vapor pressure of component (a) by less than 13.8 kPa (2 psi), preferably by less than 6.9 kPa (1 psi), and more preferably by less than 3.4 kPa (0.5 psi).
23. The use of a tertiary hexyl methyl ether component comprising MDMB in an amount of at least 10% by weight based on the total weight of tertiary hexyl methyl ether component and having a blending RON greater than 100 and a blending MON greater than 90, as an octane booster for motor gasoline.
24. The use of a tertiary hexyl methyl ether component comprising MDMB in an amount of at least 10% by weight based on the total weight of tertiary hexyl methyl ether component, as an octane booster for motor gasoline wherein the blending RON and/or the blending MON of the tertiary hexyl methyl ether component is higher than the RON and/or MON of the untreated motor gasoline.
25. The use of a tertiary hexyl methyl ether component in accordance with Claim 23 or 24, wherein the Reid vapor pressure of the treated motor gasoline is higher by less than 13.8 kPa (2 psi), preferably by less than 6.9 kPa (1 psi), and more preferably by less than 3.4 kPa (0.5 psi).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16739093A | 1993-12-15 | 1993-12-15 | |
| US167,390 | 1993-12-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2178955A1 true CA2178955A1 (en) | 1995-06-22 |
Family
ID=22607182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002178955A Abandoned CA2178955A1 (en) | 1993-12-15 | 1994-12-13 | Use of tertiary-hexyl methyl ether as a motor gasoline additive |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0734429B1 (en) |
| JP (1) | JPH09506660A (en) |
| AU (1) | AU685564B2 (en) |
| CA (1) | CA2178955A1 (en) |
| DE (1) | DE69427133T2 (en) |
| SG (1) | SG67335A1 (en) |
| WO (1) | WO1995016763A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001007539A1 (en) * | 1999-07-21 | 2001-02-01 | Exxon Chemical Patents Inc. | Ethers with low water solubility used in liquid fuels |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3163813D1 (en) * | 1980-03-07 | 1984-07-05 | British Petroleum Co Plc | Preparation of a motor spirit blending component |
| US4519809A (en) * | 1984-04-23 | 1985-05-28 | Exxon Research & Engineering Co. | Method for reducing water sensitivity of ether containing gasoline compositions |
| US4746761A (en) * | 1986-07-18 | 1988-05-24 | Mobil Oil Corporation | Process for coverting methanol to alkyl ethers |
| US4886925A (en) * | 1988-05-02 | 1989-12-12 | Mobil Oil Corp | Olefins interconversion and etherification process |
-
1994
- 1994-12-13 DE DE69427133T patent/DE69427133T2/en not_active Expired - Fee Related
- 1994-12-13 JP JP7516874A patent/JPH09506660A/en active Pending
- 1994-12-13 EP EP95904872A patent/EP0734429B1/en not_active Expired - Lifetime
- 1994-12-13 AU AU13387/95A patent/AU685564B2/en not_active Ceased
- 1994-12-13 SG SG1996007133A patent/SG67335A1/en unknown
- 1994-12-13 CA CA002178955A patent/CA2178955A1/en not_active Abandoned
- 1994-12-13 WO PCT/US1994/014234 patent/WO1995016763A1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| EP0734429A1 (en) | 1996-10-02 |
| JPH09506660A (en) | 1997-06-30 |
| EP0734429B1 (en) | 2001-04-18 |
| DE69427133D1 (en) | 2001-05-23 |
| WO1995016763A1 (en) | 1995-06-22 |
| DE69427133T2 (en) | 2001-10-18 |
| SG67335A1 (en) | 1999-09-21 |
| AU1338795A (en) | 1995-07-03 |
| AU685564B2 (en) | 1998-01-22 |
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