Gasoline Containing A Methyl Phenol And An Ether

Abstract

A useful fuel for an internal combustion engine comprises a hydrocarbon base stock of gasoline boiling range, a methyl-substituted phenol and an ether containing a branched alkyl group and boiling below 460.degree.F., said phenol and said ether each being present in amount (e.g., 0.1-15 wt. %) sufficient to increase the Research octane number (RON). The invention also includes a gasoline blending system. For example, preferred compositions can be made by blending 89 RON gasoline containing 5 vol. % p-cresol with 97 RON gasoline containing 5% methyl methoxy propane. Beneficial synergism is noted in such blends for RON blending values.

Description

SUMMARY OF THE INVENTION

The invention includes a novel gasoline blending system, the use of this system to produce motor fuel of improved octane rating, and novel gasoline compositions containing certain phenols and ethers.

One embodiment is gasoline comprising a hydrocarbon base stock of gasoline boiling range, a methyl substituted phenol and an ether having at least one branched alkyl group and boiling below 460.degree.F., said phenol and said ether each being present in amount sufficient to increase the Research octane number.

Another embodiment is a gasoline blending system comprising a supply of a relatively high Research octane number gasoline containing an octane improving amount of an ether boiling below 460.degree.F., and a supply of a relatively low Research octane number gasoline containing an octane improving amount of a methyl substituted phenol boiling below about 460.degree.F., and means for blending said two supplies to produce gasolines having octane numbers intermediate to those of said high and low octane number gasolines.

The preferred methyl substituted phenols include the cresols (e.g., p-cresol), the xylenols (e.g., 2,3 dimethyl phenol) and the trimethyl-substituted phenols (e.g., hydroxy pseudocumene, hydroxy mesetylene, and hemimelitol) and mixtures of such phenols, with the cresols being the preferred additives to a low RON hydrocarbon base stock in our blending system where the high RON hydrocarbon base contains an ether additive.

The preferred ethers comprise the dialkyl ethers wherein at least one alkyl group is branched, and include diisopropyl ether, diisobutyl ether, methyl isopentyl ether, methyl isopropyl ether, and mixtures of two or more said ethers. Phenyl alkyl ethers can also be used (e.g., isopropyl phenyl ether). One non-branched alkyl phenyl ether, methyl phenyl ether (methoxy benzene) can be used in a gasoline containing a methyl phenol or as the ether in the blending system described herein.

The ethers and phenols which can be used in our invention include those described by G. H. Unzdman, E. J. Forster and A. M. Burns, in API Preprint (Div. of Refining) No. 47-71, titled "Are There Substitutes for Lead Antiknocks?," presented at the API Meeting in San Francisco, May 14, 1971.

Generally, the amount of the ether can be in the range of 0.05-30% and the amount of the phenol in the range of 0.05-35% (the limit being determined by solubility); however, the preferred amounts are in the range of 0.1-15%. More preferred, the phenol is in the range of 0.5-10 wt. % and the total of said amounts is in the range of 1-15 wt. %.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying FIGS. 1 and 2 illustrate the beneficial synergistic effect on research octane blending and motor octane blending values which can be obtained by practice of the blending system of the present invention wherein the low RON gasoline contains p-cresol and the high RON gasoline contains methyl methoxy propane.

As is described in more detail hereinafter, the data for FIGS. 1 and 2 were obtained with gasoline base stocks of slightly different composition and are presented for purposes of illustration. If desired, the data in Table 2 herein can be plotted, in a manner similar to FIG. 1, to provide a comparison of RON and MON blending values for the same gasoline bases.

FURTHER DESCRIPTION

In a preferred blending system the low RON gasoline contains a cresol (or mixture of cresols) and preferably contains p-cresol (typically, 1-15 wt. %, more preferred 2-10 wt. %) and the high RON gasoline contains methyl tertiary butyl ether, methyl methoxy propane (MMOP), typically 1-20 wt. %, more preferred 2-15 wt. % (e.g., 7%).

The gasolines can also contain a lead antiknock (e.g., 0.1-4 cc. TEL/gal), a lead scavenger (e.g., organo bromides, ethylene dichloride), deposit modifiers (e.g., boron and phosphorous compounds), lower acyclic alcohols (e.g., methanol, ethanol, isopropanol, butanol, etc.), a lead appreciator (e.g., t-butylacetate), oxidation inhibitors (e.g., aromatic amines and/or alkyl phenols, such as 2,6-di-t-butyl-p-cresol), metal deactivators (e.g., NN'-disalicylidene-1,2-propylene diamine), corrosion inhibitors (e.g., high molecular weight phosphoric, carboxylic or sulfonic acids or their reaction products with nitrogen bases, such as amines, and include "Ethyl MPA"), antistatic additives (e.g., "Shell ASA-3") and anti-icing additives (e.g, methylcellosolve and glycerol). Some of these gasoline additives are described, for example, by J. P. Heuston, "Chemical Additives in Petroleum Fuels," S. African Ind. Chemist, 20:65-70, 74 (1966).

In our gasoline blending system, one or both of the gasolines can contain an acyclic alcohol containing in the range of 1-4 carbon atoms preferably the supply which contains the ether contains in the range of 1-15 wt. % of the alcohol. Such alcohols increase the RON of the gasolines.

In the blending system, on a lead free basis the high RON gasoline will typically have an RON in the range of 90-105 and the low RON gasoline will be at least 5 RON lower. However, where one or both gasolines contain a lead antiknock compound (such as mixed methyl and ethyl leads, e.g., dimethyl diethyl lead, etc.), the high RON gasoline can have an RON as high as 120 (the low RON gasoline being, typically, in the range of 75-90 RON).

In our blending system, typically, the hydrocarbon base of the high RON gasoline can contain in the range of 20-40% aromatics, 0-20% olefins, 0-10% naphthenes, with the balance being paraffins (the minimum paraffin content being 45%, more preferred 55%). The low RON gasoline can contain in the range of 15-40% aromatics, 0-25% olefins, 2-20% naphthenes, with the balance being paraffins, the minimum paraffin content being 35% (more preferred 45%).

In our preferred gasoline compositions, containing both the ether and phenol (such as the blends from our system), the preferred hydrocarbon base stock contains in the range of 40-75% paraffins, 0-10% naphthenes, 0-20% olefins and 20-40% aromatics. More preferred, the base stock will have an RON in the range of 80-100, and an MON in the range of 75-95. For the synergistic effect disclosed herein with p-cresol and MMOP, the preferred base stock contains in the range of 50-60% paraffins, 1-10% naphthenes, 2-10% olefins and 28-38% aromatics.

ILLUSTRATIVE EXAMPLES

EXAMPLE 1

Typical low Research octane rating and high Research octane rating hydrocarbon base stocks, in the gasoline boiling range, were obtained by blending selected refinery streams, including catalytically cracked gasoline, straight run gasoline, reformate, "aviation" alkylate, etc.

Table III reports the percentages by volume of paraffins, naphthenes, olefins and aromatics in these base stocks. Table IV reports in more detail on the composition of a "stabilized" sample of each blend stock.

Methyl methoxy propane (MMOP) was added, 5 wt. %, to a sample of the high RON base stock and p-cresol, 5 wt. %, was added to a sample of the low RON base stock.

A series of blends was made of various proportions of the high RON base with the low RON base and of the high RON base plus 5% MMOP with the low RON base plus 5% p-cresol.

Research octane ratings were obtained for each of the base stocks and blends. The significance of the blending value octane number and its method of calculation are described in U.S. Pat. No. 3,030,195, issued 4-17-62 to Evan B. Ewan. The blending value RON was then calculated for selected blends. The results of these tests and calculations are reported in Table I and are summarized by the curves in FIG. 1. A beneficial synergistic effect was noted for the RON blending values of the blends containing both p-cresol and MMOP.

There was an insufficient amount of the two hydrocarbon bases to permit testing for motor octane number (MON).

EXAMPLE 2

High and low RON hydrocarbon base stocks, in the gasoline boiling range, were obtained by blending the same types of selected refinery streams and in about the same proportions as in Example 1. Since the refinery streams were not identical to those used in the Example 1 bases, the chemical compositions and octane ratings were not the same as in Example 1, but represent the usual variation which is encountered in refining practice. 5 wt. % p-cresol was added to a sample of the low RON base and 5 wt. % MMOP was added to the high RON base. The two gasolines were blended as in Example 1 and both research (RON) and motor (MON) octane numbers were obtained. Research and motor blending values were calculated. Table II reports the results of these tests and calculations. Slight synergism (in comparison with Example 1) was noted in the RON blending values for some blends and greater synergism (but less than in Example 1) was noted for most blends in the MON blending values. FIG. 2 presents curves summarizing the results of the motor octane number testing of this example.

Table V attached hereto presents analyses of typical refinery streams which can be used to make hydrocarbon base stocks which can be used in the present invention. Table V also shows proportions for blending these streams to make a high RON and a low RON base which are particularly desirable in our blending system. The low RON base analyzes (in volume %), 40% paraffins, 7% naphthenes, 15% olefins and 38% aromatics. The high RON base contains 63% paraffins, 0% naphthenes, 3% olefins and 34% aromatics.

In gasoline for automobiles using conventional piston engines, it has been found that knocking under actual road conditions (or road octane) can be better correllated with a function such as R+M/2 or R+2M,/2, which combines RON (i.e., R) and MON (i.e., M), than with either RON or MON. Therefore, it is apparent that both of the previous examples indicate that the present blending system and gasolines can provide improved performance in an automobile under actual road conditions.

Among the cresols, the ortho and meta isomers are less preferred in gasoline than p-cresol. That is, paracresol has higher research and motor octane blending values (and lower sensitivity) than the other isomers. Each of these isomers can absorb (or dissolve) in the order of 2 wt. % water and, with about 15 wt. % cresols in gasoline the water solubility is about 0.5 wt %. If this amount of water is added to the gasoline, it reduces flame temperature and, thus, the NOx (nitrogen oxides) emission and increases the power output of the engine.

TABLE I __________________________________________________________________________ p-CRESOL AND METHYL t-BUTYL ETHER IN GASOLINE BLENDS __________________________________________________________________________ Base Composition (Volume %) RUN A B C D E F G H Low RON Base Stock + 5% Wt. p-Cresol 100 -- 85.7 71.4 57.1 42.9 28.6 14.3 High RON Base Stock + 5% Wt. MMOP -- 100 14.3 28.6 42.9 57.1 71.4 85.7 Research, F-1 Clear Duplicates 89.0 97.8 90.4 91.6 93.0 94.6 95.6 97.0 89.1 97.8 90.6 91.8 93.0 94.6 95.6 96.8 Average 89.05 97.8 90.5 91.7 93.0 94.6 95.6 96.9 A' B' C' D' E' F' G' H' Low RON Base Stock 100 -- 85.7 71.4 57.1 42.9 28.6 14.3 High RON -Base Stock -- 100 14.3 28.6 42.9 57.1 71.4 85.7 Research, F-1 Clear Duplicates 83.6 96.3 85.2 87.0 88.9 90.3 92.0 93.6 83.8 92.2 85.4 87.0 88.8 90.4 92.0 93.6 Average 83.7 96.25 85.3 87.0 88.85 90.35 92.0 93.6 Increased RON 5.35 1.55 5.20 4.70 4.15 4.25 3.60 3.30 Blending Value RON 191 127 189 181 172 175 164 160 __________________________________________________________________________ ##SPC1##

TABLE III ______________________________________ GASOLINE COMPOSITION (VOLUME PERCENT) Blends (Base Stocks) Low RON High RON ______________________________________ Paraffins 55 58 Naphthenes 9 6 Olefins 10 4 Aromatics 26 32 TOTAL 100 100 Research Octane No. (RON) 85 95 Motor Octane No. (MON) 78 85 ______________________________________

TABLE IV ______________________________________ STABILIZED* GASOLINE COMPOSITION (VOLUME PERCENT) Base Stock Low RON High RON ______________________________________ Paraffins 50.9 59.7 Paraffins 50.9 59.7 Naphthenes 9.5 2.0 Monocyclic paraffins 8.8 1.9 di-cyclic paraffins 0.6 0.1 tri-cyclic paraffins 0.1 0 Olefins 9.6 3.7 Aliphatic monoolefins 7.6 3.2 Cyclic monoolefins 2.0 0.5 Aromatics 30.2 34.6 (Alkyl Benzenes) (29.2) (34.4) Benzene 1.1 0.5 Toluene 5.5 15.8 C.sub.8 's 10.0 10.0 C.sub.9 's 8.0 5.6 C.sub.10 's 3.6 2.1 C.sub.11 's 1.0 0.4 (Alkyl Naphthalene) (1.0) (0.2) Naphthalene 0.5 0.2 Methyl naphthalene 0.5 0.0 TOTAL 100.2 100.0 ______________________________________ * Stabilized by distillation to remove components boiling below 100.degree.F.

TABLE V __________________________________________________________________________ Base Stock Vol.% Component Refinery Analysis (Vol. % of Component) Low High Component Paraffins Naphthenes Olefins Aromatics RON RON __________________________________________________________________________ Alkyl benzenes* 100 11.0 Reformate 35.2 0.6 0.1 64.1 10.6 25.8 Catalytic Gasoline 11.9 8.0 20.3 59.8 63.4 Straight Run Gaso. 55.8 33.2 1.2 9.8 2.5 Isopentane 100 12.1 7.4 Isomerizate** 89.8 10.2 0.8 Alkylate 98.0 2.0 1.8 40.6 Poly Gasoline 100 0.3 2.1 Udex Raffinate 86.8 6.4 3.6 3.2 1.0 Butanes*** 7.5 13.1 __________________________________________________________________________ * Typically bottoms from toluene manufacture, containing mostly xylenes (typically 50-80%) and toluene (typically 5-30%), remainder (e.g., 5-15%) being other alkyl benzenes (up to C.sub.11). ** Product of hydroisomerization of refinery streams which contain normal paraffins (e.g., Udex raffinate). ***The proportion of the butane component can be varied to obtain the desired Reid Vapor Pressure (typically in the range of 9-15 psi). Propane can also be present in winter gasoline.

Claims

The invention claimed is:

1. Gasoline comprising a hydrocarbon base stock of gasoline boiling range, from 0.05 to 35% of a methyl substituted phenol and from 0.05 to 30 % of a hydrocarbyl ether having at least one branched alkyl group and boiling below 460.degree.F., said phenol and said ether each being present in amount sufficient to increase the Research octane number.

2. Gasoline according to claim 1 and wherein the amounts of said phenol and said ether are in the range of 0.1-15 wt. %.

3. Gasoline according to claim 2 and wherein the amount of said phenol is in the range of 0.1-10 wt. % and the total of said amounts is in the range of 1-15 wt. %.

4. Gasoline according to claim 1 and wherein said ether is methyl methoxypropane.

5. Gasoline according to claim 1 and wherein said phenol is selected from the group consisting of ortho, meta and paracresol and mixtures of two or more said cresols.

6. Gasoline according to claim 5 and wherein said ether is methyl methoxypropane.

7. Gasoline according to claim 6 and wherein said phenol consists essentially of paracresol.

8. Gasoline according to claim 6 and wherein said amount of said phenol is in the range of 0.5-15%, said amount of said ether is in the range of 0.5-15% and the total of said amounts is in the range of 1-16%.

9. Gasoline according to claim 8 and wherein the total of said amounts is in the range of 2-10%.

10. Gasoline according to claim 1 wherein said ether is selected from the group consisting of diisopropyl ether, diisobutyl ether, methyl isopentyl ether, methyl isopropyl ether, and mixtures of two or more said ethers.

11. The composition of claim 1 wherein said base stock contains in the range of 40-75% paraffins, 0-10% naphthenes, 0-20% olefins, and 20-40% aromatics.

12. The composition of claim 1 wherein said base stock has an RON in the range of 80-100 and an MON in the range of 75-95.

13. The composition of claim 12 wherein said base stock contains in the range of 50-60% paraffins, 1-10% naphthenes, 2-10% olefins and 28-38% aromatics.