CN109312244B

CN109312244B - Fuel antiknock agent, process for producing the same, and fuel composition

Info

Publication number: CN109312244B
Application number: CN201680085361.8A
Authority: CN
Inventors: 熊靓; 严斌; 叶世春
Original assignee: Guangchangda New Material Technology Service Shenzhen Co ltd; Shenzhen Guangchangda Petroleum Additive Co ltd
Current assignee: Guangchangda New Material Technology Service Shenzhen Co ltd; Shenzhen Guangchangda Petroleum Additive Co ltd
Priority date: 2016-05-20
Filing date: 2016-05-20
Publication date: 2021-02-19
Anticipated expiration: 2036-05-20
Also published as: WO2017197640A1; CN109312244A

Abstract

A fuel antiknock agent, a method for manufacturing the same, and a fuel composition containing the same, wherein the fuel antiknock agent includes: (i) one or more compounds of the general formula I, in which R₁Selected from H or C1-6 alkyl, R₂Selected from C1-8 alkyl; and (ii) one or more compounds of the formula II, in which R₃Selected from C2-6 alkenyl, R₄Selected from H or C1-4 alkyl, or R₃And R₄Together with the carbon atom to which they are attached form a C5-10 saturated or unsaturated five-, six-, seven-or eight-membered ring, R₅Selected from H or C1-8 alkyl. During the preparation, the components are mixed and stirred for 0.5 to 3 hours at the temperature of 50 to 100 ℃.

Description

Fuel antiknock agent, process for producing the same, and fuel composition

Technical Field

The invention relates to a fuel antiknock agent and a fuel composition, and belongs to the field of petrochemical industry.

Background

It is well known that the most effective way to increase the efficiency of a gasoline engine is to increase the compression ratio of the engine, but as soon as the compression ratio is increased, the detonation combustion is significantly enhanced, requiring a higher octane gasoline to reduce the detonation. The method for improving the octane number of the gasoline mainly comprises catalytic reforming and aromatization technologies, processes such as etherification, alkylation, isomerization and the like, or blending the gasoline, and can be realized by adding a gasoline octane number improver (commonly called antiknock). The former relates to the improvement of refining process, and has the problems of complex process and huge investment, while the latter is effective and economical, so that the gasoline antiknock agent is favored by the majority of oil refining manufacturers.

Gasoline antiknock agent is divided into two types of metal ash and organic ash-free. Primarily metals used initially were ashy antiknock agents such as tetraethyllead, Methylcyclopentadienyl Manganese Tricarboxy (MMT), ferrocene, and the like. Although the antiknock can effectively improve the antiknock performance of gasoline, the antiknock has been gradually replaced and stopped in developed countries such as Europe and America due to the problems of toxicity, exhaust particulate matter emission, harm to engine cylinders and exhaust systems and the like, and the research on the antiknock is in a relative lag phase.

In recent years, research on anti-knock agents in various countries has focused on organic ashless anti-knock agents, which mainly include ethers, alcohols, esters, and the like. People blend gasoline by methyl tert-butyl ether (MTBE) firstly, but the MTBE is added in a large amount (10-15%), the cost is high, the economical efficiency is poor, and then underground water pollution is caused by the MTBE, so that some areas in the United states are forbidden to add the MTBE into the gasoline for use. In addition, alcohols, esters, aromatic hydrocarbons and the like can also be used for improving the octane number of the gasoline, but the defects of poor effect, high toxicity, high cost and the like generally exist. Therefore, the development of an efficient and cheap organic ashless gasoline antiknock agent is an urgent need to be solved in the petroleum refining industry at home and abroad at present.

Russian patent RU2011139487 mentions that N-methyl-p-anisidine can be used as an anti-knock additive or an engine fuel additive, and has a certain octane number improvement effect, but the synthetic process is complex, the production cost is high, the addition amount of the N-methyl-p-anisidine in gasoline is large, the content of gasoline nitrogen exceeds the standard, and the wide application of the N-methyl-p-anisidine is limited.

U.S. Pat. No. 4,982,071 mentions that (N-methyl) p-anisidine and dicyclopentadiene DCPD have a certain synergistic effect, and the addition amount of (N-methyl) p-anisidine in gasoline can be greatly reduced. However, since dicyclopentadiene is a kind of diolefin, there is a certain limitation added to gasoline in some countries (including china).

Accordingly, there remains a need in the art to find a fuel antiknock formulation that is superior to existing antiknock formulations.

Disclosure of Invention

The invention aims to provide a fuel antiknock agent and a fuel composition containing the fuel antiknock agent.

One aspect of the present invention provides a fuel antiknock agent comprising:

(i) one or more compounds of formula I

Wherein R1 is selected from H or C1-6 alkyl, R2 is selected from C1-8 alkyl; and

(ii) one or more compounds of formula II

Wherein R3 is selected from C2-6 alkenyl, R4 is selected from H or C1-4 alkyl, or R3 and R4 together with the carbon atoms to which they are attached form a C5-10 saturated or unsaturated five-, six-, seven-or eight-membered ring, R5 is selected from H or C1-8 alkyl.

In one aspect of the invention, R1 is selected from H or C1-4 alkyl, such as methyl, ethyl, isopropyl or isobutyl, and the like.

In one aspect of the invention, R2 is selected from C1-8 alkyl, such as methyl, ethyl, isopropyl, isobutyl, neopentyl or n-octyl, and the like. In one aspect of the invention, R2 is selected from C1-4 alkyl.

In one aspect of the invention, the-OR 2 group is para to the-NHR 1 group.

In one aspect of the invention, R3 is selected from C2-6 alkenyl groups such as vinyl, allyl or 3-methyl-1-butenyl groups and the like. In one aspect of the invention, R3 is selected from C2-4 alkenyl.

In one aspect of the invention, R4 is selected from H or C1-4 alkyl, such as methyl, ethyl, isopropyl or isobutyl, and the like.

In one aspect of the invention, R3 and R4 together with the carbon atoms to which they are attached form a C5-10 saturated or unsaturated five-, six-, seven-, or eight-membered ring, such as cyclopentane, cyclopentene, cyclohexene, or methylcyclooctene, and the like. In one aspect of the invention, R3 and R4 together with the carbon atoms to which they are attached form a C5-10 unsaturated five-, six-, seven-, or eight-membered ring with one double bond, such as cyclohexene. For example, where R5 is H, R3 and R4 together with the carbon atoms to which they are attached form cyclopentene, the compound of formula II is indene.

In one aspect of the invention, R5 is selected from H or C1-8 alkyl, such as methyl, ethyl, isopropyl, isobutyl, neopentyl or n-octyl, and the like. In one aspect of the invention, R5 is selected from C1-4 alkyl.

The term "Ca-b alkyl" as used herein refers to an alkyl group having a total of a to b carbon atoms, which may be a straight chain alkyl group or a branched chain alkyl group; either unsubstituted or further substituted, where appropriate, with conventional substituents, is contemplated.

The term "Ca-b alkenyl" as used herein refers to an alkenyl group having a total of a to b carbon atoms, which may be a straight chain alkenyl group or a branched alkenyl group; either unsubstituted or further substituted, where appropriate, with conventional substituents, is contemplated.

The "Ca-b n membered ring" of the present invention means an n-membered ring having a total of specifically a to b carbon atoms, which may be ring-forming atoms or substituents on the ring-forming atoms; the n-membered ring may be either unsubstituted or, where appropriate, further substituted with conventional substituents.

The common substituent in the invention can be C1-4 alkyl, amino, alkoxy, hydroxyl and the like.

In one aspect of the invention, R1 is H OR methyl, R2 is methyl OR ethyl OR isopropyl, the-OR 2 group is para to the-NHR 1 group, whereby the compound of formula I is p-anisidine, p-phenetidine, p-anisidine isopropyl ether, N-methyl-p-anisidine, N-methyl-p-phenetidine OR N-methyl-p-anisidine isopropyl.

In one aspect of the present invention, component (i) consists of p-anisidine and N-methyl-p-anisidine, or consists of p-anisidine and N-methyl-p-phenetidine, or consists of p-phenetidine and N-methyl-p-anisidine, or consists of p-phenetidine and N-methyl-p-phenetidine.

In one aspect of the invention, R4 and R5 are H and R4 is vinyl, whereby the compound of formula II is styrene. In one aspect of the invention, the compound of formula II is a homologue of styrene. Homologues as referred to herein refer to compounds which differ by one or more, such as 2 to 4, methylene groups.

In one aspect of the invention, R4 and R5 are methyl groups and R4 is vinyl, whereby the compound of formula II is

(2, 5-Dimethylstyrene).

In one aspect of the invention, R5 is H, R3 and R4 together with the carbon atoms to which they are attached form cyclopentene or cyclopentane, whereby the compound of formula II is indene or indane. In one aspect of the invention, the compound of formula II is an indene or an indane homologue.

In one aspect of the invention, R5 is H, R3 and R4 together with the carbon atom to which they are attached form cyclohexene, whereby the compound of formula II may be

(1, 2-dihydronaphthalene). In the case where R3 and R4 together with the carbon atom to which they are attached form cycloheptene, the compound of formula II may be

(6, 7-dihydro-benzo [7 ]]Rotalene).

In one aspect of the invention, component (ii) consists of styrene, or consists of styrene and indene or indan, or consists of styrene, indene and indan.

In one aspect of the invention, component (i) comprises 10 to 80%, such as 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80% by total weight of the fuel antiknock agent, or any range, such as 10 to 30%, inclusive, of two specific amounts thereof.

In one aspect of the invention, component (ii) comprises 20 to 90%, such as 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% by total weight of the fuel antiknock agent, or any range, such as 70 to 90%, inclusive, of two specific amounts thereof.

In one aspect of the invention, the fuel antiknock agent consists of component (i) and component (ii).

In one aspect of the invention, the fuel antiknock agent is an organic ashless gasoline antiknock agent which can significantly improve the octane number of gasoline and enhance the antiknock performance of gasoline.

In one aspect of the invention, component (i) in the fuel antiknock is as low as 20% or less.

In one aspect of the invention, the fuel antiknock further comprises (iii) one or more adjuvants and/or (iv) one or more organic solvents, each of which may be present in an amount of 0 to 50%, such as 5%, 10%, 20%, 30%, 40% or 50%, or any range where two of the specified amounts are endpoints, such as 5 to 20%, based on the total weight of the fuel antiknock.

The adjuvant may be selected from: antioxidants (e.g., 2, 6-di-t-butyl-4-methylphenol, BHT, p-ethylphenol, and p-t-butylphenol), anti-discoloration agents (e.g., benzotriazole, N-diethylhydroxylamine), detergents (e.g., polyetheramine, polyisobutylene amine), corrosion inhibitors (e.g., imidazoline, fatty amine), antifoaming agents (e.g., dimethylsilicone oil), furfuryl alcohol, tetrahydrofurfuryl alcohol, t-butyl alcohol, anisole, methyl t-butyl ether (MTBE), and the like.

The organic solvent may be selected from: hydrocarbons such as xylene, trimethylbenzene, heavy aromatics, gasoline, kerosene, naphtha; alcohols such as ethanol, isopropanol; ethers such as tetrahydrofuran, dioxane, etc.

In one aspect of the invention, the fuel antiknock agent is composed of component (i), component (ii), and component (iii). In one aspect of the invention, said component (iii) is selected from furfuryl alcohol and tetrahydrofurfuryl alcohol.

One aspect of the present invention provides a method of making the fuel antiknock of the present invention, the method comprising stirring the components at a temperature above room temperature until thoroughly mixed. The temperature is for example 50-100 deg.c, or for example 60-70 deg.c. The stirring time is, for example, 0.5 to 3 hours or 0.5 to 2 hours, for example, about 1 hour.

One aspect of the present invention provides a fuel composition comprising:

(a) a major amount of a hydrocarbon mixture in the gasoline boiling range; and

(b) a small amount of the fuel antiknock agent of the present invention.

In one aspect of the invention, the fuel composition consists of component (a) and component (b).

In one aspect of the present invention, the component (a) may be straight run gasoline, FCC gasoline, alkylated gasoline, hydrogenated gasoline or blend gasoline thereof, fischer-tropsch synthesized gasoline or coal-based gasoline, or the like.

In one aspect of the invention, the component (a) is a low grade gasoline, such as 90#, 92# or 93# gasoline.

In one aspect of the invention, the component (b) may comprise 0.01 to 10.0%, such as 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.5%, 2.0%, 3.5%, 5.0%, 7.5%, 10.0%, etc., of the total volume of the fuel composition, or any range wherein two specific contents are endpoints, such as 0.5 to 1.0%.

The antiknock agent can be used independently or compounded with other various gasoline additives, and can be added by manufacturers or consumers in the links of refineries, terminals, retailers and the like.

The inventor unexpectedly finds that the amino phenylalkyl ether (i) and the aromatic hydrocarbon derivative (ii) have synergistic effect, and the octane number of the gasoline can be synergistically improved. The antiknock test result of the antiknock agent obtained by compounding the components shows that the octane number of the gasoline can be obviously improved by adding a small amount of the antiknock agent into the gasoline, and the knocking generated by the combustion of the gasoline in an engine is reduced.

Compared with the prior art, the invention has the beneficial effects that:

1) the gasoline octane number can be effectively improved, the sensitivity to low-octane gasoline is good, the effect on medium-high octane gasoline is obvious, and economic feasibility is provided for large-scale application of the gasoline in oil products;

2) the product has stable property and good thermal stability, and can be well compatible with oil products;

3) the product of the invention can greatly reduce the formation of gasoline colloid and effectively improve the quality of gasoline; compared with the traditional aniline antiknock agent, the nitrogen content is greatly reduced, and the exhaust emission can be effectively improved; the octane number of the gasoline can be effectively improved, the content of aromatic hydrocarbon blending components of the gasoline is reduced, and the emission of automobile particulate matters is reduced;

4) the product of the invention has good combustibility, does not produce sediment or residue, has little damage to an engine and does not damage a three-way catalyst;

5) the product of the invention does not contain heavy metal, is nontoxic and does not cause pollution to the environment.

Drawings

FIG. 1 is a graph of RON of gasoline versus the amount of antiknock additive added;

FIG. 2 is a graph of RON versus antiknock ratio for gasoline;

FIG. 3 is a graph of RON versus antiknock ratio for gasoline.

Detailed Description

The invention is further illustrated by the following specific examples, which are not to be construed as limiting the invention to the particular details set forth in the examples.

Example 1: preparation of antiknock agent

100kg of para-anisidine and 400kg of styrene are added into a reaction kettle with a mechanical stirrer, a thermometer, a feeding funnel and a condenser tube, the temperature is raised to 60 ℃, the mixture is stirred for 1 hour, and the mixture is cooled to room temperature to obtain the gasoline antiknock agent.

99.5ml of No. 92 base gasoline was added with 0.5ml of the above antiknock agent and tested in accordance with GB/T5487 gasoline octane number determination (research method) to determine an increase in the RON octane number of gasoline from 92.5 to 93.5.

Examples 2 to 6: preparation of antiknock agent

The components, contents, addition amounts, stirring temperatures and stirring times of the antiknock agents of examples 2 to 6 were adjusted by using the equipment and procedure of example 1.

The above parameters and RON values are summarized in Table 1 below.

Table 1: preparation parameters and RON improvement results for the antiknock agents of examples 1-6

Note: the RON of the blank gasolines of examples 1-6 above were all 92.5.

The synergy of (N-methyl) p-aminobenzene/ethyl ether with styrene/indene is evident from the data of examples 1-6 in combination with other experiments performed by the inventors. If the RON of the gasoline needs to be improved by about 1 point, 0.5 v% of para-anisidine compound antiknock agent is added properly; if the improvement is about 3 points, 1 v% of N-methyl paraaminobenzene (or ethyl) ether compound antiknock agent is added properly.

Comparative examples 1 to 3

The antiknock agents of comparative examples 1 to 3 were prepared by using the equipment and procedure of example 1 while changing the components, contents, addition amounts, stirring temperature and stirring time of the antiknock agent.

The above parameters and RON values are summarized in Table 2 below, and the data of examples 1 and 2 are summarized in Table 2 for comparison.

Table 2: comparative examples 1-3 preparation parameters of antiknock and RON of gasoline after antiknock addition

Note: the RON of the blank gasolines of comparative examples 1-3 above were all 92.5.

It can be seen from the data of comparative examples 1 to 3 that the synergy between the (N-methyl) p-anisidine and the components referred to in comparative examples 1 to 3 is small or non-existent.

Example 7: effect of different amounts of antiknock additive on RON

The antiknock agent obtained in example 1 was added to base gasoline # 92 in percentages by volume of 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.5%, and the octane number of the gasoline was varied as shown in table 3 below.

Table 3: effect of different amounts of antiknock additive on RON

The addition amount of the antiknock agent is v%	0 (blank)	0.2	0.4	0.6	0.8	1.0	1.5
								RON	92.5	92.9	93.6	93.9	94.0	94.0	94.1

FIG. 1 shows the data listed in Table 3, and it can be seen that the RON is significantly improved when the amount of the para-anisidine compound antiknock agent is in the range of 0.2-0.6 v%.

Example 8: effect of different antiknock component ratios on RON

The antiknock agent obtained by compounding p-anisidine and styrene according to different proportions is added into No. 92 base gasoline by 0.5 v%, and the octane number change of the gasoline is shown in the following table 4.

Table 4: effect of different antiknock ratios on RON

Content of p-anisidine, wt.%	Blank space		10％	20％	30％	40％	50％
								RON	92.5	92.9	93.7	93.7	93.7	94.1

FIG. 2 shows the data listed in Table 4, and it can be seen that the synergistic effect with styrene is more significant when the content of para-anisidine in the antiknock agent is lower. Considering that the price of the para-anisidine is far higher than that of the styrene, the anti-knock agent has the highest cost performance when the content of the para-anisidine is 20 wt%. Of course, the content of para-anisidine can be increased to obtain better effect without considering the cost or reducing or inverting the cost difference for some reason.

Example 9: effect of different antiknock component ratios on RON

The antiknock agent obtained by compounding N-methyl para-anisidine and styrene according to different proportions is added into No. 92 base gasoline by 1.0 v%, and the octane number change of the gasoline is shown in the following table 5.

Table 5: effect of different antiknock ratios on RON

Content of N-methyl-p-anisidine,% by weight	Blank space		20％	30％	40％	50％	60％
								RON	92.5	94.0	94.6	95.1	95.5	95.7

FIG. 3 shows the data listed in Table 5, and it can be seen that the synergistic effect is not as significant as in the case of p-anisidine when the content of N-methyl-p-anisidine in the antiknock agent is low, but RON continues to increase as the content thereof increases, making up for the disadvantage of p-anisidine.

Based on the results shown in FIGS. 2 and 3, in one embodiment of the present invention, component (i) is composed of p-anisidine and N-methyl-p-anisidine, wherein the content of p-anisidine is within 20% (by total weight of the antiknock agent), but the content of the entire component (i) exceeds 20%, for example, 30% to 60% (by total weight of the antiknock agent). Of course, (N-methyl) p-anisidine may be each independently replaced with (N-methyl) p-phenetidine.

Comparative example 4

Pure (N-methyl) p-aminobenzene/diethyl ether was added to # 92 base gasoline at 0.5 v% each, and the octane number of the gasoline was only increased by about 0.5 in all four cases. In fact, the inventors found through experiments that the octane number increase corresponding to the addition of 0.1 v% of (N-methyl) p-aminobenzene/diethyl ether was about 0.1, while the increase in the aromatic hydrocarbon derivative formulated therewith was reported to be comparable to this level, and therefore the octane number increase of gasoline should be 0.5 for the (N-methyl) p-aminobenzene/diethyl ether-aromatic hydrocarbon derivative formulated antiknock additive, if predicted by linear addition without taking into account the synergistic effect, and was much lower than the actual values of examples 8 and 9. The synergistic effect of the compounded antiknock agent of the invention is proved.

Example 10: influence of addition of antiknock agent on physicochemical properties of gasoline

The antiknock agent obtained in example 2 was added to base gasoline No. 92 in a volume percentage of 1.0%, and Table 6 shows the changes in the physical and chemical properties of the gasoline before and after the antiknock agent was added.

As can be seen from Table 6, before and after the antiknock agent is added, indexes such as colloid, sulfur, manganese, iron, mechanical impurities, moisture and the like in the gasoline are not obviously increased, and the antiknock agent has little influence on indexes such as density, steam pressure, induction period and the like, and can completely meet the general requirements of gasoline additives.

Example 11: effect of antiknock additive on automotive hardware

The antiknock agent obtained in example 2 was added to base gasoline No. 92 in a volume percentage of 1.0%, and a road driving test was carried out using the obtained gasoline composition, and the pollutant emissions by the working condition method and the fuel economy were tested in accordance with the chinese standard GB18352.3-2005, "limit of light vehicle pollutant emissions and measurement method (chinese stages III and IV)", and the test results are shown in table 7.

Table 7: test result of pollutant emission and fuel economy of Chevrolet SGM7166MTC car by working condition method

Item	HC(g/km)	CO(g/km)	NOx(g/km)	Oil consumption (L/100km)
					Original vehicle	0.05	0.81	0.01	9.41
After using the antiknock agent	0.03	0.47	0.02	9.32

The data in the table 7 show that the antiknock agent has certain functions of saving oil and reducing emission. In addition, the vehicle is normally used, and the problems of abnormality of an engine, corrosion and abrasion of parts, damage of an oil pump and the like are not found.

Example 12: effect of antiknock agent on RON of high and low grade base gasolineSound box

1.0 v% of antiknock agent (50 wt% of N-methyl-p-phenetidine +50 wt% of styrene) is added into 93# base gasoline, and the octane number is increased from 93.4 to 96.3; the octane number increased from 98.1 to 99.7 for the 97# base gasoline under the same experimental conditions. Therefore, the antiknock agent has more remarkable effect when being added into low-grade gasoline.

Example 13: the antiknock of the invention is compounded with the existing antiknock

After 10% of MTBE (accounting for the total volume of the gasoline composition) is added into base gasoline with the RON octane number of 93.3, the octane number is improved to 95.8; the amount of MTBE added was reduced to 5 v%, and compounded with the antiknock of example 1 and then added to gasoline so that the amount of the latter added was 0.2 v%, thereby obtaining an octane number of 95.7, as shown in table 8 below.

Table 8:

this example shows that the main agent of the antiknock agent of the present invention also has a synergistic effect with the conventional antiknock agents such as MTBE which are generally used in the market. MTBE has certain toxicity, the requirements of the current national standard are stricter and stricter, the upper limit of the addition of MTBE in gasoline is continuously reduced, and the actual dosage of MTBE can be greatly reduced on the premise of reaching the level of comparable effect by adding the antiknock agent (compounded) disclosed by the invention into the existing MTBE antiknock agent. The method not only reduces the cost, but also has the advantage of environmental protection and has great economic and social benefits.

It should be noted that base gasoline has a certain difference in octane number measured by the same method due to differences in production area, components, and the like, but the present invention is not affected by the octane number of the base gasoline. The advantages of the present invention are manifested by octane number increments (delta octane numbers) before and after the addition of the antiknock agent. Embodiments of the present invention can also be illustrated by delta octane to exclude differences in octane number for different batches and different sources of base gasoline.

The present invention is further illustrated by the following specific examples, but is not limited to the details disclosed in the foregoing examples. Various equivalents and obvious modifications may be made by those skilled in the art based on the disclosure herein, and it is intended that the present invention cover such alternatives and modifications.

Claims

1. A fuel antiknock agent, comprising:

component (I) one or more compounds of the general formula I

Wherein R is₁Selected from H or C1-6 alkyl, R₂Selected from C1-8 alkyl; and

component (II) one or more compounds of the formula II

Wherein R is₃Selected from C2-6 alkenyl, R₄Selected from H or C1-4 alkyl, or R₃And R₄Together with the carbon atom to which they are attached form a C5-10 saturated or unsaturated five-, six-, seven-or eight-membered ring, R₅Selected from H or C1-8 alkyl.

2. The fuel antiknock agent of claim 1, wherein R₁Is H or methyl, R₂Is methyl, ethyl or isopropyl; -OR₂The group being located at-NHR₁Para to the group.

3. A fuel antiknock agent according to claim 1, wherein component (ii) is one or more compounds selected from styrene, indene or indane.

4. A fuel antiknock agent according to any preceding claim, wherein component (i) comprises from 10 to 80% by weight of the total fuel antiknock agent and component (ii) comprises from 20 to 90% by weight of the total fuel antiknock agent.

5. A fuel antiknock according to any of claims 1 to 3, which includes from 0 to 50% by weight of the total fuel antiknock, of one or more adjuvants selected from: antioxidant, anti-discoloration agent, detergent, corrosion inhibitor, defoaming agent, furfuryl alcohol, tetrahydrofurfuryl alcohol, tert-butyl alcohol, anisole and methyl tert-butyl ether.

6. A fuel antiknock agent according to any of claims 1 to 3, which includes from 0 to 50% by weight of the total fuel antiknock agent of one or more organic solvents selected from: one of xylene, trimethylbenzene, heavy aromatics, gasoline, kerosene, naphtha, ethanol, isopropanol, tetrahydrofuran, and dioxane.

7. A method of making a fuel antiknock according to any preceding claim, which method comprises mixing and stirring the components at a temperature of from 50 to 100 ℃ for from 0.5 to 3 hours.

8. A fuel composition comprising:

component (a) a hydrocarbon mixture in the gasoline boiling range; and

a fuel antiknock agent as claimed in any one of claims 1 to 6, component (b) being present in an amount of from 0.01 to 10.0% by volume based on the total fuel composition.

9. The fuel composition of claim 8, wherein component (b) comprises from 0.01 to 5.0% by volume of the total fuel composition.

10. The fuel composition of claim 8, wherein said component (a) is straight run gasoline, FCC gasoline, alkylated gasoline, hydrogenated gasoline or blended gasoline of said straight run gasoline, said FCC gasoline, said alkylated gasoline and said hydrogenated gasoline, fischer-tropsch synthesis gasoline or coal gasoline.