CZ280251B6 - Derivatives of dicarboxylic acids as additives in low-lead or lead-free petrols - Google Patents

Abstract

Derivatives of dicarboxylic acids as additives to low-lead or unleaded automotive gasoline, which prevent the wear of exhaust valve seats in cars not structurally adapted for the combustion of unleaded gasoline. The dicarboxylic acid derivatives of the invention have the structural chemical formula (I)

Description

Dicarboxylic Acid Derivatives as Additives for Low-Leaded or Unleaded Motor Gasoline ·

Technical field

The present invention relates to dicarboxylic acid derivatives as additives to low-lead or unleaded motor gasolines which prevent the wear of exhaust valve seats in vehicles not designed to burn unleaded gasoline.

BACKGROUND OF THE INVENTION

The trend towards the use of unleaded gasoline is noticeable worldwide as a result of efforts towards a healthier environment. The US began production of unleaded gasoline in the early 1970s. In Japan, unleaded gasoline began to be produced in 1974 and in Europe in early 1984. Since then, its share in the production and consumption of gasoline has been increasing rapidly. The global trend thus clearly leads to the production and use of only unleaded gasoline. For example, since March 1986, only unleaded petrol has been used exclusively in Japan [1,2]. In the USA, they accounted for 90% of total production in 1990, and the early 1990s are considered to exclude the production of leaded gasoline completely.

In Europe, the situation is not as clear-cut as overseas, given the time lag and the diversity of the car fleet and the refinery's technical capabilities. Unleaded petrol searches its market position in each country differently quickly. In developed European countries, unleaded gasoline production currently accounts for around 50% of total gasoline production. Total unleaded petrol production is estimated to be at least 75% in 1995 [3,4], compared to 21,3% in 1986 and 26% in 1987 [5,6]. Unleaded petrol has been produced and sold in Czechoslovakia since 1986. In 1990, its production did not exceed 3% of total petrol production.

The production and distribution of unleaded gasoline from the outset encounters a major problem which, together with the technical capabilities of refineries, is a major brake on the immediate transition to the production and use of only unleaded fuel. This problem is the impossibility of burning unleaded gasoline in cars constructed on leaded fuel. The combustion of unleaded petrol in such cars results in damage to the cylinder head of the engine to the engine itself and to the decommissioning of the car [7-12]. This is basically an old-fashioned problem with which car manufacturers encountered in the early 1920s, which suddenly solved itself, with the addition of lead-based anti-knockers to gasoline. The number of cars at risk of burning unleaded gasoline has been estimated to be 70 million worldwide by 1987 [10], of which around 7 million in the UK [13].

In the CSFR, the number of cars unable to use unleaded fuel is estimated to be around 70% of the total number of passenger cars and, due to the statistically determined 5% replacement of passenger cars in the CSFR per year, their complete disappearance is expected only around 2010 [7,8].

-1GB 280251 B6

Almost all cars manufactured by 1971 belong to this group of cars [10]. On the other hand, most automobile manufacturers have been producing models capable of burning unleaded gasoline since 1986, mainly since 1986 [14,15].

The cause of engine failures in the combustion of unleaded fuel in these cars is the quality of the material from which the seats of the exhaust valves are made. the entire engine cylinder head. If these are made of cast iron or other similar soft material, they burn rapidly and wear when unleaded gasoline is burned. As a result, the exhaust valves become more and more recessed into the cylinder head of the engine, and the valve clearance is thereby constantly reduced. The final stage of this process is the imperfect closing of the combustion chamber, the loss of compression and engine power, the burning of the exhaust valves and their seats. Finally, the engine cylinder head is destroyed [10,12].

The degree and speed of the exhaust valve recess is dependent on the design and operating parameters of the car. In addition to the hardness of the seat material, the design parameters include valve rotation, spring tension, seat angle and width, operating temperatures and valve geometry. The most important of the operating parameters are the engine speed, its load and the richness of the fuel-air mixture. Valve rotation, high speed and engine load, and lean mixtures have a drastic effect on the depression of the exhaust valve seats [10,12].

Practically only in the twilight of the use of lead compounds in gasoline, it turned out that, in addition to increasing the detonation stability, lead in gasoline fulfilled another very important function of protecting the exhaust valve seats from mechanical wear during engine operation. It is assumed that the lead combustion products of lead anti-knockers form a thin protective film on the valve seat surfaces, preventing high-temperature oxidation and abrasion, and reducing adhesion and material transfer, thus protecting them from unwanted wear [10].

The solution to the problem that would lead to the use of unleaded fuel in this endangered group of cars is:

and / replacing the cylinder heads of these cars with heads with specially cured exhaust valve seats; which is virtually impossible and financially unacceptable to many run-off types, b / adding to lead-free petrol such a harmless additive to catalytic converters that would replace the film-forming function of lead compounds and provide the exhaust valve seats with the necessary protection. Only two kinds of ingredients of this designation are currently offered on the world market. Although functionally satisfactorily satisfactory for several foreign engines, ŠKODA engines failed to provide effective protection against the bore of their exhaust seats, even at several times higher dozing than recommended by the manufacturer [8].

Another option is the use of leaded petrol until such vehicles are represented in the fleet, but under the 2CZ 280251 B6 it is not possible to produce and use only unleaded petrol with a negative environmental impact.

SUMMARY OF THE INVENTION

The most preferred solution to this is the use of only unleaded gasoline containing dicarboxylic acid derivatives of the present invention. Their addition ensures that the combustion of completely unleaded or low-leaded petrol gasoline does not damage the exhaust valve seats made of non-hardened materials of different types, such as cast iron. The dicarboxylic acid derivative additives described in this invention are harmless to health and harmless to catalytic exhaust gas converters.

The dicarboxylic acid derivatives according to the invention have the structural chemical formula I:

COOX / ^R 1 (R ₂ ) and \ / CO-Y \ (R ₃ > b (AND) in which it means

a divalent hydrocarbon function having a total carbon number of from 5 to 38, or a hydrocarbon function having a nitrogen atom in the amino group and / or an oxygen atom in a hydroxy and / or ether group having a total number of carbon atoms of 1 to 38;

R ₂ is a monovalent hydrocarbon functional group having a carbon number from 1 to 42 or hydrogen,

X hydrogen and / or an alkali metal and / or alkaline earth metal group,

Y oxygen or nitrogen, a and b integers zero or 1, with a + b> 1,

R _{3 is} hydrogen, or a monovalent hydroxy-substituted hydrocarbon function of from 1 to 42, or a monovalent hydrocarbon function of from 1 to 42, or a monovalent function of structural formulas II or III or IV,

- [- (CH ₂ ) _c -NH-] _d -R ₄ (II)

- (- CH ₂ -CH-O-) _e -R ₂ (III)

-3GB 280251 B6

- (- CH-CH ₂ -O-) _{e - 1} -CH-CH ₂ - [- NH- (CH ₂ ) _c -] _d -NR ₂ (IV) ^R 5 ^R 5 ^R 6 wherein:

R ( _{4) is} hydrogen or a monovalent hydrocarbon functional group having a carbon number of 1 to 42 or a functional group having structural chemical formula III,

R _{5 is} hydrogen or a monovalent hydrocarbon function having a carbon number of 1 to 3,

R _{6 is} hydrogen or - (- CH-CH ₂ -O-) _f -H,

C whole number from 1 to 10, d whole number from zero to 6, E whole number from 1 to 50, F whole number from 1 to 50.

Such dicarboxylic acid derivatives, applied in unleaded automotive gasoline, are effective inhibitors of the exhaust valve seat wear of cars not designed to burn unleaded gasoline and thus allow their continuous, trouble-free operation on this fuel.

In order to improve handling, in particular viscosity and thus pumpability at the stage of packaging, transport and application, the dicarboxylic acid derivatives as an additive to the gasoline according to the invention may also contain an auxiliary component, which is an organic solvent, of the preferred aromatic type. Suitable solvent types are toluene, xylene, aromatic hydrocarbons having from 9 to 13 carbon atoms in the molecule, or technical mixtures thereof, such as the naphtha reformate, the reformate fraction boiling in the range of 75 ° C to 250 ^e C, the fraction from pyrobenzine with a similar distillation range. The aromatic hydrocarbon content of these mixtures is usually above 25% by weight.

In order to ensure the above-mentioned effects of the dicarboxylic acid additives according to the invention, these are added to the gasoline at a concentration of from 0.025 to 1.1% by weight. If the additive according to the invention also contains an auxiliary component which is an organic solvent specified above, then the resulting addition of the additive to the gasoline is chosen such that the concentration of the effect of the component is within the stated range.

In order to improve pumpability and also to maintain the required content in automotive gasoline, the additive according to the invention may be further diluted either directly with gasoline, one of its components or other hydrocarbon solvent before it is added to the gasoline.

-4GB 280251 B6 can be added: it can be added to the gasoline of either automotive gasoline in a refinery at the ready stage of consumption or distribution, for example at the preparation stage

The additive according to the invention directly in (primary additive) or gasoline at service stations (secondary additive). The secondary addition of the additive according to the invention is advantageous especially in those cases where the gasoline is produced without its content.

DETAILED DESCRIPTION OF THE INVENTION

The following are documented examples! the advantages and practical use of the specified dicarboxylic acids as additives to the gasoline according to the invention, but without the scope of the invention being thereby limited in any way.

Example 1

A four-cylinder petrol engine with a cylinder capacity of 1174 cm ³ with a cast-iron cylinder head was subjected to a site engine test under the conditions of Table 1, using total unleaded petrol (0.0000 g Pb / l) with an octane rating of 96 and 87 as well as unleaded petrol containing a lead concentration for unleaded petrol, ie 0.013 g Pb / l with the same octane level. During the test, the valves were measured every 6 hours and adjusted, if necessary, so that their minimum value was not less than 0.2 mm. After the 36-hour engine test, the engine cylinder head was removed to remove the intake and exhaust valves. After detecting the change in valve weights, the total depression of the exhaust valve seats was measured. The results obtained are shown in Tables 2 and 3, in which the individual values represent both the size of the average recess of 4 rolls and the values for one of the most recessed rolls. The results of the test showed that the use of unleaded gasoline in engines of this type is not possible.

A similar test was also performed with said total unleaded autobenzine (0.0000 g Pb / l), but containing 850 ppm of a dicarboxylic acid derivative according to the invention with a chemical structural formula (I> where ^R 1 ' ^x 3 ^e Ca ²⁺ / ² , Y is nitrogen, ^R ₂ is hydrogen, a = 1, b = 1, R ₃ is - [- (CH ₂ ) _c -NH-] _d -R ₄ , wherein c = 2, d = 2 and R ₄ is polypropenyl with an average molecular weight of 450 g / mol.

The dicarboxylic acid derivative was prepared by reacting phthalic anhydride with N-polypropenyl-diethylenetriamine and then neutralizing the resulting phthalic acid derivative with calcium oxide.

-5GB 280251 B6

The results of this test showed that no exhaust valve seats were clogged on any engine cylinder, even if the test duration was extended to 56 hours (the average change in the valve clearance of the exhaust valves was -0.0075 mm, the maximum measured value was -0.04 mm).

Example 2

The four-cylinder spark ignition engine type Š 742.13 with a cast-iron cylinder head was subjected to a long-term engine service life test (300 hours) under conditions according to CSN 30 0506, using unleaded petrol with octane rating 96 / 1). The fuel used was saturated with 700 ppm of an additive according to the invention with structural chemical formula (I) wherein

R f is -CH ₂ -CH-, X is sodium, Y is oxygen, and is zero, ^R 12 ^h 23b = 1, R ₃ is - (- CH-CH ₂ -O-) _{e - 1} -CH-CH ₂ -NC ₁₄ H ₂₉ , wherein e = 3-5 CH ₃ CH ₃ R ₆ and R 8 is - (- CH ₂ -CH-O-) f H wherein f = 1-3.

ch ₃

The dicarboxylic acid derivative was prepared by reacting tetrapropenylsuccinic anhydride with propoxylated tetradecylamine and subsequent neutralization of the resulting intermediate with sodium hydroxide.

The additive of this composition was dissolved in the naphtha reformate prior to addition to unleaded autobenzine so that the resulting solution contained 50% active ingredient.

The results of this test showed that none of the engine cylinders had exhausted the exhaust valve seats, (the average change in the exhaust valve valve clearance was 0.055 mm). Unleaded gasoline containing the aforementioned additive according to the invention fully protected the exhaust valve seats of the used engine while not deteriorating any of its operating parameters monitored and did not reduce its overall service life.

Example 3

In the fleet presented in Table 4, honorary engine tests of 50,000 to 80,000 kilometers were carried out. New engines, carburetors, fuel tanks and intake manifolds are used in cars. Unleaded autobenzine (0.001 - 0.005 g Pb / l) with OCVM 95-97 having an MTBE content of 7-12% by volume, which was additive with 750 ppm of a dicarboxylic acid derivative according to the invention with structural chemical formula (I), was used as fuel.

-6GB 280251 B6

R 1 is -CH ₂ -CH-, X is sodium, Y is nitrogen, nh- (ch ₂ ch ₂ nh) ₂ -h

R ₂ is phenyl-, a = 1, b = 1, R ₃ is C ₁₂ H ₂₅ The dicarboxylic acid derivative was prepared by reacting the corresponding secondary amine with maleic anhydride followed by neutralization of the resulting intermediate with sodium hydroxide.

The additive of this composition was dissolved in an aromatic solvent having a boiling point of 140-190 ° C prior to addition to unleaded autobenzine such that the resulting solution contained 10% of the effect of the substance.

All vehicles were driven mainly in urban and highway traffic during the tests. After every 5,000 km, the clearance of the exhaust valves was checked, and the performance and emission characteristics of the vehicles, as well as their fuel economy and octane demand, were measured every 10,000 km. The efficiency of vehicles with catalytic converters was determined. After the tests, the engines hurt disassembled and comprehensively evaluated.

The evaluations have shown that the additive of the invention provides exhaust valve seats of all test vehicles a complete protection against their wear during the combustion of unleaded gasoline. The additive does not negatively affect the operation of the petrol engine or its service life. It is harmless to catalytic exhaust gas reading systems and does not impair petrol engine emissions.

Table 1

Site engine test conditions

Phase Test cycle composition Engine load Duration [min] Engine speed [l.min ^-1 ] 1. 20 May 3000 fully 2. 10 850 idle 3. 20 May 5000 fully 4. 10 850 idle

-7EN 280251 B6

Table 2

Effect of test duration on exhaust valve seat bore using lead free gasoline (0,000 g Pb / l) and additive-free according to the invention

Number Exhaust valve seat recess [mm] hours diameter for 4 cylinders one cylinder max. 12 0.26 0.35 24 0.45 0.60 36 0.80 1/19

Table 3

Effect of test duration on exhaust valve seat bore using 0.013 g Pb / l lead-free petrol and additive-free according to the invention

Number of hours Exhaust valve recess [mm] diameter per 4 cylinders one cylinder max. 12 24 36 0.12 0.23 0.32 0.54 0.43 0.76

Table 4

Car fleet used for honor engine tests

Type of vehicle Number of vehicles ŠKODA 120 L 3 ŠKODA 130 L 8 ŠKODA FAVORIT 136 L p Catalyst 4 VOLGA GAZ 2 OLTCIT 11 R 3

Industrial utilization.

The application of the dicarboxylic acid derivatives according to the invention to unleaded gasoline permits the continuous trouble-free operation of all petrol-powered cars on this more environmentally-friendly fuel and thus allows a virtually instantaneous transition from leaded gasoline to the production and use of unleaded fuel.

Claims (1)

Derivatives of dicarboxylic acids as additives to low or unleaded motor gasolines, which prevent the wear of exhaust valve seats in vehicles not designed to burn unleaded gasoline, characterized by having the structural chemical formula I: COOX / R (R ₂₎ \ / CO - Y \ ^(R3> b (AND in which it means R _{1 is a} divalent hydrocarbon function having a total carbon number of from 5 to 38, or a hydrocarbon function having a nitrogen atom in the amino group and / or an oxygen atom in a hydroxy and / or ether group having a total number of carbon atoms of 1 to 38; R ₂ is a monovalent hydrocarbon functional group having a carbon number from 1 to 42 or hydrogen, X hydrogen and / or an alkali metal and / or alkaline earth metal group, Y oxygen or nitrogen, a and b integers zero or 1, with a + b> 1, R _{3 is} hydrogen, or a monovalent hydroxy-substituted hydrocarbon function having a carbon number of 1 to 42, or a monovalent hydrocarbon function having a carbon number of 1 to 42, or a monovalent function having a structural chemical formula II or III or IV, - [- (CH ₂ ) _C -NH-] _d -R ₄ (II) (III) (IV) -9EN 280251 B6 in which R ( _{4) is} hydrogen or a monovalent hydrocarbon functional group having a carbon number of 1 to 42 or a functional group having structural chemical formula III, R _{5 is} hydrogen or a monovalent hydrocarbon function having a carbon number of 1 to 3, R _g is hydrogen or a functional group - (- CH-CH ₂ -O-) fH. C whole number from 1 to 10, d whole number from zero to 6, E whole number from 1 to 50, F whole number from 1 to 50. End of document