Fuel additive composition containing a dispersion of iron particles and a detergent

Abstract

A composition contains an additive for assisting with regeneration of the PF in the form of an organic dispersion of iron particles in crystallized form and a detergent including a quaternary ammonium salt.

Claims

1. A composition comprising a dispersion and a detergent comprising a quaternary ammonia salt, said dispersion comprising: an organic phase; at least one amphiphilic agent, and solid objects dispersed in the organic phase, in the form of individualized particles or particle aggregates, consisting of an iron compound in crystallized form, such that said particles have an average size D.sub.XRD of less than or equal to 12 nm as measured by X-ray diffraction, the particles have a median diameter .sub.50 comprised between 3 nm and 12 nm, wherein said quaternary ammonia salt comprises a reaction product: (i) of at least one compound which may comprise: (a) the condensation product of an acylation agent with hydrocarbon substitution and of a compound comprising an oxygen or nitrogen atom capable of condensing the acylation agent, the condensation product having at least one tertiary amine function; (b) and amine with polyalkene substitution comprising at least one tertiary amine function; and (c) a Mannich reaction product comprising at least one tertiary amine function, the Mannich reaction product being derived from a phenol with hydrocarbon substitution, from an aldehyde and from an amine; and (ii) of a suitable quaternization agent for converting the tertiary amine function of the compound (i) into a quaternary nitrogen, and wherein the iron content is comprised between 0.05% and 25% by weight of iron metal based on the total weight of said composition.

2. The composition according to claim 1, further comprising an oxygenated detergent additive.

3. The composition according to claim 1, wherein the quaternary ammonium salt comprises the product of the reaction: (i) of the condensation product of an acylation agent with hydrocarbon substitution and of a compound comprising an oxygen or nitrogen atom capable of fusing the acylation agent, the condensation product having at least one tertiary amine function; and (ii) of a quaternization agent comprising dialkyl sulfates, benzyl halides, carbonates with hydrocarbon substitution, epoxides with hydrocarbon substitution in combination with an acid or mixtures thereof.

4. The composition according to claim 3, wherein the acylation agent with hydrocarbon substitution is succinic polyisobutylene anhydride and the compound including an oxygen or nitrogen atom capable of fusing said acylation agent is selected from dimethylaminopropylamine, N-methyl-1,3-diaminopropane, N,N-dimethylaminopropylamine, N,N-diethylaminopropylamine, N,N-dimethyl-aminoethylamine, diethylenetriamine, dipropylenetriamine, dibutylenetriamine, triethylenetetraamine, tetraethylenepentaamine, pentaethylenehexaamine, hexamethylenetetraamine and bis(hexamethylene)triamine.

5. The composition according to claim 1, wherein the oxygenated detergent additive is a polyisobutylene compound including a succinic anhydride or succinic acid head group.

6. The composition according to claim 1, wherein the average size D.sub.XRD of the particles is less than or equal to 8 nm.

7. The composition according to claim 1, wherein the organic phase of the dispersion is based on an apolar hydrocarbon.

8. The composition according to claim 1, wherein the amphiphilic agent is a carboxylic acid which generally includes from 10 to 50 carbon atoms.

9. The composition according to claim 1, wherein at least 80% by number of the particles have a size D.sub.TEM of less than or equal to 12 nm as measured by transmission microscopy.

10. The composition according to claim 1, wherein the solid objects of the invention have a hydrodynamic diameter D.sub.h of less than or equal to 50 nm as measured by dynamic light scattering.

11. The composition according to claim 1 wherein the molar ratio between the number of moles of amphiphilic agent and the number of moles of iron is comprised from 0.2 to 1.

12. A fuel additive for internal combustion engines consisting of the composition according to claim 1.

13. A method for preparing a composition comprising a step for putting into contact and mixing a detergent comprising a quaternary ammonium salt and a dispersion, wherein the dispersion comprises: an organic phase; at least one amphiphilic agent, and solid objects dispersed in the organic phase, in the form of individualized particles or particle aggregates, consisting of an iron compound in crystallized form, such that said particles have an average size D.sub.XRD of less than or equal to 12 nm as measured by X-ray diffraction, the particles have a median diameter .sub.50 comprised between 3 nm and 12 nm, wherein said quaternary ammonia salt comprises a reaction product: (i) of at least one compound which may comprise: (a) the condensation product of an acylation agent with hydrocarbon substitution and of a compound comprising an oxygen or nitrogen atom capable of condensing the acylation agent, the condensation product having at least one tertiary amine function; (b) and amine with polyalkene substitution comprising at least one tertiary amine function; and (c) a Mannich reaction product comprising at least one tertiary amine function, the Mannich reaction product being derived from a phenol with hydrocarbon substitution, from an aldehyde and from an amine; and (ii) of a suitable quaternization agent for converting the tertiary amine function of the compound (i) into a quaternary nitrogen, and wherein the iron content is comprised between 0.05% and 25% by weight of iron metal based on the total weight of said composition, whereby said composition is obtained.

14. An additived fuel comprising a fuel and a composition according to claim 1.

15. The additived fuel according to claim 14, wherein the fuel is selected from the group consisting of gas oils and biofuels.

16. The additived fuel according to claim 14, wherein the iron mass content is comprised from 1 to 50 ppm, of iron metal based on the total mass of the fuel.

17. A method for applying an internal combustion engine comprising a step for delivering to said engine a fuel and a composition according to claim 1.

18. A fuel additive for internal combustion engines consisting of a composition comprising a dispersion and a detergent comprising a quaternary ammonia salt, said dispersion comprising: an organic phase, only one amphiphilic agent, and solid objects dispersed in the organic phase in the form of individualized particles or particle aggregates, consisting of an iron compound in crystallized form, such that said particles have an average size D.sub.XRD of less than of equal of 12 nm measured by X-ray diffraction.

19. The fuel additive according to claim 18, wherein the amphiphilic agent is selected from the group consisting of: fatty acids of tall oil, soybean oil, tallow oil, lindseed oil, oleic acid, linoleic acid, stearic acid and its isomers, pelargonic acid, capric acid, lauric acid, myristic acid, dodecylbenzenesulfonic acid, ethyl-2-hexanoic acid, naphthenic acid, and hexanoic acid.

Description

EXAMPLES

Example 1: Preparation of the Dispersions

(1) Dispersion 1A

(2) Preparation of the Iron Precursor Solution

(3) One liter of solution is prepared in the following way: 576 g of Fe(NO.sub.3).sub.3 are mixed with 99.4 g of FeCl.sub.2, 4 H.sub.2O. The mixture is completed with distilled water in order to obtain one liter of solution. The final concentration of this solution of iron precursors is 1.5 mol.Math.L.sup.1 of Fe.

(4) Preparation of the Soda Solution

(5) A 6 mol.Math.L.sup.1 NaOH solution is prepared in the following way: 240 g of soda tablets are diluted in distilled water in order to obtain one liter of solution.

(6) In a one liter reactor equipped with a stirring system, a tank bottom consisting of 400 mL of sodium nitrate NaNO.sub.3 solution at 3 mol.Math.L.sup.1 is introduced. The pH of the solution is adjusted to 11 with a few drops of 6 mol/L soda. The formation of the precipitate is accomplished by simultaneous addition of the solution of iron precursors and of the soda solution prepared earlier. The introduction flow rates of both of these reagents are adjusted so that the pH is maintained constant and equal to 11 at room temperature.

(7) 823.8 g of the solution obtained by precipitation (i.e. 21.75 g of an Fe.sub.2O.sub.3 equivalent or further 0.27 moles of Fe), neutralized beforehand, are redispersed in a solution containing 24.1 g of isostearic acid (Prisorine 3501 provided by Croda) and 106.4 g of Isopar L. The suspension is introduced into a jacketed reactor equipped with a thermostated bath and provided with a stirrer. The reaction mixture is brought to 90 C. for 4 h.

(8) After cooling, the mixture is transferred into a test tube. Demixing is observed and a 500 mL aqueous phase and a 100 mL organic phase are collected.

(9) This organic dispersion has an iron mass content of 10%, expressed on the basis of iron metal, based on the total mass of the collected dispersions. The iron content is determined by X fluorescence analysis directly on the dispersion. This same technique is used in the following of the examples for monitoring the iron content.

(10) Dispersion 1B

(11) Preparation of the Iron Precursor Solution

(12) One liter of solution is prepared in the following way: 576 g of Fe(NO.sub.3).sub.3 are mixed with 99.4 g of FeCl.sub.2, 4 H.sub.2O. The mixture is completed with distilled water in order to obtain 1 liter of solution. The final concentration of iron precursors in this solution is 1.5 mol.Math.L.sup.1 of Fe.

(13) Preparation of the Soda Solution

(14) A 6 mol.Math.L.sup.1 NaOH solution is prepared in the following way: 240 g of soda tablets are diluted in distilled water in order to obtain one liter of solution.

(15) In a one liter reactor equipped with a stirring system, a tank bottom consisting of 400 mL of 3 mol.Math.L.sup.1 sodium nitrate NaNO.sub.3 solution is introduced. The pH of the solution is adjustable to 13 by a few drops of soda at 6 mol/L. The formation of the precipitate is accomplished by simultaneously adding the solution of iron precursors and the solution of soda prepared earlier. The introduction flow rates of both of these reagents are adjusted so that the pH is maintained constant and equal to 13 at room temperature.

(16) 823.8 g of the solution obtained by precipitation (i.e. 21.75 g of an Fe.sub.2O.sub.3 equivalent or further 0.27 moles of Fe) neutralized beforehand, are redispersed in a solution containing 24.1 g of istostearic acid (Prisorine 3501, a cut provided by Croda) and 106.4 g of Isopar L. The suspension is introduced into a jacketed reactor equipped with a thermostatic bath and provided with a stirrer. The reaction mixture is brought to 90 C. for 4 h.

(17) After cooling, the mixture is transferred into a test tube. Demixing is observed and a 500 mL aqueous phase and a 100 mL organic phase are collected.

(18) This organic dispersion has an iron mass content of 10% expressed in iron metal mass based on the total mass of the collected dispersion.

(19) Characterization by X-Ray Diffraction (XRD)

(20) XRD analysis of the dispersions of Example 1 was conducted according to the indications given in the description.

(21) It is seen that the peaks of the diffractograms of dispersion 1A and of dispersion 1B actually correspond to the characteristic XRD diffraction peaks of the crystallized magnetite and/or maghemite phase (sheet ICCD 01-088-0315).

(22) The calculation of the crystallite size according to the method shown earlier, leads to crystallite sizes of 9 nm for the dispersion 1A and 4 nm for the dispersion 1B, respectively.

(23) Characterization by Transmission Electron Microscopy (TEM)

(24) The TEM analysis was conducted according to indications given in the description.

(25) The characteristics stemming from this TEM counting: percentage of particles of less than 7 nm, .sub.50, polydispersity index P.sub.n as defined in the description are reported in Table 1.

(26) TABLE-US-00001 TABLE 1 Characterization by TEM of the dispersions of Example 1 % of particles <7 nm .sub.50 (nm) P.sub.n Dispersion 1A 72% 5.7 nm 0.35 Dispersion 1B 95% 3.8 nm 0.35
Characterization by Dynamic Light Scattering (DLS)

(27) The DLS analysis was conducted according to the indications given in the description.

(28) The average hydrodynamic diameters D.sub.h in intensity are reported in Table 2.

(29) TABLE-US-00002 TABLE 2 Characterization by DLS of dispersions of Example 1 D.sub.h (nm) Dispersion 1A 22 Dispersion 1B 11.6

Example 2: Preparation of the Detergent Compositions

Example 2A

(30) A detergent composition is prepared, consisting of a succinimide quaternary ammonium salt derived from dimethylaminopropylamine succinimide, from 2-ethylhexyl alcohol and from acetic acid, and it is subject to quaternization with propylene oxide and it is prepared by a method essentially similar to the one described in Example Q-1 above.

Example 2B

(31) A detergent composition is prepared by mixing 50 parts by weight of the succinimide quaternary ammonium salt of Example 2A with 18 parts by weight of an oxygenated detergent, all the parts by weight being calculated on a basis without any solvent. The mixing of the constituents is carried out under ambient conditions. The oxygenated detergent is a succinic polyisobutylene anhydride derived from polyisobutylene with a strong content of vinylidene of a number average molecular mass equal to 1,000 and from maleic anhydride and is prepared by a method essentially similar to the one described in Example O-1.

Example 2C

(32) A detergent composition is prepared according to the operating procedures of Example 2B, except that 35 parts by weight of the succinimide quaternary ammonium salt are used with 9 parts by weight of the oxygenated detergent, all the parts by weight being calculated on a basis without a solvent.

Example 2D

(33) A detergent composition is prepared according to the operating procedures of Example 2B, except that the oxygenated detergent is hydrolyzed by reaction with water, in order to form a succinic polyisobutylene acid prepared by a method essentially similar to the one described in Example O-2.

Example 2E

(34) A detergent composition is prepared according to the operating procedures of Example 1A, except that the succinimide quaternary ammonium salt is derived from dimethylaminopropylamine succinimide and from dimethyl sulfate and is prepared by a method essentially similar to the one described in Example Q-2, except that more solvent is present in order to obtain a mixture having an active substance level of 65% by weight in a petroleum naphtha solvent.

Example 2F

(35) A detergent composition is prepared according to the operating procedures of Example 2C, except that the oxygenated detergent is hydrolyzed by reaction with water, in order to form a succinic polyisobutylene acid prepared by a method essentially similar to the one described in Example O-2.

Example 3: Preparation of Fuel Additives Compositions

(36) Eight fuel additive compositions (3A to 3I) consisting in mixtures of the dispersions 1A or 1B of Example 1 and of the detergents of Examples 2A or 2F are prepared by mixing at room temperature each liquid in controlled proportions.

(37) Thus, 42.78 g of the dispersion 1A are mixed with 32.08 g of the detergent of Example 2F and 25.13 g of solvent, said solvent being a mixture of ISOPAR and of 2-ethylhexanol. The mixture is maintained with stirring at 120 rpm. The stirring of the mixture is maintained for 30 minutes and the quality of the mixture is monitored by measuring the iron content at the top and at the bottom of the obtained liquid.

(38) At the end of 30 minutes of stirring, the iron content at the top and at the bottom of the liquid is the same. This additive composition, subsequently called composition 3B, contains 4.3% by weight of iron metal.

(39) The other compositions are prepared in the same way by using controlled amounts of the dispersions 1A or 1B, detergents of Example 2A or 2F and an optional solvent.

(40) Table 3 shows the amounts of each component for the different compositions as well as their iron content.

(41) TABLE-US-00003 TABLE 3 composition of the additives and iron content dispersion (g) detergent (g) Mass compo- Example Example Example Example solvent % of sition 1A 1B 2A 2F (g) Fe 3A 100 10.0 3B 42.78 32.08 25.13 4.3 3C 53.50 26.03 20.47 5.4 3D 64.88 19.72 15.40 6.5 3E 42.84 32.12 25.03 4.3 3F 53.50 26.03 20.47 5.4 3G 65.29 19.72 15.30 6.5 3H 64.07 35.93 6.4 3I 73.27 26.73 7.3

Example 4: Stability of the Compositions in a Gasoil Fuel

(42) An additived fuel is prepared in order to measure the stability of the compositions according to the invention with said fuel. For this, a certain amount of composition is added to the fuel in order to reach a mass concentration of 7 ppm of iron metal in the fuel. The additived fuel is then continuously heated to 70 C. and the duration of stability of the additived composition is quantified.

(43) The additived composition is considered as stable when the iron content in the fuel has not decreased by more than 10%.

(44) The fuel used here is a fuel containing approximately 11% by mass of biofuel (fatty acid methyl ester or FAME) (Table 4).

(45) TABLE-US-00004 TABLE 4 Main characteristics of the B10 fuel Fuel Composition B10 Aromatic mass % 24 Polyaromatic mass % 4 FAME volume/volume % 10.8 Sulfur mg/kg 5 Carbon residue (on the 10% mass %/mass % <0.2 distillation residue) Copper mg/kg 0 Zinc mg/kg 0

(46) A specific amount of each of the additive compositions is added to 250 ml of fuel so as to obtain, after homogenization, 7 ppm of iron metal in the fuel and optional presence of one or several detergent molecules in the added composition: composition 3A: 14.8 mg composition 3B: 25.9 mg composition 3C, 22.0 mg composition 3D: 19.3 mg composition 3E: 25.9 mg composition 3F: 22.0 mg composition 3G: 19.2 mg composition 3H, 23.1 mg composition 3I: 20.2 mg.

(47) The time dependent change in the iron content in the fuel is quantified by regularly sampling a 20 ml volume of fuel in the upper portion of the fuel. This volume, once filtered to 0.2 m, is analyzed by X Fluorescence in order to determine the iron content.

(48) TABLE-US-00005 TABLE 5 Stability in the fuel at 70 C. (in days) Additived fuel Stability in the fuel composition 3A 1 composition 3B >50* composition 3C >50* composition 3D >50* composition 3E >50* composition 3F >50* composition 3G >50* composition 3H >50* composition 3I >50* * > x means that the test was voluntarily stopped after x days at 70 C., without observing over x days any significant change in the % of Fe

(49) It is seen (Table 5) that the compositions 3B to 3I according to the invention have a clearly increased stability relatively to the composition 3A without any detergent, since no decrease in the iron content is measured after 50 days of continuous heating at 70 C. of the additived fuels. The stability of the compositions according to the invention is therefore greater than 50 days at 70 C.

Example 5: Compatibility of the Fuel and of the Additive Compositions

(50) The compatibility of the fuel of the B10 type in Example 4 is measured with addition of the additive compositions of Example 3 (3A, 3B, 3C, 3D, 3E, 3F, and 3G).

(51) For this, a certain amount of dispersion is added to the fuel in order to reach a 7 ppm mass concentration of iron metal in the fuel, according to the same procedure as the one described in Example 4.

(52) The compatibility of the fuel was evaluated by using the NF EN 15751 standard (Fuels for automobilesFatty acid methyl esters (FAME) and mixtures with gas oilDetermination of the stability to oxidation by an accelerated oxidation method).

(53) For this test, a dry air flow (10 Uh) bubbles in 7.5 g of the fuel heated to 110 C. The vapors produced during the oxidation process are carried away by the air into a cell containing demineralized water and an electrode measuring the conductivity of water. This electrode is connected to a measurement and recording system. This system indicates the end of the induction period when the conductivity of the water rapidly increases. This rapid increase in the conductivity is caused by solubilization in the water of the volatile carboxylic acids formed during the oxidation process of the fuel.

(54) Table 6 shows that in the presence of the compositions containing a detergent containing at least one quaternary ammonium salt (compositions 3B to 3I), the induction time of the additived fuel is greater than for the additived fuel of the composition 3A alone (not containing any detergent of the quaternary ammonium type), which expresses less oxidation of the fuel and thus better compatibility.

(55) TABLE-US-00006 TABLE 6 Induction time of the fuel with and without FBC Induction time (h) composition 3A 35.6 composition 3B 42.2 composition 3C 40.9 composition 3D 39.8 composition 3E 41.7 composition 3F 39.8 composition 3G 37.9 composition 3H 37.4 composition 3I 36.7

Example 6: Engine Test for Regeneration of a Particle Filter

(56) The efficiency of the dispersions described in the preceding examples for regenerating a particle filter (PF) was measured through engine tests for regenerating PFs. For this, a diesel engine provided by the Volkswagen group (4 cylinders, 2 liters, turbocompressor with air cooling, 81 kW) was used on an engine test bench.

(57) The exhaust line mounted downstream is a commercial line consisting of an oxidation catalyst containing a washcoat based on platinum and aluminum followed by a PF in silicon carbide (PF: total volume 2.52 L, diameter 5.66 inches, length 5.87 inches).

(58) The fuel used is a commercial fuel meeting the EN590 DIN 51628 standard, containing less than 10 ppm of sulfur and containing 7% by volume of FAME.

(59) For these tests, the fuel is additived with different compositions 3B and 3E of Example 3. The added composition content is adjusted so as to add into the fuel a composition amount corresponding to 7 ppm by weight (composition 3B) or 5 ppm by weight (composition 3E) of iron expressed in the form of iron metal based on the total mass of fuel. As a comparison, a third test was conducted with the same fuel but not additived with any composition.

(60) The test is conducted in two successive steps: a step for loading the PF, followed by a step for regenerating the latter. The conditions of both of these steps are strictly identical for the three tests, except for the fuel used (either additived or not).

(61) The loading phase is carried out by running the engine at a speed of 3000 revolutions/min (rpm) and by using a torque of 45 Nm for approximately 6 hours. This loading phase is stopped when 12 g of particulate phases are loaded in the PF. During this phase, the temperature of the gases upstream from the PF is from 230 to 235 C. Under these conditions, the emissions of particles are of about 2 g/h.

(62) After this loading phase, the PF is disassembled and weighed in order to check the mass of particles loaded during this phase (particulate phase amount in the PF after loading from Table 7).

(63) The PF is then reassembled on the bench and reheated with the engine which is put back for 30 minutes under the operating conditions of the loading (3,000 rpm/45 Nm).

(64) The conditions of the engine are then modified (torque 80 Nm/2,000 rpm) and post-injection is required from the electronic central unit of the engine (ECU), which allows a rise in temperature upstream from the PF to 450 C. and starting the regeneration of the PF. These conditions are maintained for 35 minutes (2100 seconds), this time being counted from the starting of the post-injection.

(65) The PF regeneration efficiency is measured through two parameters: the % of burned soots, which corresponds to the combustion rate of soots calculated at each instant t according to the reduction in the pressure drop P(t):

(66) $\%\mathrm{burnt}\mathrm{soots}=\frac{P\left(\mathrm{beginning}\mathrm{of}\mathrm{regeneration}\right)-P\left(t\right)}{P\left(\mathrm{beginning}\mathrm{of}\mathrm{regeneration}\right)}100$ 100% of burnt soots corresponding to the stabilization of the pressure drop to the lowest level observed under these conditions with an PF not containing any soots. In the case of the tests conducted with the additived fuel, the pressure drop stabilizes before the end of the regeneration test which gives the possibility of calculating this criterion. In the case of the test with the non-additived fuel, the pressure drop remains high and is not stabilized which does not allow this criterion to be calculated. the mass of burnt particles during regeneration, calculated from the weighing operations of the PF before loading, after loading and at the end of the regeneration.

(67) Generally, the higher these parameters, the more the regeneration is efficient.

(68) The results are grouped in Table 7

(69) TABLE-US-00007 TABLE 7 Presence of an additive in the fuel aucun 3B 3E Iron content in the fuel (ppm by weight of Fe) 0 7 5 Amount of particulate phase in the PF after 12.2 12.4 12.0 loading (g) Amount of iron in the PF resulting from the 0 0.18 0.12 additive (g)* Particles burnt during the regeneration 2.2 12.0 11.5 (35 minutes) (g) Particles burnt during the regeneration 18 97 96 (35 minutes) (%) Pressure drop at the beginning of the 87.1 82.1 85.9 regeneration (mbars) Pressure drop after 35 minutes at 450 C. 65.6 30.4 30.3 (mbars) % of burnt soots after 5 minutes of regeneration 43.4 45.9 % of burnt soots after 10 minutes of 82.8 83.7 regeneration % of burnt soots after 15 minutes of 95.3 95.0 regeneration % of burnt soots after 20 minutes of 98.7 98.1 regeneration % of burnt soots after 35 minutes of 100 100 regeneration *calculated considering a loading of the PF for 6 hours with a fuel consumption of 4 kg/h

(70) It is seen that the presence of an additive in the fuel gives the possibility of obtaining regeneration of the PF at 450 C. since 96 to 97% of the soots are burnt after 35 minutes at 450 C. while in the absence of the additive only 18% of the soots are burnt. The same applies if the pressure drop is observed on the PF which is more greatly reduced in the presence of an additive: it drops in both cases from about 83-86 mbars to about 30 mbars while without any additive, the pressure drop after 35 minutes at 450 C. remains greater than 65 mbars expressing incomplete regeneration.

(71) When the compositions 3B and 3E are compared, it is seen that both compositions lead to closely related combustion kinetics if the time-dependent change of the pressure drop is observed at different times through the calculation of the percent of burnt soots (5, 10, 15, 20 or 35 minutes) of the regeneration at 450 C. However, this efficiency is obtained with a smaller amount of additive (5 ppm of iron metal here) for the additive prepared from the dispersion containing crystallites of the magnetite and/or maghemite type of smaller size (4 nm here for composition 3E). When the size of the crystallites is 9 nm (composition 3B), the amount to be introduced corresponds to an iron metal content of 7 ppm by weight.

(72) The whole of the Examples illustrates that the compositions containing crystallites of the magnetite and/or maghemite type of small size (typically 4 nm) may be highly effective at a low dosage while not notably degrading the fuel.