Title of Invention

FURNACE CARBON BLACK,PROCESS FOR ITS PRODUCTION AND ITS USE

Abstract

Furnace carbon black which has an H content of greater than 4000 ppm and a peak integral ratio of non-conjugated H atoms (1250-2000 cm-1) to aromatic and graphitic H atoms 10 (1000-1250 cm-1 and 750-1000 cm-1) of less than 1.22. It is produced by injecting the liquid carbon black raw material and the gaseous carbon black raw material at the same point in a furnace carbon black process. The furnace carbon black may be used in the preparation of electrocatalysts.

Full Text

1A Furnace carbon black, process for its production and its use 5 The invention relates to a furnace carbon black, to a process for its production and to its use. Furnace carbon blacks can be produced in a furnace carbon black reactor by the pyrolysis of hydrocarbons, as is known from Ullmanns Encyklopadie der technischen Chemie, 10 Volume 14, page 637-640 (1977). In the furnace carbon black reactor, a zone having a high energy density is produced by burning a fuel gas or a liquid fuel with air, and the carbon black raw material is injected into that zone. The carbon black raw material is pyrolysed at temperatures from 15 1200°C to 1900°C. The structure of the carbon black may be influenced by the presence of alkali metal or alkaline earth metal ions during the carbon black formation, and such additives are therefore frequently added in the form of aqueous solutions to the carbon black raw material. The 20 reaction is terminated by the injection of water (quenching) and the carbon black is separated from the waste gas by means of separators or filters. Because of its low bulk density, the resulting carbon black is then granulated. That may be carried out in a pelletising 25 machine with the addition of water to which small amounts of a pelletising auxiliary may be added. In the case of the simultaneous use of carbon black oil and gaseous hydrocarbons, such as, for example, methane, as the carbon black raw material, the gaseous hydrocarbons may be 30 injected into the stream of hot waste gas separately from the carbon black oil through their own set of gas lances. If the carbon black oil is divided between two different injection points which are offset relative to each other along the axis of the reactor, then at the first, upstream 990090 RS/AL 2 point, the amount of residual oxygen still contained in the combustion chamber waste gas is present in excess relative to the carbon black oil that is sprayed in. Accordingly, carbon black formation takes place at a higher temperature 5 at that point as compared with subsequent carbon black injection sites, that is to say the carbon blacks formed at the first injection point are always more finely divided and have a higher specific surface area than those formed at a subsequent injection point. Each further injection of 10 carbon black oils leads to further temperature reductions and to carbon blacks having larger primary particles. Carbon blacks produced in that manner therefore exhibit a broadening of the aggregate size distribution curve and, after incorporation into rubber, show different behaviour 15 than carbon blacks having a very narrow monomodal aggregate size spectrum. The broader aggregate size distribution curve leads to a lower loss factor of the rubber mixture, that is to say to a lower hysteresis, which is why one also speaks of low hysteresis carbon blacks. Carbon blacks of 20 that type, and processes for their production, are described in patent specifications EP 0 315 442 and EP 0 519 988. DE 19521565 discloses furnace carbon blacks having CTAB values from 80 to 180 m2/g and 24M4-DBP absorption from 80 25 to 140 ml/100 g, for which, in the case of incorporation into an SSBR/BR rubber mixture, a tan5o/tan86o ratio of tan50/tan§60 > 2.76 - 6.7 x 10~3 x CTAB applies and the tan8go value is always lower than the value for ASTM carbon blacks having the same CTAB surface area 30 and 24M4-DBP absorption. In that process, the fuel is burnt with a smoking flame in order to form seeds. The object of the present invention is to produce a carbon black that has a higher activity when used as a support material for electrocatalysts in fuel cells. 990090 RS/AL 3 The invention provides a furnace carbon black, characterised in that it has an H content of greater than 4000 ppm, determined by CHN analysis, and a peak integral ratio, determined by inelastic neutron scattering (INS), of 5 non-conjugated H atoms (1250-2000 cm"1) to aromatic and graphitic H atoms (1000-1250 cm"1 and 750-1000 cm"1) of less than 1.22. The H content may be greater than 4200 ppm, preferably greater than 4400 ppm. The peak integral ratio of non-10 conjugated H atoms {1250-2000 cm"1) to aromatic and graphitic H atoms (1000-1250 cm*1 and 750-1000 cm"1) may be less than 1.20. The CTAB surface area may be from 20 to 200 m2/g, preferably from 20 to 70 m2/g. The DBP number may be from 15 40 to 160 ml/100 g, preferably from 100 to 140 ml/100 g. The very high hydrogen content indicates a pronounced disturbance of the carbon lattice by an increased number of crystallite edges. The invention further provides a process for the production 20 of the furnace carbon black according to the invention in a carbon black reactor which contains, along the axis of the reactor, a combustion zone, a reaction zone and a termination zone, by producing a stream of hot waste gas in the combustion zone by completely burning a fuel in an 25 oxygen-containing gas and. passing the waste gas from the combustion zone through the reaction zone into the termination zone, mixing a carbon black raw material with the hot waste gas in the reaction zone and stopping the formation of carbon black in the termination zone by 30 spraying in water, which process is characterised in that a liquid carbon black raw material and a gaseous carbon black raw material are injected at the same point. 990090 RS/AL 4 The liquid carbon black raw material may be atomised by-pressure, steam, compressed air or the gaseous carbon black raw material. Liquid hydrocarbons burn more slowly than gaseous 5 hydrocarbons since they must first be converted into the gaseous form, that is to say vaporised. As a result, the carbon black contains components that are formed from the gas and components that are formed from the liquid. The so-called K factor is frequently used as the measured 10 value for characterising the excess of air. The K factor is the ratio of the amount of air required for stoichiometric combustion of the fuel to the amount of air actually supplied to the combustion. A K factor of 1, therefore, means stoichiometric combustion. Where there is an excess 15 of air, the K factor is less than 1. K factors of from 0.3 to 0.9 may be applied, as in the case of known carbon blacks. K factors of from 0.6 to 0.7 are preferably used. There may be used as the liquid carbon black raw material liquid aliphatic or aromatic, saturated or unsaturated 20 hydrocarbons or mixtures thereof, distillates from coal tar or residue oils which are formed in the catalytic cracking of crude oil fractions or in the production of olefins by cracking naphtha or gas oil. There may be used as the gaseous carbon black raw material 25 gaseous aliphatic, saturated or unsaturated hydrocarbons, mixtures thereof or natural gas. The described process is not limited to a particular reactor geometry. Rather, it may be adapted to different types of reactor and sizes of reactor. 30 The carbon black raw material atomisers used may be both pure mechanical atomisers {single-component atomisers) and two-component atomisers with internal or external mixing, it being possible for the gaseous carbon black raw material 990090 RS/AL 5 to be used as the atomising medium. The above-described combination of a liquid and a gaseous carbon black raw material may therefore be implemented, for example, by using the gaseous carbon black raw material as the 5 atomising medium for the liquid carbon black raw material. Two-component atomisers may preferably be used for atomising the liquid carbon black raw material. While in the case of single-component atomisers a change in the throughput may also lead to a change in the droplet size, 10 the droplet size in the case of two-component atomisers can be influenced largely independently of the throughput. Using the process according to the invention it is possible to produce the entire range of industrial furnace carbon blacks. The measures necessary therefor, such as, for 15 example, the setting of the dwell time in the reaction zone and the addition of additives to influence the structure of the carbon black, are known to the person skilled in the art. Examples 20 In the Examples and Comparison Examples that follow, furnace carbon blacks according to the invention are produced and their use as a support material for electrocatalysts is described. The electrochemical performance data in a fuel cell are used as the criterion 25 for evaluating the furnace carbon blacks. Production of carbon black Bl: A carbon black according to the invention is produced in the carbon black reactor 1 shown in Figure 1. The carbon black reactor 1 has a combustion chamber 2. The oil and gas 30 are introduced into the combustion chamber through the 990090 RS/AL 6 axial lance 3. The lance may be displaced in the axial direction in order to optimise carbon black formation. The combustion chamber leads to the narrow portion 4. After passing through the narrow portion, the reaction gas 5 mixture expands into the reaction chamber 5. The lance has suitable spray nozzles at its head {Figure 2). The combustion zone, the reaction zone and the termination zone, which are important for the process according to the 10 invention, cannot be separated sharply from one another. Their axial extent depends on the positioning of the lances and Of the quenching water lance 6 in each particular case. The dimensions of the reactor used are as indicated below: largest diameter of the combustion chamber: 696 mm 15 length of the combustion chamber to the narrow portion: 630 mm diameter of the narrow portion: 140 mm length of the narrow portion: 230 mm diameter of the reaction chamber: 802 mm 20 position of the oil lances 1J + 160 mm position of the quenching water lances 1J 2060 mm 11 measured from the zero point (beginning of the narrow portion) The reactor parameters for the production of the carbon 25 black according to the invention are listed in the table below. 990090 RS/AL 7 Reactor parameters Carbon black Parameter Unit Bl Combustion air Nm3/h 150"0 Combustion air temperature °C 550 X natural gas Nm3/h 156 k factor (total) 0.70 Carbon black oil, axial kg/h 670 Carbon black oil position mm + 16 Atomising vapour kg/h 100 Additive (K2CO3 solution) 1/h x g/1 5.0x3.0 Additive position axial Reactor outlet °C 749 Quenching position mm 9/8810 Characterisation of carbon black Bl: The hydrogen contents of the carbon blacks is determined by CHN elemental analysis (LECO RH-404 analyser with thermal 5 conductivity detector). The method of inelastic neutron scattering (INS) is described in the literature (P. Albers, G. Prescher, K. Seibold, D. K. Ross and F. Fillaux, Inelastic Neutron Scattering Study Of Proton Dynamics In Carbon Blacks, Carbon 34 (1996) 903 and P. Albers, 10 K. Seibold, G. Prescher, B. Freund, S. F. Parker, J. Tomkinson, D. K. Ross, F. Fillaux, Neutron Spectroscopic Investigations On Different Grades Of Modified Furnace Blacks And Gas Blacks, Carbon 37 (1999) 437). The INS (or IINS - inelastic incoherent neutron scattering) 15 method offers some quite unique advantages for the more intensive characterisation of carbon blacks and activated carbons, 990090 RS/AL 8 In addition to the proven elemental-analytical quantification of the H content, the INS method allows the in some cases very small hydrogen content in graphitised carbon blacks (about 100-250 ppm), carbon blacks (about 5 2000-4000 ppm in furnace carbon blacks) and in activated carbons (about 5000-12000 ppm in typical catalyst supports) to be broken down in greater detail in respect of its bond states. The table below lists the values of the total hydrogen 10 content of the carbon blacks, determined by CHN analysis (LECO RH-404 analyser with thermal conductivity detector). In addition, the spectra integrals are given, which are determined as follows: integration of the regions of an INS spectrum of 750-1000 cm"1 (A), 1000-1250 cm"1 (B) and 1250-15 2000 cm"1 (C). The aromatic and graphitic H atoms are formed by the sum of the peak integral A and B. The carbon blacks are introduced without further pretreatment into specially developed Al cuvettes (Al having a purity of 99.5 %, cuvette wall thickness 0.35 mm, 20 cuvette diameter 2.5 cm). The cuvettes are hermetically sealed (flange gasket from Kalrez 0-ring). 990090 RS/AL 9 Carbon black H content tppm] by CHN elemental analysis Peak integral by INS measurements A B C Ratio C/ (A+B) 750-lOOOcm"1 out of plane C-H-deformation vibration 1000-1250cm"1 in plane C-H-deformation vibration 1250-2000cm"i C-H-de formation vibration of non-conjugated constituents non-conjugated H atoms to aromatic and graphitic H atoms Bl 4580 ± 300 107 ± 1 99 ± 1 241 ± 3 1.17 N 234 3853 23.2 ± 1 21.4 ± 1 55 + 3 1.23 EB 111 DE 19521565 4189 27.4 ± 1 26.1 ± 1 68 ± 3 1.27 Vulcan XC-72 Furnace carbon black 2030 ± 200 69 ± 1 63 + 1 176 ± 3 1.33 Accordingly, Bl exhibits quantitatively more hydrogen relative to the other carbon blacks, but its sp3/sp2-H ratio is lower, that is to say the additional amount of 5 hydrogen is bonded especially aromatically/graphitically. They are C-H- protons at cleavage edges and defects saturated with hydrogen, and hence the surface is on average more greatly disturbed. Nevertheless, carbon black Bl, when considered in absolute terms, at the same time 10 also has the highest proportion of disturbed, non- 990090 RS/AL 10 conjugated constituents, without on the other hand - in relative terms - its sp3/sp2 nature being drastically-altered in the direction of sp3. The surface area ratio of the specific surface areas BET 5 adsorption by CTAB (cetylammonium bromide) adsorption is determined according to standard DIN 66 132. Carbon black CTAB surface area [m2/g] BET surface area CmVg] BET:CTAB surface area ratio Bl 30 30 1 Example 1 20.1 g of carbon black Bl (0.5 wt.% moisture) are suspended 10 in 2000 ml of demineralised water. After heating to 90°C and adjustment of the pH value to 9 using sodium hydrogen carbonate, 5 g of platinum in the form of hexachloro-platinic acid solution (25 wt.% Pt) are added, and the suspension is adjusted to pH 9 again, reduced with 6.8 ml 15 of formaldehyde solution (37 wt.%), washed, after filtration, with 2000 ml of demineralised water and dried in vacuo for 16 hours at 80°C. The resulting electro-catalyst has a platinum content of 20 wt.%. 990090 RS/AL 11 Comparison Example 1 Analogously to Example 1, 20.0 g of Vulcan XC-72 R (based on dry weight) from Cabot are suspended in 2000 ml of demineralised water. The electrocatalyst is prepared in the 5 same manner as described in Example 1. After drying in vacuo, an electrocatalyst having a platinum content of 20 wt.% is obtained. Example 2 A solution of 52.7 g of hexachloroplatinic acid (25 wt.% 10 Pt) and 48.4 g of ruthenium(III) chloride solution (14 wt.% Ru) in 200 ml of deionised water is added, with stirring, at room temperature, to a suspension of 80.4 g of carbon black Bl (0.5 wt.% moisture) in 2000 ml of demineralised water. The mixture is heated to 80°C and the pH value is 15 adjusted to 8.5 using sodium hydroxide solution. After the addition of 27.2 ml of a formaldehyde solution (37 wt.%), the mixture is filtered off and washed with 2000 ml of demineralised water, and the moist filter cake is dried at 80°C in a vacuum drying cabinet. An electrocatalyst 20 containing 13.2 wt.% platinum and 6.8 wt.% ruthenium is obtained. Comparison Example 2 Analogously to Example 2, using 81.1 g of Vulcan XC-72 R (1.39 wt.% moisture) as catalyst support, a 25 platinum/ruthenium catalyst containing 13.2 wt.% Pt and 6.8 wt.% Ru is obtained. 990090 RS/AL 12 The synthesis of Comparison Example 2 is described in DE 197 21 437 under Example 1. For the purpose of electrochemical characterisation, the electrocatalysts are processed to form a membrane electrode 5 assembly The cathode and anode catalysts are applied to an ion-conductive membrane (Nafion 115) according to Example 1 of the process described in US 5 861 222. The membrane so 15 coated is placed between two carbon papers (TORAY, TCG 90) which have been rendered hydrophobic in a conductive manner. The coating on the cathode and anode sides is in each case 0.25 mg of platinum/cm2. The resulting membrane electrode assembly (MEA) is measured in a PEM single cell 20 (pressureless operation, temperature 80°C) , a current density of 0.4 A/cm2 being set. For the electrochemical testing of the cathode catalysts, both sides of the membrane are coated with a paste of a platinum catalyst described under Example 1 or Comparison 2 5 Example 1. Oxygen or air is used as the fuel gas on the cathode, and hydrogen is used on the anode. 990090 RS/AL 13 Catalyst Cell performance at 400 mA/cm2 [mV] Cell performance at 500 mA/cm2 [mV] o2 air o2 air Example 1 687 606 649 545 Comparison Example 1 630 518 576 429 The preparation of a membrane electrode assembly for testing the anode catalyst is carried out completely analogously to the process according to US 5 861 222 5 described for the cathode catalysts. In that case, a supported Pt/Ru catalyst prepared according to Example 2 or Comparison Example 2 is used as the anode catalyst. On the cathode side, a platinum catalyst prepared according to Comparison Example 1 is used in both membrane 10 electrode assemblies. Measurement is carried out in a PEM single cell {operation under pressure at 3 bar, temperature 75°C) , a current density of 0.5 A/cm2 being set. The cell voltage U in hydrogen/oxygen operation (without 15 the metering in of reformate and/or CO on the anode side) is used as a measure of the catalyst activity. 990090 RS/AL 14 The voltage drop Au, which occurs after the metering in of 100 ppm of CO to the fuel gas, is used as a measure of the CO tolerance of the catalyst. The following fuel gas composition in reformate/CO 5 operation is used: 58 vol.% H2; 15 vol. % N2, 24 vol. % CO2, 3 vol.% air {"airbleed"). Catalyst H2/O2 operation: cell performance at 500 mA/cm2 [mV] Reformate/02 operation: cell performance at 500 mA/cm2 [mV] AU CO-induced voltage drop [mVJ Example 2 715 661 - 54 Comparison Example 2 686 620 - 66 The cell performance is markedly increased for Examples 1 and 2 as compared with the respective comparison examples. 15 WE CLAIM: 1. Furnace carbon black , characterised in that it has an H content of greater than 4000 ppm, determined fay CHN analysis, and a peak integral ratio, determined by inelastic neutron scattering (INS), of non- conjugated H atoms (1250-2000 cm"1) to aromatic and graphitic H atoms (10004250 cm"1 and 750-1000 cm"1) of less than 1.22. 2. Process for the production of furnace carbon black according to claim 1 in a carbon black reactor which contains, along the axis of the reactor, a combustion zone, a reaction zone and a termination zone, by producing a stream of hot waste gas in the combustion zone by completely burning a fuel in an oxygen- containing gas and passing the waste gas from the combustion zone through the reaction zone into the termination zone, mixing a carbon black raw material into the hot waste gas in the reaction zone and stopping carbon black formation in the termination zone by spraying in water, characterised in that a liquid carbon black raw materiai and a gaseous carbon black raw materiai are injected at the same point and the carbon black raw material is pyrolysed at temperatures from 1200°C to 1900°C and the K facter is from 0.3 to 0.9. 3. Process for preparation of an electrocatalyst which employs carbon black according to claim 1 as a carrier material for metal precipitation. Furnace carbon black which has an H content of greater than 4000 ppm and a peak integral ratio of non-conjugated H atoms (1250-2000 cm-1) to aromatic and graphitic H atoms 10 (1000-1250 cm-1 and 750-1000 cm-1) of less than 1.22. It is produced by injecting the liquid carbon black raw material and the gaseous carbon black raw material at the same point in a furnace carbon black process. The furnace carbon black may be used in the preparation of electrocatalysts.

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00486-cal-2000-correspondence.pdf

00486-cal-2000-description(complete).pdf

00486-cal-2000-drawings.pdf

00486-cal-2000-form-1.pdf

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00486-cal-2000-form-2.pdf

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00486-cal-2000-g.p.a.pdf

00486-cal-2000-letters patent.pdf

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486-CAL-2000-(01-10-2012)-CORRESPONDENCE.pdf

486-CAL-2000-(03-01-2013)-FORM-27.pdf

486-CAL-2000-ASSIGNMENT.pdf

486-CAL-2000-CORRESPONDENCE-1.1.pdf

486-CAL-2000-CORRESPONDENCE.pdf

486-CAL-2000-FORM 16.pdf

486-CAL-2000-FORM 27-1.1.pdf

486-CAL-2000-FORM 27..pdf

486-CAL-2000-FORM-27.pdf

486-CAL-2000-PA.pdf