CA2143236A1 - Preparation of finely divided tin dioxide powders - Google Patents
Preparation of finely divided tin dioxide powdersInfo
- Publication number
- CA2143236A1 CA2143236A1 CA 2143236 CA2143236A CA2143236A1 CA 2143236 A1 CA2143236 A1 CA 2143236A1 CA 2143236 CA2143236 CA 2143236 CA 2143236 A CA2143236 A CA 2143236A CA 2143236 A1 CA2143236 A1 CA 2143236A1
- Authority
- CA
- Canada
- Prior art keywords
- tin
- finely divided
- gas
- tin dioxide
- preparation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 239000000843 powder Substances 0.000 title claims abstract description 13
- 238000002360 preparation method Methods 0.000 title claims description 8
- 150000001875 compounds Chemical class 0.000 claims abstract description 8
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 5
- 238000006864 oxidative decomposition reaction Methods 0.000 claims abstract description 5
- 150000003606 tin compounds Chemical class 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 16
- 239000007789 gas Substances 0.000 claims description 10
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 239000011261 inert gas Substances 0.000 claims description 5
- AFCAKJKUYFLYFK-UHFFFAOYSA-N tetrabutyltin Chemical compound CCCC[Sn](CCCC)(CCCC)CCCC AFCAKJKUYFLYFK-UHFFFAOYSA-N 0.000 claims description 3
- 125000004432 carbon atom Chemical group C* 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 239000002245 particle Substances 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 239000002912 waste gas Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000012043 crude product Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 150000003254 radicals Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 125000003342 alkenyl group Chemical group 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 239000004753 textile Substances 0.000 description 2
- 125000004178 (C1-C4) alkyl group Chemical group 0.000 description 1
- 125000004169 (C1-C6) alkyl group Chemical group 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- 125000000882 C2-C6 alkenyl group Chemical group 0.000 description 1
- 101100149686 Caenorhabditis elegans snr-4 gene Proteins 0.000 description 1
- 101100114416 Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987) con-10 gene Proteins 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910021627 Tin(IV) chloride Inorganic materials 0.000 description 1
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 150000005840 aryl radicals Chemical class 0.000 description 1
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- LCGVYMRFNOWPGQ-UHFFFAOYSA-N dibutyl-bis(prop-2-enyl)stannane Chemical compound CCCC[Sn](CC=C)(CC=C)CCCC LCGVYMRFNOWPGQ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 238000010327 methods by industry Methods 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical class C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- RWWNQEOPUOCKGR-UHFFFAOYSA-N tetraethyltin Chemical compound CC[Sn](CC)(CC)CC RWWNQEOPUOCKGR-UHFFFAOYSA-N 0.000 description 1
- XJPKDRJZNZMJQM-UHFFFAOYSA-N tetrakis(prop-2-enyl)stannane Chemical compound C=CC[Sn](CC=C)(CC=C)CC=C XJPKDRJZNZMJQM-UHFFFAOYSA-N 0.000 description 1
- VXKWYPOMXBVZSJ-UHFFFAOYSA-N tetramethyltin Chemical compound C[Sn](C)(C)C VXKWYPOMXBVZSJ-UHFFFAOYSA-N 0.000 description 1
- JEHHMOWXLBXVHN-UHFFFAOYSA-N tetrapentylstannane Chemical compound CCCCC[Sn](CCCCC)(CCCCC)CCCCC JEHHMOWXLBXVHN-UHFFFAOYSA-N 0.000 description 1
- CRHIAMBJMSSNNM-UHFFFAOYSA-N tetraphenylstannane Chemical compound C1=CC=CC=C1[Sn](C=1C=CC=CC=1)(C=1C=CC=CC=1)C1=CC=CC=C1 CRHIAMBJMSSNNM-UHFFFAOYSA-N 0.000 description 1
- OIQCWAIEHVRCCG-UHFFFAOYSA-N tetrapropylstannane Chemical compound CCC[Sn](CCC)(CCC)CCC OIQCWAIEHVRCCG-UHFFFAOYSA-N 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000004627 transmission electron microscopy Methods 0.000 description 1
- DBGVGMSCBYYSLD-UHFFFAOYSA-N tributylstannane Chemical compound CCCC[SnH](CCCC)CCCC DBGVGMSCBYYSLD-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
- C01B13/14—Methods for preparing oxides or hydroxides in general
- C01B13/20—Methods for preparing oxides or hydroxides in general by oxidation of elements in the gaseous state; by oxidation or hydrolysis of compounds in the gaseous state
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G19/00—Compounds of tin
- C01G19/02—Oxides
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Catalysts (AREA)
- Paints Or Removers (AREA)
Abstract
Finely divided tin dioxide powders are prepared by gas-phase decomposition of volatile tin compounds by subjecting organotin compounds to oxidative decomposition.
Description
. 2143236 -Preparation of finely divided tin dioxide powders The present invention relates to a novel process for the prepara-5 tion of finely divided tin dioxide powders by gas-phase decom-position of volatile tin compounds.
Finely divided tin dioxide powder having particle sizes of about ~ m is of interest for many applications, for example as a con-10 ductive pigment for coatings and plastics, as an additive in glazes, surface coatings, paper and textiles and especially as an additive for electrostatic toners, where it can be used as a charge controlling agent (CCA), for improving the flow of the toner and for preventing toner impaction, ie. adhesion of the 15 surface of the carrier particles with toner particles.
US-A-5 194 356 discloses a process for the preparation of finely divided tin dioxide, in which gaseous tin tetrachloride is hydro-lyzed in a flame of hydrogen, oxygen and nitrogen. This gives, as 20 a rule, hydrophilic products which are unsatisfactory, especially for electrostatic applications. In addition, hydrochloric acid is formed in the waste gas and has a highly corrosive effect and is difficult to remove from the reaction product.
25 FR-A-2 606 395 proposes a process for the preparation of finely divided metal oxides by gas-phase oxidation of suitable starting compounds at high temperatures. However, more precise information is provided only for the preparation of titanium dioxide, iron oxide and zirconium dioxide from the chlorides.
It is an object of the present invention to remedy the stated deficiencies and to permit the preparation of finely divided, hydrophobic tin dioxide powder in an advantageous manner.
35 We have found that this object is achieved by a process for the preparation of finely divided tin dioxide powders by gas-phase decomposition of volatile tin compounds, which comprises sub-jecting organotin compounds to oxidative decomposition.
40 Compounds of the formula SnR4, where the radicals R are identical or different and are each alkyl, alkenyl or aryl, for example tin tetraalkyls, tin tetraalkenyls and tin tetraaryls, and mixed tin aryl alkyls and tin alkyl alkenyls, are particularly suitable for this purpose.
~1~3236 The number of carbon atoms in the alkyl, alkenyl and aryl radi-cals is in principle unimportant, but compounds which have a suf-ficiently high vapor pressure at up to about 250 C are preferred, in order to ensure easy vaporization.
Accordingly, in the case of tin organyls having 4 identical radi-cals R, C1-C6-alkyl, especially C1-C4-alkyl, C2-C6-alkenyl, espe-cially allyl, and phenyl are particularly preferred.
10 Finally, dinuclear or polynuclear tin organyls, which may be bridged, for example, by oxygen atoms, may also be used.
Examples of suitable organotin compounds are diallyldibutyltin, tetraallyltin, tetraamyltin, tetra-n-propyltin, tetraethyltin, 15 tetraphenyltin, bis~tri-n-butyltin) oxide and especially tetra-n-butyltin and tetramethyltin.
The oxidizing gas used is in particular air or another oxygen/
inert gas mixture, but it is also possible to use ozone or nit-20 rous oxide.
The novel process is usually carried out at from 300 to 1000 C,preferably from 350 to 800 C, particularly preferably from 400 to 700 C.
The temperature and also the amount of oxygen are advantageously chosen so that the oxidation of the organic radicals to carbon dioxide and water is as complete as possible. If in fact the amount of oxygen introduced is less than the stoichiometrically 30 required amount, depending on the chosen temperature either the tin organyl is only partially decomposed and then condenses in the waste gas region, or soot and other decomposition products form.
35 With regard to the process engineering, the novel process is ad-vantageously carried out as follows:
The tin organyls are transferred from an evaporator vessel kept at from 20 C to the boiling point of the particular tin organyl, 40 with the aid of an inert gas, such as nitrogen or argon, via a nozzle into the heated reactor. The oxidizing gas is fed in via a separate feed line. Suitable reactors are stationary or moving tube reactors or bulb reactors.
45 The tin dioxide particles formed are discharged with the waste gas stream from the reactor and can be separated off in a suit-able filter, for example a large-area glass filter plate or filter cloth, which is to be cleaned with a gas stream, or in a cyclone (preferably a plurality of successive cyclones).
It has proven advantageous to condense the steam formed in the 5 oxidation out of the waste gas stream before the tin dioxide is separated off. For example, water-cooled metal coil condensers are suitable for this purpose.
In a preferred embodiment of the novel process, the finely di-10 vided tin dioxide obtained is furthermore subjected to a thermal aftertreatment with the introduction of a gas stream, in which aftertreatment undesirable byproducts, such as unconverted tin organyls and carbon, whose presence could not be prevented, are removed.
Gases suitable for this purpose are, for example, inert gases, such as nitrogen and air or other oxygen/inert gas mixtures.
The flow rate of the gas is preferably chosen so that the gas in 20 the reactor is exchanged from 5 to 200 times, in particular about 100 times, in 1 hour.
The aftertreatment is advantageously carried out at from 200 to 700 C, preferably from 400 to 700 C, and takes as a rule from 0.5 25 to 4 hours.
The finely divided tin dioxide powders prepared with the aid of the novel process have mean particle sizes of, usually, from 10 to 50 nm, it being possible for the m; n;mtlm particle size to be 30 about 1 nm and the m~Y;mllm particle size about 100 nm (determined by transmission electron microscopy~. These numerical values are also applicable to tin dioxide thermally aftertreated at 5 700 C, which surprisingly shows no particle growth. The tin content of the tin dioxides prepared according to the invention is as a rule 35 >78% by weight (determined by atomic absorption spectroscopy) and thus corresponds to the theoretical value of 78.76% by weight.
The carbon content of the product which has not been aftertreated may be up to 0.5% by weight, owing to adhering byproducts or 40 undecomposed starting materials. As a result of the thermal aftertreatment, the carbon content decreases to <0.1% by weight.
At the same time, a color change from in general pale gray to pale beige or white is observed.
45 The tin dioxide powders prepared according to the invention, in the form of the crude product and as aftertreated product, are hydrophobic and float in water. They are crystAll;ne and exhibit 21~3236 -_ 4 the diffraction pattern of tetragonal cassiterite in the X-ray powder pattern.
The finely divided tin dioxide powders prepared with the aid of 5 the novel process have a wide range of uses, for example as con-ductive pigments in coatings and plastics and as additives in glazes, surface coatings, paper and textiles and, owing to their conductivity and their hydrophobic character, are also particu-. larly suitable as additives for electrostatic toners (CCA, flow 10 improvers).
Example The reactor used was a 500 ml quartz glass flask which rotated at 15 30 rpm on a rotary evaporator drive and was present in an elec-tric tilting oven heated to 600 C (temperature inside the flask:
560-C).
100 ml (148 g) of tetrabutyltin were transferred with 50 l/h of 20 nitrogen from an evaporator vessel heated to 190 C, via a metallic pipe likewise thermostatted at 190 C, in the course of 6 hours, through the neck of the flask and into the flask. 100 l/h of air for oxidation were introduced via a second pipe.
25 In order to condense the water of reaction, the waste gas stream was first passed over a water-cooled metal coil condenser.
The major part of the tin dioxide present in the waste gas stream collected in the downstream 3 1 glass vessel having a D3 glass 30 filter plate.
The crude product formed was pale gray and was then transferred to a second, similar reactor and heated for 1 hour at 650 C in a stream of 100 l/h of nitrogen. The cooled aftertreated product 35 had a pale beige color.
40.57 g of tin dioxide powder having a mean particle size of 20 nm and a specific surface area (BET) of 47 m2/g were obtained.
40 The following results were obtained in an elemental analysis:
Crude product: 78.5% by weight of tin 0.2% by weight of carbon aftertreated product: 78.7% by weight of tin <0.1% by weight of carbon
Finely divided tin dioxide powder having particle sizes of about ~ m is of interest for many applications, for example as a con-10 ductive pigment for coatings and plastics, as an additive in glazes, surface coatings, paper and textiles and especially as an additive for electrostatic toners, where it can be used as a charge controlling agent (CCA), for improving the flow of the toner and for preventing toner impaction, ie. adhesion of the 15 surface of the carrier particles with toner particles.
US-A-5 194 356 discloses a process for the preparation of finely divided tin dioxide, in which gaseous tin tetrachloride is hydro-lyzed in a flame of hydrogen, oxygen and nitrogen. This gives, as 20 a rule, hydrophilic products which are unsatisfactory, especially for electrostatic applications. In addition, hydrochloric acid is formed in the waste gas and has a highly corrosive effect and is difficult to remove from the reaction product.
25 FR-A-2 606 395 proposes a process for the preparation of finely divided metal oxides by gas-phase oxidation of suitable starting compounds at high temperatures. However, more precise information is provided only for the preparation of titanium dioxide, iron oxide and zirconium dioxide from the chlorides.
It is an object of the present invention to remedy the stated deficiencies and to permit the preparation of finely divided, hydrophobic tin dioxide powder in an advantageous manner.
35 We have found that this object is achieved by a process for the preparation of finely divided tin dioxide powders by gas-phase decomposition of volatile tin compounds, which comprises sub-jecting organotin compounds to oxidative decomposition.
40 Compounds of the formula SnR4, where the radicals R are identical or different and are each alkyl, alkenyl or aryl, for example tin tetraalkyls, tin tetraalkenyls and tin tetraaryls, and mixed tin aryl alkyls and tin alkyl alkenyls, are particularly suitable for this purpose.
~1~3236 The number of carbon atoms in the alkyl, alkenyl and aryl radi-cals is in principle unimportant, but compounds which have a suf-ficiently high vapor pressure at up to about 250 C are preferred, in order to ensure easy vaporization.
Accordingly, in the case of tin organyls having 4 identical radi-cals R, C1-C6-alkyl, especially C1-C4-alkyl, C2-C6-alkenyl, espe-cially allyl, and phenyl are particularly preferred.
10 Finally, dinuclear or polynuclear tin organyls, which may be bridged, for example, by oxygen atoms, may also be used.
Examples of suitable organotin compounds are diallyldibutyltin, tetraallyltin, tetraamyltin, tetra-n-propyltin, tetraethyltin, 15 tetraphenyltin, bis~tri-n-butyltin) oxide and especially tetra-n-butyltin and tetramethyltin.
The oxidizing gas used is in particular air or another oxygen/
inert gas mixture, but it is also possible to use ozone or nit-20 rous oxide.
The novel process is usually carried out at from 300 to 1000 C,preferably from 350 to 800 C, particularly preferably from 400 to 700 C.
The temperature and also the amount of oxygen are advantageously chosen so that the oxidation of the organic radicals to carbon dioxide and water is as complete as possible. If in fact the amount of oxygen introduced is less than the stoichiometrically 30 required amount, depending on the chosen temperature either the tin organyl is only partially decomposed and then condenses in the waste gas region, or soot and other decomposition products form.
35 With regard to the process engineering, the novel process is ad-vantageously carried out as follows:
The tin organyls are transferred from an evaporator vessel kept at from 20 C to the boiling point of the particular tin organyl, 40 with the aid of an inert gas, such as nitrogen or argon, via a nozzle into the heated reactor. The oxidizing gas is fed in via a separate feed line. Suitable reactors are stationary or moving tube reactors or bulb reactors.
45 The tin dioxide particles formed are discharged with the waste gas stream from the reactor and can be separated off in a suit-able filter, for example a large-area glass filter plate or filter cloth, which is to be cleaned with a gas stream, or in a cyclone (preferably a plurality of successive cyclones).
It has proven advantageous to condense the steam formed in the 5 oxidation out of the waste gas stream before the tin dioxide is separated off. For example, water-cooled metal coil condensers are suitable for this purpose.
In a preferred embodiment of the novel process, the finely di-10 vided tin dioxide obtained is furthermore subjected to a thermal aftertreatment with the introduction of a gas stream, in which aftertreatment undesirable byproducts, such as unconverted tin organyls and carbon, whose presence could not be prevented, are removed.
Gases suitable for this purpose are, for example, inert gases, such as nitrogen and air or other oxygen/inert gas mixtures.
The flow rate of the gas is preferably chosen so that the gas in 20 the reactor is exchanged from 5 to 200 times, in particular about 100 times, in 1 hour.
The aftertreatment is advantageously carried out at from 200 to 700 C, preferably from 400 to 700 C, and takes as a rule from 0.5 25 to 4 hours.
The finely divided tin dioxide powders prepared with the aid of the novel process have mean particle sizes of, usually, from 10 to 50 nm, it being possible for the m; n;mtlm particle size to be 30 about 1 nm and the m~Y;mllm particle size about 100 nm (determined by transmission electron microscopy~. These numerical values are also applicable to tin dioxide thermally aftertreated at 5 700 C, which surprisingly shows no particle growth. The tin content of the tin dioxides prepared according to the invention is as a rule 35 >78% by weight (determined by atomic absorption spectroscopy) and thus corresponds to the theoretical value of 78.76% by weight.
The carbon content of the product which has not been aftertreated may be up to 0.5% by weight, owing to adhering byproducts or 40 undecomposed starting materials. As a result of the thermal aftertreatment, the carbon content decreases to <0.1% by weight.
At the same time, a color change from in general pale gray to pale beige or white is observed.
45 The tin dioxide powders prepared according to the invention, in the form of the crude product and as aftertreated product, are hydrophobic and float in water. They are crystAll;ne and exhibit 21~3236 -_ 4 the diffraction pattern of tetragonal cassiterite in the X-ray powder pattern.
The finely divided tin dioxide powders prepared with the aid of 5 the novel process have a wide range of uses, for example as con-ductive pigments in coatings and plastics and as additives in glazes, surface coatings, paper and textiles and, owing to their conductivity and their hydrophobic character, are also particu-. larly suitable as additives for electrostatic toners (CCA, flow 10 improvers).
Example The reactor used was a 500 ml quartz glass flask which rotated at 15 30 rpm on a rotary evaporator drive and was present in an elec-tric tilting oven heated to 600 C (temperature inside the flask:
560-C).
100 ml (148 g) of tetrabutyltin were transferred with 50 l/h of 20 nitrogen from an evaporator vessel heated to 190 C, via a metallic pipe likewise thermostatted at 190 C, in the course of 6 hours, through the neck of the flask and into the flask. 100 l/h of air for oxidation were introduced via a second pipe.
25 In order to condense the water of reaction, the waste gas stream was first passed over a water-cooled metal coil condenser.
The major part of the tin dioxide present in the waste gas stream collected in the downstream 3 1 glass vessel having a D3 glass 30 filter plate.
The crude product formed was pale gray and was then transferred to a second, similar reactor and heated for 1 hour at 650 C in a stream of 100 l/h of nitrogen. The cooled aftertreated product 35 had a pale beige color.
40.57 g of tin dioxide powder having a mean particle size of 20 nm and a specific surface area (BET) of 47 m2/g were obtained.
40 The following results were obtained in an elemental analysis:
Crude product: 78.5% by weight of tin 0.2% by weight of carbon aftertreated product: 78.7% by weight of tin <0.1% by weight of carbon
Claims (7)
1. A process for the preparation of finely divided tin dioxide powders by gas-phase decomposition of volatile tin compounds, which comprises subjecting organotin compounds to oxidative decomposition.
2. A process as claimed in claim 1, wherein the organotin com-pounds used are tin tetraalkyls, tin tetraalkenyls and/or tin tetraaryls in which each of the four organic radicals may contain up to 6 carbon atoms.
3. A process as claimed in claim 1, wherein the organotin com-pound used is tetra-n-butyltin.
4. A process as claimed in claim 1, wherein an oxygen-containing gas is used for the oxidative decomposition.
5. A process as claimed in claim 1, which is carried out at from 300 to 1000°C.
6. A process as claimed in claim 1, wherein the product obtained in the oxidative decomposition is subjected to a thermal aftertreatment at from 200 to 700°C with the introduction of a gas stream.
7. A process as claimed in claim 6, wherein the gas stream used is an inert gas or air stream.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19944406786 DE4406786A1 (en) | 1994-03-02 | 1994-03-02 | Process for the production of finely divided tin dioxide powders |
| DEP4406786.0 | 1994-03-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2143236A1 true CA2143236A1 (en) | 1995-09-03 |
Family
ID=6511597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2143236 Abandoned CA2143236A1 (en) | 1994-03-02 | 1995-02-23 | Preparation of finely divided tin dioxide powders |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0670287A1 (en) |
| JP (1) | JPH07267639A (en) |
| BR (1) | BR9500734A (en) |
| CA (1) | CA2143236A1 (en) |
| DE (1) | DE4406786A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6521297B2 (en) | 2000-06-01 | 2003-02-18 | Xerox Corporation | Marking material and ballistic aerosol marking process for the use thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10129376A1 (en) * | 2001-06-20 | 2003-01-09 | Degussa | Indium Tin Oxide |
| CN103318951B (en) * | 2013-07-10 | 2015-05-20 | 赵宝勤 | Preparation method of ATO (Antimony doped Tin Oxide) nanopowder |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2606395B1 (en) * | 1986-11-07 | 1990-09-14 | Air Liquide | PROCESS FOR THE PREPARATION OF SUBMICRONIC OXIDE POWDER AND APPARATUS FOR IMPLEMENTING SAME |
| US5075090A (en) * | 1988-01-12 | 1991-12-24 | Vista Chemical Company | Process for preparing small particle size mixed metal oxides |
-
1994
- 1994-03-02 DE DE19944406786 patent/DE4406786A1/en not_active Withdrawn
-
1995
- 1995-02-21 EP EP95102389A patent/EP0670287A1/en not_active Withdrawn
- 1995-02-22 BR BR9500734A patent/BR9500734A/en not_active Application Discontinuation
- 1995-02-23 CA CA 2143236 patent/CA2143236A1/en not_active Abandoned
- 1995-03-02 JP JP4326695A patent/JPH07267639A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6521297B2 (en) | 2000-06-01 | 2003-02-18 | Xerox Corporation | Marking material and ballistic aerosol marking process for the use thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0670287A1 (en) | 1995-09-06 |
| DE4406786A1 (en) | 1995-09-07 |
| JPH07267639A (en) | 1995-10-17 |
| BR9500734A (en) | 1995-10-24 |
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