Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
MECHANO-CHEMICAL FLUORINATION
Document Type and Number:
WIPO Patent Application WO/2001/037631
Kind Code:
A2
Abstract:
A method of mechano-chemical fluorination is described that has a significantly improved yield over prior art methods of synthesis. The present invention illustrates this improved mechano-chemical Fluorination by describing the improved synthesis of Fullerene Fluorides (FF). This method overcomes reduced product yield that results from vibromill (1) material corrosion. This method also overcomes the prior fluorination and FF synthesis problems of the prior art by utilizing different fluorinating materials, adding catalysts and diluting agents to the process, varying milling times, and heating in the presence of inert gasses to improve the fluorination process.

Inventors:
NEUBERGER WOLFGANG
KALININ VICTOR
ALIKHANGAN ANDREI
Application Number:
PCT/US2000/042269
Publication Date:
May 31, 2001
Filing Date:
November 22, 2000
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CERAMOPTEC IND INC (US)
International Classes:
B01J19/02; B01J19/14; B01J19/18; C01B31/02
Foreign References:
US5731481A1998-03-24
US4814446A1989-03-21
US5382719A1995-01-17
Other References:
See also references of EP 1272276A2
Attorney, Agent or Firm:
Skutnik, Bolesh J. (Inc. 515 Shaker Road East Longmeadow, MA, US)
Download PDF:
Claims:
What is claimed is :
1. A method of mechanochemical fluorination wherein ; placing reaction materials within appropriate mechanochemical reaction equipment ; said mechanochemical reaction equipment having an appropriate special protective coating, which resists the effects of fluorine ; and introducing mechanical energy to initiate a mechanochemical reaction.
2. A method according to claim I wherein said protective coatings are chosen from the group : WC, W12C, Diamondlike Carbon films, and Chemical Vapor Deposited Ni.
3. A method according to claim 1, wherein a catalyst is added to said reaction materials/mixture prior to said mechanochemical reaction step.
4. A method according to claim 1 wherein a diluting agent is added to said reaction mixture containing materials before said mechanochemical reaction step.
5. A method according to claim 1, wherein said container is chilled/cooled during said mechanochemical step.
6. A method according to claim 1, wherein said mechanical energy to initiate said mechano chemical reaction is introduced in a pulse regime and said pulse regime preferably has a ratio of milling operation time to power off time of between 1 : 2 and 2 : 1.
7. A method according to claim 1 wherein said reaction materials are heated subsequent to said mechanochemical reaction step and said heating step reaches between 200400 °C and continues for 114 hours.
8. A method according to claim 1 wherein said heating step is done in the presence of an inert gas such as N2, Ne, He or Ar.
9. A method according to claim 8 wherein said heating step is done in presence of a fluorine containing gas mixture which has a ratio of fluorine to said inert gas between 1 : 10 and 1 : 40.
10. A method according to claim 1, wherein Fullerene Fluorides (FF) are manufactured/ synthesized by reacting various fullerene and fluorine containing materials and wherein said mechanochemical process results in a FF mixture (C6oF48, C6oF36, C6oFig, etc.).
11. A method according to claim 10 wherein ; said mechanochemical process is a vibromilling process, said fullerene and fluorine containing materials are vibromilled by means of metal balls, said metal balls and a container are fabricated with said special protective coatings which resist the effects of fluorine, and said balls are separated from said FF mixture and products of decomposition subsequent to said vibromilling step.
12. A method according to claim 10 wherein a catalyst such as NiF2, FeF2, A1F3, is added to said fullerene and fluorine containing materials before said mechanochemical step to intensify the fluorination process.
13. A method according to claim 10 wherein diluting agents such as A1203, Zr02, and Y203 are added to said fullerene and fluorine containing materials before said mechanochemical step.
14. A method according to claim 10, wherein said fluorine containing material includes at least one of the following compounds ; MnF3, CeF3, FeF3, CoF3, XeF2, CIF, TbF3, TbF4, K2PtF6 and K2NiF6.
15. A method according to claim 1 wherein said FF mixture is separated into individual substances by means of vacuum distillation for 15 hours at a temperature up to 150 °C and with vacuum of at least 107 torr.
16. A method according to 15 wherein all FF compositions are verified by means of mass spectrometry.
17. A method according to claim 1 wherein said resulting FF mixture is separated into individual substances by means of preparative mass spectrometry.
18. Catalysts for high yield, high purity mechanochemical fluorination of fullerenes composed of metallic fluorides chosen from the group : NiF2, FeF2, and AIF3.
19. Fluorine sources for highly selective high yield, high purity, mechanochemical fluorination of fullerenes selected from the group : MnF3, CeF3, FeF3, CoF3, XeF2, C1F, TbF3, TbF4, K2PtF6 and K2NiF6.
Description:
MECHANO-CHEMICAL FLUORINATION The present invention relates to mechano-chemical fluorination, specifically an improved method of fullerene fluorination.

Fullerene Fluorides (FF) are useful and can be employed in many fields. For example in the field of medicine they have been used in AIDS research. (Volpin M. E., Belavtzeva E. M., Romanova V. S.,"Self assembling of associates of amino acids and dipeptide derivatives of 60 fullerene in aqueous solution."Mendeleev Comm. 1995 129-131.) They have also been used in the synthesis of super-conductive materials and to aid in the production of nanotubes. (Haddon R. C., Hebard M. J., Nature. 350 320 (1991) ; Lijima S.

Nature, 354 56 (1991)) To produce FF in the prior art, several conventional prior art methods are used. For example, Fullerenes C6o and C70 are known to react with elemental fluorine and chlorine, as well as with XeF2, CIF3 to form fullerene halides. Fluorination of C60 results in the formation of a mixture of compounds from C6oF2 to C6oF60. C60F48 is the major component of the mixture formed upon long-term fluorination. (Gahk A. A., Tuinman A. A. Adcock J. L.

Tetraedron Lett. 34 (45), 7167-7170 (1993)) Fluorination of C60, upon exposure to UV radiation has been reported. (Cox D. M., Cameron S. D., Tuinman A. A., J. Am. Chem. Soc.

116 (3), 1115-1120 (1994)) Fullerene Fluoride C6o readily transfers into gas phase and can be identified by mass-spectrometry.

According to Halloway J. P., Hope E. J., Taylor R., J. Chem. Soc. Chem. Comm. 1991 (14), 966, fluorination of solid C60 with gaseous fluorine at 70 °C for 12 days in Ni container leads to the formation of a white substance identified as C6oF60. (Malkerova I. P., Secastianov A. S., Alikhanyan A. S., Dokl. Acad. Nauk., Chemistry (Russian). 342 (5), 630-634 (1995)) This can be identified using 19F NMR and IR spectra with fluorine upon exposure UV radiation. (Tuinman A. A., Gakh A. A., Adkoc J. L."Fluorinated Fulerenes"J. Am. Chem. Soc.

115 5885 (1993)) It is also possible to use CIF3 as the fluorinating agent. (Alikhanyn A. S., Malkerova I. P., Sevastynov D. I. et all. Zhurnal Neorgan. Khimii. (Russian) 40 (9), 1502- 1509 (1995)) These prior art methods however, are impractical and inefficient. Most techniques produce a low yield of the desired product. Another problem is that these techniques are too slow to be practical. An added problem with the production of FF is that it causes corrosion of materials and containers.

U. S. Pat. No. 5, 558, 903 describes a method to fabricate FF films that have an improved purity and adhesion to a substrate. A sublimation method is described for preparing fullerene coatings. The process is carried out in the presence of a substrate in a fluorine flow at 450-550 °C. This invention describes the use of fullerene materials as very good lubricants. The drawback to the method described is that it produces very poor yields and low purity materials.

U. S. Pat. No. 5, 382, 719 describes a method to fabricate FF with fluorinate, CF straight chain hydrocarbon from 1 to 100 carbon atoms. Using this method, however, it is impossible to fabricate precise compositions such as C6oF48, C60F36, or C60FI8.

U. S. Pat. No. 5, 510, 098 describes a related method based on the CVD synthesis of doped fullerenes (including Ni, Rb, Cs, F, etc.) in large macroscopic quantities. This synthesis is relatively inexpensive and does not require the use of solid carbon materials such as graphite. Improved hot-filament-assisted chemical deposition method is used for the simultaneous deposition of diamond and fullerene on silicon substrates and other refractory metals such as W or Ta. This process creates diamond like films located in the central part of the substrate (substrate temperature-900 °C), and fullerene soot located close to the substrate holder edge (500-700 °C). In this invention an example is given where the pressure used in this method is between 300-100 torr. Fullerene soot (5-20 mg) is collected for 5 hours.

Some drawbacks to this method however, are that the yield is only around lmg/hour and that the obtained FF compositions are varied.

Conventional vibromilling is used in the synthesis of some materials such as NH3 from environmental nitrogen (Ivanova T. P., Lipson A. G., Kutznetzov V. A. et all."Mechano- chemical synthesis of ammonia upon titanium dispersion."News from Russian Academy of Scientific. Series of Chemistry. 42 (1), 237-238 (1993)) cement clinker at 700 °C, and high temperature superconductor YBa2Cu307 (Lipson A. G., Petrov S. V., Kutnetzov"Effect of the mechano-activation of components on the physiochemical properties of super conducting Yttrium-barium ceramics"V. A. Dokl. Report's Academy of Scientific USSR. 306 (6), 1409- 1412 (1989)) Conventional vibromilling however, has limited application to the synthesis of FF. FF synthesis causes prior art containers and milling balls to corrode and crack. This destruction of vibromilling materials decreases the quality of synthesis results. The present invention, however has overcome these deficiencies in FF synthesis.

* It is an object of the present invention to provide a method of mechano-chemical fluorination that has an increased yield.

It is also an object of the present invention to provide a method of mechano-chemical fluorination that reduces or eliminates corrosion and destruction of vibromilling materials.

It is another object of the present invention to illustrate a mechano-chemical method of synthesizing Fullerene Fluorides that is commercially practical.

Briefly stated the present invention provides a method of mechano-chemical fluorination that has a significantly improved yield over prior art methods of synthesis. The present invention illustrates this improved mechano-chemical Fluorination by describing the improved synthesis of Fullerene Fluorides (FF). This present method overcomes reduced product yield that results from vibromill material corrosion. This present method also overcomes the prior Fluorination and FF synthesis problems of the prior art by utilizing different fluorinating materials, adding catalysts and diluting agents to the process, varying milling times, and heating in the presence of inert gasses to improve the fluorination process.

The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings.

Figure 1 depicts a top view of a vibromill.

Figure 2 depicts a cross sectional view of a vibromill.

Chemical reactions can be triggered by the use of mechanical forces instead of thermo chemical activation. Mechano-chemistry has been used for the non-thermal low-temperature synthesis of many inorganic and organic compounds, molecular complexes and composite materials. In particular mechano-chemistry has been applied to the synthesis of fullerene compounds. The majority of mechano-chemical processes are pulsed so that a stress field will occur and relax with the pulse cycle. The typical method for mechano-chemistry processes has been done mainly by ball milling.

Mechano-chemical activation methods used in the prior art for synthesis of various materials have only limited uses due to some essential deficiencies. The use of conventional vibromilling methods for example, are limited by corrosion and cracking of the balls and containers used in milling. Other disadvantages of prior art methods are the extended amounts of time the synthesis process takes and the typically low yield and low purity of desired product. The present invention describes an improved method of mechano-chemical synthesis as exemplified with FF production. The present invention vibromilling method uses new types of balls, containers and fluorinating materials. The milling process itself is varied in time and temperature. This method uses varied fluorinating materials, catalysts,

diluting substances, and inert gases during the heating stage. The protective coating on the containers and balls is possible through advances in coating application technology.

(Lakhotkin Yu. D., Kuz'min B. P. Praktika protivokorrozionnoi zashitu. (Russian) 1998 (1), 35-38) An advantage of the present invention method is a higher rate of fluorination.

The present invention illustrates a new mechano-chemical method of Fluorination by using Fullerene Fluorination as a commercially significant example. The present invention improves upon the prior art by utilizing improved containers and balls, which have a special protective coating. A preferred embodiment of the present invention uses a coating such as WC, W12C, diamond like coating, or Ni CVD film. In a general embodiment of the present invention, fullerenes and fluorine containing materials are mixed together with diluting materials such as A1203, ZrO2, or Y203. This mixture and specially coated balls are placed within the specially coated container. The mechanical movement of the vibromill activates the reaction between the fullerenes and the fluorine containing materials.

In a preferred embodiment, the equipment for production of fullerene fluorides includes a vibromill (Fig. 1), a furnace for thermal treatment of materials in inert gases after milling, and an installation for vacuum distillation equipment or mass-spectrometer. The balls and containers are coated with an appropriate special coating to reduce corrosion and reduce contamination of products.

The present invention applies not only new types of containers and balls, but also uses a new variety of fluorinating materials, catalysts and diluting substances. The application of different fluorides, change of frequency of milling, change in mass of balls, addition of coatings, and introduction of special catalysts, diluting agents and inert additives all lead to the synthesis of pure fluorides. This improved process is used to synthesize C6oFlg, C60F36, C6oF4gand other similar substances. Figure 1 depicts the vibromilling device for synthesis, which consists of a large container 1 (diameter 90-100 mm) and four smaller containers 2 inside larger container 1.

With reference to Figure 2 in a preferred embodiment, the method of FF production is as follows. Fullerene is placed into specially coated container 2. Specially coated balls 3 are placed inside container 2 with mixture 4 of fullerenes and fluorine containing substances (such as MnF3, CeF3, TbF3). Catalysts such as NiF2, FeF2 or A1F3 are also added to intensify the fluorination process. Raw materials are milled for 5 to 10 min. in a pulse regime. Pulse regime energy is applied by alternating on/off power supply to the equipment. In this

preferred embodiment the pulse regime has a ratio of milling operation time to power off time of between 1 : 2 and 2 : 1.

The interval between the milling operations is preferably between five and ten minutes. The milling sequence continues for a suitable amount of time depending on the chosen fluorine containing substance. The power setting for vibromilling is 40-60 W/g, and the frequency is set for 50-60 Hz. For optimal results, it is necessary to chill containers 2 during the vibromilling process. Vibromilling triggers the mechanical activation process between fullerene and fluorine containing materials. Alternatively, diluting agents such as A1203, Zr02 or Y203 are added as well to decrease the thermodynamic activity of fluorine containing reagents. Addition of these substances allows different fluorine fullerenes to be obtained that follow the formula C6oFx In this equation, the variable x is a function of fluorine activity, temperature, and the time of milling and reaction.

After milling is complete, the resulting substances are heated up to between 200-400 °C for duration of 1-10 hours. The heating process is carried out in the presence of inert gases such as N2, Ne or Ar. Alternatively the heating process is carried out in a diluted fluorine containing gas mixture of 1 part fluorine to 10-20 parts of inert gas. After the heating time is complete, balls 3 should be separated from the materials and decomposition products of fluorine containing mixture 4. The resulting mixture ofFF (C6oF4s, C6oF36, C6oFi8, etc.) is then separated into individual substances. This can be achieved by means of either mass spectrometry or vacuum distillation for 15 hours at temperatures between 150 and 350 °C and a vacuum of at least 10-7 torr. In the experiments, all FF compositions have been identified using Knudsen and Laser mass-spectrometry and Fourier transform infrared spectroscopy (FTIR).

The present invention is further illustrated by the following examples, but is not limited thereby. The following examples are distinguished from the prior by an increase in yield and end product purity.

Example 1 : C60-7g, MnF3-15g Vibromilling time-2h 40 min Conventional vibromill : diameter of container-85mm ; 7 balls with diameter 8mm Coating : Ni-CVD on container walls and balls

Heat in N2 atmosphere-lOhours ; temperature = 150 °C Distillation of mixture FF in vacuum : 10-9 torr for 15 hours Yield = 75% and purity = 98. 1% of C60F36 Example 2 C60-5g, CeF4-18g Vibromill time-2 hours 10 min ; Conventional vibromill, diameter of container-85mm ; 7 balls with diameter 8 mm Coating : WC on container walls and balls Heat in Ne for 5 hours ; temperature = 210 °C Vacuum distillation 10-9 torr Yield = 77% and purity = 98. 2% Of C6oF36 Example 3 C60-5g, TbF4-12 g Vibromilling time-2h 50 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm Coating Wl2C on container walls and balls Heat in N2-8 hours ; temperature = 210 °C Yield = 73% and purity = 98. 3% ofC6oF36 Example 4 C6o-5. 5 g, CoF3-12. 5 g Vibromilling time : lh 40 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm Coating : diamond-like coating film on container walls and balls Heat in N2-8 hours ; temperature = 210 °C Yield = 79% and purity = 98.2% of C60F36 Example 5 Vibromilling time : 2h 40 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm

Coating : Ni-CVD on container walls and balls Heat in Ar-8 hours ; temperature = 210 °C Yield = 69% and purity = 98. 4% Of C6oF36 Example 6 C60-5g ; K2PtF6-7g Vibromilling time : 2h 10 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm Coating : Ni-CVD on container walls and balls Heat in N2-8 hours ; temperature = 210 °C Yield = 70% and purity = 98. 2% Of C6oF36 Example 7 C60-7g ; Fe2F3-15g Vibromilling time : 3h 40 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm Coating : WC on container walls and balls Heat in N2-12 hours ; temperature = 210 °C Yield = 71% and purity = 98. 3% Of C6oF36 Example 8 C6o-16g ; MnF3-1. 8g Vibromilling time : I h 40 min Vibromill : diameter of container-85mm ; 7 balls with diameter 8 mm Coating : WC, DLC-film, or NI-CVD film on container walls and balls Heat in NE/F2 (1 : 10 ratio) for 10 hours ; temperature = 330 °C Yield = 72% and purity = 98. 3% Of C6oF36 Example 9 C60-lOOmg ; MnF3-700 mg ; ScF3-900 mg Milling time : 25 min Coating : Ni-CVD film on container walls and balls Heat in F2/He (1 : 8 ratio) for 40 min ; temperature = 370 °C

Yield = 80% and purity = 98. 0% Of C6oF36 Of C6oF36 Total reaction time-8 hours Example 10 C60-100mg ; K2NiF6-400 mg ; NiF2-100 mg Milling time : 35 min Heat in F2/Ne (1 : 10 ratio) for 45 min ; temperature = 375 °C Yield 75% of 98. 5% purity Of C6oF36 Total reaction time-9 hours Example 11 C60-100mg ; CoF3-800 mg ; YF3-1000 mg Milling time : 50 min Heat in FJ Ar (1 : 12 ratio) for 35 min ; temperature = 375 °C Yield 70% of 98. 1% purity Of C6oF36 Total reaction time-9 hours Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to these precise embodiments, and that changes and modifications may be effected by one skilled in the art without departing from the scope of the invention as defined in the appended claims.