Laser Chemistry in Suspensions: New Products and Unique Reaction Conditions for the Carbon-Steam Reaction

Angewandte Chemie (International Edition in English)

Volumn 36, Issue 1-2, 1997, Pages 163-166

  Chen, Huxiong ^a   McGrath, Thomas ^a   Diebold, Gerald J ^a  

^a BROWN UNIVERSITY   (United States)

Author keywords

Carbon; Hydrocarbons; Laser chemistry; Soot; Suspensions

Indexed keywords

EID: 0030788430     PISSN: 05700833     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.199701631     Document Type: Article

References (25)

1. H. C. van de Hulst Light Scattering by Small Particles, Wiley, New York, 1957.
2. M. Kerker, The Scattering of Light and Other Electromagnetic Radiation. Academic Press, New York, 1969.
3. The evolution of gas from laser-irradiated carbon black has been reported by K. J. McEwan, P. A. Madden, J. Chem. Phys. 1992, 97, 8748-8759 in conjunction with transient gratings. For work on optical limiting see also K. M. Nashold, D. P. Walter, J. Opt. Soc. Am. B 1995, 12, 1228-1237, and references therein.
4. The evolution of gas from laser-irradiated carbon black has been reported by K. J. McEwan, P. A. Madden, J. Chem. Phys. 1992, 97, 8748-8759 in conjunction with transient gratings. For work on optical limiting see also K. M. Nashold, D. P. Walter, J. Opt. Soc. Am. B 1995, 12, 1228-1237, and references therein.
5. Standard oxidative elemental analysis of the C, H, N, and O content of the carbon black was performed by National Chemical Consulting, Tenafly, NJ (USA). The precipitate was found to contain C (71.59 wt%). H (3.01 wt%),N (1.62 wt%). and O (21.23 wt%). [6]
6. Transmission electron microscopy confirmed the agglomeration of the 25 nm particles into large groups in aqueous solution (see ref. [16]). The suspensions of carbon in water were stable for several hours. Surfactants can be used to stabilize the suspensions in water to form India inks, which qualitatively act the same as the carbon black suspensions when irradiated; however, inks were not used in these experiments in order to limit extraneous sources of H or O.
7. 200. See S. H. Yang. C. L. Pettiette, J. Conceicao, O. Cheshnovsky. R. E. Smalley, Chem. Phyx. Lett. 1987. 139, 223-238; E. A, Rohlfing. D. M. Cox, A. Kaldor, J. Chem. Phys. 1984. 81, 3322-3330; D. W. Arnold. S. E. Bradford, T. N. Kitsopoulos, D. M. Neumark. J. Chem. Phys. 1991. 95.8753-8764.
8. 200. See S. H. Yang. C. L. Pettiette, J. Conceicao, O. Cheshnovsky. R. E. Smalley, Chem. Phyx. Lett. 1987. 139, 223-238; E. A, Rohlfing. D. M. Cox, A. Kaldor, J. Chem. Phys. 1984. 81, 3322-3330; D. W. Arnold. S. E. Bradford, T. N. Kitsopoulos, D. M. Neumark. J. Chem. Phys. 1991. 95.8753-8764.
9. 200. See S. H. Yang. C. L. Pettiette, J. Conceicao, O. Cheshnovsky. R. E. Smalley, Chem. Phyx. Lett. 1987. 139, 223-238; E. A, Rohlfing. D. M. Cox, A. Kaldor, J. Chem. Phys. 1984. 81, 3322-3330; D. W. Arnold. S. E. Bradford, T. N. Kitsopoulos, D. M. Neumark. J. Chem. Phys. 1991. 95.8753-8764.
10. 200. See S. H. Yang. C. L. Pettiette, J. Conceicao, O. Cheshnovsky. R. E. Smalley, Chem. Phyx. Lett. 1987. 139, 223-238; E. A, Rohlfing. D. M. Cox, A. Kaldor, J. Chem. Phys. 1984. 81, 3322-3330; D. W. Arnold. S. E. Bradford, T. N. Kitsopoulos, D. M. Neumark. J. Chem. Phys. 1991. 95.8753-8764.
11. 2 is found in the quenched, high-temperature plasma pyrolysis of coal; unlike the carbon used here, coal is rich in a variety of hydrocarbons. See N. Berkowitz. An Introduction to Coiil Technology, Academic Press, New York, 1994. Section 6.7.
12. 6 were found, with additional small peaks near the characteristic peaks for these species; however, the spectra were not consistent with either the purely or singly hydrogenated analogues of these species.
13. The ultrasensitive analysis of the graphite for hydrogen (by AMMitographic methods) was carried out by LECO Inc., Midland, MI (USA). Although the aqueous suspension of graphite powder produced gases on irradiation by the laser, the quality of the suspension was so poor that comparison of composition of the gas with that of the suspensions of carbon black, as shown in Figures 1 and 2. was judged to be inappropriate. In addition, these particles are a bit too large (1 urn diameter) to be considered within the Rayleigh limit discussed in ref. [11].
14. Particles whose radii are small compared with the wavelength of the exciting radiation (the Rayleigh limit), in the absence of any cooling mechanism, reach the same final temperature irrespective of particle diameter. The calculation of the temperature with heat diffusion is based on Equation 10.2.6 in H. S. Carslaw. J. C. Jaeger, Conduction of Heat in Solids. 2nd ed, Oxford university Press, New York. 1956. for a sphere with the same diffusivity as the surrounding material. In addition to heat conduction, several other heat loss mechanisms can be operative, including phase chunges. chemical reaction, und radiation. However, for any loss mechanism dependent on surface area, the increase in the thermal inertia of u sphere with increasing radius (but still within the RayJeigh limit) argues for a higher average surface temperature for large particles, as well.
15. 18 signal in the CO.
16. See H. X. Chen, G. J. Diebold, Science 1995, 370, 963-966. The sound waves can be strong enough to fracture the glass wall of the syringe at the concentrations and power levels used here.
17. In studies of optical limiting in carbon black suspensions, light emission is observed. See, for instance. K. Mansour, M. J. Soileau, E. W. Van Stryland. J Opt. Sot: Am. 1992. 9, 1100-1109; with regards to light emission and ionizalion, see also W. Rohcrs. H. Schroder. K. L. Kompa. R. Niessner. Z. Physxikalixche Chem. 1988, 159, 129-148.
18. In studies of optical limiting in carbon black suspensions, light emission is observed. See, for instance. K. Mansour, M. J. Soileau, E. W. Van Stryland. J Opt. Sot: Am. 1992. 9, 1100-1109; with regards to light emission and ionizalion, see also W. Rohcrs. H. Schroder. K. L. Kompa. R. Niessner. Z. Physxikalixche Chem. 1988, 159, 129-148.
19. The width of the white light pulse was found to to identical to that of the laser to within the lime resolution of the apparatus. A 1P28 photomultiplier with a risetime of 2.2 ns and an oscilloscope with a 350 MHz bandwidth were used here.
20. The results from transmission electron microscopy are somewhat at odds with those of light scattering. After 10 min of irradiation, no paniculate matter could be found by the former technique, while the latter showed particles with a hydrodynamie diameter of 100 nm. We attribute this disparity to the drying that is required to prepare a sample for electron microscopy, which may cause the formation of precipitates, Note that extraction of the particle diameters from the light scattering data presumes the existence of spherical particles only. which appears to make the agglomeration diameters somewhat larger than those determined by electron microscopy.
21. Smaller, but somewhat similar structures have been reported in the laser irradiation of soot in Humes. See R. L. Vunder Wal. M. Y. Choe. K. O. Lee. Combustion Flame 1995, 102, 200-294.
22. Absorbing solids also can undergo chemical reactions when driven to high temperatures with a laser. See S. Mohr, H. Muller-Bbuschbaum, Angew. Chem. 1995. 107. 671-677; Angew. Chem. Int. Ed. Engl. 1995, 34, 634-640.
23. Absorbing solids also can undergo chemical reactions when driven to high temperatures with a laser. See S. Mohr, H. Muller-Bbuschbaum, Angew. Chem. 1995. 107. 671-677; Angew. Chem. Int. Ed. Engl. 1995, 34, 634-640.
24. K. S. Suslick, P. Boudjouk in Ultrasound. Its Chemical, Physical and Bialogical Effects (Ed.: K. S. Suslick), VCH. New York, 1988.
25. 4. products not seen in the sonolysis on toluene [19].