"Advanced Fluids as Solvents, Separation and Reaction Media"

Transkript

1 "Advanced Fluids as Solvents, Separation and Reaction Media" Michael Türk Historie / Teilnehmer Motivation / Eigenschaften von Advanced Fluids Typische Ergebnisse Vortrag

2 Historie Treffen des Kompetenzfelds: Chemical and Thermal Process Engineering am U. a. Bildung der Arbeitsgruppe (1/5): Advanced fluids as, Koordinatoren S. Bräse & M. Türk Treffen am mit 15 Teilnehmern (12 Vorträge) Einrichtung eines Graduiertenkollegs Antrag für eine Anschubfinanzierung Bewilligung am Vorbereitung des Graduiertenkollegs Beratungsgespräch am bei der DFG Treffen mit 8 Partnern Skizze einreichen Antragsskizze am an die DFG Aufforderung zum Vollantrag am Beratungsgespräch am bei der DFG Treffen mit 9 Partnern Vollantrag Mitte / Ende Juli 2010 an die DFG 2

3 Advanced Fluids. Advanced (= tunable) Fluids: Ionische Flüssigkeiten, überkritische Fluide wie sc-co 2 (incl. gasexpanded liquids ) und sc-h 2 O Anwendungsbereiche der Advanced Fluids Synthese Trenntechnik Neue, bessere Materialien Advanced Fluids Analytik Elektrochemie Biokatalyse 3

4 Teilnehmer am interdisziplinären GRK: Dr. Silke Behrens, ITC-CPV Prof. Dr. Stefan Bräse, OC (designierter stellv. Sprecher) Prof. Dr. Willy Dörfler, AM Prof. Dr. Claus Feldmann, AOC Prof. Dr. Bettina Kraushaar-Czarnetzki, CVT Dr. Jan Paradies, OC Prof. Dr. Peter Roesky, AOC Prof. Dr. Michael Türk, TTK (designierter Sprecher) PD Dr. Andreas Unterreiner, PC 2 Post-Doc N.N. 4

5 Topics und Kooperationen Grundlagen- und prozessorientiertes GRK: Dörfler, Türk Bräse, Roesky, Feldmann, Behrens, Paradies Türk, Kraushaar- Czarnetzki Bräse, Unterreiner Türk, Kraushaar- Czarnetzki, Behrens Firmen: u.a. BASF, BTS, Evonik, IoLiTec und Merck 5

6 Motivation A) Properties of common drugs: poor water solubility (> 80%) low dissolution and absorption rate high application rates necessary (undesired side effects!) improved bioavailability due to reduced particle size is desirable B) Preparation of metallic (Pt) nanoparticles (By wet impregnation, co-precipitation or sol-gel methods) poor control of the deposition process (particle size and size distribution, metal concentration) high temperatures required large volumes of waste water Supercritical fluids (SCFs) as Solvents, Separation and Reaction Media? 6

7 Supercritical fluids SCF Nach E.U. Franck & M. Buback 7

8 Advantages of sc-co 2 allows processing at low temperatures due to low T C suitable for heat sensitive materials liquid-like density / high compressibility high diffusivity and low viscosity no surface tension can be used as solvent or anti-solvent doesn't react with many organic compounds co-solvents, such as methanol, enhance the solubility of polar solutes in CO 2 non-toxic, non-inflammable, and inexpensive solvent free product / easy to recycle 8

9 Formation of organic (nano)particles Common supercritical fluid processes are: Gas Anti-Solvent (GAS) and its numerous modifications Rapid Expansion of Supercritical Solution (RESS) 9

10 SCF-processes GAS-process: In GAS, the material to be processed is dissolved in a liquid organic solvent (MeOH). Decreasing the solvent power of a liquid solvent by saturating it with supercritical anti-solvent (CO 2 ). Particle size depends strongly on growth rate (controlled by the rate of pressurisation), by the concentration in the liquid and the phase behaviour (CO 2 /MeOH). Particles can be dried with CO 2. b) RESS a) GAS organic solvent sc-solution anti-solvent 10

11 SCF-processes RESS-process: In RESS, the material to be processed is dissolved at high pressure ( 30 MPa) in the supercritical fluid (CO 2 ). The supercritical solution is then rapidly depressurized through a nozzle into an expansion unit (0.1 MPa & 298 K). Extremely rapid nucleation of the product leads to a highly dispersed material. Very fine (< 1 µm) and solvent free particles are obtained. b) RESS a) GAS organic solvent sc-solution anti-solvent 11

12 Formation of organic (nano)particles Common supercritical fluid processes are: Gas Anti-Solvent (GAS) and its numerous modifications Rapid Expansion of Supercritical Solution (RESS) fast process Advantages: reduce the organic solvent consumption suitable for heat sensitive materials narrow particle size distribution ability to control particle characteristics (size & morphology) 12

13 Results from RESS-experiments N O NH2 CH3 OH H3C 13 O O

14 Freisetzungsapparatur # Frage: Wie schnell wird der Wirkstoff freigesetzt? G H B C F I A E D A: Thermostat E: Filterkopf mit 0.2 µm Millipore Filter B: ph-gerät F/G: Lösungsmittelkreislauf C: Temperatur H: HPLC-Pumpe D: Probenahme I: Probeentnahme # DA S. Müller

15 Dissolution behaviour # 100 dissolved amount (%) RESS Original 62,3 % Griseofulvin ph = m 2 /g t (min) 0.6 m 2 /g primary particles in the range of ca. 50 nm increased surface area (10 20 x higher) improved dissolution # and absorption behaviour # Türk et al.; JSCF, 22 (2002) 75 15

16 Dissolution behaviour Comparison: Original RESS - product Strong influence of both: ph value and particle size 16

17 Basics of the SFRD- process Supercritical Fluid Reactive Deposition Interdisciplinary project Particle Formation by SFRD Türk Engineering Precursor Synthesis Bräse & Roesky Chemistry metallic nanoparticles Characterization (TEM, EDX) Gerthsen & Schneider Physics catalytic performance Kraushaar-Czarnetzki Engineering biological response Marko (now Vienna) Chemistry 17

18 Basics of the SFRD- process Supercritical Fluid Reactive Deposition 298 K, 0.1 MPa pressure- / temperature- increase 353 K, 15.5 MPa a) chemical reduction 353 K, 15.5 MPa Me-complex + CO 2 + H 2 substrate Impregnation / Adsorption substrate b) thermal reduction substrate c) chemical reduction pressure- / temperature- decrease pressure- / temperature- decrease substrate T 298 K, 0.1 MPa + H 2 d) thermal reduction substrate 298 K, 0.1 MPa substrate T 298 K, 0.1 MPa substrate A) β-cyclodextrin; (C 6 H 10 O 5 ) 7 B) MCM-41 (porous SiO 2 ) Me-complex: (COD)PtMe 2 Au(C 6 F 5 )PPh 3 C) Al 2 O 3 foams 18

19 Supercritical Fluid Reactive Deposition # 1) Adsorption of the complex (COD)PtMe 2 substrate + H 2 + SCF substrate - SCF 2) Reduction of the complex Pt 3 nm (COD)PtMe H 2 + Pt ±0 + 2CH 4 # S. Bräse, T. Muller, D. Gerthsen, B. Kraushaar-Czarnetzki, R. Schneider 19

20 Results from SFRD experiments 1 a) to d) reduction in sc-co 2 on β-cd, e) reduction at atmospheric pressure on β-cd, and f) reduction in sc-co 2 on MCM (TEM from D. Gerthsen & R. Schneider) 20

21 Results from SFRD experiments 2 3,1 nm X 50 = 12 nm nm X 50 = 7,7 nm X 50 = 155 nm 100 nm Particle size and size distribution can be (easily) controlled 100 nm 21

22 Results from SFRD experiments 3 Compared to the conventional (aqueous) impregnation, deposition of Pt by SFRD yields to a higher catalytic activity as the sample with impregnated Pt. 22

23 RESS: Summary particles as small as 70 nm can be produced particles show improved dissolution behaviour agglomeration of the particles can be impeded by using polymers SFRD: enables the formation of particles with defined properties particles smaller than 10 nm can be produced Pt-catalysts show an improved activity Supercritical CO 2 is a novel particle formation media which enables the formation of new products with improved properties. 23

24 Thanks to Sponsoren: DFG: Tu 93 / 2-1, -2, -3; Tu 93 / 4-1; Tu 93 / 5-1, -2, -3, -4; Tu 93 / 6-1, -2; Tu 93 / 7-1, -2, -3 Landesstiftung Baden-Württemberg: Az /1 KIT- Kompetenzbereich: Systeme und Prozesse 24

25 Danke für Ihre Aufmerksamkeit! 25