Reaction Monitoring in Chemical Engineering with Quantitative Online NMR Spectroscopy

Transcription

1 Reaction Monitoring in Chemical Engineering with Quantitative nline MR Spectroscopy Hans Hasse 1, Sebastian Hoch 1, Erik von Harbou 1, Klaus Albert 2 1 Laboratory of, Technische Universität Kaiserslautern, Germany 2 Institute of rganic Chemistry, Eberhard-Karls Universität, Tübingen, Germany

2 MR Spectroscopy in Chemical Engineering Reaction and process monitoring and elucidation qualitative and quantitative analysis complex reacting mixtures Hyphenated MR spectroscopy non-invasive measurements no change of: temperature pressure sample composition Technical samples deuterium-free hazardous chemicals

3 MR Laboratory & LTD Laboratory of

4 Hyphenation of Reactors with MR Spectrometer Typical set-up HPLC pump split valve stirred batch reactor Lines PEEK mm ID liquid thermostated Present limits p max = 350 bar t max = 130 C Standard MR flow cell V active = 90 µl

5 Formaldehyde Important C1 building block High reactivity large variety of formaldehyde-based products use in aqueous solutions Reactions in aqueous formaldehyde solutions Formation of Methylene glycol CH 2 + H 2 HCH 2 H Formation of Poly(oxymethylene) glycols H(CH 2 ) n-1 H + HCH 2 H H(CH 2 ) n H + H 2 Similar reations with Methanol yield Hemiformals

6 Urea-Formaldehyde Resins Most common binder for wood products Used in very large amounts in wood industry Production for ~ 80 years, yet still not fully understood Reaction Pathways ph < 9 H H 8 H H H H 9 7 H 2 H H 2 H 1. 2 H H ph H + FA ph 7-8 H H H H H 2 H 2 H 2 1 H 3 3a H H H ph 3-4 H 2 H H H H 2 H 2 H H 4 15 H 16 H H H H H usw. H 1. Methylolisation 2. Condensation 3. Curing ph PLYMER

7 Laboratory of Reaction Monitoring - Hydroxymethylation of Urea H H H H H H H2 H2 water & methylene groups from hydroxymethylated ureas and formaldehyde H ppm

8 mole fraction Laboratory of Modeling Urea Hydroxymethylation Kinetics Comparison of experiment and simulation 1.00 reaction of formaldehyde + urea Sim MDU_ges Sim MMU Sim MMU-o Sim DMU Sim DMU-o HS MMU MMU-o MDU DMU DMU-o Sim MDU FA Balance Exp. (MDU~1.5*FA) Sim HS Sim free FA Sim bound FA-Units time / s

9 Hyphenation of Reactors with MR Spectrometer Typical set-up HPLC pump split valve stirred batch reactor Lines PEEK mm ID liquid thermostated Present limits p max = 350 bar t max = 130 C Standard MR flow cell V active = 90 µl Set-up for reactions with > 10 min

10 Monitoring Fast Reactions with MR Spectroscopy Using Micro-Reaction Technology eed for reduced time delay: Minimization of dead volume Relocation of reactor Micro-reaction technology Micro-mixers as reactors Coupling with flow MR spectroscopy Reactants A B

11 Coupling Micro-Mixer with nline MR Thermostated mixer below MR magnet Hastelloy mixer (max. 20 bar, ml/min) Syringe pumps (max. 500 bar, ml/min)

12 Coupling Micro-Mixer with nline MR Thermostated mixer below MR magnet Hastelloy mixer (max. 20 bar, ml/min) Syringe pumps (max. 500 bar, ml/min) peration modes: stationary flow mode ( 1 H and 13 C MR) instationary stop-flow mode ( 1 H MR)

13 Comparison of Results of Different Methods Laboratory of mole fraction / % methyl formiate 1 H-MR methanol 1 H-MR methyl formiate 1 H-MR methanol 1 H-MR methyl formiate 13 C-MR methanol 13 C-MR Mode: instationary stop flow stationary flow Test System: CH 3 H + HCH CH 3 CH + H time / s All methods give consistent results Set-up for reactions with > 1 min

14 Coupling Micro-Mixer with nline Capillary MR Preliminary set-up Installation of micro-mixer in MR probe head, next to active volume eed for very small mixer anomixer (Upchurch Scientific) flow:10 nl/min μl/min Solenoidal capillary 1 H MR probe V active = 5 μl t max = 150 C p max = 120 bar flow = µl/min Set-up for reactions with > 0.1 min

15 Coupling Micro-Mixer with nline Capillary MR Preliminary set-up Installation of micro-mixer in MR probe head, next to active volume eed for very small mixer anomixer (Upchurch Scientific) flow:10 nl/min μl/min Solenoidal capillary 1 H MR probe V active = 5 μl t max = 150 C 3-(methylamino) -propylamine (MAPA) in H 2 p max = 120 bar flow = µl/min Set-up for reactions with > 0.1 min ppm (f1)

16 Coupling Micro-Mixer with nline Capillary MR Preliminary set-up Installation of micro-mixer in MR probe head, next to active volume eed for very small mixer anomixer (Upchurch Scientific) flow:10 nl/min μl/min Solenoidal capillary 1 H MR probe V active = 5 μl t max = 150 C 3-(methylamino) -propylamine (MAPA) in H 2 p max = 120 bar flow = µl/min Set-up for reactions with > 0.1 min ppm (f1) Problem: efficient thermostatization

17 Thermostated Micro-Mixer MR Probe Head Prototype Co-operation: TU Kaiserslautern Universität Tübingen Institut für Mikromechanik Mainz (IMM) Capillary MR probe + micro-mixer Completely liquid-thermostated medium: FC 43 (Perfluorotributylamine) educt- and product lines micro-mixer MR probe Air cooling: electronics, body t max = 120 C, p max = 150 bar Reactions with τ > 0.1 min Laboratory of

18 verview ew Probe Head Top plate MR probe Dwell unit Micro-mixer Connexions 83 mm Bottom plate Electronics 35 mm

19 Probe Head Details: Mix & Dwell Micro-mixer (IMM) Material: PEEK Split & mix crawler type Flow rate: μl/min Dwell unit Material: PEEK Various line diameters available Adjustable residence time

20 Probe Head Details: MR Flow Cell Material flow cell: silica glass Solenoidal coil V active : 4 μl Thermostating liquid FC 43 flows around coil & cell Temperature measurement (in FC 43)

21 ew Probe Head: Typical 1 H MR Spectrum Laboratory of t = 25 C x MeH = 0.5 mol mol -1 x FAc = 0.5 mol mol -1

22 Post Combustion Carbon Capture (PCC) First Application of ew MR Probe Head Reactive absorption with aqueous amine solutions

23 C 2 Absorption in Aqueous Amine Solutions: Complex Reacting Systems Laboratory of MR spectrocopy for studying liquid phase reactions

24 loaded solution unloaded solution MR Monitoring C 2 + MEA + Water Dilution Experimental set-up MEA + H 2 (liq.) Laboratory of MR with new micromixer probe head C 2 (liq.) Stirred view cell C 2 + MEA + H 2 (liq.) MEA Monoethanolamine Piston pumps Pressure control Set-up fully liquid-thermostated

25 MR Monitoring C 2 + MEA + Water Dilution Stacked 1 H MR Spectra Laboratory of H CH 2 CH 2 H H MEA/MEAH + H CH 2 CH 2 MEAC - C- H Experiments: t = 25, 30, 40, 60 C Stop flow (τ 0 = 1.7 s) 60 C after τ < 200 s

26 Species mole fraction MR Monitoring C 2 +MEA+Water Dilution Experimental concentration profiles 0,08 0,07 0,06 0,05 0,04 0,03 0,02 0,01 0, t / s MEA / MEAH + MEAC - Laboratory of

27 Summary Quantitative online MR spectroscopy in chemical engineering Reaction and process monitoring and elucidation Relaible quantification of speciation of complex mixtures Coupling of MR flow probes with: conventional external reactors min 10 min external micro-mixer min 1 min Coupling of capillary MR flow probes with: internal micro-mixers min 0.1 min ew thermostated micro-mixer MR flow probe head Valuable method for chemical and pharmaceutical R&D

28 Thanks Michael Maiwald (BAM) liver Steinhof Eléonore Kibrik Andreas Scheithauer Eckhard Ströfer (BASF) Bernd Werner (IMM) Hans-Joachim Kost (IMM)