Superacid-Promoted Synthesis of Highly Porous Hypercrosslinked Polycarbazoles for Efficient CO 2 Capture

Transcription

1 Electronic Supplementary Material (ESI) for ChemComm. This journal is The Royal Society of Chemistry 2017 [Supporting Information] Superacid-Promoted Synthesis of Highly Porous Hypercrosslinked Polycarbazoles for Efficient CO 2 Capture Xiang Zhu,*, Shunmin Ding, Carter W. Abney, Katie L. Browning, Robert L. Sacci, Gabriel M. Veith, Chengcheng Tian*, and Sheng Dai*,, Department of Chemistry, The University of Tennessee, Knoxville, Tennessee , United States Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States *Corresponding authors: xiang@utk.edu (zhuxiang.ecust@gmail.com); Tianchengcheng.ecust@gmail.com; dais@ornl.gov

2 1. Experimental Section 1.1 Preparation of HC-PCzs Solvents, reagents and chemicals were purchased form Aldrich, Acros and TCI America. All were used without any purification. Building block M5 and M6 were prepared following the reference 1. Superacid-catalyzed synthesis of HC-PCz-1: To a solution of carbazole (M1, 234 mg) and formaldehyde dimethyl acetal (FDA, 0.11 ml) in 1, 2-dichloroethane (DCE, 5 ml), 1.0 ml CF 3 SO 3 H was slowly added (Gas protection is not required). The mixture was then kept stirring for 10 mins under room temperature and then transferred to a flat glass dish for the evaporation of DCE (The temperature of the hot plate was set to 100 C). The resultant solid was then thoroughly washed with diluted NaOH and H 2 O to remove the acid catalyst. Finally, the product was dried at 120 C under vacuum to give 218 mg HC-PCz-8. The yield is ca. 80 % and the majority of the loss is caused by the transfer process. Synthesis of HC-PCz-8: Following the same strategy, to a solution of carbazolic moiety M8 (148 mg) and FDA (0.16 ml) in DCE (5 ml), 1.0 ml CF 3 SO 3 H was slowly added. The mixture was then kept stirring for 10 mins under room temperature and then transferred to a flat glass dish for the evaporation of DCE (The temperature of the hot plate was set to 100 C). The resultant brown solid was then thoroughly washed with diluted NaOH and H 2 O to remove the impurity. Finally, the product was dried at 120 C under vacuum to give 155 mg HC-PCz-8. The yield is ca. 94%. HC-PCz-2 to HC-PCz-7, HCP-PBF and HCP-PBT were prepared using the same technique, respectively. 1.2 Characterization

3 The powder X-ray diffraction (XRD) data were recorded with a PANalytical Empyrean diffractometer, operated at 45 kv and 40 ma (scanning step: 0.02 per step). The diffraction patterns were recorded in the range of The N 2 adsorption and desorption isotherms were measured at 77 K under a Gemini 2360 surface area analyzer. 13 C solid-state NMR was performed using a Solid State Varian INOVA 400 MHz. 1 H NMR spectra were recorded on a Varian Mercury 300 MHz NMR spectrometer. X-ray photoelectron spectroscopy (XPS) data were collected using a PHI 3056 spectrometer with an Al anode source operated at 15 KV and an applied power of 350 W with samples mounted on indium foil. Small signals of In were unavoidable due to the samples adhesion to the In foil. TGA curves were collected by a TA Q50 thermogravimetric analyzer under N 2 (100 ml/min) with a ramping rate of 10 o C/min. 1.3 CO 2 /N 2 Uptake The CO 2 /N 2 adsorption-desorption isotherms of HC-PCz-8 at 273 and 298 K were recorded using an Autosorb-1-C Quantachrome analyzer. Prior to each adsorption experiment, the samples were degassed at 120 C for 12 h. 1.4 Heat of CO 2 Adsorption Calculation The isosteric heat of adsorption values were calculated using the Clausius-Clapeyron equation: P 1 ln H P 2 ads T2 T1 R T T 1 2 where P i is pressure for isotherm i, T i is temperature for isotherm i, R is J K -1 mol -1 ; which was used to calculate isosteric heat of adsorption ( H ads ) of a gas as a function of the quantity of gas adsorbed. Pressure as a function of the amount of CO 2 adsorbed was determined by the Toth

4 model for the isotherms. Q 1 t B P m 1 Q 1 1 B P t where Q=moles adsorbed, Q m =moles adsorbed at saturation, P=pressure; B and t=constants; which can be used to calculate the pressure P. 1.5 The Ideal Adsorption Solution Theory (IAST) calculations The pure component isotherms of CO 2 measured at 273 and 298 K were fitted with the single-site Langmuir model: q i = qi, sat b p i i 1+ b p i i Where, b i is is parameter in the pure component Langmuir isotherm (Pa -1 ), p i is bulk gas phase pressure of species i (Pa), p t is total bulk gas phase pressure of mixture (Pa), q i is molar loading of species i (mol kg -1 ), q i,sat is saturation capacity of species i (mol kg -1 ). Pure-component isotherm fitting parameters were then used for calculating Ideal Adsorbed Solution Theory (IAST) binary-gas adsorption selectivities, S ads, defined as: S ads = q1 / q2 p / p 1 2 The IAST calculations were carried out for binary mixture containing 15% CO 2 and 85% N 2, which is typical of flue gases.

5 2. Figures Figure S1. Nitrogen adsorption-desorption isotherms of HC-PCzs recorded at 77 K. Figure S2. TGA results of HC-PCz-1 and HC-PCz-8 (measured under N 2 ).

6 Figure S3. 13 C ssnmr spectra of HC-PCz-1. Figure S4. XRD patterns of HC-PCz-1 and HC-PCz-8, respectively. Figure S5. SEM images of HC-PCz-1 (a) and HC-PCz-8 (b).

7 Figure S6. Pore size distribution of HC-PCz-8 using non-local density functional theory modeling based on the CO 2 uptake curves at 273 K. Figure S7. C1s XPS spectra of HC-PCz-8. Figure S8. The isosteric heat of adsorption for HC-PCz-8.

8 Figure S9. The selectivity of HC-PCz-8 for CO 2 over N 2 isotherms obtained from the initial slope method at 273 K (a) and 297 K (b), respectively. Figure S10. The IAST selectivity of HC-PCz-8 for CO 2 over N 2.

9 Figure S11. Nitrogen adsorption-desorption isotherms of HC-PBF and HC-PBT recorded at 77 K, respectively. Figure S C ssnmr spectra of HC-PBF and HC-PBT.

10 Table S1. Summary of surface area, CO 2 uptake, and selectivity (CO 2 /N 2 ) at 273 K and 298 K in selected POPs. Adsorbents BET surface area (m 2 /g) CO 2 uptake (mmol/g) 273 K 298 K Selectivity by initial slope method HC-PCz This work P-PCz P-PCz CPOP (291 K) 25 3 TSP CPOP Cz-POP (290 K) 23 6 HAT-CTF- 450/ (297 K) 126 (297 K)/ 110 (297 K, IAST) PPN-6- SO 3 Li (295 K) 414 (IAST) 8 PPN-6- CH 2 DEAT (295 K) 415 (IAST) 9 PPN-6- SO 3 NH (295 K) FCTF (IAST) 11 bipy- CTF (298 K) 12 Py ALP BILP TBILP (298 K) 16 PPF (295 K) TB-MOP (298 K) 18 Ref 7

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