Facile fabrication of ZSM-5 zeolite catalyst with high durability to coke formation during catalytic cracking of paraffins

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1 Supporting Information Facile fabrication of ZSM-5 zeolite catalyst with high durability to coke formation during catalytic cracking of paraffins Satoshi Inagaki, a, Shoma Shinoda, a Yoshihiro Kaneko, a Kazuyoshi Takechi, a Raita Komatsu, a Yasuyuki Tsuboi, a Hiroshi Yamazaki, b Junko N. Kondo, b and Yoshihiro Kubota a, a. Division of Materials Science and Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama , Japan. b. Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama , Japan. Corresponding Author sinagaki@ynu.ac.jp (S. I.), kubota@ynu.ac.jp (Y. K.) Experimental Preparation of ZSM-5 catalysts OSDA-free ZSM-5 zeolite was hydrothermally synthesized as follows: fumed silica (Cab-O-Sil M5, Cabot), sodium aluminate (NaAlO 2, Kanto Chemical), sodium hydroxide (NaOH, Kanto Chemical) and distilled water were mixed in a 150 ml Teflon cup. The molar composition of a parent mixture prepared in this study was 1.0 SiO Al 2 O NaOH 30 H 2 O. The hydrothermal crystallization was carried out at 170 ºC for 4 days under rotation at 20 rpm. The product solid was recovered by filtration, washed thoroughly with distilled water and dried at 80 ºC in an air oven. The parent OSDA-free ZSM-5 was treated with aqueous NH 4 NO 3 solution (zeolite: NH 4 NO 3 : H 2 O = 1 g: 2 g: 50 g) at 80 ºC for 24 h twice to obtain NH + 4 -form ZSM-5. The NH + 4 -ZSM-5 was calcined at 550 ºC for 6 h again to give H + -form (denoted parent H + -ZSM-5 OSDAF ). The parent H + -ZSM-5 OSDAF was used as a catalyst in the cracking of cumene, 1,3,5-triisopropylbenzene (TIPB) or hexane. TPA + -assisted ZSM-5 was hydrothermally synthesized as follows: tetraethoxysilane (Si(OEt) 4, Kanto Chemical), aluminum nitrate (Al(NO 3 ) 3 9H 2 O, Kanto Chemical), sodium hydroxide, tetrapropylammoium hydroxide (TPAOH, 10wt% aqueous solution, Aldrich) and distilled water was mixed in a 200 ml Teflon beaker. The molar composition of a parent mixture prepared in this study was 1.0 SiO Al 2 O NaOH 0.25 TPAOH 8.3 H 2 O. The mixture was heated at 80 ºC for 6 h to remove ethanol formed by the hydrolysis of Si(OEt) 4. The hydrothermal crystallization was carried out at 170 ºC for 1 day under rotation at 20 rpm. The product solid was recovered by centrifuging at 3000 rpm for several times and dried at 80 ºC in an air oven. The removal of TPA + in as-synthesized ZSM-5 was carried out by calcination at 550 ºC for 10 h.

2 The dealumination of parent OSDA-free ZSM-5 or TPA + -assisted, calcined ZSM-5 was carried out by treating with 0.1, 1.0, 2.0 or 6.0 M HNO 3 solution (30 ml/g-sample) in a 23-mL Teflon-lined stainless-steal autoclave at 160 ºC for 24 h under the rotation at 20 rpm. The dealuminated OSDA-free ZSM-5 treated with 6.0 M HNO 3 (denoted deal(6.0)-zsm-5) was employed in the catalytic reaction. Characterization Zeolites obtained were checked concerning their crystallinity and phase purity by X-ray powder diffraction (XRD) on an Ultima-IV (Rigaku) using CuK radiation at 40 kv and 20 ma. The contents of Al in zeolites were measured by using inductively coupled plasma atomic emission spectrometer (ICP-AES, ICPE-9000, Shimadzu). The solid-state 27 Al magic angle spinning nuclear magnetic resonance (MAS NMR) measurement was performed on an AVANCEIII-600 (600 MHz ( 1 H), Bruker). The probe with 4 mm in diameter was rotated at 13 khz during the measurement. The 27 Al MAS NMR spectra of ZSM-5 samples were recorded at 0.5 s of the contact time for 1024 times. The number of acid sites was measured by using the temperature-programmed desorption (TPD) of ammonia on a BELCAT-B (Japan Bel Inc.). The ZSM-5 zeolite was preheated at 500 ºC, cooled at 150 ºC and treated with diluted NH 3 gas for several minutes prior to the measurement. The amount of desorbed NH 3 at a ramping rate of 10 ºC min -1 was monitored by using a thermal conductive detector (TCD). The number of acid sites was determined from the area of h-peak in their profiles. IR observation was carried out on a JASCO FT/IR-4100 spectrometer equipped with an MCT detector. The self-supporting disk (20 mg, 20 mm in diameter) of the sample was placed in an IR cell attached to a conventional close gas-circulation system. The sample disk was pretreated by evacuation at 773 K for 1 h. CO and collidine (2,4,6-trimethylpyridine) were introduced into the cell at 153 and 298 K, respectively. S1 The BET surface area and micropore volume of ZSM-5 were evaluated from a nitrogen adsorption-desorption isotherm measured on an Autosorb-1-MP (Quantachrome Instruments). The ZSM-5 zeolites were heated in vacuo (ca. 0.1 mmhg) at 400 ºC for more than 12 h prior to the measurement. The morphologies of zeolite samples were observed by field emission scanning electron microscopy (FE-SEM) on a JSM-7001F (JEOL). Reaction procedures The cracking of TIPB or cumene was performed under atmospheric pressure in a pulse-type quartz-tube microreactor with 4 mm of inner diameter. The illustrations of reactor setups are shown in Fig. S3. Prior to running the reaction, 20 mg of catalyst powder was packed in a

3 fixed-bed of the reactor, and preheated at 400 ºC for 1 h in a stream of helium. The reaction was performed at 300 ºC in a stream of helium (30 cm 3 (N.T.P.) min -1 ). TIPB (0.6 μl) or cumene (0.8 μl) was injected by using a syringe at each pulse. The reactants and products were analyzed by using GC-8A (Shimadzu) with a TCD. In the case of TIPB cracking, a column (i.d., 3 mm; length, 6 m) packed with silicone OV-1 (2 %) (GL Science) was used. In the case of cumene cracking, a column (i.d., 3 mm; length, 3 m) packed with Bentone 34 (5%) + DIDP (5%) (GL Science) was used. The cracking of hexane was performed at atmospheric pressure in a quartz-tube microreactor with an 8 mm inner diameter. Before the reaction, 100 mg of ZSM-5 catalyst was packed in a fixed bed of the reactor and heated at 650 ºC for 1 h in a stream of argon. Maintaining the temperature at 650 ºC, hexane, of which the partial pressure was 5 kpa, was fed with argon. The reactants and products were analyzed using a gas chromatograph (GC-14B; Shimadzu) equipped with a flame ionization detector. [S1] J. N. Kondo, R. Nishitani, E. Yoda, T. Yokoi, T. Tatsumi and K. Domen, A comparative IR characterization of acidic sites on HY zeolite, silica-alumina and -alumina using pyridine and CO probes, Phys. Chem. Chem. Phys., 12, (2010). sample Table S1 Dealumination of OSDA-free and TPA + -assisted ZSM-5 Si/Al molar ratio d before acid-treatment e Si/Al molar ratio d after acid-treatment e degree of dealumination /% OSDA-free ZSM-5 a,c TPA + -assisted ZSM-5 b,c a. Starting gel composition: 1.0SiO Al(OH) NaOH-30H 2 O. Crystallized at 170 ºC for 4 d. b. Starting gel composition: 1.0SiO Al(OH) TPAOH-30H 2 O. Crystallized at 170 ºC for 4 d. c. Particle size was μm in each case. d. Acid-treatment was carried out using 6.0 M HNO 3 in 23 ml autoclave at 160 ºC for 24 h. e. Si/Al molar ratio of ZSM-5 was determined by means of ICP-AES.

4 Figure captions Figure S1 Powder XRD patterns of parent OSDA-free ZSM-5, deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. Figure S2 27 Al MAS NMR spectra of parent OSDA-free ZSM-5 (NH + 4 -form), deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. The asterisk symbol means spinning side band at 13 khz of rotation speed. Figure S3 Illustrations of setups of pulse-type reactors for (A) TIPB cracking, and (B) cumene cracking. Figure S4 NH 3 -TPD profiles of parent H + -ZSM-5 (generated in situ from NH + 4 -form), deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. Figure S5 IR spectra of CO adsorbed on parent H + -ZSM-5 OSDAF with introduction pressure at 5, 10 and (c)15 Pa at 153 K. Spectra were obtained by subtraction of background spectra from those measured after CO adsorption. Figure S6 IR spectra of parent H + -ZSM-5 OSDAF before and after saturation adsorption of collidine at 298 K after evacuation. (c) is a background-subtracted spectrum of from. Figure S7 Hexane conversion and product yield (mol%) for hexane cracking over zeolite catalysts at 650ºC. The catalysts are parent H + -ZSM-5 OSDAF (Si/Al = 16.4) and deal(6.0)-zsm-5 (Si/Al = 22.6). W/F = 19.8 g-cat. h mol -1, and partial pressure of hexane = 5 kpa. BTX means the mixture of benzene, toluene and xylenes. Figure S8 Nitrogen adsorption-desorption isotherms of parent H + -ZSM-5 OSDAF, deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. The isotherms for, (c), (d) and (e) were offset vertically by 200, 400, 600 and 800 cm 3 (S.T.P.) g -1, respectively. Open and closed symbols mean adsorption and desorption branches, respectively. Figure S9 Typical FE-SEM images of parent OSDA-free Na + -ZSM-5, parent OSDA-free NH 4 + -ZSM-5, (c) deal(0.1)-zsm-5, (d) deal(1.0)-zsm-5, (e) deal(2.0)-zsm-5 and (f) deal(6.0)-zsm-5.

5 (e) (d) Relative intensity / a.u. (c) theta (CuKα) / degree Figure S1 Powder XRD patterns of parent OSDA-free ZSM-5, deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5.

6 Supporting Information Tetrahedral Al Octahedral Al (e) Si/Al = 19.8 (ICP) (d) Si/Al = 22.8 (ICP) (c) Si/Al = 20.8 (ICP) Si/Al = 16.1 (ICP) Si/Al = 15.4 (ICP) Chemical shift from Al(NO 3 ) 3 Figure S2 27 Al MAS NMR spectra of parent OSDA-free ZSM-5 (NH + 4 -form), deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. The asterisk symbol means spinning side band at 13 khz of rotation speed.

7 Supporting Information (A) (B) Figure S3 Illustrations of setups of pulse-type reactors for (A) TIPB cracking and (B) cumene cracking.

8 Supporting Information (e) (d) Amount of desorbed NH3 / a.u. (c) Temperature / ºC Figure S4 NH 3 -TPD profiles of parent H + -ZSM-5 (generated in situ from NH + 4 -form), deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5.

9 (c) (c) Abs Abs Wavenumber / cm 1 Figure S5 IR spectra of CO adsorbed on parent H + -ZSM-5 OSDAF with introduction pressure at 5, 10 amd 15 Pa at 153 K. Spectra were obtained by subtraction of background spectra from those measured after CO adsorption.

10 (c) (c) Abs Abs Wavenumber / cm 1 Figure S6 IR spectra of parent H + -ZSM-5 OSDAF before and after saturation adsorption of collidine at 298 K after evacuation. (c) is a background-subtracted spectrum of from.

11 conversion BTX BTX Product distribution (mol%) Hexane conversion (%) C5 isomers (paraffin + olefin) C5+C5= C4 isomers (paraffin + olefin) C4+C4= propane C3 propylene C3= ethane C ethylene C2= methane C1 Time on stream / min Figure S7 Hexane conversion and product yield (mol%) for hexane cracking over zeolite catalysts at 650ºC. The catalysts are parent H + -ZSM-5 OSDAF (Si/Al = 16.4) and deal(6.0)-zsm-5 (Si/Al = 22.6). W/F = 19.8 g-cat. h mol -1, and partial pressure of hexane = 5 kpa. BTX means the mixture of benzene, toluene and xylenes.

12 Supporting Information 1000 (e) Volume of adosrbed nitrogen / cm 3 (S.T.P.) g (d) (c) Relative pressure, P/P 0 Figure S8 Nitrogen adsorption-desorption isotherms of parent H + -ZSM-5 OSDAF, deal(0.1)-zsm-5, (c) deal(1.0)-zsm-5, (d) deal(2.0)-zsm-5 and (e) deal(6.0)-zsm-5. The isotherms for, (c), (d) and (e) were offset vertically by 200, 400, 600 and 800 cm 3 (S.T.P.) g -1, respectively. Open and closed symbols mean adsorption and desorption branches, respectively.

13 Supporting Information parent (NH4+-form) parent (Na+-form) 100 nm 100 nm (c) 0.1 M HNO3 (d) 1.0 M HNO3 100 nm (e) 2.0 M HNO3 100 nm (f) 6.0 M HNO3 100 nm 100 nm Figure S9 Typical FE-SEM images of parent OSDA-free Na+-ZSM-5, parent OSDA-free NH4+-ZSM-5, (c) deal(0.1)-zsm-5, (d) deal(1.0)-zsm-5, (e) deal(2.0)-zsm-5 and (f) deal(6.0)-zsm-5.

One-pass Selective Conversion of Syngas to para-xylene

Electronic Supplementary Material (ESI) for Chemical Science. This journal is The Royal Society of Chemistry 2017 Supporting Information One-pass Selective Conversion of Syngas to para-xylene Peipei Zhang,