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1 Electronic Supplementary Material (ESI) for Green Chemistry. This journal is The Royal Society of Chemistry Electronic Supplementary Information Depolymerization of poly-(bisphenol A carbonate) under mild conditions by solvent-free alcoholysis catalyzed by 1,8-diazabicyclo[5..0]undec-7- ene as a recyclable organocatalyst: a route to chemical recycling of waste polycarbonate Eugenio Quaranta,* Damiano Sgherza, Giuseppe Tartaro Dipartimento di Chimica, Università degli Studi Aldo Moro di Bari, Campus Universitario, Via E. rabona,, 70126, Bari, Italy. eugenio.quaranta@uniba.it. Phone: Contents ATR-FT-IR spectrum of unreacted polycarbonate 2 Work-up of the reaction mixture: extraction with diethyl ether/h 2 3 Work-up of the reaction mixture: washing with diethyl ether 5 Work-up of the reaction mixture: isolation of pure BPA and -CP 9 Mass spectrum of 1a and 2a 11 Comparison of 1 H and 13 C NMR spectra of DBU, DBU. HCl, and the BPA-DBU adduct in CD 3 D and DMS-d 6 12 Mass spectrum of 1b and 2b 1

2 2 ATR-FT-IR spectrum of unreacted polycarbonate Fig. S1. ATR-FT-IR spectrum: (red) unreacted PC recovered at the end of the catalytic run; (bleu) commercial polycarbonate. ν C= : 1770 cm -1.

3 3 Work-up of the reaction mixture: extraction with diethyl ether/h 2 After the complete conversion of the polymer, the reaction mixture was distilled at room temperature in vacuum.the residue of distillation was purified from DBU by extraction with diethyl ether/h 2. The organic phase was dried on MgS, filtered and evaporated in vacuum to give a DBU-free residue containing BPA and -cumylphenol (Fig. S2). The aqueous phase was evaporated in vacuum under gentle warming to afford a colorless oil. The GCMS analysis of the oily residue is shown in Fig. S3. H BPA H 2 3 2' 3' 1 1' ' H -cumylphenol (-CP) Fig. S2. 1 H NMR (500 MHz, CD 3 D) spectrum of the BPA/-CP mixture isolated after removal of DBU by extraction with diethyl ether/h 2. The signals due to BPA are found at 1.56 (s, ), 6.65 (dm, H3) e 7.01 ppm (dm, H2), while resonances assigned to -CP can be located at 1.60 (s, ) and in the range ppm (Ph). The spectrum does not contain signals due to DBU.

4 a c b a b c Fig. S3. GC-MS analysis of the oily residue obtained from the aqueous layer after evaporation in vacuum of H 2. (a) DBU; (b) 1-(3-aminopropyl)azepan-2-one (m/z = 170; hydrolysis product of DBU); (c) BPA.

5 5 Work-up of the reaction mixture: washing with diethyl ether After the complete conversion of the polymer, the reaction mixture was distilled at room temperature in vacuum. The residue of distillation was purified from DBU by washing it with diethyl ether (20 ml). The resulting suspension was filtered and the ethereal phase was evaporated in vacuum to give a DBU-free residue (Fig. S and S5) containing BPA and -CP. The solid insoluble in ether was dried in vacuum and characterized spectroscopically as a BPA-DBU adduct (Fig. S6-S). b a Fig. S. GC analysis of the isolated BPA/-CP mixture: (a) -CP; (b) BPA. H BPA H 2 3 2' 3' 1 1' ' H -cumylphenol (-CP) Fig. S5. 1 H NMR (500 MHz, DMS-d 6 ) spectrum of the BPA/-CP mixture. The resonances of BPA are found at 1.51 (s, ), 6.62 (dm, H3) e 6.96 ppm (dm, H2), while signals assigned to -CP can be located at 1.57 (s, ) and in the range ppm (Ph). The triplet at 1.1 ppm and the partially masked quartet at 3. ppm are due to residual amounts of diethyl ether. The spectrum does not contain signals due to DBU.

6 6 50 %T , , , ,69 228, , ,65 163,35 16, , ,1 1323,17 127,9 1228,66 117,65 11,35 80,1 12,63 831,32 553, , , , ,02 22, ,72 36, /cm Fig. S6. FT-IR (nujol) spectrum of the adduct BPA-DBU: 3267 (v br), 163 (ms), 16 (m), 1593 (m), 1506, 1323, 127, 1228, 1175, 11, 80, 12, 831, 761, 723 cm -1. H BPA H N N DBU 9 BPA-DBU adduct; solvent DMS-d diethyl ether diethyl ether Fig. S7. 1 H NMR (00 MHz, DMS-d 6 ) spectrum of the adduct BPA-DBU: the resonances of BPA are located at δ 1.51(), 6.60 (dm, 8.6 Hz, H3) and 6.95 (dm, 8.5 Hz, H2) ppm, while the signals of DBU are found at δ (H3, H, H5), 1.70 (quint, 6 Hz, H), 2.3 (m, H6), 3. (t, H9), ppm (H2 e H11). The H protons of BPA give a very broad poorly evident signal at around 8 ppm. The signals near 1.1 and 3. ppm are due to residual amounts of diethyl ether

7 7 BPA-DBU adduct; solvent DMS-d Fig. S8. 13 C NMR (0 MHz, DMS-d 6 ) spectrum of the adduct BPA-DBU: the resonances of BPA are located at δ (), 0.83 (C 2 ), (C3), (C2),.60 (C1), ppm (C), while the signals of DBU are found at δ (C), 25.2, 27.59, 28.8 (C3, C, C5), 3.98 (C6), 1.99 (C9), 7.53, (C2 and C11), ppm (C7) Fig. S9. 1 H NMR (500 MHz, CD 3 D) spectrum of the adduct BPA-DBU: the resonances of BPA are located at δ 1.55 (), 6.62 (dm, 8.8 Hz, H3) e 6.98 (dm, 8.3 Hz, H2) ppm, while the signals of DBU fall at δ (H3, H, H5), 2.00 (quint, 5.9 Hz, H), 2.63 (m, H6), 3.31 (H9), 3.50 (t, 6 Hz, H11), 3.56 ppm (m, H2).

8 Fig. S. 13 C NMR (500 MHz, CD 3 D) spectrum of the adduct BPA-DBU: the resonances of BPA are located at δ (), 2.38 (C 2 ), (C3), (C2), (C1), ppm (C), while the signals of DBU are observed at δ (C), 25.03, 27.57, (C3-C5), (C6), 39.6 (C9), 9.5, (C2 and C11), ppm (C7).

9 9 Work-up of the reaction mixture: isolation of pure BPA and -CP BPA (Fig. S11 and S12) and -CP (Fig. S13 and S1) can be isolated as a pure compounds by fractionating the residue of distillation on a silica gel column, using, as eluent, petroleum ether/ethyl acetate 6:1 (v/v) until elution of -cumylphenol and, afterwords, petroleum ether/ethyl acetate 2:1 (v/v). H (BPA) H Fig. S11. 1 H NMR (00 MHz, DMS-d 6 ) spectrum of BPA isolated by chromatography. 1.51(), 6.62 (dm, 8.8 Hz, H3), 6.96 (dm, 8.8 Hz, H2), 9.11 ppm (s, H) , Fig. S C NMR (0 MHz, DMS-d 6 ) spectrum of BPA isolated by chromatography. = 30.8 (), 0.87 (C 2 ), 11.9 (C3), (C2),.99 (C1), ppm (C).

10 2 3 2' 3' 1 H 1' ' -cumylphenol (-CP) Fig. S13. 1 H NMR (500 MHz, CDCl 3 ) spectrum of -CP isolated by chromatography: δ 1.66 (s, ), 5.30 (s, H), 6.73 (dm, H3), 7. (dm, H2), 7.17 (m, H ), ppm (m, H2 and H3 ) Fig. S1. 13 C NMR (0 MHz, DMS-d 6 ) spectrum of -CP isolated by chromatography: δ = (), 1.63 (C 2 ), (C2), (C ), (C2 ), and (C3 and C3 ),.1 (C), (C1 ), ppm (C1).

11 11 Mass spectrum of 1a and 2a C C (1a) 1a Fig. S15. Mass spectrum of 1a. H C (2a) 2a Fig. S16. Mass spectrum of 2a.

12 12 Comparison of 1 H and 13 C NMR spectra of DBU, DBU. HCl, and the BPA-DBU adduct in CD 3 D and DMS-d 6 a b c Fig. S17. 1 H NMR (DMS-d 6 ) of (a) DBU: δ (m, H3, H, H5), 1.63 (quint, H), 2.23 (m, H6), 3.05 (t), (m) ppm; (b) BPA-DBU adduct: the resonances of BPA are located at δ 1.51(), 6.60 (dm, 8.6 Hz, H3) and 6.95 (dm, 8.5 Hz, H2) ppm, while the signals of DBU are found at δ (H3, H, H5), 1.70 (quint, 6 Hz, H), 2.3 (m, H6), 3. (t, H9), ppm (H2 e H11). The signals near 1.1 and 3. ppm are due to residual amounts of diethyl ether; (c) DBU. HCl: δ 1.58 and 1.6 (H3, H, H5), 1.88 (quint, 5.9 Hz, H), 2.7 (m, H6), 3.20 (t, 5.9 Hz, H9), 3.5 (t, 5.9 Hz, H11), 3.53 ppm (m, H2). a b c Fig. S C NMR (DMS-d 6 ) of (a) DBU: δ (C), 25.79, 28.11, 29.07, 36.0 (C6), 3.51 (C9), 7.6 (C2), (C11), (C7) ppm; (b) BPA-DBU adduct: the resonances of BPA are located at δ (), 0.83 (C 2 ), (C3), (C2),.60 (C1), ppm (C), while the signals of DBU are found at δ (C), 25.2, 27.59, 28.8 (C3, C, C5), 3.98 (C6), 1.99 (C9), 7.53, (C2 and C11), ppm (C7); (c) DBU. HCl δ (C), 23.0, 25.97, 28.27, 31.12, 37.3, 7.82, (C11), ppm (C7)

13 13 a b c Fig. S19. 1 H NMR (CD 3 D) of (a) DBU: δ (m, H3, H, H5), 1.81 (quint, 5.9 Hz, H), 2.39 (m, H6), 3.19 (t), (m); (b) BPA-DBU adduct: the resonances of BPA are located at δ 1.55 (), 6.62 (dm, 8.8 Hz, H3) e 6.98 (dm, 8.3 Hz, H2) ppm, while the signals of DBU fall at δ (H3, H, H5), 2.00 (quint, 5.9 Hz, H), 2.63 (m, H6), 3.31 (H9), 3.50 (t, 6 Hz, H11), 3.56 ppm (m, H2); (c) DBU. HCl: δ (m, H3, H, H5), 2.05 (quint, 6 Hz, H), 2.71 (m, H6), 3.36 (t, 5.9 Hz, H9), 3.57 (t, 5.9 Hz, H11), 3.63 ppm (m, H2). a b c Fig. S C NMR (CD 3 D) of: (a) DBU: δ (C), 26.7, 29.1, 30.58, 36. (C6), 3.63 (C9), 9.28 (C2), (C11), ppm (C7); (b) BPA-DBU adduct: the resonances of BPA are located at δ (), 2.38 (C 2 ), (C3), (C2), (C1), ppm (C), while the signals of DBU are observed at δ (C), 25.03, 27.57, (C3-C5), (C6), 39.6 (C9), 9.5, (C2 and C11), ppm (C7); (c) DBU. HCl: δ 20.1 (C), 2.91, 27.7, 29.95, 33.69, 39.29, 9.59, (C11), 167. ppm (C7).

14 1 Mass spectrum of 1b and 2b Et C C Et (1b) 1b Fig. S21. Mass spectrum of 1b. H C Et (2b) 2b Fig. S22. Mass spectrum of 2b.