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When [P8,8,8,1][H
step was carried out as above described: a mixture of BnOH
97.0 mmol, 10 mL), DMC (9.7 mmol, 0.8 mL), and the orga-
3
COCO
2
] was used, the transesterication
Tetrahedron, 2000, 56, 8207–8237; (c) B. Sch ¨a ffner,
F. Sch ¨a ffner, S. P. Verevkin and A. B ¨o rner, Chem. Rev.,
2010, 110, 4554–4581.
(
nocatalyst (48 mg; 0.01 molar equiv. with respect to DMC) was
set to react at 90 C, for 4.5 hours. Once the reaction was
2 P. Tundo and M. Selva, Acc. Chem. Res., 2002, 35, 706–716.
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D. Brunelli, J. Org. Chem., 2006, 71, 5770–5773; (f) M. Selva,
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463–468; (g) M. Selva and A. Perosa, Green Chem., 2008, 10,
457–464; (h) M. Selva, A. Perosa and M. Fabris, Green
Chem., 2008, 10, 1068–1077; (i) M. Selva and M. Fabris,
Green Chem., 2009, 11, 1161–1172; (j) M. Selva, M. Fabris
and A. Perosa, Green Chem., 2011, 13, 863–872; (k) M. Selva,
V. Benedet and M. Fabris, Green Chem., 2012, 14, 188–200;
ꢀ
complete, the phosphonium salt was removed by adsorption on
a silica gel pad (3 g) through which the reaction mixture was
eluted. Then, BnOH and BnMC were distilled under vacuum. A
partial conversion of DBnC back to parent BnMC and BnOH was
promoted by traces of the phosphonium salt that were still
present during the distillation. DBnC was nally puried aer
washing with n-pentane (1 mL) and isolated in a 47% yield.
For both CsF/a-Al O and [P8,8,8,1][H COCO ], the above
2 3 3 2
described procedures were also used by increasing the cat–DMC
molar from 0.01 to 0.05.
Mass index. MI was calculated for the reaction step of all
5
methods listed in Table 4. The following expression was used:
P
reagents þ catalyst þ solvents ðKgÞ
MI ¼
Product ðKgÞ
(
l) M. Selva, M. Noe, A. Perosa and M. Gottardo, Org.
Biomol. Chem., 2012, 10, 6569–6578.
Atom economy. AE was calculated according to the following
equation:
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2004, 69, 3953–3956.
5 Green Chemistry Metrics: Measuring and Monitoring
Sustainable Processes, ed. A. Lapkin and D. Constable, John
Wiley & Sons, Chichester, 2008.
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749–752; (b) G. Rokicki, J. Pawlicki and W. Kuran, Polym. J.,
1982, 14, 839–845; (c) J. A. Cella and S. W. Bacon, J. Org.
Chem., 1984, 49, 1122–1125; (d) W. McGhee and D. Riley,
J. Org. Chem., 1995, 60, 6205–6207.
7 (a) A. A. G. Shaikh and S. Sivaram, Ind. Eng. Chem. Res., 1992,
31, 1167–1170; (b) R. Srivastava, D. Srinivas and
P. Ratnasamy, J. Catal., 2006, 241, 34–44.
22
ꢁ1
MW ðg mol Þ product
AE ¼ P
ꢁ1
MW ðg mol Þ reagents
Characterization data. All compounds were characterised by
1
GC-MS and H NMR. Spectroscopic properties were in agree-
ment to those reported in the literature.
4
a,23
1
Dibenzyl carbonate (BnC).
K, d): 7.41–7.30 (m, 10H), 5.18 (s, 4H). C NMR (101 MHz,
CDCl , 298 K, d): 155.23, 135.31, 128.73, 128.68, 128.47, 69.88.
H NMR (400 MHz, CDCl , 298
3
1
3
3
+
EI-MS (70 eV): 180 [M ꢁ 62] (10); 151 (12); 107 (41); 92 (24);
9
(
7
1 (100); 79 (40); 77 (24); 65 (22); 51 (13). IR (KBr): 1744 (br); 1456
sh); 1385 (sh); 1259 (br); 1224 (br); 934 (sh); 907 (sh); 788 (sh);
ꢀ
47 (sh); 695 (sh); 591 (sh); 482 (sh). Mp ¼ 32–33 C.
3l
+
Benzyl methyl carbonate (BnMC). EI-MS (70 eV): 166 [M ] (23);
1
21 (13); 107 (42); 92 (11); 91 (100); 90 (47); 89 (21); 79 (33); 77
(
(
32); 65 (25); 63 (10); 51 (20); 50 (10).
8 (a) K. Abe, I. Akikazu, Eu Pat., EP 2330096, 2009; (b)
D. Chaturvedi, N. Mishra and V. Mishra, Tetrahedron Lett.,
2007, 48, 5043–5045.
+
Dibenzyl ether (DBnE). EI-MS (70 eV): 107 [M ꢁ 91] (14); 92
100); 91 (89); 79 (16); 77 (21); 65 (24); 51 (14); 44 (10). Database
NIST: Ref. #118448, match quality 94%.
9 J. L. R. Williams, D. D. Reynolds, K. R. Dunham and
J. F. Tinker, J. Org. Chem., 1959, 24, 64–68.
+
Benzyl octyl carbonate. EI-MS (70 eV): 112 [M ꢁ 76] (8); 84
(
(
54); 83 (46); 77 (100); 70 (45); 69 (40); 67 (12); 59 (15); 57 (26); 56 10 J.-M. Clacens, D. Genuit, B. Veldurthy, G. Bergeret,
40); 55 (49). Database NIST: Ref #314620, match quality 89%. L. Delmotte, A. Garcia-Ruiz and F. Figueras, Appl. Catal., B,
004, 53, 95–100.
2
1
1 M. Fabris, V. Lucchini, M. No `e , A. Perosa and M. Selva,
Chem.–Eur. J., 2009, 15, 12273–12282.
Acknowledgements
Prof. Paolo Pavan (Dipartimento di Scienze Ambientali, Infor- 12 (a) B. Veldurthy, J.-M. Clacens and F. Figueras, J. Catal., 2005,
matica e Statistica, Universit `a Ca’ Foscari Venezia) is kindly
acknowledged for his support in ion-cromatography analyses.
229, 237–242; (b) B. Veldurthy, J.-M. Clacens and F. Figueras,
Eur. J. Org. Chem., 2005, 1972–1976; (c) J. Ni, D. Rooney and
F. C. Meunier, Appl. Catal., B, 2010, 97, 269–275.
1
3 C. J. Bradaric, A. Downard, C. Kennedy, A. J. Robertson and
Y. Zhou, Green Chem., 2003, 5, 143–152.
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1936 | RSC Adv., 2014, 4, 1929–1937
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