SUPPORTING INFORMATION. Elucidation of the role of betaine hydrochloride in glycerol esterification: towards bio-based ionic building blocks

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1 Electronic Supplementary Material (ESI) for Green Chemistry. This journal is The Royal Society of Chemistry 2017 SUPPORTING INFORMATION Elucidation of the role of betaine hydrochloride in glycerol esterification: towards bio-based ionic building blocks C. Journoux-Lapp, a K. De Oliveira Vigier, a C. Bachmann, a S. Marinkovic, b B. Estrine, b G. Frapper a * and F. Jérôme a * a. Institut de Chimie des Milieux et Matériaux de Poitiers, CNRS/Université de Poitiers, 1 rue Marcel Doré, ENSIP, TSA Poitiers cedex 9 (France). b. ARD-Agro-industrie Recherches et Développements, Green Chemistry Department, Route de Bazancourt, F Pomacle, France. Corresponding authors: francois.jerome@univ-poitiers.fr (experimental part) gilles.frapper@univ-poitiers.fr (theoretical part) Contents 1. Theoretical calculations and full Gaussian09 reference... p. S2 2. Computed energies... p. S2 3. Energetic profile (primary hydroxyl model).. p. S4 4. Optimized structures, Cartesian coordinates p. S5 5. Thermodynamic modelling.. p. S23 6. Synthesis and characterization of acidified betaine.. p. S23 7. Synthesis and characterization of glyceryl betaine ester (GlyGB).. p. S26

2 1. Theoretical Calculations All structures were studied using the B3LYP method 1 of the density functionnal theory. The structures were fully optimized using the 6-31+G(d,p) basis sets (B3LYP/6-31+G(d,p)). Enthalpies and Gibbs free energies were computed at K without scaling vibrational frequencies. All calculations were performed with the Gaussian 09 package Computed energies Table S1. Total electronic energies (E e ), zero-point corrected electronic energies (E ZPE ), enthalpies (H 298 ) and Gibbs free energies (G 298 ) for gas phase compounds at K. Compounds Structures E e a E ZPE H 298 G 298 G b GB glycine betaine (zwitterion) HCl GB GB1 GB (Betaine hydrochloride) GB GB GB1-5 (HCl) c GB1-6 (HCl) GB GB GB GB1 dimer (GB1) , , , , (GB1) , , , , (GB1) 2-3 (HCl) (GB1) 2-4 (HCl) (GB1) , , , , a Electronic structure calculations at the B3LYP/6-31+G(d,p) level. All values are in atomic units (1a.u. = kcal/mol). b Relative Gibbs free energies in kcal/mol. c This structure contains non-dissociated HCl unit. S2

3 Table S2. Total electronic energies (E e ), zero-point corrected electronic energies (E ZPE ), enthalpies (H 298 ) and Gibbs free energies (G 298 ) for gas phase structures involved in the reaction profiles. Reaction profile for GB1 + HCl + secondary hydroxyl glycerol Structures E e a E ZPE H 298 G 298 G b R TS TI TI TS P Reaction profile for GB1 + HCl + primary hydroxyl glycerol Structures E e a E ZPE H 298 G 298 G b R TS TI TI TS P a Electronic structure calculations at the B3LYP/6-31+G(d,p) level. All values are in atomic units (1a.u. = kcal/mol). b Relative energies in kcal/mol. S3

4 3. Energetic profile (primary hydroxyl) R O 1 H 1 R 2 C O O 3 H TS Cl 2.24 H 2 R 1 O 1 TS2 R 2 C H O2 Cl O 3 H 1.00 H TS G (kcal//mol) R 0 TS TI TI P 5.9 nucleophilic addition of alcohol H 2 O elimination Figure S1. Computed B3LYP/6-31+G(d,p) Gibbs free energy profiles for the C-O bond formation step (primary hydroxyl) and H 2 O elimination step in the esterification reaction and calculated transition state structures. The Gibbs free energy are given in kcal.mol -1 and distances are in angstroms. S4

5 4. Optimized structures - Betaine (zwitterion) GB - gas phase HCl - Betaine hydrochloride GB1 (nine structures, GB1-1 to GB1-9) - Betaine dimers: (GB1) 2 (five structures) - Equilibrium structures (R, TI1, TI2, P) and transition structures (TS1, TS2) for HCl-catalyzed esterification reaction profiles: - GB1 + HCl + sec-glycerol - GB1 + HCl + prim-glycerol R: Reactant structure, i.e., (GB + HCl + glycerol) van der Waals complexe TS1: HCl-catalyzed nucleophilic addition transition structure TI1: tetrahedral intermediate resulting from nucleophilic addition TI2: rearranged tetrahedral intermediate TS2: HCl-catalyzed H 2 O elimination transition structure P: Product structure, i.e., (ester + HCl + H 2 O) Van der Waals complexe Cartesian Coordinates in Å Glycine Betaine (zwitterion) GB N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , HCl H,0,0.,0., Cl,0,0.,0., S5

6 GB1-1 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-2 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-3 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , S6

7 C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-4 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-5 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , S7

8 H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-6 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-7 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S8

9 H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-8 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , GB1-9 C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , S9

10 (GB1) 2-1 N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , (GB1) 2-2 N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , S10

11 C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , (GB1) 2-3 N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S11

12 H,0, , , H,0, , , H,0, , , Cl,0, , , Cl,0, , , H,0, , , N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , (GB1) 2-4 N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , S12

13 O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , (GB1) 2-5 N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S13

14 H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , R (Esterification of GB1 + HCl + secondary glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , H,0, , , TS1 (Esterification of GB1 + HCl + secondary glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , S14

15 C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , H,0, , , TI1 (Esterification of GB1 + HCl + secondary glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S15

16 Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , H,0, , , TI2 (Esterification of GB1 + HCl + secondary glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S16

17 Cl,0, , , H,0, , , TS2 (Esterification of GB1 + HCl + sec-glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , H,0, , , P (Esterification of GB1 + HCl + secondary glycerol) N,0, , , C,0, , , C,0, , , C,0, , , O,0, , , C,0, , , O,0, , , C,0, , , S17

18 H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , C,0, , , O,0, , , C,0, , , C,0, , , O,0, , , O,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , H,0, , , R (Esterification of GB1 + HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , O,0, , , H,0, , , S18

19 C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , TS1 (Esterification of GB1 + HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , O,0, , , H,0, , , C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , S19

20 TI1 (Esterification of GB1 + HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , Cl,0, , , O,0, , , H,0, , , C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , TI2 (Esterification of GB1 + HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , S20

21 H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , O,0, , , Cl,0, , , C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , TS2 (Esterification of GB1 + HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , O,0, , , Cl,0, , , C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , S21

22 Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , P (Esterification of GB1+ HCl + primary glycerol) C,0, , , C,0, , , O,0, , , O,0, , , N,0, , , C,0, , , C,0, , , C,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , H,0, , , O,0, , , Cl,0, , , C,0, , , H,0, , , H,0, , , C,0, , , H,0, , , Cl,0, , , H,0, , , O,0, , , C,0, , , H,0, , , H,0, , , H,0, , , O,0, , , H,0, , , S22

23 5. Thermodynamic modelling Considering that the esterification reaction takes place from an initial pre-reactional complex and evolves through a rearrangement of this system, a first order rate law can be written: d[product] / dt = k [ pre-reactional complex ] In the context of the transition state theory, the rate constant k is given by the Eyring equation: k = k B T/h exp(- G /RT) The initial rate d[product] / dt is determined from the experimental data (initial concentration:4.88 M and a yield of 10% after 50 mn), giving M.s -1. The critical point is the initial concentration of the pre-reactional complex since the amount of nondissociated HCl molecules in the reactive medium is unknown. At this point we suggest two hypotheses: 1 st hypothesis: The amount of non-dissociated HCl is 1% of the betaine hydrochloride initial amount, i.e., M in our experimental conditions. Using the Eyring equation (150 C), we deduce: G = 29.9 kcal.mol nd hypothesis: The amount of non-dissociated HCl is 0.1% of the betaine hydrochloride initial amount, i.e., M in our experimental conditions. Using the Eyring equation as above we deduce: G = 27.9 kcal.mol -1. Even though it is difficult to choose the more reasonable hypothesis (additive experimental results could help to this end), note that the estimated G are in reasonable agreement with the theoretical energetic profile values (31-32 kcal/mol). 6. Synthesis and characterization of acidified betaine 6.1. General procedure for the synthesis of GB2-5: Except for GB1 which is commercially available (purchased to Sigma-Aldrich), all other acidified glycine betaine derivatives GB2-5 were prepared as follow: GB (1mol) was mixed with 1.4 eq of acid and stirred for 20 min at room temperature (exothermic reaction). Then, the as-obtained paste was washed twice with 50 ml of absolute ethanol to remove the excess of acid. After washing, the corresponding GB2-5 were obtained as a white solid in a nearly quantitative yield (95%). Next, GB2-5 were dried at 80 C in an oven for one hour to remove potential trace of ethanol. S23

24 Conversion (%) Conversion (%) Glycerol + GB Time (min) Glycerol + GB Time (min) Conversion (%) glycerol GB Conversion (%) Time (min) Glycerol + GB3 Glycerol + GB Time (min) Figure S2. Typical kinetic profiles collected at 150 C 6.2. Characterizations of GB2-5 N OH O HSO 4 1-carboxy-N,N,N-trimethylmethanaminium hydrogenosulfate (GB3) Isolated yield : 95% FT-IR : ʋ (cm -1 ) : 1738 cm -1 (C=O), (-CH 2, -CH 3 ). NMR 1 H (400 MHz, D 2 O): δ (ppm): 3.23 (s, 9H, N + (CH 3 ) 3 ), 4.13 (s, 2H, -CH 2 ). RMN 13 C (100 MHz, D 2 O): δ (ppm): (-N + (CH 3 ) 3 ), (-CH 2 ), (-C=O). HRMS (ESI + ) : [C 5 H 12 NO 6 S]: m/z = [M + ] S24

25 N OH O O 3 SCH 3 1-carboxy-N,N,N-trimethylmethanaminium methanesulfonate (GB2) Isolated yield : 95% FT-IR : ʋ (cm -1 ) : 1733 cm -1 (C=O), (-CH 2, -CH 3 ). NMR 1 H (400 MHz, D 2 O) : δ (ppm): 2.71 (s, 1H, CH 3 SO 3- ), 3.24 (s, 9H, N + (CH 3 ) 3 ), 4,13 (s, 2H, -CH 2 ). NMR 13 C (100 MHz, D 2 O) : δ (ppm): (CH 3 SO 3- ), (-N + (CH 3 ) 3 ), (-CH 2 ), (-C=O). HRMS (ESI + ) : [C 6 H 14 NO 5 S]: m/z = [M + ] N OH O O 3 SCF 3 1-carboxy-N,N,N-trimethylmethanaminium trifuoromethanesulfonate (GB4) Isolated yield : 95% FT-IR : ʋ (cm -1 ) : 1743 cm -1 (C=O), (-CH 2, -CH 3 ). NMR 1 H (400 MHz, D 2 O): δ (ppm): 3.27 (s, 9H, N + (CH 3 ) 3 ), 4.20 (s, 2H, -CH 2 ). NMR 19 F (376 MHz, D 2 O): δ (ppm): ppm (-CF 3 ). NMR 13 C (100 MHz, D 2 O): δ (ppm): (-N + (CH 3 ) 3 ), (-CH 2 ), (q, 1 J CF = 315 Hz, CF 3 ), (-C=O). HRMS (ESI + ) : [C 6 H 11 NO 5 SF 3 ]: m/z = [M + ] S25

26 N OH O O 3 SC 6 H 4 CH 3 1-carboxy-N,N,N-trimethylmethanaminium p-toluenesulfonate (GB5) Isolated yield : 95% FT-IR : ʋ (cm -1 ) : 1734 cm -1 (C=O), (-CH 2, -CH 3 ). NMR 1 H (400 MHz, D 2 O): δ (ppm) : 1.98 (s, 3H, -CH 3 ), 2.88 (s, 9H, -N + (CH 3 ) 3 ), 3.85 (s, 2H, -CH 2 ), 6.95 (d, 2H, 3 J HH =8 Hz, =CH), 7,40 (d, 2H, 3 J HH =8Hz, =CH). RMN 13 C (100 MHz, D 2 O): δ (ppm) : (-CH 3 ), (-N + (CH 3 ) 3 ), (CH 2 ), (Ar), (Ar), 139,98 (Ar), 141,89 (Ar), (-C=O). HRMS (ESI + ) : [C 12 H 18 NO 5 S]: m/z = [M + ] 7. Synthesis and characterization of glyceryl betaine ester (GlyGB) 7.1. General procedure for the synthesis of GB derivatives: GB1-5 (1mol) was mixed with 1 eq. of glycerol and heated at 150 C in an opened round bottom flask equipped with a magnetic stirring bar (stirring rate = 1000 rpm). The reaction progress was monitored by GC and HPLC analysis. For the characterization of glyceryl betaine esters, the reaction media was washed with 50 ml of 2-propanol at the end of the reaction. This washing removed unreacted glycerol and/or trace of in situ produced polyglycerol. The residue was composed of (poly)glyceryl betaine ester and, in some cases, of unreacted GB1-5. GC Analysis: Products were silylated before analysis according to the procedure described by Lee and al. 3 The GC Varian 3900 was equipped with a capillary column BP5 (L = 30m, Ø = 0.32µm, thickness = 1 µm) and an ionisation flame detector. The temperature of the injector was fixed at 250 C. The program used is as follow : 90 C to 120 C (10 C/min) and then 120 C to 290 C (20 C/min), final temperature was holden during 20 minutes. HLPC Analysis : Conversion of acidified betaine was determined by external calibration at 70 C using a HPLC Shimadzu apparatus composed of a Zorbax NH2-column ( mm), a Shimadzu LC-20AD pump, a Shimadzu Waters 2014 detector and using a mixture acetonitrile/water (20:80) as mobile phase (0.4 ml min -1 ) Characterization of glyceryl betaine ester (GlyGB) For the sake of clarity, all the following data correspond the esterification of glycerol on the primary hydroxyl group. Note that esterification on the secondary position also occurs but in a much lower extent. S26

Supporting Information

Electronic Supplementary Material (ESI) for RSC Advances. This journal is The Royal Society of Chemistry 2014 Supporting Information Rh 2 (Ac) 4 -Catalyzed 2,3-Migration of -rrocenecarboxyl -Diazocarbonyl