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Supplementary information

Phosphonate Functionalized Carbon Spheres as Brønsted Acid Catalysts

for Valorization of bio-renewable α-Pinene Oxide to trans-Carveol Amravati S. Singh a,b, Jacky H. Advani a,b,, and Ankush V. Biradar a,b,*aInorganic Materials and Catalysis Division, CSIR-Central Salt and Marine Chemicals

Research Institute (CSIR-CSMCRI), G. B. Marg, Bhavnagar-364002, Gujarat, IndiabAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh,

India

*Corresponding author: Tel.: +91 278 2567760 Ext: 7170; Fax: +91 278 2566970

Email: ankush@csmcri.res.in

This SI contains 10 pages, 1 table, 18 Figures

Contents Page No.

S1.

S2.

S3.

S4.

S5.

S6.

S7.

S8.

S9.

S10.

S11.

S12.

Material Characterizations

Scanning electron microscopy (SEM)

Solid 13C and 31P CP MAS NMR spectrum of CS(α) and PCS(γ)

XPS survey spectrum of PCS(α2)

Acidic strength calculations of PCS (α2) determine by ICP- OES

Effect of PCS(α2) amount on the distribution of the products in the

isomerization of α- pinene oxide

Recyclability of the catalyst PCS(α2)

The activity of the catalyst after Hot filtration test

SEM and EDAX images of recycled PCS (α2)1H and 13C NMR analysis of trans-Carveol

Fourier transform infrared spectroscopy (FT-IR) of trans-Carveol

GC-MS profile of the products obtained in the isomerization of α-

pinene oxide

2

3-4

5

5

5-6

6

6

7

7

7

8

9-10

Electronic Supplementary Material (ESI) for Dalton Transactions.This journal is © The Royal Society of Chemistry 2020

2

S1. Materials characterizations

The structural characterization studies of the catalyst were carried out by different

physiochemical methods. The PXRD analysis was carried out using Philips X’pert MPD

system for powder X-ray Diffractometer. The black powder obtained was scanned in the range

of 10-80° using Cu Kα radiation of 1.54056 Å wavelength with a Ni filter. A Perkin-Elmer GX

spectrophotometer was used for the Fourier-transform infrared spectrophotometry (FTIR)

spectra using KBr pellets in the wavelength range of 400-4000 cm-1. The energy dispersive X-

ray (EDX) mapping and morphology of the catalyst was determined using a JEOL JSM 7100F

field emission scanning electron microscope (FE-SEM). The synthesized catalyst was

dispersed in isopropyl alcohol by sonication and was drop casted on a brass stub. The stub was

dried under vacuum and used for analysis. Transmission electron microscope (TEM) (JEOL

JEM 2100) was used to analyze the size and shape of the particles and recording the selected

area electron diffraction (SAED) of the sample. The samples were loaded on the TEM grid by

dispersing it in isopropyl alcohol using ultrasonicator and then drop-casting the suspension on

the TEM grid. This drop casted grid was dried in a vacuum oven before analysis. X-ray

photoelectron spectroscopy (XPS) was performed using an ESCA+ (Omicron Nanotechnology,

Germany) with a monochromatized Al-Kα X-ray (hν = 1486.7 eV) as the excitation source (15

kV and 20 mA). The pass energy for the survey spectrum was 50 eV and 20 eV in case of the

short scan. The sample was placed on the copper tape and degassed in the XPS FEL chamber

to minimize the air contamination. A charge neutralizer of 2 keV was used to overcome any

charging problem, and the calibration was done using the adventitious C 1s feature at 284.6 eV

as a reference. All the spectra’s were recorded at 90° of the X-ray source. 31P and 13C solid-

state nuclear resonance (NMR) spectroscopy was performed using a Bruker 11.7 T

spectrometer equipped with a triple resonance 2.5 mm solid-state probe head and an avance III

console. Samples were prepared for NMR by ultrasonic ion in acetone for 5 min, then dried at

80°C, and filled into a 2.5 mm zirconia rotor. All experiments were performed at room

temperature, either in static mode or while spinning the sample at 20kHz magic angle spinning

(MAS) frequency. The 31P chemical shift was determined with reference to 85% H3PO4 in D2O

and the 13C chemical shift was determined with reference to Si(CH3)4. The number of transients

recorded was 2000 for 31P NMR experiments, and 16000-24000 for 13C NMR experiments.

The classical Hahn echo pulse sequence was used for 31P NMR experiments, and a simple 30°-

one pulse excitation sequence was used for all 13C NMR and 31P NMR experiments (as

indicated). All spectra were acquired without decoupling. The recycle delay was set to 2s, the

3

echo delay to 0.2 ms, and the pulse length for 90° flip angle experiments to 5 µs for 31P NMR

experiments. The thermogravimetric analysis (TGA) was carried out on a Mettler TGA/DTA

851e instrument at a nitrogen flow rate of 50 mL/min. The surface area of the catalyst was

obtained using the ASAP 2010, Micromeritics Sorptometer at 7.4 K. The sample was degassed

at 150 ºC for 10h prior to sorption. ICP- OES analysis done by Perkin Elmer, optima, 2000

instrument.

S2. Scanning electron microscopy (SEM)

S2.1. SEM images of CS(α)

Fig. S1. Scanning electron microscopy (SEM) image of CS(α) (A-C).

S2.2. SEM images of PCS(α1)

Fig. S2: SEM images of PCS(α1) (A-D) and SEM elemental mapping of PCS(α1) where E

shows overall mapping, F- shows phosphorous, G-shows oxygen and H-shows carbon. And I

shows the SEM-EDAX of the sample. And Table shows the % availability of the elements.

4

S2.3. SEM and EDAX images of CS(γ)

Fig. S3. Scanning electron microscopy image of CS(γ) (A-D) and E show the SEM-EDAX of

the sample and Table shows the the % availability of the elements.

S2.4. SEM images of PCS(γ)

Fig. S4: Scanning electron microscopy (SEM) image of PCS(γ) (A-C) and D show the SEM-

EDAX of the sample. And Table shows the % availability of the elements.

5

S3. Solid 31P and 13C NMR of CS (γ) and PCS (γ)

-90-50-10205080120160f1 (ppm)

0.2

37

.62

18

.61

39

.75

-40-20020406080110140170200230f1 (ppm)

12.7

2

28.5

2

36.3

3

64.6

0

110.

62

150.

06

176.

64

209.

67

Fig. S5. (a) Solid-state 31P NMR of PCS (γ) (b) Comparison solid 13C NMR of CS (γ) and

PCS (γ).

S4: XPS survey spectrum of PCS (α2)

1200 1000 800 600 400 200 0

Inte

nsity

Binding Energy (E) (eV)

O1s

C1s

P2pP2s

Fig. S6. X-ray photoelectron spectroscopy (XPS) survey spectrum of PCS(α2).

S5: Acidic strength calculations of PCS (α2) determine by ICP- OES

The 100 mg of PCS(α2) catalyst was digested Aqua regia solution and analyzed by ICP-OES.

The P continent was found 1.33 wt%

Mole of P was calculated as fallows:

100 mg = 1.33 wt% of phosphorus

=1.33 mg phosphorus in 100 mg PCS(α2)

=13.3 mg phosphorus in 1000 mg PCS(α2)

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13.3 mg = 0.0133g phosphorus

Moles of phosphorus = Weight/Mol. Wt (MW of P-30.97)

= 0.0133/30.97

= 0.00042 moles/g

= 0.42 mmoles/g of phosphorus

S6. Table S1. Effect of PCS(α2) amount on the distribution of the products in the isomerisation

of α- pinene oxide.

Entry Selectivity (%)Weight

(mg)

Conv.

(%)TCV CPA TPC Others

1. 10 71 66 20 7 7

2. 20 80 66 21 7 6

3. 30 88 67 19 6 8

4. 40 94 67 20 7 6

Reaction condition: α- pinene oxide: 0.5 g (3.28 mmol); Catalyst: PCS (α2): Solvent: DMF (2

mL); Temp. : 140 °C; Time: 1 h.

S7. Recyclability of the catalyst PCS(α2)

100 98 96 95 9080

67 67 66 65 67 66

0 1 2 3 4 50

20

40

60

80

100

% C

onve

rsio

n/ S

elect

ivity

Recycle Time

% Conversion % Selectivity

Fig. S7. Recyclability of PCS(α2) catalyst.

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S8. Activity of the catalyst after Hot filtration test

0 20 40 60 80 100 120 140 160 180

0

20

40

60

80

100

Con

vers

ion

Time (min)

con. after cat. removed Selectivity of TCV con. after without cat. removed Selectivity of TCV

Fig. S8. Activity of the catalyst after Hot filtration test.

S9: SEM and EDAX images of recycled PCS (α2)

Fig. S9. Scanning electron microscopy (SEM) image of recycled PCS(α2) (A-D) and E show

the SEM-EDAX of the sample. And Table shows the % availability of the elements.

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S10. 1H and 13C NMR analysis of trans-Carveol1H NMR of trans-Carveol CDCl3 (600 MHz) δ 5.59 (s, 1H), 4.75 (s, 2H), 4.02 (s, 1H), 2.34

(s, 1H), 2.13 (s, 1H), 1.93 (s, 1H), 1.85 (s, 1H), 1.80 (s, 3H), 1.75 (s, 3H), 1.61 (s, 2H)

Fig. S10. 1H NMR of trans-Carveol

13C NMR of trans-Carveol CDCl3 (600 MHz) δ 148.17 (s), 133.29 (s), 124.35 (s), 108.01

(s), 67.52 (s), 35.71 (s), 34.20 (s), 29.98 (s), 28.69 (s), 19.85 (s).

Fig. S11. 13C NMR of trans-Carveol.

0.20.61.01.41.82.22.63.03.43.84.24.65.05.4f1 (ppm)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

2.28

3.19

3.04

1.37

1.08

1.06

1.10

1.02

2.08

1.00

1.26

1.61

1.75

1.80

1.85

1.93

2.13

2.34

4.02

4.75

5.59

CH3

CH3

OHH

H

H2.02.53.03.54.04.55.05.5f1 (ppm)

0.0

0.5

1.0

2.28

3.19

3.04

1.37

1.08

1.06

1.10

1.02

2.08

1.00

1.61

1.75

1.80

1.85

1.93

2.13

2.34

4.02

4.75

5.59

0102030405060708090100110120130140150f1 (ppm)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

20.9

8

30.9

935

.30

36.8

1

68.7

4

109.

10

125.

44

134.

39

149.

33

CH3

CH3

OHH

H

H

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S11. FTIR spectrum of trans-Carveol.

Fig. S12. Fourier transform infrared spectrum of trans-Carveol.

S12. GC-MS profile of the selected products.

Fig. S13. GC-MS profile for Campholenic aldehyde.

Fig. S14. GC-MS profile for trans-Carveol.

4000 3500 3000 2500 2000 1500 1000 500

% T

rans

mitt

ance

Wavenumber(cm-1)

trans-Carveol

29203341

3083

2727

2342

16441441

1376

1261 1167

1055

962

808

616524672

OO

10

Fig. S15. GC-MS profile for trans-pinocarveol.

Fig. S16. GC-MS profile for trans-Sobrerol.

Fig. S17. GC-MS profile for trans-Pinocarvone.

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