Nanocomposite γ-ferric oxide (γ-Fe2O3) mediated, green, solvent free, one pot synthesis of naturally occurring acetate esters #

Nanocomposite γ-Ferric oxide (γ-Fe

2

O

3

) mediated, green, solvent free, one pot synthesis of naturally occurring acetate esters.

Chandan P. Amonkar^*, Savio S. Dias, Anita S. Tilve

Department Of Chemistry, P.E.S.’s R.S.N. College of Arts & Science, Farmagudi, Ponda - Goa, Goa, INDIA, 403401 (affiliated to Goa University, Goa, India)

Email: cpamonkar@rediffmail.com

No. Contents Pg. No.

1. Table S1: Showing structures of starting alcohols and ester products with yields. 02

2. Table S2: γ-Fe2O3 catalysts preparation using molar ratios of FeCl3, urea and oxalic acid. 03 3. Table S3: Comparative table of synthesis of Ethyl acetate using various catalysts. 04

4. Fig. S1: FTIR spectra of γ-Fe2O3 05

5. Fig. S2: XRD pattern of γ-Fe2O3 05

6. Fig. S3: B. E. T. adsorption isotherm of γ-Fe2O3 07

7. FTIR spectra of synthesized acetate esters 09

8. ¹H NMR data for the products 10

Table S1: Showing structures of starting alcohols and ester products with yields.

Sr.

No.

Alcohol Acetate esters

% Conversion Isolated Yields

(%)

Boiling Points (^OC)

FU FO FUO

1 a

b

62 54

50 43 77

2 a b

64 54

40

45 57

3 a

b

62 49

49 41 117

4 a b

64 50 49

41 131

( Reaction Conditions: 1 mole of alcohol, 2 moles of acetic acid, 80⁰C, 4 hours, 10% wt of catalyst)

Table S2: γ-Fe2O3 catalysts preparation using molar ratios of FeCl3, urea and oxalic acid.

Catalyst Code

FeCl3

(Ratio of moles)

Urea (Ratio of moles)

Oxalic acid (Ratio of moles)

Crystallite Diameter (nm)

FU 1 1 0 34.5

FO 1 0 1 40.8

FUO Catalyst - I

1 1 1 48.1

Table S3: Comparative table of synthesis of Ethyl acetate using various catalysts.

Catalyst Weight (g)

Temperature (⁰C)

Time ( Minutes)

% Conversion

Reference

Ti pillared Clay 0.5 95 90 26 [4]

Amberlyst 15 1 70 240 51 [24]

γ-Fe2O3

FUO catalyst –I

0.2 80 240 62

Present work

Figure S1: FTIR spectra of γ-Fe2O3

FMU

FO

4000 3500 3000 2500 2000 1500 1000 500 40

50 60 70 80 90

100 FU

wavenumber (cm^-1)

%T

Fig. S1: FTIR spectra of γ-Fe2O3

Figure S2: XRD pattern of γ-Fe2O3

FUO FO

29.66 39.66 49.66 59.66 69.66 79.66

FU

Intensity

2

Fig. S2: XRD pattern of γ-Fe2O3

FTIR spectrum of catalyst-I

Catalyst characterization: Infra red spectroscopy of Fe2O3 catalyst-I: FTIR spectra were recorded using IR Prestige 21 Shimadzu spectrophotometer. FTIR spectra (fig. 1) revealed absorption bands at ~3000-3500 cm^-1 indicated the presence of O-H stretching. Absorption bands at ~1518 cm^-1 indicated the presence of O-H bending vibrations. Absorption bands at

~540-788 cm-1 indicated the presence of M-O vibrations.

FTIR spectra of Fe2O3 (catalyst-I)

4000 3500 3000 2500 2000 1500 1000 500 30

40 50 60 70 80 90 100

WAVELENGTH

%T

541.7

3310 1518.5

FTIR spectra of Fe2O3 (catalyst-I)

0.0 0.2 0.4 0.6 0.8 1.0 0.0

0.5 1.0 1.5 2.0 2.5 3.0 3.5

Relative Pressure (P/Po) Quantity Adsorbed (cm3/g STP)

Fig. S3: B. E. T. adsorption isotherm of γ-Fe2O3

Nitrogen adsorption – desorption studies were performed to determine the surface area of the γ-Fe2O3 and it was found to be 44.265 m²/g. From the B. E. T. adsorption isotherm, it can be seen that it follows type three curve which is an indication of the formation of a multilayer.

X- ray diffraction (XRD) of Fe2O3 catalyst-I: XRD spectra were recorded using ETAL APD 2000 diffractrometer using Cu kα radiation and Ni filter. (λ=1.5406 Angstrom). The scanning Braggs angle was from 10^o to 70^o. The sharp peaks depicts that the sample is crystalline in nature. The crystalline diameter was calculated for catalyst-I by using Debye – Scherer formula and was found to be 34.5nm. As shown in fig 2. XRD pattern of Iron oxide shows 100% relative intensity peak at 34.1⁰ which when compared with JCPDS data is found to match with Iron oxide catalyst.

XRD pattern of Fe2O3 (catalyst I)

10 20 30 40 50 60 70

200 400 600 800 1000 1200 1400 1600 1800

Intensity

2

Fe₂O₃

XRD pattern of Fe2O3 (catalyst I)

The FTIR spectra of synthesized acetate esters

The IR values of C=O of esters are as follows:

1b: ethyl acetate, 1748 cm^-1 2b: methyl acetate, 1750 cm^-1 3b: n-butyl acetate 1745 cm^-1 4b: isoamyl acetate 1745 cm^-1

Fig. S3: FTIR spectra of acetate esters

(1b: ethyl acetate, 2b: methyl acetate, 3b: n-butyl acetate and 4b: isoamyl acetate)

(1b) (2b)

(3b) (4b)

FTIR spectra of acetate esters (1b: ethyl acetate, 2b: methyl acetate, 3b: n-butyl acetate and 4b: isoamyl acetate)

1H NMR data for the products:

(1b) Ethyl acetate: yield = 73%; B.P. = 77^oC; IR: 1748 cm^-1 (C=O of ester);

1H NMR (Bruker, 400MHz, CDCl3): � 1.25 t 3H, 2.04 s 3H, 4.12 q 2H.

^O O

d 1.25 t 3H d 4.12 s 3H.

d 2.04 q 2H

(2b) Methyl acetate: yield = 65%; B.P. = 57^oC; IR: 1750 cm^-1 (C=O of ester);

1H NMR (Bruker, 400MHz, CDCl3): � 2.08 s 3H, 3.69 s 3H.

^O O

d 3.69 s 3H.

d 2.08 s 3H

(3b) n-Butyl acetate: yield = 71%; B.P.= 126^oC; IR: 1745 cm^-1 (C=O of ester);

1H NMR (Bruker, 400MHz, CDCl3): � 0.93 t 3H, 1.38 m 2H, 1.60 m 2H, 2.05 s 3H, 4.06 t 2H.

d 4.06t 3H.

d 2.05 s 3H

O O

d 0.93 t 3H

d 1.38 m 2H d 1.60 m 2H

(4b) Isoamyl acetate: yield = 71%; B.P. =142^oC; IR: 1745 cm^-1 (C=O of ester);

1H NMR (400MHz, CDCl3): � 0.93 d 6H, 1.52 q 2H, 1.70 m 1H, 2.04 s 3H, 4.09 t 2H.

d 4.09 t 3H.

d 2.04 s 3H

d 0.93 d 3H d 1.70 m 1H d 1.52 m 2H

O O

d 0.93 d 3H