Cetyltrimethylammonium dichromate: A phase-transferring oxidant

Article abstract of DOI:10.1081/SCC-200054191

A phase-transferring oxidant, cetyltrimethylammonium dichromate (CTADC) has been prepared and characterized from elemental analysis and spectral data. Application of this reagent to oxidize alcohols, aldehyde, and cinnamic acid is reported. Copyright Taylor & Francis, Inc.

Full text of DOI:10.1081/SCC-200054191

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Cetyltrimethylammonium Dichromate: A
Phase‐Transferring Oxidant
Sabita Patel a , Minati Kuanar a , Biswa B. Nayak a , H. Banichul a & Bijay K.
Mishra a
a Center of Studies in Surface Science and Technology, Department of
Chemistry , Sambalpur University , Jyoti Vihar, India
Published online: 16 Aug 2006.
To cite this article: Sabita Patel , Minati Kuanar , Biswa B. Nayak , H. Banichul & Bijay K. Mishra (2005)
Cetyltrimethylammonium Dichromate: A Phase‐Transferring Oxidant, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 35:8, 1033-1037, DOI:
10.1081/SCC-200054191
To link to this article: http://dx.doi.org/10.1081/SCC-200054191
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Synthetic Communicationsw, 35: 1033–1037, 2005
Copyright # Taylor & Francis, Inc.
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1081/SCC-200054191
Cetyltrimethylammonium Dichromate:
A Phase-Transferring Oxidant
Sabita Patel, Minati Kuanar, Biswa B. Nayak, H. Banichul, and
Bijay K. Mishra
Center of Studies in Surface Science and Technology, Department of
Chemistry, Sambalpur University, Jyoti Vihar, India
Abstract:
A phase-transferring oxidant, cetyltrimethylammonium dichromate
(CTADC) has been prepared and characterized from elemental analysis and spectral
data. Application of this reagent to oxidize alcohols, aldehyde, and cinnamic acid is
reported.
Keywords: Cetyltrimethylammonium dichromate, phase-transferring agent, oxidation
In continuation of our search for novel oxidizing agents suitable for substrates
in organic solvents, we have made an attempt to synthesize and establish
cetyltrimethylammonium dichromate as a phase-transferring agent. Cetyl-
trimethylammonium (CTA) ion is well known for its amphipathicity, that
is, having the characteristics of being solubilized in both aqueous and non-
aqueous media. Unlike other quaternary ammonium ions (tetra butyl or
octyl ammonium ions), CTA has a relatively small head group with more
exposed charge and a well-balanced hydrophobic group to carry the ion to
both water and organic media. Onium with its counterion forms a tight ion
pair in organic solvents, whereas in aqueous medium it dissociates.[1] CTA
with bromide as the counterion can form micelle in aqueous medium and
can form reversed micelle in chloroform.
Received in India December 4, 2004
Address correspondence to Bijay K. Mishra, Center of Studies in Surface Science
and Technology, Department of Chemistry, Sambalpur University, Jyoti Vihar
768 019, India. E-mail: bijaym@hotmail.com

1034
S. Patel et al.
Previously we reported the oxidation kinetics using cetyltrimethyl-
ammonium permanganate (CTAP)[2] on styrylpyridinium dyes,[3] substituted
cinnamates[4] and cis-olefinic double bonds.[5] We have also synthesised
cetyltrimethylammonium ceric nitrate (CTACe) and reported the oxidation
behavior of this oxidant toward several organic substrates.[6] CTAP and
CTACe can react effectively on organic substrates without any acid catalyst.
Oxidative applications of chromium(VI) range from oxidation of
methylene group to carboxylic acids, which yields corresponding oxidized
products. To carry Cr(VI) to organic solvents a variety organic carriers have
been used. Onium ions are found to be highly successful as carriers of these
counter ion.[7–15] Similar to normal ion exchangers, cetyltrimethyl
ammonium ions can easily trap dichromate ions to form cetyltrimethyl-
ammonium dichromate (CTADC, 1). The elemental analysis clearly
envisages the presence of two CTA units per molecule of dichromate. The
IR and NMR spectral data also supports the presence of CTA in the
oxidant. The IR band at 933 cm21 is evidence of the presence of a Cr-O
group in the molecule.[16] Similarly, the chemical shift values around 3.42
and 3.51d, because of the onium methylene groups also support a closeness
of the dichromate anion to the onium ion. In cetyltrimethylammonium
bromide and cetyltrimethylammonium ceric nitrate these values appear at
around 4.1 and 3.8 d, respectively.[6]
¼
½C16H33Nþ ðCH3Þ3ꢀ2Cr2O7
1
CTADC is found to be water insoluble and soluble in most of the organic
solvents. The Cr(VI) band ranges from 353 in dioxane to 383 in dichloro-
methane. CTADC is found to be stable in these solvents at reflux temperature
and for an appreciable time period (24 h). Cetyl trimethyl permanganate has
been reported to be unstable in solution and it is found to oxidize the CTA
ion to corresponding pentadecanal.[2] In the present experimental conditions
the substrates were refluxed with the oxidant in dicholoromethane for 0.5 to
6 h and the products were isolated by the solvent-extraction method from
the reaction mixture. The products were identified by comparing the IR
spectral data and melting/boiling points of the products or their derivatives.
The experimental conditions and analytical data of the products are given in
Table 1.
EXPERIMENTAL
General
Melting point and boiling (Siwoloboff’s method)[17] points of the oxidation
products and the 2,4-dinitro phenyl hydrazones were measured in an acid

Table 1. Reaction condition and product analysis of the oxidation reactions using CTADC
Reflux
time (h)
Yield
(%)
Melting/boiling point
(8C, literature value)[17]
Melting point of 2,4-DNPH
(literature value)[17]
Substrate
Product
Benzyl alcohol
Benzaldehyde
p-Nitrobenzaldehyde
Cyclohexanone
Benzil
4.0
6.0
3.0
3.0
2.5
0.5
0.5
1.0
4.0
4.0
4.0
3.5
100
95
178–180,l (179)
106,s (106)
237 (237)
p-Nitrobenzyl alcohol
Cyclohexanol
Benzoin
—
163 (162)
189 (189)
105 (106)
128 (128)
—
90
154–157,l (156)
93–95,s (95)
100
80
1-Octanol
Iso-propanol
1-Octanal
Acetone
168–170,l (170)
54–56,l (56)
100
100
100
90
p-Hydroxyquinone
Benzaldehyde
p-Benzoquinone
Benzoic acid
115–117,s (116)
121,s (121)
—
—
o-Chlorobenzaldehyde
o-Methylbenzaldehyde
o-Methoxybenzaldehyde
Cinnamic acid
o-Chlorobenzoic acid
o-Methylbenzoic acid
o-Methoxybenzoic acid
Benzoic acid
140–141,s (141)
104–105,s (105)
99–101,s (101)
121,s (121)
85
80
—
—
90
—

1036
S. Patel et al.
bath and are uncorrected. The 2,4-dinitrophenyl hydrazones of aldehydes were
prepared by the standard method.[18] The IR spectra of the products and the
2,4-dinitrophenyl hydrazones were recorded on a Perkin Elmer RX-1 FTIR
spectrometer in KBr disc. The solvents for absorption spectra measurements
were purified by using the standard method[19] and distilled just before use.
The absorption spectra were recorded on a Perkin Elmer Lambda EZ-201
UV-Vis spectrophotometer.
Synthesis of Cetyltrimethylammonium Dichromate
Potassium dichromate (2.94 g, 10.0 mmol) in water (100 ml) was added slowly
to a stirred solution of cetyltrimethylammonium bromide (7.38 g, 20.0 mmol)
in water (100 ml) at room temperature. After 15 min the yellow product was
filtered and washed with water until no Br2 and dichromate were detected,
which gave cetyltrimethylammonium dichromate (7.68 g, 98%), Mp 2128C.
Analysis: C, 58.14; H, 10.65; N, 3.54; Cr, 13.11%. C38H84O7N2Cr2
requires, C, 58.16; H, 10.71; N, 3.57; Cr, 13.26%. IR (in cm21): 771, 879,
933, 1467, 2850, 2921, 3028, 3471. NMR (d) 0.86 (t, 6H), 1.29 (m, 48H),
1.67 (m, 4H) 1.74 (m, 4H), 3.42 (s, 18H), 3.51 (m, 4H).
General Method for Oxidation of Organic Substrate Using CTADC
The organic substrate (0.01 M) was refluxed with CTADC (2.66 g, 3.4 mmol)
in chloroform (20 ml) and the reaction was monitored by spectrophotometer at
590 nm for Cr(111) in a chloroform solution. No further increase in the optical
density indicated the completion of the reaction. The reaction mixture was
concentrated and extracted with ether. Evaporation of ether gave the desired
product.
ACKNOWLEDGMENT
The authors thank UGC and DST, New Delhi, for India, for financial support
through the DRS and FIST programs. SP thanks CSIR for JRF (NET).
REFERENCES
1. Brandstrom, A. Phase transfer catalysis. Adv. Phys. Org. Chem. 1977, 15, 267.
2. Dash, S.; Mishra, B. K. Mn(VII) oxidation using cetyltrimethylammonium
permanganate: Self oxidation of CTAP and oxidation of benzylalcohol. Int. J.
Chem. Kinetics. 1995, 27, 627.

Cetyltrimethylammonium Dichromate
1037
3. Dash, S.; Mishra, B. K. Oxidation of styrylpyridinium dyes by permanganate ion.
Bull. chem. Soc. Japan 1994, 67, 673.
4. Dash, S.; Mishra, B. K. Mn(VII) oxidation using cetyltrimethylammonium
permanganate: Oxidation of alkyl cinnamates. Indian J. Chem. 1997, 36A, 662.
5. Mishra, B. K.; Dash, S.; Nayak, B. B. Oxidation of cis-olefinic double bonds by
cetyltrimethylammonium permanganate. Indian J. Chem. 2001, 40A, 159.
6. Mishra, B. K.; Kuanar, M.; Sharma, A.; Nayak, B. B. Cetyltrimethylammonium
cerium nitrate: A phase transferring oxidant. Indian J. Chem. 2001, 40B, 724.
7. Corey, E. J.; Suggs, J. W. Pyridinium chlorochromate: An efficient reagent for
oxidation of primary and secondary alcohols to carbonyl compounds. Tetrahedron
Lett. 1975, 2647.
8. Corey, E. J.; Boger, D. L. Oxidative cationic cyclization reactions effected by
pyridinium chlorochromate. Tetrahedron Lett. 1978, 2461.
9. Piancatelli, G.; Scettri, A.; D’Auria, M. Pyridinium chlorochromate: A versatile
oxidant in organic synthesis. Synthesis 1982, 245.
10. Guziec, F. S., Jr.; Luzio, F. A. 4-(Dimethylamino) pyridinium chlorochromate, a
new selective reagent for the oxidation of allylic and benzylic alcohol. J. Org.
Chem. 1982, 47, 1787.
11. Roldan, F.; Gonzalez, A.; Palomo, C. Nicotnium dichromate: A new cheap reagent
for high yielding large-scale oxidation of carbohydrates. Carbohydrate Research
1986, 149, 1.
12. Chandrasekhar, S.; Takhi, M.; Mohapatra, S. Tetramethylenediammonium dichro-
mate (TMEDADC): A new selective oxidation reagent. Synth. Commun. 1996,
26, 3947.
13. Rajkumar, G. A.; Arabindoo, B.; Murugesen, V. Quinolium fluorochromate (QFC)
supported on alumina as a selective oxidant for alcohol. Synth. Commun. 1999,
29, 2105.
14. Tajbakhsh, M.; Ghaemi, M.; Sarabi, S.; Ghassemzadeh, M.; Heravi, M. M.
N-Methylpiperidinium chlorochromate adsorbed on alumina:
A new and
selective reagent for the oxidation of benzylic alcohols to their corresponding
carbonyl compounds. Monatsh. Chem. 2000, 131, 1213.
15. Mahjoub, A. R.; Ghammami, S.; Abbasi, A. R.; Hossainian, A. A novel synthesis
of tetramethylammonium trioxyfluorochromate (VI). Indian J. Chem. 2000,
39A, 434.
16. Tajbakhsh, M.; Hosseinzadeh, R.; Niaki, M. Y. Synthesis and application of 2,6-
dicarboxy pyridinium chlorochromate as a new oxidizing reagent for alcohols,
silyl ethers and THP ethers under mild and nonaqueous conditions. J. Chem.
Research (S) 2002, 508.
17. Patel, S.; Panda, M. P.; Kuanar, M.; Mishra, B. K. Alkylation of substituted
benzaldehyde on a solid matrix by using Grignard reagent. Indian J. Chem.
2004, 43B, 1299.
18. Furniss, B. S.; Hannaford, A. J.; Rogers, V.; Smith, P. W. G.; Tatchell, A. R. A Text
Book of Practical Organic Chemisry Including Qualitative Organic Analysis, 4th
ed.; ELBS, Longman, 1978.
19. Riddick, J. A.; Bunger, W. B. Organic Solvents; Wiley Interscience: New York,
1970.