Catalysis Communications
Short Communication
Supported cobalt oxide nanoparticles as efficient catalyst in esterification
and amidation reactions
b
c
Fatemeh Rajabi a,1, , Mojdeh Raessi , Rick A.D. Arancon , Mohammad Reza Saidi b,2, Rafael Luque c
⁎
a
Department of Science, Payame Noor University, P. O. Box: 19395-4697, Tehran, Iran
Department of Chemistry, Sharif University of Technology, P. O. Box 11465-9516, Tehran, Iran
Departamento de Quimica Organica, Universidad de Córdoba, Edificio Marie Curie (C-3), Ctra Nnal IV-A, Km 396, E14014 Cordoba, Spain
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 July 2014
Received in revised form 20 September 2014
Accepted 25 September 2014
Available online 2 October 2014
Co/SBA-15 nanoparticle catalysts (CoNP) were prepared using a commonly adapted synthetic route and then
utilised for esterification and amidation reactions using aromatic and linear chain compounds for the production
of long chain esters and amides. The study shows that the use of CoNP catalysts favours the use of aromatic
reactants with electron donating substituents specifically in the para position. For the amidation reaction, good
to excellent yields were obtained demonstrating tolerance towards differently substituted aromatic compounds.
Overall, the synthesized catalysts proved to be efficient and highly versatile, and recyclable under the
investigated conditions.
Keywords:
Supported Co nanoparticles
SBA-15 catalysts
Esterifications
© 2014 Elsevier B.V. All rights reserved.
Amidations
1. Introduction
separable from the organic phase of the liquid mixture [5]. Another
type of solid catalysts is water-tolerant heterogeneous heteropolyacid
Biodiesel is a form of biofuel mainly composed of long chain methyl
esters. Derived usually from triglycerides, biodiesel is a good substitute
of traditional fossil fuels [1]. Studies have shown that carbon emissions
from biodiesel are significantly lower than that of fossil fuels [2]. Biodie-
sel can be easily derived from renewable sources (such as plants, animal
fat), although because of food security [3] (e.g. food vs fuel), issues on
the cost of separation, and downstream processing, alternative biodiesel
feed stocks and biofuels are currently being explored. The industrially
adapted method for the preparation of biodiesel involves a homoge-
neous base catalysed process which generates soap by-products which
are hard to separate. Downstream processing is even more difficult for
two reasons: 1) the final products should be neutralized to remove
the residual catalyst base, and 2) the soap formed also has surfactant
properties that allow them to adhere to the methyl ester fraction during
liquid–liquid separation [4].
catalysts (Cs2.5H0.5PW12O40) with metals possessing Lewis acidity
which work with free fatty acids at low temperatures [6]. Aside from
heterogeneous acid catalysts, basic metal oxides are also used to kineti-
cally favour the reaction, having been shown to perform the conversion
at much shorter times. An example of a metal-oxide catalyst that is able
to provide yields N90% of methyl esters is alkali-doped metal oxide (CaO
and MgO) [7]. Other innovations for esterification/transesterification
processes include the use of supercritical conditions in order to easily
separate products from reactants [8]. Metal-layered hydroxides have
also been reported for biodiesel synthesis because of their crystalline
structure and surface basicity [9,10]. Efficient enzymatic catalysts have
also been used in both esterifications and transesterification reactions
but sparingly utilised in some cases due to their deactivationat higher
temperatures and difficult separation (only improved in immobilized
biocatalysts— i.e. lipases) [11,12].
Many solid acid catalysts have already been proposed for esterifica-
tion reactions, more specifically for the synthesis of long chain ester
compounds (e.g. biodiesel-like biofuels). Solid acid catalysts include
\SO3H functionalized ionic liquid catalysts for biodiesel conversion of
rapeseed oil. In this study, hexamethylene triamine and butane sulfo-
nates were mixed together to form a zwitterionic catalyst that is easily
The synthesis of amides, on the other hand, is one of the most
fundamental and significant subjects in organic chemistry. Amides
play vital roles in versatile biological systems such as proteins and pep-
tides as well as pharmaceuticals, natural products, material chemistry,
and polymers [13]. Syntheses of amides are traditionally carried out
through the reaction of carboxylic acids [13, 14] and activated carboxyl-
ic acids derivatives such as chlorides [15], anhydrides [16], esters [17]
and acyl azides [18] with amines. Alternative approaches such as the
Staudinger ligation [19], Beckmann rearrangement [20] and the
Schmidt-Abue rearrangement [21] have also been developed. Despite
considerable progress in this area, most procedures suffer from
⁎
Corresponding author.
Tel.: +98 2813336366; fax: +98 2813344081.
Tel.: +98 21 6600 5718; fax: +98 21 6601 2983.
1
2
1566-7367/© 2014 Elsevier B.V. All rights reserved.