FIELD OF THE DISCLOSURE:
The present disclosure relates to a solid nanocrystalline catalyst composition and a process
for its preparation.
BACKGROUND:
Fatty acid amides have been reported in literature (Biermann et al., Effects of fatty acid
derivatives on the ignition quality and coldflow of diesel fuel, J. Am. Oil Chem. Soc., 1995,
72,433-437; Alcantara et al., Catalytic production of biodieselJFom soy-bean oil, usedfrying
oil and tallow, Biomass and Bioenergy, 2000, 18, 515-527; and Stournas et al., Effects of
fatty acid derivatives on the ignition quality and coldflow of diesel fuel, J . Am. Oil Chem.
Soc., 1995, 72,433-437) to enhance the ignition quality and other characteristics of fuels and
hence are capable of being used as multifunctional diesel fuel additives.
Alcantara et al. disclose aminolysis of soybean oil, used wing oil and tallow with diethyl
amine in which the soybean oil reacts with diethyl mine in the presence of sodium
methoxide in a Burton-Coblin autoclave in an atmosphere of nitrogen at 175 "C for 48 hours
(as illustrated in Scheme-1). The fatty acid amide thus obtained was blended with petroleum
diesel fuel to improve its ignition quality. The major drawback of this method is the
separation of the amide from the glycerol by-product.

Scheme-1: Aminolysis of soybean oil with diethyl amine.
Further, the synthesis of fatty acid amide from erucic acid using immobilized lipase
(novozym 435) as a catalyst is reported by Awasthi and Singh (Catalyzed synthesis of f
acid amide (Erucamide) using fatty acid and urea, J. Oleo Sci., 2007, 56,507-509).
Levinson et al. (Lipase catalyzed production of novel hydroxylated fatty amides in organic
solvents, Enz. Microb. Technol., 2005, 37, 126-130) also disclose a process for fatty acid
amide synthesis from ricinoleic acid and ammonia using Pseudozyma (Candida) antarctica
lipase B as a catalyst. The maximum conversion of 95% is obtained when the reaction was
carried out at 55 "C for 1 day.
M.C. de Zoete et al. (Lipase-catalyzed ammonolysis of lipids: A facile synthesis of fatty acid
amides, J. Mol. Catal. B, 1, 1996, 109-1 13 and Journal of Molecular Catalysis B: Enzymatic,
1996, 2, 141-145) disclose the use of Candida antarctica lipase (Novozym 435) as a catalyst
@ for amidation of olive oil to produce nearly pure olearnide with 90% yield after 72 hours of
reaction duration at 60 "C.
Further, the microwave assisted synthesis of fatty acid amides from fatty acids is also
reported (see for example Microwave-assisted facile and convenient synthesis of fatty acid
amide (erucamide), European Journal of Lipid Science and Technology, 2009, 11 1, 202-206
by Awasthi et al.; and A catalytic amidation process for the production of fatty acid amides
by Hoong et al. as disclosed in United Kingdom Patent No. 2415194 and United Kingdom
Patent Application No. 2005 122 1). Hosseini-Sarvari et al. disclose solid acid catalysed
processes of amidation of fatty acids as well as benzoic acids (Nano Sulfated Titania as Solid
Acid Catalyst in Direct Synthesis of Fatty Acid Amides, Journal of Organic Chemistry, 2011,
76,2853-2859).
Industrial scale production of the fatty acid amides is disclosed by Feairheller et al. (A Novel
Technique for the Preparation of Secondary Fatty Amides. III. Alkanolamides, Diamides and
Aralkylamides, J . Am. Oil Chem. Soc., 1994, 71, 863-866) which involve the heating of fatty
acids or fatty methyl esters with ethanolamine at 140-160 "C for 6-12 hours, as illustrated
Scheme-2: Aminolysis of laurel oil with ethanolamine.
In this reaction, mine itself acts as a catalyst. However, when the reaction was catalyzed by
a strong base, for example, sodium methylate or sodium methoxide, the reaction proceeded at
a faster rate and completed within 3 and 1 hour, respectively (see Continuous High
Temperature Preparation of Alkylolamides, Ibid., 1962, 39, 2 13-2 15 by J.A. Monick and
Kolancilar; and Preparation of Laurel Oil AlkanolamideJi.om Laurel Oil, J. Am. Oil Chem.
Soc., 2004, 81, 597-598 by H. Kolancila).
The hitherto disclosed methods for the preparation of fatty acid amides and their derivatives
involve the use of either no catalyst or homogeneous catalysts. In the former case though the
complete conversion of substrate to fatty acid amides or their derivatives is achieved, it
requires relatively long reaction hours and relatively high reaction temperature. In the latter
case, in addition to incomplete conversion, the fatty acid amides are found to be contaminated
with catalyst residues. Thus product purification is essential, which requires plenty of water
and leads to the generation of huge amounts of industrial effluents.
Transesterification of triglycerides is another important organic transformation for producing
fatty acid methyl esters (FAMEs), commonly known as biodiesel. Transesterification of
triglycerides (vegetable oil or animal fat) with methanol in the presence of a catalyst
(chemical or biological) leads to the formation of fatty acid methyl esters (FAMEs) and
glycerol as a by-product.
Homogenous base catalysts such as hydroxides and methoxides of sodium or potassium are
frequently used for transesterification reaction on industrial scale (see for example Ma and
Hanna, Biodiesel production: a review, Bioresour. Technol., 1999, 70, 1-15). The use of
these catalysts is however allied with several disadvantages such as formation of biodiesel
and glycerol contaminated with sodium or potassium ions, production of soap instead of
biodiesel and deactivation of catalysts if moisture andlor free fatty acids (FFAs) content in
feedstock are > 0.3 and/or > 0.5 wt%, respectively (as disclosed by M.J. Haas, The interplay
between feedstock quality and esterijication technology in biodiesel production, Lipid
Technol., 2004, 16, 7-1 1 and Canakci and Gerpen, Biodiesel production via acid catalysis,
Trans. ASAE, 1999,42, 1203-1210).
Thus, the use of homogeneous catalysts requires costly refined vegetable oils which comprise
relatively lesser contents of moisture and free fatty acids. The use of expensive refined
vegetable oils thus leads to an increased cost of bio-diesel production and also results in fuel
vs food controversy. In spite of several advantages over conventional diesel fuel, biodiesel
could not get the desired commercial success in many countries due to the non availability of
adequate feedstock.
The problems allied with the use of expensive refined vegetable oils could be resolved by
employing non-edible oils (for example, karanja oil (obtained from seeds of Millettia
pinnata) and jatropha oil (obtained from seeds of Jatropha curcas)), animal fats or waste
cooking oils as a feedstock for biodiesel production (see for example, Maddikeri et al.,
IntensiJication Approaches for Biodiesel Synthesis from Waste Cooking Oil: a Review, Ind.
Eng. Chem. Res., 2012, 51, 14610-14628; Deshrnane et al., Ultrasound-Assisted Synthesis of
Biodiesel from Palm Fatty Acid Distillate, Ind. Eng. Chem. Res, 2009, 48, 7923-7927; Gole
and Gogate, IntensiJication of Synthesis of Biodiesel from Nonedible Oils Using
Sonochemical Reactors, Ind. Eng. Chem. Res.2012, 5 1, 1 1866-1 1874 and Hingu et al.,
Synthesis of biodiesel from waste cooking oil using sonochemical reactors, Ultrason.
Sonochem., 2010,17,827-832).
The use of less expensive non-edible oils, animal fats or waste cooking oils have the
potential to reduce the overall biodiesel production cost. As these oils usually contain high
FFAs (up to 12 wt%) and moisture content (- 3 wt%), the use of a homogeneous base
catalyst is not suitable for their transesterification.
In order to circumvent the above described problems allied with the application of low
quality feedstock for biodiesel production, several efforts have been made for the
development of heterogeneous catalysts (for example, Demirbas, Progress and recent trends
in biofuels, Prog. Energy Combust. Sci., 2007, 33, 1-18; Kumar and Ali, Nanocrystalline
Lithium Ion Impregnated Calcium Oxide As Heterogeneous Catalyst for Transesterzj?cation
of High Moisture Containing Cotton Seed Oil, Energy Fuels, 2010,24,2091-2097).
Heterogeneous catalysts have several advantages over homogeneous catalysts including,
easier catalyst operation and separation, recyclability, and high moisture and FFAs content
resistance.
A commercial biodiesel plant based on EsterfipH technology has been set up by the French
Institute of Petroleum (IFP) that employs mixed oxides of Zn and A1 as a heterogeneous
catalyst for the transesterification of triglycerides (Serio et al., Heterogeneous Catalysts for
Biodiesel Production, Energy Fuels, 2008, 22, 207-217). This technology does not require
catalyst recovery and biodiesel washing with water and provides around > 98% biodiesel
yield. However, the relatively low catalyst activity under moderate reaction conditions,
demands high reaction temperature (200-250 "C) and high pressure to obtain the specified
yield of FAMEs.
Therefore, there is felt a need to provide a catalyst composition which successfully obviates
the above described and other disadvantages of the prior-art related with the production of
fatty acid amides and fatty acid methyl esters.
OBJECTS:
Some of the objects of the present disclosure are described herein below:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or
to at least provide a useful alternative.
Another object of the present disclosure is to provide a catalyst composition useful for the
production of fatty acid alkyl esters and fatty acid amides from a variety of low quality and
cheap feedstock such as vegetable oils and animal fats.
Still another object of the present disclosure is to provide a catalyst composition useful for
the production of fatty acid alkyl esters and fatty acid amides, which is re-usable successively
several times.
Yet another object of the present disclosure is to provide a process for preparing a solid
catalyst composition useful for the production of fatty acid alkyl esters and fatty acid amides,
wherein the process is very simple, economical and energy efficient.
A further object of the present disclosure is to provide a process for producing fatty acid alkyl
esters and fatty acid amides from low quality and relatively cheaper feedstock such as nonedible
vegetable oils, animal fats or waste cooking oils by using the catalyst composition of
the present disclosure.
Other objects and advantages of the present invention will be more apparent from the
following description when read in conjunction with the accompanying figures, which are not
intended to limit the scope of the present invention.
SUMMARY:
In accordance with the present disclosure, there is provided a solid nanocrystalline catalyst
composition comprising solid calcium oxide dispersed with at least one catalytically active
metal, in an oxidized form, selected from the group consisting of manganese, iron, cobalt,
nickel, copper and zinc, said active metal being present in an amount of 0.25 to 10 wt% of the
calcium oxide mass.
Typically, the catalytically active metal is Nickel.
In accordance with the present disclosure there is provided a process for preparing a solid
nanocrystalline catalyst composition, said process comprising the following steps:
(i) preparing calcium oxide slurry having a pre-determined concentration;
(ii) adding to the slurry, a pre-determined weight proportion of an aqueous solution
of an active metal precursor of pre-determined concentration;
(iii) stirring the resultant slurry for a time period of 1 to 5 hours at 30-35 "C,
preferably for 3 hours at room temperature; and
(iv) air drying and calcining the resultant slurry at a temperature in the range of 150
to 950 O C for a time period of 12 hours to obtain a solid catalyst composition.
Typically, the active metal precursor includes at least one metal precursor selected from the
group consisting of nickel nitrate, nickel sulphate, nickel carbonate, nickel chloride, ferric
nitrate, ferric sulphate, ferric carbonate, ferric chloride, cobalt nitrate, cobalt sulphate, cobalt
carbonate, cobalt chloride, copper nitrate, copper sulphate, copper carbonate, copper chloride,
zinc nitrate, zinc sulphate, zinc carbonate and zinc chloride.
Typically, the aqueous solution of the active metal precursor is added in an amount sufficient
for obtaining the catalyst composition comprising active metals in an amount of 0.25 to 10
wt% of the calcium oxide mass.
In accordance with the present disclosure, there is provided a process for preparing fatty acid
esters and fatty acid amides from triglycerides by using the catalyst composition of the
present disclosure, said process comprises reacting a triglyceride feedstock in the presence of
the catalyst composition of the present disclosure individually with a transesterification
reagent and an aminolysis reagent under the reaction conditions of temperature varying from
35 to 75 OC, catalyst amount varying from 1 to 15 wt% and reagent to triglyceride feedstock
molar ratio of 3: 1 to 18: 1.
Typically, the transesterification reagent includes at least one alcohol selected fiom the group
consisting of methanol, ethanol, 1 -propanol, 1 -butanol, 1 -pentanol, 1 -hexanol, 1 -heptanol, 1 -
octanol, 1 -nonanol, 1 -decanol and 1 -undecanol.
Typically, the molar ratio of the transesterification reagent to the triglyceride feedstock varies
from 3 : 1 to 18: 1, preferably 9: 1.
Typically, the aminolysis reagent includes at least one reagent selected from the group
consisting of diethanolamine, ethanolamine, dimethanolamine, methanolamine and the like.
Typically, the molar ratio of the aminolysis reagent to the triglyceride feedstock varies from
3:l to 7:1, preferably 5:l.
Typically, the catalyst is added in an amount of 5 wt% with respect to total mass of the
triglyceride feedstock.
Typically, the triglyceride feedstock includes vegetable oils and animal fats selected from the
group consisting of soybean oil, mutton fat, virgin cotton seed oil, used cotton seed oil, castor
oil, karanja oil and Jatropha oil.
BRIEF DESCRIPTION OF THE ACCOMPNAYING DRAWINGS:
Figure 1 of the accompanying drawings in accordance with the present disclosure illustrates
XRD spectra of commerciaily available CaO, CaO doped with 0.5 wt% of nickel under
calcination temperature of 150 to 900 OC wherein * = calcium oxide; + = calcium hydroxide;
and = calcium carbonate;
Figure 2 of the accompanying drawings in accordance with the present disclosure illustrates
XRD spectra of commercially available CaO, CaO doped with 1-6 wt% of nickel wherein * =
Calcium oxide; a = nickel oxide; and = calcium carbonate;
Figure 3 of the accompanying drawings in accordance with the present disclosure illustrates
(a) SEM and (b) TEM images of the solid nanocrystalline catalyst composition of example-1 ;
Figure 4 of the accompanying drawings in accordance with the present disclosure illustrates
FT-IR spectra of (a) used cotton seed oil and (b) fatty acid amide derived from used cotton
seed oil;
Figure 5 of the accompanying drawings in accordance with the present disclosure illustrates
1 H-NMR spectra of (a) cotton seed oil and (b) cotton seed oil derived fatty acid amide; and
Figure 6 of the accompanying drawings in accordance with the present disclosure illustrates
1 H-NMR spectra of (a) cotton seed oil, (b) cotton seed oil derived fatty acid methyl ester.
DETAILED DESCRIPTION:
The description herein after and the specific embodiments will so fully reveal the general
nature of the embodiments herein that others can, by applying current knowledge, readily
modify and/or adapt for various applications such specific embodiments without departing
from the generic concept, and therefore, such adaptations and modifications should and are
intended to be comprehended within the meaning and range of equivalents of the disclosed
embodiments. It is to be understood that the phraseology or terminology employed herein is
for the purpose of description and not of limitation. Therefore, while the embodiments herein
have been described in terms of preferred embodiments, those skilled in the art will recognize
that the embodiments herein can be practiced with modification within the spirit and scope of
the embodiments as described herein.
The present disclosure overcomes the disadvantages allied with the commercial production of
fatty acid amides and fatty acid alkyl esters by providing a solid nanocrystalline catalyst
composition which successfully catalyzes transesterification and aminolysis of a variety of
low value triglycerides feedstock. Also, despite using low value triglycerides, the solid
nanocrystalline catalyst composition of the present disclosure provides fatty acid amides and
fatty acid alkyl esters of high purity and with enhanced yield.
In accordance with the present disclosure, there is provided a solid nanocrystalline catalyst
composition comprising a solid calcium oxide support dispersed with at least one
catalytically active metal, in an oxidized form, selected from 3d-transition elements wherein
the catalytically active metal is present in an amount of 0.5-10 wt% with respect to the CaO
mass.
The 3d-transition elements useful for the purpose of the preset disclosure include at least
element selected from the group consisting of nickel, zinc, copper, manganese, iron and
cobalt.
The solid catalyst composition in accordance with the present disclosure may be prepared by
any chemical methods known in the prior-art for impregnating active metals on a solid
inorganic oxide support, such as wet impregnation, precipitation, co-precipitation, sol-gel,
hydrothermal synthesis and the like. The solid nanocrystalline catalyst composition of the
present disclosure is prepared by wet-impregnation method. The wet impregnation method
for preparing the solid nanocrystalline catalyst composition of the present disclosure
comprises the method steps of preparing a calcium oxide slurry; preparing an aqueous
solution of an active metal precursor; and treating the calcium oxide slurry with the aqueous
solution of an active metal precursor under pre-determined conditions of time and
temperature to obtain the nanocrystalline catalyst composition of the present disclosure.
A pre-determined weight proportion of calcium oxide (CaO) is suspended in a predetermined
amount of deionized water under continuous stirring to obtain the calcium oxide
slurry. An aqueous solution of an active metal precursor of a pre-determined concentration is
then added to the calcium oxide slurry under continuous stirring.
Examples of active metal precursors suitable for the process of the present disclosure
includes at least one salt selected from the group consisting of nickel nitrate, nickel sulphate,
nickel carbonate, nickel chloride, ferric nitrate, ferric sulphate, ferric carbonate, ferric
chloride, cobalt nitrate, cobalt sulphate, cobalt carbonate, cobalt chloride, copper nitrate,
copper sulphate, copper carbonate, copper chloride, zinc nitrate, zinc sulphate, zinc carbonate
and zinc chloride. The aqueous solution of the active metal precursor is typically added to the
calcium oxide slurry in an amount sufficient for obtaining the solid nanocrystalline catalyst
composition having 0.25 to 10 wt % of the active metal dispersed in calcium oxide. The
inventors of the present disclosure advantageously optimized the amount of catalytically
active metals dispersed in calcium oxide in order to provide a solid nanocrystalline catalyst .
composition with enhanced catalytic efficiency. The preferred weight percentage of the
catalytically active metal dispersed in calcium oxide is 0.5 wt%, as the amount higher and
lower than 0.5 wt% does not show any enhancement in the catalytic efficiency of the catalyst
composition.
The resultant slurry thus obtained is stirred for a time period ranging between 1 to 5 hours at
30-35 "C. In accordance with one of the embodiments of the present disclosure, the resultant
10
slurry is stirred for 3 hours. Subsequently, the resultant slurry is air dried and calcined at a
temperature ranging from 150 to 950 OC for a time period of 12 hours. Similar to the amount
of the catalytically active metal dispersed in calcium oxide, the inventors of the present
disclosure also optimized the calcination temperature for enhanced catalytic efficiency. The
preferred calcination temperature in accordance with the process of the present disclosure is
650 OC.
The solid nanocrystalline catalyst composition obtained in accordance with the process of the
present disclosure is further characterized by powder XRD, BET surface area measurement,
Hammett indicator test, SEM, EDX and TEM techniques. The powder and TEM analysis of
the catalyst composition of the present disclosure supports the formation of nanocrystalline
@ form of the catalyst. The particle size of the solid nanocrystalline catalyst composition of the
present disclosure ranges from 18 to 50 nm.
The solid nanocrystalline catalyst composition in accordance with the present disclosure is
used in a variety of organic transformations including, but not limiting to, the production of
fatty acid alkyl esters and fatty acid amides by transesterification and aminolysis of
triglycerides, respectively.
Still another aspect of the present disclosure provides a process for preparing fatty acid alkyl
esters by transesterification of a triglyceride feedstock by using the solid nanocrystalline
catalyst composition of the present disclosure (referred to as scheme-3)
C H 2 - O C O - R CH2-OH I catalyst
CH-0-CO-R + 3 CH,OH
- I 3 R - C - O C H , + CH-OH
I
CH,-0-CO-R
I
CH,-OH
Vegetable oil Methanol Fatty acid methylester Glycerol
Scheme 3: Transesterification of triglycerides.
Transesterification of the triglyceride feedstock in accordance with the present disclosure
may be carried out by using any conventional method known in the related prior-art. The
method used for transesterification of the triglyceride feedstock in accordance with the
present disclosure comprises the following steps:
The triglyceride feedstock, a transesterification reagent and the catalyst composition of the
present disclosure are admixed together in a pre-determined weight proportion to obtain a
reaction mixture. The obtained reaction mixture is then heated to a temperature varying from
35 to 75 OC until complete conversion of the feedstock to the fatty acid methyl esters is
achieved.
The solid catalyst composition is typically added in an amount varying from 1 to 15 wt% of
the feedstock mass. In accordance with one of the embodiments of the present disclosure, the
solid catalyst composition is added in an amount of 5 wt% of the feedstock mass.
The transesterification reagent useful for transesterification of the triglyceride feedstock in
accordance with the present disclosure is an alcohol. Examples of alcohols suitable for
transesterification of the triglyceride feedstock include at least one alcohol selected from the
group consisting of methanol, ethanol, 1 -propanol, 1 -butanol, 1 -pentanol, 1 -hexanol, 1 -
heptanol, 1 -0ctano1, I -nonanol, 1 -decanol and 1 -undecanol. The alcohol and the triglyceride
feedstock are typically admixed in the molar ratio of 3:l to 18:l. In accordance with one of
the embodiments of the present disclosure, the alcohol and the triglyceride feedstock are
typically admixed in the molar ratio of 9:l. Examples of triglyceride feedstock suitable for
the purpose of the present disclosure include vegetable oils and animal fats selected from the
group consisting of soybean oil, mutton fat, virgin cotton seed oil, used cotton seed oil, castor
oil, karanja oil and Jatropha oil.
The progress of transesterification of the triglyceride feedstock is monitored by subjecting the
samples from the reaction mixture at specified time intervals to proton NMR. After
completion of the transesterification reaction, the reaction mixture is filtered through an
ordinary filter paper and rotary evaporated to recover excess of alcohol and kept in a
separating funnel for a specified time period to separate the lower glycol layer from the upper
fatty acid methyl esters layer. The fatty acid methyl esters are also characterized and
quantified by proton NMR by adopting a procedure as disclosed by G. Knothe, Determining
the blend level of mixtures of biodiesel with conventional diesel fuel by fiber-optic nearinfrared
spectroscopy and 'H nuclear magnetic resonance spectroscopy, J. Am. Oil Chem.
SOC.2, 001,78, 1025-1028.
In still another aspect, the present disclosure provides a process for preparing fatty acid
amides by aminolysis of the triglyceride feedstock (referred to as schemes-4 and 5)
H2C-OCO-R H2C-OH
I ,CH~CH~OH 0.5-NilCa0450 fl /CHCH20H I
HC-0-CO-R + ~HN, - 3R-C-N, + HC-OH
I CH2CH20H 1 10 OC CHCH,OH I
trigly ceride Diethanolamine Fatty acid amide Glycerol
Scheme 4: Aminolysis of triglycerides with diethanolamine in the presence of the solid
nanocrystalline catalyst composition of the present disclosure.
0 CH2CHzOH 0.5-Ni/Ca0650 0
II / 11 /CH2CH20H
R-CPOCH3 + HN, - R - C N + CH30H
CH2CH20H llO°C \CH~CH~OH
Cotton seed oil FAMEs Diethanolamine
or mutton fat FAMEs
or methyl laurate
Fatty acid amide Methanol
Scheme 5: Aminolysis of cotton seed oil fatty acid methyl esters or mutton fat fatty acid
methyl acid esters or methyl laurate with diethanolamine in the presence of the solid
nanocrystalline catalyst composition of the present disclosure.
Aminolysis of the triglycerides feedstock in accordance with the present disclosure may be
carried out by using any conventional method known in the related prior-art. The method for
aminolysis of the triglyceride feedstock in accordance with the present disclosure comprises
the following steps:
@ The triglyceride feedstock, an aminolysis reagent and the solid nanocrystalline catalyst
composition of the present disclosure are admixed together in a pre-determined weight
proportion to obtain a reaction mixture. The solid nanocrystalline catalyst composition is
typically added in an amount varying from 1 to 15 wt% of the feedstock mass. In accordance
with one of the embodiments of the present disclosure, the solid catalyst composition is
added in an amount of 5 wt% of the feedstock mass. The obtained reaction mixture is then
heated at a temperature varying from 35 to 150 OC until complete conversion of the feedstock
to the fatty acid amides is achieved. In accordance with one of the embodiments of the
present disclosure, the obtained reaction mixture is heated at a temperature of 90-1 50 "C.
Examples of aminolysis reagents suitable for aminolysis of the triglyceride feedstock include
at least one reagent selected from the group consisting of diethanolamine, ethanolamine,
13
dimethanolamine, methanolamine and other dialkylamines or monoalkylamines. The molar
ratio of the aminolysis reagent to the triglyceride feedstock varies from 3:l to 7:l. In
accordance with one of the embodiments of the present disclosure, the molar ratio is 5: 1.
Examples of the triglyceride feedstock suitable for the purpose of the present disclosure
includes vegetable oils and animal fats selected from the group consisting of soybean oil,
mutton fat, virgin cotton seed oil, used cotton seed oil, castor oil, karanja oil and Jatropha oil.
In addition to the triglyceride feedstock as herein above described, fatty acid amides can also
be produced by the aminolysis of fatty acid methyl esters derived from the triglyceride
feedstock (referred to as schemed).
The progress of the aminolysis of the triglyceride feedstock is monitored by subjecting the
samples from the reaction mixture at specified time intervals to FT-IR studies. After
completion of the aminolysis reaction, the reaction mixture is filtered through an ordinary
filter paper and dissolved in an organic solvent, for example, hexane and placed in a
separating funnel. The upper hexane layer is separated from the lower glycerol layer, washed
with water and dried over sodium sulfate and subsequently rotary evaporated to yield pure
fatty acid amides.
The solid nanocrystalline catalyst composition of the present disclosure shows better catalytic
activity. Further, the reusability of the catalyst composition of the present disclosure is also
tested. The solid catalyst composition of the present disclosure catalyzes at least seven
successive cycles for the complete aminolysis and transesterification of the triglyceride
feedstock. e
Throughout this specification the word "comprise", or variations such as "comprises" or
"comprising", will be understood to imply the inclusion of a stated element, integer or step,
or group of elements, integers or steps, but not the exclusion of any other element, integer or
step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements
or ingredients or quantities, as the use may be in the embodiment of the invention to achieve
one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been
included in this specification is solely for the purpose of providing a context for the
invention. It is not to be taken as an admission that any or all of these matters form part of the
prior art base or were common general knowledge in the field relevant to the invention as it
existed anywhere before the priority date of this application.
The embodiments herein and the various features and advantageous details thereof are
explained with reference to the non-limiting embodiments in the following description.
Descriptions of well-known components and processing techniques are omitted so as to not
unnecessarily obscure the embodiments herein. The examples used herein are intended
merely to facilitate an understanding of ways in which the embodiments herein may be
practiced and to further enable those of skill in the art to practice the embodiments herein.
Accordingly, the examples should not be construed as limiting the scope of the embodiments
herein. a
The solid nanocrystalline catalyst compositions of Table-1 were prepared by a wet chemical
method as follows:
10 g CaO was suspended in 40 ml deionized water. To the prepared CaO slurry, 10 ml
aqueous solution of nickel nitrate was added. The aqueous solution of nickel nitrate having
concentration in the range of 0.12 to 3.5 % concentration (wlv) was used so as to obtain the
solid nanocrystalline catalyst compositions having 0.25 to 7 wt % of Ni (11) in CaO. The
resultant slurry thus obtained was stirred for 3 hours and subsequently air dried and calcined
at a temperature of 650 "C for 12 hours.
In this example, the solid nanocrystalline catalyst composition is prepared by a process
similar to example-1, except that the calcination temperature was varied from 150 "C to 950
The solid nanocrystalline catalyst compositions prepared by the process of example-1 and
example-2 were characterized by using various physicochemical techniques such as powder
XRD, BET surface area measurement, a Hammett indicator test, Scanning Electron
Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Transmission
Electron Microscopy (TEM).
The structural analysis of the solid nanocrystalline catalyst compositions, prepared by
example-1 and example-:! was performed by powder XRD analysis. The powder XRD
patterns of commercially available CaO, the catalyst compositions of example-1 and
example-2 are shown in Figure 1 of the accompanying drawings. The commercial CaO
showed peaks at 28 values of 37.36", 54.36" and 32.57" due to the presence of calcium oxide
in cubic form (JCPDS card no. 821691). The presence of low intensity peaks at 29.4" and at
64.4" reveals the presence of minor amounts of calcium carbonate as calcite in the CaO used
as a support (JCPDS 881 81 1). The presence of peaks at 34.1Z0, 18.06' and 47.1 5" in the
powder XRD pattern of the catalyst composition of example-2 calcined at 150 OC and 350 "C
temperature supports the existence of Ca(OH)2 in hexagonal form (JCPDS 841275). The
XRD pattern of the catalyst composition of example 2 calcined at 450 "C, shows the peaks at
28 - 34.1Z0, 18.06", 47.15" due to the presence Ca(OH)2 and at 28 - 37.36", 54.36", 32.57"
due to the CaO in cubic phase. Hence, the transition of Ca(OH)2 to CaO starts at 450 "C and
complete conversion of Ca(OH)2 into CaO occurs at 650 "C. The absence of diffraction
patterns corresponding to Ni(N03)2 or NiO is due to their high degree of dispersion on the
CaO surface.
The XRD pattern of the solid nanocrystalline catalyst compositions of example-1 revealed
that as long as nickel loading was 5 5 wt%, no peaks corresponding to NiO were observed in
powder XRD patterns of the solid catalyst composition. The same could be attributed to the
high degree of dispersion of nickel ions on the CaO surface, as long as Ni concentration in
CaO was less than 5 wt%. However, when the nickel concentration was increased upto 6
wt%, low intensity peaks at 28 values of 43.2" and 62.7" were observed due to the presence
of NiO in cubic phase (JCPDS 780643) as shown in Figure 2 of the accompanying
drawings. Hence, a maximum of 5 wt% Ni could be dispersed in CaO without affecting the
regular structure of the latter.
The particle size of the solid nanocrystalline catalyst compositions of examples 1 was
determined by Debye-Scherrer method (Qadri et al., 1999) using powder XRD data and was
found to be in the range of 17 to 50 nrn. The results are shown in Table-1 .The basic strength
of the solid nanocrystalline catalyst compositions of example-1 is also shown in Table-1 .
Table-1: Effect of Ni2+ concentration on the basic strength and particle size of catalyst
compositions of example-1 .
16
It is evident from Table-1, that the basic strength of the pure calcium oxide (CaO) was found
to increase from 9.80.5 wt%)
does not have any impact on the reaction rate. Therefore, 0.5 wt% of ~ iion~ con+cen tration
dispersed on the calcium oxide support was found to be optimum for the better activity of the
solid nanocrystalline catalyst composition of example- 1.
Exampled:
This example describes a process for preparing fatty acid methyl esters by transesterification
@ of waste cooking oil using the catalyst composition of example-1 at the optimized reaction
conditions of catalyst amount, reaction temperature and alcohol to feedstock molar ratio.
A 100 ml two necked round bottom flask equipped with a water-cooled condenser, oil bath
and a magnetic stirrer was charged with 10 g of used cotton seed oil. Subsequently, 3.1 ml of
methanol (methanol to used cotton seed oil ratio: 9:l (dm) and the catalyst composition of
example-1 in an amount of 5 wt% of the oil were charged. The reaction mixture thus obtained
was heated to an optimized temperature of 65 OC for a specific time period. The progress of
the transesterification reaction was monitored from time to time. For this, samples from the
reaction mixture were withdrawn after every fifteen minutes with the help of a glass dropper,
centrifuged and subjected to proton NMR studies to calculate the yield of fatty acid methyl
esters (FAMEs). Results are provided in Table-3.
After completion of the reaction, the reaction mixture was filtered through an ordinary filter
paper and rotary evaporated in order to recover excess methanol and finally kept in a
separating funnel for 12 h to separate the lower glycerol layer from the upper FAMEs layer.
FAMEs thus obtained were characterized and quantified by 'H-NMR by following the
procedure disclosed by G. Knothe, Determining the blend level of mixtures of biodiesel with
conventional diesel fuel by fiber-optic near-infiared spectroscopy and 'H nuclear magnetic
resonance spectroscopy, J. Am. Oil Chem. Soc, 2001,78, 1025-1028, as given below:
Yield = {21(methoxy)/31(methylene)} 100
where I(methoxy) and I(methylenaere) the areas of the methoxy and methylene protons,
respectively, in 'H NMR spectra of FAMEs.
19
1 a
Methyl esters of waste cooking oil: 'H-NMR (CDC13, 6 ppm): 5.34 (m, -CH=CH-), 3.6 (s, -
OCH3), 2.77 (m, -CH=CH-CH2-CH=CH-), 2.3 (m, -CH2-CO-), 2.03 (m, -CH2-(CH2),-), 1.6-
1.25 (m, -(CH2),- ), 0.88 (m, -CH2-CH3);' 3 ~(CD-C13,~ 6 pp~m): ~174.0 9 (-CO-CH2-),
129.9 (-CH=CH-),77.1 (CDC13), 5 1.2 (-OCH3), 34.1 (-CO-CH2-), 3 1.9 (03 -CH2-), 29.66-
29.08 (-CH=CH-CH2-, -CH2-), 27.2 (-CH=CH-CH2-CH=CH-), 25.6-24.80 (40-CH2-
CH2-), 22.70,22.47 (02 -CH2-) and 14.16 (01 -CH3).
Similar patterns were observed in the proton NMR spectrum of the FAMEs obtained from
transesterification of other feedstock.
Table-3: Effect of nickel ion concentration on transesterification activity of the catalyst
compositions of examples-1 .
Reactions conditions: methanol: used cotton seed oil = 9:l (mlm), catalyst amount = 5wt%
of the used cotton seed oil, temperature=65 OC; transesterification was carried out for 6 hours.
It is evident from table-3, that with the increase in the nickel ion concentration from 0 to 0.5
wt%, rate of transesterification increased. However, further increase in Ni ion concentration
(>0.5 wt%) does not have any impact on the reaction rate.
Exampled:
This example describes the effect of moisture content on transesterification of used cotton
P L
seed oil.
Presence of > 0.3 wt% moisture in feedstock, leads to the formation of soap instead of
biodiesel in the presence of a homogenous catalyst. The used cotton seed oil used in the
present study was found to have 0.3 wt % moisture content. Transesterification of the used
cotton seed oil using NaOH or KOH as a homogeneous catalyst leads to a saponification
reaction. However, the same reaction when catalyzed by the nanocrystalline catalyst
compositions of example-1 (the solid nanocrystalline catalyst composition having 0.5 wt% of
Ni in CaO was used) resulted in complete conversion of oil into biodiesel.
In order to determine the maximum moisture resistance of the solid catalyst composition of
example-1, transesterification of used cotton seed oil was performed in the presence of 0.4-
3.4 wt% (waterloil) water. The catalyst was found to be effective for complete
transesterification of cotton seed oil in 1.75 h even when 3.4 wt% of moisture content was
present in the reaction mixture as shown in Table 4. A further addition of water (> 3.4 wt%)
in the reaction mixture leads to the formation of soap instead of biodiesel.
Table 4: Effect of the moisture content on the time required for complete transesterification
of used cotton seed oil into biodiesel carried out in the presence of the solid catalyst
composition of example-1 .
Reaction conditions: methanol: waste cooking oil ratio = 9:l (mlm), catalyst amount = 5
wt% of the waste cooking oil (catalyst having 0.5 wt% of Ni in CaO mass), temperature = 65
"C.
Example-6:
This example describes the effect of free fatty acid content (FFA) on the transesterification
and the aminolysis activity of catalyst compositions of example-1.
Reaction time (h)
0.5
0.75
1
1.5
Incomplete
conversion
S.
No.
1.
2.
3.
4.
5.
Moisture
content (wt% of
oil)
0.4
1.4
2.4
3.4
4.4
In order to determine the maximum FFA tolerance of the prepared catalyst, a series of
transesterification reactions and aminolysis reactions were performed with a variety of
naturally occurring feedstocks having different amounts of FFAs (wt%) viz., mutton fat (0.9),
virgin soybean oil (0.2), virgin cotton seed oil (0.1 I), castor oil (1.8), used cotton seed oil
(1.8), karanja oil (4.2) and jatropha oil (8.4). The solid nanocrystalline catalyst composition
of example-1 having 0.5 wt% of Ni in CaO was used. As shown in Table 5 and Table-6, the
catalyst was found to be effective for the complete transesterification and the complete
aminolysis of feedstock having upto 8.4 wt% of FFAs. However, relatively lower catalytic
activity of the solid catalyst composition of example-1 towards the transesterification and the
aminolysis of karanja and jatropha oil was attributed to the fact that partial deactivation of the
catalyst occurs by higher concentration of FFAs present in these oils.
Table 5: Effect of FFAs on the time required for complete transesterification of a variety of
feedstock.
Reaction conditions: methanol: feedstock = 9: 1 (dm), catalyst amount = 5 wt% of feedstock
(catalyst having 0.5 wt% of Ni in CaO mass), temperature = 65 "C.
Table 6: Effect of FFAs on the time required for complete aminolysis of a variety of
feedstock.
Feedstock
Methvl Laurate 98 * 2 %, d m ) transesterification of used cotton
seed oil for five catalytic cycles as shown in Table 8.
However, the reaction time increases gradually after every successive run in both the cases,
indicating that there is a gradual loss of the activity. The decrease in catalytic activity after
every cycle could be due to partial leaching of nickel from the calcium oxide support or due
to partial deactivation of the catalytic sites.
Table 8: Reusability studies of the catalyst towards transesterification of the used cotton seed
oil.
Reaction conditions: methanol: used cotton seed oil = 9: 1 (mlm), catalyst amount = 5 wt% of
used cotton seed oil, temperature = 65 "C.
TECHNICAL ADVANCEMENTS:
The present disclosure related to a solid nanocrystalline catalyst composition and a process
for its preparation, has the following technical advancements:
The solid nanocrystalline catalyst composition comprising calcium oxide doped with
nickel element is efficient for the complete aminolysis of triglyceride feedstocks even
at room temperature, thereby reducing the energy demand,
The solid nanocrystalline catalyst composition is also very useful for the production
of fatty acid esters commonly known as biodiesel by transesterification of a variety of
feedstock, such as, used cotton seed oil, virgin cotton seed oil, jatropha oil, karanja
oil, soybean oil, castor oil, mutton fat and the like,
The solid nanocrystalline catalyst composition is effective even in the presence of
Free Fatty acids (FFAs) in an amount upto 8.4 wt% and 0.4 wt% moisture content,
The solid nanocrystalline catalyst composition can be successfully reused several
times and each time it provides around 99 % conversion of the triglyceride feedstock
during the transesterification and aminolysis thereof.
The numerical values mentioned for the various physical parameters, dimensions or
quantities are only approximations and it is envisaged that the values higherllower than the
numerical values assigned to the parameters, dimensions or quantities fall within the scope of
the invention, unless there is a statement in the specification specific to the contrary.
@ The foregoing description of the specific embodiments will so fully reveal the general nature
of the embodiments herein that others can, by applying current knowledge, readily modify
and/or adapt for various applications such specific embodiments without departing from the
generic concept, and, therefore, such adaptations and modifications should and are intended
to be comprehended within the meaning and range of equivalents of the disclosed
embodiments. It is to be understood that the phraseology or terminology employed herein is
for the purpose of description and not of limitation. Therefore, while the embodiments herein
have been described in terms of preferred embodiments, those skilled in the art will recognize
that the embodiments herein can be practiced with modification within the spirit and scope of
the embodiments as described herein.

1 We Claim:
1. A solid nanocrystalline catalyst composition comprising solid calcium oxide dispersed
with at least one catalytically active metal, in an oxidized form, selected from the group
consisting of manganese, iron, cobalt, nickel, copper and zinc, said active metal being present
in an amount of 0.25 to 10 wt% of the calcium oxide mass.
I 2. The catalyst composition as claimed in claim 1, wherein the catalytically active metal is
Nickel.
3. A process for preparing a solid nanocrystalline catalyst composition, said process
comprising the following steps:
(i) preparing calcium oxide slurry having a pre-determined concentration;
(ii) adding to the slurry, a pre-determined weight proportion of an aqueous solution
of an active metal precursor of pre-determined concentration;
(iii) stirring the resultant slurry for a time period of 1 to 5 hours at 30-35 "C,
preferably for 3 hours at room temperature; and
(iv) air drying and calcining the resultant slurry at a temperature in the range of 150
to 950 OC for a time period of 12 hours to obtain a solid catalyst composition.
4. The process as claimed in claim 3, wherein the active metal precursor includes at least one
metal precursor selected from the group consisting of nickel nitrate, nickel sulphate, nickel
carbonate, nickel chloride, ferric nitrate, ferric sulphate, ferric carbonate, ferric chloride,
cobalt nitrate, cobalt sulphate, cobalt carbonate, cobalt chloride, copper nitrate, copper
sulphate, copper carbonate, copper chloride, zinc nitrate, zinc sulphate, zinc carbonate and
zinc chloride.
5. The process as claimed in claim 3, wherein the aqueous solution of the active metal
precursor is added in an amount sufficient for obtaining the catalyst composition comprising
active metals in an amount of 0.25 to 10 wt% of the calcium oxide mass.
6. A process for preparing fatty acid alkyl esters and fatty acid amides from triglycerides by
using the catalyst composition of claim-1, said process comprises reacting a triglyceride
feedstock in the presence of the catalyst composition of claim-1 individually with a
transesterification reagent and an aminolysis reagent under the reaction conditions of
temperature varying from 35 to 75 "C, catalyst amount varying from 1 to 15 wt% and regent
to triglyceride feedstock molar ratio of 3 : 1 to 18: 1. 1 ,;; ~ 0 1
7. The process as claimed claim in claim 6, wherein the transesterification reagent is alcohol
selected from the group consisting of methanol, ethanol, 1 -propanol, 1 -butanol, 1 -pentanol, 1 -
hexanol, 1 -heptanol, 1 -0ctano1, 1 -nonanol, 1 -decanol and 1 -undecanol.
8. The process as claimed in claim 6, wherein the molar ratio of the alcohol to the triglyceride
feedstock is 9: 1.
9. The process as claimed in claim 6, wherein the aminolysis reagent includes at least one
reagent selected from the group consisting of diethanolamine, ethanolamine,
dimethanolamine, methanolamine and the like.
10. The process as claimed in claim 6, wherein the molar ratio of the aminolysis reagent to
the triglyceride feedstock varies from 3: 1 to 7: 1, preferably 5: 1.
11. The process as claimed in claim 6, wherein the catalyst is added in the amount of 5 % by
weight of the triglyceride feedstock mass.
12. The process as claimed in claim 6, wherein the triglyceride feedstock includes vegetable
oils and animal fats selected from the group consisting of soybean oil, mutton fat, virgin
cotton seed oil, used cotton seed oil, castor oil, karanja oil and Jatropha oil.