Vol.3, No.7, 530-534 (2011) Natural Science
Copyright © 2011 SciRes. OPEN ACCESS
Hydrolysis—Hydrogenation of soybean oil and tallow
Gisel Chenard Díaz1, Rodolfo Salazar Perez1, Neyda de la Caridad Om Tapanes2, Donato
Alexandre Gomes Aranda1, Angel Almarales Arceo1
1GREENTEC Laboratory, Escola de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil;
*Corresponding Author: gisemarina@yahoo.es
2Department of Industrial Production, State University of the West in Brazil, Rio de Janeiro, Brazil;
*Corresponding Author:neydatapanes@uezo.rj.gov.br
Received 12 March 2011; revised 15 April 2011; accepted 25 April 2011.
Hydrolysis reactions are of major importance to
the oleochemical industry in the production of
fatty acid and their derivates. Hydrolysis of trig-
lyceride from vegetable oil has been studied
under various parameters such as: heteroge-
neous catalyst, temperature, reaction time and
agitation speed. During the hydrolysis of soy-
bean oil and tallow using nickel catalysts on
alumina support was verified that the glycerol
produced worked as hydrogen donor, allowing
the hydrogenation of unsaturated fatty acids
produced. Maximum conversion was achieved
in 3 hours, catalysts 25% NiO/Al2O3, temperature
of 250°C and 270°C and 250 rpm.
Keywords: Hydrolysis; Soybean Oil; Tallow;
Hydrogenation; Saturated Fatty Acid; Selectivity
Vegetable oils are composed by triglycerides. Every
triglyceride, or fat, contains three fatty acid chains attach
to a single glycerol molecule. These fatty acid chains can
be classified as saturated, monounsaturated and polyun-
saturated, depending on the type of chemical bonds pre-
sent. The hydrolysis of triglycerides produces fatty acids
and glycerol [1-4]. Saturated fatty acids have high rele-
vance in the food and oleochemical industries.
The glycerol can be used for hydrogen production by
catalytic reforming reaction using nickel or platinum
catalysts supported on alumina and silica [5].
This paper presents studies and results on producing
saturated fatty acid trough catalytic hydrolysis of soy-
bean oil and tallow. The catalysts used in the heteroge-
neous reactions were nickel supported on gamma alu-
mina, synthesized by the method of wet impregnation.
The reaction is shown in Figure 1.
2.1. Reactants and Preparation of Catalysts
The raw materials used in this study are soybean oil
and tallow. The fatty acid profile of soybean oil and tal-
low are shown in Table 1.
The catalysts used in the heterogeneous reactions
were nickel supported on gamma alumina (5% NiO/
Al2O3, 10% NiO/Al2O3 and 25% NiO/Al2O3). To prepare
the catalyst of nickel supported on alumina was used as
metallic precursor a nickel nitrate salt (Ni(NO3)2.6H2O)
97.0% purity). A commercial alumina (100% purity) was
used as a catalyst support. In each experiment, 5, 10 and
25% of metal was loaded on alumina using wet impreg-
nation method.
Catalyst Characterization
The synthesized catalysts were characterized by tex-
tural analysis techniques, X-ray diffraction (DRX) and
X-ray fluorescence spectrometry (XRF).
Samples were analyzed using a commercial XRF in-
strument. The chemical compositions of Ni/Al2O3 cata-
lysts were measured and the results confirmed the cer-
tain amount of active metals on catalyst supports (Table
Surface areas of catalysts were determined by apply-
ing the Brunauer-Emmett-Teller method (BET), for N2
physisorption at liquid nitrogen temperature (77 K). The
pore volume and average pore diameter were calculated
applying the Barrett-Joyner-Halenda (BJH) method [6].
Table 3 shows the results.
This area reduction is possibly due to partial pores
blockage of the support by the particles of nickel oxide
[7].The calcined catalysts displayed an isotherm of type
IV with H3-type hysteresis.
XRD patterns of the catalysts displays two crystalline
phases, one related to γ-alumina with amorphous struc-
ture characteristic (JCPDS 49-0063) and the other the
bunsenite NiO with cubic structure and space group
Fm3m (JCPDS 47-1049). In the case of catalyst 5% NiO
G. C. Díaz et al. / Natural Science 3 (2011) 530-534
Copyright © 2011 SciRes. OPEN ACCESS
Figure 1. Hydrolysis and hydrogenation of triglycerides.
Table 1. Fatty acid profile of raw materials.
Fatty acid profile Soybean oil Content %
Tallow Content %
Myristic (C14:0) < 0,5 1.0 - 6.0
Palmitic (C16:0) 7.0 - 14.0 20.0 - 37.0
Stearic (C18:0) 1.4 - 5.5 25.0 - 40.0
Oleic (C18:1) 19.0 - 30.0 31.0 - 50.0
Linoleic (C18:2) 44.0 - 62.0 1.0 - 5.0
Linolenic (C18:3) 4.0 - 11.0 -
Table 2. XRF-results of the composition of catalysts.
Catalyst NiO (%) Al2O3 (%) Impurities
5% NiO/Al2O3 5.33 94.62 0.05
10% NiO/Al2O3 11.47 88.47 0.06
25% NiO/Al2O3 25.73 73.88 0.09
Table 3. Morphologic characteristic of catalysts obtained.
Catalyst BET
Pore volume
Average pore
diameter (ǻ)
5% NiO/Al2O3 175.38 0.48 85.68
10% NiO/Al2O3 164.56 0.44 84.60
25% NiO/Al2O3 160.53 0.40 84.06
phase has peaks less visible because it has the least
amount of NiO in the catalyst (Figure 2).
2.2. Reaction Procedure – Hydrolysis of
Soybean Oil and Tallow
Reactions were performed in a stainless steel 300 mL
batch reactor (Parr Instruments 4842), maximum pres-
sure of 3000 psi and equipped with a sample withdrawal,
stirring, and heating system. Stirring velocity was kept
constant (250 rpm). Reaction mixture consisted of 100 g
of raw material and 100 g of water, providing a water/
raw material molar ratio of 1.
Reagents were introduced together with the appropri-
ated catalyst mass (10% w/w, in relation raw material)
and time of reaction (1 and 3 hours) was considered
when required temperature (250˚C and 270˚C) was
reached. Products were obtained after 1 and 3 hours of
the reaction.
Figure 2. XRD patterns of commercial Al2O3, commercial nio
and synthesized NiO/Al2O3 catalysts.
2.3. Product Analysis
The goal is to verify the hydrogenation of fatty acids
formed, for this, three analyses will be conducted to de-
fine the production of fatty acids. These are: Free fatty
acid content (FFA), total glycerol and iodine value.
The composition of fatty acid was determinated by
gas chromatography (ASTM D 6584, EN ISO 14105,
EM ISSO 14106). It was also determinated total glycerol
and iodine value. Enzymatic method was used to evalu-
ate total glycerol of samples [8].
Hydrolysis results of soybean oil and tallow at 250
and 270˚C in one hour of reaction are shown in the Ta-
bles 4, and in three hours in the Tables 5. It is noted in
the tables that in one hour of reaction, the values of acid-
ity and iodine are very similar for all experiments (cata-
lyzed and not catalyzed). This effect was observed for
both raw materials.
Results obtained in the reactions without catalyst and
catalyzed with 5 and 10% nickel oxide, did not change
significantly when increasing the reaction time of 1 hour
for 3 hours. (Tables 4 and 5).
In experiments using 25% NiO/Al2O3 were observed
changes in fatty acid profiles produced. After 3 hours of
reaction, iodine value decreased due to saturation of
double bonds (Tables 5). The iodine value decreased 47
and 63% for hydrolysis of soybean oil at 250 e 270C
respectively, and 52 and 70% for tallow [9].
The hydrogenation in-situ was confirmed with the gas
chromatograph analysis. The chromatogram suggest that
occurs preferential hydrogenation of more unsaturated
fatty acids. The fatty acid composition of the hydrolysis
products of soybean oil are reported in Figure 3 and for
tallow in Figure 4.
It was observed increase of saturated fatty acids in the
hydrolysis of soybean oil, 48 and 66% in reactions at
G. C. Díaz et al. / Natural Science 3 (2011) 530-534
Copyright © 2011 SciRes. OPEN ACCESS
Table 4. Soybean oil and Tallow hydrolysis (Reaction time: 1h, Catalysts: 5, 10 and 25% of NiO/Al2O3).
5%NiO/Al2O3 10%NiO/Al2O3 25% NiO/Al2O3 Without catalyst
250˚C 270˚C 250˚C 270˚C 250˚C 270˚C 250˚C 270˚C
Soybean oil:
Glycerol content (%) 2.11 1.24 0.49 0.48 1.36 0.30 1.12 1.01
Acidity (%) 90.57 89.89 89.67 89.89 88.85 87.55 91.25 93.47
Iodine (mgI2/g) 132.22 124.41 130.66 133.01 122.44 139.43 136.82 140.14
Glycerol content (%) 0,01 0,00 0,52 0,14 0,26 0,32 0,37 0,32
Acidity (%) 85.12 88.53 80.26 87.14 89.16 87.77 84.04 89.05
Iodine (mgI2/g) 46,38 37,98 39,94 32,47 41,81 41,50 46.7 42,08
Table 5. Soybean oil and Tallow hydrolysis (Reaction time: 3h, Catalysts: 5, 10 and 25% of NiO/Al2O3).
5%NiO/Al2O3 10%NiO/Al2O3 25%NiO/Al2O3 Without catalyst
250˚C 270˚C 250˚C 270˚C 250˚C 270˚C 250˚C 270˚C
Soybean oil:
Glycerol content (%) 2.32 1.04 1.16 1.00 0.43 0.85 1.38 0.89
Acidity (%) 90.04 86.34 82.38 83.35 87.57 85.50 88.67 87.70
Iodine (mgI2/g) 152.25 141.89 139.72129.91 70.91 47.70 135.24 130.36
Glycerol content (%) 2.09 1.52 0.60 0.30 0.17 0.15 0.42 0.44
Acidity (%) 85.84 86.34 93.45 85.92 87.55 93.55 87.04 83.72
Iodine (mgI2/g) 41.95 47.48 44.25 35.89 14.64 10.62 30.39 35.59
3ho u r1hour 2hour
FattyAc i dComposition(% )
1hour 2hour
Fat tyAci dCompositio n(% )
(a) (b)
Figure 3. Fatty acid composition of hydrolysis – hydrogenation of soybean oil, using 25% NiO/Al2O3, reaction time: 3 h. (a)
Temperature: 250˚C (b) Temperature: 270˚C.
1hour 2hou r
Fat t yAc i dC ompo s ition(%)
3ho ur
1hour 2ho ur
FattyAc i dComposition(%)
(a) (b)
Figure 4. Fatty acid composition of hydrolysis – hydrogenation of tallow at 250C, using 25% NiO/Al2O3, reaction time: 3
h. (a) Temperature: 250˚C (b) Temperature: 270˚C.
G. C. Díaz et al. / Natural Science 3 (2011) 530-534
Copyright © 2011 SciRes. OPEN ACCESS
250 and 270˚C, respectively, being 17 and 20% in reac-
tions with tallow.
Changes in fatty acid profile is due to the hydrogena-
tion of double bonds of fatty acids produced. The glyc-
erol formed during the hydrolysis of triglycerides in soy-
bean oil and tallow acts as hydrogen donor. The catalytic
reforming of glycerol allowed in-situ generation of hy-
drogen, which is attracted to and reacts rapidly with the
double bonds.
During the 3 hours of hydrolysis of soybean oil, using
catalyst 25% NiO/Al2O3, are hydrogenated linoleic acid
and oleic acid [10]. Studies of the kinetics of hydrogena-
tion of these acids show that the rate of hydrogenation of
linoleic acid is greater than oleic and stearic [11-13].
Geometry configuration, chemical and physical char-
acteristics of catalyst will determine the selectivity, that
is possible observe by selectivity ratio of different fatty
Selectivity Hydrogenation means that hydrogen is
added first to the most unsaturated fatty acids. The high
selectivity denotes low level of polyunsaturated fatty
acids and high level of monounsaturated. The selectively
hydrogenated product is more resistant to oxidation due
to the preferential hydrogenation of polyunsaturated ac-
ids. In this study, selectivity can be defined as the con-
version of the linolenic acid to oleic acid, compared to
the conversion of linoleic acid to stearic acid.
Linolenic LinoleicOleicStearic
K1, K2 and K3 are kinetic constants.
It is observed that in the hydrolysis of soybean oil, li-
noleic acid was completely hydrogenated (more to 95%),
this results demonstrates the high selectivity of hydro-
genation. Similar result was shown in the reaction with
tallow, transforming linoleic acid into oleic acid.
To corroborate quantitatively these results were cal-
culated the selectivities for hydrogenation of linoleic and
linolenic acids in the following reactions:
Table 6. SR of linoleic and linolenic acids during hydrolysis – hydrogenation of soybean oil and tallow at 250 and 270˚C, using 25%
Temperature: 250C 270C
Reaction time (hours): 1 h 2 h 3 h 1 h 2 h 3 h
Soybean oil:
Linoleic acid
Lo 52.63 52.63 52.63 48.52 48.52 48.52
S 4.00 8.00 14.23 5.00 16.00 33.18
So 3.52 3.52 3.52 4.13 4.13 4.13
K2 = 1 – Lo 47.37 47.37 47.37 51.48 51.48 51.48
K3 = S – So 0.48 4.48 10.71 0.88 11.88 29.05
SR =K2/K3 98.22 10.57 4.42 58.83 4.33 1.77
Linolenic acid
Lno 2.28 2.28 2.28 3.75 3.75 3.75
O 31.00 40.00 69.23 31.90 38.00 51.29
Oo 30.29 30.29 30.29 31.30 31.30 31.30
K1 = 1 – Lno 97.72 97.72 97.72 96.25 96.25 96.25
K2 = O – Oo 0.71 9.71 38.93 0.60 6.70 19.98
SR =K1/K2 138.59 10.07 2.51 161.49 14.37 4.82
Linoleic acid
Lo 1.18 1.18 1.18 0.96 0.96 0.96
S 28.50 32.00 39.01 28.73 31.90 43.12
So 27.95 27.95 27.95 28.18 28.18 28.18
K2 = 1 – Lo 98.82 98.82 98.82 99.04 99.04 99.04
K3 = S – So 0.55 4.05 11.06 0.54 3.72 14.93
SR =K2/K3 181.21 24.43 8.94 182.22 26.65 6.63
G. C. Díaz et al. / Natural Science 3 (2011) 530-534
Copyright © 2011 SciRes. OPEN ACCESS
- Hydrolysis of soybean oil at 250˚C and 270˚C, using
25% NiO/Al2O3 as catalyst, at 1, 2 and 3 hours of reac-
tion time.
- Hydrolysis of tallow at 250˚C and 270˚C, using 25%
NiO/Al2O3 as catalyst, at 1, 2 and 3 hours of reaction
Linoleic and linolenic acids selectivity was estimated
from the selectivity ratio (SR). SR was calculated using
Allen’s method [14] as original proposed by Albright
SR is defined as K2/K3, where K2 = l – Lo, K3 = S – So.
Lo and So represent the linoleic and stearic acid contents
in the original raw material and L and S in the hydro-
genated sample. In the same manner the selectivity ratio
(SR) regarding linolenic acid is calculated by: SR=K1/K 2,
K1 = 1 – Lno, K2= O – Oo, Lno and Oo represent the lino-
lenic and oleic acid contents in the original raw material
and Ln and O in the hydrogenated sample. The results
for soybean oil and tallow are reported in Table 6.
During the hydrogenation of raw materials the selec-
tivity ratios (SR) were high, thus can be assumed that the
reactions were selective under these conditions.
The selectivity can be increased with the temperature,
or by increasing the pressure and agitation. Analyzing
the influence of temperature on SR, it is observed that
increasing the temperature of the reaction of soybean oil
using catalyst 25% NiO/Al2O3 decreases the selectivity
of linoleic acid and increases the selectivity of linolenic
acid. In comparison, the temperature has not significant
influence on the reaction with tallow.
Results of high selectivity in hydrogenation of linoleic
acid and linolenic acid were observed only in reactions
catalyzed by 25% NiO/Al2O3, it is known that commer-
cially employed Ni catalyst has a limited linoleic selec-
tivity [15].
The hydrolysis of soybean oil and tallow were studied
in this paper. Hydrogenation occurs in-situ during the
hydrolysis, producing large amount of saturated and
mono unsaturated fatty acids, such as stearic and oleic
acids. These effects were best manifested under 3 hours
of the reaction and with the catalysts 25% NiO/Al2O3.
The glycerol formed during the hydrolysis behaves as
a hydrogen donor. The reform of the glycerol generates
the in-situ hydrogen, hydrogenating the fatty acids pro-
duced. High hydrogenation selectivity of linoleic and
linolenic acid were observed in the reactions using 25%
NiO/Al2O3. It was not observed hydrogenation of un-
saturated fatty acids during the hydrolysis using 5 and
10% NiO/Al2O3.
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