International Journal of Scientific & Engineering Research, Volume 4, Issue 10, October-2013 1086
ISSN 2229-5518
Study on synthesis of butyl oleate catalyzed by ceric ammonium sulfate
Xu Long, Li Jian, Yang Lina*, Sun Yumeng, Dong Jiali
(School of Petroleum and Chemical Technology, College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 113001, China)
tion conditions on esterification were investigated by orthogonal experimental design. The results showed that the conversion of 97.1% was attained under the optimum reaction condition as follows: reaction temperature 140 ℃, reaction tim e 2.5 h, the molar ratio of n-butanol to oleic acid 2.5:1, and the amount of catalyst 5%(wt), the esterification conversion can still reach 60.1% after four times of repeated uses.
Index Terms— Butyl oleate; Ammonium ceric sulfate; Catalytic; Esterification
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UTYL oleate (n-butyl oblate) is a kind of long-chain fatty acid ester with carbon-carbon unsaturated double bond. It has good performances in such applications such as plas-
ticizer, lubricating oil additives, wetting agent and industrial solvents etc. Traditional butyl oleate synthesis method starts from oleic acid and n-butanol using concentrated sulfuric acid as catalyst [ . High catalytic activity and low cost make it favor- able in the esterification, but the following disadvantages[1,2]: (1) under the esterification reaction conditions, both concen- trated sulfuric esterification, dehydration and oxidation, ac- companied by side reactions, reaction product containing a small amount of ether, sulfuric acid ester, unsaturated com- pounds and carbonyl compounds, to the product purification and recovery difficult; (2) concentrated sulfuric acid as a cata- lyst subject to alkali neutralization, washing, post-treatment process complex, reaction products and unreacted raw mate- rial loss, accompanied by a large number of waste generated, easy to cause environmental pollution; (3) the reaction of con- centrated sulfuric acid corrosion of equipment seriously. In recent years, there have been reports in solid superacid [3,4], heteropoly acids [5,6], biological enzyme [7,8] as the catalyst for synthesis of butyl oleate, but there is not reports about ce- ric ammonium sulfate as catalyst for the synthesis of butyl oleate. The ceric ammonium sulfate was used as catalyst for the synthesis of methyl oleate in this study, the results show that its catalytic activity is excellent and the reusing ability of the catalyst is outstanding.
Oleic acid(AR, T ianjin Hengxing Chemical Reagent Co., Ltd.); N-butanol(AR, Shenyang Sinopharm Chemical Re- agent Co., Ltd.); Ceric ammonium sulfate(AR, Beijing
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• Xu Long postgraduate students engaged in the production of clean fuels in
Liaoning Shihua University, China. E-mail: xulongliaogong@126.com
• Professor Yang Lina* engaged in the production of clean fuesl in Liaoning
Shihua University, China. E-mail: lnqdsd@yahoo.com.cn
Chemical Reagent); Sodium hydroxide(AR, Liaoning Xinxing Reagent Co., Ltd.); Ethanol(AR, Liaoning Xinx- ing Reagent Co., Ltd).
DF-101S collector constant temperature heating magnetic stir- rer(GONGYI YUHUA Instrument Co., Ltd.); AUY220 electron- ic balance(SHANG HUA GUANG ZHENG Medical Instru- ment Co., Ltd.); Magnetic stirrer(XIANG SU TAI XIAN Ana- lytical Instrument Factory).
Some amount of oleic acid, methanol and catalyst were put into a single necked flask with a reflux condenser in a thermo- static heating magnetic stirrer, after the reaction at needed conditions the reaction system was cooled to room tempera- ture.
The acid value before and after the reaction was determined based on GBT1668-2008. and the esterification conversion is calculated as follows:
oleinic acid conversion % =
The initial acid of the reaction - The edd acid of reaction ×100% The initial acid of the reaction
= V0 − Vt ×100%
V0
V 0 , V t —Volume of the NaOH-ethanol solution consumed for the reaction system before and after the reaction respectively.
can be identify in the intricacies of various factors, there are
rules of analysis the impact of indicators of various factors. We
therefore adopted orthogonal experimental design method,
select L9 (34) table, test each factor and horizontal are shown in
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International Journal of Scientific & Engineering Research, Volume 4, Issue 10, October-2013 1087
ISSN 2229-5518
Table 1, testing program and the results are shown in table 2.
TABLE 1
ORTHOGONAL LEVEL OF FORM FACTORS
Note: the amount of catalyst = (mass of catalyst / mass of reactant) × 100%
TABLE 2
EXPERIMENTAL PROGRAM AND RESULTS OF ANALYSIS
90
80
70
60
50
40
30
20
10
0
110 120 130 140 150
Reaction temperature/℃
Fig.1 The affection of reaction temperature to the conversion
The impact of reaction time on the conversion of esterification is studied in fig.2 at such conditions: amount of catalyst 3%,
reaction temperature 140℃, molar ratio 2(butanol 0.03 mol).
95
90
85
80
75
Table 2 shows the influence extent order of each factor: A>B>C>D, and the optimal combination obtained by orthog- onal experiment is A3 B3 C1 D3 , the optimal conditions reaction
is temperature 140℃, reaction time 3.5 h, molar ratio 2, 6% of
the amount of catalyst in the esterification.
The impact of reaction temperature on the conversion of ester- ification is studied in fig.1 at such conditions: amount of cata- lyst 3%, reaction time 2.5 h, molar ratio 2.
It is seen from fig.1 that as the reaction temperature elevated, oleic acid conversion is increasing before140℃ then declined
slightly when the temperature is higher. This is because the esterification reaction is reversible, when the temperature is
below 140℃, the reaction is kinetically controlled, elevated
temperatures conducive to positive reaction direction, the
conversion increased; When the temperature is higher than
140 ℃ , reaction is controlled by thermodynamics, elevated
temperature conducive to endothermic reverse reaction, the
conversion basically unchanged and side reactions may in- crease, therefore the best reaction temperature is 140℃, at this
point esterification conversion was 93.2%.
70
65
60
1.0 1.5 2.0 2.5 3.0 3.5
Reaction time/h
Fig. 2 The affection of reaction time to the conversion
It is seen from fig.2 that as the reaction time increased, oleic acid conversion increased gradually, but the conversion changes slowly when the reaction time is longer than 3 h, then the system has basically reached the equilibrium. Therefore, to determine the optimum reaction time 3 h, the esterification rate was 94.1% at this time.
The impact of molar ratio of the raw material on the conver- sion of esterification is studied in fig.3 at such conditions:
amount of catalyst 3%, reaction temperature 140℃, reaction
time 3 h, oleic acid 0.015 mol.
It is seen from fig.3 that esterification of oleic acid is increased
with molar ratio of the increase, When the molar ratio is 2.5,
reaches a maximum, and then decreased. This is because as the mole ratio increases, relatively lower concentrations of oleic acid, the reaction rate is reduced, thus conversion de- clined, therefore the optimal molar ratio is 2.5.
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ISSN 2229-5518
90
80
70
60
50
1.0 1.5 2.0 2.5 3.0
Molar ratio
Fig. 3 The affection of molar ratio to the conversion
The impact of the amount of catalyst on the conversion of es- terification is studied in fig.4 at such conditions: reaction tem-
perature 140℃, molar ratio 2.5 (n-butanol 0.03 mol), reaction
time 3 h.
90
80
70
60
50
40
30
1 2 3 4 5 6
The amount of catalyst/%
Fig. 4 The affection of the amount of catalyst to the conversion
It is seen from fig.4 that when the amount of the catalyst is less than 3%, with the increase of the catalyst amount, its conver- sion increases significantly. With the increase in volume of catalyst, the rate of synthesis of butyl oleate accelerated, re- ducing the time used for the reaction, so that the synthesis of butyl oleate esterification rate increased, when the amount of ceric ammonium sulfate is more than 3%, further increase of catalyst amount, will not change the conversion significantly. When the amount of ceric ammonium sulfate is 5%, its con- version reached the maximum of 97.1%, Therefore, to deter- mine the optimum amount of catalyst is 5%, then the esterifi- cation rate was 97.1%.
Reusing ability of the catalyst is studied under the optimal experimental conditions, the catalyst was collected by filtra- tion after the reaction, then the catalyst is used for new reac-
tion, every reaction result for each cycle of reaction was shown in table 3.
TABLE 3
THE AFFECTION OF THE REUSING ABILITY OF CATALYST TO THE
CONVERSION
The reusing ability of catalyst | 1 | 2 | 3 | 4 | 5 |
Conversion（%） | 97.1 | 91.8 | 82.4 | 73.9 | 60.1 |
It can be seen from Table 3, along with increase the frequency of use catalyst, esterification catalyst capacity decreased, but still after five times, esterification rate can reach 60.1%, there- fore, the catalyst is stability.
Ceric ammonium sulfate has good catalytic activity and reus- ing ability in the reaction of oleic acid and n-butanol, the pro- cess is simple, and no pollution basically produces. The opti-
mal reaction conditions are: the reaction temperature 140℃,
reaction time 3h, molar ratio of 2.5, ceric ammonium sulfate
catalyst dosage 5%(wt), at such conditions the conversion can
reach 97.1%, and the catalytic performance has no significantly
changes even after five times of reactions.
[1] Kolesnik I G, Zhizhina E G, Matveev K I. Catalytic oxidation of 2,6- dialkylphenols to the corresponding 2,6-dialkyl-1,4-benzoquinones by molec- ular oxygen in the presence of P-Mo-V heteropoly acids [J]. J Mol Catal A: Chemical, 2000, 153: 147-154.
[2] Bassam E A, Fettouhi M. H 3+n PMo 12-n VnO40 -catalyzed selective oxi- dation of benzoins to benzils or aldehydes and esters by dioxygen [J]. J Mol Catal A: Chemical, 2001, 165: 283-290.
[3] Yu Jiwei, Gao Wenyi, Ren Ligu. Synthesis of butyl oleate by using nanosized SO 4 2-/SnO2 solid superacid as catalyst [J]. China Surfac- tant Detergent & Cosmetics, 2007, 37(4): 238-241.
[4] LIAO Dezhong, HE Jieyu, HE Xianming, et al. Synthesis of Butyl
Oleate over Ti(SO4 )2 /SiO2 Catalyst [J]. Chemistry World, 2001, 43(1):
40-42.
[5] Yu Xinwu, Cai Chuanzhi, Zhang Lu. Catalytic synthesis of n-butyl oleate by heteropolyacid supported on TiO2 -MoO3 [J]. Journal of Chemical Industry & Engineering, 2006, 27(1): 33-36.
[6] Luo Genxiang, Wang Jing, Liu Chunsheng, et al. Catalytic Synthesis of Butyl Oleate by Bismuth Phosphotungstate [J]. Journal of Pero- chemical Universities, 2010, 23(3): 44-47.
[7] Habulin M C, Knez Z. Enzymatic synthesis of n-butyl oleate in a hollow fiber membrane reactor [J]. Joumal of Membrane Science,
1991, 61: 315-324.
[8] Ghamgui H, Chaabouni M K, Gargouri Y. 1-Butyl oleate synthesis by immobilized lipase from Rhizopus oryzae:a comparative study be- tween n-hexane and solvent-free system [J]. Enzyme and Microbial
Technology, 2004, 35: 355-363.
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