Study on Synthesis of Dibutyl Succinate Catalyzed by Phosphtungstic Acid and its Reaction Kinetics

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1 2 4 No.4 Vol Journal of Chemical Engineering of Chinese Universities Aug (2007) ,,,, (, ) 3.0: h 99.47% Ea = kj mol k 0 = mol L min TQ O A Study on Synthesis of Dibutyl Succinate Catalyzed by Phosphtungstic Acid and its Reaction Kinetics SUN Xiao-Bo, HUANG Qiang, REN Ke, FENG Yang, LIU Guo-ji (Department of Chemical Engineering, Zhengzhou University, Zhengzhou , China) Abstract: Dibutyl succinate was synthesized by using succinate acid and n-butanol as reactants, phosphotungstic acid as catalyst and toluene as azeotropic agent. The optimum synthesis conditions affecting the yield of dibutyl succinate, such as the amount of catalyst, molecular ratio of n-butanol to succinate acid, amount of azeotropic agent used and reaction time, were investigated by the experiments according to uniform design. The results indicate that 99.47% yield of dibutyl succinate could be obtained with following optimal reaction conditions: the molecular ratio of n-butanol to succinate acid 3.0:, the amount of catalyst.% by mass of acid, the amount of azeotropic used 22% of total mass and the reaction time 2 h. The kinetic parameters, such as the apparent activation energy Ea and the frequency factor k 0, were obtained by regression of the experimental data achieved under various reaction conditions, and the kinetic equation of the esterification reaction was proposed. According to the kinetic equation proposed, the synthetic reaction of dibutyl succinate is a second order irreversible reaction. The proposed kinetic equation was also examined by the experimental results and got a satisfactory result. Key words: dibutyl succinate; synthesis; uniform design; kinetics ( ) [~6] ( ) (977-) guojiliu@zzu.edu.cn

2 [7,8] ( ) Keggin H 3 PW 2 O 40 ( ) 2.2 XK78-2 ( ) IR-408 AB204-N ~50 /533 Pa( [9] 45 /533 Pa) 95~5 2.4 =( / ) 00, IR (KBr) ( ) [9] 2.5 U 8 (4 3 8 ) Table Table of U 8 (4 3 8 ) uniforml design Molar The amount The amount of Reaction Yield of No. ratio of cat./ % azeotropic agent / % time / h esterification / % U 8 ( ) SPSS Y = X X X XX2 +.76X3X4 SPSS X =2.98 X 2 =.65% X 3 =22.25% X 4 =2 h Y = 99.74%

3 % Ratios of alcohol to succinate acid Fig. Effect of ratios of alcohol to succinate acid on yield of esterification Amount of catalyst in total mass of acid / % 2 Fig.2 Effect of amount of catalyst on yield of esterification % (wt).%(wt) % Amoubt of azeotyopic solvent / % 3 Fig.3 Effect of amount of azeotropic solvent on yield of esterification Reaction time /min 4 Fig.4 The relation between yield of esterification and reaction time % 2 h %

4 r min r min 4.2 [0] k A+ B R+ H2O k2 R+ B S+ H2O A B R S Q n A n R n S n W = 2n S + n R n NaOH = 2n A + n R 2 = nnaoh + nw Y = n A = n NaOH /2 ( n R = 0) dca α β r = = kc A CB () k C A C B t α β C α = β = B,0 =Q CA,0 dca r = = kc ACB (2) A C A,0 = V C = C ( Y) C B =C A,0 ( Q 2 Y) A A,0 dy C = k A,0 C ( Y) C ( Q 2 Y) (3) A,0 A,0 dy Q 2Y Y I = k i 0 t= ln C 2 2 A0, ( Y)(Q Y) C A,0 (Q ) Q( Y) = I i =kt I i t Y I i I i I i t I i - t 5 I i t k α=β= (4)

5 Ii / mol L K K K K lnk / L mol min Y = X R = t / min 5 I i - t Fig.5 Relation on experiment I i and different time at viarious temperatures / T / K 6 Fig.6 Effect of temperature on apparent reaction rate constant lnk lnk /T k 0 6 Arrhenius Ea/ 0e k = k (5) lnk ~ T Ea lnk= + lnk 0 (6) lnk= (7) T R 2 = Ea = = J mol = kJ mol k 0 = e = mol L min dca r= = e CACB (mol L min ) (8) 4.3 Q 2Y (4) kt= ln C (Q 2 ) Q( Y) A0, T K kt ( Q 2) CA,0 Q( e ) Y= kt ( Q 2) CA,0 e Q T 3 k = e = L min mol Q =3.0 C A,0 =.5568 k Y t Y cal K Y exp 2 5% (9)

6 K Table 2 The experimental ratio of esterification compared with the calculated ratio of esterification at 378.5K Yexp Ycal Yexp Y t / min Y exp / % Y cal / % /% t / min Y Y exp / % Y cal / % Y exp cal exp / % 5 () (2) 3.0: h (3) 95~5 2.5~ r= e C C A B [] XIANG Shi-rong( ), YU Shan-xin( ). Synthesis of dibutyl succinate catalyzed by p-toluene sulfonic acid( ) [J]. Tianjin Chemical Industry( ), 2004, 8(5): [2] ZI Jun-feng( ), ZHU Lei( ). Synthesis of dibutyl succinate catalyzed by magnetic solid superacid ZrO 2 /SO 4 ( ZrO 2 /SO 2-4 ) [J]. Industrial Catalysis( ), 2004, 2(2): [3] ZHONG Tong-sheng( ), WEN Rui-ming( ), YU Shan-xin( ). Synthesis of dibutyl succinate catalyzed by stannic chloride( ) [J]. Journal of Beijing Technology and Business University(Natural Science Edition)( ( )), 2003, 2(): 7-9. [4] ZHU Lei( ), ZI Jun-feng( ). Catalyzed synthesis of dibutyl succinate by ammonium ferric sulfate( ) [J]. Chemical Industry Time( ), 2004, 8(): [5] LONG Li-ping( ), YANG Zhong-e( ), ZHONG Tong-sheng( ) et al. Synthesis of dibutyl succinate catalyzed by a strong acid cation exchange resin( ) [J]. Chinese Journal of Synthetic Chemistry( ). 2004, (2): [6] ZI Jun-feng( ), ZHU Lei( ). Catatytic synthesis of dibutyl succinate with sodium bisulfate( ) [J]. Journal of Jilin Institute of Chemical Technology( ), 2003, 20(3): 0-2. [7] LI Dan-na( ), ZHOU Hui( ), ZHANG Pu-yu( ). Progress in research on esterification reactions caralyzed by heteropolyacid( ) [J]. Journal of Henan Instirute of Education(Natural Science)( ( )), 2004, 3(3): [8] LIAO De-zhong( ). A study on catalytic esterification of adipic acid and alkyl alchohol with tungstophosphoric acid( ) [J]. Journal of Yueyang Noumal University(Natural Sciecce)( ( )), 2000, 3(4): [9] Grasselli J G, Ritchey W M. Atlas of Spectral Data and Physical Constants for Organic Compounds. 2nd Ed. [M]. Cleveland: CRC Press Inc,975, :546.. [0] LIU Xin-peng( ), WU Tian-xiang( ). Reaction kineticss of esterification of synthetic dioctyl terephthalate with nonacid catalyst( ) [J]. J Chem Eng of Chinese Univ( ), 994, 8(2):

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