共查询到20条相似文献,搜索用时 0 毫秒
1.
A kinetic study of the reaction between terephthalic acid and ethylene oxide at atmospheric pressure
Subhash Bhatia M. Gopala Rao M. Someswara Rao 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(6):295-304
The kinetics of the reaction of terephthalic acid with ethylene oxide, in n-butanol solvent, catalysed by triethyl amine, were investigated in a semi-batch reactor under atmospheric conditions. It was found that the reaction occurred in the liquid phase and that mass transfer effects were absent. The reaction was found to be pseudo-zero order in terephthalic acid and first order in ethylene oxide and in catalyst concentration. The effects of reaction temperature, catalyst concentration, particle size of terephthalic acid, ethylene oxide flow rate, stirrer speed and terephthalic acid to ethylene oxide ratio were studied. Particle size of terephthalic acid, stirrer speed and flow rate of ethylene oxide did not affect the reaction rate. The Arrhenius activation energy of the reaction was found to be between 19.2 and 23.5 kcal/mol. 相似文献
2.
A kinetic study of the reaction between terephthalic acid and ethylene oxide at atmospheric pressure
Subhash Bhatia M. Gopala Rao M. Someswara Rao 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(1):295-304
The kinetics of the reaction of terephthalic acid with ethylene oxide, in n-butanol solvent, catalysed by triethyl amine, were investigated in a semi-batch reactor under atmospheric conditions. It was found that the reaction occurred in the liquid phase and that mass transfer effects were absent. The reaction was found to be pseudo-zero order in terephthalic acid and first order in ethylene oxide and in catalyst concentration. The effects of reaction temperature, catalyst concentration, particle size of terephthalic acid, ethylene oxide flow rate, stirrer speed and terephthalic acid to ethylene oxide ratio were studied. Particle size of terephthalic acid, stirrer speed and flow rate of ethylene oxide did not affect the reaction rate. The Arrhenius activation energy of the reaction was found to be between 19.2 and 23.5 kcal/mol. 相似文献
3.
Kinetics of the reaction between terephathalic acid and ethylene oxide, catalysed by triethylamine, was studied in a high-pressure reactor without using solvent. This reaction was carried out at a temperature range of 80–100°C and at a pressure range of 10–15 Kg/cm2 beyond the corresponding vapor pressure of ethylene oxide. Effects of temperature, catalyst concentration, mole ratio of ethylene oxide to terephthalic acid, particle size of terephthalic acid, pK value of the tertiary amine and stirrer speed were experimentally investigated on the yield of bis(2-hydroxyethyl) terephthalate and reaction rates. It was found that the bulk reaction of terephthalic acid with ethylene oxide occurred in the liquid phase. Based on experimental results a reaction mechanism to synthesize bis(2-hydroxyethyl) terephthalate from terephthalic acid and ethylene oxide in a nonsolvent system was proposed, and rate constants were obtained with a model based on this proposed reaction mechanism. The activation energy of the reaction was found to be between 3.67–8.28 kcal/mole in the temperature range of 80–95°C. 相似文献
4.
David R. Fagerburg 《应用聚合物科学杂志》1985,30(9):3617-3623
The kinetics of the reaction of terephthalic acid with a number of ethylene carbonates in the presence of an amine catalyst were examined. All reactions apparently follow first-order kinetics; therefore, the solution rate of TPA is not rate-limiting. With minor adjustments, the mechanism appears to be in accord with that of the model reaction of benzoic acid and ethylene carbonate previously reported. Attack of the carboxylate on the carbonate ring must be the rate-limiting step. Substituent effects (owing to substituents on the carbonate ring) appear to be mostly steric in nature; surprisingly, an n-octyl group causes the slowest reaction. Besides being strongly influenced by steric hinderance, the transition state appears to be highly polar. Activation energy (16.0 kcal/mol) and activation entropy (?23.6 cal/deg) are very similar to those of the model reaction. 相似文献
5.
The chemical kinetics of the monoesterification between terephthalic acid (TPA) and 1,4-butanediol (BDO) catalyzed by a metallo-organic compound was studied using the initial rate method. The experiments were carried out in the temperature range of 463-483 K, and butylhydroxyoxo-stannane (BuSnOOH) and tetrabutyl titanate [Ti(OBu)4] were used as catalyst respectively. The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO (or TPA) with the concentration of TPA (or BDO) kept constant. The reaction orders of reagents were determined by the initial rate method. The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively. However, the order for BDO is the same 0.9 for the two catalysts. Furthermore, the effects of temperature and catalyst concentration are investigated, and the activation energies and the reaction rate constants for the two catalysts were deter-mined. 相似文献
6.
7.
Toshiro Yamada 《应用聚合物科学杂志》1994,51(7):1323-1337
Simulations were carried out with a continuous recycle esterification model for the terephthalic acid–ethylene glycol (TPA–EG) system proposed previously. The influence of reaction temperatures, recycle ratios, and residence times on the oligomer characteristics was examined and the following results were obtained: (1) The main reactions proceed more under higher reaction temperatures, but the side reactions on diethylene glycol (DEG) proceed further than do the main reactions. (2) The higher residence time ratio of the first reactor to the total results in the proceeding of esterifications, which becomes remarkable as the temperature becomes high. (3) As the recycle ratio becomes high, the esterfications proceed, but in the very high degree of esterification, the tendency is reversed. (4) The characteristics of oligomer are almost the same at the same degree of esterification, independent of the reaction conditions. © 1994 John Wiley & Sons, Inc. 相似文献
8.
9.
10.
The base-catalyzed reaction of ethylene oxide with oleic acid can be divided into two stages. The first stage consists of
a slow reaction of oleic acid with ethylene oxide to form principally ethylene glycol monooleate; other reactions such as
esterification, transesterification and polyglycol formation lag behind. In the second stage, after the addition of approximately
one mole of ethylene oxide, the reaction accelerates and transesterification equilibrium is rapidly attained. The composition
of products containing several molecules or more of ethylene oxide can be calculated satisfactorily on the assumption of random
addition of ethylene oxide and random esterification of the hydroxyl groups. The uncatalyzed reaction is much slower and transesterification
equilibrium is attained slowly, if at all. A reaction mechanism based on the difference in basicities of the carboxylate and
alkoxide ions (and the relative rates of the competitive ethylene oxide reactions) is presented for the base-cat-alyzed reaction. 相似文献
11.
Effect of diantimony trioxide on direct esterification between terephthalic acid and ethylene glycol
Toshiro Yamada 《应用聚合物科学杂志》1989,37(7):1821-1835
Experiments at various Sb2O3 concentrations were made in a pilot plant and the effect of Sb2O3 on continuous esterification between terephthalic acid (TPA) and ethylene glycol (EG) was obtained. Reaction rate constants of the previously reported reaction scheme were determined to fit with the experimental data obtained. It was found that the effect of Sb2O3 on reaction rate constant (ki) can be expressed as follows.
- k1 = (3.75 × 10?4Sb + 1.0) × 1.5657 × 109exp(?19,640/RT)
- k2 = (4.75 × 10?4Sb + 1.0) × 1.5515 × 108exp(?18,140/RT)
- k3 = (6.25 × 10?4Sb + 1.0) × 3.5165 × 109exp(?22,310/RT)
- k4 = (4.50 × 10?4Sb + 1.0) × 6.7640 × 107exp(?18,380/RT)
- k5 = (3.50 × 10?4Sb + 1.0) × 7.7069 × exp(?2810/RT)
- k6 = (1.75 × 10?4Sb + 1.0) × 6.2595 × 106exp(?14.960/RT)
- k7 = (3.75 × 10?4Sb + 1.0) × 2.0583 × 1015exp(?42,520/RT)
- 1 Sb2O3 accelerates the esterification reaction between TPA and EG.
- 2 Sb2O3 accelerates the main reaction and its effects on side reactions are minor. The higher the addition rate of Sb2O3, the lower the carboxyl end-group concentration (AV) and diethylene glycol content (DEG).
- 3 The comparison between simulation with potassium titanium oxyoxalate (PTO) in the previous report and with Sb2O3 in the present report shows that the acceleration of polycondensation reaction by Sb2O3 is higher. DEG formation rate is lower with PTO than Sb2O3.
12.
13.
Conclusions 1. A closed-system analysis was carried out of the kinetics and process equilibrium of the formation of dimer 1 which is one of the basic products of the initial state of the poly-esterification reaction of terephthalic acid and ethylene glycol.2. It was established that the hydrolysis of dimer 1 proceeds along only one complexester bond and results in the formation of TPA and BHET.3. The kinetic parameters of the esterification reaction MHET + MHET and the thermodynamic characteristics of the reaction TPA + BHET were determined.4. The rate and equilibrium constants of the reactions MHET + BHET and TPA + MHET were calculated in the first approximation.All-Union Scientific-Research Institute for Synthetic Fibres. Translated from Khimicheskie Volokna, No. 1, pp. 17–20, January–February, 1976. 相似文献
14.
T. Yamada 《应用聚合物科学杂志》1992,45(4):731-744
A new mathematical model has been derived for a semicontinuous recycle esterification process that consists of two reactors, one has the recycle flow to or from another and the discharge flow of the main flow and another has only recycle flow without the discharge flow. This model can give useful information about the optimum design of a new plant through the predictions of oligomer characteristics such as concentrations of carboxyl and hydroxyl end groups, number-average molecular weight, number-average degree of polymerization, esterification and saponification degree, diethylene glycol content, melting point, concentrations of ethylene glycol and water in the vapor phase, and so on. 相似文献
15.
16.
17.
18.
Manoranjan Santra Sunanda K. Palit 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1977,27(1):229-235
Terephthalic acid was obtained from p-dichlorobenzene, carbon monoxide and water when the reaction was carried out in the presence of nickel iodide supported on silica gel (Ni:SiO2 = 50:50) the catalyst which showed the best catalytic activity among those tested. The maximum conversion of p-dichlorobenzene to terephthalic acid at the optimum conditions was 14.9%. 相似文献
19.
20.
Toshiro Yamada 《应用聚合物科学杂志》1992,45(11):1919-1936
A new mathematical model for a continuous recycle esterification process has been derived by basically the same procedure as the continuous process of a cascade type, reported earlier, which includes material and heat balances. Such a model can give extensive information about the optimum design of a new plant through the predictions of oligomer characteristics (concentrations of carboxyl and hydroxyl end groups, number average molecular weight, number average degree of polymerization, esterification and saponification degree, DEG content, melting point of oligomer, etc.), distillate properties (concentrations of EG and water in the vapor phase), heat transfer area, mass flow rate of heating medium, amount of heat supplied by heating medium, enthalpy moving with recycle, and amount of heat removed from each reactor. © 1992 John Wiley & Sons, Inc. 相似文献