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Ma Y.,University of Sichuan | Yang Q.,Chengdu Huien Fine Chemical Co. | Jiang W.,University of Sichuan
Shiyou Huagong/Petrochemical Technology | Year: 2014

Thermodynamic analysis for the synthesis of poly (butylene succinate) from 1, 4-butanediol and succinic acid (reaction (1)), 1, 4-butanediol and succinic anhydride (reaction (2)), or 1, 4-butanediol and dimethyl succinate (reaction (3)) were conducted by group contribution methods. The relationships between the molar enthalpy changes, molar Gibbs free energy changes and equilibrium constants of the reactions, and temperature in the range of 298.15-498.15 K were established. The results showed that reactions (1)-(3) could take place spontaneously; reaction (2) was exothermic, and reactions (1), (3) were exothermic in liquid state and endothermic in gas state; all the equilibrium constants of reaction (1)-(3) were large, which indicated that the reactions were feasible. Moreover, reaction (2) was the easiest due to its small molar Gibbs free energy change and large equilibrium constant. Source


Rao L.,University of Sichuan | Yang Q.,Chengdu Huien Fine Chemical Co. | Jiang W.,University of Sichuan
Petroleum Processing and Petrochemicals | Year: 2014

A novel charcoal-based sulfonated solid acid was synthesized through carbonation and then sulfonation of the bamboo charcoal using chlorosulfonic acid. The esterification of sebacic acid and n-butyl alcohol was taken as the model reaction to investigate the impact of preparation parameters on the catalyst activity. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo gravimetric analysis (TGA) were used to characterize the catalyst. The results show that the charcoal-based solid acid catalyst has amorphous carbon structure and the catalyst prepared at the optimal conditions of carbonization at 325 °C for 1 h and then sulfonation at room temperature for 2 h with acid-bamboo charcoal ratio of 2. 5 mL/g exhibits a higher catalytic activity. Its acid amount can reach 1. 77 mmol/g. The conversion rate of sebacic acid reaches 99. 14% at the following conditions: n-butyl alcohol to sebacic acid mole ratio 3. 0, the amount of charcoal-based sulfonated solid acid for 2% of sebacic acid, 3 mL cyclohexane, and reaction time 100 min. After repeated use 4 times, sebacic acid conversion rate remains above 80%, indicating the good regeneration performance. Source


Dong J.,University of Sichuan | Tian X.,University of Sichuan | Sun X.-Y.,University of Sichuan | Jiang W.-W.,University of Sichuan | And 2 more authors.
Procedia Engineering | Year: 2011

The nitration of 1,2,3-trichlorobenzene are studied in the binary system of sulfuric acid and nitric acid. The effect of molar ratio of raw materials,reaction temperature and reaction time on the yield are evaluated in the system of nitric acid/sulfuric acid.The optimum process parameters are selected in the system of 98% of sulfuric acid and 65% of nitric acid as follows: n(1,2,3-trichlorobenzene):n( sulfuric acid ):n(nitric acid)= 1:11.3:2.3,reaction temperature 65?and reaction time 4.5 h.The yield of 4,6-dinitro-1,2,3-trichlorbenzene is 93.95%.The concentration of waste acid can reach to about 95% by extracting and distilling in vacuo. Both the sulphuric acid and residue after recrystallization can be recycled as starting materials in another synthetic reaction of 4,6-dinitro-1,2,3-trichlorbenzene,the product is obtained in yields greater than about 94 mole percent with purity being greater than about 99w%,The structure of target product is characterized by IR,HPLC and Element analysis. © 2010 Published by Elsevier Ltd. Source


Meng X.,University of Sichuan | Chen Y.,University of Sichuan | Sun X.-Y.,University of Sichuan | Jiang W.-W.,University of Sichuan | And 2 more authors.
Xiandai Huagong/Modern Chemical Industry | Year: 2012

Uniform design was applied to study the synthesis of linear poly (p-phenylene sulfide) resin with high molecular weight (HMW PPS). The effects of reaction temperature, reaction time, the molar ratio of reaction monomers, the amount of solvent and catalyst on the yield of HMW PPS were investigated. The optimal reaction conditions were found by using multiple regression analysis based on the data obtained from uniform design experiments. The optimized conditions are as follows: 210.9°C and 2.8 hours of reaction temperature and reaction time, respectively, in the early stage, 270°C and 2.5 hours of reaction temperature and reaction time, respectively, in the late stage, 1.1:1 of molar ratio of Na 2S·9H 2O and para-dichlorobenzene, 550 mL:1 mol of ratio of NMP and para-dichlorobenzene, and 20 g:1 mol of the additive and para-dichlorobenzene. The molecular weight of the obtained HMW PPS is close to 60000. The product yield is up to 93.7%. Both the solvent and the catalyst can be reused without complex recovering process. After several times of recycling, the yield of the product is still up to 91.2%. The obtained product is characterized by thermal analysis, IR and element analysis. Source

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