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Chemistry and Industry of Forest Products ›› 2019, Vol. 39 ›› Issue (6): 81-87.doi: 10.3969/j.issn.0253-2417.2019.06.011

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Thermal Stability and Decomposition Kinetics of Extracts from Rhus verniciflua Stokes Woods

Hongxia CHEN1(),Chengzhang WANG1,2,*(),Jianzhong YE1,Hao ZHOU1,2,Ran TAO1,Wenjun LI1   

  1. 1. Institute of Chemical Industry of Forest Products, CAF; National Engineering Lab. for Biomass Chemical Utilization; Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; Key Lab. of Biomass Energy and Material, Jiangsu Province, Nanjing 210042, China
    2. Research Institute of Forestry New Technology, CAF, Beijing 100091, China
  • Received:2019-07-04 Online:2019-12-28 Published:2019-12-21
  • Contact: Chengzhang WANG E-mail:shirenyahui@126.com;wangczlhs@sina.com
  • Supported by:
    江苏省生物质能源与材料重点实验室开放基金资助项目(JSBEM-S-201908);国家重点研发计划资助(2017YFD0601305)

Abstract:

Thermal decomposing curves of extracts from Rhus verniciflua Stokes woods(RWE) were obtained in the nitrogen atmosphere by TG-DTG techniques. Five thermal analysis kinetic methods (Kissinger, Flynn-Wall-Ozawa(FWO), Friedman, Coats-Redfern and Achar) were used to speculate the probable mechanism of thermal decomposing reaction and the kinetic parameters including activation energy (Ea) and pre-exponential factor (A). Thermodynamic parameters and the theoretical shelf life of RWE extracts were calculated on the basis of Ea and A at the first stage. With the heating rate increasing, thermal decomposing tempreture of RWE was increased gradually. The TG curve showed the decomposition of RWE could be divided into two steps. The first weight loss rate was from 189.09 to 266.59℃ and the second weight loss rate was from 266.59 to 377.79℃. There were two main weightlessness peaks in DTG curve in the two steps of thermal decomposition. The max thermogravimetric rate temperature was 248.3 and 306.2℃, respectively, and the total weight loss rate was 57.94%. The most probable kinetic methanisms of the first stage thermal decomposition were Avrami-Erofeev equation (random nucleation and subsequent growth, n=3/4), g(α)=[-ln(1-α)] 3/4, f(α)=4/3(1-α)[-ln(1-α)] 1/4. The average apparent activation energy(Ea) was 101.353 kJ/mol, the pre-exponential factor(A) was 7.9×1010 min-1, ΔG was 77.799 kJ/mol, ΔH was 96.978 kJ/mol, and ΔS was 36.446 J/mol. The theoretical shelflife of RWE at room temperature under nitrogen atmosphere was about 1.5-2 years.

Key words: Rhus verniciflua stokes woods extracts, thermal analysis, thermal decomposition kinetics

CLC Number: